src/basic/initrd-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <unistd.h>
   4
   5 #include "env-util.h"
   6 #include "errno-util.h"
   7 #include "initrd-util.h"
   8 #include "parse-util.h"
   9 #include "stat-util.h"
  10 #include "string-util.h"
  11
  12 static int saved_in_initrd = -1;
  13
  14 bool in_initrd(void) {
  15         int r;
  16
  17         if (saved_in_initrd >= 0)
  18                 return saved_in_initrd;
  19
  20         /* If /etc/initrd-release exists, we're in an initrd.
  21          * This can be overridden by setting SYSTEMD_IN_INITRD=0|1.
  22          */
  23
  24         r = getenv_bool_secure("SYSTEMD_IN_INITRD");
  25         if (r < 0 && r != -ENXIO)
  26                 log_debug_errno(r, "Failed to parse $SYSTEMD_IN_INITRD, ignoring: %m");
  27
  28         if (r >= 0)
  29                 saved_in_initrd = r > 0;
  30         else {
  31                 r = RET_NERRNO(access("/etc/initrd-release", F_OK));
  32                 if (r < 0 && r != -ENOENT)
  33                         log_debug_errno(r, "Failed to check if /etc/initrd-release exists, assuming it does not: %m");
  34                 saved_in_initrd = r >= 0;
  35         }
  36
  37         return saved_in_initrd;
  38 }
  39
  40 void in_initrd_force(bool value) {
  41         saved_in_initrd = value;
  42 }