Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | kmod, the new module loader (replaces kerneld) |
| 3 | Kirk Petersen |
| 4 | |
| 5 | Reorganized not to be a daemon by Adam Richter, with guidance |
| 6 | from Greg Zornetzer. |
| 7 | |
| 8 | Modified to avoid chroot and file sharing problems. |
| 9 | Mikael Pettersson |
| 10 | |
| 11 | Limit the concurrent number of kmod modprobes to catch loops from |
| 12 | "modprobe needs a service that is in a module". |
| 13 | Keith Owens <kaos@ocs.com.au> December 1999 |
| 14 | |
| 15 | Unblock all signals when we exec a usermode process. |
| 16 | Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 |
| 17 | |
| 18 | call_usermodehelper wait flag, and remove exec_usermodehelper. |
| 19 | Rusty Russell <rusty@rustcorp.com.au> Jan 2003 |
| 20 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/module.h> |
| 22 | #include <linux/sched.h> |
| 23 | #include <linux/syscalls.h> |
| 24 | #include <linux/unistd.h> |
| 25 | #include <linux/kmod.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/slab.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/completion.h> |
| 28 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 29 | #include <linux/fdtable.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/workqueue.h> |
| 31 | #include <linux/security.h> |
| 32 | #include <linux/mount.h> |
| 33 | #include <linux/kernel.h> |
| 34 | #include <linux/init.h> |
Andi Kleen | d025c9d | 2006-09-30 23:29:28 -0700 | [diff] [blame] | 35 | #include <linux/resource.h> |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 36 | #include <linux/notifier.h> |
| 37 | #include <linux/suspend.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <asm/uaccess.h> |
| 39 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 40 | #include <trace/events/module.h> |
| 41 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | extern int max_threads; |
| 43 | |
| 44 | static struct workqueue_struct *khelper_wq; |
| 45 | |
Johannes Berg | a1ef5ad | 2008-07-08 19:00:17 +0200 | [diff] [blame] | 46 | #ifdef CONFIG_MODULES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | /* |
| 49 | modprobe_path is set via /proc/sys. |
| 50 | */ |
| 51 | char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; |
| 52 | |
| 53 | /** |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 54 | * __request_module - try to load a kernel module |
| 55 | * @wait: wait (or not) for the operation to complete |
Randy Dunlap | bd4207c | 2009-01-06 14:42:39 -0800 | [diff] [blame] | 56 | * @fmt: printf style format string for the name of the module |
| 57 | * @...: arguments as specified in the format string |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | * |
| 59 | * Load a module using the user mode module loader. The function returns |
| 60 | * zero on success or a negative errno code on failure. Note that a |
| 61 | * successful module load does not mean the module did not then unload |
| 62 | * and exit on an error of its own. Callers must check that the service |
| 63 | * they requested is now available not blindly invoke it. |
| 64 | * |
| 65 | * If module auto-loading support is disabled then this function |
| 66 | * becomes a no-operation. |
| 67 | */ |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 68 | int __request_module(bool wait, const char *fmt, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | { |
| 70 | va_list args; |
| 71 | char module_name[MODULE_NAME_LEN]; |
| 72 | unsigned int max_modprobes; |
| 73 | int ret; |
| 74 | char *argv[] = { modprobe_path, "-q", "--", module_name, NULL }; |
| 75 | static char *envp[] = { "HOME=/", |
| 76 | "TERM=linux", |
| 77 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", |
| 78 | NULL }; |
| 79 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
| 80 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ |
| 81 | static int kmod_loop_msg; |
| 82 | |
Eric Paris | 9188499 | 2009-08-13 09:44:57 -0400 | [diff] [blame] | 83 | ret = security_kernel_module_request(); |
| 84 | if (ret) |
| 85 | return ret; |
| 86 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | va_start(args, fmt); |
| 88 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); |
| 89 | va_end(args); |
| 90 | if (ret >= MODULE_NAME_LEN) |
| 91 | return -ENAMETOOLONG; |
| 92 | |
| 93 | /* If modprobe needs a service that is in a module, we get a recursive |
| 94 | * loop. Limit the number of running kmod threads to max_threads/2 or |
| 95 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method |
| 96 | * would be to run the parents of this process, counting how many times |
| 97 | * kmod was invoked. That would mean accessing the internals of the |
| 98 | * process tables to get the command line, proc_pid_cmdline is static |
| 99 | * and it is not worth changing the proc code just to handle this case. |
| 100 | * KAO. |
| 101 | * |
| 102 | * "trace the ppid" is simple, but will fail if someone's |
| 103 | * parent exits. I think this is as good as it gets. --RR |
| 104 | */ |
| 105 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); |
| 106 | atomic_inc(&kmod_concurrent); |
| 107 | if (atomic_read(&kmod_concurrent) > max_modprobes) { |
| 108 | /* We may be blaming an innocent here, but unlikely */ |
| 109 | if (kmod_loop_msg++ < 5) |
| 110 | printk(KERN_ERR |
| 111 | "request_module: runaway loop modprobe %s\n", |
| 112 | module_name); |
| 113 | atomic_dec(&kmod_concurrent); |
| 114 | return -ENOMEM; |
| 115 | } |
| 116 | |
Li Zefan | 7ead8b8 | 2009-08-17 16:56:28 +0800 | [diff] [blame] | 117 | trace_module_request(module_name, wait, _RET_IP_); |
| 118 | |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 119 | ret = call_usermodehelper(modprobe_path, argv, envp, |
| 120 | wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | atomic_dec(&kmod_concurrent); |
| 122 | return ret; |
| 123 | } |
Arjan van de Ven | acae051 | 2009-02-08 10:42:01 -0800 | [diff] [blame] | 124 | EXPORT_SYMBOL(__request_module); |
Rusty Russell | 118a906 | 2008-10-17 02:38:36 -0500 | [diff] [blame] | 125 | #endif /* CONFIG_MODULES */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
| 127 | struct subprocess_info { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 128 | struct work_struct work; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | struct completion *complete; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 130 | struct cred *cred; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | char *path; |
| 132 | char **argv; |
| 133 | char **envp; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 134 | enum umh_wait wait; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | int retval; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 136 | struct file *stdin; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 137 | void (*cleanup)(char **argv, char **envp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | }; |
| 139 | |
| 140 | /* |
| 141 | * This is the task which runs the usermode application |
| 142 | */ |
| 143 | static int ____call_usermodehelper(void *data) |
| 144 | { |
| 145 | struct subprocess_info *sub_info = data; |
| 146 | int retval; |
| 147 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 148 | BUG_ON(atomic_read(&sub_info->cred->usage) != 1); |
| 149 | |
| 150 | /* Unblock all signals */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | spin_lock_irq(¤t->sighand->siglock); |
| 152 | flush_signal_handlers(current, 1); |
| 153 | sigemptyset(¤t->blocked); |
| 154 | recalc_sigpending(); |
| 155 | spin_unlock_irq(¤t->sighand->siglock); |
| 156 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 157 | /* Install the credentials */ |
| 158 | commit_creds(sub_info->cred); |
| 159 | sub_info->cred = NULL; |
David Howells | 7888e7f | 2005-06-23 22:00:51 -0700 | [diff] [blame] | 160 | |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 161 | /* Install input pipe when needed */ |
| 162 | if (sub_info->stdin) { |
| 163 | struct files_struct *f = current->files; |
| 164 | struct fdtable *fdt; |
| 165 | /* no races because files should be private here */ |
| 166 | sys_close(0); |
| 167 | fd_install(0, sub_info->stdin); |
| 168 | spin_lock(&f->file_lock); |
| 169 | fdt = files_fdtable(f); |
| 170 | FD_SET(0, fdt->open_fds); |
| 171 | FD_CLR(0, fdt->close_on_exec); |
| 172 | spin_unlock(&f->file_lock); |
Andi Kleen | d025c9d | 2006-09-30 23:29:28 -0700 | [diff] [blame] | 173 | |
| 174 | /* and disallow core files too */ |
| 175 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0}; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 176 | } |
| 177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | /* We can run anywhere, unlike our parent keventd(). */ |
Rusty Russell | 1a2142a | 2009-03-30 22:05:10 -0600 | [diff] [blame] | 179 | set_cpus_allowed_ptr(current, cpu_all_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | |
Jan Engelhardt | b73a7e7 | 2007-05-08 00:28:24 -0700 | [diff] [blame] | 181 | /* |
| 182 | * Our parent is keventd, which runs with elevated scheduling priority. |
| 183 | * Avoid propagating that into the userspace child. |
| 184 | */ |
| 185 | set_user_nice(current, 0); |
| 186 | |
Jan Blunck | db74ece | 2008-02-14 19:34:29 -0800 | [diff] [blame] | 187 | retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | |
| 189 | /* Exec failed? */ |
| 190 | sub_info->retval = retval; |
| 191 | do_exit(0); |
| 192 | } |
| 193 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 194 | void call_usermodehelper_freeinfo(struct subprocess_info *info) |
| 195 | { |
| 196 | if (info->cleanup) |
| 197 | (*info->cleanup)(info->argv, info->envp); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 198 | if (info->cred) |
| 199 | put_cred(info->cred); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 200 | kfree(info); |
| 201 | } |
| 202 | EXPORT_SYMBOL(call_usermodehelper_freeinfo); |
| 203 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | /* Keventd can't block, but this (a child) can. */ |
| 205 | static int wait_for_helper(void *data) |
| 206 | { |
| 207 | struct subprocess_info *sub_info = data; |
| 208 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | |
| 210 | /* Install a handler: if SIGCLD isn't handled sys_wait4 won't |
| 211 | * populate the status, but will return -ECHILD. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | allow_signal(SIGCHLD); |
| 213 | |
| 214 | pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); |
| 215 | if (pid < 0) { |
| 216 | sub_info->retval = pid; |
| 217 | } else { |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 218 | int ret; |
| 219 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | /* |
| 221 | * Normally it is bogus to call wait4() from in-kernel because |
| 222 | * wait4() wants to write the exit code to a userspace address. |
| 223 | * But wait_for_helper() always runs as keventd, and put_user() |
| 224 | * to a kernel address works OK for kernel threads, due to their |
| 225 | * having an mm_segment_t which spans the entire address space. |
| 226 | * |
| 227 | * Thus the __user pointer cast is valid here. |
| 228 | */ |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 229 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
| 230 | |
| 231 | /* |
| 232 | * If ret is 0, either ____call_usermodehelper failed and the |
| 233 | * real error code is already in sub_info->retval or |
| 234 | * sub_info->retval is 0 anyway, so don't mess with it then. |
| 235 | */ |
| 236 | if (ret) |
| 237 | sub_info->retval = ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | } |
| 239 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 240 | if (sub_info->wait == UMH_NO_WAIT) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 241 | call_usermodehelper_freeinfo(sub_info); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 242 | else |
| 243 | complete(sub_info->complete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | return 0; |
| 245 | } |
| 246 | |
| 247 | /* This is run by khelper thread */ |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 248 | static void __call_usermodehelper(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 250 | struct subprocess_info *sub_info = |
| 251 | container_of(work, struct subprocess_info, work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | pid_t pid; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 253 | enum umh_wait wait = sub_info->wait; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 255 | BUG_ON(atomic_read(&sub_info->cred->usage) != 1); |
| 256 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | /* CLONE_VFORK: wait until the usermode helper has execve'd |
| 258 | * successfully We need the data structures to stay around |
| 259 | * until that is done. */ |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 260 | if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | pid = kernel_thread(wait_for_helper, sub_info, |
| 262 | CLONE_FS | CLONE_FILES | SIGCHLD); |
| 263 | else |
| 264 | pid = kernel_thread(____call_usermodehelper, sub_info, |
| 265 | CLONE_VFORK | SIGCHLD); |
| 266 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 267 | switch (wait) { |
| 268 | case UMH_NO_WAIT: |
| 269 | break; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 270 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 271 | case UMH_WAIT_PROC: |
| 272 | if (pid > 0) |
| 273 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | sub_info->retval = pid; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 275 | /* FALLTHROUGH */ |
| 276 | |
| 277 | case UMH_WAIT_EXEC: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | complete(sub_info->complete); |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 279 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | } |
| 281 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 282 | #ifdef CONFIG_PM_SLEEP |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 283 | /* |
| 284 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY |
| 285 | * (used for preventing user land processes from being created after the user |
| 286 | * land has been frozen during a system-wide hibernation or suspend operation). |
| 287 | */ |
| 288 | static int usermodehelper_disabled; |
| 289 | |
| 290 | /* Number of helpers running */ |
| 291 | static atomic_t running_helpers = ATOMIC_INIT(0); |
| 292 | |
| 293 | /* |
| 294 | * Wait queue head used by usermodehelper_pm_callback() to wait for all running |
| 295 | * helpers to finish. |
| 296 | */ |
| 297 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); |
| 298 | |
| 299 | /* |
| 300 | * Time to wait for running_helpers to become zero before the setting of |
| 301 | * usermodehelper_disabled in usermodehelper_pm_callback() fails |
| 302 | */ |
| 303 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) |
| 304 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 305 | /** |
| 306 | * usermodehelper_disable - prevent new helpers from being started |
| 307 | */ |
| 308 | int usermodehelper_disable(void) |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 309 | { |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 310 | long retval; |
| 311 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 312 | usermodehelper_disabled = 1; |
| 313 | smp_mb(); |
| 314 | /* |
| 315 | * From now on call_usermodehelper_exec() won't start any new |
| 316 | * helpers, so it is sufficient if running_helpers turns out to |
| 317 | * be zero at one point (it may be increased later, but that |
| 318 | * doesn't matter). |
| 319 | */ |
| 320 | retval = wait_event_timeout(running_helpers_waitq, |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 321 | atomic_read(&running_helpers) == 0, |
| 322 | RUNNING_HELPERS_TIMEOUT); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 323 | if (retval) |
| 324 | return 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 325 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 326 | usermodehelper_disabled = 0; |
| 327 | return -EAGAIN; |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * usermodehelper_enable - allow new helpers to be started again |
| 332 | */ |
| 333 | void usermodehelper_enable(void) |
| 334 | { |
| 335 | usermodehelper_disabled = 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 336 | } |
| 337 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 338 | static void helper_lock(void) |
| 339 | { |
| 340 | atomic_inc(&running_helpers); |
| 341 | smp_mb__after_atomic_inc(); |
| 342 | } |
| 343 | |
| 344 | static void helper_unlock(void) |
| 345 | { |
| 346 | if (atomic_dec_and_test(&running_helpers)) |
| 347 | wake_up(&running_helpers_waitq); |
| 348 | } |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 349 | #else /* CONFIG_PM_SLEEP */ |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 350 | #define usermodehelper_disabled 0 |
| 351 | |
| 352 | static inline void helper_lock(void) {} |
| 353 | static inline void helper_unlock(void) {} |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 354 | #endif /* CONFIG_PM_SLEEP */ |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 355 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 357 | * call_usermodehelper_setup - prepare to call a usermode helper |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 358 | * @path: path to usermode executable |
| 359 | * @argv: arg vector for process |
| 360 | * @envp: environment for process |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 361 | * @gfp_mask: gfp mask for memory allocation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | * |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 363 | * Returns either %NULL on allocation failure, or a subprocess_info |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 364 | * structure. This should be passed to call_usermodehelper_exec to |
| 365 | * exec the process and free the structure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 366 | */ |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 367 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
| 368 | char **envp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | { |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 370 | struct subprocess_info *sub_info; |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 371 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 372 | if (!sub_info) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 373 | goto out; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 374 | |
| 375 | INIT_WORK(&sub_info->work, __call_usermodehelper); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 376 | sub_info->path = path; |
| 377 | sub_info->argv = argv; |
| 378 | sub_info->envp = envp; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 379 | sub_info->cred = prepare_usermodehelper_creds(); |
Tetsuo Handa | ab2b7eb | 2009-05-26 09:11:03 +0100 | [diff] [blame] | 380 | if (!sub_info->cred) { |
| 381 | kfree(sub_info); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 382 | return NULL; |
Tetsuo Handa | ab2b7eb | 2009-05-26 09:11:03 +0100 | [diff] [blame] | 383 | } |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 384 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 385 | out: |
| 386 | return sub_info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | } |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 388 | EXPORT_SYMBOL(call_usermodehelper_setup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 390 | /** |
| 391 | * call_usermodehelper_setkeys - set the session keys for usermode helper |
| 392 | * @info: a subprocess_info returned by call_usermodehelper_setup |
| 393 | * @session_keyring: the session keyring for the process |
| 394 | */ |
| 395 | void call_usermodehelper_setkeys(struct subprocess_info *info, |
| 396 | struct key *session_keyring) |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 397 | { |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 398 | #ifdef CONFIG_KEYS |
| 399 | struct thread_group_cred *tgcred = info->cred->tgcred; |
| 400 | key_put(tgcred->session_keyring); |
| 401 | tgcred->session_keyring = key_get(session_keyring); |
| 402 | #else |
| 403 | BUG(); |
| 404 | #endif |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 405 | } |
| 406 | EXPORT_SYMBOL(call_usermodehelper_setkeys); |
| 407 | |
| 408 | /** |
| 409 | * call_usermodehelper_setcleanup - set a cleanup function |
| 410 | * @info: a subprocess_info returned by call_usermodehelper_setup |
| 411 | * @cleanup: a cleanup function |
| 412 | * |
| 413 | * The cleanup function is just befor ethe subprocess_info is about to |
| 414 | * be freed. This can be used for freeing the argv and envp. The |
| 415 | * Function must be runnable in either a process context or the |
| 416 | * context in which call_usermodehelper_exec is called. |
| 417 | */ |
| 418 | void call_usermodehelper_setcleanup(struct subprocess_info *info, |
| 419 | void (*cleanup)(char **argv, char **envp)) |
| 420 | { |
| 421 | info->cleanup = cleanup; |
| 422 | } |
| 423 | EXPORT_SYMBOL(call_usermodehelper_setcleanup); |
| 424 | |
| 425 | /** |
| 426 | * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin |
| 427 | * @sub_info: a subprocess_info returned by call_usermodehelper_setup |
| 428 | * @filp: set to the write-end of a pipe |
| 429 | * |
| 430 | * This constructs a pipe, and sets the read end to be the stdin of the |
| 431 | * subprocess, and returns the write-end in *@filp. |
| 432 | */ |
| 433 | int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, |
| 434 | struct file **filp) |
| 435 | { |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 436 | struct file *f; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 437 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 438 | f = create_write_pipe(0); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 439 | if (IS_ERR(f)) |
| 440 | return PTR_ERR(f); |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 441 | *filp = f; |
| 442 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 443 | f = create_read_pipe(f, 0); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 444 | if (IS_ERR(f)) { |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 445 | free_write_pipe(*filp); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 446 | return PTR_ERR(f); |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 447 | } |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 448 | sub_info->stdin = f; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 449 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 450 | return 0; |
| 451 | } |
| 452 | EXPORT_SYMBOL(call_usermodehelper_stdinpipe); |
| 453 | |
| 454 | /** |
| 455 | * call_usermodehelper_exec - start a usermode application |
| 456 | * @sub_info: information about the subprocessa |
| 457 | * @wait: wait for the application to finish and return status. |
| 458 | * when -1 don't wait at all, but you get no useful error back when |
| 459 | * the program couldn't be exec'ed. This makes it safe to call |
| 460 | * from interrupt context. |
| 461 | * |
| 462 | * Runs a user-space application. The application is started |
| 463 | * asynchronously if wait is not set, and runs as a child of keventd. |
| 464 | * (ie. it runs with full root capabilities). |
| 465 | */ |
| 466 | int call_usermodehelper_exec(struct subprocess_info *sub_info, |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 467 | enum umh_wait wait) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 468 | { |
| 469 | DECLARE_COMPLETION_ONSTACK(done); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 470 | int retval = 0; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 471 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 472 | BUG_ON(atomic_read(&sub_info->cred->usage) != 1); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 473 | validate_creds(sub_info->cred); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 474 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 475 | helper_lock(); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 476 | if (sub_info->path[0] == '\0') |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 477 | goto out; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 478 | |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 479 | if (!khelper_wq || usermodehelper_disabled) { |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 480 | retval = -EBUSY; |
| 481 | goto out; |
| 482 | } |
| 483 | |
| 484 | sub_info->complete = &done; |
| 485 | sub_info->wait = wait; |
| 486 | |
| 487 | queue_work(khelper_wq, &sub_info->work); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 488 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
| 489 | goto unlock; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 490 | wait_for_completion(&done); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 491 | retval = sub_info->retval; |
| 492 | |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 493 | out: |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 494 | call_usermodehelper_freeinfo(sub_info); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 495 | unlock: |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 496 | helper_unlock(); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 497 | return retval; |
| 498 | } |
| 499 | EXPORT_SYMBOL(call_usermodehelper_exec); |
| 500 | |
| 501 | /** |
| 502 | * call_usermodehelper_pipe - call a usermode helper process with a pipe stdin |
| 503 | * @path: path to usermode executable |
| 504 | * @argv: arg vector for process |
| 505 | * @envp: environment for process |
| 506 | * @filp: set to the write-end of a pipe |
| 507 | * |
| 508 | * This is a simple wrapper which executes a usermode-helper function |
| 509 | * with a pipe as stdin. It is implemented entirely in terms of |
| 510 | * lower-level call_usermodehelper_* functions. |
| 511 | */ |
| 512 | int call_usermodehelper_pipe(char *path, char **argv, char **envp, |
| 513 | struct file **filp) |
| 514 | { |
| 515 | struct subprocess_info *sub_info; |
| 516 | int ret; |
| 517 | |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 518 | sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 519 | if (sub_info == NULL) |
| 520 | return -ENOMEM; |
| 521 | |
| 522 | ret = call_usermodehelper_stdinpipe(sub_info, filp); |
| 523 | if (ret < 0) |
| 524 | goto out; |
| 525 | |
Michael Ellerman | 3210f0e | 2007-09-11 15:23:51 -0700 | [diff] [blame] | 526 | return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 527 | |
| 528 | out: |
| 529 | call_usermodehelper_freeinfo(sub_info); |
| 530 | return ret; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 531 | } |
| 532 | EXPORT_SYMBOL(call_usermodehelper_pipe); |
| 533 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 534 | void __init usermodehelper_init(void) |
| 535 | { |
| 536 | khelper_wq = create_singlethread_workqueue("khelper"); |
| 537 | BUG_ON(!khelper_wq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | } |