/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2014 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <sys/mman.h>

#include "set.h"
#include "util.h"
#include "utf8.h"
#include "strv.h"

#include "locale-util.h"

static int add_locales_from_archive(Set *locales) {
        /* Stolen from glibc... */

        struct locarhead {
                uint32_t magic;
                /* Serial number.  */
                uint32_t serial;
                /* Name hash table.  */
                uint32_t namehash_offset;
                uint32_t namehash_used;
                uint32_t namehash_size;
                /* String table.  */
                uint32_t string_offset;
                uint32_t string_used;
                uint32_t string_size;
                /* Table with locale records.  */
                uint32_t locrectab_offset;
                uint32_t locrectab_used;
                uint32_t locrectab_size;
                /* MD5 sum hash table.  */
                uint32_t sumhash_offset;
                uint32_t sumhash_used;
                uint32_t sumhash_size;
        };

        struct namehashent {
                /* Hash value of the name.  */
                uint32_t hashval;
                /* Offset of the name in the string table.  */
                uint32_t name_offset;
                /* Offset of the locale record.  */
                uint32_t locrec_offset;
        };

        const struct locarhead *h;
        const struct namehashent *e;
        const void *p = MAP_FAILED;
        _cleanup_close_ int fd = -1;
        size_t sz = 0;
        struct stat st;
        unsigned i;
        int r;

        fd = open("/usr/lib/locale/locale-archive", O_RDONLY|O_NOCTTY|O_CLOEXEC);
        if (fd < 0)
                return errno == ENOENT ? 0 : -errno;

        if (fstat(fd, &st) < 0)
                return -errno;

        if (!S_ISREG(st.st_mode))
                return -EBADMSG;

        if (st.st_size < (off_t) sizeof(struct locarhead))
                return -EBADMSG;

        p = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
        if (p == MAP_FAILED)
                return -errno;

        h = (const struct locarhead *) p;
        if (h->magic != 0xde020109 ||
            h->namehash_offset + h->namehash_size > st.st_size ||
            h->string_offset + h->string_size > st.st_size ||
            h->locrectab_offset + h->locrectab_size > st.st_size ||
            h->sumhash_offset + h->sumhash_size > st.st_size) {
                r = -EBADMSG;
                goto finish;
        }

        e = (const struct namehashent*) ((const uint8_t*) p + h->namehash_offset);
        for (i = 0; i < h->namehash_size; i++) {
                char *z;

                if (e[i].locrec_offset == 0)
                        continue;

                if (!utf8_is_valid((char*) p + e[i].name_offset))
                        continue;

                z = strdup((char*) p + e[i].name_offset);
                if (!z) {
                        r = -ENOMEM;
                        goto finish;
                }

                r = set_consume(locales, z);
                if (r < 0)
                        goto finish;
        }

        r = 0;

 finish:
        if (p != MAP_FAILED)
                munmap((void*) p, sz);

        return r;
}

static int add_locales_from_libdir (Set *locales) {
        _cleanup_closedir_ DIR *dir = NULL;
        struct dirent *entry;
        int r;

        dir = opendir("/usr/lib/locale");
        if (!dir)
                return errno == ENOENT ? 0 : -errno;

        FOREACH_DIRENT(entry, dir, return -errno) {
                char *z;

                if (entry->d_type != DT_DIR)
                        continue;

                z = strdup(entry->d_name);
                if (!z)
                        return -ENOMEM;

                r = set_consume(locales, z);
                if (r < 0 && r != -EEXIST)
                        return r;
        }

        return 0;
}

int get_locales(char ***ret) {
        _cleanup_set_free_ Set *locales = NULL;
        _cleanup_strv_free_ char **l = NULL;
        int r;

        locales = set_new(&string_hash_ops);
        if (!locales)
                return -ENOMEM;

        r = add_locales_from_archive(locales);
        if (r < 0 && r != -ENOENT)
                return r;

        r = add_locales_from_libdir(locales);
        if (r < 0)
                return r;

        l = set_get_strv(locales);
        if (!l)
                return -ENOMEM;

        strv_sort(l);

        *ret = l;
        l = NULL;

        return 0;
}

bool locale_is_valid(const char *name) {

        if (isempty(name))
                return false;

        if (strlen(name) >= 128)
                return false;

        if (!utf8_is_valid(name))
                return false;

        if (!filename_is_safe(name))
                return false;

        if (!string_is_safe(name))
                return false;

        return true;
}