UBUNTU: SAUCE: add option to hand off all kernel parameters to init

BugLink: http://bugs.launchpad.net/bugs/586386

Some init packages such as upstart find having all of the kernel parameters
passed in useful.  Currently they have to open up /proc/cmdline and
reparse that to obtain this information.  Add a kernel configuration
option to enable passing of all options.

Note, enabling this option will reduce the chances that a fallback from
/sbin/init to /bin/bash or /bin/sh will succeed.  Though it should be
noted that there are commonly unknown options present which would already
break this fallback.  init=/bin/foo provides explicit control over options
which is unaffected by this change.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>

2 files changed, 33 insertions, 7 deletions

diff --git a/init/Kconfig b/init/Kconfig
index d47ace970a1..3fa57a9d013 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -76,6 +76,13 @@ config INIT_ENV_ARG_LIMIT
 	  Maximum of each of the number of arguments and environment
 	  variables passed to init from the kernel command line.
 
+config INIT_PASS_ALL_PARAMS
+	bool "Pass all (known and unknown) kernel parameters to init"
+	default n
+	help
+	  Pass all kernel command line parameters to init, this includes
+	  those consumed by kernel modules.  This is useful for upstart
+	  based systems.  If in doubt say N.
 
 config CROSS_COMPILE
 	string "Cross-compiler tool prefix"
diff --git a/init/main.c b/init/main.c
index 1c691f94ffc..5d96791e281 100644
--- a/init/main.c
+++ b/init/main.c
@@ -113,6 +113,11 @@ EXPORT_SYMBOL(system_state);
  */
 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
+#ifdef CONFIG_INIT_PASS_ALL_PARAMS
+#define INIT_PASS_FUNCTION pass_all_bootoptions
+#else
+#define INIT_PASS_FUNCTION pass_unknown_bootoptions
+#endif
 
 extern void time_init(void);
 /* Default late time init is NULL. archs can override this later. */
@@ -216,10 +221,11 @@ 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).
+ * Select boot options to hand to init.  If all is set hand off them all
+ * otherwise only hand off unused ones which do not apply to modules
+ * (modprobe will find them in /proc/cmdline).
  */
-static int __init unknown_bootoption(char *param, char *val)
+static int __init pass_bootoption(char *param, char *val, int all)
 {
 	/* Change NUL term back to "=", to make "param" the whole string. */
 	if (val) {
@@ -235,11 +241,11 @@ static int __init unknown_bootoption(char *param, char *val)
 	}
 
 	/* Handle obsolete-style parameters */
-	if (obsolete_checksetup(param))
+	if (obsolete_checksetup(param) && !all)
 		return 0;
 
 	/* Unused module parameter. */
-	if (strchr(param, '.') && (!val || strchr(param, '.') < val))
+	if (!all && strchr(param, '.') && (!val || strchr(param, '.') < val))
 		return 0;
 
 	if (panic_later)
@@ -270,6 +276,16 @@ static int __init unknown_bootoption(char *param, char *val)
 	}
 	return 0;
 }
+static int __init pass_unknown_bootoptions(char *param, char *val, int known)
+{
+	if (known)
+		return 0;
+	return pass_bootoption(param, val, 0);
+}
+static int __init pass_all_bootoptions(char *param, char *val, int known)
+{
+	return pass_bootoption(param, val, 1);
+}
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
 int __read_mostly debug_pagealloc_enabled = 0;
@@ -376,10 +392,13 @@ static noinline void __init_refok rest_init(void)
 }
 
 /* Check for early params. */
-static int __init do_early_param(char *param, char *val)
+static int __init do_early_param(char *param, char *val, int known)
 {
 	const struct obs_kernel_param *p;
 
+	if (known)
+		return 0;
+
 	for (p = __setup_start; p < __setup_end; p++) {
 		if ((p->early && strcmp(param, p->str) == 0) ||
 		    (strcmp(param, "console") == 0 &&
@@ -500,7 +519,7 @@ asmlinkage void __init start_kernel(void)
 	parse_early_param();
 	parse_args("Booting kernel", static_command_line, __start___param,
 		   __stop___param - __start___param,
-		   &unknown_bootoption);
+		   &INIT_PASS_FUNCTION);
 	/*
 	 * These use large bootmem allocations and must precede
 	 * kmem_cache_init()