From 0ab4dc92278a0f3816e486d6350c6652a72e06c8 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 17 Jul 2007 18:37:02 -0700 Subject: usermodehelper: split setup from execution Rather than having hundreds of variations of call_usermodehelper for various pieces of usermode state which could be set up, split the info allocation and initialization from the actual process execution. This means the general pattern becomes: info = call_usermodehelper_setup(path, argv, envp); /* basic state */ call_usermodehelper_(info, stuff...); /* extra state */ call_usermodehelper_exec(info, wait); /* run process and free info */ This patch introduces wrappers for all the existing calling styles for call_usermodehelper_*, but folds their implementations into one. Signed-off-by: Jeremy Fitzhardinge Cc: Andi Kleen Cc: Rusty Russell Cc: David Howells Cc: Bj?rn Steinbrink Cc: Randy Dunlap --- kernel/kmod.c | 191 +++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 135 insertions(+), 56 deletions(-) (limited to 'kernel') diff --git a/kernel/kmod.c b/kernel/kmod.c index 4d32eb077179..d2dce71115d8 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); -- cgit v1.2.3 From 10a0a8d4e3f6bf2d077f94344441909abe670f5a Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 17 Jul 2007 18:37:02 -0700 Subject: Add common orderly_poweroff() Various pieces of code around the kernel want to be able to trigger an orderly poweroff. This pulls them together into a single implementation. By default the poweroff command is /sbin/poweroff, but it can be set via sysctl: kernel/poweroff_cmd. This is split at whitespace, so it can include command-line arguments. This patch replaces four other instances of invoking either "poweroff" or "shutdown -h now": two sbus drivers, and acpi thermal management. sparc64 has its own "powerd"; still need to determine whether it should be replaced by orderly_poweroff(). Signed-off-by: Jeremy Fitzhardinge Acked-by: Len Brown Signed-off-by: Chris Wright Cc: Andrew Morton Cc: Randy Dunlap Cc: Andi Kleen Cc: Al Viro Cc: Arnd Bergmann Cc: David S. Miller --- kernel/sys.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/sysctl.c | 10 ++++++++++ 2 files changed, 68 insertions(+) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 4d141ae3e802..aeded9ad66ce 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2286,3 +2286,61 @@ asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep, } return err ? -EFAULT : 0; } + +char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; + +static void argv_cleanup(char **argv, char **envp) +{ + argv_free(argv); +} + +/** + * orderly_poweroff - Trigger an orderly system poweroff + * @force: force poweroff if command execution fails + * + * This may be called from any context to trigger a system shutdown. + * If the orderly shutdown fails, it will force an immediate shutdown. + */ +int orderly_poweroff(bool force) +{ + int argc; + char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc); + static char *envp[] = { + "HOME=/", + "PATH=/sbin:/bin:/usr/sbin:/usr/bin", + NULL + }; + int ret = -ENOMEM; + struct subprocess_info *info; + + if (argv == NULL) { + printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n", + __func__, poweroff_cmd); + goto out; + } + + info = call_usermodehelper_setup(argv[0], argv, envp); + if (info == NULL) { + argv_free(argv); + goto out; + } + + call_usermodehelper_setcleanup(info, argv_cleanup); + + ret = call_usermodehelper_exec(info, -1); + + out: + if (ret && force) { + printk(KERN_WARNING "Failed to start orderly shutdown: " + "forcing the issue\n"); + + /* I guess this should try to kick off some daemon to + sync and poweroff asap. Or not even bother syncing + if we're doing an emergency shutdown? */ + emergency_sync(); + kernel_power_off(); + } + + return ret; +} +EXPORT_SYMBOL_GPL(orderly_poweroff); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 7063ebc6db05..44a1d699aad7 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -705,6 +706,15 @@ static ctl_table kern_table[] = { .proc_handler = &proc_dointvec, }, #endif + { + .ctl_name = CTL_UNNUMBERED, + .procname = "poweroff_cmd", + .data = &poweroff_cmd, + .maxlen = POWEROFF_CMD_PATH_LEN, + .mode = 0644, + .proc_handler = &proc_dostring, + .strategy = &sysctl_string, + }, { .ctl_name = 0 } }; -- cgit v1.2.3 From 86313c488a6848b7ec2ba04e74f25f79dd32a0b7 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 17 Jul 2007 18:37:03 -0700 Subject: usermodehelper: Tidy up waiting Rather than using a tri-state integer for the wait flag in call_usermodehelper_exec, define a proper enum, and use that. I've preserved the integer values so that any callers I've missed should still work OK. Signed-off-by: Jeremy Fitzhardinge Cc: James Bottomley Cc: Randy Dunlap Cc: Christoph Hellwig Cc: Andi Kleen Cc: Paul Mackerras Cc: Johannes Berg Cc: Ralf Baechle Cc: Bjorn Helgaas Cc: Joel Becker Cc: Tony Luck Cc: Kay Sievers Cc: Srivatsa Vaddagiri Cc: Oleg Nesterov Cc: David Howells --- kernel/cpuset.c | 2 +- kernel/kmod.c | 27 ++++++++++++++++----------- kernel/sys.c | 2 +- 3 files changed, 18 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index b4796d850140..57e6448b171e 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -516,7 +516,7 @@ static void cpuset_release_agent(const char *pathbuf) envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; envp[i] = NULL; - call_usermodehelper(argv[0], argv, envp, 0); + call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); kfree(pathbuf); } diff --git a/kernel/kmod.c b/kernel/kmod.c index d2dce71115d8..78d365c524ed 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -119,7 +119,7 @@ struct subprocess_info { char **argv; char **envp; struct key *ring; - int wait; + enum umh_wait wait; int retval; struct file *stdin; void (*cleanup)(char **argv, char **envp); @@ -225,7 +225,7 @@ static int wait_for_helper(void *data) sub_info->retval = ret; } - if (sub_info->wait < 0) + if (sub_info->wait == UMH_NO_WAIT) call_usermodehelper_freeinfo(sub_info); else complete(sub_info->complete); @@ -238,26 +238,31 @@ static void __call_usermodehelper(struct work_struct *work) struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); pid_t pid; - int wait = sub_info->wait; + enum umh_wait wait = sub_info->wait; /* CLONE_VFORK: wait until the usermode helper has execve'd * successfully We need the data structures to stay around * until that is done. */ - if (wait) + if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) pid = kernel_thread(wait_for_helper, sub_info, CLONE_FS | CLONE_FILES | SIGCHLD); else pid = kernel_thread(____call_usermodehelper, sub_info, CLONE_VFORK | SIGCHLD); - if (wait < 0) - return; + switch (wait) { + case UMH_NO_WAIT: + break; - if (pid < 0) { + case UMH_WAIT_PROC: + if (pid > 0) + break; sub_info->retval = pid; + /* FALLTHROUGH */ + + case UMH_WAIT_EXEC: complete(sub_info->complete); - } else if (!wait) - complete(sub_info->complete); + } } /** @@ -359,7 +364,7 @@ EXPORT_SYMBOL(call_usermodehelper_stdinpipe); * (ie. it runs with full root capabilities). */ int call_usermodehelper_exec(struct subprocess_info *sub_info, - int wait) + enum umh_wait wait) { DECLARE_COMPLETION_ONSTACK(done); int retval; @@ -378,7 +383,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, sub_info->wait = wait; queue_work(khelper_wq, &sub_info->work); - if (wait < 0) /* task has freed sub_info */ + if (wait == UMH_NO_WAIT) /* task has freed sub_info */ return 0; wait_for_completion(&done); retval = sub_info->retval; diff --git a/kernel/sys.c b/kernel/sys.c index aeded9ad66ce..18987c7f6add 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2327,7 +2327,7 @@ int orderly_poweroff(bool force) call_usermodehelper_setcleanup(info, argv_cleanup); - ret = call_usermodehelper_exec(info, -1); + ret = call_usermodehelper_exec(info, UMH_NO_WAIT); out: if (ret && force) { -- cgit v1.2.3