src/remount-fs/remount-fs.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <mntent.h>
   5 #include <string.h>
   6 #include <sys/prctl.h>
   7 #include <sys/stat.h>
   8 #include <sys/wait.h>
   9 #include <unistd.h>
  10
  11 #include "exit-status.h"
  12 #include "log.h"
  13 #include "main-func.h"
  14 #include "mount-setup.h"
  15 #include "mount-util.h"
  16 #include "path-util.h"
  17 #include "process-util.h"
  18 #include "signal-util.h"
  19 #include "strv.h"
  20 #include "util.h"
  21
  22 /* Goes through /etc/fstab and remounts all API file systems, applying
  23  * options that are in /etc/fstab that systemd might not have
  24  * respected */
  25
  26 static int run(int argc, char *argv[]) {
  27         _cleanup_hashmap_free_free_ Hashmap *pids = NULL;
  28         _cleanup_endmntent_ FILE *f = NULL;
  29         struct mntent* me;
  30         int r;
  31
  32         log_setup_service();
  33
  34         if (argc > 1)
  35                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
  36                                        "This program takes no arguments.");
  37
  38         umask(0022);
  39
  40         f = setmntent("/etc/fstab", "re");
  41         if (!f) {
  42                 if (errno == ENOENT)
  43                         return 0;
  44
  45                 return log_error_errno(errno, "Failed to open /etc/fstab: %m");
  46         }
  47
  48         pids = hashmap_new(NULL);
  49         if (!pids)
  50                 return log_oom();
  51
  52         while ((me = getmntent(f))) {
  53                 _cleanup_free_ char *s = NULL;
  54                 pid_t pid;
  55                 int k;
  56
  57                 /* Remount the root fs, /usr and all API VFS */
  58                 if (!mount_point_is_api(me->mnt_dir) &&
  59                     !path_equal(me->mnt_dir, "/") &&
  60                     !path_equal(me->mnt_dir, "/usr"))
  61                         continue;
  62
  63                 log_debug("Remounting %s", me->mnt_dir);
  64
  65                 r = safe_fork("(remount)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG, &pid);
  66                 if (r < 0)
  67                         return r;
  68                 if (r == 0) {
  69                         /* Child */
  70
  71                         execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount"));
  72
  73                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
  74                         _exit(EXIT_FAILURE);
  75                 }
  76
  77                 /* Parent */
  78
  79                 s = strdup(me->mnt_dir);
  80                 if (!s)
  81                         return log_oom();
  82
  83                 k = hashmap_put(pids, PID_TO_PTR(pid), s);
  84                 if (k < 0)
  85                         return log_oom();
  86                 TAKE_PTR(s);
  87         }
  88
  89         r = 0;
  90         while (!hashmap_isempty(pids)) {
  91                 siginfo_t si = {};
  92                 _cleanup_free_ char *s = NULL;
  93
  94                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
  95                         if (errno == EINTR)
  96                                 continue;
  97
  98                         return log_error_errno(errno, "waitid() failed: %m");
  99                 }
 100
 101                 s = hashmap_remove(pids, PID_TO_PTR(si.si_pid));
 102                 if (s &&
 103                     !is_clean_exit(si.si_code, si.si_status, EXIT_CLEAN_COMMAND, NULL)) {
 104                         if (si.si_code == CLD_EXITED)
 105                                 log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 106                         else
 107                                 log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 108
 109                         r = -ENOEXEC;
 110                 }
 111         }
 112
 113         return r;
 114 }
 115
 116 DEFINE_MAIN_FUNCTION(run);