udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static int debug_trace;
  49 static int verbose;
  50
  51 static struct udev_rules rules;
  52 static int udevd_sock = -1;
  53 static int uevent_netlink_sock = -1;
  54 static int inotify_fd = -1;
  55 static pid_t sid;
  56
  57 static int signal_pipe[2] = {-1, -1};
  58 static volatile int sigchilds_waiting;
  59 static volatile int udev_exit;
  60 static volatile int reload_config;
  61 static int run_exec_q;
  62 static int stop_exec_q;
  63 static int max_childs;
  64 static int max_childs_running;
  65 static char udev_log[32];
  66
  67 static LIST_HEAD(exec_list);
  68 static LIST_HEAD(running_list);
  69
  70
  71 #ifdef USE_LOG
  72 void log_message(int priority, const char *format, ...)
  73 {
  74         va_list args;
  75
  76         if (priority > udev_log_priority)
  77                 return;
  78
  79         va_start(args, format);
  80         if (verbose) {
  81                 printf("[%d] ", (int) getpid());
  82                 vprintf(format, args);
  83                 printf("\n");
  84         } else
  85                 vsyslog(priority, format, args);
  86         va_end(args);
  87 }
  88
  89 #endif
  90
  91 static void asmlinkage udev_event_sig_handler(int signum)
  92 {
  93         if (signum == SIGALRM)
  94                 exit(1);
  95 }
  96
  97 static int udev_event_process(struct udevd_uevent_msg *msg)
  98 {
  99         struct sigaction act;
 100         struct udevice *udev;
 101         int i;
 102         int retval;
 103
 104         /* set signal handlers */
 105         memset(&act, 0x00, sizeof(act));
 106         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 107         sigemptyset (&act.sa_mask);
 108         act.sa_flags = 0;
 109         sigaction(SIGALRM, &act, NULL);
 110
 111         /* reset to default */
 112         act.sa_handler = SIG_DFL;
 113         sigaction(SIGINT, &act, NULL);
 114         sigaction(SIGTERM, &act, NULL);
 115         sigaction(SIGCHLD, &act, NULL);
 116         sigaction(SIGHUP, &act, NULL);
 117
 118         /* trigger timeout to prevent hanging processes */
 119         alarm(UDEV_ALARM_TIMEOUT);
 120
 121         /* reconstruct event environment from message */
 122         for (i = 0; msg->envp[i]; i++)
 123                 putenv(msg->envp[i]);
 124
 125         udev = udev_device_init(NULL);
 126         if (udev == NULL)
 127                 return -1;
 128         strlcpy(udev->action, msg->action, sizeof(udev->action));
 129         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 130         udev->devpath_old = msg->devpath_old;
 131         udev->devt = msg->devt;
 132
 133         retval = udev_device_event(&rules, udev);
 134
 135         /* run programs collected by RUN-key*/
 136         if (retval == 0 && !udev->ignore_device && udev_run)
 137                 retval = udev_rules_run(udev);
 138
 139         udev_device_cleanup(udev);
 140         return retval;
 141 }
 142
 143 enum event_state {
 144         EVENT_QUEUED,
 145         EVENT_FINISHED,
 146         EVENT_FAILED,
 147 };
 148
 149 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 150 {
 151         char filename[PATH_SIZE];
 152         char filename_failed[PATH_SIZE];
 153         size_t start;
 154
 155         /* location of queue file */
 156         snprintf(filename, sizeof(filename), "%s/"EVENT_QUEUE_DIR"/%llu", udev_root, msg->seqnum);
 157
 158         /* location of failed file */
 159         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 160         strlcat(filename_failed, "/", sizeof(filename_failed));
 161         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 162         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 163         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 164
 165         switch (state) {
 166         case EVENT_QUEUED:
 167                 unlink(filename_failed);
 168                 delete_path(filename_failed);
 169
 170                 create_path(filename);
 171                 symlink(msg->devpath, filename);
 172                 break;
 173         case EVENT_FINISHED:
 174                 if (msg->devpath_old != NULL) {
 175                         /* "move" event - rename failed file to current name, do not delete failed */
 176                         char filename_failed_old[PATH_SIZE];
 177
 178                         strlcpy(filename_failed_old, udev_root, sizeof(filename_failed_old));
 179                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 180                         start = strlcat(filename_failed_old, EVENT_FAILED_DIR"/", sizeof(filename_failed_old));
 181                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 182                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 183
 184                         if (rename(filename_failed_old, filename_failed) == 0)
 185                                 info("renamed devpath, moved failed state of '%s' to %s'",
 186                                      msg->devpath_old, msg->devpath);
 187                 } else {
 188                         unlink(filename_failed);
 189                         delete_path(filename_failed);
 190                 }
 191
 192                 unlink(filename);
 193                 delete_path(filename);
 194                 break;
 195         case EVENT_FAILED:
 196                 /* move failed event to the failed directory */
 197                 create_path(filename_failed);
 198                 rename(filename, filename_failed);
 199
 200                 /* clean up possibly empty queue directory */
 201                 delete_path(filename);
 202                 break;
 203         }
 204
 205         return;
 206 }
 207
 208 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 209 {
 210         list_del(&msg->node);
 211
 212         /* mark as failed, if "add" event returns non-zero */
 213         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 214                 export_event_state(msg, EVENT_FAILED);
 215         else
 216                 export_event_state(msg, EVENT_FINISHED);
 217
 218         free(msg);
 219 }
 220
 221 static void udev_event_run(struct udevd_uevent_msg *msg)
 222 {
 223         pid_t pid;
 224         int retval;
 225
 226         pid = fork();
 227         switch (pid) {
 228         case 0:
 229                 /* child */
 230                 close(uevent_netlink_sock);
 231                 close(udevd_sock);
 232                 if (inotify_fd >= 0)
 233                         close(inotify_fd);
 234                 close(signal_pipe[READ_END]);
 235                 close(signal_pipe[WRITE_END]);
 236                 logging_close();
 237
 238                 logging_init("udevd-event");
 239                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 240
 241                 retval = udev_event_process(msg);
 242                 info("seq %llu finished with %i", msg->seqnum, retval);
 243
 244                 logging_close();
 245                 if (retval)
 246                         exit(1);
 247                 exit(0);
 248         case -1:
 249                 err("fork of child failed: %s", strerror(errno));
 250                 msg_queue_delete(msg);
 251                 break;
 252         default:
 253                 /* get SIGCHLD in main loop */
 254                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 255                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 256                 msg->pid = pid;
 257         }
 258 }
 259
 260 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 261 {
 262         char filename[PATH_SIZE];
 263         int fd;
 264
 265         msg->queue_time = time(NULL);
 266
 267         strlcpy(filename, udev_root, sizeof(filename));
 268         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 269         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 270         if (fd >= 0) {
 271                 char str[32];
 272                 int len;
 273
 274                 len = sprintf(str, "%llu\n", msg->seqnum);
 275                 write(fd, str, len);
 276                 close(fd);
 277         }
 278
 279         export_event_state(msg, EVENT_QUEUED);
 280         info("seq %llu queued, '%s' '%s'", msg->seqnum, msg->action, msg->subsystem);
 281
 282         /* run one event after the other in debug mode */
 283         if (debug_trace) {
 284                 list_add_tail(&msg->node, &running_list);
 285                 udev_event_run(msg);
 286                 waitpid(msg->pid, NULL, 0);
 287                 msg_queue_delete(msg);
 288                 return;
 289         }
 290
 291         /* run all events with a timeout set immediately */
 292         if (msg->timeout != 0) {
 293                 list_add_tail(&msg->node, &running_list);
 294                 udev_event_run(msg);
 295                 return;
 296         }
 297
 298         list_add_tail(&msg->node, &exec_list);
 299         run_exec_q = 1;
 300 }
 301
 302 static int mem_size_mb(void)
 303 {
 304         FILE* f;
 305         char buf[4096];
 306         long int memsize = -1;
 307
 308         f = fopen("/proc/meminfo", "r");
 309         if (f == NULL)
 310                 return -1;
 311
 312         while (fgets(buf, sizeof(buf), f) != NULL) {
 313                 long int value;
 314
 315                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 316                         memsize = value / 1024;
 317                         break;
 318                 }
 319         }
 320
 321         fclose(f);
 322         return memsize;
 323 }
 324
 325 static int cpu_count(void)
 326 {
 327         FILE* f;
 328         char buf[4096];
 329         int count = 0;
 330
 331         f = fopen("/proc/stat", "r");
 332         if (f == NULL)
 333                 return -1;
 334
 335         while (fgets(buf, sizeof(buf), f) != NULL) {
 336                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 337                         count++;
 338         }
 339
 340         fclose(f);
 341         if (count == 0)
 342                 return -1;
 343         return count;
 344 }
 345
 346 static int running_processes(void)
 347 {
 348         FILE* f;
 349         char buf[4096];
 350         int running = -1;
 351
 352         f = fopen("/proc/stat", "r");
 353         if (f == NULL)
 354                 return -1;
 355
 356         while (fgets(buf, sizeof(buf), f) != NULL) {
 357                 int value;
 358
 359                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 360                         running = value;
 361                         break;
 362                 }
 363         }
 364
 365         fclose(f);
 366         return running;
 367 }
 368
 369 /* return the number of process es in our session, count only until limit */
 370 static int running_processes_in_session(pid_t session, int limit)
 371 {
 372         DIR *dir;
 373         struct dirent *dent;
 374         int running = 0;
 375
 376         dir = opendir("/proc");
 377         if (!dir)
 378                 return -1;
 379
 380         /* read process info from /proc */
 381         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 382                 int f;
 383                 char procdir[64];
 384                 char line[256];
 385                 const char *pos;
 386                 char state;
 387                 pid_t ppid, pgrp, sess;
 388                 int len;
 389
 390                 if (!isdigit(dent->d_name[0]))
 391                         continue;
 392
 393                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 394                 procdir[sizeof(procdir)-1] = '\0';
 395
 396                 f = open(procdir, O_RDONLY);
 397                 if (f == -1)
 398                         continue;
 399
 400                 len = read(f, line, sizeof(line)-1);
 401                 close(f);
 402
 403                 if (len <= 0)
 404                         continue;
 405                 else
 406                         line[len] = '\0';
 407
 408                 /* skip ugly program name */
 409                 pos = strrchr(line, ')') + 2;
 410                 if (pos == NULL)
 411                         continue;
 412
 413                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 414                         continue;
 415
 416                 /* count only processes in our session */
 417                 if (sess != session)
 418                         continue;
 419
 420                 /* count only running, no sleeping processes */
 421                 if (state != 'R')
 422                         continue;
 423
 424                 running++;
 425                 if (limit > 0 && running >= limit)
 426                         break;
 427         }
 428         closedir(dir);
 429
 430         return running;
 431 }
 432
 433 static int compare_devpath(const char *running, const char *waiting)
 434 {
 435         int i;
 436
 437         for (i = 0; i < PATH_SIZE; i++) {
 438                 /* identical device event found */
 439                 if (running[i] == '\0' && waiting[i] == '\0')
 440                         return 1;
 441
 442                 /* parent device event found */
 443                 if (running[i] == '\0' && waiting[i] == '/')
 444                         return 2;
 445
 446                 /* child device event found */
 447                 if (running[i] == '/' && waiting[i] == '\0')
 448                         return 3;
 449
 450                 /* no matching event */
 451                 if (running[i] != waiting[i])
 452                         break;
 453         }
 454
 455         return 0;
 456 }
 457
 458 /* lookup event for identical, parent, child, or physical device */
 459 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 460 {
 461         struct udevd_uevent_msg *loop_msg;
 462         int childs_count = 0;
 463
 464         /* check exec-queue which may still contain delayed events we depend on */
 465         list_for_each_entry(loop_msg, &exec_list, node) {
 466                 /* skip ourself and all later events */
 467                 if (loop_msg->seqnum >= msg->seqnum)
 468                         break;
 469
 470                 /* check our old name */
 471                 if (msg->devpath_old != NULL)
 472                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 473                                 return 2;
 474
 475                 /* check identical, parent, or child device event */
 476                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 477                         dbg("%llu, device event still pending %llu (%s)",
 478                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 479                         return 3;
 480                 }
 481
 482                 /* check for our major:minor number */
 483                 if (msg->devt && loop_msg->devt == msg->devt &&
 484                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 485                         dbg("%llu, device event still pending %llu (%d:%d)", msg->seqnum,
 486                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 487                         return 4;
 488                 }
 489
 490                 /* check physical device event (special case of parent) */
 491                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 492                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 493                                 dbg("%llu, physical device event still pending %llu (%s)",
 494                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 495                                 return 5;
 496                         }
 497         }
 498
 499         /* check run queue for still running events */
 500         list_for_each_entry(loop_msg, &running_list, node) {
 501                 if (limit && childs_count++ > limit) {
 502                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 503                         return 1;
 504                 }
 505
 506                 /* check our old name */
 507                 if (msg->devpath_old != NULL)
 508                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 509                                 return 2;
 510
 511                 /* check identical, parent, or child device event */
 512                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 513                         dbg("%llu, device event still running %llu (%s)",
 514                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 515                         return 3;
 516                 }
 517
 518                 /* check for our major:minor number */
 519                 if (msg->devt && loop_msg->devt == msg->devt &&
 520                     strcmp(msg->subsystem, loop_msg->subsystem) == 0) {
 521                         dbg("%llu, device event still running %llu (%d:%d)", msg->seqnum,
 522                             loop_msg->seqnum, major(loop_msg->devt), minor(loop_msg->devt));
 523                         return 4;
 524                 }
 525
 526                 /* check physical device event (special case of parent) */
 527                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 528                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 529                                 dbg("%llu, physical device event still running %llu (%s)",
 530                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 531                                 return 5;
 532                         }
 533         }
 534         return 0;
 535 }
 536
 537 /* serializes events for the identical and parent and child devices */
 538 static void msg_queue_manager(void)
 539 {
 540         struct udevd_uevent_msg *loop_msg;
 541         struct udevd_uevent_msg *tmp_msg;
 542         int running;
 543
 544         if (list_empty(&exec_list))
 545                 return;
 546
 547         running = running_processes();
 548         dbg("%d processes runnning on system", running);
 549         if (running < 0)
 550                 running = max_childs_running;
 551
 552         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 553                 /* check running processes in our session and possibly throttle */
 554                 if (running >= max_childs_running) {
 555                         running = running_processes_in_session(sid, max_childs_running+10);
 556                         dbg("at least %d processes running in session", running);
 557                         if (running >= max_childs_running) {
 558                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 559                                 return;
 560                         }
 561                 }
 562
 563                 /* serialize and wait for parent or child events */
 564                 if (devpath_busy(loop_msg, max_childs) != 0) {
 565                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 566                         continue;
 567                 }
 568
 569                 /* move event to run list */
 570                 list_move_tail(&loop_msg->node, &running_list);
 571                 udev_event_run(loop_msg);
 572                 running++;
 573                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 574         }
 575 }
 576
 577 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 578 {
 579         int bufpos;
 580         int i;
 581         struct udevd_uevent_msg *msg;
 582         char *physdevdriver_key = NULL;
 583         int maj = 0;
 584         int min = 0;
 585
 586         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 587         if (msg == NULL)
 588                 return NULL;
 589         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 590
 591         /* copy environment buffer and reconstruct envp */
 592         memcpy(msg->envbuf, buf, buf_size);
 593         bufpos = 0;
 594         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 595                 int keylen;
 596                 char *key;
 597
 598                 key = &msg->envbuf[bufpos];
 599                 keylen = strlen(key);
 600                 msg->envp[i] = key;
 601                 bufpos += keylen + 1;
 602                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 603
 604                 /* remember some keys for further processing */
 605                 if (strncmp(key, "ACTION=", 7) == 0)
 606                         msg->action = &key[7];
 607                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 608                         msg->devpath = &key[8];
 609                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 610                         msg->subsystem = &key[10];
 611                 else if (strncmp(key, "DRIVER=", 7) == 0)
 612                         msg->driver = &key[7];
 613                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 614                         msg->seqnum = strtoull(&key[7], NULL, 10);
 615                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 616                         msg->devpath_old = &key[12];
 617                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 618                         msg->physdevpath = &key[12];
 619                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 620                         physdevdriver_key = key;
 621                 else if (strncmp(key, "MAJOR=", 6) == 0)
 622                         maj = strtoull(&key[6], NULL, 10);
 623                 else if (strncmp(key, "MINOR=", 6) == 0)
 624                         min = strtoull(&key[6], NULL, 10);
 625                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 626                         msg->timeout = strtoull(&key[8], NULL, 10);
 627         }
 628         msg->devt = makedev(maj, min);
 629         msg->envp[i++] = "UDEVD_EVENT=1";
 630
 631         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 632                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 633                 msg->envp[i++] = &physdevdriver_key[7];
 634                 msg->driver = &physdevdriver_key[14];
 635         }
 636
 637         msg->envp[i] = NULL;
 638
 639         if (msg->devpath == NULL || msg->action == NULL) {
 640                 info("DEVPATH or ACTION missing, ignore message");
 641                 free(msg);
 642                 return NULL;
 643         }
 644         return msg;
 645 }
 646
 647 /* receive the udevd message from userspace */
 648 static void get_ctrl_msg(void)
 649 {
 650         struct udevd_ctrl_msg ctrl_msg;
 651         ssize_t size;
 652         struct msghdr smsg;
 653         struct cmsghdr *cmsg;
 654         struct iovec iov;
 655         struct ucred *cred;
 656         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 657         int *intval;
 658         char *pos;
 659
 660         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 661         iov.iov_base = &ctrl_msg;
 662         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 663
 664         memset(&smsg, 0x00, sizeof(struct msghdr));
 665         smsg.msg_iov = &iov;
 666         smsg.msg_iovlen = 1;
 667         smsg.msg_control = cred_msg;
 668         smsg.msg_controllen = sizeof(cred_msg);
 669
 670         size = recvmsg(udevd_sock, &smsg, 0);
 671         if (size <  0) {
 672                 if (errno != EINTR)
 673                         err("unable to receive user udevd message: %s", strerror(errno));
 674                 return;
 675         }
 676         cmsg = CMSG_FIRSTHDR(&smsg);
 677         cred = (struct ucred *) CMSG_DATA(cmsg);
 678
 679         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 680                 err("no sender credentials received, message ignored");
 681                 return;
 682         }
 683
 684         if (cred->uid != 0) {
 685                 err("sender uid=%i, message ignored", cred->uid);
 686                 return;
 687         }
 688
 689         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 690                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 691                 return;
 692         }
 693
 694         switch (ctrl_msg.type) {
 695         case UDEVD_CTRL_ENV:
 696                 pos = strchr(ctrl_msg.buf, '=');
 697                 if (pos == NULL) {
 698                         err("wrong key format '%s'", ctrl_msg.buf);
 699                         break;
 700                 }
 701                 pos[0] = '\0';
 702                 if (pos[1] == '\0') {
 703                         info("udevd message (ENV) received, unset '%s'", ctrl_msg.buf);
 704                         unsetenv(ctrl_msg.buf);
 705                 } else {
 706                         info("udevd message (ENV) received, set '%s=%s'", ctrl_msg.buf, &pos[1]);
 707                         setenv(ctrl_msg.buf, &pos[1], 1);
 708                 }
 709                 break;
 710         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 711                 info("udevd message (STOP_EXEC_QUEUE) received");
 712                 stop_exec_q = 1;
 713                 break;
 714         case UDEVD_CTRL_START_EXEC_QUEUE:
 715                 info("udevd message (START_EXEC_QUEUE) received");
 716                 stop_exec_q = 0;
 717                 msg_queue_manager();
 718                 break;
 719         case UDEVD_CTRL_SET_LOG_LEVEL:
 720                 intval = (int *) ctrl_msg.buf;
 721                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 722                 udev_log_priority = *intval;
 723                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 724                 putenv(udev_log);
 725                 break;
 726         case UDEVD_CTRL_SET_MAX_CHILDS:
 727                 intval = (int *) ctrl_msg.buf;
 728                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 729                 max_childs = *intval;
 730                 break;
 731         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 732                 intval = (int *) ctrl_msg.buf;
 733                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 734                 max_childs_running = *intval;
 735                 break;
 736         case UDEVD_CTRL_RELOAD_RULES:
 737                 info("udevd message (RELOAD_RULES) received");
 738                 reload_config = 1;
 739                 break;
 740         default:
 741                 err("unknown control message type");
 742         }
 743 }
 744
 745 /* receive the kernel user event message and do some sanity checks */
 746 static struct udevd_uevent_msg *get_netlink_msg(void)
 747 {
 748         struct udevd_uevent_msg *msg;
 749         int bufpos;
 750         ssize_t size;
 751         static char buffer[UEVENT_BUFFER_SIZE+512];
 752         char *pos;
 753
 754         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 755         if (size <  0) {
 756                 if (errno != EINTR)
 757                         err("unable to receive kernel netlink message: %s", strerror(errno));
 758                 return NULL;
 759         }
 760
 761         if ((size_t)size > sizeof(buffer)-1)
 762                 size = sizeof(buffer)-1;
 763         buffer[size] = '\0';
 764         dbg("uevent_size=%zi", size);
 765
 766         /* start of event payload */
 767         bufpos = strlen(buffer)+1;
 768         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 769         if (msg == NULL)
 770                 return NULL;
 771
 772         /* validate message */
 773         pos = strchr(buffer, '@');
 774         if (pos == NULL) {
 775                 err("invalid uevent '%s'", buffer);
 776                 free(msg);
 777                 return NULL;
 778         }
 779         pos[0] = '\0';
 780
 781         if (msg->action == NULL) {
 782                 info("no ACTION in payload found, skip event '%s'", buffer);
 783                 free(msg);
 784                 return NULL;
 785         }
 786
 787         if (strcmp(msg->action, buffer) != 0) {
 788                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 789                 free(msg);
 790                 return NULL;
 791         }
 792
 793         return msg;
 794 }
 795
 796 static void asmlinkage sig_handler(int signum)
 797 {
 798         switch (signum) {
 799                 case SIGINT:
 800                 case SIGTERM:
 801                         udev_exit = 1;
 802                         break;
 803                 case SIGCHLD:
 804                         /* set flag, then write to pipe if needed */
 805                         sigchilds_waiting = 1;
 806                         break;
 807                 case SIGHUP:
 808                         reload_config = 1;
 809                         break;
 810         }
 811
 812         /* write to pipe, which will wakeup select() in our mainloop */
 813         write(signal_pipe[WRITE_END], "", 1);
 814 }
 815
 816 static void udev_done(int pid, int exitstatus)
 817 {
 818         /* find msg associated with pid and delete it */
 819         struct udevd_uevent_msg *msg;
 820
 821         list_for_each_entry(msg, &running_list, node) {
 822                 if (msg->pid == pid) {
 823                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 824                              exitstatus, time(NULL) - msg->queue_time);
 825                         msg->exitstatus = exitstatus;
 826                         msg_queue_delete(msg);
 827
 828                         /* there may be events waiting with the same devpath */
 829                         run_exec_q = 1;
 830                         return;
 831                 }
 832         }
 833 }
 834
 835 static void reap_sigchilds(void)
 836 {
 837         pid_t pid;
 838         int status;
 839
 840         while (1) {
 841                 pid = waitpid(-1, &status, WNOHANG);
 842                 if (pid <= 0)
 843                         break;
 844                 if (WIFEXITED(status))
 845                         status = WEXITSTATUS(status);
 846                 else if (WIFSIGNALED(status))
 847                         status = WTERMSIG(status) + 128;
 848                 else
 849                         status = 0;
 850                 udev_done(pid, status);
 851         }
 852 }
 853
 854 static int init_udevd_socket(void)
 855 {
 856         struct sockaddr_un saddr;
 857         socklen_t addrlen;
 858         const int feature_on = 1;
 859         int retval;
 860
 861         memset(&saddr, 0x00, sizeof(saddr));
 862         saddr.sun_family = AF_LOCAL;
 863         /* use abstract namespace for socket path */
 864         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 865         addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(&saddr.sun_path[1]);
 866
 867         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 868         if (udevd_sock == -1) {
 869                 err("error getting socket: %s", strerror(errno));
 870                 return -1;
 871         }
 872
 873         /* the bind takes care of ensuring only one copy running */
 874         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 875         if (retval < 0) {
 876                 err("bind failed: %s", strerror(errno));
 877                 close(udevd_sock);
 878                 udevd_sock = -1;
 879                 return -1;
 880         }
 881
 882         /* enable receiving of the sender credentials */
 883         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 884
 885         return 0;
 886 }
 887
 888 static int init_uevent_netlink_sock(void)
 889 {
 890         struct sockaddr_nl snl;
 891         const int buffersize = 16 * 1024 * 1024;
 892         int retval;
 893
 894         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 895         snl.nl_family = AF_NETLINK;
 896         snl.nl_pid = getpid();
 897         snl.nl_groups = 1;
 898
 899         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 900         if (uevent_netlink_sock == -1) {
 901                 err("error getting socket: %s", strerror(errno));
 902                 return -1;
 903         }
 904
 905         /* set receive buffersize */
 906         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 907
 908         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 909         if (retval < 0) {
 910                 err("bind failed: %s", strerror(errno));
 911                 close(uevent_netlink_sock);
 912                 uevent_netlink_sock = -1;
 913                 return -1;
 914         }
 915         return 0;
 916 }
 917
 918 static void export_initial_seqnum(void)
 919 {
 920         char filename[PATH_SIZE];
 921         int fd;
 922         char seqnum[32];
 923         ssize_t len = 0;
 924
 925         strlcpy(filename, sysfs_path, sizeof(filename));
 926         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 927         fd = open(filename, O_RDONLY);
 928         if (fd >= 0) {
 929                 len = read(fd, seqnum, sizeof(seqnum)-1);
 930                 close(fd);
 931         }
 932         if (len <= 0) {
 933                 strcpy(seqnum, "0\n");
 934                 len = 3;
 935         }
 936         strlcpy(filename, udev_root, sizeof(filename));
 937         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 938         create_path(filename);
 939         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 940         if (fd >= 0) {
 941                 write(fd, seqnum, len);
 942                 close(fd);
 943         }
 944 }
 945
 946 int main(int argc, char *argv[], char *envp[])
 947 {
 948         int retval;
 949         int fd;
 950         struct sigaction act;
 951         fd_set readfds;
 952         const char *value;
 953         int daemonize = 0;
 954         int option;
 955         static const struct option options[] = {
 956                 { "daemon", 0, NULL, 'd' },
 957                 { "debug-trace", 0, NULL, 't' },
 958                 { "verbose", 0, NULL, 'v' },
 959                 { "help", 0, NULL, 'h' },
 960                 { "version", 0, NULL, 'V' },
 961                 {}
 962         };
 963         int rc = 1;
 964         int maxfd;
 965
 966         logging_init("udevd");
 967         udev_config_init();
 968         selinux_init();
 969         dbg("version %s", UDEV_VERSION);
 970
 971         while (1) {
 972                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 973                 if (option == -1)
 974                         break;
 975
 976                 switch (option) {
 977                 case 'd':
 978                         daemonize = 1;
 979                         break;
 980                 case 't':
 981                         debug_trace = 1;
 982                         break;
 983                 case 'v':
 984                         verbose = 1;
 985                         if (udev_log_priority < LOG_INFO)
 986                                 udev_log_priority = LOG_INFO;
 987                         break;
 988                 case 'h':
 989                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 990                         goto exit;
 991                 case 'V':
 992                         printf("%s\n", UDEV_VERSION);
 993                         goto exit;
 994                 default:
 995                         goto exit;
 996                 }
 997         }
 998
 999         if (getuid() != 0) {
1000                 fprintf(stderr, "root privileges required\n");
1001                 err("root privileges required");
1002                 goto exit;
1003         }
1004
1005         /* make sure std{in,out,err} fd's are in a sane state */
1006         fd = open("/dev/null", O_RDWR);
1007         if (fd < 0) {
1008                 fprintf(stderr, "cannot open /dev/null\n");
1009                 err("cannot open /dev/null");
1010         }
1011         if (fd > STDIN_FILENO)
1012                 dup2(fd, STDIN_FILENO);
1013         if (write(STDOUT_FILENO, 0, 0) < 0)
1014                 dup2(fd, STDOUT_FILENO);
1015         if (write(STDERR_FILENO, 0, 0) < 0)
1016                 dup2(fd, STDERR_FILENO);
1017
1018         /* init sockets to receive events */
1019         if (init_udevd_socket() < 0) {
1020                 if (errno == EADDRINUSE) {
1021                         fprintf(stderr, "another udev daemon already running\n");
1022                         err("another udev daemon already running");
1023                         rc = 1;
1024                 } else {
1025                         fprintf(stderr, "error initializing udevd socket\n");
1026                         err("error initializing udevd socket");
1027                         rc = 2;
1028                 }
1029                 goto exit;
1030         }
1031
1032         if (init_uevent_netlink_sock() < 0) {
1033                 fprintf(stderr, "error initializing netlink socket\n");
1034                 err("error initializing netlink socket");
1035                 rc = 3;
1036                 goto exit;
1037         }
1038
1039         /* setup signal handler pipe */
1040         retval = pipe(signal_pipe);
1041         if (retval < 0) {
1042                 err("error getting pipes: %s", strerror(errno));
1043                 goto exit;
1044         }
1045
1046         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1047         if (retval < 0) {
1048                 err("error fcntl on read pipe: %s", strerror(errno));
1049                 goto exit;
1050         }
1051         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1052         if (retval < 0) {
1053                 err("error fcntl on read pipe: %s", strerror(errno));
1054                 goto exit;
1055         }
1056
1057         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1058         if (retval < 0) {
1059                 err("error fcntl on write pipe: %s", strerror(errno));
1060                 goto exit;
1061         }
1062         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1063         if (retval < 0) {
1064                 err("error fcntl on write pipe: %s", strerror(errno));
1065                 goto exit;
1066         }
1067
1068         /* parse the rules and keep them in memory */
1069         sysfs_init();
1070         udev_rules_init(&rules, 1);
1071
1072         export_initial_seqnum();
1073
1074         if (daemonize) {
1075                 pid_t pid;
1076
1077                 pid = fork();
1078                 switch (pid) {
1079                 case 0:
1080                         dbg("daemonized fork running");
1081                         break;
1082                 case -1:
1083                         err("fork of daemon failed: %s", strerror(errno));
1084                         rc = 4;
1085                         goto exit;
1086                 default:
1087                         dbg("child [%u] running, parent exits", pid);
1088                         rc = 0;
1089                         goto exit;
1090                 }
1091         }
1092
1093         /* redirect std{out,err} fd's */
1094         if (!verbose)
1095                 dup2(fd, STDOUT_FILENO);
1096         dup2(fd, STDERR_FILENO);
1097         if (fd > STDERR_FILENO)
1098                 close(fd);
1099
1100         /* set scheduling priority for the daemon */
1101         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1102
1103         chdir("/");
1104         umask(022);
1105
1106         /* become session leader */
1107         sid = setsid();
1108         dbg("our session is %d", sid);
1109
1110         /* OOM_DISABLE == -17 */
1111         fd = open("/proc/self/oom_adj", O_RDWR);
1112         if (fd < 0)
1113                 err("error disabling OOM: %s", strerror(errno));
1114         else {
1115                 write(fd, "-17", 3);
1116                 close(fd);
1117         }
1118
1119         fd = open("/dev/kmsg", O_WRONLY);
1120         if (fd > 0) {
1121                 const char *str = "<6>udevd version " UDEV_VERSION " started\n";
1122
1123                 write(fd, str, strlen(str));
1124                 close(fd);
1125         }
1126
1127         /* set signal handlers */
1128         memset(&act, 0x00, sizeof(struct sigaction));
1129         act.sa_handler = (void (*)(int)) sig_handler;
1130         sigemptyset(&act.sa_mask);
1131         act.sa_flags = SA_RESTART;
1132         sigaction(SIGINT, &act, NULL);
1133         sigaction(SIGTERM, &act, NULL);
1134         sigaction(SIGCHLD, &act, NULL);
1135         sigaction(SIGHUP, &act, NULL);
1136
1137         /* watch rules directory */
1138         inotify_fd = inotify_init();
1139         if (inotify_fd >= 0) {
1140                 char filename[PATH_MAX];
1141
1142                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1143
1144                 /* watch dynamic rules directory */
1145                 strlcpy(filename, udev_root, sizeof(filename));
1146                 strlcat(filename, "/"RULES_DYN_DIR, sizeof(filename));
1147                 inotify_add_watch(inotify_fd, filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1148         } else if (errno == ENOSYS)
1149                 err("the kernel does not support inotify, udevd can't monitor rules file changes");
1150         else
1151                 err("inotify_init failed: %s", strerror(errno));
1152
1153         /* maximum limit of forked childs */
1154         value = getenv("UDEVD_MAX_CHILDS");
1155         if (value)
1156                 max_childs = strtoul(value, NULL, 10);
1157         else {
1158                 int memsize = mem_size_mb();
1159                 if (memsize > 0)
1160                         max_childs = 128 + (memsize / 4);
1161                 else
1162                         max_childs = UDEVD_MAX_CHILDS;
1163         }
1164         info("initialize max_childs to %u", max_childs);
1165
1166         /* start to throttle forking if maximum number of _running_ childs is reached */
1167         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1168         if (value)
1169                 max_childs_running = strtoull(value, NULL, 10);
1170         else {
1171                 int cpus = cpu_count();
1172                 if (cpus > 0)
1173                         max_childs_running = 8 + (8 * cpus);
1174                 else
1175                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1176         }
1177         info("initialize max_childs_running to %u", max_childs_running);
1178
1179         /* clear environment for forked event processes */
1180         clearenv();
1181
1182         /* export log_priority , as called programs may want to follow that setting */
1183         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1184         putenv(udev_log);
1185         if (debug_trace)
1186                 putenv("DEBUG=1");
1187
1188         maxfd = udevd_sock;
1189         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1190         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1191         maxfd = UDEV_MAX(maxfd, inotify_fd);
1192
1193         while (!udev_exit) {
1194                 struct udevd_uevent_msg *msg;
1195                 int fdcount;
1196
1197                 FD_ZERO(&readfds);
1198                 FD_SET(signal_pipe[READ_END], &readfds);
1199                 FD_SET(udevd_sock, &readfds);
1200                 FD_SET(uevent_netlink_sock, &readfds);
1201                 if (inotify_fd >= 0)
1202                         FD_SET(inotify_fd, &readfds);
1203
1204                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1205                 if (fdcount < 0) {
1206                         if (errno != EINTR)
1207                                 err("error in select: %s", strerror(errno));
1208                         continue;
1209                 }
1210
1211                 /* get control message */
1212                 if (FD_ISSET(udevd_sock, &readfds))
1213                         get_ctrl_msg();
1214
1215                 /* get netlink message */
1216                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1217                         msg = get_netlink_msg();
1218                         if (msg)
1219                                 msg_queue_insert(msg);
1220                 }
1221
1222                 /* received a signal, clear our notification pipe */
1223                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1224                         char buf[256];
1225
1226                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1227                 }
1228
1229                 /* rules directory inotify watch */
1230                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1231                         int nbytes;
1232
1233                         /* discard all possible events, we can just reload the config */
1234                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1235                                 char *buf;
1236
1237                                 reload_config = 1;
1238                                 buf = malloc(nbytes);
1239                                 if (buf == NULL) {
1240                                         err("error getting buffer for inotify, disable watching");
1241                                         close(inotify_fd);
1242                                         inotify_fd = -1;
1243                                 }
1244                                 read(inotify_fd, buf, nbytes);
1245                                 free(buf);
1246                         }
1247                 }
1248
1249                 /* rules changed, set by inotify or a HUP signal */
1250                 if (reload_config) {
1251                         reload_config = 0;
1252                         udev_rules_cleanup(&rules);
1253                         udev_rules_init(&rules, 1);
1254                 }
1255
1256                 /* forked child has returned */
1257                 if (sigchilds_waiting) {
1258                         sigchilds_waiting = 0;
1259                         reap_sigchilds();
1260                 }
1261
1262                 if (run_exec_q) {
1263                         run_exec_q = 0;
1264                         if (!stop_exec_q)
1265                                 msg_queue_manager();
1266                 }
1267         }
1268         rc = 0;
1269
1270 exit:
1271         udev_rules_cleanup(&rules);
1272         sysfs_cleanup();
1273         selinux_exit();
1274
1275         if (signal_pipe[READ_END] >= 0)
1276                 close(signal_pipe[READ_END]);
1277         if (signal_pipe[WRITE_END] >= 0)
1278                 close(signal_pipe[WRITE_END]);
1279
1280         if (udevd_sock >= 0)
1281                 close(udevd_sock);
1282         if (inotify_fd >= 0)
1283                 close(inotify_fd);
1284         if (uevent_netlink_sock >= 0)
1285                 close(uevent_netlink_sock);
1286
1287         logging_close();
1288
1289         return rc;
1290 }