2 * libudev - interface to udev device information
4 * Copyright (C) 2003-2009 Kay Sievers <kay.sievers@vrfy.org>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
22 #include <sys/prctl.h>
23 #include <sys/epoll.h>
25 #include <sys/param.h>
28 #include "libudev-private.h"
30 static int create_path(struct udev *udev, const char *path, bool selinux)
32 char p[UTIL_PATH_SIZE];
37 util_strscpy(p, sizeof(p), path);
38 pos = strrchr(p, '/');
41 while (pos != p && pos[-1] == '/')
47 dbg(udev, "stat '%s'\n", p);
48 if (stat(p, &stats) == 0) {
49 if ((stats.st_mode & S_IFMT) == S_IFDIR)
55 err = util_create_path(udev, p);
59 dbg(udev, "mkdir '%s'\n", p);
61 udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
65 if (err == -EEXIST && stat(p, &stats) == 0) {
66 if ((stats.st_mode & S_IFMT) == S_IFDIR)
73 udev_selinux_resetfscreatecon(udev);
77 int util_create_path(struct udev *udev, const char *path)
79 return create_path(udev, path, false);
82 int util_create_path_selinux(struct udev *udev, const char *path)
84 return create_path(udev, path, true);
87 int util_delete_path(struct udev *udev, const char *path)
89 char p[UTIL_PATH_SIZE];
96 util_strscpy(p, sizeof(p), path);
97 pos = strrchr(p, '/');
98 if (pos == p || pos == NULL)
103 pos = strrchr(p, '/');
105 /* don't remove the last one */
106 if ((pos == p) || (pos == NULL))
119 /* Reset permissions on the device node, before unlinking it to make sure,
120 * that permissions of possible hard links will be removed too.
122 int util_unlink_secure(struct udev *udev, const char *filename)
126 chown(filename, 0, 0);
127 chmod(filename, 0000);
128 err = unlink(filename);
132 err(udev, "unlink(%s) failed: %m\n", filename);
136 uid_t util_lookup_user(struct udev *udev, const char *user)
139 size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
145 if (strcmp(user, "root") == 0)
147 uid = strtoul(user, &endptr, 10);
148 if (endptr[0] == '\0')
151 errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
154 if (errno == 0 || errno == ENOENT || errno == ESRCH)
155 err(udev, "specified user '%s' unknown\n", user);
157 err(udev, "error resolving user '%s': %m\n", user);
161 gid_t util_lookup_group(struct udev *udev, const char *group)
164 size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
170 if (strcmp(group, "root") == 0)
172 gid = strtoul(group, &endptr, 10);
173 if (endptr[0] == '\0')
180 newbuf = realloc(buf, buflen);
184 errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
187 } else if (errno == ERANGE) {
190 } else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
191 err(udev, "specified group '%s' unknown\n", group);
193 err(udev, "error resolving group '%s': %m\n", group);
201 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
202 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
203 char *result, size_t maxsize, int read_value)
205 char temp[UTIL_PATH_SIZE];
208 struct udev_device *dev;
211 if (string[0] != '[')
214 util_strscpy(temp, sizeof(temp), string);
218 sysname = strchr(subsys, '/');
222 sysname = &sysname[1];
224 attr = strchr(sysname, ']');
234 if (read_value && attr == NULL)
237 dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
244 val = udev_device_get_sysattr_value(dev, attr);
246 util_strscpy(result, maxsize, val);
249 info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
255 l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
257 util_strpcpyl(&s, l, "/", attr, NULL);
258 info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
260 udev_device_unref(dev);
264 static int run_program_exec(struct udev *udev, int fd_stdout, int fd_stderr,
265 char *const argv[], char **envp, const sigset_t *sigmask)
270 /* discard child output or connect to pipe */
271 fd = open("/dev/null", O_RDWR);
273 dup2(fd, STDIN_FILENO);
275 dup2(fd, STDOUT_FILENO);
277 dup2(fd, STDERR_FILENO);
280 err(udev, "open /dev/null failed: %m\n");
283 /* connect pipes to std{out,err} */
284 if (fd_stdout >= 0) {
285 dup2(fd_stdout, STDOUT_FILENO);
288 if (fd_stderr >= 0) {
289 dup2(fd_stderr, STDERR_FILENO);
293 /* terminate child in case parent goes away */
294 prctl(PR_SET_PDEATHSIG, SIGTERM);
296 /* restore original udev sigmask before exec */
298 sigprocmask(SIG_SETMASK, sigmask, NULL);
300 execve(argv[0], argv, envp);
304 if (err == -ENOENT || err == -ENOTDIR) {
305 /* may be on a filesystem which is not mounted right now */
306 info(udev, "program '%s' not found\n", argv[0]);
309 err(udev, "exec of program '%s' failed\n", argv[0]);
314 static int run_program_read(struct udev *udev, int fd_stdout, int fd_stderr,
315 char *const argv[], char *result, size_t ressize, size_t *reslen)
319 struct epoll_event ep_outpipe;
320 struct epoll_event ep_errpipe;
323 /* read from child if requested */
324 if (fd_stdout < 0 && fd_stderr < 0)
327 fd_ep = epoll_create1(EPOLL_CLOEXEC);
330 err(udev, "error creating epoll fd: %m\n");
334 if (fd_stdout >= 0) {
335 memset(&ep_outpipe, 0, sizeof(struct epoll_event));
336 ep_outpipe.events = EPOLLIN;
337 ep_outpipe.data.ptr = &fd_stdout;
338 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe) < 0) {
339 err(udev, "fail to add fd to epoll: %m\n");
344 if (fd_stderr >= 0) {
345 memset(&ep_errpipe, 0, sizeof(struct epoll_event));
346 ep_errpipe.events = EPOLLIN;
347 ep_errpipe.data.ptr = &fd_stderr;
348 if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe) < 0) {
349 err(udev, "fail to add fd to epoll: %m\n");
354 /* read child output */
355 while (fd_stdout >= 0 || fd_stderr >= 0) {
357 struct epoll_event ev[4];
360 fdcount = epoll_wait(fd_ep, ev, ARRAY_SIZE(ev), -1);
364 err(udev, "failed to poll: %m\n");
369 for (i = 0; i < fdcount; i++) {
370 int *fd = (int *)ev[i].data.ptr;
372 if (ev[i].events & EPOLLIN) {
376 count = read(*fd, buf, sizeof(buf)-1);
381 /* store stdout result */
382 if (result != NULL && *fd == fd_stdout) {
383 if (respos + count < ressize) {
384 memcpy(&result[respos], buf, count);
387 err(udev, "ressize %zd too short\n", ressize);
392 /* log debug output only if we watch stderr */
393 if (fd_stderr >= 0) {
398 while ((line = strsep(&pos, "\n"))) {
399 if (pos != NULL || line[0] != '\0')
400 info(udev, "'%s'(%s) '%s'\n", argv[0], *fd == fd_stdout ? "out" : "err" , line);
403 } else if (ev[i].events & EPOLLHUP) {
404 if (epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL) < 0) {
406 err(udev, "failed to remove fd from epoll: %m\n");
414 /* return the child's stdout string */
415 if (result != NULL) {
416 result[respos] = '\0';
417 dbg(udev, "result='%s'\n", result);
427 int util_run_program(struct udev *udev, const char *command, char **envp,
428 char *result, size_t ressize, size_t *reslen,
429 const sigset_t *sigmask)
432 int outpipe[2] = {-1, -1};
433 int errpipe[2] = {-1, -1};
435 char arg[UTIL_PATH_SIZE];
436 char program[UTIL_PATH_SIZE];
437 char *argv[((sizeof(arg) + 1) / 2) + 1];
441 info(udev, "'%s' started\n", command);
443 /* build argv from command */
444 util_strscpy(arg, sizeof(arg), command);
446 if (strchr(arg, ' ') != NULL) {
449 while (pos != NULL && pos[0] != '\0') {
450 if (pos[0] == '\'') {
451 /* do not separate quotes */
453 argv[i] = strsep(&pos, "\'");
455 while (pos[0] == ' ')
458 argv[i] = strsep(&pos, " ");
460 while (pos[0] == ' ')
463 dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
472 /* pipes from child to parent */
473 if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
474 if (pipe2(outpipe, O_NONBLOCK) != 0) {
476 err(udev, "pipe failed: %m\n");
480 if (udev_get_log_priority(udev) >= LOG_INFO) {
481 if (pipe2(errpipe, O_NONBLOCK) != 0) {
483 err(udev, "pipe failed: %m\n");
488 /* allow programs in /lib/udev/ to be called without the path */
489 if (argv[0][0] != '/') {
490 util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
497 /* child closes parent's ends of pipes */
498 if (outpipe[READ_END] >= 0) {
499 close(outpipe[READ_END]);
500 outpipe[READ_END] = -1;
502 if (errpipe[READ_END] >= 0) {
503 close(errpipe[READ_END]);
504 errpipe[READ_END] = -1;
507 err = run_program_exec(udev, outpipe[WRITE_END], errpipe[WRITE_END], argv, envp, sigmask);
511 err(udev, "fork of '%s' failed: %m\n", argv[0]);
515 /* parent closed child's ends of pipes */
516 if (outpipe[WRITE_END] >= 0) {
517 close(outpipe[WRITE_END]);
518 outpipe[WRITE_END] = -1;
520 if (errpipe[WRITE_END] >= 0) {
521 close(errpipe[WRITE_END]);
522 errpipe[WRITE_END] = -1;
525 err = run_program_read(udev, outpipe[READ_END], errpipe[READ_END], argv, result, ressize, reslen);
527 waitpid(pid, &status, 0);
528 if (WIFEXITED(status)) {
529 info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
530 if (WEXITSTATUS(status) != 0)
533 err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
539 if (outpipe[READ_END] >= 0)
540 close(outpipe[READ_END]);
541 if (outpipe[WRITE_END] >= 0)
542 close(outpipe[WRITE_END]);
543 if (errpipe[READ_END] >= 0)
544 close(errpipe[READ_END]);
545 if (errpipe[WRITE_END] >= 0)
546 close(errpipe[WRITE_END]);