3 files changed, 73 insertions, 35 deletions

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index facb27fe7de0..f9edf63e90ea 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -23,6 +23,7 @@
 #include <linux/stddef.h>
 #include <linux/errno.h>
 #include <linux/compiler.h>
+#include <linux/workqueue.h>
 
 #define KMOD_PATH_LEN 256
 
@@ -45,7 +46,27 @@ static inline int request_module_nowait(const char *name, ...) { return -ENOSYS;
 
 struct key;
 struct file;
-struct subprocess_info;
+
+enum umh_wait {
+        UMH_NO_WAIT = -1,       /* don't wait at all */
+        UMH_WAIT_EXEC = 0,      /* wait for the exec, but not the process */
+        UMH_WAIT_PROC = 1,      /* wait for the process to complete */
+};
+
+struct subprocess_info {
+        struct work_struct work;
+        struct completion *complete;
+        struct cred *cred;
+        char *path;
+        char **argv;
+        char **envp;
+        enum umh_wait wait;
+        int retval;
+        struct file *stdin;
+        int (*init)(struct subprocess_info *info);
+        void (*cleanup)(struct subprocess_info *info);
+        void *data;
+};
 
 /* Allocate a subprocess_info structure */
 struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,
@@ -56,14 +77,10 @@ void call_usermodehelper_setkeys(struct subprocess_info *info,
                                  struct key *session_keyring);
 int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info,
                                   struct file **filp);
-void call_usermodehelper_setcleanup(struct subprocess_info *info,
-                                    void (*cleanup)(char **argv, char **envp));
-
-enum umh_wait {
-        UMH_NO_WAIT = -1,       /* don't wait at all */
-        UMH_WAIT_EXEC = 0,      /* wait for the exec, but not the process */
-        UMH_WAIT_PROC = 1,      /* wait for the process to complete */
-};
+void call_usermodehelper_setfns(struct subprocess_info *info,
+                    int (*init)(struct subprocess_info *info),
+                    void (*cleanup)(struct subprocess_info *info),
+                    void *data);
 
 /* Actually execute the sub-process */
 int call_usermodehelper_exec(struct subprocess_info *info, enum umh_wait wait);
@@ -73,18 +90,32 @@ int call_usermodehelper_exec(struct subprocess_info *info, enum umh_wait wait);
 void call_usermodehelper_freeinfo(struct subprocess_info *info);
 
 static inline int
-call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)
+call_usermodehelper_fns(char *path, char **argv, char **envp,
+                        enum umh_wait wait,
+                        int (*init)(struct subprocess_info *info),
+                        void (*cleanup)(struct subprocess_info *), void *data)
 {
         struct subprocess_info *info;
         gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
 
         info = call_usermodehelper_setup(path, argv, envp, gfp_mask);
+
         if (info == NULL)
                 return -ENOMEM;
+
+        call_usermodehelper_setfns(info, init, cleanup, data);
+
         return call_usermodehelper_exec(info, wait);
 }
 
 static inline int
+call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)
+{
+        return call_usermodehelper_fns(path, argv, envp, wait,
+                                       NULL, NULL, NULL);
+}
+
+static inline int
 call_usermodehelper_keys(char *path, char **argv, char **envp,
                          struct key *session_keyring, enum umh_wait wait)
 {
diff --git a/kernel/kmod.c b/kernel/kmod.c
index bf0e231d9702..531ef62cf536 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -116,27 +116,16 @@ int __request_module(bool wait, const char *fmt, ...)
 
         trace_module_request(module_name, wait, _RET_IP_);
 
-        ret = call_usermodehelper(modprobe_path, argv, envp,
-                        wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
+        ret = call_usermodehelper_fns(modprobe_path, argv, envp,
+                        wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC,
+                        NULL, NULL, NULL);
+
         atomic_dec(&kmod_concurrent);
         return ret;
 }
 EXPORT_SYMBOL(__request_module);
 #endif /* CONFIG_MODULES */
 
-struct subprocess_info {
-        struct work_struct work;
-        struct completion *complete;
-        struct cred *cred;
-        char *path;
-        char **argv;
-        char **envp;
-        enum umh_wait wait;
-        int retval;
-        struct file *stdin;
-        void (*cleanup)(char **argv, char **envp);
-};
-
 /*
  * This is the task which runs the usermode application
  */
@@ -184,9 +173,16 @@ static int ____call_usermodehelper(void *data)
          */
         set_user_nice(current, 0);
 
+        if (sub_info->init) {
+                retval = sub_info->init(sub_info);
+                if (retval)
+                        goto fail;
+        }
+
         retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
 
         /* Exec failed? */
+fail:
         sub_info->retval = retval;
         do_exit(0);
 }
@@ -194,7 +190,7 @@ static int ____call_usermodehelper(void *data)
 void call_usermodehelper_freeinfo(struct subprocess_info *info)
 {
         if (info->cleanup)
-                (*info->cleanup)(info->argv, info->envp);
+                (*info->cleanup)(info);
         if (info->cred)
                 put_cred(info->cred);
         kfree(info);
@@ -406,21 +402,31 @@ void call_usermodehelper_setkeys(struct subprocess_info *info,
 EXPORT_SYMBOL(call_usermodehelper_setkeys);
 
 /**
- * call_usermodehelper_setcleanup - set a cleanup function
+ * call_usermodehelper_setfns - set a cleanup/init function
  * @info: a subprocess_info returned by call_usermodehelper_setup
  * @cleanup: a cleanup function
+ * @init: an init function
+ * @data: arbitrary context sensitive data
+ *
+ * The init function is used to customize the helper process prior to
+ * exec.  A non-zero return code causes the process to error out, exit,
+ * and return the failure to the calling process
  *
- * The cleanup function is just befor ethe subprocess_info is about to
+ * The cleanup function is just before ethe subprocess_info is about to
  * be freed.  This can be used for freeing the argv and envp.  The
  * Function must be runnable in either a process context or the
  * context in which call_usermodehelper_exec is called.
  */
-void call_usermodehelper_setcleanup(struct subprocess_info *info,
-                                    void (*cleanup)(char **argv, char **envp))
+void call_usermodehelper_setfns(struct subprocess_info *info,
+                    int (*init)(struct subprocess_info *info),
+                    void (*cleanup)(struct subprocess_info *info),
+                    void *data)
 {
         info->cleanup = cleanup;
+        info->init = init;
+        info->data = data;
 }
-EXPORT_SYMBOL(call_usermodehelper_setcleanup);
+EXPORT_SYMBOL(call_usermodehelper_setfns);
 
 /**
  * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin
@@ -515,7 +521,8 @@ int call_usermodehelper_pipe(char *path, char **argv, char **envp,
         struct subprocess_info *sub_info;
         int ret;
 
-        sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL);
+        sub_info = call_usermodehelper_setup(path, argv, envp,
+                                             GFP_KERNEL);
         if (sub_info == NULL)
                 return -ENOMEM;
 
diff --git a/kernel/sys.c b/kernel/sys.c
index 0d36d889c74d..e83ddbbaf89d 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1632,9 +1632,9 @@ SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
 
 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
 
-static void argv_cleanup(char **argv, char **envp)
+static void argv_cleanup(struct subprocess_info *info)
 {
-        argv_free(argv);
+        argv_free(info->argv);
 }
 
 /**
@@ -1668,7 +1668,7 @@ int orderly_poweroff(bool force)
                 goto out;
         }
 
-        call_usermodehelper_setcleanup(info, argv_cleanup);
+        call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
 
         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);