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 "log.h"
   9 #include "mkdir.h"
  10 #include "special.h"
  11 #include "string-util.h"
  12 #include "util.h"
  13 #include "virt.h"
  14
  15 /* This generator pulls systemd-bless-boot.service into the initial transaction if the "LoaderBootCountPath" EFI
  16  * variable is set, i.e. the system boots up with boot counting in effect, which means we should mark the boot as
  17  * "good" if we manage to boot up far enough. */
  18
  19 static const char *arg_dest = "/tmp";
  20
  21 int main(int argc, char *argv[]) {
  22         const char *p;
  23
  24         log_set_prohibit_ipc(true);
  25         log_set_target(LOG_TARGET_AUTO);
  26         log_parse_environment();
  27         log_open();
  28
  29         umask(0022);
  30
  31         if (argc > 1 && argc != 4) {
  32                 log_error("This program takes three or no arguments.");
  33                 return EXIT_FAILURE;
  34         }
  35
  36         if (argc > 1)
  37                 arg_dest = argv[2];
  38
  39         if (in_initrd() > 0) {
  40                 log_debug("Skipping generator, running in the initrd.");
  41                 return EXIT_SUCCESS;
  42         }
  43
  44         if (detect_container() > 0) {
  45                 log_debug("Skipping generator, running in a container.");
  46                 return EXIT_SUCCESS;
  47         }
  48
  49         if (!is_efi_boot()) {
  50                 log_debug("Skipping generator, not an EFI boot.");
  51                 return EXIT_SUCCESS;
  52         }
  53
  54         if (access("/sys/firmware/efi/efivars/LoaderBootCountPath-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f", F_OK) < 0) {
  55
  56                 if (errno == ENOENT) {
  57                         log_debug_errno(errno, "Skipping generator, not booted with boot counting in effect.");
  58                         return EXIT_SUCCESS;
  59                 }
  60
  61                 log_error_errno(errno, "Failed to check if LoaderBootCountPath EFI variable exists: %m");
  62                 return EXIT_FAILURE;
  63         }
  64
  65         /* We pull this in from basic.target so that it ends up in all "regular" boot ups, but not in rescue.target or
  66          * even emergency.target. */
  67         p = strjoina(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/systemd-bless-boot.service");
  68         (void) mkdir_parents(p, 0755);
  69         if (symlink(SYSTEM_DATA_UNIT_PATH "/systemd-bless-boot.service", p) < 0) {
  70                 log_error_errno(errno, "Failed to create symlink '%s': %m", p);
  71                 return EXIT_FAILURE;
  72         }
  73
  74         return EXIT_SUCCESS;
  75 }