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

/***
  This file is part of systemd.

  Copyright 2012 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 <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/mman.h>
#include <locale.h>

#include "util.h"
#include "log.h"
#include "sparse-endian.h"
#include "sd-id128.h"
#include "hashmap.h"
#include "strv.h"
#include "strbuf.h"
#include "conf-files.h"
#include "mkdir.h"
#include "catalog.h"

static const char * const conf_file_dirs[] = {
        "/usr/local/lib/systemd/catalog/",
        "/usr/lib/systemd/catalog/",
        NULL
};

#define CATALOG_SIGNATURE (uint8_t[]) { 'R', 'H', 'H', 'H', 'K', 'S', 'L', 'P' }

typedef struct CatalogHeader {
        uint8_t signature[8];  /* "RHHHKSLP" */
        le32_t compatible_flags;
        le32_t incompatible_flags;
        le64_t header_size;
        le64_t n_items;
        le64_t catalog_item_size;
} CatalogHeader;

typedef struct CatalogItem {
        sd_id128_t id;
        char language[32];
        le64_t offset;
} CatalogItem;

static unsigned catalog_hash_func(const void *p) {
        const CatalogItem *i = p;

        assert_cc(sizeof(unsigned) == sizeof(uint8_t)*4);

        return (((unsigned) i->id.bytes[0] << 24) |
                ((unsigned) i->id.bytes[1] << 16) |
                ((unsigned) i->id.bytes[2] << 8) |
                ((unsigned) i->id.bytes[3])) ^
               (((unsigned) i->id.bytes[4] << 24) |
                ((unsigned) i->id.bytes[5] << 16) |
                ((unsigned) i->id.bytes[6] << 8) |
                ((unsigned) i->id.bytes[7])) ^
               (((unsigned) i->id.bytes[8] << 24) |
                ((unsigned) i->id.bytes[9] << 16) |
                ((unsigned) i->id.bytes[10] << 8) |
                ((unsigned) i->id.bytes[11])) ^
               (((unsigned) i->id.bytes[12] << 24) |
                ((unsigned) i->id.bytes[13] << 16) |
                ((unsigned) i->id.bytes[14] << 8) |
                ((unsigned) i->id.bytes[15])) ^
                string_hash_func(i->language);
}

static int catalog_compare_func(const void *a, const void *b) {
        const CatalogItem *i = a, *j = b;
        unsigned k;

        for (k = 0; k < ELEMENTSOF(j->id.bytes); k++) {
                 if (i->id.bytes[k] < j->id.bytes[k])
                        return -1;
                 if (i->id.bytes[k] > j->id.bytes[k])
                        return 1;
        }

        return strncmp(i->language, j->language, sizeof(i->language));
}

static int finish_item(
                Hashmap *h,
                struct strbuf *sb,
                sd_id128_t id,
                const char *language,
                const char *payload) {

        ssize_t offset;
        CatalogItem *i;
        int r;

        assert(h);
        assert(sb);
        assert(payload);

        offset = strbuf_add_string(sb, payload, strlen(payload));
        if (offset < 0)
                return log_oom();

        i = new0(CatalogItem, 1);
        if (!i)
                return log_oom();

        i->id = id;
        strncpy(i->language, language, sizeof(i->language));
        i->offset = htole64((uint64_t) offset);

        r = hashmap_put(h, i, i);
        if (r == EEXIST) {
                log_warning("Duplicate entry for " SD_ID128_FORMAT_STR ".%s, ignoring.", SD_ID128_FORMAT_VAL(id), language ? language : "C");
                free(i);
                return 0;
        }

        return 0;
}

static int import_file(Hashmap *h, struct strbuf *sb, const char *path) {
        _cleanup_fclose_ FILE *f = NULL;
        _cleanup_free_ char *payload = NULL;
        unsigned n = 0;
        sd_id128_t id;
        char language[32];
        bool got_id = false, empty_line = true;
        int r;

        assert(h);
        assert(sb);
        assert(path);

        f = fopen(path, "re");
        if (!f) {
                log_error("Failed to open file %s: %m", path);
                return -errno;
        }

        for (;;) {
                char line[LINE_MAX];
                size_t a, b, c;
                char *t;

                if (!fgets(line, sizeof(line), f)) {
                        if (feof(f))
                                break;

                        log_error("Failed to read file %s: %m", path);
                        return -errno;
                }

                n++;

                truncate_nl(line);

                if (line[0] == 0) {
                        empty_line = true;
                        continue;
                }

                if (strchr(COMMENTS, line[0]))
                        continue;

                if (empty_line &&
                    strlen(line) >= 2+1+32 &&
                    line[0] == '-' &&
                    line[1] == '-' &&
                    line[2] == ' ' &&
                    (line[2+1+32] == ' ' || line[2+1+32] == 0)) {

                        bool with_language;
                        sd_id128_t jd;

                        /* New entry */

                        with_language = line[2+1+32] != 0;
                        line[2+1+32] = 0;

                        if (sd_id128_from_string(line + 2 + 1, &jd) >= 0) {

                                if (got_id) {
                                        r = finish_item(h, sb, id, language, payload);
                                        if (r < 0)
                                                return r;
                                }

                                if (with_language) {
                                        t = strstrip(line + 2 + 1 + 32 + 1);

                                        c = strlen(t);
                                        if (c <= 0) {
                                                log_error("[%s:%u] Language too short.", path, n);
                                                return -EINVAL;
                                        }
                                        if (c > sizeof(language)) {
                                                log_error("[%s:%u] language too long.", path, n);
                                                return -EINVAL;
                                        }

                                        strncpy(language, t, sizeof(language));
                                } else
                                        zero(language);

                                got_id = true;
                                empty_line = false;
                                id = jd;

                                if (payload)
                                        payload[0] = 0;

                                continue;
                        }
                }

                /* Payload */
                if (!got_id) {
                        log_error("[%s:%u] Got payload before ID.", path, n);
                        return -EINVAL;
                }

                a = payload ? strlen(payload) : 0;
                b = strlen(line);

                c = a + (empty_line ? 1 : 0) + b + 1 + 1;
                t = realloc(payload, c);
                if (!t)
                        return log_oom();

                if (empty_line) {
                        t[a] = '\n';
                        memcpy(t + a + 1, line, b);
                        t[a+b+1] = '\n';
                        t[a+b+2] = 0;
                } else {
                        memcpy(t + a, line, b);
                        t[a+b] = '\n';
                        t[a+b+1] = 0;
                }

                payload = t;
                empty_line = false;
        }

        if (got_id) {
                r = finish_item(h, sb, id, language, payload);
                if (r < 0)
                        return r;
        }

        return 0;
}

#define CATALOG_PATH "/var/lib/systemd/catalog"
#define CATALOG_DATABASE CATALOG_PATH "/database"

int catalog_update(void) {
        _cleanup_strv_free_ char **files = NULL;
        _cleanup_fclose_ FILE *w = NULL;
        _cleanup_free_ char *p = NULL;
        char **f;
        Hashmap *h;
        struct strbuf *sb = NULL;
        _cleanup_free_ CatalogItem *items = NULL;
        CatalogItem *i;
        CatalogHeader header;
        size_t k;
        Iterator j;
        unsigned n;
        int r;

        h = hashmap_new(catalog_hash_func, catalog_compare_func);
        if (!h)
                return -ENOMEM;

        sb = strbuf_new();
        if (!sb) {
                r = log_oom();
                goto finish;
        }

        r = conf_files_list_strv(&files, ".catalog", (const char **) conf_file_dirs);
        if (r < 0) {
                log_error("Failed to get catalog files: %s", strerror(-r));
                goto finish;
        }

        STRV_FOREACH(f, files) {
                log_debug("reading file '%s'", *f);
                import_file(h, sb, *f);
        }

        if (hashmap_size(h) <= 0) {
                log_info("No items in catalog.");
                r = 0;
                goto finish;
        } else
                log_debug("Found %u items in catalog.", hashmap_size(h));

        strbuf_complete(sb);

        items = new(CatalogItem, hashmap_size(h));
        if (!items) {
                r = log_oom();
                goto finish;
        }

        n = 0;
        HASHMAP_FOREACH(i, h, j) {
                log_debug("Found " SD_ID128_FORMAT_STR ", language %s", SD_ID128_FORMAT_VAL(i->id), isempty(i->language) ? "C" : i->language);
                items[n++] = *i;
        }

        assert(n == hashmap_size(h));
        qsort(items, n, sizeof(CatalogItem), catalog_compare_func);

        r = mkdir_p(CATALOG_PATH, 0775);
        if (r < 0) {
                log_error("Recursive mkdir %s: %s", CATALOG_PATH, strerror(-r));
                goto finish;
        }

        r = fopen_temporary(CATALOG_DATABASE, &w, &p);
        if (r < 0) {
                log_error("Failed to open database for writing: %s: %s",
                          CATALOG_DATABASE, strerror(-r));
                goto finish;
        }

        zero(header);
        memcpy(header.signature, CATALOG_SIGNATURE, sizeof(header.signature));
        header.header_size = htole64(ALIGN_TO(sizeof(CatalogHeader), 8));
        header.catalog_item_size = htole64(sizeof(CatalogItem));
        header.n_items = htole64(hashmap_size(h));

        k = fwrite(&header, 1, sizeof(header), w);
        if (k != sizeof(header)) {
                log_error("%s: failed to write header.", p);
                goto finish;
        }

        k = fwrite(items, 1, n * sizeof(CatalogItem), w);
        if (k != n * sizeof(CatalogItem)) {
                log_error("%s: failed to write database.", p);
                goto finish;
        }

        k = fwrite(sb->buf, 1, sb->len, w);
        if (k != sb->len) {
                log_error("%s: failed to write strings.", p);
                goto finish;
        }

        fflush(w);

        if (ferror(w)) {
                log_error("%s: failed to write database.", p);
                goto finish;
        }

        fchmod(fileno(w), 0644);

        if (rename(p, CATALOG_DATABASE) < 0) {
                log_error("rename (%s -> %s) failed: %m", p, CATALOG_DATABASE);
                r = -errno;
                goto finish;
        }

        log_debug("%s: wrote %u items, with %zu bytes of strings, %zu total size.",
                 CATALOG_DATABASE, n, sb->len, ftell(w));

        free(p);
        p = NULL;

        r = 0;

finish:
        hashmap_free_free(h);

        if (sb)
                strbuf_cleanup(sb);

        if (p)
                unlink(p);

        return r;
}

static int open_mmap(int *_fd, struct stat *_st, void **_p) {
        const CatalogHeader *h;
        int fd;
        void *p;
        struct stat st;

        assert(_fd);
        assert(_st);
        assert(_p);

        fd = open("/var/lib/systemd/catalog/database", O_RDONLY|O_CLOEXEC);
        if (fd < 0)
                return -errno;

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

        if (st.st_size < (off_t) sizeof(CatalogHeader)) {
                close_nointr_nofail(fd);
                return -EINVAL;
        }

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

        h = p;
        if (memcmp(h->signature, CATALOG_SIGNATURE, sizeof(h->signature)) != 0 ||
            le64toh(h->header_size) < sizeof(CatalogHeader) ||
            le64toh(h->catalog_item_size) < sizeof(CatalogItem) ||
            h->incompatible_flags != 0 ||
            le64toh(h->n_items) <= 0 ||
            st.st_size < (off_t) (le64toh(h->header_size) + le64toh(h->catalog_item_size) * le64toh(h->n_items))) {
                close_nointr_nofail(fd);
                munmap(p, st.st_size);
                return -EBADMSG;
        }

        *_fd = fd;
        *_st = st;
        *_p = p;

        return 0;
}

static const char *find_id(void *p, sd_id128_t id) {
        CatalogItem key, *f = NULL;
        const CatalogHeader *h = p;
        const char *loc;

        zero(key);
        key.id = id;

        loc = setlocale(LC_MESSAGES, NULL);
        if (loc && loc[0] && !streq(loc, "C") && !streq(loc, "POSIX")) {
                strncpy(key.language, loc, sizeof(key.language));
                key.language[strcspn(key.language, ".@")] = 0;

                f = bsearch(&key, (const uint8_t*) p + le64toh(h->header_size), le64toh(h->n_items), le64toh(h->catalog_item_size), catalog_compare_func);
                if (!f) {
                        char *e;

                        e = strchr(key.language, '_');
                        if (e) {
                                *e = 0;
                                f = bsearch(&key, (const uint8_t*) p + le64toh(h->header_size), le64toh(h->n_items), le64toh(h->catalog_item_size), catalog_compare_func);
                        }
                }
        }

        if (!f) {
                zero(key.language);
                f = bsearch(&key, (const uint8_t*) p + le64toh(h->header_size), le64toh(h->n_items), le64toh(h->catalog_item_size), catalog_compare_func);
        }

        if (!f)
                return NULL;

        return (const char*) p +
                le64toh(h->header_size) +
                le64toh(h->n_items) * le64toh(h->catalog_item_size) +
                le64toh(f->offset);
}

int catalog_get(sd_id128_t id, char **_text) {
        _cleanup_close_ int fd = -1;
        void *p = NULL;
        struct stat st;
        char *text = NULL;
        int r;
        const char *s;

        assert(_text);

        r = open_mmap(&fd, &st, &p);
        if (r < 0)
                return r;

        s = find_id(p, id);
        if (!s) {
                r = -ENOENT;
                goto finish;
        }

        text = strdup(s);
        if (!text) {
                r = -ENOMEM;
                goto finish;
        }

        *_text = text;
        r = 0;

finish:
        if (p)
                munmap(p, st.st_size);

        return r;
}

static char *find_header(const char *s, const char *header) {

        for (;;) {
                const char *v, *e;

                v = startswith(s, header);
                if (v) {
                        v += strspn(v, WHITESPACE);
                        return strndup(v, strcspn(v, NEWLINE));
                }

                /* End of text */
                e = strchr(s, '\n');
                if (!e)
                        return NULL;

                /* End of header */
                if (e == s)
                        return NULL;

                s = e + 1;
        }
}

int catalog_list(FILE *f) {
        _cleanup_close_ int fd = -1;
        void *p = NULL;
        struct stat st;
        const CatalogHeader *h;
        const CatalogItem *items;
        int r;
        unsigned n;
        sd_id128_t last_id;
        bool last_id_set = false;

        r = open_mmap(&fd, &st, &p);
        if (r < 0)
                return r;

        h = p;
        items = (const CatalogItem*) ((const uint8_t*) p + le64toh(h->header_size));

        for (n = 0; n < le64toh(h->n_items); n++) {
                const char *s;
                _cleanup_free_ char *subject = NULL, *defined_by = NULL;

                if (last_id_set && sd_id128_equal(last_id, items[n].id))
                        continue;

                assert_se(s = find_id(p, items[n].id));

                subject = find_header(s, "Subject:");
                defined_by = find_header(s, "Defined-By:");

                fprintf(f, SD_ID128_FORMAT_STR " %s: %s\n", SD_ID128_FORMAT_VAL(items[n].id), strna(defined_by), strna(subject));

                last_id_set = true;
                last_id = items[n].id;
        }

        munmap(p, st.st_size);

        return 0;
}