index/maildir/maildir-util.c

	maildir-util.c revision b142deb9a831c89b1bb9129ada655f3e56b9d4cc
/* Copyright (C) 2004 Timo Sirainen */

#include "lib.h"
#include "hostpid.h"
#include "ioloop.h"
#include "str.h"
#include "maildir-storage.h"
#include "maildir-uidlist.h"
#include "maildir-keywords.h"

#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>

static int maildir_file_do_try(struct maildir_mailbox *mbox, uint32_t uid,
                   maildir_file_do_func *func, void *context)
{
    const char *fname, *path;
        enum maildir_uidlist_rec_flag flags;
    int ret;

    fname = maildir_uidlist_lookup(mbox->uidlist, uid, &flags);
    if (fname == NULL)
        return -2; /* expunged */

    t_push();
    if ((flags & MAILDIR_UIDLIST_REC_FLAG_NEW_DIR) != 0) {
        /* probably in new/ dir */
        path = t_strconcat(mbox->path, "/new/", fname, NULL);
        ret = func(mbox, path, context);
        if (ret != 0) {
            t_pop();
            return ret;
        }
    }

    path = t_strconcat(mbox->path, "/cur/", fname, NULL);
    ret = func(mbox, path, context);
    t_pop();
    return ret;
}

int maildir_file_do(struct maildir_mailbox *mbox, uint32_t uid,
            maildir_file_do_func *func, void *context)
{
    int i, ret;

    ret = maildir_file_do_try(mbox, uid, func, context);
    for (i = 0; i < 10 && ret == 0; i++) {
        /* file is either renamed or deleted. sync the maildir and
           see which one. if file appears to be renamed constantly,
           don't try to open it more than 10 times. */
        if (maildir_storage_sync_force(mbox) < 0)
            return -1;

        ret = maildir_file_do_try(mbox, uid, func, context);
    }

    if (i == 10) {
        ret = -1;
        mail_storage_set_critical(STORAGE(mbox->storage),
            "maildir_file_do(%s) racing", mbox->path);
    }

    return ret == -2 ? 0 : ret;
}

const char *maildir_generate_tmp_filename(const struct timeval *tv)
{
    static unsigned int create_count = 0;
    static time_t first_stamp = 0;

    if (first_stamp == 0 || first_stamp == ioloop_time) {
        /* it's possible that within last second another process had
           the same PID as us. Use usecs to make sure we don't create
           duplicate base name. */
        first_stamp = ioloop_time;
        return t_strdup_printf("%s.P%sQ%uM%s.%s",
                       dec2str(tv->tv_sec), my_pid,
                       create_count++,
                       dec2str(tv->tv_usec), my_hostname);
    } else {
        /* Don't bother with usecs. Saves a bit space :) */
        return t_strdup_printf("%s.P%sQ%u.%s",
                       dec2str(tv->tv_sec), my_pid,
                       create_count++, my_hostname);
    }
}

int maildir_create_tmp(struct maildir_mailbox *mbox, const char *dir,
               mode_t mode, const char **fname_r)
{
    const char *path, *tmp_fname;
    struct stat st;
    struct timeval *tv, tv_now;
    pool_t pool;
    int fd;

    tv = &ioloop_timeval;
    pool = pool_alloconly_create("maildir_tmp", 4096);
    for (;;) {
        p_clear(pool);
        tmp_fname = maildir_generate_tmp_filename(tv);

        path = p_strconcat(pool, dir, "/", tmp_fname, NULL);
        if (stat(path, &st) < 0 && errno == ENOENT) {
            /* doesn't exist */
            mode_t old_mask = umask(0);
            fd = open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
            umask(old_mask);
            if (fd != -1 || errno != EEXIST)
                break;
        }

        /* wait and try again - very unlikely */
        sleep(2);
        tv = &tv_now;
        if (gettimeofday(&tv_now, NULL) < 0)
            i_fatal("gettimeofday(): %m");
    }

    *fname_r = t_strdup(path);
    if (fd == -1) {
        if (ENOSPACE(errno)) {
            mail_storage_set_error(STORAGE(mbox->storage),
                           "Not enough disk space");
        } else {
            mail_storage_set_critical(STORAGE(mbox->storage),
                          "open(%s) failed: %m", path);
        }
    }

    pool_unref(pool);
    return fd;
}

bool maildir_filename_get_size(const char *fname, char type, uoff_t *size_r)
{
    uoff_t size = 0;

    for (; *fname != '\0'; fname++) {
        i_assert(*fname != '/');
        if (*fname == ',' && fname[1] == type && fname[2] == '=') {
            fname += 3;
            break;
        }
    }

    if (*fname == '\0')
        return FALSE;

    while (*fname >= '0' && *fname <= '9') {
        size = size * 10 + (*fname - '0');
        fname++;
    }

    if (*fname != MAILDIR_INFO_SEP &&
        *fname != MAILDIR_EXTRA_SEP &&
        *fname != '\0')
        return FALSE;

    *size_r = size;
    return TRUE;
}

/* a char* hash function from ASU -- from glib */
unsigned int maildir_hash(const void *p)
{
        const unsigned char *s = p;
    unsigned int g, h = 0;

    while (*s != MAILDIR_INFO_SEP && *s != '\0') {
        i_assert(*s != '/');
        h = (h << 4) + *s;
        if ((g = h & 0xf0000000UL)) {
            h = h ^ (g >> 24);
            h = h ^ g;
        }

        s++;
    }

    return h;
}

int maildir_cmp(const void *p1, const void *p2)
{
    const char *s1 = p1, *s2 = p2;

    while (*s1 == *s2 && *s1 != MAILDIR_INFO_SEP && *s1 != '\0') {
        i_assert(*s1 != '/');
        s1++; s2++;
    }
    if ((*s1 == '\0' || *s1 == MAILDIR_INFO_SEP) &&
        (*s2 == '\0' || *s2 == MAILDIR_INFO_SEP))
        return 0;
    return *s1 - *s2;
}