module tool with 2.6.9 limitation issue

module tool with 2.6.9 limitation issue

[yiding_wang]

I am using moudle-init-tools-3.1-pre6 with kernel 2.6.9. The new insmod seems have restrictions which failed using parameters to load a driver module.

My module parameter is in the form of modname="*************** ****", a quite long one.
Run - insmod modname.o modname="*********** *******" (with a script), it complains about the space and treats the string next to the space to be a "Unknown parameter".

By replacing the space with any character, then it complains 
"modname: string parameter too long"

Reducing the length of the parameter to less than 1k character works fine.

Same long parameter string wit space in between works fine under 2.4.25 with original insmod.

Questions:
1, Is this a bug or new insmod has restrictions? 
2, If it is restriction on special character such as space, or limitation on parameter length, then why and what is the limit? 
3, If insmod has limitation, then what is better way to pass long parameter with some special character? 

Thanks!

Eddie

Re: module tool with 2.6.9 limitation issue

[Randy.Dunlap]

[-- Attachment #1: Type: text/plain, Size: 1861 bytes --]

yiding_wang@agilent.com wrote:
> I am using moudle-init-tools-3.1-pre6 with kernel 2.6.9. The new insmod seems have restrictions which failed using parameters to load a driver module.
> 
> My module parameter is in the form of modname="*************** ****", a quite long one.
> Run - insmod modname.o modname="*********** *******" (with a script), it complains about the space and treats the string next to the space to be a "Unknown parameter".
> 
> By replacing the space with any character, then it complains 
> "modname: string parameter too long"

Patch for that one is attached.  It might be overkill,
but it works with this patch (as long as parameter value length
is <= 1024 -- not that I tried one of that length).

Rusty or anyone else, where do the quotes come from?
Here's what I enter:
insmod test_module modprm="this test"

but the kernel sees this parameter string:
"modprm=this test"
(with the quotation marks).
Who/what moved the quotation marks?  Is bash doing any of that?
I don't see it in insmod or modprobe (with a quick look).

> Reducing the length of the parameter to less than 1k character works fine.

Right, parameter value length cannot be > 1024.

> Same long parameter string wit space in between works fine under 2.4.25 with original insmod.
> 
> Questions:
> 1, Is this a bug or new insmod has restrictions? 

The limit is actually in linux/kernel/params.c, not in insmod.
It seems a little arbitrary, but a parameter that long also seems
quite excessive.  Just break it into multiple parameters.

> 2, If it is restriction on special character such as space, or limitation on parameter length, then why and what is the limit? 

Just 1024 bytes in total length.

> 3, If insmod has limitation, then what is better way to pass long parameter with some special character? 

Just break it into multiple parameters....

-- 
~Randy

[-- Attachment #2: modprm_quoted.patch --]
[-- Type: text/x-patch, Size: 1175 bytes --]

linux-2610-rc1-bk21
description

Signed-off-by: Randy Dunlap <rddunlap@osdl.org>

diffstat:=
 kernel/params.c |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diff -Naurp ./kernel/params.c~modprm_quoted ./kernel/params.c
--- ./kernel/params.c~modprm_quoted	2004-11-11 15:13:26.000000000 -0800
+++ ./kernel/params.c	2004-11-11 19:42:36.714124784 -0800
@@ -77,10 +77,16 @@ static int parse_one(char *param,
 static char *next_arg(char *args, char **param, char **val)
 {
 	unsigned int i, equals = 0;
-	int in_quote = 0;
+	int in_quote = 0, quoted = 0;
+	char *next;
 
 	/* Chew any extra spaces */
 	while (*args == ' ') args++;
+	if (*args == '"') {
+		args++;
+		in_quote = 1;
+		quoted = 1;
+	}
 
 	for (i = 0; args[i]; i++) {
 		if (args[i] == ' ' && !in_quote)
@@ -106,13 +112,16 @@ static char *next_arg(char *args, char *
 			if (args[i-1] == '"')
 				args[i-1] = '\0';
 		}
+		if (quoted && args[i-1] == '"')
+			args[i-1] = '\0';
 	}
 
 	if (args[i]) {
 		args[i] = '\0';
-		return args + i + 1;
+		next = args + i + 1;
 	} else
-		return args + i;
+		next = args + i;
+	return next;
 }
 
 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */

[PATCH] handle quoted module parameters

[Randy.Dunlap]

[-- Attachment #1: Type: text/plain, Size: 362 bytes --]

Here's a patch with better description.


Fix module parameter quote handling.
Module parameter strings (with spaces) are quoted like so:
"modprm=this test"
and not like this:
modprm="this test"

Signed-off-by: Randy Dunlap <rddunlap@osdl.org>

diffstat:=
  kernel/params.c |   15 ++++++++++++---
  1 files changed, 12 insertions(+), 3 deletions(-)


-- 
~Randy

[-- Attachment #2: modprm_quoted.patch --]
[-- Type: text/x-patch, Size: 991 bytes --]


diff -Naurp ./kernel/params.c~modprm_quoted ./kernel/params.c
--- ./kernel/params.c~modprm_quoted	2004-11-11 15:13:26.000000000 -0800
+++ ./kernel/params.c	2004-11-11 19:42:36.714124784 -0800
@@ -77,10 +77,16 @@ static int parse_one(char *param,
 static char *next_arg(char *args, char **param, char **val)
 {
 	unsigned int i, equals = 0;
-	int in_quote = 0;
+	int in_quote = 0, quoted = 0;
+	char *next;
 
 	/* Chew any extra spaces */
 	while (*args == ' ') args++;
+	if (*args == '"') {
+		args++;
+		in_quote = 1;
+		quoted = 1;
+	}
 
 	for (i = 0; args[i]; i++) {
 		if (args[i] == ' ' && !in_quote)
@@ -106,13 +112,16 @@ static char *next_arg(char *args, char *
 			if (args[i-1] == '"')
 				args[i-1] = '\0';
 		}
+		if (quoted && args[i-1] == '"')
+			args[i-1] = '\0';
 	}
 
 	if (args[i]) {
 		args[i] = '\0';
-		return args + i + 1;
+		next = args + i + 1;
 	} else
-		return args + i;
+		next = args + i;
+	return next;
 }
 
 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */

Re: [PATCH] handle quoted module parameters

[Rusty Russell]

On Thu, 2004-11-11 at 20:16 -0800, Randy.Dunlap wrote: 
> Here's a patch with better description.
> 
> 
> Fix module parameter quote handling.
> Module parameter strings (with spaces) are quoted like so:
> "modprm=this test"
> and not like this:
> modprm="this test"

Well, the quote handling in insmod was ripped out after 3.0, exactly
because it was broken like this.  But modprobe will use the latter form,
since it will paste it straight from the modprobe.conf file (which needs
quotes in options lines).

Hope that clarifies,
Rusty.
PS. module-init-tools 3.1 just out...
-- 
A bad analogy is like a leaky screwdriver -- Richard Braakman