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Commit 938e4b22 authored by Lucas De Marchi's avatar Lucas De Marchi Committed by Linus Torvalds
Browse files

usermodehelper: export call_usermodehelper_exec() and call_usermodehelper_setup() 



call_usermodehelper_setup() + call_usermodehelper_exec() need to be
called instead of call_usermodehelper_fns() when the cleanup function
needs to be called even when an ENOMEM error occurs.  In this case using
call_usermodehelper_fns() the user can't distinguish if the cleanup
function was called or not.

[akpm@linux-foundation.org: export call_usermodehelper_setup() to modules]
Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 17afab1d

include/linux/kmod.h

+8 −0
Original line number Diff line number Diff line
@@ -71,6 +71,14 @@ call_usermodehelper_fns(char *path, char **argv, char **envp, int wait, 
			int (*init)(struct subprocess_info *info, struct cred *new),

			void (*cleanup)(struct subprocess_info *), void *data);



extern struct subprocess_info *

call_usermodehelper_setup(char *path, char **argv, char **envp, gfp_t gfp_mask,

			  int (*init)(struct subprocess_info *info, struct cred *new),

			  void (*cleanup)(struct subprocess_info *), void *data);



extern int

call_usermodehelper_exec(struct subprocess_info *info, int wait);



static inline int

call_usermodehelper(char *path, char **argv, char **envp, int wait)

{

kernel/kmod.c

+24 −33
Original line number Diff line number Diff line
@@ -502,34 +502,13 @@ static void helper_unlock(void) 
 * @argv: arg vector for process

 * @envp: environment for process

 * @gfp_mask: gfp mask for memory allocation

 * @cleanup: a cleanup function

 * @init: an init function

 * @data: arbitrary context sensitive data

 *

 * Returns either %NULL on allocation failure, or a subprocess_info

 * structure.  This should be passed to call_usermodehelper_exec to

 * exec the process and free the structure.

 */

static

struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,

						  char **envp, gfp_t gfp_mask)

{

	struct subprocess_info *sub_info;

	sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);

	if (!sub_info)

		goto out;



	INIT_WORK(&sub_info->work, __call_usermodehelper);

	sub_info->path = path;

	sub_info->argv = argv;

	sub_info->envp = envp;

  out:

	return sub_info;

}



/**

 * call_usermodehelper_setfns - set a cleanup/init function

 * @info: a subprocess_info returned by call_usermodehelper_setup

 * @cleanup: a cleanup function

 * @init: an init function

 * @data: arbitrary context sensitive data

 *

 * The init function is used to customize the helper process prior to

 * exec.  A non-zero return code causes the process to error out, exit,
@@ -540,16 +519,29 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, 
 * Function must be runnable in either a process context or the

 * context in which call_usermodehelper_exec is called.

 */

static

void call_usermodehelper_setfns(struct subprocess_info *info,

struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,

		char **envp, gfp_t gfp_mask,

		int (*init)(struct subprocess_info *info, struct cred *new),

		void (*cleanup)(struct subprocess_info *info),

		void *data)

{

	info->cleanup = cleanup;

	info->init = init;

	info->data = data;

	struct subprocess_info *sub_info;

	sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);

	if (!sub_info)

		goto out;



	INIT_WORK(&sub_info->work, __call_usermodehelper);

	sub_info->path = path;

	sub_info->argv = argv;

	sub_info->envp = envp;



	sub_info->cleanup = cleanup;

	sub_info->init = init;

	sub_info->data = data;

  out:

	return sub_info;

}

EXPORT_SYMBOL(call_usermodehelper_setup);



/**

 * call_usermodehelper_exec - start a usermode application
@@ -563,7 +555,6 @@ void call_usermodehelper_setfns(struct subprocess_info *info, 
 * asynchronously if wait is not set, and runs as a child of keventd.

 * (ie. it runs with full root capabilities).

 */

static

int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)

{

	DECLARE_COMPLETION_ONSTACK(done);
@@ -615,6 +606,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) 
	helper_unlock();

	return retval;

}

EXPORT_SYMBOL(call_usermodehelper_exec);



/*

 * call_usermodehelper_fns() will not run the caller-provided cleanup function
@@ -630,13 +622,12 @@ int call_usermodehelper_fns( 
	struct subprocess_info *info;

	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;



	info = call_usermodehelper_setup(path, argv, envp, gfp_mask);

	info = call_usermodehelper_setup(path, argv, envp, gfp_mask,

					 init, cleanup, data);



	if (info == NULL)

		return -ENOMEM;



	call_usermodehelper_setfns(info, init, cleanup, data);



	return call_usermodehelper_exec(info, wait);

}

EXPORT_SYMBOL(call_usermodehelper_fns);