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 <unistd.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/stat.h>
  26 #include <sys/wait.h>
  27 #include <mntent.h>
  28
  29 #include "log.h"
  30 #include "util.h"
  31 #include "path-util.h"
  32 #include "signal-util.h"
  33 #include "mount-setup.h"
  34 #include "exit-status.h"
  35
  36 /* Goes through /etc/fstab and remounts all API file systems, applying
  37  * options that are in /etc/fstab that systemd might not have
  38  * respected */
  39
  40 int main(int argc, char *argv[]) {
  41         int ret = EXIT_FAILURE;
  42         _cleanup_endmntent_ FILE *f = NULL;
  43         struct mntent* me;
  44         Hashmap *pids = NULL;
  45
  46         if (argc > 1) {
  47                 log_error("This program takes no argument.");
  48                 return EXIT_FAILURE;
  49         }
  50
  51         log_set_target(LOG_TARGET_AUTO);
  52         log_parse_environment();
  53         log_open();
  54
  55         umask(0022);
  56
  57         f = setmntent("/etc/fstab", "r");
  58         if (!f) {
  59                 if (errno == ENOENT)
  60                         return EXIT_SUCCESS;
  61
  62                 log_error_errno(errno, "Failed to open /etc/fstab: %m");
  63                 return EXIT_FAILURE;
  64         }
  65
  66         pids = hashmap_new(NULL);
  67         if (!pids) {
  68                 log_error("Failed to allocate set");
  69                 goto finish;
  70         }
  71
  72         ret = EXIT_SUCCESS;
  73
  74         while ((me = getmntent(f))) {
  75                 pid_t pid;
  76                 int k;
  77                 char *s;
  78
  79                 /* Remount the root fs, /usr and all API VFS */
  80                 if (!mount_point_is_api(me->mnt_dir) &&
  81                     !path_equal(me->mnt_dir, "/") &&
  82                     !path_equal(me->mnt_dir, "/usr"))
  83                         continue;
  84
  85                 log_debug("Remounting %s", me->mnt_dir);
  86
  87                 pid = fork();
  88                 if (pid < 0) {
  89                         log_error_errno(errno, "Failed to fork: %m");
  90                         ret = EXIT_FAILURE;
  91                         continue;
  92                 }
  93
  94                 if (pid == 0) {
  95                         const char *arguments[5];
  96                         /* Child */
  97
  98                         (void) reset_all_signal_handlers();
  99                         (void) reset_signal_mask();
 100
 101                         arguments[0] = MOUNT_PATH;
 102                         arguments[1] = me->mnt_dir;
 103                         arguments[2] = "-o";
 104                         arguments[3] = "remount";
 105                         arguments[4] = NULL;
 106
 107                         execv(MOUNT_PATH, (char **) arguments);
 108
 109                         log_error_errno(errno, "Failed to execute " MOUNT_PATH ": %m");
 110                         _exit(EXIT_FAILURE);
 111                 }
 112
 113                 /* Parent */
 114
 115                 s = strdup(me->mnt_dir);
 116                 if (!s) {
 117                         log_oom();
 118                         ret = EXIT_FAILURE;
 119                         continue;
 120                 }
 121
 122
 123                 k = hashmap_put(pids, UINT_TO_PTR(pid), s);
 124                 if (k < 0) {
 125                         log_error_errno(k, "Failed to add PID to set: %m");
 126                         ret = EXIT_FAILURE;
 127                         continue;
 128                 }
 129         }
 130
 131         while (!hashmap_isempty(pids)) {
 132                 siginfo_t si = {};
 133                 char *s;
 134
 135                 if (waitid(P_ALL, 0, &si, WEXITED) < 0) {
 136
 137                         if (errno == EINTR)
 138                                 continue;
 139
 140                         log_error_errno(errno, "waitid() failed: %m");
 141                         ret = EXIT_FAILURE;
 142                         break;
 143                 }
 144
 145                 s = hashmap_remove(pids, UINT_TO_PTR(si.si_pid));
 146                 if (s) {
 147                         if (!is_clean_exit(si.si_code, si.si_status, NULL)) {
 148                                 if (si.si_code == CLD_EXITED)
 149                                         log_error(MOUNT_PATH " for %s exited with exit status %i.", s, si.si_status);
 150                                 else
 151                                         log_error(MOUNT_PATH " for %s terminated by signal %s.", s, signal_to_string(si.si_status));
 152
 153                                 ret = EXIT_FAILURE;
 154                         }
 155
 156                         free(s);
 157                 }
 158         }
 159
 160 finish:
 161
 162         if (pids)
 163                 hashmap_free_free(pids);
 164
 165         return ret;
 166 }