src/lib-index/mail-index-write.c

	mail-index-write.c revision aee5e9a405121be95b8e34f632d2e12797f92cc4
/* Copyright (C) 2003-2007 Timo Sirainen */

#include "lib.h"
#include "write-full.h"
#include "mail-index-private.h"
#include "mail-transaction-log-private.h"

#include <stdio.h>

static int mail_index_recreate(struct mail_index *index)
{
    struct mail_index_map *map = index->map;
    unsigned int base_size;
    const char *path;
    int ret, fd;

    i_assert(!MAIL_INDEX_IS_IN_MEMORY(index));

    fd = mail_index_create_tmp_file(index, &path);
    if (fd == -1)
        return -1;

    /* write base header */
    base_size = I_MIN(map->hdr.base_header_size, sizeof(map->hdr));
    ret = write_full(fd, &map->hdr, base_size);
    if (ret == 0) {
        /* write extended headers */
        ret = write_full(fd, CONST_PTR_OFFSET(map->hdr_base, base_size),
                 map->hdr.header_size - base_size);
    }
    if (ret == 0) {
        ret = write_full(fd, map->records, map->records_count *
                 map->hdr.record_size);
    }
    if (ret < 0)
        mail_index_file_set_syscall_error(index, path, "write_full()");

    if (ret == 0 && !index->fsync_disable && fsync(fd) < 0) {
        mail_index_file_set_syscall_error(index, path, "fsync()");
        ret = -1;
    }

    if (close(fd) < 0) {
        mail_index_file_set_syscall_error(index, path, "close()");
        ret = -1;
    }

    if (ret == 0 && rename(path, index->filepath) < 0) {
        mail_index_set_error(index, "rename(%s, %s) failed: %m",
                     path, index->filepath);
        ret = -1;
    }

    if (ret < 0) {
        if (unlink(path) < 0) {
            mail_index_set_error(index, "unlink(%s) failed: %m",
                         path);
        }
    }
    return ret;
}

static int mail_index_write_map_over(struct mail_index *index)
{
    struct mail_index_map *map = index->map;
    unsigned int base_size;

    if (MAIL_INDEX_IS_IN_MEMORY(index))
        return 0;

    /* write records. */
    if (map->write_seq_first != 0) {
        size_t rec_offset =
            (map->write_seq_first-1) * map->hdr.record_size;

        if (pwrite_full(index->fd,
                CONST_PTR_OFFSET(map->records, rec_offset),
                (map->write_seq_last -
                 map->write_seq_first + 1) *
                map->hdr.record_size,
                map->hdr.header_size + rec_offset) < 0)
            return -1;
    }

    /* write base header. it has changed practically always, so
       map->write_base_header might not be TRUE here in all situations.
       It's used only to figure out if we want to write the map at all. */
    base_size = I_MIN(map->hdr.base_header_size, sizeof(map->hdr));
    if (pwrite_full(index->fd, &map->hdr, base_size, 0) < 0)
        return -1;

    /* write extended headers */
    if (map->write_ext_header) {
        base_size = map->hdr.base_header_size;
        if (pwrite_full(index->fd,
                CONST_PTR_OFFSET(map->hdr_base, base_size),
                map->hdr.header_size - base_size,
                base_size) < 0)
            return -1;
    }
    return 0;
}

#define mail_index_map_has_changed(map) \
    ((map)->write_base_header || (map)->write_ext_header || \
     (map)->write_seq_first != 0)

void mail_index_write(struct mail_index *index, bool want_rotate)
{
    struct mail_index_map *map = index->map;
    const struct mail_index_header *hdr = &map->hdr;
    unsigned int lock_id;

    if (!mail_index_map_has_changed(map))
        return;

    if (hdr->base_header_size < sizeof(*hdr)) {
        /* header size growed. we can't update this file anymore. */
        map->write_atomic = TRUE;
    }
    if (index->fd == -1) {
        /* index file doesn't exist, it's corrupted or we haven't
           opened it for some reason */
        map->write_atomic = TRUE;
    }
    if (!map->write_atomic) {
        if (mail_index_try_lock_exclusive(index, &lock_id) <= 0) {
            /* locking failed, rewrite */
            map->write_atomic = TRUE;
        }
    }

    if (map->write_atomic) {
        if (!MAIL_INDEX_IS_IN_MEMORY(index)) {
            if (mail_index_recreate(index) < 0) {
                mail_index_move_to_memory(index);
                return;
            }
        }
    } else {
        if (mail_index_write_map_over(index) < 0) {
            mail_index_set_error(index,
                "pwrite_full(%s) failed: %m", index->filepath);
            mail_index_set_inconsistent(index);
        }
        mail_index_unlock(index, lock_id);
    }

    index->last_read_log_file_tail_offset = hdr->log_file_tail_offset;

    map->write_atomic = FALSE;
    map->write_seq_first = map->write_seq_last = 0;
    map->write_base_header = FALSE;
    map->write_ext_header = FALSE;

    if (want_rotate &&
        hdr->log_file_seq == index->log->head->hdr.file_seq &&
        hdr->log_file_tail_offset == hdr->log_file_head_offset)
        (void)mail_transaction_log_rotate(index->log);
}