src/remount-fs/remount-fs.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <errno.h>
  22 #include <mntent.h>
  23 #include <string.h>
  24 #include <sys/prctl.h>
  25 #include <sys/stat.h>
  26 #include <sys/wait.h>
  27 #include <unistd.h>
  28
  29 #include "exit-status.h"
  30 #include "log.h"
  31 #include "mount-setup.h"
  32 #include "mount-util.h"
  33 #include "path-util.h"
  34 #include "process-util.h"
  35 #include "signal-util.h"
  36 #include "strv.h"
  37 #include "util.h"
  38
  39 /* Goes through /etc/fstab and remounts all API file systems, applying
  40  * options that are in /etc/fstab that systemd might not have
  41  * respected */
  42
  43 int main(int argc, char *argv[]) {
  44         _cleanup_hashmap_free_free_ Hashmap *pids = NULL;
  45         _cleanup_endmntent_ FILE *f = NULL;
  46         struct mntent* me;
  47         int r;
  48
  49         if (argc > 1) {
  50                 log_error("This program takes no argument.");
  51                 return EXIT_FAILURE;
  52         }
  53
  54         log_set_target(LOG_TARGET_AUTO);
  55         log_parse_environment();
  56         log_open();
  57
  58         umask(0022);
  59
  60         f = setmntent("/etc/fstab", "re");
  61         if (!f) {
  62                 if (errno == ENOENT) {
  63                         r = 0;
  64                         goto finish;
  65                 }
  66
  67                 r = log_error_errno(errno, "Failed to open /etc/fstab: %m");
  68                 goto finish;
  69         }
  70
  71         pids = hashmap_new(NULL);
  72         if (!pids) {
  73                 r = log_oom();
  74                 goto finish;
  75         }
  76
  77         while ((me = getmntent(f))) {
  78                 pid_t pid;
  79                 int k;
  80                 char *s;
  81
  82                 /* Remount the root fs, /usr and all API VFS */
  83                 if (!mount_point_is_api(me->mnt_dir) &&
  84                     !path_equal(me->mnt_dir, "/") &&
  85                     !path_equal(me->mnt_dir, "/usr"))
  86                         continue;
  87
  88                 log_debug("Remounting %s", me->mnt_dir);
  89
  90                 r = safe_fork("(remount)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
  91                 if (r < 0)
  92                         goto finish;
  93                 if (r == 0) {
  94                         /* Child */
  95
  96                         execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount"));
  97
  98                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
  99                         _exit(EXIT_FAILURE);
 100                 }
 101
 102                 /* Parent */
 103
 104                 s = strdup(me->mnt_dir);
 105                 if (!s) {
 106                         r = log_oom();
 107                         goto finish;
 108                 }
 109
 110                 k = hashmap_put(pids, PID_TO_PTR(pid), s);
 111                 if (k < 0) {
 112                         free(s);
 113                         r = log_oom();
 114                         goto finish;
 115                 }
 116         }
 117
 118         r = 0;
 119         while (!hashmap_isempty(pids)) {
 120                 siginfo_t si = {};
 121                 char *s;
 122
 123                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
 124
 125                         if (errno == EINTR)
 126                                 continue;
 127
 128                         r = log_error_errno(errno, "waitid() failed: %m");
 129                         goto finish;
 130                 }
 131
 132                 s = hashmap_remove(pids, PID_TO_PTR(si.si_pid));
 133                 if (s) {
 134                         if (!is_clean_exit(si.si_code, si.si_status, EXIT_CLEAN_COMMAND, NULL)) {
 135                                 if (si.si_code == CLD_EXITED)
 136                                         log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 137                                 else
 138                                         log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 139
 140                                 r = -ENOEXEC;
 141                         }
 142
 143                         free(s);
 144                 }
 145         }
 146
 147 finish:
 148         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 149 }