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                 pid = fork();
  91                 if (pid < 0) {
  92                         r = log_error_errno(errno, "Failed to fork: %m");
  93                         goto finish;
  94                 }
  95
  96                 if (pid == 0) {
  97                         /* Child */
  98
  99                         (void) reset_all_signal_handlers();
 100                         (void) reset_signal_mask();
 101                         (void) prctl(PR_SET_PDEATHSIG, SIGTERM);
 102
 103                         execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount"));
 104
 105                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
 106                         _exit(EXIT_FAILURE);
 107                 }
 108
 109                 /* Parent */
 110
 111                 s = strdup(me->mnt_dir);
 112                 if (!s) {
 113                         r = log_oom();
 114                         goto finish;
 115                 }
 116
 117                 k = hashmap_put(pids, PID_TO_PTR(pid), s);
 118                 if (k < 0) {
 119                         free(s);
 120                         r = log_oom();
 121                         goto finish;
 122                 }
 123         }
 124
 125         r = 0;
 126         while (!hashmap_isempty(pids)) {
 127                 siginfo_t si = {};
 128                 char *s;
 129
 130                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
 131
 132                         if (errno == EINTR)
 133                                 continue;
 134
 135                         r = log_error_errno(errno, "waitid() failed: %m");
 136                         goto finish;
 137                 }
 138
 139                 s = hashmap_remove(pids, PID_TO_PTR(si.si_pid));
 140                 if (s) {
 141                         if (!is_clean_exit(si.si_code, si.si_status, EXIT_CLEAN_COMMAND, NULL)) {
 142                                 if (si.si_code == CLD_EXITED)
 143                                         log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 144                                 else
 145                                         log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 146
 147                                 r = -ENOEXEC;
 148                         }
 149
 150                         free(s);
 151                 }
 152         }
 153
 154 finish:
 155         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 156 }