udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   6  *
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stddef.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <time.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47 #include "udevd.h"
  48
  49 static struct udev_rules rules;
  50 static int udevd_sock;
  51 static int uevent_netlink_sock;
  52 static int inotify_fd;
  53 static pid_t sid;
  54
  55 static int signal_pipe[2] = {-1, -1};
  56 static volatile int sigchilds_waiting;
  57 static volatile int udev_exit;
  58 static volatile int reload_config;
  59 static int run_exec_q;
  60 static int stop_exec_q;
  61 static int max_childs;
  62 static int max_childs_running;
  63 static char udev_log[32];
  64
  65 static LIST_HEAD(exec_list);
  66 static LIST_HEAD(running_list);
  67
  68
  69 #ifdef USE_LOG
  70 void log_message(int priority, const char *format, ...)
  71 {
  72         va_list args;
  73
  74         if (priority > udev_log_priority)
  75                 return;
  76
  77         va_start(args, format);
  78         vsyslog(priority, format, args);
  79         va_end(args);
  80 }
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* trigger timeout to prevent hanging processes */
 104         alarm(UDEV_ALARM_TIMEOUT);
 105
 106         /* reconstruct event environment from message */
 107         for (i = 0; msg->envp[i]; i++)
 108                 putenv(msg->envp[i]);
 109
 110         udev = udev_device_init();
 111         if (udev == NULL)
 112                 return -1;
 113         strlcpy(udev->action, msg->action, sizeof(udev->action));
 114         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
 115         udev->devt = msg->devt;
 116
 117         retval = udev_device_event(&rules, udev);
 118
 119         /* run programs collected by RUN-key*/
 120         if (retval == 0 && !udev->ignore_device && udev_run) {
 121                 struct name_entry *name_loop;
 122
 123                 dbg("executing run list");
 124                 list_for_each_entry(name_loop, &udev->run_list, node) {
 125                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 126                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
 127                         else {
 128                                 char program[PATH_SIZE];
 129
 130                                 strlcpy(program, name_loop->name, sizeof(program));
 131                                 udev_rules_apply_format(udev, program, sizeof(program));
 132                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 133                                                 (udev_log_priority >= LOG_INFO)))
 134                                         retval = -1;
 135                         }
 136                 }
 137         }
 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 uevent_msg *msg, enum event_state state)
 150 {
 151         char filename[PATH_SIZE];
 152         char filename_failed[PATH_SIZE];
 153         char target[PATH_SIZE];
 154         size_t start, end, i;
 155         struct uevent_msg *loop_msg;
 156
 157         /* add location of queue files */
 158         strlcpy(filename, udev_root, sizeof(filename));
 159         strlcat(filename, "/", sizeof(filename));
 160         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 161         end = strlcat(filename, msg->devpath, sizeof(filename));
 162         if (end > sizeof(filename))
 163                 end = sizeof(filename);
 164
 165         /* replace '/' to transform path into a filename */
 166         for (i = start+1; i < end; i++)
 167                 if (filename[i] == '/')
 168                         filename[i] = PATH_TO_NAME_CHAR;
 169
 170         /* add location of failed files */
 171         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 172         strlcat(filename_failed, "/", sizeof(filename_failed));
 173         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 174         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 175         if (end > sizeof(filename_failed))
 176                 end = sizeof(filename_failed);
 177
 178         /* replace '/' to transform path into a filename */
 179         for (i = start+1; i < end; i++)
 180                 if (filename_failed[i] == '/')
 181                         filename_failed[i] = PATH_TO_NAME_CHAR;
 182
 183         switch (state) {
 184         case EVENT_QUEUED:
 185                 unlink(filename_failed);
 186                 delete_path(filename_failed);
 187
 188                 strlcpy(target, sysfs_path, sizeof(target));
 189                 strlcat(target, msg->devpath, sizeof(target));
 190                 create_path(filename);
 191                 symlink(target, filename);
 192                 return;
 193         case EVENT_FINISHED:
 194         case EVENT_FAILED:
 195                 unlink(filename_failed);
 196                 delete_path(filename_failed);
 197
 198                 /* don't remove, if events for the same path are still pending */
 199                 list_for_each_entry(loop_msg, &running_list, node)
 200                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 201                                 return;
 202
 203                 /* move failed events to the failed directory */
 204                 if (state == EVENT_FAILED) {
 205                         create_path(filename_failed);
 206                         rename(filename, filename_failed);
 207                 } else {
 208                         unlink(filename);
 209                 }
 210
 211                 /* clean up the queue directory */
 212                 delete_path(filename);
 213
 214                 return;
 215         }
 216 }
 217
 218 static void msg_queue_delete(struct uevent_msg *msg)
 219 {
 220         list_del(&msg->node);
 221
 222         /* mark as failed, if add event returns non-zero */
 223         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 224                 export_event_state(msg, EVENT_FAILED);
 225         else
 226                 export_event_state(msg, EVENT_FINISHED);
 227
 228         free(msg);
 229 }
 230
 231 static void udev_event_run(struct uevent_msg *msg)
 232 {
 233         pid_t pid;
 234         int retval;
 235
 236         pid = fork();
 237         switch (pid) {
 238         case 0:
 239                 /* child */
 240                 close(uevent_netlink_sock);
 241                 close(udevd_sock);
 242                 if (inotify_fd > 0)
 243                         close(inotify_fd);
 244                 close(signal_pipe[READ_END]);
 245                 close(signal_pipe[WRITE_END]);
 246                 logging_close();
 247
 248                 logging_init("udevd-event");
 249                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 250                 retval = udev_event_process(msg);
 251                 info("seq %llu finished", msg->seqnum);
 252
 253                 logging_close();
 254                 if (retval)
 255                         exit(1);
 256                 exit(0);
 257         case -1:
 258                 err("fork of child failed: %s", strerror(errno));
 259                 msg_queue_delete(msg);
 260                 break;
 261         default:
 262                 /* get SIGCHLD in main loop */
 263                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 264                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 265                 msg->pid = pid;
 266         }
 267 }
 268
 269 static void msg_queue_insert(struct uevent_msg *msg)
 270 {
 271         msg->queue_time = time(NULL);
 272
 273         export_event_state(msg, EVENT_QUEUED);
 274
 275         /* run all events with a timeout set immediately */
 276         if (msg->timeout != 0) {
 277                 list_add_tail(&msg->node, &running_list);
 278                 udev_event_run(msg);
 279                 return;
 280         }
 281
 282         list_add_tail(&msg->node, &exec_list);
 283         run_exec_q = 1;
 284 }
 285
 286 /* runs event and removes event from run queue when finished */
 287 static int running_processes(void)
 288 {
 289         int f;
 290         static char buf[4096];
 291         int len;
 292         int running;
 293         const char *pos;
 294
 295         f = open("/proc/stat", O_RDONLY);
 296         if (f == -1)
 297                 return -1;
 298
 299         len = read(f, buf, sizeof(buf)-1);
 300         close(f);
 301
 302         if (len <= 0)
 303                 return -1;
 304         else
 305                 buf[len] = '\0';
 306
 307         pos = strstr(buf, "procs_running ");
 308         if (pos == NULL)
 309                 return -1;
 310
 311         if (sscanf(pos, "procs_running %u", &running) != 1)
 312                 return -1;
 313
 314         return running;
 315 }
 316
 317 /* return the number of process es in our session, count only until limit */
 318 static int running_processes_in_session(pid_t session, int limit)
 319 {
 320         DIR *dir;
 321         struct dirent *dent;
 322         int running = 0;
 323
 324         dir = opendir("/proc");
 325         if (!dir)
 326                 return -1;
 327
 328         /* read process info from /proc */
 329         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 330                 int f;
 331                 char procdir[64];
 332                 char line[256];
 333                 const char *pos;
 334                 char state;
 335                 pid_t ppid, pgrp, sess;
 336                 int len;
 337
 338                 if (!isdigit(dent->d_name[0]))
 339                         continue;
 340
 341                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 342                 procdir[sizeof(procdir)-1] = '\0';
 343
 344                 f = open(procdir, O_RDONLY);
 345                 if (f == -1)
 346                         continue;
 347
 348                 len = read(f, line, sizeof(line)-1);
 349                 close(f);
 350
 351                 if (len <= 0)
 352                         continue;
 353                 else
 354                         line[len] = '\0';
 355
 356                 /* skip ugly program name */
 357                 pos = strrchr(line, ')') + 2;
 358                 if (pos == NULL)
 359                         continue;
 360
 361                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 362                         continue;
 363
 364                 /* count only processes in our session */
 365                 if (sess != session)
 366                         continue;
 367
 368                 /* count only running, no sleeping processes */
 369                 if (state != 'R')
 370                         continue;
 371
 372                 running++;
 373                 if (limit > 0 && running >= limit)
 374                         break;
 375         }
 376         closedir(dir);
 377
 378         return running;
 379 }
 380
 381 static int compare_devpath(const char *running, const char *waiting)
 382 {
 383         int i;
 384
 385         for (i = 0; i < PATH_SIZE; i++) {
 386                 /* identical device event found */
 387                 if (running[i] == '\0' && waiting[i] == '\0')
 388                         return 1;
 389
 390                 /* parent device event found */
 391                 if (running[i] == '\0' && waiting[i] == '/')
 392                         return 2;
 393
 394                 /* child device event found */
 395                 if (running[i] == '/' && waiting[i] == '\0')
 396                         return 3;
 397
 398                 /* no matching event */
 399                 if (running[i] != waiting[i])
 400                         break;
 401         }
 402
 403         return 0;
 404 }
 405
 406 /* returns still running task for the same device, its parent or its physical device */
 407 static int running_with_devpath(struct uevent_msg *msg, int limit)
 408 {
 409         struct uevent_msg *loop_msg;
 410         int childs_count = 0;
 411
 412         list_for_each_entry(loop_msg, &running_list, node) {
 413                 if (limit && childs_count++ > limit) {
 414                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 415                         return 1;
 416                 }
 417
 418                 /* return running parent/child device event */
 419                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 420                         dbg("%llu, child device event still running %llu (%s)",
 421                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 422                         return 2;
 423                 }
 424
 425                 /* return running physical device event */
 426                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 427                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 428                                 dbg("%llu, physical device event still running %llu (%s)",
 429                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 430                                 return 3;
 431                         }
 432         }
 433
 434         return 0;
 435 }
 436
 437 /* exec queue management routine executes the events and serializes events in the same sequence */
 438 static void msg_queue_manager(void)
 439 {
 440         struct uevent_msg *loop_msg;
 441         struct uevent_msg *tmp_msg;
 442         int running;
 443
 444         if (list_empty(&exec_list))
 445                 return;
 446
 447         running = running_processes();
 448         dbg("%d processes runnning on system", running);
 449         if (running < 0)
 450                 running = max_childs_running;
 451
 452         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 453                 /* check running processes in our session and possibly throttle */
 454                 if (running >= max_childs_running) {
 455                         running = running_processes_in_session(sid, max_childs_running+10);
 456                         dbg("at least %d processes running in session", running);
 457                         if (running >= max_childs_running) {
 458                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 459                                 return;
 460                         }
 461                 }
 462
 463                 /* don't run two processes for the same devpath and wait for the parent*/
 464                 if (running_with_devpath(loop_msg, max_childs)) {
 465                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 466                         continue;
 467                 }
 468
 469                 /* move event to run list */
 470                 list_move_tail(&loop_msg->node, &running_list);
 471                 udev_event_run(loop_msg);
 472                 running++;
 473                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 474         }
 475 }
 476
 477 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 478 {
 479         int bufpos;
 480         int i;
 481         struct uevent_msg *msg;
 482         int major = 0;
 483         int minor = 0;
 484
 485         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 486         if (msg == NULL)
 487                 return NULL;
 488         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 489
 490         /* copy environment buffer and reconstruct envp */
 491         memcpy(msg->envbuf, buf, buf_size);
 492         bufpos = 0;
 493         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 494                 int keylen;
 495                 char *key;
 496
 497                 key = &msg->envbuf[bufpos];
 498                 keylen = strlen(key);
 499                 msg->envp[i] = key;
 500                 bufpos += keylen + 1;
 501                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 502
 503                 /* remember some keys for further processing */
 504                 if (strncmp(key, "ACTION=", 7) == 0)
 505                         msg->action = &key[7];
 506                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 507                         msg->devpath = &key[8];
 508                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 509                         msg->subsystem = &key[10];
 510                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 511                         msg->seqnum = strtoull(&key[7], NULL, 10);
 512                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 513                         msg->physdevpath = &key[12];
 514                 else if (strncmp(key, "MAJOR=", 6) == 0)
 515                         major = strtoull(&key[6], NULL, 10);
 516                 else if (strncmp(key, "MINOR=", 6) == 0)
 517                         minor = strtoull(&key[6], NULL, 10);
 518                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 519                         msg->timeout = strtoull(&key[8], NULL, 10);
 520         }
 521         msg->devt = makedev(major, minor);
 522         msg->envp[i++] = "UDEVD_EVENT=1";
 523         msg->envp[i] = NULL;
 524
 525         if (msg->devpath == NULL || msg->action == NULL) {
 526                 info("DEVPATH or ACTION missing, ignore message");
 527                 free(msg);
 528                 return NULL;
 529         }
 530         return msg;
 531 }
 532
 533 /* receive the udevd message from userspace */
 534 static struct uevent_msg *get_udevd_msg(void)
 535 {
 536         static struct udevd_msg usend_msg;
 537         struct uevent_msg *msg;
 538         ssize_t size;
 539         struct msghdr smsg;
 540         struct cmsghdr *cmsg;
 541         struct iovec iov;
 542         struct ucred *cred;
 543         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 544         int envbuf_size;
 545         int *intval;
 546
 547         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 548         iov.iov_base = &usend_msg;
 549         iov.iov_len = sizeof(struct udevd_msg);
 550
 551         memset(&smsg, 0x00, sizeof(struct msghdr));
 552         smsg.msg_iov = &iov;
 553         smsg.msg_iovlen = 1;
 554         smsg.msg_control = cred_msg;
 555         smsg.msg_controllen = sizeof(cred_msg);
 556
 557         size = recvmsg(udevd_sock, &smsg, 0);
 558         if (size <  0) {
 559                 if (errno != EINTR)
 560                         err("unable to receive user udevd message: %s", strerror(errno));
 561                 return NULL;
 562         }
 563         cmsg = CMSG_FIRSTHDR(&smsg);
 564         cred = (struct ucred *) CMSG_DATA(cmsg);
 565
 566         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 567                 err("no sender credentials received, message ignored");
 568                 return NULL;
 569         }
 570
 571         if (cred->uid != 0) {
 572                 err("sender uid=%i, message ignored", cred->uid);
 573                 return NULL;
 574         }
 575
 576         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 577                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 578                 return NULL;
 579         }
 580
 581         switch (usend_msg.type) {
 582         case UDEVD_UEVENT_UDEVSEND:
 583                 info("udevd event message received");
 584                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 585                 dbg("envbuf_size=%i", envbuf_size);
 586                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 587                 if (msg == NULL)
 588                         return NULL;
 589                 msg->type = usend_msg.type;
 590                 return msg;
 591         case UDEVD_STOP_EXEC_QUEUE:
 592                 info("udevd message (STOP_EXEC_QUEUE) received");
 593                 stop_exec_q = 1;
 594                 break;
 595         case UDEVD_START_EXEC_QUEUE:
 596                 info("udevd message (START_EXEC_QUEUE) received");
 597                 stop_exec_q = 0;
 598                 msg_queue_manager();
 599                 break;
 600         case UDEVD_SET_LOG_LEVEL:
 601                 intval = (int *) usend_msg.envbuf;
 602                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 603                 udev_log_priority = *intval;
 604                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 605                 putenv(udev_log);
 606                 break;
 607         case UDEVD_SET_MAX_CHILDS:
 608                 intval = (int *) usend_msg.envbuf;
 609                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 610                 max_childs = *intval;
 611                 break;
 612         case UDEVD_RELOAD_RULES:
 613                 info("udevd message (RELOAD_RULES) received");
 614                 reload_config = 1;
 615                 break;
 616         default:
 617                 dbg("unknown message type");
 618         }
 619         return NULL;
 620 }
 621
 622 /* receive the kernel user event message and do some sanity checks */
 623 static struct uevent_msg *get_netlink_msg(void)
 624 {
 625         struct uevent_msg *msg;
 626         int bufpos;
 627         ssize_t size;
 628         static char buffer[UEVENT_BUFFER_SIZE+512];
 629         char *pos;
 630
 631         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 632         if (size <  0) {
 633                 if (errno != EINTR)
 634                         err("unable to receive kernel netlink message: %s", strerror(errno));
 635                 return NULL;
 636         }
 637
 638         if ((size_t)size > sizeof(buffer)-1)
 639                 size = sizeof(buffer)-1;
 640         buffer[size] = '\0';
 641         dbg("uevent_size=%zi", size);
 642
 643         /* start of event payload */
 644         bufpos = strlen(buffer)+1;
 645         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 646         if (msg == NULL)
 647                 return NULL;
 648         msg->type = UDEVD_UEVENT_NETLINK;
 649
 650         /* validate message */
 651         pos = strchr(buffer, '@');
 652         if (pos == NULL) {
 653                 err("invalid uevent '%s'", buffer);
 654                 free(msg);
 655                 return NULL;
 656         }
 657         pos[0] = '\0';
 658
 659         if (msg->action == NULL) {
 660                 info("no ACTION in payload found, skip event '%s'", buffer);
 661                 free(msg);
 662                 return NULL;
 663         }
 664
 665         if (strcmp(msg->action, buffer) != 0) {
 666                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 667                 free(msg);
 668                 return NULL;
 669         }
 670
 671         return msg;
 672 }
 673
 674 static void asmlinkage sig_handler(int signum)
 675 {
 676         switch (signum) {
 677                 case SIGINT:
 678                 case SIGTERM:
 679                         udev_exit = 1;
 680                         break;
 681                 case SIGCHLD:
 682                         /* set flag, then write to pipe if needed */
 683                         sigchilds_waiting = 1;
 684                         break;
 685                 case SIGHUP:
 686                         reload_config = 1;
 687                         break;
 688         }
 689
 690         /* write to pipe, which will wakeup select() in our mainloop */
 691         write(signal_pipe[WRITE_END], "", 1);
 692 }
 693
 694 static void udev_done(int pid, int exitstatus)
 695 {
 696         /* find msg associated with pid and delete it */
 697         struct uevent_msg *msg;
 698
 699         list_for_each_entry(msg, &running_list, node) {
 700                 if (msg->pid == pid) {
 701                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 702                              exitstatus, time(NULL) - msg->queue_time);
 703                         msg->exitstatus = exitstatus;
 704                         msg_queue_delete(msg);
 705
 706                         /* there may be events waiting with the same devpath */
 707                         run_exec_q = 1;
 708                         return;
 709                 }
 710         }
 711 }
 712
 713 static void reap_sigchilds(void)
 714 {
 715         pid_t pid;
 716         int status;
 717
 718         while (1) {
 719                 pid = waitpid(-1, &status, WNOHANG);
 720                 if (pid <= 0)
 721                         break;
 722                 if (WIFEXITED(status))
 723                         status = WEXITSTATUS(status);
 724                 else if (WIFSIGNALED(status))
 725                         status = WTERMSIG(status) + 128;
 726                 else
 727                         status = 0;
 728                 udev_done(pid, status);
 729         }
 730 }
 731
 732 static int init_udevd_socket(void)
 733 {
 734         struct sockaddr_un saddr;
 735         const int buffersize = 16 * 1024 * 1024;
 736         socklen_t addrlen;
 737         const int feature_on = 1;
 738         int retval;
 739
 740         memset(&saddr, 0x00, sizeof(saddr));
 741         saddr.sun_family = AF_LOCAL;
 742         /* use abstract namespace for socket path */
 743         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 744         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 745
 746         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 747         if (udevd_sock == -1) {
 748                 err("error getting socket: %s", strerror(errno));
 749                 return -1;
 750         }
 751
 752         /* set receive buffersize */
 753         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 754
 755         /* the bind takes care of ensuring only one copy running */
 756         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 757         if (retval < 0) {
 758                 err("bind failed: %s", strerror(errno));
 759                 return -1;
 760         }
 761
 762         /* enable receiving of the sender credentials */
 763         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 764
 765         return 0;
 766 }
 767
 768 static int init_uevent_netlink_sock(void)
 769 {
 770         struct sockaddr_nl snl;
 771         const int buffersize = 16 * 1024 * 1024;
 772         int retval;
 773
 774         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 775         snl.nl_family = AF_NETLINK;
 776         snl.nl_pid = getpid();
 777         snl.nl_groups = 0xffffffff;
 778
 779         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 780         if (uevent_netlink_sock == -1) {
 781                 err("error getting socket: %s", strerror(errno));
 782                 return -1;
 783         }
 784
 785         /* set receive buffersize */
 786         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 787
 788         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 789         if (retval < 0) {
 790                 err("bind failed: %s", strerror(errno));
 791                 close(uevent_netlink_sock);
 792                 uevent_netlink_sock = -1;
 793                 return -1;
 794         }
 795         return 0;
 796 }
 797
 798 int main(int argc, char *argv[], char *envp[])
 799 {
 800         int retval;
 801         int fd;
 802         struct sigaction act;
 803         fd_set readfds;
 804         const char *value;
 805         int daemonize = 0;
 806         int i;
 807         int rc = 0;
 808         int maxfd;
 809
 810         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 811         fd = open("/dev/null", O_RDWR);
 812         if (fd >= 0) {
 813                 if (fd != STDIN_FILENO)
 814                         dup2(fd, STDIN_FILENO);
 815                 if (fd != STDOUT_FILENO)
 816                         dup2(fd, STDOUT_FILENO);
 817                 if (fd != STDERR_FILENO)
 818                         dup2(fd, STDERR_FILENO);
 819                 if (fd > STDERR_FILENO)
 820                         close(fd);
 821         }
 822
 823         logging_init("udevd");
 824         if (fd < 0)
 825                 err("fatal, could not open /dev/null: %s", strerror(errno));
 826
 827         udev_config_init();
 828         dbg("version %s", UDEV_VERSION);
 829
 830         if (getuid() != 0) {
 831                 err("need to be root, exit");
 832                 goto exit;
 833         }
 834
 835         /* parse commandline options */
 836         for (i = 1 ; i < argc; i++) {
 837                 char *arg = argv[i];
 838                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 839                         info("will daemonize");
 840                         daemonize = 1;
 841                 }
 842                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 843                         info("will not execute events until START_EXEC_QUEUE is received");
 844                         stop_exec_q = 1;
 845                 }
 846         }
 847
 848         /* init sockets to receive events */
 849         if (init_udevd_socket() < 0) {
 850                 if (errno == EADDRINUSE) {
 851                         err("another udevd running, exit");
 852                         rc = 1;
 853                 } else {
 854                         err("error initializing udevd socket: %s", strerror(errno));
 855                         rc = 2;
 856                 }
 857                 goto exit;
 858         }
 859
 860         if (init_uevent_netlink_sock() < 0) {
 861                 err("uevent socket not available");
 862                 rc = 3;
 863                 goto exit;
 864         }
 865
 866         /* parse the rules and keep it in memory */
 867         sysfs_init();
 868         udev_rules_init(&rules, 1);
 869
 870         if (daemonize) {
 871                 pid_t pid;
 872
 873                 pid = fork();
 874                 switch (pid) {
 875                 case 0:
 876                         dbg("daemonized fork running");
 877                         break;
 878                 case -1:
 879                         err("fork of daemon failed: %s", strerror(errno));
 880                         rc = 4;
 881                         goto exit;
 882                 default:
 883                         dbg("child [%u] running, parent exits", pid);
 884                         goto exit;
 885                 }
 886         }
 887
 888         /* set scheduling priority for the daemon */
 889         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 890
 891         chdir("/");
 892         umask(022);
 893
 894         /* become session leader */
 895         sid = setsid();
 896         dbg("our session is %d", sid);
 897
 898         /* OOM_DISABLE == -17 */
 899         fd = open("/proc/self/oom_adj", O_RDWR);
 900         if (fd < 0)
 901                 err("error disabling OOM: %s", strerror(errno));
 902         else {
 903                 write(fd, "-17", 3);
 904                 close(fd);
 905         }
 906
 907         /* setup signal handler pipe */
 908         retval = pipe(signal_pipe);
 909         if (retval < 0) {
 910                 err("error getting pipes: %s", strerror(errno));
 911                 goto exit;
 912         }
 913         retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
 914         if (retval < 0) {
 915                 err("error fcntl on read pipe: %s", strerror(errno));
 916                 goto exit;
 917         }
 918         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
 919         if (retval < 0) {
 920                 err("error fcntl on write pipe: %s", strerror(errno));
 921                 goto exit;
 922         }
 923
 924         /* set signal handlers */
 925         memset(&act, 0x00, sizeof(struct sigaction));
 926         act.sa_handler = (void (*)(int)) sig_handler;
 927         sigemptyset(&act.sa_mask);
 928         act.sa_flags = SA_RESTART;
 929         sigaction(SIGINT, &act, NULL);
 930         sigaction(SIGTERM, &act, NULL);
 931         sigaction(SIGCHLD, &act, NULL);
 932         sigaction(SIGHUP, &act, NULL);
 933
 934         /* watch rules directory */
 935         inotify_fd = inotify_init();
 936         if (inotify_fd > 0)
 937                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 938
 939         /* maximum limit of forked childs */
 940         value = getenv("UDEVD_MAX_CHILDS");
 941         if (value)
 942                 max_childs = strtoul(value, NULL, 10);
 943         else
 944                 max_childs = UDEVD_MAX_CHILDS;
 945         info("initialize max_childs to %u", max_childs);
 946
 947         /* start to throttle forking if maximum number of _running_ childs is reached */
 948         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 949         if (value)
 950                 max_childs_running = strtoull(value, NULL, 10);
 951         else
 952                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 953         info("initialize max_childs_running to %u", max_childs_running);
 954
 955         /* clear environment for forked event processes */
 956         clearenv();
 957
 958         /* export log_priority , as called programs may want to follow that setting */
 959         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 960         putenv(udev_log);
 961
 962         maxfd = udevd_sock;
 963         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
 964         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
 965         maxfd = UDEV_MAX(maxfd, inotify_fd);
 966
 967         while (!udev_exit) {
 968                 struct uevent_msg *msg;
 969                 int fdcount;
 970
 971                 FD_ZERO(&readfds);
 972                 FD_SET(signal_pipe[READ_END], &readfds);
 973                 FD_SET(udevd_sock, &readfds);
 974                 FD_SET(uevent_netlink_sock, &readfds);
 975                 if (inotify_fd > 0)
 976                         FD_SET(inotify_fd, &readfds);
 977
 978                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
 979                 if (fdcount < 0) {
 980                         if (errno != EINTR)
 981                                 err("error in select: %s", strerror(errno));
 982                         continue;
 983                 }
 984
 985                 /* get user socket message */
 986                 if (FD_ISSET(udevd_sock, &readfds)) {
 987                         msg = get_udevd_msg();
 988                         if (msg)
 989                                 msg_queue_insert(msg);
 990                 }
 991
 992                 /* get kernel netlink message */
 993                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
 994                         msg = get_netlink_msg();
 995                         if (msg)
 996                                 msg_queue_insert(msg);
 997                 }
 998
 999                 /* received a signal, clear our notification pipe */
1000                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1001                         char buf[256];
1002
1003                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1004                 }
1005
1006                 /* rules directory inotify watch */
1007                 if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
1008                         int nbytes;
1009
1010                         /* discard all possible events, we can just reload the config */
1011                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1012                                 char *buf;
1013
1014                                 reload_config = 1;
1015                                 buf = malloc(nbytes);
1016                                 if (!buf) {
1017                                         err("error getting buffer for inotify, disable watching");
1018                                         close(inotify_fd);
1019                                         inotify_fd = -1;
1020                                 }
1021                                 read(inotify_fd, buf, nbytes);
1022                                 free(buf);
1023                         }
1024                 }
1025
1026                 /* rules changed, set by inotify or a signal*/
1027                 if (reload_config) {
1028                         reload_config = 0;
1029                         udev_rules_cleanup(&rules);
1030                         udev_rules_init(&rules, 1);
1031                 }
1032
1033                 /* forked child has returned */
1034                 if (sigchilds_waiting) {
1035                         sigchilds_waiting = 0;
1036                         reap_sigchilds();
1037                 }
1038
1039                 if (run_exec_q) {
1040                         run_exec_q = 0;
1041                         if (!stop_exec_q)
1042                                 msg_queue_manager();
1043                 }
1044         }
1045
1046 exit:
1047         udev_rules_cleanup(&rules);
1048         sysfs_cleanup();
1049
1050         if (signal_pipe[READ_END] > 0)
1051                 close(signal_pipe[READ_END]);
1052         if (signal_pipe[WRITE_END] > 0)
1053                 close(signal_pipe[WRITE_END]);
1054
1055         if (udevd_sock > 0)
1056                 close(udevd_sock);
1057         if (inotify_fd > 0)
1058                 close(inotify_fd);
1059         if (uevent_netlink_sock > 0)
1060                 close(uevent_netlink_sock);
1061
1062         logging_close();
1063
1064         return rc;
1065 }