diff options
| -rw-r--r-- | include/linux/kmod.h | 44 | ||||
| -rw-r--r-- | kernel/kmod.c | 191 |
2 files changed, 176 insertions, 59 deletions
diff --git a/include/linux/kmod.h b/include/linux/kmod.h index 10f505c8431..c4cbe59d9c6 100644 --- a/include/linux/kmod.h +++ b/include/linux/kmod.h @@ -36,13 +36,51 @@ static inline int request_module(const char * name, ...) { return -ENOSYS; } #define try_then_request_module(x, mod...) ((x) ?: (request_module(mod), (x))) struct key; -extern int call_usermodehelper_keys(char *path, char *argv[], char *envp[], - struct key *session_keyring, int wait); +struct file; +struct subprocess_info; + +/* Allocate a subprocess_info structure */ +struct subprocess_info *call_usermodehelper_setup(char *path, + char **argv, char **envp); + +/* Set various pieces of state into the subprocess_info structure */ +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)); + +/* Actually execute the sub-process */ +int call_usermodehelper_exec(struct subprocess_info *info, int wait); + +/* Free the subprocess_info. This is only needed if you're not going + to call call_usermodehelper_exec */ +void call_usermodehelper_freeinfo(struct subprocess_info *info); static inline int call_usermodehelper(char *path, char **argv, char **envp, int wait) { - return call_usermodehelper_keys(path, argv, envp, NULL, wait); + struct subprocess_info *info; + + info = call_usermodehelper_setup(path, argv, envp); + if (info == NULL) + return -ENOMEM; + return call_usermodehelper_exec(info, wait); +} + +static inline int +call_usermodehelper_keys(char *path, char **argv, char **envp, + struct key *session_keyring, int wait) +{ + struct subprocess_info *info; + + info = call_usermodehelper_setup(path, argv, envp); + if (info == NULL) + return -ENOMEM; + + call_usermodehelper_setkeys(info, session_keyring); + return call_usermodehelper_exec(info, wait); } extern void usermodehelper_init(void); diff --git a/kernel/kmod.c b/kernel/kmod.c index 4d32eb07717..d2dce71115d 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -122,6 +122,7 @@ struct subprocess_info { int wait; int retval; struct file *stdin; + void (*cleanup)(char **argv, char **envp); }; /* @@ -180,6 +181,14 @@ static int ____call_usermodehelper(void *data) do_exit(0); } +void call_usermodehelper_freeinfo(struct subprocess_info *info) +{ + if (info->cleanup) + (*info->cleanup)(info->argv, info->envp); + kfree(info); +} +EXPORT_SYMBOL(call_usermodehelper_freeinfo); + /* Keventd can't block, but this (a child) can. */ static int wait_for_helper(void *data) { @@ -217,7 +226,7 @@ static int wait_for_helper(void *data) } if (sub_info->wait < 0) - kfree(sub_info); + call_usermodehelper_freeinfo(sub_info); else complete(sub_info->complete); return 0; @@ -252,11 +261,94 @@ static void __call_usermodehelper(struct work_struct *work) } /** - * call_usermodehelper_keys - start a usermode application - * @path: pathname for the application - * @argv: null-terminated argument list - * @envp: null-terminated environment list - * @session_keyring: session keyring for process (NULL for an empty keyring) + * call_usermodehelper_setup - prepare to call a usermode helper + * @path - path to usermode executable + * @argv - arg vector for process + * @envp - environment for process + * + * Returns either NULL on allocation failure, or a subprocess_info + * structure. This should be passed to call_usermodehelper_exec to + * exec the process and free the structure. + */ +struct subprocess_info *call_usermodehelper_setup(char *path, + char **argv, char **envp) +{ + struct subprocess_info *sub_info; + sub_info = kzalloc(sizeof(struct subprocess_info), GFP_ATOMIC); + if (!sub_info) + goto out; + + INIT_WORK(&sub_info->work, __call_usermodehelper); + sub_info->path = path; + sub_info->argv = argv; + sub_info->envp = envp; + + out: + return sub_info; +} +EXPORT_SYMBOL(call_usermodehelper_setup); + +/** + * call_usermodehelper_setkeys - set the session keys for usermode helper + * @info: a subprocess_info returned by call_usermodehelper_setup + * @session_keyring: the session keyring for the process + */ +void call_usermodehelper_setkeys(struct subprocess_info *info, + struct key *session_keyring) +{ + info->ring = session_keyring; +} +EXPORT_SYMBOL(call_usermodehelper_setkeys); + +/** + * call_usermodehelper_setcleanup - set a cleanup function + * @info: a subprocess_info returned by call_usermodehelper_setup + * @cleanup: a cleanup function + * + * The cleanup function is just befor 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)) +{ + info->cleanup = cleanup; +} +EXPORT_SYMBOL(call_usermodehelper_setcleanup); + +/** + * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin + * @sub_info: a subprocess_info returned by call_usermodehelper_setup + * @filp: set to the write-end of a pipe + * + * This constructs a pipe, and sets the read end to be the stdin of the + * subprocess, and returns the write-end in *@filp. + */ +int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, + struct file **filp) +{ + struct file *f; + + f = create_write_pipe(); + if (IS_ERR(f)) + return PTR_ERR(f); + *filp = f; + + f = create_read_pipe(f); + if (IS_ERR(f)) { + free_write_pipe(*filp); + return PTR_ERR(f); + } + sub_info->stdin = f; + + return 0; +} +EXPORT_SYMBOL(call_usermodehelper_stdinpipe); + +/** + * call_usermodehelper_exec - start a usermode application + * @sub_info: information about the subprocessa * @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 @@ -265,33 +357,24 @@ static void __call_usermodehelper(struct work_struct *work) * Runs a user-space application. The application is started * asynchronously if wait is not set, and runs as a child of keventd. * (ie. it runs with full root capabilities). - * - * Must be called from process context. Returns a negative error code - * if program was not execed successfully, or 0. */ -int call_usermodehelper_keys(char *path, char **argv, char **envp, - struct key *session_keyring, int wait) +int call_usermodehelper_exec(struct subprocess_info *sub_info, + int wait) { DECLARE_COMPLETION_ONSTACK(done); - struct subprocess_info *sub_info; int retval; - if (!khelper_wq) - return -EBUSY; - - if (path[0] == '\0') - return 0; + if (sub_info->path[0] == '\0') { + retval = 0; + goto out; + } - sub_info = kzalloc(sizeof(struct subprocess_info), GFP_ATOMIC); - if (!sub_info) - return -ENOMEM; + if (!khelper_wq) { + retval = -EBUSY; + goto out; + } - 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); @@ -299,47 +382,43 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp, return 0; wait_for_completion(&done); retval = sub_info->retval; - kfree(sub_info); + + out: + call_usermodehelper_freeinfo(sub_info); return retval; } -EXPORT_SYMBOL(call_usermodehelper_keys); +EXPORT_SYMBOL(call_usermodehelper_exec); +/** + * call_usermodehelper_pipe - call a usermode helper process with a pipe stdin + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @filp: set to the write-end of a pipe + * + * This is a simple wrapper which executes a usermode-helper function + * with a pipe as stdin. It is implemented entirely in terms of + * lower-level call_usermodehelper_* functions. + */ int call_usermodehelper_pipe(char *path, char **argv, char **envp, struct file **filp) { - DECLARE_COMPLETION(done); - struct subprocess_info sub_info = { - .work = __WORK_INITIALIZER(sub_info.work, - __call_usermodehelper), - .complete = &done, - .path = path, - .argv = argv, - .envp = envp, - .retval = 0, - }; - struct file *f; - - if (!khelper_wq) - return -EBUSY; + struct subprocess_info *sub_info; + int ret; - if (path[0] == '\0') - return 0; + sub_info = call_usermodehelper_setup(path, argv, envp); + if (sub_info == NULL) + return -ENOMEM; - f = create_write_pipe(); - if (IS_ERR(f)) - return PTR_ERR(f); - *filp = f; + ret = call_usermodehelper_stdinpipe(sub_info, filp); + if (ret < 0) + goto out; - f = create_read_pipe(f); - if (IS_ERR(f)) { - free_write_pipe(*filp); - return PTR_ERR(f); - } - sub_info.stdin = f; + return call_usermodehelper_exec(sub_info, 1); - queue_work(khelper_wq, &sub_info.work); - wait_for_completion(&done); - return sub_info.retval; + out: + call_usermodehelper_freeinfo(sub_info); + return ret; } EXPORT_SYMBOL(call_usermodehelper_pipe); |