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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: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Reviewed-by: Oleg 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lucas De Marchi 2013-04-30 15:28:02 -07:00 committed by Linus Torvalds
parent 17afab1de4
commit 938e4b22e2
2 changed files with 35 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/kmod.h
View File

@ -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)
{

63
kernel/kmod.c
View File

@ -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,
int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *info),
void *data)
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 @@ unlock:
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);