linux-kernel - [PATCH] init: fix bug where environment vars can't be passed via boot args

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Date:	Fri, 6 Apr 2012 12:53:50 -0400
From:	Chris Metcalf <cmetcalf@...era.com>
To:	Pawel Moll <pawel.moll@....com>, Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Stanislaw Gruszka <sgruszka@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] init: fix bug where environment vars can't be passed via boot args

Commit 026cee0086f had the side-effect of dropping the '=' from
the unknown boot arguments that are passed to init as environment
variables.  This is because parse_args() puts a NUL in the string
where the '=' was when it passes the "param" and "val" pointers
to the parsing subfunctions.  Previously, unknown_bootoption() was
the last parse_args() subfunction to run, and it carefully put back
the '=' character.  Now ignore_unknown_bootoption() is the last
one to run, and it wasn't doing the necessary repair, so the
envp params ended up with the embedded NUL and were no longer
seen as valid environment variables by init.

Signed-off-by: Chris Metcalf <cmetcalf@...era.com>
---
 init/main.c |   25 +++++++++++++------------
 1 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/init/main.c b/init/main.c
index 9d454f0..44b2433 100644
--- a/init/main.c
+++ b/init/main.c
@@ -225,13 +225,9 @@ static int __init loglevel(char *str)
 
 early_param("loglevel", loglevel);
 
-/*
- * Unknown boot options get handed to init, unless they look like
- * unused parameters (modprobe will find them in /proc/cmdline).
- */
-static int __init unknown_bootoption(char *param, char *val)
+/* Change NUL term back to "=", to make "param" the whole string. */
+static int __init repair_env_string(char *param, char *val)
 {
-	/* Change NUL term back to "=", to make "param" the whole string. */
 	if (val) {
 		/* param=val or param="val"? */
 		if (val == param+strlen(param)+1)
@@ -243,6 +239,16 @@ static int __init unknown_bootoption(char *param, char *val)
 		} else
 			BUG();
 	}
+	return 0;
+}
+
+/*
+ * Unknown boot options get handed to init, unless they look like
+ * unused parameters (modprobe will find them in /proc/cmdline).
+ */
+static int __init unknown_bootoption(char *param, char *val)
+{
+	repair_env_string(param, val);
 
 	/* Handle obsolete-style parameters */
 	if (obsolete_checksetup(param))
@@ -732,11 +738,6 @@ static char *initcall_level_names[] __initdata = {
 	"late parameters",
 };
 
-static int __init ignore_unknown_bootoption(char *param, char *val)
-{
-	return 0;
-}
-
 static void __init do_initcall_level(int level)
 {
 	extern const struct kernel_param __start___param[], __stop___param[];
@@ -747,7 +748,7 @@ static void __init do_initcall_level(int level)
 		   static_command_line, __start___param,
 		   __stop___param - __start___param,
 		   level, level,
-		   ignore_unknown_bootoption);
+		   repair_env_string);
 
 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 		do_one_initcall(*fn);
-- 
1.6.5.2

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