Patchwork [1/2] UBUNTU: SAUCE: add option to hand off all kernel parameters to init

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Submitter Andy Whitcroft
Date June 17, 2010, 9:46 a.m.
Message ID <1276768008-16696-2-git-send-email-apw@canonical.com>
Download mbox | patch
Permalink /patch/55999/
State Accepted
Delegated to: Leann Ogasawara
Headers show

Comments

Andy Whitcroft - June 17, 2010, 9:46 a.m.
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>
---
 include/linux/moduleparam.h |    2 +-
 init/Kconfig                |    7 +++++++
 init/main.c                 |   33 ++++++++++++++++++++++++++-------
 kernel/params.c             |   20 ++++++++++++++------
 4 files changed, 48 insertions(+), 14 deletions(-)

Patch

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 82a9124..c425126 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -144,7 +144,7 @@  extern int parse_args(const char *name,
 		      char *args,
 		      struct kernel_param *params,
 		      unsigned num,
-		      int (*unknown)(char *param, char *val));
+		      int (*handle)(char *param, char *val, int known));
 
 /* Called by module remove. */
 #ifdef CONFIG_SYSFS
diff --git a/init/Kconfig b/init/Kconfig
index ce68380..fc438f8 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -75,6 +75,13 @@  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 de016bc..1b1d50e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -107,6 +107,11 @@  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. */
@@ -265,10 +270,11 @@  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) {
@@ -284,11 +290,11 @@  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)
@@ -319,6 +325,16 @@  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;
@@ -450,10 +466,13 @@  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)
 {
 	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 &&
@@ -574,7 +593,7 @@  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()
diff --git a/kernel/params.c b/kernel/params.c
index 0b30ecd..0267fd1 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -51,22 +51,30 @@  static int parse_one(char *param,
 		     char *val,
 		     struct kernel_param *params, 
 		     unsigned num_params,
-		     int (*handle_unknown)(char *param, char *val))
+		     int (*handle_arg)(char *param, char *val, int known))
 {
 	unsigned int i;
 
 	/* Find parameter */
 	for (i = 0; i < num_params; i++) {
 		if (parameq(param, params[i].name)) {
+			if (handle_arg) {
+				int ret;
+				DEBUGP("Valid argument: calling %p\n",
+				       handle_arg);
+				ret = handle_arg(param, val, 1);
+				if (ret)
+					return ret;
+			}
 			DEBUGP("They are equal!  Calling %p\n",
 			       params[i].set);
 			return params[i].set(val, &params[i]);
 		}
 	}
 
-	if (handle_unknown) {
-		DEBUGP("Unknown argument: calling %p\n", handle_unknown);
-		return handle_unknown(param, val);
+	if (handle_arg) {
+		DEBUGP("Unknown argument: calling %p\n", handle_arg);
+		return handle_arg(param, val, 0);
 	}
 
 	DEBUGP("Unknown argument `%s'\n", param);
@@ -130,7 +138,7 @@  int parse_args(const char *name,
 	       char *args,
 	       struct kernel_param *params,
 	       unsigned num,
-	       int (*unknown)(char *param, char *val))
+	       int (*handle_arg)(char *param, char *val, int arg))
 {
 	char *param, *val;
 
@@ -145,7 +153,7 @@  int parse_args(const char *name,
 
 		args = next_arg(args, &param, &val);
 		irq_was_disabled = irqs_disabled();
-		ret = parse_one(param, val, params, num, unknown);
+		ret = parse_one(param, val, params, num, handle_arg);
 		if (irq_was_disabled && !irqs_disabled()) {
 			printk(KERN_WARNING "parse_args(): option '%s' enabled "
 					"irq's!\n", param);