src/boot/bless-boot-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <sys/stat.h>
   5 #include <unistd.h>
   6
   7 #include "efivars.h"
   8 #include "generator.h"
   9 #include "log.h"
  10 #include "mkdir.h"
  11 #include "special.h"
  12 #include "string-util.h"
  13 #include "util.h"
  14 #include "virt.h"
  15
  16 /* This generator pulls systemd-bless-boot.service into the initial transaction if the "LoaderBootCountPath" EFI
  17  * variable is set, i.e. the system boots up with boot counting in effect, which means we should mark the boot as
  18  * "good" if we manage to boot up far enough. */
  19
  20 static const char *arg_dest = "/tmp";
  21
  22 int main(int argc, char *argv[]) {
  23         const char *p;
  24
  25         log_setup_generator();
  26
  27         if (argc > 1 && argc != 4) {
  28                 log_error("This program takes three or no arguments.");
  29                 return EXIT_FAILURE;
  30         }
  31
  32         if (argc > 1)
  33                 arg_dest = argv[2];
  34
  35         if (in_initrd() > 0) {
  36                 log_debug("Skipping generator, running in the initrd.");
  37                 return EXIT_SUCCESS;
  38         }
  39
  40         if (detect_container() > 0) {
  41                 log_debug("Skipping generator, running in a container.");
  42                 return EXIT_SUCCESS;
  43         }
  44
  45         if (!is_efi_boot()) {
  46                 log_debug("Skipping generator, not an EFI boot.");
  47                 return EXIT_SUCCESS;
  48         }
  49
  50         if (access("/sys/firmware/efi/efivars/LoaderBootCountPath-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f", F_OK) < 0) {
  51
  52                 if (errno == ENOENT) {
  53                         log_debug_errno(errno, "Skipping generator, not booted with boot counting in effect.");
  54                         return EXIT_SUCCESS;
  55                 }
  56
  57                 log_error_errno(errno, "Failed to check if LoaderBootCountPath EFI variable exists: %m");
  58                 return EXIT_FAILURE;
  59         }
  60
  61         /* We pull this in from basic.target so that it ends up in all "regular" boot ups, but not in rescue.target or
  62          * even emergency.target. */
  63         p = strjoina(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/systemd-bless-boot.service");
  64         (void) mkdir_parents(p, 0755);
  65         if (symlink(SYSTEM_DATA_UNIT_PATH "/systemd-bless-boot.service", p) < 0) {
  66                 log_error_errno(errno, "Failed to create symlink '%s': %m", p);
  67                 return EXIT_FAILURE;
  68         }
  69
  70         return EXIT_SUCCESS;
  71 }