security/ccsecurity/util.c

/*
 * fs/ccs_common.c
 *
 * Common functions for SAKURA and TOMOYO.
 *
 * Copyright (C) 2005-2008  NTT DATA CORPORATION
 *
 * Version: 1.6.5-pre   2008/09/11
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */

#include <linux/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
#define __KERNEL_SYSCALLS__
#endif
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/utime.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <stdarg.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 0)
#include <linux/namei.h>
#include <linux/mount.h>
static const int lookup_flags = LOOKUP_FOLLOW;
#else
static const int lookup_flags = LOOKUP_FOLLOW | LOOKUP_POSITIVE;
#endif
#include <linux/realpath.h>
#include <linux/ccs_common.h>
#include <linux/ccs_proc.h>
#include <linux/tomoyo.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
#include <linux/unistd.h>
#endif

/* To support PID namespace. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
#define find_task_by_pid find_task_by_vpid
#endif

/* Set default specified by the kernel config. */
#ifdef CONFIG_TOMOYO
#define MAX_ACCEPT_ENTRY (CONFIG_TOMOYO_MAX_ACCEPT_ENTRY)
#define MAX_GRANT_LOG    (CONFIG_TOMOYO_MAX_GRANT_LOG)
#define MAX_REJECT_LOG   (CONFIG_TOMOYO_MAX_REJECT_LOG)
#else
#define MAX_ACCEPT_ENTRY 0
#define MAX_GRANT_LOG    0
#define MAX_REJECT_LOG   0
#endif

/* Has /sbin/init started? */
bool sbin_init_started = false;

/* Log level for SAKURA's printk(). */
const char *ccs_log_level = KERN_DEBUG;

/* String table for functionality that takes 4 modes. */
static const char *mode_4[4] = {
        "disabled", "learning", "permissive", "enforcing"
};
/* String table for functionality that takes 2 modes. */
static const char *mode_2[4] = {
        "disabled", "enabled", "enabled", "enabled"
};

/* Table for profile. */
static struct {
        const char *keyword;
        unsigned int current_value;
        const unsigned int max_value;
} ccs_control_array[CCS_MAX_CONTROL_INDEX] = {
        [CCS_TOMOYO_MAC_FOR_FILE]        = { "MAC_FOR_FILE",        0, 3 },
        [CCS_TOMOYO_MAC_FOR_ARGV0]       = { "MAC_FOR_ARGV0",       0, 3 },
        [CCS_TOMOYO_MAC_FOR_ENV]         = { "MAC_FOR_ENV",         0, 3 },
        [CCS_TOMOYO_MAC_FOR_NETWORK]     = { "MAC_FOR_NETWORK",     0, 3 },
        [CCS_TOMOYO_MAC_FOR_SIGNAL]      = { "MAC_FOR_SIGNAL",      0, 3 },
        [CCS_SAKURA_DENY_CONCEAL_MOUNT]  = { "DENY_CONCEAL_MOUNT",  0, 3 },
        [CCS_SAKURA_RESTRICT_CHROOT]     = { "RESTRICT_CHROOT",     0, 3 },
        [CCS_SAKURA_RESTRICT_MOUNT]      = { "RESTRICT_MOUNT",      0, 3 },
        [CCS_SAKURA_RESTRICT_UNMOUNT]    = { "RESTRICT_UNMOUNT",    0, 3 },
        [CCS_SAKURA_RESTRICT_PIVOT_ROOT] = { "RESTRICT_PIVOT_ROOT", 0, 3 },
        [CCS_SAKURA_RESTRICT_AUTOBIND]   = { "RESTRICT_AUTOBIND",   0, 1 },
        [CCS_TOMOYO_MAX_ACCEPT_ENTRY]
        = { "MAX_ACCEPT_ENTRY",    MAX_ACCEPT_ENTRY, INT_MAX },
        [CCS_TOMOYO_MAX_GRANT_LOG]
        = { "MAX_GRANT_LOG",       MAX_GRANT_LOG, INT_MAX },
        [CCS_TOMOYO_MAX_REJECT_LOG]
        = { "MAX_REJECT_LOG",      MAX_REJECT_LOG, INT_MAX },
        [CCS_TOMOYO_VERBOSE]             = { "TOMOYO_VERBOSE",      1, 1 },
        [CCS_SLEEP_PERIOD]
        = { "SLEEP_PERIOD",        0, 3000 }, /* in 0.1 second */
};

#ifdef CONFIG_TOMOYO
/* Capability name used by domain policy. */
static const char *capability_control_keyword[TOMOYO_MAX_CAPABILITY_INDEX] = {
        [TOMOYO_INET_STREAM_SOCKET_CREATE]  = "inet_tcp_create",
        [TOMOYO_INET_STREAM_SOCKET_LISTEN]  = "inet_tcp_listen",
        [TOMOYO_INET_STREAM_SOCKET_CONNECT] = "inet_tcp_connect",
        [TOMOYO_USE_INET_DGRAM_SOCKET]      = "use_inet_udp",
        [TOMOYO_USE_INET_RAW_SOCKET]        = "use_inet_ip",
        [TOMOYO_USE_ROUTE_SOCKET]           = "use_route",
        [TOMOYO_USE_PACKET_SOCKET]          = "use_packet",
        [TOMOYO_SYS_MOUNT]                  = "SYS_MOUNT",
        [TOMOYO_SYS_UMOUNT]                 = "SYS_UMOUNT",
        [TOMOYO_SYS_REBOOT]                 = "SYS_REBOOT",
        [TOMOYO_SYS_CHROOT]                 = "SYS_CHROOT",
        [TOMOYO_SYS_KILL]                   = "SYS_KILL",
        [TOMOYO_SYS_VHANGUP]                = "SYS_VHANGUP",
        [TOMOYO_SYS_SETTIME]                = "SYS_TIME",
        [TOMOYO_SYS_NICE]                   = "SYS_NICE",
        [TOMOYO_SYS_SETHOSTNAME]            = "SYS_SETHOSTNAME",
        [TOMOYO_USE_KERNEL_MODULE]          = "use_kernel_module",
        [TOMOYO_CREATE_FIFO]                = "create_fifo",
        [TOMOYO_CREATE_BLOCK_DEV]           = "create_block_dev",
        [TOMOYO_CREATE_CHAR_DEV]            = "create_char_dev",
        [TOMOYO_CREATE_UNIX_SOCKET]         = "create_unix_socket",
        [TOMOYO_SYS_LINK]                   = "SYS_LINK",
        [TOMOYO_SYS_SYMLINK]                = "SYS_SYMLINK",
        [TOMOYO_SYS_RENAME]                 = "SYS_RENAME",
        [TOMOYO_SYS_UNLINK]                 = "SYS_UNLINK",
        [TOMOYO_SYS_CHMOD]                  = "SYS_CHMOD",
        [TOMOYO_SYS_CHOWN]                  = "SYS_CHOWN",
        [TOMOYO_SYS_IOCTL]                  = "SYS_IOCTL",
        [TOMOYO_SYS_KEXEC_LOAD]             = "SYS_KEXEC_LOAD",
        [TOMOYO_SYS_PIVOT_ROOT]             = "SYS_PIVOT_ROOT",
        [TOMOYO_SYS_PTRACE]                 = "SYS_PTRACE",
};
#endif

/* Profile table. Memory is allocated as needed. */
static struct profile {
        unsigned int value[CCS_MAX_CONTROL_INDEX];
        const struct path_info *comment;
#ifdef CONFIG_TOMOYO
        unsigned char capability_value[TOMOYO_MAX_CAPABILITY_INDEX];
#endif
} *profile_ptr[MAX_PROFILES];

/* Permit policy management by non-root user? */
static bool manage_by_non_root = false;

/* Utility functions. */

#ifdef CONFIG_TOMOYO
/**
 * tomoyo_quiet_setup - Set TOMOYO_VERBOSE=0 by default.
 *
 * @str: Unused.
 *
 * Returns 0.
 */
static int __init tomoyo_quiet_setup(char *str)
{
        ccs_control_array[CCS_TOMOYO_VERBOSE].current_value = 0;
        return 0;
}

__setup("TOMOYO_QUIET", tomoyo_quiet_setup);
#endif

/**
 * is_byte_range - Check whether the string isa \ooo style octal value.
 *
 * @str: Pointer to the string.
 *
 * Returns true if @str is a \ooo style octal value, false otherwise.
 */
static bool is_byte_range(const char *str)
{
        return *str >= '0' && *str++ <= '3' &&
                *str >= '0' && *str++ <= '7' &&
                *str >= '0' && *str <= '7';
}

/**
 * is_decimal - Check whether the character is a decimal character.
 *
 * @c: The character to check.
 *
 * Returns true if @c is a decimal character, false otherwise.
 */
static bool is_decimal(const char c)
{
        return c >= '0' && c <= '9';
}

/**
 * is_hexadecimal - Check whether the character is a hexadecimal character.
 *
 * @c: The character to check.
 *
 * Returns true if @c is a hexadecimal character, false otherwise.
 */
static bool is_hexadecimal(const char c)
{
        return (c >= '0' && c <= '9') ||
                (c >= 'A' && c <= 'F') ||
                (c >= 'a' && c <= 'f');
}

/**
 * is_alphabet_char - Check whether the character is an alphabet.
 *
 * @c: The character to check.
 *
 * Returns true if @c is an alphabet character, false otherwise.
 */
static bool is_alphabet_char(const char c)
{
        return (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
}

/**
 * make_byte - Make byte value from three octal characters.
 *
 * @c1: The first character.
 * @c2: The second character.
 * @c3: The third character.
 *
 * Returns byte value.
 */
static u8 make_byte(const u8 c1, const u8 c2, const u8 c3)
{
        return ((c1 - '0') << 6) + ((c2 - '0') << 3) + (c3 - '0');
}

/**
 * str_starts - Check whether the given string starts with the given keyword.
 *
 * @src:  Pointer to pointer to the string.
 * @find: Pointer to the keyword.
 *
 * Returns true if @src starts with @find, false otherwise.
 *
 * The @src is updated to point the first character after the @find
 * if @src starts with @find.
 */
static bool str_starts(char **src, const char *find)
{
        const int len = strlen(find);
        char *tmp = *src;
        if (strncmp(tmp, find, len))
                return false;
        tmp += len;
        *src = tmp;
        return true;
}

/**
 * normalize_line - Format string.
 *
 * @buffer: The line to normalize.
 *
 * Leading and trailing whitespaces are removed.
 * Multiple whitespaces are packed into single space.
 *
 * Returns nothing.
 */
static void normalize_line(unsigned char *buffer)
{
        unsigned char *sp = buffer;
        unsigned char *dp = buffer;
        bool first = true;
        while (*sp && (*sp <= ' ' || *sp >= 127))
                sp++;
        while (*sp) {
                if (!first)
                        *dp++ = ' ';
                first = false;
                while (*sp > ' ' && *sp < 127)
                        *dp++ = *sp++;
                while (*sp && (*sp <= ' ' || *sp >= 127))
                        sp++;
        }
        *dp = '\0';
}

/**
 * ccs_is_correct_path - Validate a pathname.
 * @filename:     The pathname to check.
 * @start_type:   Should the pathname start with '/'?
 *                1 = must / -1 = must not / 0 = don't care
 * @pattern_type: Can the pathname contain a wildcard?
 *                1 = must / -1 = must not / 0 = don't care
 * @end_type:     Should the pathname end with '/'?
 *                1 = must / -1 = must not / 0 = don't care
 * @function:     The name of function calling me.
 *
 * Check whether the given filename follows the naming rules.
 * Returns true if @filename follows the naming rules, false otherwise.
 */
bool ccs_is_correct_path(const char *filename, const s8 start_type,
                         const s8 pattern_type, const s8 end_type,
                         const char *function)
{
        bool contains_pattern = false;
        unsigned char c;
        unsigned char d;
        unsigned char e;
        const char *original_filename = filename;
        if (!filename)
                goto out;
        c = *filename;
        if (start_type == 1) { /* Must start with '/' */
                if (c != '/')
                        goto out;
        } else if (start_type == -1) { /* Must not start with '/' */
                if (c == '/')
                        goto out;
        }
        if (c)
                c = *(strchr(filename, '\0') - 1);
        if (end_type == 1) { /* Must end with '/' */
                if (c != '/')
                        goto out;
        } else if (end_type == -1) { /* Must not end with '/' */
                if (c == '/')
                        goto out;
        }
        while ((c = *filename++) != '\0') {
                if (c == '\\') {
                        switch ((c = *filename++)) {
                        case '\\':  /* "\\" */
                                continue;
                        case '$':   /* "\$" */
                        case '+':   /* "\+" */
                        case '?':   /* "\?" */
                        case '*':   /* "\*" */
                        case '@':   /* "\@" */
                        case 'x':   /* "\x" */
                        case 'X':   /* "\X" */
                        case 'a':   /* "\a" */
                        case 'A':   /* "\A" */
                        case '-':   /* "\-" */
                                if (pattern_type == -1)
                                        break; /* Must not contain pattern */
                                contains_pattern = true;
                                continue;
                        case '0':   /* "\ooo" */
                        case '1':
                        case '2':
                        case '3':
                                d = *filename++;
                                if (d < '0' || d > '7')
                                        break;
                                e = *filename++;
                                if (e < '0' || e > '7')
                                        break;
                                c = make_byte(c, d, e);
                                if (c && (c <= ' ' || c >= 127))
                                        continue; /* pattern is not \000 */
                        }
                        goto out;
                } else if (c <= ' ' || c >= 127) {
                        goto out;
                }
        }
        if (pattern_type == 1) { /* Must contain pattern */
                if (!contains_pattern)
                        goto out;
        }
        return true;
 out:
        printk(KERN_DEBUG "%s: Invalid pathname '%s'\n", function,
               original_filename);
        return false;
}

/**
 * ccs_is_correct_domain - Check whether the given domainname follows the naming rules.
 * @domainname:   The domainname to check.
 * @function:     The name of function calling me.
 *
 * Returns true if @domainname follows the naming rules, false otherwise.
 */
bool ccs_is_correct_domain(const unsigned char *domainname,
                           const char *function)
{
        unsigned char c;
        unsigned char d;
        unsigned char e;
        const char *org_domainname = domainname;
        if (!domainname || strncmp(domainname, ROOT_NAME, ROOT_NAME_LEN))
                goto out;
        domainname += ROOT_NAME_LEN;
        if (!*domainname)
                return true;
        do {
                if (*domainname++ != ' ')
                        goto out;
                if (*domainname++ != '/')
                        goto out;
                while ((c = *domainname) != '\0' && c != ' ') {
                        domainname++;
                        if (c == '\\') {
                                c = *domainname++;
                                switch ((c)) {
                                case '\\':  /* "\\" */
                                        continue;
                                case '0':   /* "\ooo" */
                                case '1':
                                case '2':
                                case '3':
                                        d = *domainname++;
                                        if (d < '0' || d > '7')
                                                break;
                                        e = *domainname++;
                                        if (e < '0' || e > '7')
                                                break;
                                        c = make_byte(c, d, e);
                                        if (c && (c <= ' ' || c >= 127))
                                                /* pattern is not \000 */
                                                continue;
                                }
                                goto out;
                        } else if (c < ' ' || c >= 127) {
                                goto out;
                        }
                }
        } while (*domainname);
        return true;
 out:
        printk(KERN_DEBUG "%s: Invalid domainname '%s'\n", function,
               org_domainname);
        return false;
}

/**
 * ccs_is_domain_def - Check whether the given token can be a domainname.
 *
 * @buffer: The token to check.
 *
 * Returns true if @buffer possibly be a domainname, false otherwise.
 */
bool ccs_is_domain_def(const unsigned char *buffer)
{
        return !strncmp(buffer, ROOT_NAME, ROOT_NAME_LEN);
}

/**
 * ccs_find_domain - Find a domain by the given name.
 *
 * @domainname: The domainname to find.
 *
 * Returns pointer to "struct domain_info" if found, NULL otherwise.
 */
struct domain_info *ccs_find_domain(const char *domainname)
{
        struct domain_info *domain;
        struct path_info name;
        name.name = domainname;
        ccs_fill_path_info(&name);
        list1_for_each_entry(domain, &domain_list, list) {
                if (!domain->is_deleted &&
                    !ccs_pathcmp(&name, domain->domainname))
                        return domain;
        }
        return NULL;
}

/**
 * path_depth - Evaluate the number of '/' in a string.
 *
 * @pathname: The string to evaluate.
 *
 * Returns path depth of the string.
 *
 * I score 2 for each of the '/' in the @pathname
 * and score 1 if the @pathname ends with '/'.
 */
static int path_depth(const char *pathname)
{
        int i = 0;
        if (pathname) {
                char *ep = strchr(pathname, '\0');
                if (pathname < ep--) {
                        if (*ep != '/')
                                i++;
                        while (pathname <= ep)
                                if (*ep-- == '/')
                                        i += 2;
                }
        }
        return i;
}

/**
 * const_part_length - Evaluate the initial length without a pattern in a token.
 *
 * @filename: The string to evaluate.
 *
 * Returns the initial length without a pattern in @filename.
 */
static int const_part_length(const char *filename)
{
        char c;
        int len = 0;
        if (!filename)
                return 0;
        while ((c = *filename++) != '\0') {
                if (c != '\\') {
                        len++;
                        continue;
                }
                c = *filename++;
                switch (c) {
                case '\\':  /* "\\" */
                        len += 2;
                        continue;
                case '0':   /* "\ooo" */
                case '1':
                case '2':
                case '3':
                        c = *filename++;
                        if (c < '0' || c > '7')
                                break;
                        c = *filename++;
                        if (c < '0' || c > '7')
                                break;
                        len += 4;
                        continue;
                }
                break;
        }
        return len;
}

/**
 * ccs_fill_path_info - Fill in "struct path_info" members.
 *
 * @ptr: Pointer to "struct path_info" to fill in.
 *
 * The caller sets "struct path_info"->name.
 */
void ccs_fill_path_info(struct path_info *ptr)
{
        const char *name = ptr->name;
        const int len = strlen(name);
        ptr->total_len = len;
        ptr->const_len = const_part_length(name);
        ptr->is_dir = len && (name[len - 1] == '/');
        ptr->is_patterned = (ptr->const_len < len);
        ptr->hash = full_name_hash(name, len);
        ptr->depth = path_depth(name);
}

/**
 * file_matches_to_pattern2 - Pattern matching without '/' character
 * and "\-" pattern.
 *
 * @filename:     The start of string to check.
 * @filename_end: The end of string to check.
 * @pattern:      The start of pattern to compare.
 * @pattern_end:  The end of pattern to compare.
 *
 * Returns true if @filename matches @pattern, false otherwise.
 */
static bool file_matches_to_pattern2(const char *filename,
                                     const char *filename_end,
                                     const char *pattern,
                                     const char *pattern_end)
{
        while (filename < filename_end && pattern < pattern_end) {
                char c;
                if (*pattern != '\\') {
                        if (*filename++ != *pattern++)
                                return false;
                        continue;
                }
                c = *filename;
                pattern++;
                switch (*pattern) {
                        int i;
                        int j;
                case '?':
                        if (c == '/') {
                                return false;
                        } else if (c == '\\') {
                                if (filename[1] == '\\')
                                        filename++;
                                else if (is_byte_range(filename + 1))
                                        filename += 3;
                                else
                                        return false;
                        }
                        break;
                case '\\':
                        if (c != '\\')
                                return false;
                        if (*++filename != '\\')
                                return false;
                        break;
                case '+':
                        if (!is_decimal(c))
                                return false;
                        break;
                case 'x':
                        if (!is_hexadecimal(c))
                                return false;
                        break;
                case 'a':
                        if (!is_alphabet_char(c))
                                return false;
                        break;
                case '0':
                case '1':
                case '2':
                case '3':
                        if (c == '\\' && is_byte_range(filename + 1)
                            && strncmp(filename + 1, pattern, 3) == 0) {
                                filename += 3;
                                pattern += 2;
                                break;
                        }
                        return false; /* Not matched. */
                case '*':
                case '@':
                        for (i = 0; i <= filename_end - filename; i++) {
                                if (file_matches_to_pattern2(filename + i,
                                                             filename_end,
                                                             pattern + 1,
                                                             pattern_end))
                                        return true;
                                c = filename[i];
                                if (c == '.' && *pattern == '@')
                                        break;
                                if (c != '\\')
                                        continue;
                                if (filename[i + 1] == '\\')
                                        i++;
                                else if (is_byte_range(filename + i + 1))
                                        i += 3;
                                else
                                        break; /* Bad pattern. */
                        }
                        return false; /* Not matched. */
                default:
                        j = 0;
                        c = *pattern;
                        if (c == '$') {
                                while (is_decimal(filename[j]))
                                        j++;
                        } else if (c == 'X') {
                                while (is_hexadecimal(filename[j]))
                                        j++;
                        } else if (c == 'A') {
                                while (is_alphabet_char(filename[j]))
                                        j++;
                        }
                        for (i = 1; i <= j; i++) {
                                if (file_matches_to_pattern2(filename + i,
                                                             filename_end,
                                                             pattern + 1,
                                                             pattern_end))
                                        return true;
                        }
                        return false; /* Not matched or bad pattern. */
                }
                filename++;
                pattern++;
        }
        while (*pattern == '\\' &&
               (*(pattern + 1) == '*' || *(pattern + 1) == '@'))
                pattern += 2;
        return filename == filename_end && pattern == pattern_end;
}

/**
 * file_matches_to_pattern - Pattern matching without without '/' character.
 *
 * @filename:     The start of string to check.
 * @filename_end: The end of string to check.
 * @pattern:      The start of pattern to compare.
 * @pattern_end:  The end of pattern to compare.
 *
 * Returns true if @filename matches @pattern, false otherwise.
 */
static bool file_matches_to_pattern(const char *filename,
                                    const char *filename_end,
                                    const char *pattern,
                                    const char *pattern_end)
{
        const char *pattern_start = pattern;
        bool first = true;
        bool result;
        while (pattern < pattern_end - 1) {
                /* Split at "\-" pattern. */
                if (*pattern++ != '\\' || *pattern++ != '-')
                        continue;
                result = file_matches_to_pattern2(filename, filename_end,
                                                  pattern_start, pattern - 2);
                if (first)
                        result = !result;
                if (result)
                        return false;
                first = false;
                pattern_start = pattern;
        }
        result = file_matches_to_pattern2(filename, filename_end,
                                          pattern_start, pattern_end);
        return first ? result : !result;
}

/**
 * ccs_path_matches_pattern - Check whether the given filename matches the given pattern.
 * @filename: The filename to check.
 * @pattern:  The pattern to compare.
 *
 * Returns true if matches, false otherwise.
 *
 * The following patterns are available.
 *   \\     \ itself.
 *   \ooo   Octal representation of a byte.
 *   \*     More than or equals to 0 character other than '/'.
 *   \@     More than or equals to 0 character other than '/' or '.'.
 *   \?     1 byte character other than '/'.
 *   \$     More than or equals to 1 decimal digit.
 *   \+     1 decimal digit.
 *   \X     More than or equals to 1 hexadecimal digit.
 *   \x     1 hexadecimal digit.
 *   \A     More than or equals to 1 alphabet character.
 *   \a     1 alphabet character.
 *   \-     Subtraction operator.
 */
bool ccs_path_matches_pattern(const struct path_info *filename,
                              const struct path_info *pattern)
{
        /*
          if (!filename || !pattern)
          return false;
        */
        const char *f = filename->name;
        const char *p = pattern->name;
        const int len = pattern->const_len;
        /* If @pattern doesn't contain pattern, I can use strcmp(). */
        if (!pattern->is_patterned)
                return !ccs_pathcmp(filename, pattern);
        /* Dont compare if the number of '/' differs. */
        if (filename->depth != pattern->depth)
                return false;
        /* Compare the initial length without patterns. */
        if (strncmp(f, p, len))
                return false;
        f += len;
        p += len;
        /* Main loop. Compare each directory component. */
        while (*f && *p) {
                const char *f_delimiter = strchr(f, '/');
                const char *p_delimiter = strchr(p, '/');
                if (!f_delimiter)
                        f_delimiter = strchr(f, '\0');
                if (!p_delimiter)
                        p_delimiter = strchr(p, '\0');
                if (!file_matches_to_pattern(f, f_delimiter, p, p_delimiter))
                        return false;
                f = f_delimiter;
                if (*f)
                        f++;
                p = p_delimiter;
                if (*p)
                        p++;
        }
        /* Ignore trailing "\*" and "\@" in @pattern. */
        while (*p == '\\' &&
               (*(p + 1) == '*' || *(p + 1) == '@'))
                p += 2;
        return !*f && !*p;
}

/**
 * ccs_io_printf - Transactional printf() to "struct ccs_io_buffer" structure.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @fmt:  The printf()'s format string, followed by parameters.
 *
 * Returns true on success, false otherwise.
 *
 * The snprintf() will truncate, but ccs_io_printf() won't.
 */
bool ccs_io_printf(struct ccs_io_buffer *head, const char *fmt, ...)
{
        va_list args;
        int len;
        int pos = head->read_avail;
        int size = head->readbuf_size - pos;
        if (size <= 0)
                return false;
        va_start(args, fmt);
        len = vsnprintf(head->read_buf + pos, size, fmt, args);
        va_end(args);
        if (pos + len >= head->readbuf_size)
                return false;
        head->read_avail += len;
        return true;
}

/**
 * ccs_get_exe - Get ccs_realpath() of current process.
 *
 * Returns the ccs_realpath() of current process on success, NULL otherwise.
 *
 * This function uses ccs_alloc(), so the caller must ccs_free()
 * if this function didn't return NULL.
 */
const char *ccs_get_exe(void)
{
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma;
        const char *cp = NULL;
        if (!mm)
                return NULL;
        down_read(&mm->mmap_sem);
        for (vma = mm->mmap; vma; vma = vma->vm_next) {
                if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
                        cp = ccs_realpath_from_dentry(vma->vm_file->f_dentry,
                                                      vma->vm_file->f_vfsmnt);
                        break;
                }
        }
        up_read(&mm->mmap_sem);
        return cp;
}

/**
 * ccs_get_msg - Get warning message.
 *
 * @is_enforce: Is it enforcing mode?
 *
 * Returns "ERROR" or "WARNING".
 */
const char *ccs_get_msg(const bool is_enforce)
{
        if (is_enforce)
                return "ERROR";
        else
                return "WARNING";
}

/**
 * ccs_check_flags_no_sleep_check - Check mode for specified functionality.
 *
 * @index: The functionality to check mode.
 *
 * Returns the mode of specified functionality.
 */
unsigned int ccs_check_flags_no_sleep_check(const u8 index)
{
        const u8 profile = current->domain_info->profile;
        return sbin_init_started && index < CCS_MAX_CONTROL_INDEX
#if MAX_PROFILES != 256
                && profile < MAX_PROFILES
#endif
                && profile_ptr[profile] ?
                profile_ptr[profile]->value[index] : 0;
}

/**
 * sleep_check - Check whether it is permitted to do operations that may sleep.
 *
 * Returns true if it is permitted to do operations that may sleep,
 * false otherwise.
 *
 * TOMOYO Linux supports interactive enforcement that lets processes
 * wait for the administrator's decision.
 * All hooks but the one for ccs_may_autobind() are inserted where
 * it is permitted to do operations that may sleep.
 * Thus, this warning should not happen.
 */
static bool sleep_check(void)
{
        static u8 count = 20;
        if (likely(!in_interrupt()))
                return true;
        if (count) {
                count--;
                printk(KERN_ERR "BUG: sleeping function called "
                       "from invalid context.\n");
                dump_stack();
        }
        return false;
}

/**
 * ccs_check_flags - Check mode for specified functionality.
 *
 * @index: The functionality to check mode.
 *
 * Returns the mode of specified functionality.
 */
unsigned int ccs_check_flags(const u8 index)
{
        return sleep_check() ? ccs_check_flags_no_sleep_check(index) : 0;
}

#ifdef CONFIG_TOMOYO
/**
 * ccs_check_capability_flags - Check mode for specified capability.
 *
 * @index: The capability to check mode.
 *
 * Returns the mode of specified capability.
 */
u8 ccs_check_capability_flags(const u8 index)
{
        const u8 profile = current->domain_info->profile;
        return sbin_init_started && index < TOMOYO_MAX_CAPABILITY_INDEX
#if MAX_PROFILES != 256
                && profile < MAX_PROFILES
#endif
                && sleep_check()
                && profile_ptr[profile] ?
                profile_ptr[profile]->capability_value[index] : 0;
}

/**
 * ccs_cap2keyword - Convert capability operation to capability name.
 *
 * @operation: The capability index.
 *
 * Returns the name of the specified capability's name.
 */
const char *ccs_cap2keyword(const u8 operation)
{
        return operation < TOMOYO_MAX_CAPABILITY_INDEX
                ? capability_control_keyword[operation] : NULL;
}

#endif

/**
 * ccs_verbose_mode - Check whether TOMOYO is verbose mode.
 *
 * Returns true if domain policy violation warning should be printed to
 * console.
 */
bool ccs_verbose_mode(void)
{
        return ccs_check_flags(CCS_TOMOYO_VERBOSE) != 0;
}

/**
 * ccs_check_domain_quota - Check for domain's quota.
 *
 * @domain: Pointer to "struct domain_info".
 *
 * Returns true if the domain is not exceeded quota, false otherwise.
 */
bool ccs_check_domain_quota(struct domain_info * const domain)
{
        unsigned int count = 0;
        struct acl_info *ptr;
        if (!domain)
                return true;
        list1_for_each_entry(ptr, &domain->acl_info_list, list) {
                if (ptr->type & ACL_DELETED)
                        continue;
                switch (ccs_acl_type2(ptr)) {
                        struct single_path_acl_record *acl1;
                        struct double_path_acl_record *acl2;
                        u16 perm;
                case TYPE_SINGLE_PATH_ACL:
                        acl1 = container_of(ptr, struct single_path_acl_record,
                                            head);
                        perm = acl1->perm;
                        if (perm & (1 << TYPE_EXECUTE_ACL))
                                count++;
                        if (perm &
                            ((1 << TYPE_READ_ACL) | (1 << TYPE_WRITE_ACL)))
                                count++;
                        if (perm & (1 << TYPE_CREATE_ACL))
                                count++;
                        if (perm & (1 << TYPE_UNLINK_ACL))
                                count++;
                        if (perm & (1 << TYPE_MKDIR_ACL))
                                count++;
                        if (perm & (1 << TYPE_RMDIR_ACL))
                                count++;
                        if (perm & (1 << TYPE_MKFIFO_ACL))
                                count++;
                        if (perm & (1 << TYPE_MKSOCK_ACL))
                                count++;
                        if (perm & (1 << TYPE_MKBLOCK_ACL))
                                count++;
                        if (perm & (1 << TYPE_MKCHAR_ACL))
                                count++;
                        if (perm & (1 << TYPE_TRUNCATE_ACL))
                                count++;
                        if (perm & (1 << TYPE_SYMLINK_ACL))
                                count++;
                        if (perm & (1 << TYPE_REWRITE_ACL))
                                count++;
                        break;
                case TYPE_DOUBLE_PATH_ACL:
                        acl2 = container_of(ptr, struct double_path_acl_record,
                                            head);
                        perm = acl2->perm;
                        if (perm & (1 << TYPE_LINK_ACL))
                                count++;
                        if (perm & (1 << TYPE_RENAME_ACL))
                                count++;
                        break;
                case TYPE_EXECUTE_HANDLER:
                case TYPE_DENIED_EXECUTE_HANDLER:
                        break;
                default:
                        count++;
                }
        }
        if (count < ccs_check_flags(CCS_TOMOYO_MAX_ACCEPT_ENTRY))
                return true;
        if (!domain->quota_warned) {
                domain->quota_warned = true;
                printk(KERN_WARNING "TOMOYO-WARNING: "
                       "Domain '%s' has so many ACLs to hold. "
                       "Stopped learning mode.\n", domain->domainname->name);
        }
        return false;
}

/**
 * ccs_find_or_assign_new_profile - Create a new profile.
 *
 * @profile: Profile number to create.
 *
 * Returns pointer to "struct profile" on success, NULL otherwise.
 */
static struct profile *ccs_find_or_assign_new_profile(const unsigned int
                                                      profile)
{
        static DEFINE_MUTEX(profile_lock);
        struct profile *ptr = NULL;
        mutex_lock(&profile_lock);
        if (profile < MAX_PROFILES) {
                ptr = profile_ptr[profile];
                if (ptr)
                        goto ok;
                ptr = ccs_alloc_element(sizeof(*ptr));
                if (ptr) {
                        int i;
                        for (i = 0; i < CCS_MAX_CONTROL_INDEX; i++)
                                ptr->value[i]
                                        = ccs_control_array[i].current_value;
                        /*
                         * Needn't to initialize "ptr->capability_value"
                         * because they are always 0.
                         */
                        mb(); /* Avoid out-of-order execution. */
                        profile_ptr[profile] = ptr;
                }
        }
 ok:
        mutex_unlock(&profile_lock);
        return ptr;
}

/**
 * write_profile - Write profile table.
 *
 * @head: Pointer to "struct ccs_io_buffer"
 *
 * Returns 0 on success, negative value otherwise.
 */
static int write_profile(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        unsigned int i;
        unsigned int value;
        char *cp;
        struct profile *profile;
        i = simple_strtoul(data, &cp, 10);
        if (data != cp) {
                if (*cp != '-')
                        return -EINVAL;
                data = cp + 1;
        }
        profile = ccs_find_or_assign_new_profile(i);
        if (!profile)
                return -EINVAL;
        cp = strchr(data, '=');
        if (!cp)
                return -EINVAL;
        *cp = '\0';
        ccs_update_counter(CCS_UPDATES_COUNTER_PROFILE);
        if (!strcmp(data, "COMMENT")) {
                profile->comment = ccs_save_name(cp + 1);
                return 0;
        }
#ifdef CONFIG_TOMOYO
        if (str_starts(&data, KEYWORD_MAC_FOR_CAPABILITY)) {
                if (sscanf(cp + 1, "%u", &value) != 1) {
                        for (i = 0; i < 4; i++) {
                                if (strcmp(cp + 1, mode_4[i]))
                                        continue;
                                value = i;
                                break;
                        }
                        if (i == 4)
                                return -EINVAL;
                }
                if (value > 3)
                        value = 3;
                for (i = 0; i < TOMOYO_MAX_CAPABILITY_INDEX; i++) {
                        if (strcmp(data, capability_control_keyword[i]))
                                continue;
                        profile->capability_value[i] = value;
                        return 0;
                }
                return -EINVAL;
        }
#endif
        for (i = 0; i < CCS_MAX_CONTROL_INDEX; i++) {
                if (strcmp(data, ccs_control_array[i].keyword))
                        continue;
                if (sscanf(cp + 1, "%u", &value) != 1) {
                        int j;
                        const char **modes;
                        switch (i) {
                        case CCS_SAKURA_RESTRICT_AUTOBIND:
                        case CCS_TOMOYO_VERBOSE:
                                modes = mode_2;
                                break;
                        default:
                                modes = mode_4;
                                break;
                        }
                        for (j = 0; j < 4; j++) {
                                if (strcmp(cp + 1, modes[j]))
                                        continue;
                                value = j;
                                break;
                        }
                        if (j == 4)
                                return -EINVAL;
                } else if (value > ccs_control_array[i].max_value) {
                        value = ccs_control_array[i].max_value;
                }
                switch (i) {
                case CCS_SAKURA_DENY_CONCEAL_MOUNT:
                case CCS_SAKURA_RESTRICT_UNMOUNT:
                        if (value == 1)
                                value = 2; /* learning mode is not supported. */
                }
                profile->value[i] = value;
                return 0;
        }
        return -EINVAL;
}

/**
 * read_profile - Read profile table.
 *
 * @head: Pointer to "struct ccs_io_buffer"
 *
 * Returns 0.
 */
static int read_profile(struct ccs_io_buffer *head)
{
        static const int total
                = CCS_MAX_CONTROL_INDEX + TOMOYO_MAX_CAPABILITY_INDEX + 1;
        int step;
        if (head->read_eof)
                return 0;
        for (step = head->read_step; step < MAX_PROFILES * total; step++) {
                const u8 index = step / total;
                u8 type = step % total;
                const struct profile *profile = profile_ptr[index];
                head->read_step = step;
                if (!profile)
                        continue;
#if !defined(CONFIG_SAKURA) || !defined(CONFIG_TOMOYO)
                switch (type) {
#ifndef CONFIG_SAKURA
                case CCS_SAKURA_DENY_CONCEAL_MOUNT:
                case CCS_SAKURA_RESTRICT_CHROOT:
                case CCS_SAKURA_RESTRICT_MOUNT:
                case CCS_SAKURA_RESTRICT_UNMOUNT:
                case CCS_SAKURA_RESTRICT_PIVOT_ROOT:
                case CCS_SAKURA_RESTRICT_AUTOBIND:
#endif
#ifndef CONFIG_TOMOYO
                case CCS_TOMOYO_MAC_FOR_FILE:
                case CCS_TOMOYO_MAC_FOR_ARGV0:
                case CCS_TOMOYO_MAC_FOR_ENV:
                case CCS_TOMOYO_MAC_FOR_NETWORK:
                case CCS_TOMOYO_MAC_FOR_SIGNAL:
                case CCS_TOMOYO_MAX_ACCEPT_ENTRY:
                case CCS_TOMOYO_MAX_GRANT_LOG:
                case CCS_TOMOYO_MAX_REJECT_LOG:
                case CCS_TOMOYO_VERBOSE:
#endif
                        continue;
                }
#endif
                if (!type) { /* Print profile' comment tag. */
                        if (!ccs_io_printf(head, "%u-COMMENT=%s\n",
                                           index, profile->comment ?
                                           profile->comment->name : ""))
                                break;
                        continue;
                }
                type--;
                if (type >= CCS_MAX_CONTROL_INDEX) {
#ifdef CONFIG_TOMOYO
                        const int i = type - CCS_MAX_CONTROL_INDEX;
                        const u8 value = profile->capability_value[i];
                        if (!ccs_io_printf(head,
                                           "%u-" KEYWORD_MAC_FOR_CAPABILITY
                                           "%s=%s\n", index,
                                           capability_control_keyword[i],
                                           mode_4[value]))
                                break;
#endif
                } else {
                        const unsigned int value = profile->value[type];
                        const char **modes = NULL;
                        const char *keyword = ccs_control_array[type].keyword;
                        switch (ccs_control_array[type].max_value) {
                        case 3:
                                modes = mode_4;
                                break;
                        case 1:
                                modes = mode_2;
                                break;
                        }
                        if (modes) {
                                if (!ccs_io_printf(head, "%u-%s=%s\n", index,
                                                   keyword, modes[value]))
                                        break;
                        } else {
                                if (!ccs_io_printf(head, "%u-%s=%u\n", index,
                                                   keyword, value))
                                        break;
                        }
                }
        }
        if (step == MAX_PROFILES * total)
                head->read_eof = true;
        return 0;
}

/* Structure for policy manager. */
struct policy_manager_entry {
        struct list1_head list;
        /* A path to program or a domainname. */
        const struct path_info *manager;
        bool is_domain;  /* True if manager is a domainname. */
        bool is_deleted; /* True if this entry is deleted. */
};

/* The list for "struct policy_manager_entry". */
static LIST1_HEAD(policy_manager_list);

/**
 * update_manager_entry - Add a manager entry.
 *
 * @manager:   The path to manager or the domainnamme.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int update_manager_entry(const char *manager, const bool is_delete)
{
        struct policy_manager_entry *new_entry;
        struct policy_manager_entry *ptr;
        static DEFINE_MUTEX(lock);
        const struct path_info *saved_manager;
        int error = -ENOMEM;
        bool is_domain = false;
        if (ccs_is_domain_def(manager)) {
                if (!ccs_is_correct_domain(manager, __func__))
                        return -EINVAL;
                is_domain = true;
        } else {
                if (!ccs_is_correct_path(manager, 1, -1, -1, __func__))
                        return -EINVAL;
        }
        saved_manager = ccs_save_name(manager);
        if (!saved_manager)
                return -ENOMEM;
        mutex_lock(&lock);
        list1_for_each_entry(ptr, &policy_manager_list, list) {
                if (ptr->manager != saved_manager)
                        continue;
                ptr->is_deleted = is_delete;
                error = 0;
                goto out;
        }
        if (is_delete) {
                error = -ENOENT;
                goto out;
        }
        new_entry = ccs_alloc_element(sizeof(*new_entry));
        if (!new_entry)
                goto out;
        new_entry->manager = saved_manager;
        new_entry->is_domain = is_domain;
        list1_add_tail_mb(&new_entry->list, &policy_manager_list);
        error = 0;
 out:
        mutex_unlock(&lock);
        if (!error)
                ccs_update_counter(CCS_UPDATES_COUNTER_MANAGER);
        return error;
}

/**
 * write_manager_policy - Write manager policy.
 *
 * @head: Pointer to "struct ccs_io_buffer"
 *
 * Returns 0 on success, negative value otherwise.
 */
static int write_manager_policy(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        bool is_delete = str_starts(&data, KEYWORD_DELETE);
        if (!strcmp(data, "manage_by_non_root")) {
                manage_by_non_root = !is_delete;
                return 0;
        }
        return update_manager_entry(data, is_delete);
}

/**
 * read_manager_policy - Read manager policy.
 *
 * @head: Pointer to "struct ccs_io_buffer"
 *
 * Returns 0.
 */
static int read_manager_policy(struct ccs_io_buffer *head)
{
        struct list1_head *pos;
        if (head->read_eof)
                return 0;
        list1_for_each_cookie(pos, head->read_var2, &policy_manager_list) {
                struct policy_manager_entry *ptr;
                ptr = list1_entry(pos, struct policy_manager_entry, list);
                if (ptr->is_deleted)
                        continue;
                if (!ccs_io_printf(head, "%s\n", ptr->manager->name))
                        return 0;
        }
        head->read_eof = true;
        return 0;
}

/**
 * is_policy_manager - Check whether the current process is a policy manager.
 *
 * Returns true if the current process is permitted to modify policy
 * via /proc/ccs/ interface.
 */
static bool is_policy_manager(void)
{
        struct policy_manager_entry *ptr;
        const char *exe;
        struct task_struct *task = current;
        const struct path_info *domainname = task->domain_info->domainname;
        bool found = false;
        if (!sbin_init_started)
                return true;
        if (task->tomoyo_flags & CCS_TASK_IS_POLICY_MANAGER)
                return true;
        if (!manage_by_non_root && (task->uid || task->euid))
                return false;
        list1_for_each_entry(ptr, &policy_manager_list, list) {
                if (!ptr->is_deleted && ptr->is_domain
                    && !ccs_pathcmp(domainname, ptr->manager)) {
                        /* Set manager flag. */
                        task->tomoyo_flags |= CCS_TASK_IS_POLICY_MANAGER;
                        return true;
                }
        }
        exe = ccs_get_exe();
        if (!exe)
                return false;
        list1_for_each_entry(ptr, &policy_manager_list, list) {
                if (!ptr->is_deleted && !ptr->is_domain
                    && !strcmp(exe, ptr->manager->name)) {
                        found = true;
                        /* Set manager flag. */
                        task->tomoyo_flags |= CCS_TASK_IS_POLICY_MANAGER;
                        break;
                }
        }
        if (!found) { /* Reduce error messages. */
                static pid_t last_pid;
                const pid_t pid = current->pid;
                if (last_pid != pid) {
                        printk(KERN_WARNING "%s ( %s ) is not permitted to "
                               "update policies.\n", domainname->name, exe);
                        last_pid = pid;
                }
        }
        ccs_free(exe);
        return found;
}

#ifdef CONFIG_TOMOYO

/**
 * ccs_find_condition_part - Find condition part from the statement.
 *
 * @data: String to parse.
 *
 * Returns pointer to the condition part if it was found in the statement,
 * NULL otherwise.
 */
static char *ccs_find_condition_part(char *data)
{
        char *cp = strstr(data, " if ");
        if (cp) {
                char *cp2;
                while ((cp2 = strstr(cp + 3, " if ")) != NULL)
                        cp = cp2;
                *cp++ = '\0';
        } else {
                cp = strstr(data, " ; set ");
                if (cp)
                        *cp++ = '\0';
        }
        return cp;
}

/**
 * write_domain_policy - Write domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int write_domain_policy(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        struct domain_info *domain = head->write_var1;
        bool is_delete = false;
        bool is_select = false;
        bool is_undelete = false;
        unsigned int profile;
        const struct condition_list *cond = NULL;
        char *cp;
        if (str_starts(&data, KEYWORD_DELETE))
                is_delete = true;
        else if (str_starts(&data, KEYWORD_SELECT))
                is_select = true;
        else if (str_starts(&data, KEYWORD_UNDELETE))
                is_undelete = true;
        if (ccs_is_domain_def(data)) {
                domain = NULL;
                if (is_delete)
                        ccs_delete_domain(data);
                else if (is_select)
                        domain = ccs_find_domain(data);
                else if (is_undelete)
                        domain = ccs_undelete_domain(data);
                else
                        domain = ccs_find_or_assign_new_domain(data, 0);
                head->write_var1 = domain;
                ccs_update_counter(CCS_UPDATES_COUNTER_DOMAIN_POLICY);
                return 0;
        }
        if (!domain)
                return -EINVAL;

        if (sscanf(data, KEYWORD_USE_PROFILE "%u", &profile) == 1
            && profile < MAX_PROFILES) {
                if (profile_ptr[profile] || !sbin_init_started)
                        domain->profile = (u8) profile;
                return 0;
        }
        if (!strcmp(data, KEYWORD_IGNORE_GLOBAL_ALLOW_READ)) {
                ccs_set_domain_flag(domain, is_delete,
                                    DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_READ);
                return 0;
        }
        if (!strcmp(data, KEYWORD_IGNORE_GLOBAL_ALLOW_ENV)) {
                ccs_set_domain_flag(domain, is_delete,
                                    DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_ENV);
                return 0;
        }
        cp = ccs_find_condition_part(data);
        if (cp) {
                cond = ccs_find_or_assign_new_condition(cp);
                if (!cond)
                        return -EINVAL;
        }
        if (str_starts(&data, KEYWORD_ALLOW_CAPABILITY))
                return ccs_write_capability_policy(data, domain, cond,
                                                   is_delete);
        else if (str_starts(&data, KEYWORD_ALLOW_NETWORK))
                return ccs_write_network_policy(data, domain, cond, is_delete);
        else if (str_starts(&data, KEYWORD_ALLOW_SIGNAL))
                return ccs_write_signal_policy(data, domain, cond, is_delete);
        else if (str_starts(&data, KEYWORD_ALLOW_ARGV0))
                return ccs_write_argv0_policy(data, domain, cond, is_delete);
        else if (str_starts(&data, KEYWORD_ALLOW_ENV))
                return ccs_write_env_policy(data, domain, cond, is_delete);
        else
                return ccs_write_file_policy(data, domain, cond, is_delete);
}

/**
 * print_single_path_acl - Print a single path ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct single_path_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_single_path_acl(struct ccs_io_buffer *head,
                                  struct single_path_acl_record *ptr,
                                  const struct condition_list *cond)
{
        int pos;
        u8 bit;
        const char *atmark = "";
        const char *filename;
        const u16 perm = ptr->perm;
        if (ptr->u_is_group) {
                atmark = "@";
                filename = ptr->u.group->group_name->name;
        } else {
                filename = ptr->u.filename->name;
        }
        for (bit = head->read_bit; bit < MAX_SINGLE_PATH_OPERATION; bit++) {
                const char *msg;
                if (!(perm & (1 << bit)))
                        continue;
                /* Print "read/write" instead of "read" and "write". */
                if ((bit == TYPE_READ_ACL || bit == TYPE_WRITE_ACL)
                    && (perm & (1 << TYPE_READ_WRITE_ACL)))
                        continue;
                msg = ccs_sp2keyword(bit);
                pos = head->read_avail;
                if (!ccs_io_printf(head, "allow_%s %s%s", msg,
                                   atmark, filename) ||
                    !ccs_print_condition(head, cond))
                        goto out;
        }
        head->read_bit = 0;
        return true;
 out:
        head->read_bit = bit;
        head->read_avail = pos;
        return false;
}

/**
 * print_double_path_acl - Print a double path ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct double_path_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_double_path_acl(struct ccs_io_buffer *head,
                                  struct double_path_acl_record *ptr,
                                  const struct condition_list *cond)
{
        int pos;
        const char *atmark1 = "";
        const char *atmark2 = "";
        const char *filename1;
        const char *filename2;
        const u8 perm = ptr->perm;
        u8 bit;
        if (ptr->u1_is_group) {
                atmark1 = "@";
                filename1 = ptr->u1.group1->group_name->name;
        } else {
                filename1 = ptr->u1.filename1->name;
        }
        if (ptr->u2_is_group) {
                atmark2 = "@";
                filename2 = ptr->u2.group2->group_name->name;
        } else {
                filename2 = ptr->u2.filename2->name;
        }
        for (bit = head->read_bit; bit < MAX_DOUBLE_PATH_OPERATION; bit++) {
                const char *msg;
                if (!(perm & (1 << bit)))
                        continue;
                msg = ccs_dp2keyword(bit);
                pos = head->read_avail;
                if (!ccs_io_printf(head, "allow_%s %s%s %s%s", msg,
                                   atmark1, filename1, atmark2, filename2) ||
                    !ccs_print_condition(head, cond))
                        goto out;
        }
        head->read_bit = 0;
        return true;
 out:
        head->read_bit = bit;
        head->read_avail = pos;
        return false;
}

/**
 * print_argv0_acl - Print an argv[0] ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct argv0_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_argv0_acl(struct ccs_io_buffer *head,
                            struct argv0_acl_record *ptr,
                            const struct condition_list *cond)
{
        int pos = head->read_avail;
        if (!ccs_io_printf(head, KEYWORD_ALLOW_ARGV0 "%s %s",
                           ptr->filename->name, ptr->argv0->name))
                goto out;
        if (!ccs_print_condition(head, cond))
                goto out;
        return true;
 out:
        head->read_avail = pos;
        return false;
}

/**
 * print_env_acl - Print an evironment variable name's ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct env_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_env_acl(struct ccs_io_buffer *head,
                          struct env_acl_record *ptr,
                          const struct condition_list *cond)
{
        int pos = head->read_avail;
        if (!ccs_io_printf(head, KEYWORD_ALLOW_ENV "%s", ptr->env->name))
                goto out;
        if (!ccs_print_condition(head, cond))
                goto out;
        return true;
 out:
        head->read_avail = pos;
        return false;
}

/**
 * print_capability_acl - Print a capability ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct capability_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_capability_acl(struct ccs_io_buffer *head,
                                 struct capability_acl_record *ptr,
                                 const struct condition_list *cond)
{
        int pos = head->read_avail;
        if (!ccs_io_printf(head, KEYWORD_ALLOW_CAPABILITY "%s",
                           ccs_cap2keyword(ptr->operation)))
                goto out;
        if (!ccs_print_condition(head, cond))
                goto out;
        return true;
 out:
        head->read_avail = pos;
        return false;
}

/**
 * print_ipv4_entry - Print IPv4 address of a network ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ip_network_acl_record".
 *
 * Returns true on success, false otherwise.
 */
static bool print_ipv4_entry(struct ccs_io_buffer *head,
                             struct ip_network_acl_record *ptr)
{
        const u32 min_address = ptr->u.ipv4.min;
        const u32 max_address = ptr->u.ipv4.max;
        if (!ccs_io_printf(head, "%u.%u.%u.%u", HIPQUAD(min_address)))
                return false;
        if (min_address != max_address
            && !ccs_io_printf(head, "-%u.%u.%u.%u", HIPQUAD(max_address)))
                return false;
        return true;
}

/**
 * print_ipv6_entry - Print IPv6 address of a network ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ip_network_acl_record".
 *
 * Returns true on success, false otherwise.
 */
static bool print_ipv6_entry(struct ccs_io_buffer *head,
                             struct ip_network_acl_record *ptr)
{
        char buf[64];
        const struct in6_addr *min_address = ptr->u.ipv6.min;
        const struct in6_addr *max_address = ptr->u.ipv6.max;
        ccs_print_ipv6(buf, sizeof(buf), min_address);
        if (!ccs_io_printf(head, "%s", buf))
                return false;
        if (min_address != max_address) {
                ccs_print_ipv6(buf, sizeof(buf), max_address);
                if (!ccs_io_printf(head, "-%s", buf))
                        return false;
        }
        return true;
}

/**
 * print_port_entry - Print port number of a network ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ip_network_acl_record".
 *
 * Returns true on success, false otherwise.
 */
static bool print_port_entry(struct ccs_io_buffer *head,
                             struct ip_network_acl_record *ptr)
{
        const u16 min_port = ptr->min_port, max_port = ptr->max_port;
        if (!ccs_io_printf(head, " %u", min_port))
                return false;
        if (min_port != max_port && !ccs_io_printf(head, "-%u", max_port))
                return false;
        return true;
}

/**
 * print_network_acl - Print a network ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ip_network_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_network_acl(struct ccs_io_buffer *head,
                              struct ip_network_acl_record *ptr,
                              const struct condition_list *cond)
{
        int pos = head->read_avail;
        if (!ccs_io_printf(head, KEYWORD_ALLOW_NETWORK "%s ",
                           ccs_net2keyword(ptr->operation_type)))
                goto out;
        switch (ptr->record_type) {
        case IP_RECORD_TYPE_ADDRESS_GROUP:
                if (!ccs_io_printf(head, "@%s", ptr->u.group->group_name->name))
                        goto out;
                break;
        case IP_RECORD_TYPE_IPv4:
                if (!print_ipv4_entry(head, ptr))
                        goto out;
                break;
        case IP_RECORD_TYPE_IPv6:
                if (!print_ipv6_entry(head, ptr))
                        goto out;
                break;
        }
        if (!print_port_entry(head, ptr))
                goto out;
        if (!ccs_print_condition(head, cond))
                goto out;
        return true;
 out:
        head->read_avail = pos;
        return false;
}

/**
 * print_signal_acl - Print a signal ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct signale_acl_record".
 * @cond: Pointer to "struct condition_list". May be NULL.
 *
 * Returns true on success, false otherwise.
 */
static bool print_signal_acl(struct ccs_io_buffer *head,
                             struct signal_acl_record *ptr,
                             const struct condition_list *cond)
{
        int pos = head->read_avail;
        if (!ccs_io_printf(head, KEYWORD_ALLOW_SIGNAL "%u %s",
                           ptr->sig, ptr->domainname->name))
                goto out;
        if (!ccs_print_condition(head, cond))
                goto out;
        return true;
 out:
        head->read_avail = pos;
        return false;
}

/**
 * print_execute_handler_record - Print an execute handler ACL entry.
 *
 * @head:    Pointer to "struct ccs_io_buffer".
 * @keyword: Name of the keyword.
 * @ptr:     Pointer to "struct execute_handler_record".
 *
 * Returns true on success, false otherwise.
 */
static bool print_execute_handler_record(struct ccs_io_buffer *head,
                                         const char *keyword,
                                         struct execute_handler_record *ptr)
{
        return ccs_io_printf(head, "%s %s\n", keyword, ptr->handler->name);
}

/**
 * print_entry - Print an ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to an ACL entry.
 *
 * Returns true on success, false otherwise.
 */
static bool print_entry(struct ccs_io_buffer *head, struct acl_info *ptr)
{
        const struct condition_list *cond = ccs_get_condition_part(ptr);
        const u8 acl_type = ccs_acl_type2(ptr);
        if (acl_type & ACL_DELETED)
                return true;
        if (acl_type == TYPE_SINGLE_PATH_ACL) {
                struct single_path_acl_record *acl
                        = container_of(ptr, struct single_path_acl_record,
                                       head);
                return print_single_path_acl(head, acl, cond);
        }
        if (acl_type == TYPE_DOUBLE_PATH_ACL) {
                struct double_path_acl_record *acl
                        = container_of(ptr, struct double_path_acl_record,
                                       head);
                return print_double_path_acl(head, acl, cond);
        }
        if (acl_type == TYPE_ARGV0_ACL) {
                struct argv0_acl_record *acl
                        = container_of(ptr, struct argv0_acl_record, head);
                return print_argv0_acl(head, acl, cond);
        }
        if (acl_type == TYPE_ENV_ACL) {
                struct env_acl_record *acl
                        = container_of(ptr, struct env_acl_record, head);
                return print_env_acl(head, acl, cond);
        }
        if (acl_type == TYPE_CAPABILITY_ACL) {
                struct capability_acl_record *acl
                        = container_of(ptr, struct capability_acl_record, head);
                return print_capability_acl(head, acl, cond);
        }
        if (acl_type == TYPE_IP_NETWORK_ACL) {
                struct ip_network_acl_record *acl
                        = container_of(ptr, struct ip_network_acl_record, head);
                return print_network_acl(head, acl, cond);
        }
        if (acl_type == TYPE_SIGNAL_ACL) {
                struct signal_acl_record *acl
                        = container_of(ptr, struct signal_acl_record, head);
                return print_signal_acl(head, acl, cond);
        }
        if (acl_type == TYPE_EXECUTE_HANDLER) {
                struct execute_handler_record *acl
                        = container_of(ptr, struct execute_handler_record,
                                       head);
                const char *keyword = KEYWORD_EXECUTE_HANDLER;
                return print_execute_handler_record(head, keyword, acl);
        }
        if (acl_type == TYPE_DENIED_EXECUTE_HANDLER) {
                struct execute_handler_record *acl
                        = container_of(ptr, struct execute_handler_record,
                                       head);
                const char *keyword = KEYWORD_DENIED_EXECUTE_HANDLER;
                return print_execute_handler_record(head, keyword, acl);
        }
        /* Workaround for gcc 3.2.2's inline bug. */
        if (acl_type & ACL_DELETED)
                return true;
        BUG(); /* This must not happen. */
        return false;
}

/**
 * read_domain_policy - Read domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
static int read_domain_policy(struct ccs_io_buffer *head)
{
        struct list1_head *dpos;
        struct list1_head *apos;
        if (head->read_eof)
                return 0;
        if (head->read_step == 0)
                head->read_step = 1;
        list1_for_each_cookie(dpos, head->read_var1, &domain_list) {
                struct domain_info *domain;
                const char *quota_exceeded = "";
                const char *transition_failed = "";
                const char *ignore_global_allow_read = "";
                const char *ignore_global_allow_env = "";
                domain = list1_entry(dpos, struct domain_info, list);
                if (head->read_step != 1)
                        goto acl_loop;
                if (domain->is_deleted)
                        continue;
                /* Print domainname and flags. */
                if (domain->quota_warned)
                        quota_exceeded = "quota_exceeded\n";
                if (domain->flags & DOMAIN_FLAGS_TRANSITION_FAILED)
                        transition_failed = "transition_failed\n";
                if (domain->flags & DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_READ)
                        ignore_global_allow_read
                                = KEYWORD_IGNORE_GLOBAL_ALLOW_READ "\n";
                if (domain->flags & DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_ENV)
                        ignore_global_allow_env
                                = KEYWORD_IGNORE_GLOBAL_ALLOW_ENV "\n";
                if (!ccs_io_printf(head, "%s\n" KEYWORD_USE_PROFILE "%u\n"
                                   "%s%s%s%s\n", domain->domainname->name,
                                   domain->profile, quota_exceeded,
                                   transition_failed,
                                   ignore_global_allow_read,
                                   ignore_global_allow_env))
                        return 0;
                head->read_step = 2;
 acl_loop:
                if (head->read_step == 3)
                        goto tail_mark;
                /* Print ACL entries in the domain. */
                list1_for_each_cookie(apos, head->read_var2,
                                      &domain->acl_info_list) {
                        struct acl_info *ptr
                                = list1_entry(apos, struct acl_info, list);
                        if (!print_entry(head, ptr))
                                return 0;
                }
                head->read_step = 3;
 tail_mark:
                if (!ccs_io_printf(head, "\n"))
                        return 0;
                head->read_step = 1;
        }
        head->read_eof = true;
        return 0;
}

#endif

/**
 * write_domain_profile - Assign profile for specified domain.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 *
 * This is equivalent to doing
 *
 *     ( echo "select " $domainname; echo "use_profile " $profile ) |
 *     /usr/lib/ccs/loadpolicy -d
 */
static int write_domain_profile(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        char *cp = strchr(data, ' ');
        struct domain_info *domain;
        unsigned int profile;
        if (!cp)
                return -EINVAL;
        *cp = '\0';
        domain = ccs_find_domain(cp + 1);
        profile = simple_strtoul(data, NULL, 10);
        if (domain && profile < MAX_PROFILES
            && (profile_ptr[profile] || !sbin_init_started))
                domain->profile = (u8) profile;
        ccs_update_counter(CCS_UPDATES_COUNTER_DOMAIN_POLICY);
        return 0;
}

/**
 * read_domain_profile - Read only domainname and profile.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns list of profile number and domainname pairs.
 *
 * This is equivalent to doing
 *
 *     grep -A 1 '^<kernel>' /proc/ccs/domain_policy |
 *     awk ' { if ( domainname == "" ) { if ( $1 == "<kernel>" )
 *     domainname = $0; } else if ( $1 == "use_profile" ) {
 *     print $2 " " domainname; domainname = ""; } } ; '
 */
static int read_domain_profile(struct ccs_io_buffer *head)
{
        struct list1_head *pos;
        if (head->read_eof)
                return 0;
        list1_for_each_cookie(pos, head->read_var1, &domain_list) {
                struct domain_info *domain;
                domain = list1_entry(pos, struct domain_info, list);
                if (domain->is_deleted)
                        continue;
                if (!ccs_io_printf(head, "%u %s\n", domain->profile,
                                   domain->domainname->name))
                        return 0;
        }
        head->read_eof = true;
        return 0;
}

/**
 * write_pid: Specify PID to obtain domainname.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
static int write_pid(struct ccs_io_buffer *head)
{
        head->read_step = (int) simple_strtoul(head->write_buf, NULL, 10);
        head->read_eof = false;
        return 0;
}

/**
 * read_pid - Get domainname of the specified PID.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns the domainname which the specified PID is in on success,
 * empty string otherwise.
 * The PID is specified by write_pid() so that the user can obtain
 * using read()/write() interface rather than sysctl() interface.
 */
static int read_pid(struct ccs_io_buffer *head)
{
        if (head->read_avail == 0 && !head->read_eof) {
                const int pid = head->read_step;
                struct task_struct *p;
                struct domain_info *domain = NULL;
                /***** CRITICAL SECTION START *****/
                read_lock(&tasklist_lock);
                p = find_task_by_pid(pid);
                if (p)
                        domain = p->domain_info;
                read_unlock(&tasklist_lock);
                /***** CRITICAL SECTION END *****/
                if (domain)
                        ccs_io_printf(head, "%d %u %s", pid, domain->profile,
                                      domain->domainname->name);
                head->read_eof = true;
        }
        return 0;
}

#ifdef CONFIG_TOMOYO

/**
 * write_exception_policy - Write exception policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int write_exception_policy(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        bool is_delete = str_starts(&data, KEYWORD_DELETE);
        if (str_starts(&data, KEYWORD_KEEP_DOMAIN))
                return ccs_write_domain_keeper_policy(data, false, is_delete);
        if (str_starts(&data, KEYWORD_NO_KEEP_DOMAIN))
                return ccs_write_domain_keeper_policy(data, true, is_delete);
        if (str_starts(&data, KEYWORD_INITIALIZE_DOMAIN))
                return ccs_write_domain_initializer_policy(data, false,
                                                           is_delete);
        if (str_starts(&data, KEYWORD_NO_INITIALIZE_DOMAIN))
                return ccs_write_domain_initializer_policy(data, true,
                                                           is_delete);
        if (str_starts(&data, KEYWORD_ALIAS))
                return ccs_write_alias_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_AGGREGATOR))
                return ccs_write_aggregator_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_ALLOW_READ))
                return ccs_write_globally_readable_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_ALLOW_ENV))
                return ccs_write_globally_usable_env_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_FILE_PATTERN))
                return ccs_write_pattern_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_PATH_GROUP))
                return ccs_write_path_group_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_DENY_REWRITE))
                return ccs_write_no_rewrite_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_ADDRESS_GROUP))
                return ccs_write_address_group_policy(data, is_delete);
        return -EINVAL;
}

/**
 * read_exception_policy - Read exception policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 */
static int read_exception_policy(struct ccs_io_buffer *head)
{
        if (!head->read_eof) {
                switch (head->read_step) {
                case 0:
                        head->read_var2 = NULL;
                        head->read_step = 1;
                case 1:
                        if (!ccs_read_domain_keeper_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 2;
                case 2:
                        if (!ccs_read_globally_readable_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 3;
                case 3:
                        if (!ccs_read_globally_usable_env_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 4;
                case 4:
                        if (!ccs_read_domain_initializer_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 5;
                case 5:
                        if (!ccs_read_alias_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 6;
                case 6:
                        if (!ccs_read_aggregator_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 7;
                case 7:
                        if (!ccs_read_file_pattern(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 8;
                case 8:
                        if (!ccs_read_no_rewrite_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 9;
                case 9:
                        if (!ccs_read_path_group_policy(head))
                                break;
                        head->read_var1 = NULL;
                        head->read_var2 = NULL;
                        head->read_step = 10;
                case 10:
                        if (!ccs_read_address_group_policy(head))
                                break;
                        head->read_eof = true;
                        break;
                default:
                        return -EINVAL;
                }
        }
        return 0;
}

#endif

#ifdef CONFIG_SAKURA

/**
 * write_system_policy - Write system policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int write_system_policy(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        bool is_delete = false;
        if (str_starts(&data, KEYWORD_DELETE))
                is_delete = true;
        if (str_starts(&data, KEYWORD_ALLOW_MOUNT))
                return ccs_write_mount_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_DENY_UNMOUNT))
                return ccs_write_no_umount_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_ALLOW_CHROOT))
                return ccs_write_chroot_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_ALLOW_PIVOT_ROOT))
                return ccs_write_pivot_root_policy(data, is_delete);
        if (str_starts(&data, KEYWORD_DENY_AUTOBIND))
                return ccs_write_reserved_port_policy(data, is_delete);
        return -EINVAL;
}

/**
 * read_system_policy - Read system policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 */
static int read_system_policy(struct ccs_io_buffer *head)
{
        if (!head->read_eof) {
                switch (head->read_step) {
                case 0:
                        head->read_var2 = NULL;
                        head->read_step = 1;
                case 1:
                        if (!ccs_read_mount_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 2;
                case 2:
                        if (!ccs_read_no_umount_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 3;
                case 3:
                        if (!ccs_read_chroot_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 4;
                case 4:
                        if (!ccs_read_pivot_root_policy(head))
                                break;
                        head->read_var2 = NULL;
                        head->read_step = 5;
                case 5:
                        if (!ccs_read_reserved_port_policy(head))
                                break;
                        head->read_eof = true;
                        break;
                default:
                        return -EINVAL;
                }
        }
        return 0;
}

#endif

/* Path to the policy loader. The default is /sbin/ccs-init. */
static const char *ccs_loader;

/**
 * loader_setup - Specify the policy loader to use.
 *
 * @str: Path to the policy loader.
 *
 * Returns 0.
 */
static int __init loader_setup(char *str)
{
        ccs_loader = str;
        return 0;
}

__setup("CCS_loader=", loader_setup);

/**
 * policy_loader_exists - Check whether /sbin/ccs-init exists.
 *
 * Returns true if /sbin/ccs-init exists, false otherwise.
 */
static bool policy_loader_exists(void)
{
        /*
         * Don't activate MAC if the path given by 'CCS_loader=' option doesn't
         * exist. If the initrd includes /sbin/init but real-root-dev has not
         * mounted on / yet, activating MAC will block the system since
         * policies are not loaded yet.
         * Thus, let do_execve() call this function everytime.
         */
        struct nameidata nd;
        if (!ccs_loader)
                ccs_loader = "/sbin/ccs-init";
        if (path_lookup(ccs_loader, lookup_flags, &nd)) {
                printk(KERN_INFO "Not activating Mandatory Access Control now "
                       "since %s doesn't exist.\n", ccs_loader);
                return false;
        }
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 25)
        path_put(&nd.path);
#else
        path_release(&nd);
#endif
        return true;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
/**
 * run_ccs_loader - Start /sbin/ccs-init .
 *
 * @unused: Not used.
 *
 * Returns PID of /sbin/ccs-init on success, negative value otherwise.
 */
static int run_ccs_loader(void *unused)
{
        char *argv[2];
        char *envp[3];
        printk(KERN_INFO "Calling %s to load policy. Please wait.\n",
               ccs_loader);
        argv[0] = (char *) ccs_loader;
        argv[1] = NULL;
        envp[0] = "HOME=/";
        envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
        envp[2] = NULL;
        return exec_usermodehelper(argv[0], argv, envp);
}
#endif

/**
 * ccs_load_policy - Run external policy loader to load policy.
 *
 * @filename: The program about to start.
 *
 * This function checks whether @filename is /sbin/init , and if so
 * invoke /sbin/ccs-init and wait for the termination of /sbin/ccs-init
 * and then continues invocation of /sbin/init.
 * /sbin/ccs-init reads policy files in /etc/ccs/ directory and
 * writes to /proc/ccs/ interfaces.
 *
 * Returns nothing.
 */
void ccs_load_policy(const char *filename)
{
        if (sbin_init_started)
                return;
        /*
         * Check filename is /sbin/init or /sbin/ccs-start.
         * /sbin/ccs-start is a dummy filename in case where /sbin/init can't
         * be passed.
         * You can create /sbin/ccs-start by "ln -s /bin/true /sbin/ccs-start".
         */
        if (strcmp(filename, "/sbin/init") &&
            strcmp(filename, "/sbin/ccs-start"))
                return;
        if (!policy_loader_exists())
                return;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 0)
        {
                char *argv[2];
                char *envp[3];
                printk(KERN_INFO "Calling %s to load policy. Please wait.\n",
                       ccs_loader);
                argv[0] = (char *) ccs_loader;
                argv[1] = NULL;
                envp[0] = "HOME=/";
                envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
                envp[2] = NULL;
                call_usermodehelper(argv[0], argv, envp, 1);
        }
#elif defined(TASK_DEAD)
        {
                /* Copied from kernel/kmod.c */
                struct task_struct *task = current;
                pid_t pid = kernel_thread(run_ccs_loader, NULL, 0);
                sigset_t tmpsig;
                spin_lock_irq(&task->sighand->siglock);
                tmpsig = task->blocked;
                siginitsetinv(&task->blocked,
                              sigmask(SIGKILL) | sigmask(SIGSTOP));
                recalc_sigpending();
                spin_unlock_irq(&current->sighand->siglock);
                if (pid >= 0)
                        waitpid(pid, NULL, __WCLONE);
                spin_lock_irq(&task->sighand->siglock);
                task->blocked = tmpsig;
                recalc_sigpending();
                spin_unlock_irq(&task->sighand->siglock);
        }
#else
        {
                /* Copied from kernel/kmod.c */
                struct task_struct *task = current;
                pid_t pid = kernel_thread(run_ccs_loader, NULL, 0);
                sigset_t tmpsig;
                spin_lock_irq(&task->sigmask_lock);
                tmpsig = task->blocked;
                siginitsetinv(&task->blocked,
                              sigmask(SIGKILL) | sigmask(SIGSTOP));
                recalc_sigpending(task);
                spin_unlock_irq(&task->sigmask_lock);
                if (pid >= 0)
                        waitpid(pid, NULL, __WCLONE);
                spin_lock_irq(&task->sigmask_lock);
                task->blocked = tmpsig;
                recalc_sigpending(task);
                spin_unlock_irq(&task->sigmask_lock);
        }
#endif
#ifdef CONFIG_SAKURA
        printk(KERN_INFO "SAKURA: 1.6.5-pre   2008/09/09\n");
#endif
#ifdef CONFIG_TOMOYO
        printk(KERN_INFO "TOMOYO: 1.6.5-pre   2008/09/09\n");
#endif
        printk(KERN_INFO "Mandatory Access Control activated.\n");
        sbin_init_started = true;
        ccs_log_level = KERN_WARNING;
        { /* Check all profiles currently assigned to domains are defined. */
                struct domain_info *domain;
                list1_for_each_entry(domain, &domain_list, list) {
                        const u8 profile = domain->profile;
                        if (profile_ptr[profile])
                                continue;
                        panic("Profile %u (used by '%s') not defined.\n",
                              profile, domain->domainname->name);
                }
        }
}

/* Wait queue for query_list. */
static DECLARE_WAIT_QUEUE_HEAD(query_wait);

/* Lock for manipurating query_list. */
static DEFINE_SPINLOCK(query_lock);

/* Structure for query. */
struct query_entry {
        struct list_head list;
        char *query;
        int query_len;
        unsigned int serial;
        int timer;
        int answer;
};

/* The list for "struct query_entry". */
static LIST_HEAD(query_list);

/* Number of "struct file" referring /proc/ccs/query interface. */
static atomic_t queryd_watcher = ATOMIC_INIT(0);

/**
 * ccs_check_supervisor - Ask for the supervisor's decision.
 *
 * @bprm: Pointer to "struct linux_binprm". May be NULL.
 * @fmt:  The printf()'s format string, followed by parameters.
 *
 * Returns 0 if the supervisor decided to permit the access request which
 * violated the policy in enforcing mode, 1 if the supervisor decided to
 * retry the access request which violated the policy in enforcing mode,
 * -EPERM otherwise.
 */
int ccs_check_supervisor(struct linux_binprm *bprm, const char *fmt, ...)
{
        va_list args;
        int error = -EPERM;
        int pos;
        int len;
        static unsigned int serial;
        struct query_entry *query_entry = NULL;
        char *header;
        if (!atomic_read(&queryd_watcher)) {
                int i;
                if (current->tomoyo_flags & CCS_DONT_SLEEP_ON_ENFORCE_ERROR)
                        return -EPERM;
                for (i = 0; i < ccs_check_flags(CCS_SLEEP_PERIOD); i++) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(HZ / 10);
                }
                return -EPERM;
        }
        va_start(args, fmt);
        len = vsnprintf((char *) &pos, sizeof(pos) - 1, fmt, args) + 32;
        va_end(args);
#ifdef CONFIG_TOMOYO
        header = ccs_init_audit_log(&len, current->domain_info->profile,
                                    3, bprm);
#else
        header = ccs_alloc(1);
#endif
        if (!header)
                goto out;
        query_entry = ccs_alloc(sizeof(*query_entry));
        if (!query_entry)
                goto out;
        query_entry->query = ccs_alloc(len);
        if (!query_entry->query)
                goto out;
        INIT_LIST_HEAD(&query_entry->list);
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        query_entry->serial = serial++;
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        pos = snprintf(query_entry->query, len - 1, "Q%u\n%s",
                       query_entry->serial, header);
        ccs_free(header);
        header = NULL;
        va_start(args, fmt);
        vsnprintf(query_entry->query + pos, len - 1 - pos, fmt, args);
        query_entry->query_len = strlen(query_entry->query) + 1;
        va_end(args);
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        list_add_tail(&query_entry->list, &query_list);
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        ccs_update_counter(CCS_UPDATES_COUNTER_QUERY);
        /* Give 10 seconds for supervisor's opinion. */
        for (query_entry->timer = 0; atomic_read(&queryd_watcher)
                     && query_entry->timer < 100; query_entry->timer++) {
                wake_up(&query_wait);
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(HZ / 10);
                if (query_entry->answer)
                        break;
        }
        ccs_update_counter(CCS_UPDATES_COUNTER_QUERY);
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        list_del(&query_entry->list);
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        switch (query_entry->answer) {
        case 3: /* Asked to retry by administrator. */
                error = 1;
                break;
        case 1:
                /* Granted by administrator. */
                error = 0;
                break;
        case 0:
                /* Timed out. */
                break;
        default:
                /* Rejected by administrator. */
                break;
        }
 out:
        if (query_entry)
                ccs_free(query_entry->query);
        ccs_free(query_entry);
        ccs_free(header);
        return error;
}

/**
 * poll_query - poll() for /proc/ccs/query.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Returns POLLIN | POLLRDNORM when ready to read, 0 otherwise.
 *
 * Waits for access requests which violated policy in enforcing mode.
 */
static int poll_query(struct file *file, poll_table *wait)
{
        bool found;
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        found = !list_empty(&query_list);
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        if (found)
                return POLLIN | POLLRDNORM;
        poll_wait(file, &query_wait, wait);
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        found = !list_empty(&query_list);
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        if (found)
                return POLLIN | POLLRDNORM;
        return 0;
}

/**
 * read_query - Read access requests which violated policy in enforcing mode.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
static int read_query(struct ccs_io_buffer *head)
{
        struct list_head *tmp;
        int pos = 0;
        int len = 0;
        char *buf;
        if (head->read_avail)
                return 0;
        if (head->read_buf) {
                ccs_free(head->read_buf);
                head->read_buf = NULL;
                head->readbuf_size = 0;
        }
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        list_for_each(tmp, &query_list) {
                struct query_entry *ptr
                        = list_entry(tmp, struct query_entry, list);
                if (pos++ != head->read_step)
                        continue;
                len = ptr->query_len;
                break;
        }
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        if (!len) {
                head->read_step = 0;
                return 0;
        }
        buf = ccs_alloc(len);
        if (buf) {
                pos = 0;
                /***** CRITICAL SECTION START *****/
                spin_lock(&query_lock);
                list_for_each(tmp, &query_list) {
                        struct query_entry *ptr
                                = list_entry(tmp, struct query_entry, list);
                        if (pos++ != head->read_step)
                                continue;
                        /*
                         * Some query can be skipped because query_list
                         * can change, but I don't care.
                         */
                        if (len == ptr->query_len)
                                memmove(buf, ptr->query, len);
                        break;
                }
                spin_unlock(&query_lock);
                /***** CRITICAL SECTION END *****/
                if (buf[0]) {
                        head->read_avail = len;
                        head->readbuf_size = head->read_avail;
                        head->read_buf = buf;
                        head->read_step++;
                } else {
                        ccs_free(buf);
                }
        }
        return 0;
}

/**
 * write_answer - Write the supervisor's decision.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 */
static int write_answer(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        struct list_head *tmp;
        unsigned int serial;
        unsigned int answer;
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        list_for_each(tmp, &query_list) {
                struct query_entry *ptr
                        = list_entry(tmp, struct query_entry, list);
                ptr->timer = 0;
        }
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        if (sscanf(data, "A%u=%u", &serial, &answer) != 2)
                return -EINVAL;
        /***** CRITICAL SECTION START *****/
        spin_lock(&query_lock);
        list_for_each(tmp, &query_list) {
                struct query_entry *ptr
                        = list_entry(tmp, struct query_entry, list);
                if (ptr->serial != serial)
                        continue;
                if (!ptr->answer)
                        ptr->answer = answer;
                break;
        }
        spin_unlock(&query_lock);
        /***** CRITICAL SECTION END *****/
        return 0;
}

/* Policy updates counter. */
static unsigned int updates_counter[MAX_CCS_UPDATES_COUNTER];

/* Policy updates counter lock. */
static DEFINE_SPINLOCK(updates_counter_lock);

/**
 * ccs_update_counter - Increment policy change counter.
 *
 * @index: Type of policy.
 *
 * Returns nothing.
 */
void ccs_update_counter(const unsigned char index)
{
        /***** CRITICAL SECTION START *****/
        spin_lock(&updates_counter_lock);
        if (index < MAX_CCS_UPDATES_COUNTER)
                updates_counter[index]++;
        spin_unlock(&updates_counter_lock);
        /***** CRITICAL SECTION END *****/
}

/**
 * read_updates_counter - Check for policy change counter.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns how many times policy has changed since the previous check.
 */
static int read_updates_counter(struct ccs_io_buffer *head)
{
        if (!head->read_eof) {
                unsigned int counter[MAX_CCS_UPDATES_COUNTER];
                /***** CRITICAL SECTION START *****/
                spin_lock(&updates_counter_lock);
                memmove(counter, updates_counter, sizeof(updates_counter));
                memset(updates_counter, 0, sizeof(updates_counter));
                spin_unlock(&updates_counter_lock);
                /***** CRITICAL SECTION END *****/
                ccs_io_printf(head,
                              "/proc/ccs/system_policy:    %10u\n"
                              "/proc/ccs/domain_policy:    %10u\n"
                              "/proc/ccs/exception_policy: %10u\n"
                              "/proc/ccs/profile:          %10u\n"
                              "/proc/ccs/query:            %10u\n"
                              "/proc/ccs/manager:          %10u\n"
                              "/proc/ccs/grant_log:        %10u\n"
                              "/proc/ccs/reject_log:       %10u\n",
                              counter[CCS_UPDATES_COUNTER_SYSTEM_POLICY],
                              counter[CCS_UPDATES_COUNTER_DOMAIN_POLICY],
                              counter[CCS_UPDATES_COUNTER_EXCEPTION_POLICY],
                              counter[CCS_UPDATES_COUNTER_PROFILE],
                              counter[CCS_UPDATES_COUNTER_QUERY],
                              counter[CCS_UPDATES_COUNTER_MANAGER],
                              counter[CCS_UPDATES_COUNTER_GRANT_LOG],
                              counter[CCS_UPDATES_COUNTER_REJECT_LOG]);
                head->read_eof = true;
        }
        return 0;
}

/**
 * read_version: Get version.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns version information.
 */
static int read_version(struct ccs_io_buffer *head)
{
        if (!head->read_eof) {
                ccs_io_printf(head, "1.6.4");
                head->read_eof = true;
        }
        return 0;
}

/**
 * read_self_domain - Get the current process's domainname.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns the current process's domainname.
 */
static int read_self_domain(struct ccs_io_buffer *head)
{
        if (!head->read_eof) {
                /*
                 * current->domain_info->domainname != NULL
                 * because every process belongs to a domain and
                 * the domain's name cannot be NULL.
                 */
                ccs_io_printf(head, "%s",
                              current->domain_info->domainname->name);
                head->read_eof = true;
        }
        return 0;
}

/**
 * ccs_open_control - open() for /proc/ccs/ interface.
 *
 * @type: Type of interface.
 * @file: Pointer to "struct file".
 *
 * Associates policy handler and returns 0 on success, -ENOMEM otherwise.
 */
int ccs_open_control(const u8 type, struct file *file)
{
        struct ccs_io_buffer *head = ccs_alloc(sizeof(*head));
        if (!head)
                return -ENOMEM;
        mutex_init(&head->read_sem);
        mutex_init(&head->write_sem);
        switch (type) {
#ifdef CONFIG_SAKURA
        case CCS_SYSTEMPOLICY: /* /proc/ccs/system_policy */
                head->write = write_system_policy;
                head->read = read_system_policy;
                break;
#endif
#ifdef CONFIG_TOMOYO
        case CCS_DOMAINPOLICY: /* /proc/ccs/domain_policy */
                head->write = write_domain_policy;
                head->read = read_domain_policy;
                break;
        case CCS_EXCEPTIONPOLICY: /* /proc/ccs/exception_policy */
                head->write = write_exception_policy;
                head->read = read_exception_policy;
                break;
        case CCS_GRANTLOG: /* /proc/ccs/grant_log */
                head->poll = ccs_poll_grant_log;
                head->read = ccs_read_grant_log;
                break;
        case CCS_REJECTLOG: /* /proc/ccs/reject_log */
                head->poll = ccs_poll_reject_log;
                head->read = ccs_read_reject_log;
                break;
#endif
        case CCS_SELFDOMAIN: /* /proc/ccs/self_domain */
                head->read = read_self_domain;
                break;
        case CCS_DOMAIN_STATUS: /* /proc/ccs/.domain_status */
                head->write = write_domain_profile;
                head->read = read_domain_profile;
                break;
        case CCS_PROCESS_STATUS: /* /proc/ccs/.process_status */
                head->write = write_pid;
                head->read = read_pid;
                break;
        case CCS_VERSION: /* /proc/ccs/version */
                head->read = read_version;
                head->readbuf_size = 128;
                break;
        case CCS_MEMINFO: /* /proc/ccs/meminfo */
                head->write = ccs_write_memory_quota;
                head->read = ccs_read_memory_counter;
                head->readbuf_size = 512;
                break;
        case CCS_PROFILE: /* /proc/ccs/profile */
                head->write = write_profile;
                head->read = read_profile;
                break;
        case CCS_QUERY: /* /proc/ccs/query */
                head->poll = poll_query;
                head->write = write_answer;
                head->read = read_query;
                break;
        case CCS_MANAGER: /* /proc/ccs/manager */
                head->write = write_manager_policy;
                head->read = read_manager_policy;
                break;
        case CCS_UPDATESCOUNTER: /* /proc/ccs/.updates_counter */
                head->read = read_updates_counter;
                break;
        }
        if (!(file->f_mode & FMODE_READ)) {
                /*
                 * No need to allocate read_buf since it is not opened
                 * for reading.
                 */
                head->read = NULL;
                head->poll = NULL;
        } else if (type != CCS_GRANTLOG && type != CCS_REJECTLOG
                   && type != CCS_QUERY) {
                /*
                 * Don't allocate buffer for reading if the file is one of
                 * /proc/ccs/grant_log , /proc/ccs/reject_log , /proc/ccs/query.
                 */
                if (!head->readbuf_size)
                        head->readbuf_size = 4096 * 2;
                head->read_buf = ccs_alloc(head->readbuf_size);
                if (!head->read_buf) {
                        ccs_free(head);
                        return -ENOMEM;
                }
        }
        if (!(file->f_mode & FMODE_WRITE)) {
                /*
                 * No need to allocate write_buf since it is not opened
                 * for writing.
                 */
                head->write = NULL;
        } else if (head->write) {
                head->writebuf_size = 4096 * 2;
                head->write_buf = ccs_alloc(head->writebuf_size);
                if (!head->write_buf) {
                        ccs_free(head->read_buf);
                        ccs_free(head);
                        return -ENOMEM;
                }
        }
        file->private_data = head;
        /*
         * Call the handler now if the file is /proc/ccs/self_domain
         * so that the user can use "cat < /proc/ccs/self_domain" to
         * know the current process's domainname.
         */
        if (type == CCS_SELFDOMAIN)
                ccs_read_control(file, NULL, 0);
        /*
         * If the file is /proc/ccs/query , increment the monitor count.
         * The monitor count is used by ccs_check_supervisor() to see if
         * there is some process monitoring /proc/ccs/query.
         */
        else if (head->write == write_answer || head->read == read_query)
                atomic_inc(&queryd_watcher);
        return 0;
}

/**
 * ccs_poll_control - poll() for /proc/ccs/ interface.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Waits for read readiness.
 * /proc/ccs/query is handled by /usr/lib/ccs/ccs-queryd and
 * /proc/ccs/grant_log and /proc/ccs/reject_log are handled by
 * /usr/lib/ccs/ccs-auditd.
 */
int ccs_poll_control(struct file *file, poll_table *wait)
{
        struct ccs_io_buffer *head = file->private_data;
        if (!head->poll)
                return -ENOSYS;
        return head->poll(file, wait);
}

/**
 * ccs_read_control - read() for /proc/ccs/ interface.
 *
 * @file:       Pointer to "struct file".
 * @buffer:     Poiner to buffer to write to.
 * @buffer_len: Size of @buffer.
 *
 * Returns bytes read on success, negative value otherwise.
 */
int ccs_read_control(struct file *file, char __user *buffer,
                     const int buffer_len)
{
        int len = 0;
        struct ccs_io_buffer *head = file->private_data;
        char *cp;
        if (!head->read)
                return -ENOSYS;
        if (!access_ok(VERIFY_WRITE, buffer, buffer_len))
                return -EFAULT;
        if (mutex_lock_interruptible(&head->read_sem))
                return -EINTR;
        /* Call the policy handler. */
        len = head->read(head);
        if (len < 0)
                goto out;
        /* Write to buffer. */
        len = head->read_avail;
        if (len > buffer_len)
                len = buffer_len;
        if (!len)
                goto out;
        /* head->read_buf changes by some functions. */
        cp = head->read_buf;
        if (copy_to_user(buffer, cp, len)) {
                len = -EFAULT;
                goto out;
        }
        head->read_avail -= len;
        memmove(cp, cp + len, head->read_avail);
 out:
        mutex_unlock(&head->read_sem);
        return len;
}

/**
 * ccs_write_control - write() for /proc/ccs/ interface.
 *
 * @file:       Pointer to "struct file".
 * @buffer:     Pointer to buffer to read from.
 * @buffer_len: Size of @buffer.
 *
 * Returns @buffer_len on success, negative value otherwise.
 */
int ccs_write_control(struct file *file, const char __user *buffer,
                      const int buffer_len)
{
        struct ccs_io_buffer *head = file->private_data;
        int error = buffer_len;
        int avail_len = buffer_len;
        char *cp0 = head->write_buf;
        if (!head->write)
                return -ENOSYS;
        if (!access_ok(VERIFY_READ, buffer, buffer_len))
                return -EFAULT;
        /* Don't allow updating policies by non manager programs. */
        if (head->write != write_pid && !is_policy_manager())
                return -EPERM;
        if (mutex_lock_interruptible(&head->write_sem))
                return -EINTR;
        /* Read a line and dispatch it to the policy handler. */
        while (avail_len > 0) {
                char c;
                if (head->write_avail >= head->writebuf_size - 1) {
                        error = -ENOMEM;
                        break;
                } else if (get_user(c, buffer)) {
                        error = -EFAULT;
                        break;
                }
                buffer++;
                avail_len--;
                cp0[head->write_avail++] = c;
                if (c != '\n')
                        continue;
                cp0[head->write_avail - 1] = '\0';
                head->write_avail = 0;
                normalize_line(cp0);
                head->write(head);
        }
        mutex_unlock(&head->write_sem);
        return error;
}

/**
 * ccs_close_control - close() for /proc/ccs/ interface.
 *
 * @file: Pointer to "struct file".
 *
 * Releases memory and returns 0.
 */
int ccs_close_control(struct file *file)
{
        struct ccs_io_buffer *head = file->private_data;
        /*
         * If the file is /proc/ccs/query , decrement the monitor count.
         */
        if (head->write == write_answer || head->read == read_query)
                atomic_dec(&queryd_watcher);
        /* Release memory used for policy I/O. */
        ccs_free(head->read_buf);
        head->read_buf = NULL;
        ccs_free(head->write_buf);
        head->write_buf = NULL;
        ccs_free(head);
        head = NULL;
        file->private_data = NULL;
        return 0;
}

/**
 * ccs_alloc_acl_element - Allocate permanent memory for ACL entry.
 *
 * @acl_type:  Type of ACL entry.
 * @condition: Pointer to condition part of the ACL entry. May be NULL.
 *
 * Returns pointer to the ACL entry on success, NULL otherwise.
 */
void *ccs_alloc_acl_element(const u8 acl_type,
                            const struct condition_list *condition)
{
        int len;
        struct acl_info *ptr;
        switch (acl_type) {
        case TYPE_SINGLE_PATH_ACL:
                len = sizeof(struct single_path_acl_record);
                break;
        case TYPE_DOUBLE_PATH_ACL:
                len = sizeof(struct double_path_acl_record);
                break;
        case TYPE_ARGV0_ACL:
                len = sizeof(struct argv0_acl_record);
                break;
        case TYPE_ENV_ACL:
                len = sizeof(struct env_acl_record);
                break;
        case TYPE_CAPABILITY_ACL:
                len = sizeof(struct capability_acl_record);
                break;
        case TYPE_IP_NETWORK_ACL:
                len = sizeof(struct ip_network_acl_record);
                break;
        case TYPE_SIGNAL_ACL:
                len = sizeof(struct signal_acl_record);
                break;
        case TYPE_EXECUTE_HANDLER:
        case TYPE_DENIED_EXECUTE_HANDLER:
                len = sizeof(struct execute_handler_record);
                break;
        default:
                return NULL;
        }
        /*
         * If the ACL doesn't have condition part, reduce memory usage
         * by eliminating sizeof(struct condition_list *).
         */
        if (!condition)
                len -= sizeof(ptr->access_me_via_ccs_get_condition_part);
        ptr = ccs_alloc_element(len);
        if (!ptr)
                return NULL;
        if (condition) {
                ptr->access_me_via_ccs_get_condition_part = condition;
                ptr->type = acl_type | ACL_WITH_CONDITION;
                return ptr;
        }
        /*
         * Substract sizeof(struct condition_list *) because I eliminated
         * sizeof(struct condition_list *) from "struct acl_info"
         * but I must return the start address of "struct acl_info".
         */
        ptr = (void *) (((u8 *) ptr)
                        - sizeof(ptr->access_me_via_ccs_get_condition_part));
        ptr->type = acl_type;
        return ptr;
}

/**
 * ccs_get_condition_part - Get condition part of the given ACL entry.
 *
 * @acl: Pointer to "struct acl_info". Pointer to an ACL entry.
 *
 * Returns pointer to the condition part if the ACL has it, NULL otherwise.
 */
const struct condition_list *ccs_get_condition_part(const struct acl_info *acl)
{
        return (acl->type & ACL_WITH_CONDITION) ?
                acl->access_me_via_ccs_get_condition_part : NULL;
}