src/lib-storage/mailbox-uidvalidity.c

	mailbox-uidvalidity.c revision 0e881a691e6d2d2836d923ef3e92b14aeda60f0d
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen/* Copyright (c) 2008 Dovecot authors, see the included COPYING file */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "lib.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "ioloop.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "str.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "read-full.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "write-full.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include "mailbox-uidvalidity.h"
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include <stdio.h>
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include <stdlib.h>
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include <unistd.h>
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include <dirent.h>
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#include <fcntl.h>
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen#define RETRY_COUNT 10
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainenstatic uint32_t mailbox_uidvalidity_next_fallback(void)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen{
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    static uint32_t uid_validity = 0;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    /* we failed to use the uidvalidity file. don't fail the mailbox
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen       creation because of it though, most of the time it's safe enough
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen       to use the current time as the uidvalidity value. */
0e881a691e6d2d2836d923ef3e92b14aeda60f0dTimo Sirainen    if (uid_validity < (uint32_t)ioloop_time)
0e881a691e6d2d2836d923ef3e92b14aeda60f0dTimo Sirainen        uid_validity = (uint32_t)ioloop_time;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    else
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        uid_validity++;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    return uid_validity;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen}
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainenstatic void mailbox_uidvalidity_write(const char *path, uint32_t uid_validity)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen{
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    char buf[8+1];
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    int fd;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    fd = open(path, O_RDWR | O_CREAT, 0666);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (fd == -1) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("open(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    i_snprintf(buf, sizeof(buf), "%08x", uid_validity);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (pwrite_full(fd, buf, strlen(buf), 0) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("write(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (close(fd) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("close(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen}
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainenstatic int mailbox_uidvalidity_rename(const char *path, uint32_t *uid_validity)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen{
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    string_t *src, *dest;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    unsigned int i, prefix_len;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    int ret;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    src = t_str_new(256);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    str_append(src, path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    dest = t_str_new(256);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    str_append(dest, path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    prefix_len = str_len(src);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    for (i = 0; i < RETRY_COUNT; i++) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        str_printfa(src, ".%08x", *uid_validity);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        *uid_validity += 1;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        str_printfa(dest, ".%08x", *uid_validity);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        if ((ret = rename(str_c(src), str_c(dest))) == 0 ||
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            errno != ENOENT)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            break;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        /* possibly a race condition. try the next value. */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        str_truncate(src, prefix_len);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        str_truncate(dest, prefix_len);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (ret < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("rename(%s, %s) failed: %m", str_c(src), str_c(dest));
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    return ret;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen}
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainenstatic uint32_t mailbox_uidvalidity_next_rescan(const char *path)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen{
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    DIR *d;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    struct dirent *dp;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    const char *fname, *dir, *prefix, *tmp;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    char *endp;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    unsigned int i, prefix_len;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    uint32_t cur_value, min_value, max_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    int fd;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    fname = strrchr(path, '/');
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (fname == NULL) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        dir = ".";
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        fname = path;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    } else {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        dir = t_strdup_until(path, fname);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        fname++;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    d = opendir(dir);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (d == NULL) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("opendir(%s) failed: %m", dir);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_fallback();
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    prefix = t_strconcat(fname, ".", NULL);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    prefix_len = strlen(prefix);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    /* just in case there happens to be multiple matching uidvalidity
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen       files, track the min/max values. use the max value and delete the
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen       min value file. */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    max_value = 0; min_value = (uint32_t)-1;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    while ((dp = readdir(d)) != NULL) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        if (strncmp(dp->d_name, prefix, prefix_len) == 0) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            cur_value = strtoul(dp->d_name + prefix_len, &endp, 16);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            if (*endp == '\0') {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen                if (min_value > cur_value)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen                    min_value = cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen                if (max_value < cur_value)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen                    max_value = cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (closedir(d) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("closedir(%s) failed: %m", dir);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (max_value == 0) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        /* no uidvalidity files. create one. */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        for (i = 0; i < RETRY_COUNT; i++) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            cur_value = mailbox_uidvalidity_next_fallback();
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            tmp = t_strdup_printf("%s.%08x", path, cur_value);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            fd = open(tmp, O_RDWR | O_CREAT | O_EXCL, 0666);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            if (fd != -1 || errno != EEXIST)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen                break;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            /* already exists. although it's quite unlikely we'll
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen               hit this race condition. more likely we'll create
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen               a duplicate file.. */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        if (fd == -1) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            i_error("creat(%s) failed: %m", tmp);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            return cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        (void)close(fd);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        mailbox_uidvalidity_write(path, cur_value);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (min_value != max_value) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        /* duplicate uidvalidity files, delete the oldest */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        tmp = t_strdup_printf("%s.%08x", path, min_value);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        if (unlink(tmp) < 0 && errno != ENOENT)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            i_error("unlink(%s) failed: %m", tmp);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    cur_value = max_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (mailbox_uidvalidity_rename(path, &cur_value) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_fallback();
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    mailbox_uidvalidity_write(path, cur_value);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    return cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen}
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainenuint32_t mailbox_uidvalidity_next(const char *path)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen{
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    char buf[8+1], *endp;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    uint32_t cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    int fd, ret;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    fd = open(path, O_RDWR);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (fd == -1) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        if (errno != ENOENT)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen            i_error("open(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_rescan(path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    ret = read_full(fd, buf, sizeof(buf)-1);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (ret < 0) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("read(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        (void)close(fd);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_rescan(path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    buf[sizeof(buf)-1] = 0;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    cur_value = strtoul(buf, &endp, 16);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (ret == 0 || endp != buf+sizeof(buf)-1) {
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        /* broken value */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        (void)close(fd);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_rescan(path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    }
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    /* we now have the current uidvalidity value that's hopefully correct */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (mailbox_uidvalidity_rename(path, &cur_value) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        return mailbox_uidvalidity_next_rescan(path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    /* fast path succeeded. write the current value to the main
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen       uidvalidity file. */
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    i_snprintf(buf, sizeof(buf), "%08x", cur_value);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (pwrite_full(fd, buf, strlen(buf), 0) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("write(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    if (close(fd) < 0)
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen        i_error("close(%s) failed: %m", path);
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen    return cur_value;
300baf826ba39003b861e7716c35bae372e6f23eTimo Sirainen}