[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: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 842f801..5c63c53 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -122,6 +122,7 @@
struct key *ring;
int wait;
int retval;
+ struct file *stdin;
};
/*
@@ -145,12 +146,26 @@
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);
retval = -EPERM;
if (current->fs->root)
- retval = execve(sub_info->path, sub_info->argv,sub_info->envp);
+ retval = execve(sub_info->path, sub_info->argv, sub_info->envp);
/* Exec failed? */
sub_info->retval = retval;
@@ -268,6 +283,44 @@
}
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");