[PATCH] Add --reuse-cmdline

Michael Neuling mikey at neuling.org
Fri May 9 13:13:25 EDT 2008



In message <20080508204943.GA24160 at suse.de> you wrote:
> This patch adds an option "--reuse-cmdline" for people that are lazy in typin
g
> --append="$(cat /proc/cmdline)". The advantage of "--reuse-cmdline" is also t
hat
> it strips off BOOT_IMAGE (since it may not be correct any more) from lilo and
> other boot loaders, and, more important, the crashkernel option in case a
> panic kernel is loaded.
> 
> If you like the option I can also add it for really all architectures. Tested
 only
> with x86-bzImage both the kexec and kdump case.

For ppc64, the default is to reuse the command line.  We should probably
merge functionality.

Either way, this should probably be a generic option, not x86 specific.

Mikey

> 
> 
> Signed-off-by: Bernhard Walle <bwalle at suse.de>
> 
> ---
>  kexec/arch/i386/kexec-bzImage.c       |   12 +++-
>  kexec/arch/i386/kexec-elf-x86.c       |   16 ++++--
>  kexec/arch/i386/kexec-multiboot-x86.c |   12 +++-
>  kexec/arch/x86_64/kexec-elf-x86_64.c  |   16 ++++--
>  kexec/kexec.8                         |   18 +++++++
>  kexec/kexec.c                         |   85 +++++++++++++++++++++++++++++--
---
>  kexec/kexec.h                         |    1 
>  7 files changed, 132 insertions(+), 28 deletions(-)
> 
> --- a/kexec/arch/i386/kexec-bzImage.c
> +++ b/kexec/arch/i386/kexec-bzImage.c
> @@ -89,6 +89,7 @@ void bzImage_usage(void)
>  		"    --real-mode           Use the kernels real mode entry poin
t.\n"
>  		"    --command-line=STRING Set the kernel command line to STRIN
G.\n"
>  		"    --append=STRING       Set the kernel command line to STRIN
G.\n"
> +		"    --reuse-cmdline       Use kernel command line from running
 system.\n"
>  		"    --initrd=FILE         Use FILE as the kernel's initial ram
disk.\n"
>  		"    --ramdisk=FILE        Use FILE as the kernel's initial ram
disk.\n"
>  		);
> @@ -335,14 +336,16 @@ int bzImage_load(int argc, char **argv,
>  	int debug, real_mode_entry;
>  	int opt;
>  	int result;
> -#define OPT_APPEND	(OPT_ARCH_MAX+0)
> -#define OPT_RAMDISK	(OPT_ARCH_MAX+1)
> -#define OPT_REAL_MODE	(OPT_ARCH_MAX+2)
> +#define OPT_APPEND		(OPT_ARCH_MAX+0)
> +#define OPT_REUSE_CMDLINE	(OPT_ARCH_MAX+1)
> +#define OPT_RAMDISK		(OPT_ARCH_MAX+2)
> +#define OPT_REAL_MODE		(OPT_ARCH_MAX+3)

What space updates?

>  	static const struct option options[] = {
>  		KEXEC_ARCH_OPTIONS
>  		{ "debug",		0, 0, OPT_DEBUG },
>  		{ "command-line",	1, 0, OPT_APPEND },
>  		{ "append",		1, 0, OPT_APPEND },
> +		{ "reuse-cmdline",	1, 0, OPT_REUSE_CMDLINE },
>  		{ "initrd",		1, 0, OPT_RAMDISK },
>  		{ "ramdisk",		1, 0, OPT_RAMDISK },
>  		{ "real-mode",		0, 0, OPT_REAL_MODE },
> @@ -374,6 +377,9 @@ int bzImage_load(int argc, char **argv,
>  		case OPT_APPEND:
>  			command_line = optarg;
>  			break;
> +		case OPT_REUSE_CMDLINE:
> +			command_line = get_command_line();
> +			break;
>  		case OPT_RAMDISK:
>  			ramdisk = optarg;
>  			break;
> --- a/kexec/arch/i386/kexec-elf-x86.c
> +++ b/kexec/arch/i386/kexec-elf-x86.c
> @@ -73,6 +73,7 @@ void elf_x86_usage(void)
>  {
>  	printf(	"    --command-line=STRING Set the kernel command line to STRIN
G\n"
>  		"    --append=STRING       Set the kernel command line to STRIN
G\n"
> +		"    --reuse-cmdline       Use kernel command line from running
 system.\n"
>  		"    --initrd=FILE         Use FILE as the kernel's initial ram
disk.\n"
>  		"    --ramdisk=FILE        Use FILE as the kernel's initial ram
disk.\n"
>  		"    --args-linux          Pass linux kernel style options\n"
> @@ -97,16 +98,18 @@ int elf_x86_load(int argc, char **argv,
>  #define ARG_STYLE_LINUX 1
>  #define ARG_STYLE_NONE  2
>  	int opt;
> -#define OPT_APPEND	(OPT_ARCH_MAX+0)
> -#define OPT_RAMDISK	(OPT_ARCH_MAX+1)
> -#define OPT_ARGS_ELF    (OPT_ARCH_MAX+2)
> -#define OPT_ARGS_LINUX  (OPT_ARCH_MAX+3)
> -#define OPT_ARGS_NONE   (OPT_ARCH_MAX+4)
> +#define OPT_APPEND		(OPT_ARCH_MAX+0)
> +#define OPT_REUSE_CMDLINE	(OPT_ARCH_MAX+1)
> +#define OPT_RAMDISK		(OPT_ARCH_MAX+2)
> +#define OPT_ARGS_ELF    	(OPT_ARCH_MAX+3)
> +#define OPT_ARGS_LINUX  	(OPT_ARCH_MAX+4)
> +#define OPT_ARGS_NONE   	(OPT_ARCH_MAX+5)
>  
>  	static const struct option options[] = {
>  		KEXEC_ARCH_OPTIONS
>  		{ "command-line",	1, NULL, OPT_APPEND },
>  		{ "append",		1, NULL, OPT_APPEND },
> +		{ "reuse-cmdline",	1, NULL, OPT_REUSE_CMDLINE },
>  		{ "initrd",		1, NULL, OPT_RAMDISK },
>  		{ "ramdisk",		1, NULL, OPT_RAMDISK },
>  		{ "args-elf",		0, NULL, OPT_ARGS_ELF },
> @@ -138,6 +141,9 @@ int elf_x86_load(int argc, char **argv,
>  		case OPT_APPEND:
>  			command_line = optarg;
>  			break;
> +		case OPT_REUSE_CMDLINE:
> +			command_line = get_command_line();
> +			break;
>  		case OPT_RAMDISK:
>  			ramdisk = optarg;
>  			break;
> --- a/kexec/arch/i386/kexec-multiboot-x86.c
> +++ b/kexec/arch/i386/kexec-multiboot-x86.c
> @@ -129,6 +129,7 @@ void multiboot_x86_usage(void)
>  /* Multiboot-specific options */
>  {
>  	printf("    --command-line=STRING        Set the kernel command line to
 STRING.\n");
> +	printf("    --reuse-cmdline       	 Use kernel command line from r
unning system.\n");
>  	printf("    --module=\"MOD arg1 arg2...\"  Load module MOD with command
-line \"arg1...\"\n");
>  	printf("                                 (can be used multiple times).\
n");
>  }
> @@ -155,13 +156,15 @@ int multiboot_x86_load(int argc, char **
>  	int i;
>  	int opt;
>  	int modules, mod_command_line_space;
> -#define OPT_CL  	(OPT_ARCH_MAX+0)
> -#define OPT_MOD 	(OPT_ARCH_MAX+1)
> -#define OPT_VGA 	(OPT_ARCH_MAX+2)
> +#define OPT_CL  		(OPT_ARCH_MAX+0)
> +#define OPT_REUSE_CMDLINE	(OPT_ARCH_MAX+1)
> +#define OPT_MOD 		(OPT_ARCH_MAX+2)
> +#define OPT_VGA 		(OPT_ARCH_MAX+3)
>  	static const struct option options[] = {
>  		KEXEC_ARCH_OPTIONS
>  		{ "command-line",		1, 0, OPT_CL },
>  		{ "append",			1, 0, OPT_CL },
> +		{ "reuse-cmdline",		1, 0, OPT_REUSE_CMDLINE },
>  		{ "module",			1, 0, OPT_MOD },
>  		{ 0, 				0, 0, 0 },
>  	};
> @@ -194,6 +197,9 @@ int multiboot_x86_load(int argc, char **
>  		case OPT_CL:
>  			command_line = optarg;
>  			break;
> +		case OPT_REUSE_CMDLINE:
> +			command_line = get_command_line();
> +			break;
>  		case OPT_MOD:
>  			modules++;
>  			mod_command_line_space += strlen(optarg) + 1;
> --- a/kexec/arch/x86_64/kexec-elf-x86_64.c
> +++ b/kexec/arch/x86_64/kexec-elf-x86_64.c
> @@ -73,6 +73,7 @@ void elf_x86_64_usage(void)
>  {
>  	printf(	"    --command-line=STRING Set the kernel command line to STRIN
G\n"
>  		"    --append=STRING       Set the kernel command line to STRIN
G\n"
> +		"    --reuse-cmdline       Use kernel command line from running
 system.\n"
>  		"    --initrd=FILE         Use FILE as the kernel's initial ram
disk.\n"
>  		"    --ramdisk=FILE        Use FILE as the kernel's initial ram
disk.\n"
>  		"    --args-linux          Pass linux kernel style options\n"
> @@ -96,16 +97,18 @@ int elf_x86_64_load(int argc, char **arg
>  #define ARG_STYLE_LINUX 1
>  #define ARG_STYLE_NONE  2
>  	int opt;
> -#define OPT_APPEND	(OPT_ARCH_MAX+0)
> -#define OPT_RAMDISK	(OPT_ARCH_MAX+1)
> -#define OPT_ARGS_ELF    (OPT_ARCH_MAX+2)
> -#define OPT_ARGS_LINUX  (OPT_ARCH_MAX+3)
> -#define OPT_ARGS_NONE   (OPT_ARCH_MAX+4)
> +#define OPT_APPEND		(OPT_ARCH_MAX+0)
> +#define OPT_REUSE_CMDLINE	(OPT_ARCH_MAX+1)
> +#define OPT_RAMDISK		(OPT_ARCH_MAX+2)
> +#define OPT_ARGS_ELF		(OPT_ARCH_MAX+3)
> +#define OPT_ARGS_LINUX		(OPT_ARCH_MAX+4)
> +#define OPT_ARGS_NONE		(OPT_ARCH_MAX+5)
>  
>  	static const struct option options[] = {
>  		KEXEC_ARCH_OPTIONS
>  		{ "command-line",	1, NULL, OPT_APPEND },
>  		{ "append",		1, NULL, OPT_APPEND },
> +		{ "reuse-cmdline",	1, NULL, OPT_REUSE_CMDLINE },
>  		{ "initrd",		1, NULL, OPT_RAMDISK },
>  		{ "ramdisk",		1, NULL, OPT_RAMDISK },
>  		{ "args-elf",		0, NULL, OPT_ARGS_ELF },
> @@ -138,6 +141,9 @@ int elf_x86_64_load(int argc, char **arg
>  		case OPT_APPEND:
>  			command_line = optarg;
>  			break;
> +		case OPT_REUSE_CMDLINE:
> +			command_line = get_command_line();
> +			break;
>  		case OPT_RAMDISK:
>  			ramdisk = optarg;
>  			break;
> --- a/kexec/kexec.8
> +++ b/kexec/kexec.8
> @@ -186,6 +186,15 @@ to the kernel command line.
>  Set the kernel command line to
>  .IR string .
>  .TP
> +.BI \-\-reuse-cmdline
> +Use the command line from the running system. When a panic kernel is loaded,
 it
> +strips the
> +.I
> +crashkernel
> +parameter automatically. The
> +.I BOOT_IMAGE
> +parameter is also stripped.
> +.TP
>  .BI \-\-initrd= file
>  Use
>  .I file
> @@ -204,6 +213,15 @@ as the kernel's initial ramdisk.
>  Set the kernel command line to
>  .IR string .
>  .TP
> +.BI \-\-reuse-cmdline
> +Use the command line from the running system. When a panic kernel is loaded,
 it
> +strips the
> +.I
> +crashkernel
> +parameter automatically. The
> +.I BOOT_IMAGE
> +parameter is also stripped.
> +.TP
>  .BI \-\-module= "mod arg1 arg2 ..."
>  Load module
>  .I mod
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -31,6 +31,7 @@
>  #include <unistd.h>
>  #include <fcntl.h>
>  #include <getopt.h>
> +#include <ctype.h>
>  
>  #include "config.h"
>  
> @@ -46,6 +47,7 @@
>  
>  unsigned long long mem_min = 0;
>  unsigned long long mem_max = ULONG_MAX;
> +unsigned long kexec_flags = 0;
>  
>  void die(char *fmt, ...)
>  {
> @@ -792,26 +794,86 @@ static int kexec_loaded(void)
>  	return ret;
>  }
>  
> +/*
> + * Remove parameter from a kernel command line. Helper function by get_comma
nd_line().
> + */
> +static void remove_parameter(char *line, const char *param_name)
> +{
> +	char *start, *end;
> +
> +	start = strstr(line, param_name);
> +
> +	/* parameter not found */
> +	if (!start)
> +		return;
> +
> +	/*
> +	 * check if that's really the start of a parameter and not in
> +	 * the middle of the word
> +	 */
> +	if (start != line && !isspace(*(start-1)))
> +		return;
> +
> +	end = strstr(start, " ");
> +	if (!end)
> +		*start = 0;
> +	else {
> +		memmove(start, end+1, strlen(end));
> +		*(end + strlen(end)) = 0;
> +	}
> +}
> +
> +/*
> + * Returns the contents of the current command line to be used with
> + * --reuse-cmdline option.  The function gets called from architecture speci
fic
> + * code. If we load a panic kernel, that function will strip the
> + * "crashkernel=" option because it does not make sense that the crashkernel
> + * reserves memory for a crashkernel (well, it would not boot since the
> + * amount is exactly the same as the crashkernel has overall memory). Also,
> + * remove the BOOT_IMAGE from lilo (and others) since that doesn't make
> + * sense here any more. The kernel could be different even if we reuse the
> + * commandline.
> + *
> + * The function returns dynamically allocated memory.
> + */
> +char *get_command_line(void)
> +{
> +	FILE *fp;
> +	size_t len;
> +	char *line = NULL;
> +
> +	fp = fopen("/proc/cmdline", "r");
> +	if (!fp)
> +		die("Could not read /proc/cmdline.");
> +	getline(&line, &len, fp);
> +	fclose(fp);
> +
> +	if (line) {
> +		/* strip newline */
> +		*(line + strlen(line) - 1) = 0;
> +
> +		remove_parameter(line, "crashkernel");
> +		if (kexec_flags & KEXEC_ON_CRASH)
> +			remove_parameter(line, "BOOT_IMAGE");
> +	} else
> +		line = strdup("");
> +
> +	return line;
> +}
> +
>  /* check we retained the initrd */
>  void check_reuse_initrd(void)
>  {
> -	FILE * fp;
> -	char * line = NULL;
> -	size_t len = 0;
> -	ssize_t read;
> +	char *line = get_command_line();
>  
> -	fp = fopen("/proc/cmdline", "r");
> -	if (fp == NULL)
> -		die("unable to open /proc/cmdline\n");
> -	read = getline(&line, &len, fp);
>  	if (strstr(line, "retain_initrd") == NULL)
>  		die("unrecoverable error: current boot didn't "
>  		    "retain the initrd for reuse.\n");
> -	if (line)
> -		free(line);
> -	fclose(fp);
> +
> +	free(line);
>  }
>  
> +
>  int main(int argc, char *argv[])
>  {
>  	int do_load = 1;
> @@ -821,7 +883,6 @@ int main(int argc, char *argv[])
>  	int do_ifdown = 0;
>  	int do_unload = 0;
>  	int do_reuse_initrd = 0;
> -	unsigned long kexec_flags = 0;
>  	char *type = 0;
>  	char *endptr;
>  	int opt;
> --- a/kexec/kexec.h
> +++ b/kexec/kexec.h
> @@ -220,6 +220,7 @@ int arch_process_options(int argc, char
>  int arch_compat_trampoline(struct kexec_info *info);
>  void arch_update_purgatory(struct kexec_info *info);
>  int is_crashkernel_mem_reserved(void);
> +char *get_command_line(void);
>  
>  int kexec_iomem_for_each_line(char *match,
>  			      int (*callback)(void *data,
> 
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