Commit be907e49 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[PATCH] call_usermodehelper retval fix

The reworked firmware loader in the DVB patches needs the fix to the
call_usermodehelper() return value. 

From: Rusty Russell <rusty@rustcorp.com.au>

MODULE_ALIAS_BLOCK() and MODULE_ALIAS_CHAR() define aliases of form
"XXX-<major>-<minor>", so we should probe for modules using this form.
Unfortunately in 2.4, block aliases were "XXX-<major>" and char aliases
were of both forms.

Ideally, all modules would now be using MODULE_ALIAS() macros to define
their aliases, and the old configuration files wouldn't matter as much. 
Unfortunately, this hasn't happened, so we make request_module() return the
exit status of modprobe, and then do fallback when probing for char and
block devices.

(Kudos to Chris Wright, I stole his kernel_thread flags).
parent 6a429be8
...@@ -296,6 +296,8 @@ extern int blk_dev_init(void); ...@@ -296,6 +296,8 @@ extern int blk_dev_init(void);
static struct kobject *base_probe(dev_t dev, int *part, void *data) static struct kobject *base_probe(dev_t dev, int *part, void *data)
{ {
if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
/* Make old-style 2.4 aliases work */
request_module("block-major-%d", MAJOR(dev)); request_module("block-major-%d", MAJOR(dev));
return NULL; return NULL;
} }
......
...@@ -434,7 +434,9 @@ void cdev_init(struct cdev *cdev, struct file_operations *fops) ...@@ -434,7 +434,9 @@ void cdev_init(struct cdev *cdev, struct file_operations *fops)
static struct kobject *base_probe(dev_t dev, int *part, void *data) static struct kobject *base_probe(dev_t dev, int *part, void *data)
{ {
request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)); if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
/* Make old-style 2.4 aliases work */
request_module("char-major-%d", MAJOR(dev));
return NULL; return NULL;
} }
......
...@@ -24,6 +24,8 @@ ...@@ -24,6 +24,8 @@
#include <linux/compiler.h> #include <linux/compiler.h>
#ifdef CONFIG_KMOD #ifdef CONFIG_KMOD
/* modprobe exit status on success, -ve on error. Return value
* usually useless though. */
extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2))); extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2)));
#else #else
static inline int request_module(const char * name, ...) { return -ENOSYS; } static inline int request_module(const char * name, ...) { return -ENOSYS; }
......
...@@ -182,16 +182,21 @@ static int wait_for_helper(void *data) ...@@ -182,16 +182,21 @@ static int wait_for_helper(void *data)
{ {
struct subprocess_info *sub_info = data; struct subprocess_info *sub_info = data;
pid_t pid; pid_t pid;
struct k_sigaction sa;
/* Install a handler: if SIGCLD isn't handled sys_wait4 won't
* populate the status, but will return -ECHILD. */
sa.sa.sa_handler = SIG_IGN;
sa.sa.sa_flags = 0;
siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD));
do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
allow_signal(SIGCHLD);
sub_info->retval = 0;
pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD);
if (pid < 0) if (pid < 0)
sub_info->retval = pid; sub_info->retval = pid;
else else
/* We don't have a SIGCHLD signal handler, so this sys_wait4(pid, &sub_info->retval, 0, NULL);
* always returns -ECHILD, but the important thing is
* that it blocks. */
sys_wait4(pid, NULL, 0, NULL);
complete(sub_info->complete); complete(sub_info->complete);
return 0; return 0;
...@@ -210,7 +215,7 @@ static void __call_usermodehelper(void *data) ...@@ -210,7 +215,7 @@ static void __call_usermodehelper(void *data)
* until that is done. */ * until that is done. */
if (sub_info->wait) if (sub_info->wait)
pid = kernel_thread(wait_for_helper, sub_info, pid = kernel_thread(wait_for_helper, sub_info,
CLONE_KERNEL | SIGCHLD); CLONE_FS | CLONE_FILES | SIGCHLD);
else else
pid = kernel_thread(____call_usermodehelper, sub_info, pid = kernel_thread(____call_usermodehelper, sub_info,
CLONE_VFORK | SIGCHLD); CLONE_VFORK | SIGCHLD);
......
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