src/update-done/update-done.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2014 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include "fd-util.h"
  21 #include "io-util.h"
  22 #include "selinux-util.h"
  23 #include "util.h"
  24
  25 #define MESSAGE                                                         \
  26         "This file was created by systemd-update-done. Its only \n"     \
  27         "purpose is to hold a timestamp of the time this directory\n"   \
  28         "was updated. See systemd-update-done.service(8).\n"
  29
  30 static int apply_timestamp(const char *path, struct timespec *ts) {
  31         struct timespec twice[2] = {
  32                 *ts,
  33                 *ts
  34         };
  35         struct stat st;
  36
  37         assert(path);
  38         assert(ts);
  39
  40         if (stat(path, &st) >= 0) {
  41                 /* Is the timestamp file already newer than the OS? If
  42                  * so, there's nothing to do. We ignore the nanosecond
  43                  * component of the timestamp, since some file systems
  44                  * do not support any better accuracy than 1s and we
  45                  * have no way to identify the accuracy
  46                  * available. Most notably ext4 on small disks (where
  47                  * 128 byte inodes are used) does not support better
  48                  * accuracy than 1s. */
  49                 if (st.st_mtim.tv_sec > ts->tv_sec)
  50                         return 0;
  51
  52                 /* It is older? Then let's update it */
  53                 if (utimensat(AT_FDCWD, path, twice, AT_SYMLINK_NOFOLLOW) < 0) {
  54
  55                         if (errno == EROFS)
  56                                 return log_debug("Can't update timestamp file %s, file system is read-only.", path);
  57
  58                         return log_error_errno(errno, "Failed to update timestamp on %s: %m", path);
  59                 }
  60
  61         } else if (errno == ENOENT) {
  62                 _cleanup_close_ int fd = -1;
  63                 int r;
  64
  65                 /* The timestamp file doesn't exist yet? Then let's create it. */
  66
  67                 r = mac_selinux_create_file_prepare(path, S_IFREG);
  68                 if (r < 0)
  69                         return log_error_errno(r, "Failed to set SELinux context for %s: %m", path);
  70
  71                 fd = open(path, O_CREAT|O_EXCL|O_WRONLY|O_TRUNC|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644);
  72                 mac_selinux_create_file_clear();
  73
  74                 if (fd < 0) {
  75                         if (errno == EROFS)
  76                                 return log_debug("Can't create timestamp file %s, file system is read-only.", path);
  77
  78                         return log_error_errno(errno, "Failed to create timestamp file %s: %m", path);
  79                 }
  80
  81                 (void) loop_write(fd, MESSAGE, strlen(MESSAGE), false);
  82
  83                 if (futimens(fd, twice) < 0)
  84                         return log_error_errno(errno, "Failed to update timestamp on %s: %m", path);
  85         } else
  86                 log_error_errno(errno, "Failed to stat() timestamp file %s: %m", path);
  87
  88         return 0;
  89 }
  90
  91 int main(int argc, char *argv[]) {
  92         struct stat st;
  93         int r, q = 0;
  94
  95         log_set_target(LOG_TARGET_AUTO);
  96         log_parse_environment();
  97         log_open();
  98
  99         if (stat("/usr", &st) < 0) {
 100                 log_error_errno(errno, "Failed to stat /usr: %m");
 101                 return EXIT_FAILURE;
 102         }
 103
 104         r = mac_selinux_init(NULL);
 105         if (r < 0) {
 106                 log_error_errno(r, "SELinux setup failed: %m");
 107                 goto finish;
 108         }
 109
 110         r = apply_timestamp("/etc/.updated", &st.st_mtim);
 111         q = apply_timestamp("/var/.updated", &st.st_mtim);
 112
 113 finish:
 114         return r < 0 || q < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 115 }