1 files changed, 150 insertions, 14 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 3a7379aa31ca..9f923f8ce6a0 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -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);