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Date: Fri, 8 Mar 2013 03:15:08 -0300
From: Lucas De Marchi <lucas.demarchi@...fusion.mobi>
To: lucas.de.marchi@...il.com
Cc: David Howells <dhowells@...hat.com>,
James Morris <james.l.morris@...cle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>,
Lucas De Marchi <lucas.demarchi@...fusion.mobi>,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/7] usermodehelper: Export _exec() and _setup() functions
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.
Signed-off-by: Lucas De Marchi <lucas.demarchi@...fusion.mobi>
---
include/linux/kmod.h | 8 ++++++++
kernel/kmod.c | 56 +++++++++++++++++++++-------------------------------
2 files changed, 31 insertions(+), 33 deletions(-)
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 5398d58..7eebcf5 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -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)
{
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 56dd349..b39f240 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -502,14 +502,28 @@ 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.
+ *
+ * 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,
+ * and return the failure to the calling process
+ *
+ * The cleanup function is just before ethe subprocess_info is about to
+ * be freed. This can be used for freeing the argv and envp. The
+ * Function must be runnable in either a process context or the
+ * context in which call_usermodehelper_exec is called.
*/
-static
struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
- char **envp, gfp_t gfp_mask)
+ char **envp, gfp_t gfp_mask,
+ int (*init)(struct subprocess_info *info, struct cred *new),
+ void (*cleanup)(struct subprocess_info *info),
+ void *data)
{
struct subprocess_info *sub_info;
sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);
@@ -520,38 +534,15 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
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;
}
/**
- * 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,
- * and return the failure to the calling process
- *
- * The cleanup function is just before ethe subprocess_info is about to
- * be freed. This can be used for freeing the argv and envp. The
- * 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,
- 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;
-}
-
-/**
* call_usermodehelper_exec - start a usermode application
* @sub_info: information about the subprocessa
* @wait: wait for the application to finish and return status.
@@ -563,7 +554,6 @@ 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 +605,7 @@ unlock:
helper_unlock();
return retval;
}
+EXPORT_SYMBOL(call_usermodehelper_exec);
/*
* call_usermodehelper_fns() will not run the caller-provided cleanup function
@@ -630,13 +621,12 @@ 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);
--
1.8.1.5
--
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