Add $SYSTEMD_IN_INITRD=yes|no override for debugging

diff --git a/docs/ENVIRONMENT.md b/docs/ENVIRONMENT.md
index 9d598a6693189c2c1aa286de7ec44c0d57bcb688..ec804c9c8589e371c91ce4101e739d372740b4c4 100644 (file)
--- a/docs/ENVIRONMENT.md
+++ b/docs/ENVIRONMENT.md
@@ -37,6 +37,10 @@ All tools:
   useful for debugging, in order to test generators and other code against
   specific kernel command lines.
 
+* `$SYSTEMD_IN_INITRD` — takes a boolean. If set, overrides initrd detection.
+  This is useful for debugging and testing initrd-only programs in the main
+  system.
+
 * `$SYSTEMD_BUS_TIMEOUT=SECS` — specifies the maximum time to wait for method call
   completion. If no time unit is specified, assumes seconds. The usual other units
   are understood, too (us, ms, s, min, h, d, w, month, y). If it is not set or set

diff --git a/src/basic/util.c b/src/basic/util.c
index 081c63c898c12318a3c7379e82a3ddf33710d21a..0da963f4af876548846ebc02860aadcefdb07003 100644 (file)
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -23,6 +23,7 @@
 #include "def.h"
 #include "device-nodes.h"
 #include "dirent-util.h"
+#include "env-util.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "format-util.h"
@@ -106,6 +107,7 @@ int prot_from_flags(int flags) {
 
 bool in_initrd(void) {
         struct statfs s;
+        int r;
 
         if (saved_in_initrd >= 0)
                 return saved_in_initrd;
@@ -120,9 +122,16 @@ bool in_initrd(void) {
          * emptying when transititioning to the main systemd.
          */
 
-        saved_in_initrd = access("/etc/initrd-release", F_OK) >= 0 &&
-                          statfs("/", &s) >= 0 &&
-                          is_temporary_fs(&s);
+        r = getenv_bool_secure("SYSTEMD_IN_INITRD");
+        if (r < 0 && r != -ENXIO)
+                log_debug_errno(r, "Failed to parse $SYSTEMD_IN_INITRD, ignoring: %m");
+
+        if (r >= 0)
+                saved_in_initrd = r > 0;
+        else
+                saved_in_initrd = access("/etc/initrd-release", F_OK) >= 0 &&
+                                  statfs("/", &s) >= 0 &&
+                                  is_temporary_fs(&s);
 
         return saved_in_initrd;
 }