src/remount-fs/remount-fs.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <mntent.h>
  24 #include <string.h>
  25 #include <sys/prctl.h>
  26 #include <sys/stat.h>
  27 #include <sys/wait.h>
  28 #include <unistd.h>
  29
  30 #include "exit-status.h"
  31 #include "log.h"
  32 #include "mount-setup.h"
  33 #include "mount-util.h"
  34 #include "path-util.h"
  35 #include "process-util.h"
  36 #include "signal-util.h"
  37 #include "strv.h"
  38 #include "util.h"
  39
  40 /* Goes through /etc/fstab and remounts all API file systems, applying
  41  * options that are in /etc/fstab that systemd might not have
  42  * respected */
  43
  44 int main(int argc, char *argv[]) {
  45         _cleanup_hashmap_free_free_ Hashmap *pids = NULL;
  46         _cleanup_endmntent_ FILE *f = NULL;
  47         struct mntent* me;
  48         int r;
  49
  50         if (argc > 1) {
  51                 log_error("This program takes no argument.");
  52                 return EXIT_FAILURE;
  53         }
  54
  55         log_set_target(LOG_TARGET_AUTO);
  56         log_parse_environment();
  57         log_open();
  58
  59         umask(0022);
  60
  61         f = setmntent("/etc/fstab", "r");
  62         if (!f) {
  63                 if (errno == ENOENT) {
  64                         r = 0;
  65                         goto finish;
  66                 }
  67
  68                 r = log_error_errno(errno, "Failed to open /etc/fstab: %m");
  69                 goto finish;
  70         }
  71
  72         pids = hashmap_new(NULL);
  73         if (!pids) {
  74                 r = log_oom();
  75                 goto finish;
  76         }
  77
  78         while ((me = getmntent(f))) {
  79                 pid_t pid;
  80                 int k;
  81                 char *s;
  82
  83                 /* Remount the root fs, /usr and all API VFS */
  84                 if (!mount_point_is_api(me->mnt_dir) &&
  85                     !path_equal(me->mnt_dir, "/") &&
  86                     !path_equal(me->mnt_dir, "/usr"))
  87                         continue;
  88
  89                 log_debug("Remounting %s", me->mnt_dir);
  90
  91                 pid = fork();
  92                 if (pid < 0) {
  93                         r = log_error_errno(errno, "Failed to fork: %m");
  94                         goto finish;
  95                 }
  96
  97                 if (pid == 0) {
  98                         /* Child */
  99
 100                         (void) reset_all_signal_handlers();
 101                         (void) reset_signal_mask();
 102                         (void) prctl(PR_SET_PDEATHSIG, SIGTERM);
 103
 104                         execv(MOUNT_PATH, STRV_MAKE(MOUNT_PATH, me->mnt_dir, "-o", "remount"));
 105
 106                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
 107                         _exit(EXIT_FAILURE);
 108                 }
 109
 110                 /* Parent */
 111
 112                 s = strdup(me->mnt_dir);
 113                 if (!s) {
 114                         r = log_oom();
 115                         goto finish;
 116                 }
 117
 118                 k = hashmap_put(pids, PID_TO_PTR(pid), s);
 119                 if (k < 0) {
 120                         free(s);
 121                         r = log_oom();
 122                         goto finish;
 123                 }
 124         }
 125
 126         r = 0;
 127         while (!hashmap_isempty(pids)) {
 128                 siginfo_t si = {};
 129                 char *s;
 130
 131                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
 132
 133                         if (errno == EINTR)
 134                                 continue;
 135
 136                         r = log_error_errno(errno, "waitid() failed: %m");
 137                         goto finish;
 138                 }
 139
 140                 s = hashmap_remove(pids, PID_TO_PTR(si.si_pid));
 141                 if (s) {
 142                         if (!is_clean_exit(si.si_code, si.si_status, NULL)) {
 143                                 if (si.si_code == CLD_EXITED)
 144                                         log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 145                                 else
 146                                         log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 147
 148                                 r = -ENOEXEC;
 149                         }
 150
 151                         free(s);
 152                 }
 153         }
 154
 155 finish:
 156         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 157 }