Merge branch 'audit.b37' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit...
[sfrench/cifs-2.6.git] / kernel / kmod.c
index 3a7379aa31ca6b0a92bec377a23e5c9debed72db..9f923f8ce6a0cd3c225f73eb79c865777ac60967 100644 (file)
@@ -36,6 +36,8 @@
 #include <linux/resource.h>
 #include <asm/uaccess.h>
 
+extern int delete_module(const char *name, unsigned int flags);
+
 extern int max_threads;
 
 static struct workqueue_struct *khelper_wq;
@@ -46,6 +48,7 @@ static struct workqueue_struct *khelper_wq;
        modprobe_path is set via /proc/sys.
 */
 char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
+struct module_kobject kmod_mk;
 
 /**
  * request_module - try to load a kernel module
@@ -75,6 +78,11 @@ int request_module(const char *fmt, ...)
        static atomic_t kmod_concurrent = ATOMIC_INIT(0);
 #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
        static int kmod_loop_msg;
+       char modalias[16 + MODULE_NAME_LEN] = "MODALIAS=";
+       char *uevent_envp[2] = {
+               modalias,
+               NULL
+       };
 
        va_start(args, fmt);
        ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
@@ -82,6 +90,12 @@ int request_module(const char *fmt, ...)
        if (ret >= MODULE_NAME_LEN)
                return -ENAMETOOLONG;
 
+       strcpy(&modalias[strlen("MODALIAS=")], module_name);
+       kobject_uevent_env(&kmod_mk.kobj, KOBJ_CHANGE, uevent_envp);
+
+       if (modprobe_path[0] == '\0')
+               goto out;
+
        /* If modprobe needs a service that is in a module, we get a recursive
         * loop.  Limit the number of running kmod threads to max_threads/2 or
         * MAX_KMOD_CONCURRENT, whichever is the smaller.  A cleaner method
@@ -108,9 +122,115 @@ int request_module(const char *fmt, ...)
 
        ret = call_usermodehelper(modprobe_path, argv, envp, 1);
        atomic_dec(&kmod_concurrent);
+out:
        return ret;
 }
 EXPORT_SYMBOL(request_module);
+
+static ssize_t store_mod_request(struct module_attribute *mattr,
+                                struct module *mod,
+                             const char *buffer, size_t count)
+{
+       char name[MODULE_NAME_LEN];
+       int ret;
+
+       if (count < 1 || count+1 > MODULE_NAME_LEN)
+               return -EINVAL;
+       memcpy(name, buffer, count);
+       name[count] = '\0';
+       if (name[count-1] == '\n')
+               name[count-1] = '\0';
+
+       ret = request_module(name);
+       if (ret < 0)
+               return ret;
+       return count;
+}
+
+static struct module_attribute mod_request = {
+       .attr = { .name = "mod_request", .mode = S_IWUSR, .owner = THIS_MODULE },
+       .store = store_mod_request,
+};
+
+#ifdef CONFIG_MODULE_UNLOAD
+static ssize_t store_mod_unload(struct module_attribute *mattr,
+                           struct module *mod,
+                           const char *buffer, size_t count)
+{
+       char name[MODULE_NAME_LEN];
+       int ret;
+
+       if (count < 1 || count+1 > MODULE_NAME_LEN)
+               return -EINVAL;
+       memcpy(name, buffer, count);
+       name[count] = '\0';
+       if (name[count-1] == '\n')
+               name[count-1] = '\0';
+
+       ret = delete_module(name, O_NONBLOCK);
+       if (ret < 0)
+               return ret;
+       return count;
+}
+
+static struct module_attribute mod_unload = {
+       .attr = { .name = "mod_unload", .mode = S_IWUSR, .owner = THIS_MODULE },
+       .store = store_mod_unload,
+};
+#endif
+
+static ssize_t show_mod_request_helper(struct module_attribute *mattr,
+                                      struct module *mod,
+                                      char *buffer)
+{
+       return sprintf(buffer, "%s\n", modprobe_path);
+}
+
+static ssize_t store_mod_request_helper(struct module_attribute *mattr,
+                                       struct module *mod,
+                                       const char *buffer, size_t count)
+{
+       if (count < 1 || count+1 > KMOD_PATH_LEN)
+               return -EINVAL;
+       memcpy(modprobe_path, buffer, count);
+       modprobe_path[count] = '\0';
+       if (modprobe_path[count-1] == '\n')
+               modprobe_path[count-1] = '\0';
+       return count;
+}
+
+static struct module_attribute mod_request_helper = {
+       .attr = {
+               .name = "mod_request_helper",
+               .mode = S_IWUSR | S_IRUGO,
+               .owner = THIS_MODULE
+       },
+       .show = show_mod_request_helper,
+       .store = store_mod_request_helper,
+};
+
+void __init kmod_sysfs_init(void)
+{
+       int ret;
+
+       kmod_mk.mod = THIS_MODULE;
+       kobj_set_kset_s(&kmod_mk, module_subsys);
+       kobject_set_name(&kmod_mk.kobj, "kmod");
+       kobject_init(&kmod_mk.kobj);
+       ret = kobject_add(&kmod_mk.kobj);
+       if (ret < 0)
+               goto out;
+
+       ret = sysfs_create_file(&kmod_mk.kobj, &mod_request_helper.attr);
+       ret = sysfs_create_file(&kmod_mk.kobj, &mod_request.attr);
+#ifdef CONFIG_MODULE_UNLOAD
+       ret = sysfs_create_file(&kmod_mk.kobj, &mod_unload.attr);
+#endif
+
+       kobject_uevent(&kmod_mk.kobj, KOBJ_ADD);
+out:
+       return;
+}
 #endif /* CONFIG_KMOD */
 
 struct subprocess_info {
@@ -217,7 +337,10 @@ static int wait_for_helper(void *data)
                        sub_info->retval = ret;
        }
 
-       complete(sub_info->complete);
+       if (sub_info->wait < 0)
+               kfree(sub_info);
+       else
+               complete(sub_info->complete);
        return 0;
 }
 
@@ -239,6 +362,9 @@ static void __call_usermodehelper(struct work_struct *work)
                pid = kernel_thread(____call_usermodehelper, sub_info,
                                    CLONE_VFORK | SIGCHLD);
 
+       if (wait < 0)
+               return;
+
        if (pid < 0) {
                sub_info->retval = pid;
                complete(sub_info->complete);
@@ -253,6 +379,9 @@ static void __call_usermodehelper(struct work_struct *work)
  * @envp: null-terminated environment list
  * @session_keyring: session keyring for process (NULL for an empty keyring)
  * @wait: wait for the application to finish and return status.
+ *        when -1 don't wait at all, but you get no useful error back when
+ *        the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
  *
  * Runs a user-space application.  The application is started
  * asynchronously if wait is not set, and runs as a child of keventd.
@@ -265,17 +394,8 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
                             struct key *session_keyring, int wait)
 {
        DECLARE_COMPLETION_ONSTACK(done);
-       struct subprocess_info sub_info = {
-               .work           = __WORK_INITIALIZER(sub_info.work,
-                                                    __call_usermodehelper),
-               .complete       = &done,
-               .path           = path,
-               .argv           = argv,
-               .envp           = envp,
-               .ring           = session_keyring,
-               .wait           = wait,
-               .retval         = 0,
-       };
+       struct subprocess_info *sub_info;
+       int retval;
 
        if (!khelper_wq)
                return -EBUSY;
@@ -283,9 +403,25 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
        if (path[0] == '\0')
                return 0;
 
-       queue_work(khelper_wq, &sub_info.work);
+       sub_info = kzalloc(sizeof(struct subprocess_info),  GFP_ATOMIC);
+       if (!sub_info)
+               return -ENOMEM;
+
+       INIT_WORK(&sub_info->work, __call_usermodehelper);
+       sub_info->complete = &done;
+       sub_info->path = path;
+       sub_info->argv = argv;
+       sub_info->envp = envp;
+       sub_info->ring = session_keyring;
+       sub_info->wait = wait;
+
+       queue_work(khelper_wq, &sub_info->work);
+       if (wait < 0) /* task has freed sub_info */
+               return 0;
        wait_for_completion(&done);
-       return sub_info.retval;
+       retval = sub_info->retval;
+       kfree(sub_info);
+       return retval;
 }
 EXPORT_SYMBOL(call_usermodehelper_keys);