src/hibernate-resume/hibernate-resume.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <stdio.h>
   5 #include <sys/stat.h>
   6
   7 #include "alloc-util.h"
   8 #include "devnum-util.h"
   9 #include "fileio.h"
  10 #include "log.h"
  11 #include "util.h"
  12
  13 int main(int argc, char *argv[]) {
  14         struct stat st;
  15         const char *device;
  16         int r;
  17
  18         if (argc != 2) {
  19                 log_error("This program expects one argument.");
  20                 return EXIT_FAILURE;
  21         }
  22
  23         log_setup();
  24
  25         umask(0022);
  26
  27         /* Refuse to run unless we are in an initrd() */
  28         if (!in_initrd())
  29                 return EXIT_SUCCESS;
  30
  31         device = argv[1];
  32
  33         if (stat(device, &st) < 0) {
  34                 log_error_errno(errno, "Failed to stat '%s': %m", device);
  35                 return EXIT_FAILURE;
  36         }
  37
  38         if (!S_ISBLK(st.st_mode)) {
  39                 log_error("Resume device '%s' is not a block device.", device);
  40                 return EXIT_FAILURE;
  41         }
  42
  43         r = write_string_file("/sys/power/resume", FORMAT_DEVNUM(st.st_rdev), WRITE_STRING_FILE_DISABLE_BUFFER);
  44         if (r < 0) {
  45                 log_error_errno(r, "Failed to write '" DEVNUM_FORMAT_STR "' to /sys/power/resume: %m", DEVNUM_FORMAT_VAL(st.st_rdev));
  46                 return EXIT_FAILURE;
  47         }
  48
  49         /*
  50          * The write above shall not return.
  51          *
  52          * However, failed resume is a normal condition (may mean that there is
  53          * no hibernation image).
  54          */
  55
  56         log_info("Could not resume from '%s' (" DEVNUM_FORMAT_STR ").", device, DEVNUM_FORMAT_VAL(st.st_rdev));
  57         return EXIT_SUCCESS;
  58 }