src/remount-fs/remount-fs.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 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 <errno.h>
  21 #include <mntent.h>
  22 #include <string.h>
  23 #include <sys/prctl.h>
  24 #include <sys/stat.h>
  25 #include <sys/wait.h>
  26 #include <unistd.h>
  27
  28 #include "exit-status.h"
  29 #include "log.h"
  30 #include "mount-setup.h"
  31 #include "mount-util.h"
  32 #include "path-util.h"
  33 #include "process-util.h"
  34 #include "signal-util.h"
  35 #include "strv.h"
  36 #include "util.h"
  37
  38 /* Goes through /etc/fstab and remounts all API file systems, applying
  39  * options that are in /etc/fstab that systemd might not have
  40  * respected */
  41
  42 int main(int argc, char *argv[]) {
  43         _cleanup_hashmap_free_free_ Hashmap *pids = NULL;
  44         _cleanup_endmntent_ FILE *f = NULL;
  45         struct mntent* me;
  46         int r;
  47
  48         if (argc > 1) {
  49                 log_error("This program takes no argument.");
  50                 return EXIT_FAILURE;
  51         }
  52
  53         log_set_target(LOG_TARGET_AUTO);
  54         log_parse_environment();
  55         log_open();
  56
  57         umask(0022);
  58
  59         f = setmntent("/etc/fstab", "r");
  60         if (!f) {
  61                 if (errno == ENOENT) {
  62                         r = 0;
  63                         goto finish;
  64                 }
  65
  66                 r = log_error_errno(errno, "Failed to open /etc/fstab: %m");
  67                 goto finish;
  68         }
  69
  70         pids = hashmap_new(NULL);
  71         if (!pids) {
  72                 r = log_oom();
  73                 goto finish;
  74         }
  75
  76         while ((me = getmntent(f))) {
  77                 pid_t pid;
  78                 int k;
  79                 char *s;
  80
  81                 /* Remount the root fs, /usr and all API VFS */
  82                 if (!mount_point_is_api(me->mnt_dir) &&
  83                     !path_equal(me->mnt_dir, "/") &&
  84                     !path_equal(me->mnt_dir, "/usr"))
  85                         continue;
  86
  87                 log_debug("Remounting %s", me->mnt_dir);
  88
  89                 pid = fork();
  90                 if (pid < 0) {
  91                         r = log_error_errno(errno, "Failed to fork: %m");
  92                         goto finish;
  93                 }
  94
  95                 if (pid == 0) {
  96                         /* Child */
  97
  98                         (void) reset_all_signal_handlers();
  99                         (void) reset_signal_mask();
 100                         (void) prctl(PR_SET_PDEATHSIG, SIGTERM);
 101
 102                         execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount"));
 103
 104                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
 105                         _exit(EXIT_FAILURE);
 106                 }
 107
 108                 /* Parent */
 109
 110                 s = strdup(me->mnt_dir);
 111                 if (!s) {
 112                         r = log_oom();
 113                         goto finish;
 114                 }
 115
 116                 k = hashmap_put(pids, PID_TO_PTR(pid), s);
 117                 if (k < 0) {
 118                         free(s);
 119                         r = log_oom();
 120                         goto finish;
 121                 }
 122         }
 123
 124         r = 0;
 125         while (!hashmap_isempty(pids)) {
 126                 siginfo_t si = {};
 127                 char *s;
 128
 129                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
 130
 131                         if (errno == EINTR)
 132                                 continue;
 133
 134                         r = log_error_errno(errno, "waitid() failed: %m");
 135                         goto finish;
 136                 }
 137
 138                 s = hashmap_remove(pids, PID_TO_PTR(si.si_pid));
 139                 if (s) {
 140                         if (!is_clean_exit(si.si_code, si.si_status, EXIT_CLEAN_COMMAND, NULL)) {
 141                                 if (si.si_code == CLD_EXITED)
 142                                         log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 143                                 else
 144                                         log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 145
 146                                 r = -ENOEXEC;
 147                         }
 148
 149                         free(s);
 150                 }
 151         }
 152
 153 finish:
 154         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 155 }