[uml-devel] [patch 05/12] uml: extend cmd line limits

[uml-devel] [patch 05/12] uml: extend cmd line limits

[blaisorblade]

From: "Catalin(ux aka Dino) BOIE" <util@deuroconsult.ro>, Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>, Jeff Dike <jdike@addtoit.com>
Increase UML command line size. And fix a crash from passing an overly-long
command line to UML.

XXX: check that init can handle 128 params and 128 env. var. The original
patch set this limit to 256, but it seems me too much. Think!

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 linux-2.6.11-paolo/arch/um/include/user_util.h |    2 -
 linux-2.6.11-paolo/arch/um/kernel/um_arch.c    |   34 ++++++++++++++-----------
 linux-2.6.11-paolo/arch/um/kernel/user_util.c  |   15 -----------
 linux-2.6.11-paolo/include/asm-um/setup.h      |    5 ++-
 linux-2.6.11-paolo/init/Kconfig                |    8 +++++
 linux-2.6.11-paolo/init/main.c                 |    4 +-
 6 files changed, 35 insertions(+), 33 deletions(-)

diff -puN arch/um/kernel/um_arch.c~uml-extend-cmd-line-limits arch/um/kernel/um_arch.c
--- linux-2.6.11/arch/um/kernel/um_arch.c~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/um_arch.c	2005-03-21 15:25:42.000000000 +0100
@@ -25,6 +25,7 @@
 #include "asm/user.h"
 #include "ubd_user.h"
 #include "asm/current.h"
+#include "asm/setup.h"
 #include "user_util.h"
 #include "kern_util.h"
 #include "kern.h"
@@ -40,6 +41,20 @@
 
 #define DEFAULT_COMMAND_LINE "root=98:0"
 
+/* Changed in linux_main and setup_arch, which run before SMP is started */
+char command_line[COMMAND_LINE_SIZE] = { 0 };
+
+void add_arg(char *arg)
+{
+	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
+		printf("add_arg: Too much command line!\n");
+		exit(1);
+	}
+	if(strlen(command_line) > 0)
+		strcat(command_line, " ");
+	strcat(command_line, arg);
+}
+
 struct cpuinfo_um boot_cpu_data = { 
 	.loops_per_jiffy	= 0,
 	.ipi_pipe		= { -1, -1 }
@@ -314,9 +329,11 @@ int linux_main(int argc, char **argv)
 		if((i == 1) && (argv[i][0] == ' ')) continue;
 		add = 1;
 		uml_checksetup(argv[i], &add);
-		if(add) add_arg(saved_command_line, argv[i]);
+		if (add)
+			add_arg(argv[i]);
 	}
-	if(have_root == 0) add_arg(saved_command_line, DEFAULT_COMMAND_LINE);
+	if(have_root == 0)
+		add_arg(DEFAULT_COMMAND_LINE);
 
 	mode_tt = force_tt ? 1 : !can_do_skas();
 #ifndef CONFIG_MODE_TT
@@ -432,7 +449,7 @@ void __init setup_arch(char **cmdline_p)
 {
 	notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
 	paging_init();
- 	strcpy(command_line, saved_command_line);
+ 	strlcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
  	*cmdline_p = command_line;
 	setup_hostinfo();
 }
@@ -448,14 +465,3 @@ void __init check_bugs(void)
 void apply_alternatives(void *start, void *end)
 {
 }
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff -puN arch/um/kernel/user_util.c~uml-extend-cmd-line-limits arch/um/kernel/user_util.c
--- linux-2.6.11/arch/um/kernel/user_util.c~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/user_util.c	2005-03-21 15:25:42.000000000 +0100
@@ -31,21 +31,6 @@
 #include "ptrace_user.h"
 #include "uml-config.h"
 
-#define COMMAND_LINE_SIZE _POSIX_ARG_MAX
-
-/* Changed in linux_main and setup_arch, which run before SMP is started */
-char command_line[COMMAND_LINE_SIZE] = { 0 };
-
-void add_arg(char *cmd_line, char *arg)
-{
-	if (strlen(cmd_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
-		printf("add_arg: Too much command line!\n");
-		exit(1);
-	}
-	if(strlen(cmd_line) > 0) strcat(cmd_line, " ");
-	strcat(cmd_line, arg);
-}
-
 void stop(void)
 {
 	while(1) sleep(1000000);
diff -puN include/asm-um/setup.h~uml-extend-cmd-line-limits include/asm-um/setup.h
--- linux-2.6.11/include/asm-um/setup.h~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/include/asm-um/setup.h	2005-03-21 15:25:42.000000000 +0100
@@ -1,6 +1,9 @@
 #ifndef SETUP_H_INCLUDED
 #define SETUP_H_INCLUDED
 
-#define COMMAND_LINE_SIZE 512
+/* POSIX mandated with _POSIX_ARG_MAX that we can rely on 4096 chars in the
+ * command line, so this choice is ok.*/
+
+#define COMMAND_LINE_SIZE 4096
 
 #endif		/* SETUP_H_INCLUDED */
diff -puN init/Kconfig~uml-extend-cmd-line-limits init/Kconfig
--- linux-2.6.11/init/Kconfig~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/init/Kconfig	2005-03-21 15:25:42.000000000 +0100
@@ -55,6 +55,14 @@ config LOCK_KERNEL
 	depends on SMP || PREEMPT
 	default y
 
+config INIT_ENV_ARG_LIMIT
+	int
+	default 32 if !USERMODE
+	default 128 if USERMODE
+	help
+	  This is the value of the two limits on the number of argument and of
+	  env.var passed to init from the kernel command line.
+
 endmenu
 
 menu "General setup"
diff -puN init/main.c~uml-extend-cmd-line-limits init/main.c
--- linux-2.6.11/init/main.c~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/init/main.c	2005-03-21 15:25:42.000000000 +0100
@@ -110,8 +110,8 @@ EXPORT_SYMBOL(system_state);
 /*
  * Boot command-line arguments
  */
-#define MAX_INIT_ARGS 32
-#define MAX_INIT_ENVS 32
+#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
+#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 
 extern void time_init(void);
 /* Default late time init is NULL. archs can override this later. */
diff -puN arch/um/include/user_util.h~uml-extend-cmd-line-limits arch/um/include/user_util.h
--- linux-2.6.11/arch/um/include/user_util.h~uml-extend-cmd-line-limits	2005-03-21 15:25:42.000000000 +0100
+++ linux-2.6.11-paolo/arch/um/include/user_util.h	2005-03-21 15:25:42.000000000 +0100
@@ -67,7 +67,7 @@ extern void *um_kmalloc(int size);
 extern int switcheroo(int fd, int prot, void *from, void *to, int size);
 extern void setup_machinename(char *machine_out);
 extern void setup_hostinfo(void);
-extern void add_arg(char *cmd_line, char *arg);
+extern void add_arg(char *arg);
 extern void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int));
 extern void init_new_thread_signals(int altstack);
 extern void do_exec(int old_pid, int new_pid);
_


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Re: [uml-devel] [patch 05/12] uml: extend cmd line limits

[Rob Landley]

On Tuesday 22 March 2005 11:21 am, blaisorblade@yahoo.it wrote:
> From: "Catalin(ux aka Dino) BOIE" <util@deuroconsult.ro>, Paolo
> 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>, Jeff Dike
> <jdike@addtoit.com> Increase UML command line size. And fix a crash from
> passing an overly-long command line to UML.
>
> XXX: check that init can handle 128 params and 128 env. var. The original
> patch set this limit to 256, but it seems me too much. Think!
>
> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
> ---

Called via xargs, I don't believe there's any limit on the command line 
arguments.

Rob


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[uml-devel] Re: [patch 05/12] uml: extend cmd line limits

[Nuutti Kotivuori]

Rob Landley wrote:
> On Tuesday 22 March 2005 11:21 am, blaisorblade@yahoo.it wrote:
>> From: "Catalin(ux aka Dino) BOIE" <util@deuroconsult.ro>, Paolo
>> 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>, Jeff Dike
>> <jdike@addtoit.com> Increase UML command line size. And fix a crash
>> from passing an overly-long command line to UML.
>>
>> XXX: check that init can handle 128 params and 128 env. var. The
>> original patch set this limit to 256, but it seems me too
>> much. Think!
>>
>> Signed-off-by: Paolo 'Blaisorblade' Giarrusso
>> <blaisorblade@yahoo.it> ---
>
> Called via xargs, I don't believe there's any limit on the command
> line arguments.

There certainly still is. xargs merely passes as many arguments it can
at once, but if necessary, it will run the command multiple times to
do it. Most of the time it doesn't matter if the command is run
multiple times in things like 'xargs grep', but with UML, it most
certainly would.

-- Naked




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Re: [uml-devel] [patch 05/12] uml: extend cmd line limits

[Blaisorblade]

[-- Attachment #1: Type: text/plain, Size: 540 bytes --]

On Tuesday 22 March 2005 22:30, Anthony Brock wrote:
> Blaisor,
>
> Perhaps the error message should be changed from:
>
> "add_arg: Too much command line!\n"
>
> to something like:
>
> "add_arg: Too many command line arguments!\n"
>
> Does this explain the error more clearly? Or am I mistaken?
Yes, I was copying it and didn't notice the message didn't make sense.

Here is the patch, it's queued and will be sent shortly.

-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729
http://www.user-mode-linux.org/~blaisorblade

[-- Attachment #2: uml-correct-message.patch --]
[-- Type: text/x-diff, Size: 928 bytes --]


From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>, "Anthony Brock" <Anthony_Brock@ous.edu>

Replace the message with a more meaningful one. Noted by Anthony Brock.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 linux-2.6.11-paolo/arch/um/kernel/um_arch.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN arch/um/kernel/um_arch.c~uml-correct-message arch/um/kernel/um_arch.c
--- linux-2.6.11/arch/um/kernel/um_arch.c~uml-correct-message	2005-03-24 03:04:59.000000000 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/um_arch.c	2005-03-24 03:05:36.000000000 +0100
@@ -47,7 +47,7 @@ char command_line[COMMAND_LINE_SIZE] = {
 void add_arg(char *arg)
 {
 	if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
-		printf("add_arg: Too much command line!\n");
+		printf("add_arg: Too many command line arguments!\n");
 		exit(1);
 	}
 	if(strlen(command_line) > 0)
_