TOMOYO: Make several options configurable.

[deliverable/linux.git] / security / tomoyo / common.c

/*
 * security/tomoyo/common.c
 *
 * Common functions for TOMOYO.
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 */

#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/security.h>
#include "common.h"

/* String table for operation mode. */
const char * const tomoyo_mode[TOMOYO_CONFIG_MAX_MODE] = {
        [TOMOYO_CONFIG_DISABLED]   = "disabled",
        [TOMOYO_CONFIG_LEARNING]   = "learning",
        [TOMOYO_CONFIG_PERMISSIVE] = "permissive",
        [TOMOYO_CONFIG_ENFORCING]  = "enforcing"
};

/* String table for /sys/kernel/security/tomoyo/profile */
const char * const tomoyo_mac_keywords[TOMOYO_MAX_MAC_INDEX
                                       + TOMOYO_MAX_MAC_CATEGORY_INDEX] = {
        [TOMOYO_MAC_FILE_EXECUTE]    = "execute",
        [TOMOYO_MAC_FILE_OPEN]       = "open",
        [TOMOYO_MAC_FILE_CREATE]     = "create",
        [TOMOYO_MAC_FILE_UNLINK]     = "unlink",
        [TOMOYO_MAC_FILE_GETATTR]    = "getattr",
        [TOMOYO_MAC_FILE_MKDIR]      = "mkdir",
        [TOMOYO_MAC_FILE_RMDIR]      = "rmdir",
        [TOMOYO_MAC_FILE_MKFIFO]     = "mkfifo",
        [TOMOYO_MAC_FILE_MKSOCK]     = "mksock",
        [TOMOYO_MAC_FILE_TRUNCATE]   = "truncate",
        [TOMOYO_MAC_FILE_SYMLINK]    = "symlink",
        [TOMOYO_MAC_FILE_MKBLOCK]    = "mkblock",
        [TOMOYO_MAC_FILE_MKCHAR]     = "mkchar",
        [TOMOYO_MAC_FILE_LINK]       = "link",
        [TOMOYO_MAC_FILE_RENAME]     = "rename",
        [TOMOYO_MAC_FILE_CHMOD]      = "chmod",
        [TOMOYO_MAC_FILE_CHOWN]      = "chown",
        [TOMOYO_MAC_FILE_CHGRP]      = "chgrp",
        [TOMOYO_MAC_FILE_IOCTL]      = "ioctl",
        [TOMOYO_MAC_FILE_CHROOT]     = "chroot",
        [TOMOYO_MAC_FILE_MOUNT]      = "mount",
        [TOMOYO_MAC_FILE_UMOUNT]     = "unmount",
        [TOMOYO_MAC_FILE_PIVOT_ROOT] = "pivot_root",
        [TOMOYO_MAX_MAC_INDEX + TOMOYO_MAC_CATEGORY_FILE] = "file",
};

/* String table for PREFERENCE keyword. */
static const char * const tomoyo_pref_keywords[TOMOYO_MAX_PREF] = {
        [TOMOYO_PREF_MAX_AUDIT_LOG]      = "max_audit_log",
        [TOMOYO_PREF_MAX_LEARNING_ENTRY] = "max_learning_entry",
};

/* String table for path operation. */
const char * const tomoyo_path_keyword[TOMOYO_MAX_PATH_OPERATION] = {
        [TOMOYO_TYPE_EXECUTE]    = "execute",
        [TOMOYO_TYPE_READ]       = "read",
        [TOMOYO_TYPE_WRITE]      = "write",
        [TOMOYO_TYPE_APPEND]     = "append",
        [TOMOYO_TYPE_UNLINK]     = "unlink",
        [TOMOYO_TYPE_GETATTR]    = "getattr",
        [TOMOYO_TYPE_RMDIR]      = "rmdir",
        [TOMOYO_TYPE_TRUNCATE]   = "truncate",
        [TOMOYO_TYPE_SYMLINK]    = "symlink",
        [TOMOYO_TYPE_CHROOT]     = "chroot",
        [TOMOYO_TYPE_UMOUNT]     = "unmount",
};

/* String table for categories. */
static const char * const tomoyo_category_keywords
[TOMOYO_MAX_MAC_CATEGORY_INDEX] = {
        [TOMOYO_MAC_CATEGORY_FILE]       = "file",
};

/* Permit policy management by non-root user? */
static bool tomoyo_manage_by_non_root;

/* Utility functions. */

/**
 * tomoyo_yesno - Return "yes" or "no".
 *
 * @value: Bool value.
 */
const char *tomoyo_yesno(const unsigned int value)
{
        return value ? "yes" : "no";
}

/**
 * tomoyo_addprintf - strncat()-like-snprintf().
 *
 * @buffer: Buffer to write to. Must be '\0'-terminated.
 * @len:    Size of @buffer.
 * @fmt:    The printf()'s format string, followed by parameters.
 *
 * Returns nothing.
 */
static void tomoyo_addprintf(char *buffer, int len, const char *fmt, ...)
{
        va_list args;
        const int pos = strlen(buffer);
        va_start(args, fmt);
        vsnprintf(buffer + pos, len - pos - 1, fmt, args);
        va_end(args);
}

/**
 * tomoyo_flush - Flush queued string to userspace's buffer.
 *
 * @head:   Pointer to "struct tomoyo_io_buffer".
 *
 * Returns true if all data was flushed, false otherwise.
 */
static bool tomoyo_flush(struct tomoyo_io_buffer *head)
{
        while (head->r.w_pos) {
                const char *w = head->r.w[0];
                size_t len = strlen(w);
                if (len) {
                        if (len > head->read_user_buf_avail)
                                len = head->read_user_buf_avail;
                        if (!len)
                                return false;
                        if (copy_to_user(head->read_user_buf, w, len))
                                return false;
                        head->read_user_buf_avail -= len;
                        head->read_user_buf += len;
                        w += len;
                }
                head->r.w[0] = w;
                if (*w)
                        return false;
                /* Add '\0' for audit logs and query. */
                if (head->poll) {
                        if (!head->read_user_buf_avail ||
                            copy_to_user(head->read_user_buf, "", 1))
                                return false;
                        head->read_user_buf_avail--;
                        head->read_user_buf++;
                }
                head->r.w_pos--;
                for (len = 0; len < head->r.w_pos; len++)
                        head->r.w[len] = head->r.w[len + 1];
        }
        head->r.avail = 0;
        return true;
}

/**
 * tomoyo_set_string - Queue string to "struct tomoyo_io_buffer" structure.
 *
 * @head:   Pointer to "struct tomoyo_io_buffer".
 * @string: String to print.
 *
 * Note that @string has to be kept valid until @head is kfree()d.
 * This means that char[] allocated on stack memory cannot be passed to
 * this function. Use tomoyo_io_printf() for char[] allocated on stack memory.
 */
static void tomoyo_set_string(struct tomoyo_io_buffer *head, const char *string)
{
        if (head->r.w_pos < TOMOYO_MAX_IO_READ_QUEUE) {
                head->r.w[head->r.w_pos++] = string;
                tomoyo_flush(head);
        } else
                WARN_ON(1);
}

/**
 * tomoyo_io_printf - printf() to "struct tomoyo_io_buffer" structure.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @fmt:  The printf()'s format string, followed by parameters.
 */
void tomoyo_io_printf(struct tomoyo_io_buffer *head, const char *fmt, ...)
{
        va_list args;
        size_t len;
        size_t pos = head->r.avail;
        int size = head->readbuf_size - pos;
        if (size <= 0)
                return;
        va_start(args, fmt);
        len = vsnprintf(head->read_buf + pos, size, fmt, args) + 1;
        va_end(args);
        if (pos + len >= head->readbuf_size) {
                WARN_ON(1);
                return;
        }
        head->r.avail += len;
        tomoyo_set_string(head, head->read_buf + pos);
}

/**
 * tomoyo_set_space - Put a space to "struct tomoyo_io_buffer" structure.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static void tomoyo_set_space(struct tomoyo_io_buffer *head)
{
        tomoyo_set_string(head, " ");
}

/**
 * tomoyo_set_lf - Put a line feed to "struct tomoyo_io_buffer" structure.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static bool tomoyo_set_lf(struct tomoyo_io_buffer *head)
{
        tomoyo_set_string(head, "\n");
        return !head->r.w_pos;
}

/**
 * tomoyo_set_slash - Put a shash to "struct tomoyo_io_buffer" structure.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static void tomoyo_set_slash(struct tomoyo_io_buffer *head)
{
        tomoyo_set_string(head, "/");
}

/* List of namespaces. */
LIST_HEAD(tomoyo_namespace_list);
/* True if namespace other than tomoyo_kernel_namespace is defined. */
static bool tomoyo_namespace_enabled;

/**
 * tomoyo_init_policy_namespace - Initialize namespace.
 *
 * @ns: Pointer to "struct tomoyo_policy_namespace".
 *
 * Returns nothing.
 */
void tomoyo_init_policy_namespace(struct tomoyo_policy_namespace *ns)
{
        unsigned int idx;
        for (idx = 0; idx < TOMOYO_MAX_ACL_GROUPS; idx++)
                INIT_LIST_HEAD(&ns->acl_group[idx]);
        for (idx = 0; idx < TOMOYO_MAX_GROUP; idx++)
                INIT_LIST_HEAD(&ns->group_list[idx]);
        for (idx = 0; idx < TOMOYO_MAX_POLICY; idx++)
                INIT_LIST_HEAD(&ns->policy_list[idx]);
        ns->profile_version = 20100903;
        tomoyo_namespace_enabled = !list_empty(&tomoyo_namespace_list);
        list_add_tail_rcu(&ns->namespace_list, &tomoyo_namespace_list);
}

/**
 * tomoyo_print_namespace - Print namespace header.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static void tomoyo_print_namespace(struct tomoyo_io_buffer *head)
{
        if (!tomoyo_namespace_enabled)
                return;
        tomoyo_set_string(head,
                          container_of(head->r.ns,
                                       struct tomoyo_policy_namespace,
                                       namespace_list)->name);
        tomoyo_set_space(head);
}

/**
 * tomoyo_print_name_union - Print a tomoyo_name_union.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @ptr:  Pointer to "struct tomoyo_name_union".
 */
static void tomoyo_print_name_union(struct tomoyo_io_buffer *head,
                                    const struct tomoyo_name_union *ptr)
{
        tomoyo_set_space(head);
        if (ptr->group) {
                tomoyo_set_string(head, "@");
                tomoyo_set_string(head, ptr->group->group_name->name);
        } else {
                tomoyo_set_string(head, ptr->filename->name);
        }
}

/**
 * tomoyo_print_number_union - Print a tomoyo_number_union.
 *
 * @head:       Pointer to "struct tomoyo_io_buffer".
 * @ptr:        Pointer to "struct tomoyo_number_union".
 */
static void tomoyo_print_number_union(struct tomoyo_io_buffer *head,
                                      const struct tomoyo_number_union *ptr)
{
        tomoyo_set_space(head);
        if (ptr->group) {
                tomoyo_set_string(head, "@");
                tomoyo_set_string(head, ptr->group->group_name->name);
        } else {
                int i;
                unsigned long min = ptr->values[0];
                const unsigned long max = ptr->values[1];
                u8 min_type = ptr->value_type[0];
                const u8 max_type = ptr->value_type[1];
                char buffer[128];
                buffer[0] = '\0';
                for (i = 0; i < 2; i++) {
                        switch (min_type) {
                        case TOMOYO_VALUE_TYPE_HEXADECIMAL:
                                tomoyo_addprintf(buffer, sizeof(buffer),
                                                 "0x%lX", min);
                                break;
                        case TOMOYO_VALUE_TYPE_OCTAL:
                                tomoyo_addprintf(buffer, sizeof(buffer),
                                                 "0%lo", min);
                                break;
                        default:
                                tomoyo_addprintf(buffer, sizeof(buffer),
                                                 "%lu", min);
                                break;
                        }
                        if (min == max && min_type == max_type)
                                break;
                        tomoyo_addprintf(buffer, sizeof(buffer), "-");
                        min_type = max_type;
                        min = max;
                }
                tomoyo_io_printf(head, "%s", buffer);
        }
}

/**
 * tomoyo_assign_profile - Create a new profile.
 *
 * @ns:      Pointer to "struct tomoyo_policy_namespace".
 * @profile: Profile number to create.
 *
 * Returns pointer to "struct tomoyo_profile" on success, NULL otherwise.
 */
static struct tomoyo_profile *tomoyo_assign_profile
(struct tomoyo_policy_namespace *ns, const unsigned int profile)
{
        struct tomoyo_profile *ptr;
        struct tomoyo_profile *entry;
        if (profile >= TOMOYO_MAX_PROFILES)
                return NULL;
        ptr = ns->profile_ptr[profile];
        if (ptr)
                return ptr;
        entry = kzalloc(sizeof(*entry), GFP_NOFS);
        if (mutex_lock_interruptible(&tomoyo_policy_lock))
                goto out;
        ptr = ns->profile_ptr[profile];
        if (!ptr && tomoyo_memory_ok(entry)) {
                ptr = entry;
                ptr->default_config = TOMOYO_CONFIG_DISABLED |
                        TOMOYO_CONFIG_WANT_GRANT_LOG |
                        TOMOYO_CONFIG_WANT_REJECT_LOG;
                memset(ptr->config, TOMOYO_CONFIG_USE_DEFAULT,
                       sizeof(ptr->config));
                ptr->pref[TOMOYO_PREF_MAX_AUDIT_LOG] = 1024;
                ptr->pref[TOMOYO_PREF_MAX_LEARNING_ENTRY] = 2048;
                mb(); /* Avoid out-of-order execution. */
                ns->profile_ptr[profile] = ptr;
                entry = NULL;
        }
        mutex_unlock(&tomoyo_policy_lock);
 out:
        kfree(entry);
        return ptr;
}

/**
 * tomoyo_profile - Find a profile.
 *
 * @ns:      Pointer to "struct tomoyo_policy_namespace".
 * @profile: Profile number to find.
 *
 * Returns pointer to "struct tomoyo_profile".
 */
struct tomoyo_profile *tomoyo_profile(const struct tomoyo_policy_namespace *ns,
                                      const u8 profile)
{
        static struct tomoyo_profile tomoyo_null_profile;
        struct tomoyo_profile *ptr = ns->profile_ptr[profile];
        if (!ptr)
                ptr = &tomoyo_null_profile;
        return ptr;
}

/**
 * tomoyo_find_yesno - Find values for specified keyword.
 *
 * @string: String to check.
 * @find:   Name of keyword.
 *
 * Returns 1 if "@find=yes" was found, 0 if "@find=no" was found, -1 otherwise.
 */
static s8 tomoyo_find_yesno(const char *string, const char *find)
{
        const char *cp = strstr(string, find);
        if (cp) {
                cp += strlen(find);
                if (!strncmp(cp, "=yes", 4))
                        return 1;
                else if (!strncmp(cp, "=no", 3))
                        return 0;
        }
        return -1;
}

/**
 * tomoyo_set_uint - Set value for specified preference.
 *
 * @i:      Pointer to "unsigned int".
 * @string: String to check.
 * @find:   Name of keyword.
 *
 * Returns nothing.
 */
static void tomoyo_set_uint(unsigned int *i, const char *string,
                            const char *find)
{
        const char *cp = strstr(string, find);
        if (cp)
                sscanf(cp + strlen(find), "=%u", i);
}

/**
 * tomoyo_set_mode - Set mode for specified profile.
 *
 * @name:    Name of functionality.
 * @value:   Mode for @name.
 * @profile: Pointer to "struct tomoyo_profile".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_set_mode(char *name, const char *value,
                           struct tomoyo_profile *profile)
{
        u8 i;
        u8 config;
        if (!strcmp(name, "CONFIG")) {
                i = TOMOYO_MAX_MAC_INDEX + TOMOYO_MAX_MAC_CATEGORY_INDEX;
                config = profile->default_config;
        } else if (tomoyo_str_starts(&name, "CONFIG::")) {
                config = 0;
                for (i = 0; i < TOMOYO_MAX_MAC_INDEX
                             + TOMOYO_MAX_MAC_CATEGORY_INDEX; i++) {
                        int len = 0;
                        if (i < TOMOYO_MAX_MAC_INDEX) {
                                const u8 c = tomoyo_index2category[i];
                                const char *category =
                                        tomoyo_category_keywords[c];
                                len = strlen(category);
                                if (strncmp(name, category, len) ||
                                    name[len++] != ':' || name[len++] != ':')
                                        continue;
                        }
                        if (strcmp(name + len, tomoyo_mac_keywords[i]))
                                continue;
                        config = profile->config[i];
                        break;
                }
                if (i == TOMOYO_MAX_MAC_INDEX + TOMOYO_MAX_MAC_CATEGORY_INDEX)
                        return -EINVAL;
        } else {
                return -EINVAL;
        }
        if (strstr(value, "use_default")) {
                config = TOMOYO_CONFIG_USE_DEFAULT;
        } else {
                u8 mode;
                for (mode = 0; mode < 4; mode++)
                        if (strstr(value, tomoyo_mode[mode]))
                                /*
                                 * Update lower 3 bits in order to distinguish
                                 * 'config' from 'TOMOYO_CONFIG_USE_DEAFULT'.
                                 */
                                config = (config & ~7) | mode;
                if (config != TOMOYO_CONFIG_USE_DEFAULT) {
                        switch (tomoyo_find_yesno(value, "grant_log")) {
                        case 1:
                                config |= TOMOYO_CONFIG_WANT_GRANT_LOG;
                                break;
                        case 0:
                                config &= ~TOMOYO_CONFIG_WANT_GRANT_LOG;
                                break;
                        }
                        switch (tomoyo_find_yesno(value, "reject_log")) {
                        case 1:
                                config |= TOMOYO_CONFIG_WANT_REJECT_LOG;
                                break;
                        case 0:
                                config &= ~TOMOYO_CONFIG_WANT_REJECT_LOG;
                                break;
                        }
                }
        }
        if (i < TOMOYO_MAX_MAC_INDEX + TOMOYO_MAX_MAC_CATEGORY_INDEX)
                profile->config[i] = config;
        else if (config != TOMOYO_CONFIG_USE_DEFAULT)
                profile->default_config = config;
        return 0;
}

/**
 * tomoyo_write_profile - Write profile table.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_write_profile(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;
        unsigned int i;
        char *cp;
        struct tomoyo_profile *profile;
        if (sscanf(data, "PROFILE_VERSION=%u", &head->w.ns->profile_version)
            == 1)
                return 0;
        i = simple_strtoul(data, &cp, 10);
        if (*cp != '-')
                return -EINVAL;
        data = cp + 1;
        profile = tomoyo_assign_profile(head->w.ns, i);
        if (!profile)
                return -EINVAL;
        cp = strchr(data, '=');
        if (!cp)
                return -EINVAL;
        *cp++ = '\0';
        if (!strcmp(data, "COMMENT")) {
                static DEFINE_SPINLOCK(lock);
                const struct tomoyo_path_info *new_comment
                        = tomoyo_get_name(cp);
                const struct tomoyo_path_info *old_comment;
                if (!new_comment)
                        return -ENOMEM;
                spin_lock(&lock);
                old_comment = profile->comment;
                profile->comment = new_comment;
                spin_unlock(&lock);
                tomoyo_put_name(old_comment);
                return 0;
        }
        if (!strcmp(data, "PREFERENCE")) {
                for (i = 0; i < TOMOYO_MAX_PREF; i++)
                        tomoyo_set_uint(&profile->pref[i], cp,
                                        tomoyo_pref_keywords[i]);
                return 0;
        }
        return tomoyo_set_mode(data, cp, profile);
}

/**
 * tomoyo_print_config - Print mode for specified functionality.
 *
 * @head:   Pointer to "struct tomoyo_io_buffer".
 * @config: Mode for that functionality.
 *
 * Returns nothing.
 *
 * Caller prints functionality's name.
 */
static void tomoyo_print_config(struct tomoyo_io_buffer *head, const u8 config)
{
        tomoyo_io_printf(head, "={ mode=%s grant_log=%s reject_log=%s }\n",
                         tomoyo_mode[config & 3],
                         tomoyo_yesno(config & TOMOYO_CONFIG_WANT_GRANT_LOG),
                         tomoyo_yesno(config & TOMOYO_CONFIG_WANT_REJECT_LOG));
}

/**
 * tomoyo_read_profile - Read profile table.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static void tomoyo_read_profile(struct tomoyo_io_buffer *head)
{
        u8 index;
        struct tomoyo_policy_namespace *ns =
                container_of(head->r.ns, typeof(*ns), namespace_list);
        const struct tomoyo_profile *profile;
        if (head->r.eof)
                return;
 next:
        index = head->r.index;
        profile = ns->profile_ptr[index];
        switch (head->r.step) {
        case 0:
                tomoyo_print_namespace(head);
                tomoyo_io_printf(head, "PROFILE_VERSION=%u\n",
                                 ns->profile_version);
                head->r.step++;
                break;
        case 1:
                for ( ; head->r.index < TOMOYO_MAX_PROFILES;
                      head->r.index++)
                        if (ns->profile_ptr[head->r.index])
                                break;
                if (head->r.index == TOMOYO_MAX_PROFILES)
                        return;
                head->r.step++;
                break;
        case 2:
                {
                        u8 i;
                        const struct tomoyo_path_info *comment =
                                profile->comment;
                        tomoyo_print_namespace(head);
                        tomoyo_io_printf(head, "%u-COMMENT=", index);
                        tomoyo_set_string(head, comment ? comment->name : "");
                        tomoyo_set_lf(head);
                        tomoyo_io_printf(head, "%u-PREFERENCE={ ", index);
                        for (i = 0; i < TOMOYO_MAX_PREF; i++)
                                tomoyo_io_printf(head, "%s=%u ",
                                                 tomoyo_pref_keywords[i],
                                                 profile->pref[i]);
                        tomoyo_set_string(head, "}\n");
                        head->r.step++;
                }
                break;
        case 3:
                {
                        tomoyo_print_namespace(head);
                        tomoyo_io_printf(head, "%u-%s", index, "CONFIG");
                        tomoyo_print_config(head, profile->default_config);
                        head->r.bit = 0;
                        head->r.step++;
                }
                break;
        case 4:
                for ( ; head->r.bit < TOMOYO_MAX_MAC_INDEX
                              + TOMOYO_MAX_MAC_CATEGORY_INDEX; head->r.bit++) {
                        const u8 i = head->r.bit;
                        const u8 config = profile->config[i];
                        if (config == TOMOYO_CONFIG_USE_DEFAULT)
                                continue;
                        tomoyo_print_namespace(head);
                        if (i < TOMOYO_MAX_MAC_INDEX)
                                tomoyo_io_printf(head, "%u-CONFIG::%s::%s",
                                                 index,
                                                 tomoyo_category_keywords
                                                 [tomoyo_index2category[i]],
                                                 tomoyo_mac_keywords[i]);
                        else
                                tomoyo_io_printf(head, "%u-CONFIG::%s", index,
                                                 tomoyo_mac_keywords[i]);
                        tomoyo_print_config(head, config);
                        head->r.bit++;
                        break;
                }
                if (head->r.bit == TOMOYO_MAX_MAC_INDEX
                    + TOMOYO_MAX_MAC_CATEGORY_INDEX) {
                        head->r.index++;
                        head->r.step = 1;
                }
                break;
        }
        if (tomoyo_flush(head))
                goto next;
}

static bool tomoyo_same_manager(const struct tomoyo_acl_head *a,
                                const struct tomoyo_acl_head *b)
{
        return container_of(a, struct tomoyo_manager, head)->manager ==
                container_of(b, struct tomoyo_manager, head)->manager;
}

/**
 * tomoyo_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.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_manager_entry(const char *manager,
                                       const bool is_delete)
{
        struct tomoyo_manager e = { };
        struct tomoyo_acl_param param = {
                /* .ns = &tomoyo_kernel_namespace, */
                .is_delete = is_delete,
                .list = &tomoyo_kernel_namespace.
                policy_list[TOMOYO_ID_MANAGER],
        };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (tomoyo_domain_def(manager)) {
                if (!tomoyo_correct_domain(manager))
                        return -EINVAL;
                e.is_domain = true;
        } else {
                if (!tomoyo_correct_path(manager))
                        return -EINVAL;
        }
        e.manager = tomoyo_get_name(manager);
        if (e.manager) {
                error = tomoyo_update_policy(&e.head, sizeof(e), &param,
                                             tomoyo_same_manager);
                tomoyo_put_name(e.manager);
        }
        return error;
}

/**
 * tomoyo_write_manager - Write manager policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_manager(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;

        if (!strcmp(data, "manage_by_non_root")) {
                tomoyo_manage_by_non_root = !head->w.is_delete;
                return 0;
        }
        return tomoyo_update_manager_entry(data, head->w.is_delete);
}

/**
 * tomoyo_read_manager - Read manager policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Caller holds tomoyo_read_lock().
 */
static void tomoyo_read_manager(struct tomoyo_io_buffer *head)
{
        if (head->r.eof)
                return;
        list_for_each_cookie(head->r.acl, &tomoyo_kernel_namespace.
                             policy_list[TOMOYO_ID_MANAGER]) {
                struct tomoyo_manager *ptr =
                        list_entry(head->r.acl, typeof(*ptr), head.list);
                if (ptr->head.is_deleted)
                        continue;
                if (!tomoyo_flush(head))
                        return;
                tomoyo_set_string(head, ptr->manager->name);
                tomoyo_set_lf(head);
        }
        head->r.eof = true;
}

/**
 * tomoyo_manager - Check whether the current process is a policy manager.
 *
 * Returns true if the current process is permitted to modify policy
 * via /sys/kernel/security/tomoyo/ interface.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_manager(void)
{
        struct tomoyo_manager *ptr;
        const char *exe;
        const struct task_struct *task = current;
        const struct tomoyo_path_info *domainname = tomoyo_domain()->domainname;
        bool found = false;

        if (!tomoyo_policy_loaded)
                return true;
        if (!tomoyo_manage_by_non_root && (task->cred->uid || task->cred->euid))
                return false;
        list_for_each_entry_rcu(ptr, &tomoyo_kernel_namespace.
                                policy_list[TOMOYO_ID_MANAGER], head.list) {
                if (!ptr->head.is_deleted && ptr->is_domain
                    && !tomoyo_pathcmp(domainname, ptr->manager)) {
                        found = true;
                        break;
                }
        }
        if (found)
                return true;
        exe = tomoyo_get_exe();
        if (!exe)
                return false;
        list_for_each_entry_rcu(ptr, &tomoyo_kernel_namespace.
                                policy_list[TOMOYO_ID_MANAGER], head.list) {
                if (!ptr->head.is_deleted && !ptr->is_domain
                    && !strcmp(exe, ptr->manager->name)) {
                        found = true;
                        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;
                }
        }
        kfree(exe);
        return found;
}

/**
 * tomoyo_select_domain - Parse select command.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @data: String to parse.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_select_domain(struct tomoyo_io_buffer *head,
                                 const char *data)
{
        unsigned int pid;
        struct tomoyo_domain_info *domain = NULL;
        bool global_pid = false;
        if (strncmp(data, "select ", 7))
                return false;
        data += 7;
        if (sscanf(data, "pid=%u", &pid) == 1 ||
            (global_pid = true, sscanf(data, "global-pid=%u", &pid) == 1)) {
                struct task_struct *p;
                rcu_read_lock();
                read_lock(&tasklist_lock);
                if (global_pid)
                        p = find_task_by_pid_ns(pid, &init_pid_ns);
                else
                        p = find_task_by_vpid(pid);
                if (p)
                        domain = tomoyo_real_domain(p);
                read_unlock(&tasklist_lock);
                rcu_read_unlock();
        } else if (!strncmp(data, "domain=", 7)) {
                if (tomoyo_domain_def(data + 7))
                        domain = tomoyo_find_domain(data + 7);
        } else
                return false;
        head->w.domain = domain;
        /* Accessing read_buf is safe because head->io_sem is held. */
        if (!head->read_buf)
                return true; /* Do nothing if open(O_WRONLY). */
        memset(&head->r, 0, sizeof(head->r));
        head->r.print_this_domain_only = true;
        if (domain)
                head->r.domain = &domain->list;
        else
                head->r.eof = 1;
        tomoyo_io_printf(head, "# select %s\n", data);
        if (domain && domain->is_deleted)
                tomoyo_io_printf(head, "# This is a deleted domain.\n");
        return true;
}

/**
 * tomoyo_delete_domain - Delete a domain.
 *
 * @domainname: The name of domain.
 *
 * Returns 0.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_delete_domain(char *domainname)
{
        struct tomoyo_domain_info *domain;
        struct tomoyo_path_info name;

        name.name = domainname;
        tomoyo_fill_path_info(&name);
        if (mutex_lock_interruptible(&tomoyo_policy_lock))
                return 0;
        /* Is there an active domain? */
        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
                /* Never delete tomoyo_kernel_domain */
                if (domain == &tomoyo_kernel_domain)
                        continue;
                if (domain->is_deleted ||
                    tomoyo_pathcmp(domain->domainname, &name))
                        continue;
                domain->is_deleted = true;
                break;
        }
        mutex_unlock(&tomoyo_policy_lock);
        return 0;
}

/**
 * tomoyo_write_domain2 - Write domain policy.
 *
 * @ns:        Pointer to "struct tomoyo_policy_namespace".
 * @list:      Pointer to "struct list_head".
 * @data:      Policy to be interpreted.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_domain2(struct tomoyo_policy_namespace *ns,
                                struct list_head *list, char *data,
                                const bool is_delete)
{
        struct tomoyo_acl_param param = {
                .ns = ns,
                .list = list,
                .data = data,
                .is_delete = is_delete,
        };
        static const struct {
                const char *keyword;
                int (*write) (struct tomoyo_acl_param *);
        } tomoyo_callback[1] = {
                { "file ", tomoyo_write_file },
        };
        u8 i;
        for (i = 0; i < 1; i++) {
                if (!tomoyo_str_starts(&param.data,
                                       tomoyo_callback[i].keyword))
                        continue;
                return tomoyo_callback[i].write(&param);
        }
        return -EINVAL;
}

/* String table for domain flags. */
const char * const tomoyo_dif[TOMOYO_MAX_DOMAIN_INFO_FLAGS] = {
        [TOMOYO_DIF_QUOTA_WARNED]      = "quota_exceeded\n",
        [TOMOYO_DIF_TRANSITION_FAILED] = "transition_failed\n",
};

/**
 * tomoyo_write_domain - Write domain policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_domain(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;
        struct tomoyo_policy_namespace *ns;
        struct tomoyo_domain_info *domain = head->w.domain;
        const bool is_delete = head->w.is_delete;
        bool is_select = !is_delete && tomoyo_str_starts(&data, "select ");
        unsigned int profile;
        if (*data == '<') {
                domain = NULL;
                if (is_delete)
                        tomoyo_delete_domain(data);
                else if (is_select)
                        domain = tomoyo_find_domain(data);
                else
                        domain = tomoyo_assign_domain(data, false);
                head->w.domain = domain;
                return 0;
        }
        if (!domain)
                return -EINVAL;
        ns = domain->ns;
        if (sscanf(data, "use_profile %u", &profile) == 1
            && profile < TOMOYO_MAX_PROFILES) {
                if (!tomoyo_policy_loaded || ns->profile_ptr[profile])
                        domain->profile = (u8) profile;
                return 0;
        }
        if (sscanf(data, "use_group %u\n", &profile) == 1
            && profile < TOMOYO_MAX_ACL_GROUPS) {
                if (!is_delete)
                        domain->group = (u8) profile;
                return 0;
        }
        for (profile = 0; profile < TOMOYO_MAX_DOMAIN_INFO_FLAGS; profile++) {
                const char *cp = tomoyo_dif[profile];
                if (strncmp(data, cp, strlen(cp) - 1))
                        continue;
                domain->flags[profile] = !is_delete;
                return 0;
        }
        return tomoyo_write_domain2(ns, &domain->acl_info_list, data,
                                    is_delete);
}

/**
 * tomoyo_set_group - Print "acl_group " header keyword and category name.
 *
 * @head:     Pointer to "struct tomoyo_io_buffer".
 * @category: Category name.
 *
 * Returns nothing.
 */
static void tomoyo_set_group(struct tomoyo_io_buffer *head,
                             const char *category)
{
        if (head->type == TOMOYO_EXCEPTIONPOLICY) {
                tomoyo_print_namespace(head);
                tomoyo_io_printf(head, "acl_group %u ",
                                 head->r.acl_group_index);
        }
        tomoyo_set_string(head, category);
}

/**
 * tomoyo_print_entry - Print an ACL entry.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @acl:  Pointer to an ACL entry.
 *
 * Returns true on success, false otherwise.
 */
static bool tomoyo_print_entry(struct tomoyo_io_buffer *head,
                               struct tomoyo_acl_info *acl)
{
        const u8 acl_type = acl->type;
        bool first = true;
        u8 bit;

        if (acl->is_deleted)
                return true;
        if (!tomoyo_flush(head))
                return false;
        else if (acl_type == TOMOYO_TYPE_PATH_ACL) {
                struct tomoyo_path_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u16 perm = ptr->perm;
                for (bit = 0; bit < TOMOYO_MAX_PATH_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (head->r.print_transition_related_only &&
                            bit != TOMOYO_TYPE_EXECUTE)
                                continue;
                        if (first) {
                                tomoyo_set_group(head, "file ");
                                first = false;
                        } else {
                                tomoyo_set_slash(head);
                        }
                        tomoyo_set_string(head, tomoyo_path_keyword[bit]);
                }
                if (first)
                        return true;
                tomoyo_print_name_union(head, &ptr->name);
        } else if (head->r.print_transition_related_only) {
                return true;
        } else if (acl_type == TOMOYO_TYPE_PATH2_ACL) {
                struct tomoyo_path2_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < TOMOYO_MAX_PATH2_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                tomoyo_set_group(head, "file ");
                                first = false;
                        } else {
                                tomoyo_set_slash(head);
                        }
                        tomoyo_set_string(head, tomoyo_mac_keywords
                                          [tomoyo_pp2mac[bit]]);
                }
                if (first)
                        return true;
                tomoyo_print_name_union(head, &ptr->name1);
                tomoyo_print_name_union(head, &ptr->name2);
        } else if (acl_type == TOMOYO_TYPE_PATH_NUMBER_ACL) {
                struct tomoyo_path_number_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < TOMOYO_MAX_PATH_NUMBER_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                tomoyo_set_group(head, "file ");
                                first = false;
                        } else {
                                tomoyo_set_slash(head);
                        }
                        tomoyo_set_string(head, tomoyo_mac_keywords
                                          [tomoyo_pn2mac[bit]]);
                }
                if (first)
                        return true;
                tomoyo_print_name_union(head, &ptr->name);
                tomoyo_print_number_union(head, &ptr->number);
        } else if (acl_type == TOMOYO_TYPE_MKDEV_ACL) {
                struct tomoyo_mkdev_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < TOMOYO_MAX_MKDEV_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                tomoyo_set_group(head, "file ");
                                first = false;
                        } else {
                                tomoyo_set_slash(head);
                        }
                        tomoyo_set_string(head, tomoyo_mac_keywords
                                          [tomoyo_pnnn2mac[bit]]);
                }
                if (first)
                        return true;
                tomoyo_print_name_union(head, &ptr->name);
                tomoyo_print_number_union(head, &ptr->mode);
                tomoyo_print_number_union(head, &ptr->major);
                tomoyo_print_number_union(head, &ptr->minor);
        } else if (acl_type == TOMOYO_TYPE_MOUNT_ACL) {
                struct tomoyo_mount_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                tomoyo_set_group(head, "file mount");
                tomoyo_print_name_union(head, &ptr->dev_name);
                tomoyo_print_name_union(head, &ptr->dir_name);
                tomoyo_print_name_union(head, &ptr->fs_type);
                tomoyo_print_number_union(head, &ptr->flags);
        }
        tomoyo_set_lf(head);
        return true;
}

/**
 * tomoyo_read_domain2 - Read domain policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @list: Pointer to "struct list_head".
 *
 * Caller holds tomoyo_read_lock().
 *
 * Returns true on success, false otherwise.
 */
static bool tomoyo_read_domain2(struct tomoyo_io_buffer *head,
                                struct list_head *list)
{
        list_for_each_cookie(head->r.acl, list) {
                struct tomoyo_acl_info *ptr =
                        list_entry(head->r.acl, typeof(*ptr), list);
                if (!tomoyo_print_entry(head, ptr))
                        return false;
        }
        head->r.acl = NULL;
        return true;
}

/**
 * tomoyo_read_domain - Read domain policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Caller holds tomoyo_read_lock().
 */
static void tomoyo_read_domain(struct tomoyo_io_buffer *head)
{
        if (head->r.eof)
                return;
        list_for_each_cookie(head->r.domain, &tomoyo_domain_list) {
                struct tomoyo_domain_info *domain =
                        list_entry(head->r.domain, typeof(*domain), list);
                switch (head->r.step) {
                        u8 i;
                case 0:
                        if (domain->is_deleted &&
                            !head->r.print_this_domain_only)
                                continue;
                        /* Print domainname and flags. */
                        tomoyo_set_string(head, domain->domainname->name);
                        tomoyo_set_lf(head);
                        tomoyo_io_printf(head, "use_profile %u\n",
                                         domain->profile);
                        tomoyo_io_printf(head, "use_group %u\n",
                                         domain->group);
                        for (i = 0; i < TOMOYO_MAX_DOMAIN_INFO_FLAGS; i++)
                                if (domain->flags[i])
                                        tomoyo_set_string(head, tomoyo_dif[i]);
                        head->r.step++;
                        tomoyo_set_lf(head);
                        /* fall through */
                case 1:
                        if (!tomoyo_read_domain2(head, &domain->acl_info_list))
                                return;
                        head->r.step++;
                        if (!tomoyo_set_lf(head))
                                return;
                        /* fall through */
                case 2:
                        head->r.step = 0;
                        if (head->r.print_this_domain_only)
                                goto done;
                }
        }
 done:
        head->r.eof = true;
}

/**
 * tomoyo_write_domain_profile - Assign profile for specified domain.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 *
 * This is equivalent to doing
 *
 *     ( echo "select " $domainname; echo "use_profile " $profile ) |
 *     /usr/sbin/tomoyo-loadpolicy -d
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_domain_profile(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;
        char *cp = strchr(data, ' ');
        struct tomoyo_domain_info *domain;
        unsigned long profile;

        if (!cp)
                return -EINVAL;
        *cp = '\0';
        domain = tomoyo_find_domain(cp + 1);
        if (strict_strtoul(data, 10, &profile))
                return -EINVAL;
        if (domain && (!tomoyo_policy_loaded ||
                       head->w.ns->profile_ptr[(u8) profile]))
                domain->profile = (u8) profile;
        return 0;
}

/**
 * tomoyo_read_domain_profile - Read only domainname and profile.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns list of profile number and domainname pairs.
 *
 * This is equivalent to doing
 *
 *     grep -A 1 '^<kernel>' /sys/kernel/security/tomoyo/domain_policy |
 *     awk ' { if ( domainname == "" ) { if ( $1 == "<kernel>" )
 *     domainname = $0; } else if ( $1 == "use_profile" ) {
 *     print $2 " " domainname; domainname = ""; } } ; '
 *
 * Caller holds tomoyo_read_lock().
 */
static void tomoyo_read_domain_profile(struct tomoyo_io_buffer *head)
{
        if (head->r.eof)
                return;
        list_for_each_cookie(head->r.domain, &tomoyo_domain_list) {
                struct tomoyo_domain_info *domain =
                        list_entry(head->r.domain, typeof(*domain), list);
                if (domain->is_deleted)
                        continue;
                if (!tomoyo_flush(head))
                        return;
                tomoyo_io_printf(head, "%u ", domain->profile);
                tomoyo_set_string(head, domain->domainname->name);
                tomoyo_set_lf(head);
        }
        head->r.eof = true;
}

/**
 * tomoyo_write_pid: Specify PID to obtain domainname.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0.
 */
static int tomoyo_write_pid(struct tomoyo_io_buffer *head)
{
        head->r.eof = false;
        return 0;
}

/**
 * tomoyo_read_pid - Get domainname of the specified PID.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns the domainname which the specified PID is in on success,
 * empty string otherwise.
 * The PID is specified by tomoyo_write_pid() so that the user can obtain
 * using read()/write() interface rather than sysctl() interface.
 */
static void tomoyo_read_pid(struct tomoyo_io_buffer *head)
{
        char *buf = head->write_buf;
        bool global_pid = false;
        unsigned int pid;
        struct task_struct *p;
        struct tomoyo_domain_info *domain = NULL;

        /* Accessing write_buf is safe because head->io_sem is held. */
        if (!buf) {
                head->r.eof = true;
                return; /* Do nothing if open(O_RDONLY). */
        }
        if (head->r.w_pos || head->r.eof)
                return;
        head->r.eof = true;
        if (tomoyo_str_starts(&buf, "global-pid "))
                global_pid = true;
        pid = (unsigned int) simple_strtoul(buf, NULL, 10);
        rcu_read_lock();
        read_lock(&tasklist_lock);
        if (global_pid)
                p = find_task_by_pid_ns(pid, &init_pid_ns);
        else
                p = find_task_by_vpid(pid);
        if (p)
                domain = tomoyo_real_domain(p);
        read_unlock(&tasklist_lock);
        rcu_read_unlock();
        if (!domain)
                return;
        tomoyo_io_printf(head, "%u %u ", pid, domain->profile);
        tomoyo_set_string(head, domain->domainname->name);
}

static const char *tomoyo_transition_type[TOMOYO_MAX_TRANSITION_TYPE] = {
        [TOMOYO_TRANSITION_CONTROL_NO_RESET]      = "no_reset_domain ",
        [TOMOYO_TRANSITION_CONTROL_RESET]         = "reset_domain ",
        [TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE] = "no_initialize_domain ",
        [TOMOYO_TRANSITION_CONTROL_INITIALIZE]    = "initialize_domain ",
        [TOMOYO_TRANSITION_CONTROL_NO_KEEP]       = "no_keep_domain ",
        [TOMOYO_TRANSITION_CONTROL_KEEP]          = "keep_domain ",
};

static const char *tomoyo_group_name[TOMOYO_MAX_GROUP] = {
        [TOMOYO_PATH_GROUP]   = "path_group ",
        [TOMOYO_NUMBER_GROUP] = "number_group ",
};

/**
 * tomoyo_write_exception - Write exception policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_write_exception(struct tomoyo_io_buffer *head)
{
        const bool is_delete = head->w.is_delete;
        struct tomoyo_acl_param param = {
                .ns = head->w.ns,
                .is_delete = is_delete,
                .data = head->write_buf,
        };
        u8 i;
        if (tomoyo_str_starts(&param.data, "aggregator "))
                return tomoyo_write_aggregator(&param);
        for (i = 0; i < TOMOYO_MAX_TRANSITION_TYPE; i++)
                if (tomoyo_str_starts(&param.data, tomoyo_transition_type[i]))
                        return tomoyo_write_transition_control(&param, i);
        for (i = 0; i < TOMOYO_MAX_GROUP; i++)
                if (tomoyo_str_starts(&param.data, tomoyo_group_name[i]))
                        return tomoyo_write_group(&param, i);
        if (tomoyo_str_starts(&param.data, "acl_group ")) {
                unsigned int group;
                char *data;
                group = simple_strtoul(param.data, &data, 10);
                if (group < TOMOYO_MAX_ACL_GROUPS && *data++ == ' ')
                        return tomoyo_write_domain2
                                (head->w.ns, &head->w.ns->acl_group[group],
                                 data, is_delete);
        }
        return -EINVAL;
}

/**
 * tomoyo_read_group - Read "struct tomoyo_path_group"/"struct tomoyo_number_group" list.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @idx:  Index number.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_read_group(struct tomoyo_io_buffer *head, const int idx)
{
        struct tomoyo_policy_namespace *ns =
                container_of(head->r.ns, typeof(*ns), namespace_list);
        struct list_head *list = &ns->group_list[idx];
        list_for_each_cookie(head->r.group, list) {
                struct tomoyo_group *group =
                        list_entry(head->r.group, typeof(*group), head.list);
                list_for_each_cookie(head->r.acl, &group->member_list) {
                        struct tomoyo_acl_head *ptr =
                                list_entry(head->r.acl, typeof(*ptr), list);
                        if (ptr->is_deleted)
                                continue;
                        if (!tomoyo_flush(head))
                                return false;
                        tomoyo_print_namespace(head);
                        tomoyo_set_string(head, tomoyo_group_name[idx]);
                        tomoyo_set_string(head, group->group_name->name);
                        if (idx == TOMOYO_PATH_GROUP) {
                                tomoyo_set_space(head);
                                tomoyo_set_string(head, container_of
                                               (ptr, struct tomoyo_path_group,
                                                head)->member_name->name);
                        } else if (idx == TOMOYO_NUMBER_GROUP) {
                                tomoyo_print_number_union(head, &container_of
                                                          (ptr,
                                                   struct tomoyo_number_group,
                                                           head)->number);
                        }
                        tomoyo_set_lf(head);
                }
                head->r.acl = NULL;
        }
        head->r.group = NULL;
        return true;
}

/**
 * tomoyo_read_policy - Read "struct tomoyo_..._entry" list.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 * @idx:  Index number.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_read_policy(struct tomoyo_io_buffer *head, const int idx)
{
        struct tomoyo_policy_namespace *ns =
                container_of(head->r.ns, typeof(*ns), namespace_list);
        struct list_head *list = &ns->policy_list[idx];
        list_for_each_cookie(head->r.acl, list) {
                struct tomoyo_acl_head *acl =
                        container_of(head->r.acl, typeof(*acl), list);
                if (acl->is_deleted)
                        continue;
                if (!tomoyo_flush(head))
                        return false;
                switch (idx) {
                case TOMOYO_ID_TRANSITION_CONTROL:
                        {
                                struct tomoyo_transition_control *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                tomoyo_print_namespace(head);
                                tomoyo_set_string(head, tomoyo_transition_type
                                                  [ptr->type]);
                                tomoyo_set_string(head, ptr->program ?
                                                  ptr->program->name : "any");
                                tomoyo_set_string(head, " from ");
                                tomoyo_set_string(head, ptr->domainname ?
                                                  ptr->domainname->name :
                                                  "any");
                        }
                        break;
                case TOMOYO_ID_AGGREGATOR:
                        {
                                struct tomoyo_aggregator *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                tomoyo_print_namespace(head);
                                tomoyo_set_string(head, "aggregator ");
                                tomoyo_set_string(head,
                                                  ptr->original_name->name);
                                tomoyo_set_space(head);
                                tomoyo_set_string(head,
                                               ptr->aggregated_name->name);
                        }
                        break;
                default:
                        continue;
                }
                tomoyo_set_lf(head);
        }
        head->r.acl = NULL;
        return true;
}

/**
 * tomoyo_read_exception - Read exception policy.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Caller holds tomoyo_read_lock().
 */
static void tomoyo_read_exception(struct tomoyo_io_buffer *head)
{
        struct tomoyo_policy_namespace *ns =
                container_of(head->r.ns, typeof(*ns), namespace_list);
        if (head->r.eof)
                return;
        while (head->r.step < TOMOYO_MAX_POLICY &&
               tomoyo_read_policy(head, head->r.step))
                head->r.step++;
        if (head->r.step < TOMOYO_MAX_POLICY)
                return;
        while (head->r.step < TOMOYO_MAX_POLICY + TOMOYO_MAX_GROUP &&
               tomoyo_read_group(head, head->r.step - TOMOYO_MAX_POLICY))
                head->r.step++;
        if (head->r.step < TOMOYO_MAX_POLICY + TOMOYO_MAX_GROUP)
                return;
        while (head->r.step < TOMOYO_MAX_POLICY + TOMOYO_MAX_GROUP
               + TOMOYO_MAX_ACL_GROUPS) {
                head->r.acl_group_index = head->r.step - TOMOYO_MAX_POLICY
                        - TOMOYO_MAX_GROUP;
                if (!tomoyo_read_domain2(head, &ns->acl_group
                                         [head->r.acl_group_index]))
                        return;
                head->r.step++;
        }
        head->r.eof = true;
}

/* Wait queue for kernel -> userspace notification. */
static DECLARE_WAIT_QUEUE_HEAD(tomoyo_query_wait);
/* Wait queue for userspace -> kernel notification. */
static DECLARE_WAIT_QUEUE_HEAD(tomoyo_answer_wait);

/* Structure for query. */
struct tomoyo_query {
        struct list_head list;
        char *query;
        size_t query_len;
        unsigned int serial;
        u8 timer;
        u8 answer;
        u8 retry;
};

/* The list for "struct tomoyo_query". */
static LIST_HEAD(tomoyo_query_list);

/* Lock for manipulating tomoyo_query_list. */
static DEFINE_SPINLOCK(tomoyo_query_list_lock);

/*
 * Number of "struct file" referring /sys/kernel/security/tomoyo/query
 * interface.
 */
static atomic_t tomoyo_query_observers = ATOMIC_INIT(0);

/**
 * tomoyo_add_entry - Add an ACL to current thread's domain. Used by learning mode.
 *
 * @domain: Pointer to "struct tomoyo_domain_info".
 * @header: Lines containing ACL.
 *
 * Returns nothing.
 */
static void tomoyo_add_entry(struct tomoyo_domain_info *domain, char *header)
{
        char *buffer;
        char *cp = strchr(header, '\n');
        int len;
        if (!cp)
                return;
        cp = strchr(cp + 1, '\n');
        if (!cp)
                return;
        *cp++ = '\0';
        len = strlen(cp) + 1;
        buffer = kmalloc(len, GFP_NOFS);
        if (!buffer)
                return;
        snprintf(buffer, len - 1, "%s", cp);
        tomoyo_normalize_line(buffer);
        if (!tomoyo_write_domain2(domain->ns, &domain->acl_info_list, buffer,
                                  false))
                tomoyo_update_stat(TOMOYO_STAT_POLICY_UPDATES);
        kfree(buffer);
}

/**
 * tomoyo_supervisor - Ask for the supervisor's decision.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @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, TOMOYO_RETRY_REQUEST if the
 * supervisor decided to retry the access request which violated the policy in
 * enforcing mode, 0 if it is not in enforcing mode, -EPERM otherwise.
 */
int tomoyo_supervisor(struct tomoyo_request_info *r, const char *fmt, ...)
{
        va_list args;
        int error;
        int len;
        static unsigned int tomoyo_serial;
        struct tomoyo_query entry = { };
        bool quota_exceeded = false;
        va_start(args, fmt);
        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
        va_end(args);
        /* Write /sys/kernel/security/tomoyo/audit. */
        va_start(args, fmt);
        tomoyo_write_log2(r, len, fmt, args);
        va_end(args);
        /* Nothing more to do if granted. */
        if (r->granted)
                return 0;
        if (r->mode)
                tomoyo_update_stat(r->mode);
        switch (r->mode) {
        case TOMOYO_CONFIG_ENFORCING:
                error = -EPERM;
                if (atomic_read(&tomoyo_query_observers))
                        break;
                goto out;
        case TOMOYO_CONFIG_LEARNING:
                error = 0;
                /* Check max_learning_entry parameter. */
                if (tomoyo_domain_quota_is_ok(r))
                        break;
                /* fall through */
        default:
                return 0;
        }
        /* Get message. */
        va_start(args, fmt);
        entry.query = tomoyo_init_log(r, len, fmt, args);
        va_end(args);
        if (!entry.query)
                goto out;
        entry.query_len = strlen(entry.query) + 1;
        if (!error) {
                tomoyo_add_entry(r->domain, entry.query);
                goto out;
        }
        len = tomoyo_round2(entry.query_len);
        spin_lock(&tomoyo_query_list_lock);
        if (tomoyo_memory_quota[TOMOYO_MEMORY_QUERY] &&
            tomoyo_memory_used[TOMOYO_MEMORY_QUERY] + len
            >= tomoyo_memory_quota[TOMOYO_MEMORY_QUERY]) {
                quota_exceeded = true;
        } else {
                entry.serial = tomoyo_serial++;
                entry.retry = r->retry;
                tomoyo_memory_used[TOMOYO_MEMORY_QUERY] += len;
                list_add_tail(&entry.list, &tomoyo_query_list);
        }
        spin_unlock(&tomoyo_query_list_lock);
        if (quota_exceeded)
                goto out;
        /* Give 10 seconds for supervisor's opinion. */
        while (entry.timer < 10) {
                wake_up_all(&tomoyo_query_wait);
                if (wait_event_interruptible_timeout
                    (tomoyo_answer_wait, entry.answer ||
                     !atomic_read(&tomoyo_query_observers), HZ))
                        break;
                else
                        entry.timer++;
        }
        spin_lock(&tomoyo_query_list_lock);
        list_del(&entry.list);
        tomoyo_memory_used[TOMOYO_MEMORY_QUERY] -= len;
        spin_unlock(&tomoyo_query_list_lock);
        switch (entry.answer) {
        case 3: /* Asked to retry by administrator. */
                error = TOMOYO_RETRY_REQUEST;
                r->retry++;
                break;
        case 1:
                /* Granted by administrator. */
                error = 0;
                break;
        default:
                /* Timed out or rejected by administrator. */
                break;
        }
out:
        kfree(entry.query);
        return error;
}

/**
 * tomoyo_poll_query - poll() for /sys/kernel/security/tomoyo/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 tomoyo_poll_query(struct file *file, poll_table *wait)
{
        struct list_head *tmp;
        bool found = false;
        u8 i;
        for (i = 0; i < 2; i++) {
                spin_lock(&tomoyo_query_list_lock);
                list_for_each(tmp, &tomoyo_query_list) {
                        struct tomoyo_query *ptr =
                                list_entry(tmp, typeof(*ptr), list);
                        if (ptr->answer)
                                continue;
                        found = true;
                        break;
                }
                spin_unlock(&tomoyo_query_list_lock);
                if (found)
                        return POLLIN | POLLRDNORM;
                if (i)
                        break;
                poll_wait(file, &tomoyo_query_wait, wait);
        }
        return 0;
}

/**
 * tomoyo_read_query - Read access requests which violated policy in enforcing mode.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 */
static void tomoyo_read_query(struct tomoyo_io_buffer *head)
{
        struct list_head *tmp;
        unsigned int pos = 0;
        size_t len = 0;
        char *buf;
        if (head->r.w_pos)
                return;
        if (head->read_buf) {
                kfree(head->read_buf);
                head->read_buf = NULL;
        }
        spin_lock(&tomoyo_query_list_lock);
        list_for_each(tmp, &tomoyo_query_list) {
                struct tomoyo_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->answer)
                        continue;
                if (pos++ != head->r.query_index)
                        continue;
                len = ptr->query_len;
                break;
        }
        spin_unlock(&tomoyo_query_list_lock);
        if (!len) {
                head->r.query_index = 0;
                return;
        }
        buf = kzalloc(len + 32, GFP_NOFS);
        if (!buf)
                return;
        pos = 0;
        spin_lock(&tomoyo_query_list_lock);
        list_for_each(tmp, &tomoyo_query_list) {
                struct tomoyo_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->answer)
                        continue;
                if (pos++ != head->r.query_index)
                        continue;
                /*
                 * Some query can be skipped because tomoyo_query_list
                 * can change, but I don't care.
                 */
                if (len == ptr->query_len)
                        snprintf(buf, len + 31, "Q%u-%hu\n%s", ptr->serial,
                                 ptr->retry, ptr->query);
                break;
        }
        spin_unlock(&tomoyo_query_list_lock);
        if (buf[0]) {
                head->read_buf = buf;
                head->r.w[head->r.w_pos++] = buf;
                head->r.query_index++;
        } else {
                kfree(buf);
        }
}

/**
 * tomoyo_write_answer - Write the supervisor's decision.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 */
static int tomoyo_write_answer(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;
        struct list_head *tmp;
        unsigned int serial;
        unsigned int answer;
        spin_lock(&tomoyo_query_list_lock);
        list_for_each(tmp, &tomoyo_query_list) {
                struct tomoyo_query *ptr = list_entry(tmp, typeof(*ptr), list);
                ptr->timer = 0;
        }
        spin_unlock(&tomoyo_query_list_lock);
        if (sscanf(data, "A%u=%u", &serial, &answer) != 2)
                return -EINVAL;
        spin_lock(&tomoyo_query_list_lock);
        list_for_each(tmp, &tomoyo_query_list) {
                struct tomoyo_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->serial != serial)
                        continue;
                if (!ptr->answer)
                        ptr->answer = answer;
                break;
        }
        spin_unlock(&tomoyo_query_list_lock);
        return 0;
}

/**
 * tomoyo_read_version: Get version.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns version information.
 */
static void tomoyo_read_version(struct tomoyo_io_buffer *head)
{
        if (!head->r.eof) {
                tomoyo_io_printf(head, "2.4.0");
                head->r.eof = true;
        }
}

/**
 * tomoyo_read_self_domain - Get the current process's domainname.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns the current process's domainname.
 */
static void tomoyo_read_self_domain(struct tomoyo_io_buffer *head)
{
        if (!head->r.eof) {
                /*
                 * tomoyo_domain()->domainname != NULL
                 * because every process belongs to a domain and
                 * the domain's name cannot be NULL.
                 */
                tomoyo_io_printf(head, "%s", tomoyo_domain()->domainname->name);
                head->r.eof = true;
        }
}

/* String table for /sys/kernel/security/tomoyo/stat interface. */
static const char * const tomoyo_policy_headers[TOMOYO_MAX_POLICY_STAT] = {
        [TOMOYO_STAT_POLICY_UPDATES]    = "update:",
        [TOMOYO_STAT_POLICY_LEARNING]   = "violation in learning mode:",
        [TOMOYO_STAT_POLICY_PERMISSIVE] = "violation in permissive mode:",
        [TOMOYO_STAT_POLICY_ENFORCING]  = "violation in enforcing mode:",
};

/* String table for /sys/kernel/security/tomoyo/stat interface. */
static const char * const tomoyo_memory_headers[TOMOYO_MAX_MEMORY_STAT] = {
        [TOMOYO_MEMORY_POLICY] = "policy:",
        [TOMOYO_MEMORY_AUDIT]  = "audit log:",
        [TOMOYO_MEMORY_QUERY]  = "query message:",
};

/* Timestamp counter for last updated. */
static unsigned int tomoyo_stat_updated[TOMOYO_MAX_POLICY_STAT];
/* Counter for number of updates. */
static unsigned int tomoyo_stat_modified[TOMOYO_MAX_POLICY_STAT];

/**
 * tomoyo_update_stat - Update statistic counters.
 *
 * @index: Index for policy type.
 *
 * Returns nothing.
 */
void tomoyo_update_stat(const u8 index)
{
        struct timeval tv;
        do_gettimeofday(&tv);
        /*
         * I don't use atomic operations because race condition is not fatal.
         */
        tomoyo_stat_updated[index]++;
        tomoyo_stat_modified[index] = tv.tv_sec;
}

/**
 * tomoyo_read_stat - Read statistic data.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static void tomoyo_read_stat(struct tomoyo_io_buffer *head)
{
        u8 i;
        unsigned int total = 0;
        if (head->r.eof)
                return;
        for (i = 0; i < TOMOYO_MAX_POLICY_STAT; i++) {
                tomoyo_io_printf(head, "Policy %-30s %10u",
                                 tomoyo_policy_headers[i],
                                 tomoyo_stat_updated[i]);
                if (tomoyo_stat_modified[i]) {
                        struct tomoyo_time stamp;
                        tomoyo_convert_time(tomoyo_stat_modified[i], &stamp);
                        tomoyo_io_printf(head, " (Last: %04u/%02u/%02u "
                                         "%02u:%02u:%02u)",
                                         stamp.year, stamp.month, stamp.day,
                                         stamp.hour, stamp.min, stamp.sec);
                }
                tomoyo_set_lf(head);
        }
        for (i = 0; i < TOMOYO_MAX_MEMORY_STAT; i++) {
                unsigned int used = tomoyo_memory_used[i];
                total += used;
                tomoyo_io_printf(head, "Memory used by %-22s %10u",
                                 tomoyo_memory_headers[i], used);
                used = tomoyo_memory_quota[i];
                if (used)
                        tomoyo_io_printf(head, " (Quota: %10u)", used);
                tomoyo_set_lf(head);
        }
        tomoyo_io_printf(head, "Total memory used:                    %10u\n",
                         total);
        head->r.eof = true;
}

/**
 * tomoyo_write_stat - Set memory quota.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0.
 */
static int tomoyo_write_stat(struct tomoyo_io_buffer *head)
{
        char *data = head->write_buf;
        u8 i;
        if (tomoyo_str_starts(&data, "Memory used by "))
                for (i = 0; i < TOMOYO_MAX_MEMORY_STAT; i++)
                        if (tomoyo_str_starts(&data, tomoyo_memory_headers[i]))
                                sscanf(data, "%u", &tomoyo_memory_quota[i]);
        return 0;
}

/**
 * tomoyo_open_control - open() for /sys/kernel/security/tomoyo/ interface.
 *
 * @type: Type of interface.
 * @file: Pointer to "struct file".
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_open_control(const u8 type, struct file *file)
{
        struct tomoyo_io_buffer *head = kzalloc(sizeof(*head), GFP_NOFS);

        if (!head)
                return -ENOMEM;
        mutex_init(&head->io_sem);
        head->type = type;
        switch (type) {
        case TOMOYO_DOMAINPOLICY:
                /* /sys/kernel/security/tomoyo/domain_policy */
                head->write = tomoyo_write_domain;
                head->read = tomoyo_read_domain;
                break;
        case TOMOYO_EXCEPTIONPOLICY:
                /* /sys/kernel/security/tomoyo/exception_policy */
                head->write = tomoyo_write_exception;
                head->read = tomoyo_read_exception;
                break;
        case TOMOYO_AUDIT:
                /* /sys/kernel/security/tomoyo/audit */
                head->poll = tomoyo_poll_log;
                head->read = tomoyo_read_log;
                break;
        case TOMOYO_SELFDOMAIN:
                /* /sys/kernel/security/tomoyo/self_domain */
                head->read = tomoyo_read_self_domain;
                break;
        case TOMOYO_DOMAIN_STATUS:
                /* /sys/kernel/security/tomoyo/.domain_status */
                head->write = tomoyo_write_domain_profile;
                head->read = tomoyo_read_domain_profile;
                break;
        case TOMOYO_PROCESS_STATUS:
                /* /sys/kernel/security/tomoyo/.process_status */
                head->write = tomoyo_write_pid;
                head->read = tomoyo_read_pid;
                break;
        case TOMOYO_VERSION:
                /* /sys/kernel/security/tomoyo/version */
                head->read = tomoyo_read_version;
                head->readbuf_size = 128;
                break;
        case TOMOYO_STAT:
                /* /sys/kernel/security/tomoyo/stat */
                head->write = tomoyo_write_stat;
                head->read = tomoyo_read_stat;
                head->readbuf_size = 1024;
                break;
        case TOMOYO_PROFILE:
                /* /sys/kernel/security/tomoyo/profile */
                head->write = tomoyo_write_profile;
                head->read = tomoyo_read_profile;
                break;
        case TOMOYO_QUERY: /* /sys/kernel/security/tomoyo/query */
                head->poll = tomoyo_poll_query;
                head->write = tomoyo_write_answer;
                head->read = tomoyo_read_query;
                break;
        case TOMOYO_MANAGER:
                /* /sys/kernel/security/tomoyo/manager */
                head->write = tomoyo_write_manager;
                head->read = tomoyo_read_manager;
                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 (!head->poll) {
                /* Don't allocate read_buf for poll() access. */
                if (!head->readbuf_size)
                        head->readbuf_size = 4096 * 2;
                head->read_buf = kzalloc(head->readbuf_size, GFP_NOFS);
                if (!head->read_buf) {
                        kfree(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 = kzalloc(head->writebuf_size, GFP_NOFS);
                if (!head->write_buf) {
                        kfree(head->read_buf);
                        kfree(head);
                        return -ENOMEM;
                }
        }
        /*
         * If the file is /sys/kernel/security/tomoyo/query , increment the
         * observer counter.
         * The obserber counter is used by tomoyo_supervisor() to see if
         * there is some process monitoring /sys/kernel/security/tomoyo/query.
         */
        if (type == TOMOYO_QUERY)
                atomic_inc(&tomoyo_query_observers);
        file->private_data = head;
        tomoyo_notify_gc(head, true);
        return 0;
}

/**
 * tomoyo_poll_control - poll() for /sys/kernel/security/tomoyo/ interface.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Waits for read readiness.
 * /sys/kernel/security/tomoyo/query is handled by /usr/sbin/tomoyo-queryd and
 * /sys/kernel/security/tomoyo/audit is handled by /usr/sbin/tomoyo-auditd.
 */
int tomoyo_poll_control(struct file *file, poll_table *wait)
{
        struct tomoyo_io_buffer *head = file->private_data;
        if (!head->poll)
                return -ENOSYS;
        return head->poll(file, wait);
}

/**
 * tomoyo_set_namespace_cursor - Set namespace to read.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
static inline void tomoyo_set_namespace_cursor(struct tomoyo_io_buffer *head)
{
        struct list_head *ns;
        if (head->type != TOMOYO_EXCEPTIONPOLICY &&
            head->type != TOMOYO_PROFILE)
                return;
        /*
         * If this is the first read, or reading previous namespace finished
         * and has more namespaces to read, update the namespace cursor.
         */
        ns = head->r.ns;
        if (!ns || (head->r.eof && ns->next != &tomoyo_namespace_list)) {
                /* Clearing is OK because tomoyo_flush() returned true. */
                memset(&head->r, 0, sizeof(head->r));
                head->r.ns = ns ? ns->next : tomoyo_namespace_list.next;
        }
}

/**
 * tomoyo_has_more_namespace - Check for unread namespaces.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns true if we have more entries to print, false otherwise.
 */
static inline bool tomoyo_has_more_namespace(struct tomoyo_io_buffer *head)
{
        return (head->type == TOMOYO_EXCEPTIONPOLICY ||
                head->type == TOMOYO_PROFILE) && head->r.eof &&
                head->r.ns->next != &tomoyo_namespace_list;
}

/**
 * tomoyo_read_control - read() for /sys/kernel/security/tomoyo/ interface.
 *
 * @head:       Pointer to "struct tomoyo_io_buffer".
 * @buffer:     Poiner to buffer to write to.
 * @buffer_len: Size of @buffer.
 *
 * Returns bytes read on success, negative value otherwise.
 */
ssize_t tomoyo_read_control(struct tomoyo_io_buffer *head, char __user *buffer,
                            const int buffer_len)
{
        int len;
        int idx;

        if (!head->read)
                return -ENOSYS;
        if (mutex_lock_interruptible(&head->io_sem))
                return -EINTR;
        head->read_user_buf = buffer;
        head->read_user_buf_avail = buffer_len;
        idx = tomoyo_read_lock();
        if (tomoyo_flush(head))
                /* Call the policy handler. */
                do {
                        tomoyo_set_namespace_cursor(head);
                        head->read(head);
                } while (tomoyo_flush(head) &&
                         tomoyo_has_more_namespace(head));
        tomoyo_read_unlock(idx);
        len = head->read_user_buf - buffer;
        mutex_unlock(&head->io_sem);
        return len;
}

/**
 * tomoyo_parse_policy - Parse a policy line.
 *
 * @head: Poiter to "struct tomoyo_io_buffer".
 * @line: Line to parse.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_parse_policy(struct tomoyo_io_buffer *head, char *line)
{
        /* Delete request? */
        head->w.is_delete = !strncmp(line, "delete ", 7);
        if (head->w.is_delete)
                memmove(line, line + 7, strlen(line + 7) + 1);
        /* Selecting namespace to update. */
        if (head->type == TOMOYO_EXCEPTIONPOLICY ||
            head->type == TOMOYO_PROFILE) {
                if (*line == '<') {
                        char *cp = strchr(line, ' ');
                        if (cp) {
                                *cp++ = '\0';
                                head->w.ns = tomoyo_assign_namespace(line);
                                memmove(line, cp, strlen(cp) + 1);
                        } else
                                head->w.ns = NULL;
                } else
                        head->w.ns = &tomoyo_kernel_namespace;
                /* Don't allow updating if namespace is invalid. */
                if (!head->w.ns)
                        return -ENOENT;
        }
        /* Do the update. */
        return head->write(head);
}

/**
 * tomoyo_write_control - write() for /sys/kernel/security/tomoyo/ interface.
 *
 * @head:       Pointer to "struct tomoyo_io_buffer".
 * @buffer:     Pointer to buffer to read from.
 * @buffer_len: Size of @buffer.
 *
 * Returns @buffer_len on success, negative value otherwise.
 */
ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head,
                             const char __user *buffer, const int buffer_len)
{
        int error = buffer_len;
        size_t avail_len = buffer_len;
        char *cp0 = head->write_buf;
        int idx;
        if (!head->write)
                return -ENOSYS;
        if (!access_ok(VERIFY_READ, buffer, buffer_len))
                return -EFAULT;
        if (mutex_lock_interruptible(&head->io_sem))
                return -EINTR;
        idx = tomoyo_read_lock();
        /* Read a line and dispatch it to the policy handler. */
        while (avail_len > 0) {
                char c;
                if (head->w.avail >= head->writebuf_size - 1) {
                        const int len = head->writebuf_size * 2;
                        char *cp = kzalloc(len, GFP_NOFS);
                        if (!cp) {
                                error = -ENOMEM;
                                break;
                        }
                        memmove(cp, cp0, head->w.avail);
                        kfree(cp0);
                        head->write_buf = cp;
                        cp0 = cp;
                        head->writebuf_size = len;
                }
                if (get_user(c, buffer)) {
                        error = -EFAULT;
                        break;
                }
                buffer++;
                avail_len--;
                cp0[head->w.avail++] = c;
                if (c != '\n')
                        continue;
                cp0[head->w.avail - 1] = '\0';
                head->w.avail = 0;
                tomoyo_normalize_line(cp0);
                if (!strcmp(cp0, "reset")) {
                        head->w.ns = &tomoyo_kernel_namespace;
                        head->w.domain = NULL;
                        memset(&head->r, 0, sizeof(head->r));
                        continue;
                }
                /* Don't allow updating policies by non manager programs. */
                switch (head->type) {
                case TOMOYO_PROCESS_STATUS:
                        /* This does not write anything. */
                        break;
                case TOMOYO_DOMAINPOLICY:
                        if (tomoyo_select_domain(head, cp0))
                                continue;
                        /* fall through */
                case TOMOYO_EXCEPTIONPOLICY:
                        if (!strcmp(cp0, "select transition_only")) {
                                head->r.print_transition_related_only = true;
                                continue;
                        }
                        /* fall through */
                default:
                        if (!tomoyo_manager()) {
                                error = -EPERM;
                                goto out;
                        }
                }
                switch (tomoyo_parse_policy(head, cp0)) {
                case -EPERM:
                        error = -EPERM;
                        goto out;
                case 0:
                        switch (head->type) {
                        case TOMOYO_DOMAINPOLICY:
                        case TOMOYO_EXCEPTIONPOLICY:
                        case TOMOYO_DOMAIN_STATUS:
                        case TOMOYO_STAT:
                        case TOMOYO_PROFILE:
                        case TOMOYO_MANAGER:
                                tomoyo_update_stat(TOMOYO_STAT_POLICY_UPDATES);
                                break;
                        default:
                                break;
                        }
                        break;
                }
        }
out:
        tomoyo_read_unlock(idx);
        mutex_unlock(&head->io_sem);
        return error;
}

/**
 * tomoyo_close_control - close() for /sys/kernel/security/tomoyo/ interface.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns 0.
 */
int tomoyo_close_control(struct tomoyo_io_buffer *head)
{
        /*
         * If the file is /sys/kernel/security/tomoyo/query , decrement the
         * observer counter.
         */
        if (head->type == TOMOYO_QUERY &&
            atomic_dec_and_test(&tomoyo_query_observers))
                wake_up_all(&tomoyo_answer_wait);
        tomoyo_notify_gc(head, false);
        return 0;
}

/**
 * tomoyo_check_profile - Check all profiles currently assigned to domains are defined.
 */
void tomoyo_check_profile(void)
{
        struct tomoyo_domain_info *domain;
        const int idx = tomoyo_read_lock();
        tomoyo_policy_loaded = true;
        printk(KERN_INFO "TOMOYO: 2.4.0\n");
        list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
                const u8 profile = domain->profile;
                const struct tomoyo_policy_namespace *ns = domain->ns;
                if (ns->profile_version != 20100903)
                        printk(KERN_ERR
                               "Profile version %u is not supported.\n",
                               ns->profile_version);
                else if (!ns->profile_ptr[profile])
                        printk(KERN_ERR
                               "Profile %u (used by '%s') is not defined.\n",
                               profile, domain->domainname->name);
                else
                        continue;
                printk(KERN_ERR
                       "Userland tools for TOMOYO 2.4 must be installed and "
                       "policy must be initialized.\n");
                printk(KERN_ERR "Please see http://tomoyo.sourceforge.jp/2.4/ "
                       "for more information.\n");
                panic("STOP!");
        }
        tomoyo_read_unlock(idx);
        printk(KERN_INFO "Mandatory Access Control activated.\n");
}

/**
 * tomoyo_load_builtin_policy - Load built-in policy.
 *
 * Returns nothing.
 */
void __init tomoyo_load_builtin_policy(void)
{
        /*
         * This include file is manually created and contains built-in policy
         * named "tomoyo_builtin_profile", "tomoyo_builtin_exception_policy",
         * "tomoyo_builtin_domain_policy", "tomoyo_builtin_manager",
         * "tomoyo_builtin_stat" in the form of "static char [] __initdata".
         */
#include "builtin-policy.h"
        u8 i;
        const int idx = tomoyo_read_lock();
        for (i = 0; i < 5; i++) {
                struct tomoyo_io_buffer head = { };
                char *start = "";
                switch (i) {
                case 0:
                        start = tomoyo_builtin_profile;
                        head.type = TOMOYO_PROFILE;
                        head.write = tomoyo_write_profile;
                        break;
                case 1:
                        start = tomoyo_builtin_exception_policy;
                        head.type = TOMOYO_EXCEPTIONPOLICY;
                        head.write = tomoyo_write_exception;
                        break;
                case 2:
                        start = tomoyo_builtin_domain_policy;
                        head.type = TOMOYO_DOMAINPOLICY;
                        head.write = tomoyo_write_domain;
                        break;
                case 3:
                        start = tomoyo_builtin_manager;
                        head.type = TOMOYO_MANAGER;
                        head.write = tomoyo_write_manager;
                        break;
                case 4:
                        start = tomoyo_builtin_stat;
                        head.type = TOMOYO_STAT;
                        head.write = tomoyo_write_stat;
                        break;
                }
                while (1) {
                        char *end = strchr(start, '\n');
                        if (!end)
                                break;
                        *end = '\0';
                        tomoyo_normalize_line(start);
                        head.write_buf = start;
                        tomoyo_parse_policy(&head, start);
                        start = end + 1;
                }
        }
        tomoyo_read_unlock(idx);
#ifdef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
        tomoyo_check_profile();
#endif
}