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Commit e239ca54 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

[PATCH] Create call_usermodehelper_pipe() 



A new member in the ever growing family of call_usermode* functions is
born.  The new call_usermodehelper_pipe() function allows to pipe data to
the stdin of the called user mode progam and behaves otherwise like the
normal call_usermodehelp() (except that it always waits for the child to
finish)

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d6cbd281

include/linux/kmod.h

+4 −0
Original line number Diff line number Diff line
@@ -47,4 +47,8 @@ call_usermodehelper(char *path, char **argv, char **envp, int wait) 


extern void usermodehelper_init(void);



struct file;

extern int call_usermodehelper_pipe(char *path, char *argv[], char *envp[],

				    struct file **filp);



#endif /* __LINUX_KMOD_H__ */

kernel/kmod.c

+54 −1
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ struct subprocess_info { 
	struct key *ring;

	int wait;

	int retval;

	struct file *stdin;

};



/*
@@ -145,6 +146,20 @@ static int ____call_usermodehelper(void *data) 


	key_put(old_session);



	/* Install input pipe when needed */

	if (sub_info->stdin) {

		struct files_struct *f = current->files;

		struct fdtable *fdt;

		/* no races because files should be private here */

		sys_close(0);

		fd_install(0, sub_info->stdin);

		spin_lock(&f->file_lock);

		fdt = files_fdtable(f);

		FD_SET(0, fdt->open_fds);

		FD_CLR(0, fdt->close_on_exec);

		spin_unlock(&f->file_lock);

	}



	/* We can run anywhere, unlike our parent keventd(). */

	set_cpus_allowed(current, CPU_MASK_ALL);
@@ -268,6 +283,44 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp, 
}

EXPORT_SYMBOL(call_usermodehelper_keys);



int call_usermodehelper_pipe(char *path, char **argv, char **envp,

			     struct file **filp)

{

	DECLARE_COMPLETION(done);

	struct subprocess_info sub_info = {

		.complete	= &done,

		.path		= path,

		.argv		= argv,

		.envp		= envp,

		.retval		= 0,

	};

	struct file *f;

	DECLARE_WORK(work, __call_usermodehelper, &sub_info);



	if (!khelper_wq)

		return -EBUSY;



	if (path[0] == '\0')

		return 0;



	f = create_write_pipe();

	if (!f)

		return -ENOMEM;

	*filp = f;



	f = create_read_pipe(f);

	if (!f) {

		free_write_pipe(*filp);

		return -ENOMEM;

	}

	sub_info.stdin = f;



	queue_work(khelper_wq, &work);

	wait_for_completion(&done);

	return sub_info.retval;

}

EXPORT_SYMBOL(call_usermodehelper_pipe);



void __init usermodehelper_init(void)

{

	khelper_wq = create_singlethread_workqueue("khelper");