[PATCH 2/4] Add --initrd argument to mdadm

[Jes.Sorensen@redhat.com]

From: Jes Sorensen <Jes.Sorensen@redhat.com>

When --initrd is parsed, mdadm will change the first character of
argv[0] to '@'. This is used to signal to systemd that mdadm was
launched from initramfs and should not be shut down before returning
to the initramfs.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 ReadMe.c |    3 +++
 mdadm.c  |   10 ++++++++++
 mdadm.h  |    1 +
 3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/ReadMe.c b/ReadMe.c
index 9aa798b..49dc04f 100644
--- a/ReadMe.c
+++ b/ReadMe.c
@@ -111,6 +111,7 @@ struct option long_options[] = {
     {"kill-subarray", 1, 0, KillSubarray},
     {"update-subarray", 1, 0, UpdateSubarray},
     {"udev-rules", 2, 0, UdevRules},
+    {"initrd", 0, 0, InitrdOpt},
 
     /* synonyms */
     {"monitor",   0, 0, 'F'},
@@ -268,6 +269,8 @@ char OptionHelp[] =
 "  --query       -Q   : Display general information about how a\n"
 "                       device relates to the md driver\n"
 "  --auto-detect      : Start arrays auto-detected by the kernel\n"
+"  --initrd           : Set first character of argv[0] to @ to indicate the\n"
+"                       application was launched from initrd.\n"
 ;
 /*
 "\n"
diff --git a/mdadm.c b/mdadm.c
index f07fac2..c0ccf55 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -174,6 +174,16 @@ int main(int argc, char *argv[])
 				homehost = optarg;
 			continue;
 
+		/*
+		 * --initrd sets first char of argv[0] to @. This is used
+		 * by systemd to signal that the tast was launched from
+		 * initrd/initramfs and should be preserved during shutdown
+		 */
+		case InitrdOpt:
+			c = argv[0];
+			c[0] = '@';
+			continue;
+
 		case ':':
 		case '?':
 			fputs(Usage, stderr);
diff --git a/mdadm.h b/mdadm.h
index 381ef86..d1ac1e8 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -321,6 +321,7 @@ enum special_options {
 	UdevRules,
 	FreezeReshape,
 	Continue,
+	InitrdOpt,
 };
 
 /* structures read from config file */
-- 
1.7.8.3