src/hibernate-resume/hibernate-resume.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2014 Ivan Shapovalov
   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 <stdio.h>
  22 #include <sys/stat.h>
  23
  24 #include "alloc-util.h"
  25 #include "fileio.h"
  26 #include "log.h"
  27 #include "util.h"
  28
  29 int main(int argc, char *argv[]) {
  30         struct stat st;
  31         const char *device;
  32         _cleanup_free_ char *major_minor = NULL;
  33         int r;
  34
  35         if (argc != 2) {
  36                 log_error("This program expects one argument.");
  37                 return EXIT_FAILURE;
  38         }
  39
  40         log_set_target(LOG_TARGET_AUTO);
  41         log_parse_environment();
  42         log_open();
  43
  44         umask(0022);
  45
  46         /* Refuse to run unless we are in an initrd() */
  47         if (!in_initrd())
  48                 return EXIT_SUCCESS;
  49
  50         device = argv[1];
  51
  52         if (stat(device, &st) < 0) {
  53                 log_error_errno(errno, "Failed to stat '%s': %m", device);
  54                 return EXIT_FAILURE;
  55         }
  56
  57         if (!S_ISBLK(st.st_mode)) {
  58                 log_error("Resume device '%s' is not a block device.", device);
  59                 return EXIT_FAILURE;
  60         }
  61
  62         if (asprintf(&major_minor, "%d:%d", major(st.st_rdev), minor(st.st_rdev)) < 0) {
  63                 log_oom();
  64                 return EXIT_FAILURE;
  65         }
  66
  67         r = write_string_file("/sys/power/resume", major_minor, WRITE_STRING_FILE_CREATE);
  68         if (r < 0) {
  69                 log_error_errno(r, "Failed to write '%s' to /sys/power/resume: %m", major_minor);
  70                 return EXIT_FAILURE;
  71         }
  72
  73         /*
  74          * The write above shall not return.
  75          *
  76          * However, failed resume is a normal condition (may mean that there is
  77          * no hibernation image).
  78          */
  79
  80         log_info("Could not resume from '%s' (%s).", device, major_minor);
  81         return EXIT_SUCCESS;
  82 }