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 <sys/select.h>
  33 #include <sys/wait.h>
  34 #include <sys/types.h>
  35 #include <sys/socket.h>
  36 #include <sys/un.h>
  37 #include <sys/stat.h>
  38 #include <sys/ioctl.h>
  39 #include <linux/types.h>
  40 #include <linux/netlink.h>
  41
  42 #include "udev.h"
  43 #include "udev_rules.h"
  44 #include "udevd.h"
  45 #include "udev_selinux.h"
  46
  47 static struct udev_rules rules;
  48 static int udevd_sock = -1;
  49 static int uevent_netlink_sock = -1;
  50 static int inotify_fd = -1;
  51 static pid_t sid;
  52
  53 static int signal_pipe[2] = {-1, -1};
  54 static volatile int sigchilds_waiting;
  55 static volatile int udev_exit;
  56 static volatile int reload_config;
  57 static int run_exec_q;
  58 static int stop_exec_q;
  59 static int max_childs;
  60 static int max_childs_running;
  61 static char udev_log[32];
  62
  63 static LIST_HEAD(exec_list);
  64 static LIST_HEAD(running_list);
  65
  66
  67 #ifdef USE_LOG
  68 void log_message(int priority, const char *format, ...)
  69 {
  70         va_list args;
  71
  72         if (priority > udev_log_priority)
  73                 return;
  74
  75         va_start(args, format);
  76         vsyslog(priority, format, args);
  77         va_end(args);
  78 }
  79 #endif
  80
  81 static void asmlinkage udev_event_sig_handler(int signum)
  82 {
  83         if (signum == SIGALRM)
  84                 exit(1);
  85 }
  86
  87 static int udev_event_process(struct udevd_uevent_msg *msg)
  88 {
  89         struct sigaction act;
  90         struct udevice *udev;
  91         int i;
  92         int retval;
  93
  94         /* set signal handlers */
  95         memset(&act, 0x00, sizeof(act));
  96         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  97         sigemptyset (&act.sa_mask);
  98         act.sa_flags = 0;
  99         sigaction(SIGALRM, &act, NULL);
 100
 101         /* reset to default */
 102         act.sa_handler = SIG_DFL;
 103         sigaction(SIGINT, &act, NULL);
 104         sigaction(SIGTERM, &act, NULL);
 105         sigaction(SIGCHLD, &act, NULL);
 106         sigaction(SIGHUP, &act, NULL);
 107
 108         /* trigger timeout to prevent hanging processes */
 109         alarm(UDEV_ALARM_TIMEOUT);
 110
 111         /* reconstruct event environment from message */
 112         for (i = 0; msg->envp[i]; i++)
 113                 putenv(msg->envp[i]);
 114
 115         udev = udev_device_init();
 116         if (udev == NULL)
 117                 return -1;
 118         strlcpy(udev->action, msg->action, sizeof(udev->action));
 119         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 120         udev->devt = msg->devt;
 121
 122         retval = udev_device_event(&rules, udev);
 123
 124         /* run programs collected by RUN-key*/
 125         if (retval == 0 && !udev->ignore_device && udev_run) {
 126                 struct name_entry *name_loop;
 127
 128                 dbg("executing run list");
 129                 list_for_each_entry(name_loop, &udev->run_list, node) {
 130                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 131                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 132                         else {
 133                                 char program[PATH_SIZE];
 134
 135                                 strlcpy(program, name_loop->name, sizeof(program));
 136                                 udev_rules_apply_format(udev, program, sizeof(program));
 137                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 138                                                 (udev_log_priority >= LOG_INFO)))
 139                                         retval = -1;
 140                         }
 141                 }
 142         }
 143
 144         udev_device_cleanup(udev);
 145         return retval;
 146 }
 147
 148 enum event_state {
 149         EVENT_QUEUED,
 150         EVENT_FINISHED,
 151         EVENT_FAILED,
 152 };
 153
 154 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 155 {
 156         char filename[PATH_SIZE];
 157         char filename_failed[PATH_SIZE];
 158         char target[PATH_SIZE];
 159         size_t start, end, i;
 160         struct udevd_uevent_msg *loop_msg;
 161
 162         /* add location of queue files */
 163         strlcpy(filename, udev_root, sizeof(filename));
 164         strlcat(filename, "/", sizeof(filename));
 165         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 166         end = strlcat(filename, msg->devpath, sizeof(filename));
 167         if (end > sizeof(filename))
 168                 end = sizeof(filename);
 169
 170         /* replace '/' to transform path into a filename */
 171         for (i = start+1; i < end; i++)
 172                 if (filename[i] == '/')
 173                         filename[i] = PATH_TO_NAME_CHAR;
 174
 175         /* add location of failed files */
 176         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 177         strlcat(filename_failed, "/", sizeof(filename_failed));
 178         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 179         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 180         if (end > sizeof(filename_failed))
 181                 end = sizeof(filename_failed);
 182
 183         /* replace '/' to transform path into a filename */
 184         for (i = start+1; i < end; i++)
 185                 if (filename_failed[i] == '/')
 186                         filename_failed[i] = PATH_TO_NAME_CHAR;
 187
 188         switch (state) {
 189         case EVENT_QUEUED:
 190                 unlink(filename_failed);
 191                 delete_path(filename_failed);
 192
 193                 strlcpy(target, sysfs_path, sizeof(target));
 194                 strlcat(target, msg->devpath, sizeof(target));
 195                 create_path(filename);
 196                 symlink(target, filename);
 197                 return;
 198         case EVENT_FINISHED:
 199         case EVENT_FAILED:
 200                 unlink(filename_failed);
 201                 delete_path(filename_failed);
 202
 203                 /* don't remove, if events for the same path are still pending */
 204                 list_for_each_entry(loop_msg, &running_list, node)
 205                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 206                                 return;
 207
 208                 list_for_each_entry(loop_msg, &exec_list, node)
 209                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 210                                 return;
 211
 212                 /* move failed events to the failed directory */
 213                 if (state == EVENT_FAILED) {
 214                         create_path(filename_failed);
 215                         rename(filename, filename_failed);
 216                 } else {
 217                         unlink(filename);
 218                 }
 219
 220                 /* clean up the queue directory */
 221                 delete_path(filename);
 222
 223                 return;
 224         }
 225 }
 226
 227 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 228 {
 229         list_del(&msg->node);
 230
 231         /* mark as failed, if add event returns non-zero */
 232         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 233                 export_event_state(msg, EVENT_FAILED);
 234         else
 235                 export_event_state(msg, EVENT_FINISHED);
 236
 237         free(msg);
 238 }
 239
 240 static void udev_event_run(struct udevd_uevent_msg *msg)
 241 {
 242         pid_t pid;
 243         int retval;
 244
 245         pid = fork();
 246         switch (pid) {
 247         case 0:
 248                 /* child */
 249                 close(uevent_netlink_sock);
 250                 close(udevd_sock);
 251                 if (inotify_fd >= 0)
 252                         close(inotify_fd);
 253                 close(signal_pipe[READ_END]);
 254                 close(signal_pipe[WRITE_END]);
 255                 logging_close();
 256
 257                 logging_init("udevd-event");
 258                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 259
 260                 retval = udev_event_process(msg);
 261                 info("seq %llu finished", msg->seqnum);
 262
 263                 logging_close();
 264                 if (retval)
 265                         exit(1);
 266                 exit(0);
 267         case -1:
 268                 err("fork of child failed: %s", strerror(errno));
 269                 msg_queue_delete(msg);
 270                 break;
 271         default:
 272                 /* get SIGCHLD in main loop */
 273                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 274                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 275                 msg->pid = pid;
 276         }
 277 }
 278
 279 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 280 {
 281         char filename[PATH_SIZE];
 282         int fd;
 283
 284         msg->queue_time = time(NULL);
 285
 286         strlcpy(filename, udev_root, sizeof(filename));
 287         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 288         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 289         if (fd >= 0) {
 290                 char str[32];
 291                 int len;
 292
 293                 len = sprintf(str, "%llu\n", msg->seqnum);
 294                 write(fd, str, len);
 295                 close(fd);
 296         }
 297
 298         export_event_state(msg, EVENT_QUEUED);
 299
 300         /* run all events with a timeout set immediately */
 301         if (msg->timeout != 0) {
 302                 list_add_tail(&msg->node, &running_list);
 303                 udev_event_run(msg);
 304                 return;
 305         }
 306
 307         list_add_tail(&msg->node, &exec_list);
 308         run_exec_q = 1;
 309 }
 310
 311 static int mem_size_mb(void)
 312 {
 313         int f;
 314         char buf[8192];
 315         long int len;
 316         const char *pos;
 317         long int memsize;
 318
 319         f = open("/proc/meminfo", O_RDONLY);
 320         if (f == -1)
 321                 return -1;
 322
 323         len = read(f, buf, sizeof(buf)-1);
 324         close(f);
 325
 326         if (len <= 0)
 327                 return -1;
 328         buf[len] = '\0';
 329
 330         pos = strstr(buf, "MemTotal: ");
 331         if (pos == NULL)
 332                 return -1;
 333
 334         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 335                 return -1;
 336
 337         return memsize / 1024;
 338 }
 339
 340 static int cpu_count(void)
 341 {
 342         int f;
 343         char buf[32768];
 344         int len;
 345         const char *pos;
 346         int count = 0;
 347
 348         f = open("/proc/stat", O_RDONLY);
 349         if (f == -1)
 350                 return -1;
 351
 352         len = read(f, buf, sizeof(buf)-1);
 353         close(f);
 354         if (len <= 0)
 355                 return -1;
 356         buf[len] = '\0';
 357
 358         pos = strstr(buf, "cpu");
 359         if (pos == NULL)
 360                 return -1;
 361
 362         while (pos != NULL) {
 363                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 364                         count++;
 365                 pos = strstr(&pos[3], "cpu");
 366         }
 367
 368         if (count == 0)
 369                 return -1;
 370         return count;
 371 }
 372
 373 static int running_processes(void)
 374 {
 375         int f;
 376         char buf[32768];
 377         int len;
 378         int running;
 379         const char *pos;
 380
 381         f = open("/proc/stat", O_RDONLY);
 382         if (f == -1)
 383                 return -1;
 384
 385         len = read(f, buf, sizeof(buf)-1);
 386         close(f);
 387         if (len <= 0)
 388                 return -1;
 389         buf[len] = '\0';
 390
 391         pos = strstr(buf, "procs_running ");
 392         if (pos == NULL)
 393                 return -1;
 394
 395         if (sscanf(pos, "procs_running %u", &running) != 1)
 396                 return -1;
 397
 398         return running;
 399 }
 400
 401 /* return the number of process es in our session, count only until limit */
 402 static int running_processes_in_session(pid_t session, int limit)
 403 {
 404         DIR *dir;
 405         struct dirent *dent;
 406         int running = 0;
 407
 408         dir = opendir("/proc");
 409         if (!dir)
 410                 return -1;
 411
 412         /* read process info from /proc */
 413         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 414                 int f;
 415                 char procdir[64];
 416                 char line[256];
 417                 const char *pos;
 418                 char state;
 419                 pid_t ppid, pgrp, sess;
 420                 int len;
 421
 422                 if (!isdigit(dent->d_name[0]))
 423                         continue;
 424
 425                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 426                 procdir[sizeof(procdir)-1] = '\0';
 427
 428                 f = open(procdir, O_RDONLY);
 429                 if (f == -1)
 430                         continue;
 431
 432                 len = read(f, line, sizeof(line)-1);
 433                 close(f);
 434
 435                 if (len <= 0)
 436                         continue;
 437                 else
 438                         line[len] = '\0';
 439
 440                 /* skip ugly program name */
 441                 pos = strrchr(line, ')') + 2;
 442                 if (pos == NULL)
 443                         continue;
 444
 445                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 446                         continue;
 447
 448                 /* count only processes in our session */
 449                 if (sess != session)
 450                         continue;
 451
 452                 /* count only running, no sleeping processes */
 453                 if (state != 'R')
 454                         continue;
 455
 456                 running++;
 457                 if (limit > 0 && running >= limit)
 458                         break;
 459         }
 460         closedir(dir);
 461
 462         return running;
 463 }
 464
 465 static int compare_devpath(const char *running, const char *waiting)
 466 {
 467         int i;
 468
 469         for (i = 0; i < PATH_SIZE; i++) {
 470                 /* identical device event found */
 471                 if (running[i] == '\0' && waiting[i] == '\0')
 472                         return 1;
 473
 474                 /* parent device event found */
 475                 if (running[i] == '\0' && waiting[i] == '/')
 476                         return 2;
 477
 478                 /* child device event found */
 479                 if (running[i] == '/' && waiting[i] == '\0')
 480                         return 3;
 481
 482                 /* no matching event */
 483                 if (running[i] != waiting[i])
 484                         break;
 485         }
 486
 487         return 0;
 488 }
 489
 490 /* returns still running task for the same device, its parent or its physical device */
 491 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 492 {
 493         struct udevd_uevent_msg *loop_msg;
 494         int childs_count = 0;
 495
 496         list_for_each_entry(loop_msg, &running_list, node) {
 497                 if (limit && childs_count++ > limit) {
 498                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 499                         return 1;
 500                 }
 501
 502                 /* return running parent/child device event */
 503                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 504                         dbg("%llu, child device event still running %llu (%s)",
 505                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 506                         return 2;
 507                 }
 508
 509                 /* return running physical device event */
 510                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 511                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 512                                 dbg("%llu, physical device event still running %llu (%s)",
 513                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 514                                 return 3;
 515                         }
 516         }
 517
 518         return 0;
 519 }
 520
 521 /* exec queue management routine executes the events and serializes events in the same sequence */
 522 static void msg_queue_manager(void)
 523 {
 524         struct udevd_uevent_msg *loop_msg;
 525         struct udevd_uevent_msg *tmp_msg;
 526         int running;
 527
 528         if (list_empty(&exec_list))
 529                 return;
 530
 531         running = running_processes();
 532         dbg("%d processes runnning on system", running);
 533         if (running < 0)
 534                 running = max_childs_running;
 535
 536         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 537                 /* check running processes in our session and possibly throttle */
 538                 if (running >= max_childs_running) {
 539                         running = running_processes_in_session(sid, max_childs_running+10);
 540                         dbg("at least %d processes running in session", running);
 541                         if (running >= max_childs_running) {
 542                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 543                                 return;
 544                         }
 545                 }
 546
 547                 /* don't run two processes for the same devpath and wait for the parent*/
 548                 if (running_with_devpath(loop_msg, max_childs)) {
 549                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 550                         continue;
 551                 }
 552
 553                 /* move event to run list */
 554                 list_move_tail(&loop_msg->node, &running_list);
 555                 udev_event_run(loop_msg);
 556                 running++;
 557                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 558         }
 559 }
 560
 561 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 562 {
 563         int bufpos;
 564         int i;
 565         struct udevd_uevent_msg *msg;
 566         char *physdevdriver_key = NULL;
 567         int maj = 0;
 568         int min = 0;
 569
 570         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 571         if (msg == NULL)
 572                 return NULL;
 573         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 574
 575         /* copy environment buffer and reconstruct envp */
 576         memcpy(msg->envbuf, buf, buf_size);
 577         bufpos = 0;
 578         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 579                 int keylen;
 580                 char *key;
 581
 582                 key = &msg->envbuf[bufpos];
 583                 keylen = strlen(key);
 584                 msg->envp[i] = key;
 585                 bufpos += keylen + 1;
 586                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 587
 588                 /* remember some keys for further processing */
 589                 if (strncmp(key, "ACTION=", 7) == 0)
 590                         msg->action = &key[7];
 591                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 592                         msg->devpath = &key[8];
 593                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 594                         msg->subsystem = &key[10];
 595                 else if (strncmp(key, "DRIVER=", 7) == 0)
 596                         msg->driver = &key[7];
 597                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 598                         msg->seqnum = strtoull(&key[7], NULL, 10);
 599                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 600                         msg->physdevpath = &key[12];
 601                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 602                         physdevdriver_key = key;
 603                 else if (strncmp(key, "MAJOR=", 6) == 0)
 604                         maj = strtoull(&key[6], NULL, 10);
 605                 else if (strncmp(key, "MINOR=", 6) == 0)
 606                         min = strtoull(&key[6], NULL, 10);
 607                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 608                         msg->timeout = strtoull(&key[8], NULL, 10);
 609         }
 610         msg->devt = makedev(maj, min);
 611         msg->envp[i++] = "UDEVD_EVENT=1";
 612
 613         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 614                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 615                 msg->envp[i++] = &physdevdriver_key[7];
 616                 msg->driver = &physdevdriver_key[14];
 617         }
 618
 619         msg->envp[i] = NULL;
 620
 621         if (msg->devpath == NULL || msg->action == NULL) {
 622                 info("DEVPATH or ACTION missing, ignore message");
 623                 free(msg);
 624                 return NULL;
 625         }
 626         return msg;
 627 }
 628
 629 /* receive the udevd message from userspace */
 630 static void get_ctrl_msg(void)
 631 {
 632         struct udevd_ctrl_msg ctrl_msg;
 633         ssize_t size;
 634         struct msghdr smsg;
 635         struct cmsghdr *cmsg;
 636         struct iovec iov;
 637         struct ucred *cred;
 638         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 639         int *intval;
 640
 641         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 642         iov.iov_base = &ctrl_msg;
 643         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 644
 645         memset(&smsg, 0x00, sizeof(struct msghdr));
 646         smsg.msg_iov = &iov;
 647         smsg.msg_iovlen = 1;
 648         smsg.msg_control = cred_msg;
 649         smsg.msg_controllen = sizeof(cred_msg);
 650
 651         size = recvmsg(udevd_sock, &smsg, 0);
 652         if (size <  0) {
 653                 if (errno != EINTR)
 654                         err("unable to receive user udevd message: %s", strerror(errno));
 655                 return;
 656         }
 657         cmsg = CMSG_FIRSTHDR(&smsg);
 658         cred = (struct ucred *) CMSG_DATA(cmsg);
 659
 660         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 661                 err("no sender credentials received, message ignored");
 662                 return;
 663         }
 664
 665         if (cred->uid != 0) {
 666                 err("sender uid=%i, message ignored", cred->uid);
 667                 return;
 668         }
 669
 670         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 671                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 672                 return;
 673         }
 674
 675         switch (ctrl_msg.type) {
 676         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 677                 info("udevd message (STOP_EXEC_QUEUE) received");
 678                 stop_exec_q = 1;
 679                 break;
 680         case UDEVD_CTRL_START_EXEC_QUEUE:
 681                 info("udevd message (START_EXEC_QUEUE) received");
 682                 stop_exec_q = 0;
 683                 msg_queue_manager();
 684                 break;
 685         case UDEVD_CTRL_SET_LOG_LEVEL:
 686                 intval = (int *) ctrl_msg.buf;
 687                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 688                 udev_log_priority = *intval;
 689                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 690                 putenv(udev_log);
 691                 break;
 692         case UDEVD_CTRL_SET_MAX_CHILDS:
 693                 intval = (int *) ctrl_msg.buf;
 694                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 695                 max_childs = *intval;
 696                 break;
 697         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 698                 intval = (int *) ctrl_msg.buf;
 699                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 700                 max_childs_running = *intval;
 701                 break;
 702         case UDEVD_CTRL_RELOAD_RULES:
 703                 info("udevd message (RELOAD_RULES) received");
 704                 reload_config = 1;
 705                 break;
 706         default:
 707                 err("unknown control message type");
 708         }
 709 }
 710
 711 /* receive the kernel user event message and do some sanity checks */
 712 static struct udevd_uevent_msg *get_netlink_msg(void)
 713 {
 714         struct udevd_uevent_msg *msg;
 715         int bufpos;
 716         ssize_t size;
 717         static char buffer[UEVENT_BUFFER_SIZE+512];
 718         char *pos;
 719
 720         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 721         if (size <  0) {
 722                 if (errno != EINTR)
 723                         err("unable to receive kernel netlink message: %s", strerror(errno));
 724                 return NULL;
 725         }
 726
 727         if ((size_t)size > sizeof(buffer)-1)
 728                 size = sizeof(buffer)-1;
 729         buffer[size] = '\0';
 730         dbg("uevent_size=%zi", size);
 731
 732         /* start of event payload */
 733         bufpos = strlen(buffer)+1;
 734         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 735         if (msg == NULL)
 736                 return NULL;
 737
 738         /* validate message */
 739         pos = strchr(buffer, '@');
 740         if (pos == NULL) {
 741                 err("invalid uevent '%s'", buffer);
 742                 free(msg);
 743                 return NULL;
 744         }
 745         pos[0] = '\0';
 746
 747         if (msg->action == NULL) {
 748                 info("no ACTION in payload found, skip event '%s'", buffer);
 749                 free(msg);
 750                 return NULL;
 751         }
 752
 753         if (strcmp(msg->action, buffer) != 0) {
 754                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 755                 free(msg);
 756                 return NULL;
 757         }
 758
 759         return msg;
 760 }
 761
 762 static void asmlinkage sig_handler(int signum)
 763 {
 764         switch (signum) {
 765                 case SIGINT:
 766                 case SIGTERM:
 767                         udev_exit = 1;
 768                         break;
 769                 case SIGCHLD:
 770                         /* set flag, then write to pipe if needed */
 771                         sigchilds_waiting = 1;
 772                         break;
 773                 case SIGHUP:
 774                         reload_config = 1;
 775                         break;
 776         }
 777
 778         /* write to pipe, which will wakeup select() in our mainloop */
 779         write(signal_pipe[WRITE_END], "", 1);
 780 }
 781
 782 static void udev_done(int pid, int exitstatus)
 783 {
 784         /* find msg associated with pid and delete it */
 785         struct udevd_uevent_msg *msg;
 786
 787         list_for_each_entry(msg, &running_list, node) {
 788                 if (msg->pid == pid) {
 789                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 790                              exitstatus, time(NULL) - msg->queue_time);
 791                         msg->exitstatus = exitstatus;
 792                         msg_queue_delete(msg);
 793
 794                         /* there may be events waiting with the same devpath */
 795                         run_exec_q = 1;
 796                         return;
 797                 }
 798         }
 799 }
 800
 801 static void reap_sigchilds(void)
 802 {
 803         pid_t pid;
 804         int status;
 805
 806         while (1) {
 807                 pid = waitpid(-1, &status, WNOHANG);
 808                 if (pid <= 0)
 809                         break;
 810                 if (WIFEXITED(status))
 811                         status = WEXITSTATUS(status);
 812                 else if (WIFSIGNALED(status))
 813                         status = WTERMSIG(status) + 128;
 814                 else
 815                         status = 0;
 816                 udev_done(pid, status);
 817         }
 818 }
 819
 820 static int init_udevd_socket(void)
 821 {
 822         struct sockaddr_un saddr;
 823         socklen_t addrlen;
 824         const int feature_on = 1;
 825         int retval;
 826
 827         memset(&saddr, 0x00, sizeof(saddr));
 828         saddr.sun_family = AF_LOCAL;
 829         /* use abstract namespace for socket path */
 830         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 831         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 832
 833         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 834         if (udevd_sock == -1) {
 835                 err("error getting socket: %s", strerror(errno));
 836                 return -1;
 837         }
 838
 839         /* the bind takes care of ensuring only one copy running */
 840         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 841         if (retval < 0) {
 842                 err("bind failed: %s", strerror(errno));
 843                 close(udevd_sock);
 844                 udevd_sock = -1;
 845                 return -1;
 846         }
 847
 848         /* enable receiving of the sender credentials */
 849         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 850
 851         return 0;
 852 }
 853
 854 static int init_uevent_netlink_sock(void)
 855 {
 856         struct sockaddr_nl snl;
 857         const int buffersize = 16 * 1024 * 1024;
 858         int retval;
 859
 860         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 861         snl.nl_family = AF_NETLINK;
 862         snl.nl_pid = getpid();
 863         snl.nl_groups = 1;
 864
 865         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 866         if (uevent_netlink_sock == -1) {
 867                 err("error getting socket: %s", strerror(errno));
 868                 return -1;
 869         }
 870
 871         /* set receive buffersize */
 872         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 873
 874         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 875         if (retval < 0) {
 876                 err("bind failed: %s", strerror(errno));
 877                 close(uevent_netlink_sock);
 878                 uevent_netlink_sock = -1;
 879                 return -1;
 880         }
 881         return 0;
 882 }
 883
 884 static void export_initial_seqnum(void)
 885 {
 886         char filename[PATH_SIZE];
 887         int fd;
 888         char seqnum[32];
 889         ssize_t len = 0;
 890
 891         strlcpy(filename, sysfs_path, sizeof(filename));
 892         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 893         fd = open(filename, O_RDONLY);
 894         if (fd >= 0) {
 895                 len = read(fd, seqnum, sizeof(seqnum)-1);
 896                 close(fd);
 897         }
 898         if (len <= 0) {
 899                 strcpy(seqnum, "0\n");
 900                 len = 3;
 901         }
 902         strlcpy(filename, udev_root, sizeof(filename));
 903         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 904         create_path(filename);
 905         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 906         if (fd >= 0) {
 907                 write(fd, seqnum, len);
 908                 close(fd);
 909         }
 910 }
 911
 912 int main(int argc, char *argv[], char *envp[])
 913 {
 914         int retval;
 915         int fd;
 916         struct sigaction act;
 917         fd_set readfds;
 918         const char *value;
 919         int daemonize = 0;
 920         int i;
 921         int rc = 1;
 922         int maxfd;
 923
 924         logging_init("udevd");
 925         udev_config_init();
 926         selinux_init();
 927         dbg("version %s", UDEV_VERSION);
 928
 929         /* parse commandline options */
 930         for (i = 1 ; i < argc; i++) {
 931                 char *arg = argv[i];
 932                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0)
 933                         daemonize = 1;
 934                 else if (strcmp(arg, "--help") == 0 || strcmp(arg, "-h") == 0) {
 935                         printf("Usage: udevd [--help] [--daemon]\n");
 936                         goto exit;
 937                 } else {
 938                         fprintf(stderr, "unrecognized option '%s'\n", arg);
 939                         err("unrecognized option '%s'\n", arg);
 940                 }
 941         }
 942
 943         if (getuid() != 0) {
 944                 fprintf(stderr, "root privileges required\n");
 945                 err("root privileges required");
 946                 goto exit;
 947         }
 948
 949         /* init sockets to receive events */
 950         if (init_udevd_socket() < 0) {
 951                 if (errno == EADDRINUSE) {
 952                         fprintf(stderr, "another udev daemon already running\n");
 953                         err("another udev daemon already running");
 954                         rc = 1;
 955                 } else {
 956                         fprintf(stderr, "error initializing udevd socket\n");
 957                         err("error initializing udevd socket");
 958                         rc = 2;
 959                 }
 960                 goto exit;
 961         }
 962
 963         if (init_uevent_netlink_sock() < 0) {
 964                 fprintf(stderr, "error initializing netlink socket\n");
 965                 err("error initializing netlink socket");
 966                 rc = 3;
 967                 goto exit;
 968         }
 969
 970         /* parse the rules and keep them in memory */
 971         sysfs_init();
 972         udev_rules_init(&rules, 1);
 973
 974         export_initial_seqnum();
 975
 976         if (daemonize) {
 977                 pid_t pid;
 978
 979                 pid = fork();
 980                 switch (pid) {
 981                 case 0:
 982                         dbg("daemonized fork running");
 983                         break;
 984                 case -1:
 985                         err("fork of daemon failed: %s", strerror(errno));
 986                         rc = 4;
 987                         goto exit;
 988                 default:
 989                         dbg("child [%u] running, parent exits", pid);
 990                         rc = 0;
 991                         goto exit;
 992                 }
 993         }
 994
 995         /* redirect std fd's */
 996         fd = open("/dev/null", O_RDWR);
 997         if (fd >= 0) {
 998                 dup2(fd, STDIN_FILENO);
 999                 dup2(fd, STDOUT_FILENO);
1000                 dup2(fd, STDERR_FILENO);
1001                 if (fd > STDERR_FILENO)
1002                         close(fd);
1003         } else
1004                 err("error opening /dev/null: %s", strerror(errno));
1005
1006         /* set scheduling priority for the daemon */
1007         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1008
1009         chdir("/");
1010         umask(022);
1011
1012         /* become session leader */
1013         sid = setsid();
1014         dbg("our session is %d", sid);
1015
1016         /* OOM_DISABLE == -17 */
1017         fd = open("/proc/self/oom_adj", O_RDWR);
1018         if (fd < 0)
1019                 err("error disabling OOM: %s", strerror(errno));
1020         else {
1021                 write(fd, "-17", 3);
1022                 close(fd);
1023         }
1024
1025         /* setup signal handler pipe */
1026         retval = pipe(signal_pipe);
1027         if (retval < 0) {
1028                 err("error getting pipes: %s", strerror(errno));
1029                 goto exit;
1030         }
1031
1032         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1033         if (retval < 0) {
1034                 err("error fcntl on read pipe: %s", strerror(errno));
1035                 goto exit;
1036         }
1037         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1038         if (retval < 0) {
1039                 err("error fcntl on read pipe: %s", strerror(errno));
1040                 goto exit;
1041         }
1042
1043         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1044         if (retval < 0) {
1045                 err("error fcntl on write pipe: %s", strerror(errno));
1046                 goto exit;
1047         }
1048         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1049         if (retval < 0) {
1050                 err("error fcntl on write pipe: %s", strerror(errno));
1051                 goto exit;
1052         }
1053
1054         /* set signal handlers */
1055         memset(&act, 0x00, sizeof(struct sigaction));
1056         act.sa_handler = (void (*)(int)) sig_handler;
1057         sigemptyset(&act.sa_mask);
1058         act.sa_flags = SA_RESTART;
1059         sigaction(SIGINT, &act, NULL);
1060         sigaction(SIGTERM, &act, NULL);
1061         sigaction(SIGCHLD, &act, NULL);
1062         sigaction(SIGHUP, &act, NULL);
1063
1064         /* watch rules directory */
1065         inotify_fd = inotify_init();
1066         if (inotify_fd >= 0)
1067                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1068         else if (errno == ENOSYS)
1069                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1070         else
1071                 err("inotify_init failed: %s", strerror(errno));
1072
1073         /* maximum limit of forked childs */
1074         value = getenv("UDEVD_MAX_CHILDS");
1075         if (value)
1076                 max_childs = strtoul(value, NULL, 10);
1077         else {
1078                 int memsize = mem_size_mb();
1079                 if (memsize > 0)
1080                         max_childs = 128 + (memsize / 4);
1081                 else
1082                         max_childs = UDEVD_MAX_CHILDS;
1083         }
1084         info("initialize max_childs to %u", max_childs);
1085
1086         /* start to throttle forking if maximum number of _running_ childs is reached */
1087         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1088         if (value)
1089                 max_childs_running = strtoull(value, NULL, 10);
1090         else {
1091                 int cpus = cpu_count();
1092                 if (cpus > 0)
1093                         max_childs_running = 8 + (8 * cpus);
1094                 else
1095                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1096         }
1097         info("initialize max_childs_running to %u", max_childs_running);
1098
1099         /* clear environment for forked event processes */
1100         clearenv();
1101
1102         /* export log_priority , as called programs may want to follow that setting */
1103         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1104         putenv(udev_log);
1105
1106         maxfd = udevd_sock;
1107         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1108         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1109         maxfd = UDEV_MAX(maxfd, inotify_fd);
1110
1111         while (!udev_exit) {
1112                 struct udevd_uevent_msg *msg;
1113                 int fdcount;
1114
1115                 FD_ZERO(&readfds);
1116                 FD_SET(signal_pipe[READ_END], &readfds);
1117                 FD_SET(udevd_sock, &readfds);
1118                 FD_SET(uevent_netlink_sock, &readfds);
1119                 if (inotify_fd >= 0)
1120                         FD_SET(inotify_fd, &readfds);
1121
1122                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1123                 if (fdcount < 0) {
1124                         if (errno != EINTR)
1125                                 err("error in select: %s", strerror(errno));
1126                         continue;
1127                 }
1128
1129                 /* get control message */
1130                 if (FD_ISSET(udevd_sock, &readfds))
1131                         get_ctrl_msg();
1132
1133                 /* get netlink message */
1134                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1135                         msg = get_netlink_msg();
1136                         if (msg)
1137                                 msg_queue_insert(msg);
1138                 }
1139
1140                 /* received a signal, clear our notification pipe */
1141                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1142                         char buf[256];
1143
1144                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1145                 }
1146
1147                 /* rules directory inotify watch */
1148                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1149                         int nbytes;
1150
1151                         /* discard all possible events, we can just reload the config */
1152                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1153                                 char *buf;
1154
1155                                 reload_config = 1;
1156                                 buf = malloc(nbytes);
1157                                 if (!buf) {
1158                                         err("error getting buffer for inotify, disable watching");
1159                                         close(inotify_fd);
1160                                         inotify_fd = -1;
1161                                 }
1162                                 read(inotify_fd, buf, nbytes);
1163                                 free(buf);
1164                         }
1165                 }
1166
1167                 /* rules changed, set by inotify or a HUP signal */
1168                 if (reload_config) {
1169                         reload_config = 0;
1170                         udev_rules_cleanup(&rules);
1171                         udev_rules_init(&rules, 1);
1172                 }
1173
1174                 /* forked child has returned */
1175                 if (sigchilds_waiting) {
1176                         sigchilds_waiting = 0;
1177                         reap_sigchilds();
1178                 }
1179
1180                 if (run_exec_q) {
1181                         run_exec_q = 0;
1182                         if (!stop_exec_q)
1183                                 msg_queue_manager();
1184                 }
1185         }
1186         rc = 0;
1187
1188 exit:
1189         udev_rules_cleanup(&rules);
1190         sysfs_cleanup();
1191
1192         if (signal_pipe[READ_END] >= 0)
1193                 close(signal_pipe[READ_END]);
1194         if (signal_pipe[WRITE_END] >= 0)
1195                 close(signal_pipe[WRITE_END]);
1196
1197         if (udevd_sock >= 0)
1198                 close(udevd_sock);
1199         if (inotify_fd >= 0)
1200                 close(inotify_fd);
1201         if (uevent_netlink_sock >= 0)
1202                 close(uevent_netlink_sock);
1203
1204         logging_close();
1205
1206         return rc;
1207 }