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 <sys/select.h>
  35 #include <sys/wait.h>
  36 #include <sys/time.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/sysinfo.h>
  41 #include <sys/stat.h>
  42 #include <sys/ioctl.h>
  43 #include <linux/types.h>
  44 #include <linux/netlink.h>
  45
  46 #include "list.h"
  47 #include "udev_libc_wrapper.h"
  48 #include "udev.h"
  49 #include "udev_version.h"
  50 #include "udev_rules.h"
  51 #include "udev_utils.h"
  52 #include "udevd.h"
  53 #include "logging.h"
  54
  55 /* global variables*/
  56 struct udev_rules rules;
  57 static int udevd_sock;
  58 static int uevent_netlink_sock;
  59 static int inotify_fd;
  60 static pid_t sid;
  61
  62 static int signal_pipe[2] = {-1, -1};
  63 static volatile int sigchilds_waiting;
  64 static volatile int run_msg_q;
  65 static volatile int udev_exit;
  66 static volatile int reload_config;
  67 static int init_phase = 1;
  68 static int run_exec_q;
  69 static int stop_exec_q;
  70 static int event_timeout;
  71 static int max_childs;
  72 static int max_childs_running;
  73 static unsigned long long expected_seqnum;
  74 static char udev_log[32];
  75
  76 static LIST_HEAD(msg_list);
  77 static LIST_HEAD(exec_list);
  78 static LIST_HEAD(running_list);
  79
  80
  81 #ifdef USE_LOG
  82 void log_message(int priority, const char *format, ...)
  83 {
  84         va_list args;
  85
  86         if (priority > udev_log_priority)
  87                 return;
  88
  89         va_start(args, format);
  90         vsyslog(priority, format, args);
  91         va_end(args);
  92 }
  93 #endif
  94
  95 static void msg_dump_queue(void)
  96 {
  97 #ifdef DEBUG
  98         struct uevent_msg *msg;
  99
 100         list_for_each_entry(msg, &msg_list, node)
 101                 dbg("sequence %llu in queue", msg->seqnum);
 102 #endif
 103 }
 104
 105 static void msg_queue_delete(struct uevent_msg *msg)
 106 {
 107         list_del(&msg->node);
 108         free(msg);
 109 }
 110
 111 /* orders the message in the queue by sequence number */
 112 static void msg_queue_insert(struct uevent_msg *msg)
 113 {
 114         struct uevent_msg *loop_msg;
 115         struct sysinfo info;
 116
 117         if (msg->seqnum == 0) {
 118                 dbg("no SEQNUM, move straight to the exec queue");
 119                 list_add_tail(&msg->node, &exec_list);
 120                 run_exec_q = 1;
 121                 return;
 122         }
 123
 124         /* store timestamp of queuing */
 125         sysinfo(&info);
 126         msg->queue_time = info.uptime;
 127
 128         /* with the first event we provide a phase of shorter timeout */
 129         if (init_phase) {
 130                 static long init_time;
 131
 132                 if (init_time == 0)
 133                         init_time = info.uptime;
 134                 if (info.uptime - init_time >= UDEVD_INIT_TIME)
 135                         init_phase = 0;
 136         }
 137
 138         /* sort message by sequence number into list */
 139         list_for_each_entry_reverse(loop_msg, &msg_list, node) {
 140                 if (loop_msg->seqnum < msg->seqnum)
 141                         break;
 142
 143                 if (loop_msg->seqnum == msg->seqnum) {
 144                         dbg("ignoring duplicate message seq %llu", msg->seqnum);
 145                         free(msg);
 146                         return;
 147                 }
 148         }
 149         list_add(&msg->node, &loop_msg->node);
 150         info("seq %llu queued, '%s' '%s'", msg->seqnum, msg->action, msg->devpath);
 151
 152         /* run msg queue manager */
 153         run_msg_q = 1;
 154
 155         return;
 156 }
 157
 158 static void asmlinkage udev_event_sig_handler(int signum)
 159 {
 160         if (signum == SIGALRM)
 161                 exit(1);
 162 }
 163
 164 static int udev_event_process(struct uevent_msg *msg)
 165 {
 166         struct sigaction act;
 167         struct udevice udev;
 168         struct name_entry *name_loop;
 169         int i;
 170         int retval;
 171
 172         /* set signal handlers */
 173         memset(&act, 0x00, sizeof(act));
 174         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 175         sigemptyset (&act.sa_mask);
 176         act.sa_flags = 0;
 177         sigaction(SIGALRM, &act, NULL);
 178
 179         /* trigger timeout to prevent hanging processes */
 180         alarm(UDEV_ALARM_TIMEOUT);
 181
 182         /* reconstruct env from message */
 183         for (i = 0; msg->envp[i]; i++)
 184                 putenv(msg->envp[i]);
 185
 186         udev_init_device(&udev, msg->devpath, msg->subsystem, msg->action);
 187         retval = udev_process_event(&rules, &udev);
 188
 189         /* run programs collected by RUN-key*/
 190         if (!retval) {
 191                 list_for_each_entry(name_loop, &udev.run_list, node) {
 192                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 193                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
 194                         else
 195                                 run_program(name_loop->name, udev.subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO));
 196                 }
 197         }
 198
 199         udev_cleanup_device(&udev);
 200
 201         return 0;
 202 }
 203
 204 /* runs event and removes event from run queue when finished */
 205 static void udev_event_run(struct uevent_msg *msg)
 206 {
 207         pid_t pid;
 208         struct sysinfo info;
 209
 210         pid = fork();
 211         switch (pid) {
 212         case 0:
 213                 /* child */
 214                 close(uevent_netlink_sock);
 215                 close(udevd_sock);
 216                 if (inotify_fd > 0)
 217                         close(inotify_fd);
 218                 close(signal_pipe[READ_END]);
 219                 close(signal_pipe[WRITE_END]);
 220                 logging_close();
 221
 222                 logging_init("udevd-event");
 223                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 224                 udev_event_process(msg);
 225                 info("seq %llu finished", msg->seqnum);
 226
 227                 logging_close();
 228                 exit(0);
 229         case -1:
 230                 err("fork of child failed");
 231                 msg_queue_delete(msg);
 232                 break;
 233         default:
 234                 /* get SIGCHLD in main loop */
 235                 sysinfo(&info);
 236                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 237                      msg->seqnum, pid,  msg->action, msg->subsystem, info.uptime - msg->queue_time);
 238                 msg->pid = pid;
 239         }
 240 }
 241
 242 static int running_processes(void)
 243 {
 244         int f;
 245         static char buf[4096];
 246         int len;
 247         int running;
 248         const char *pos;
 249
 250         f = open("/proc/stat", O_RDONLY);
 251         if (f == -1)
 252                 return -1;
 253
 254         len = read(f, buf, sizeof(buf)-1);
 255         close(f);
 256
 257         if (len <= 0)
 258                 return -1;
 259         else
 260                 buf[len] = '\0';
 261
 262         pos = strstr(buf, "procs_running ");
 263         if (pos == NULL)
 264                 return -1;
 265
 266         if (sscanf(pos, "procs_running %u", &running) != 1)
 267                 return -1;
 268
 269         return running;
 270 }
 271
 272 /* return the number of process es in our session, count only until limit */
 273 static int running_processes_in_session(pid_t session, int limit)
 274 {
 275         DIR *dir;
 276         struct dirent *dent;
 277         int running = 0;
 278
 279         dir = opendir("/proc");
 280         if (!dir)
 281                 return -1;
 282
 283         /* read process info from /proc */
 284         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 285                 int f;
 286                 char procdir[64];
 287                 char line[256];
 288                 const char *pos;
 289                 char state;
 290                 pid_t ppid, pgrp, sess;
 291                 int len;
 292
 293                 if (!isdigit(dent->d_name[0]))
 294                         continue;
 295
 296                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 297                 procdir[sizeof(procdir)-1] = '\0';
 298
 299                 f = open(procdir, O_RDONLY);
 300                 if (f == -1)
 301                         continue;
 302
 303                 len = read(f, line, sizeof(line)-1);
 304                 close(f);
 305
 306                 if (len <= 0)
 307                         continue;
 308                 else
 309                         line[len] = '\0';
 310
 311                 /* skip ugly program name */
 312                 pos = strrchr(line, ')') + 2;
 313                 if (pos == NULL)
 314                         continue;
 315
 316                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 317                         continue;
 318
 319                 /* count only processes in our session */
 320                 if (sess != session)
 321                         continue;
 322
 323                 /* count only running, no sleeping processes */
 324                 if (state != 'R')
 325                         continue;
 326
 327                 running++;
 328                 if (limit > 0 && running >= limit)
 329                         break;
 330         }
 331         closedir(dir);
 332
 333         return running;
 334 }
 335
 336 static int compare_devpath(const char *running, const char *waiting)
 337 {
 338         int i;
 339
 340         for (i = 0; i < PATH_SIZE; i++) {
 341                 /* identical device event found */
 342                 if (running[i] == '\0' && waiting[i] == '\0')
 343                         return 1;
 344
 345                 /* parent device event found */
 346                 if (running[i] == '\0' && waiting[i] == '/')
 347                         return 2;
 348
 349                 /* child device event found */
 350                 if (running[i] == '/' && waiting[i] == '\0')
 351                         return 3;
 352
 353                 /* no matching event */
 354                 if (running[i] != waiting[i])
 355                         break;
 356         }
 357
 358         return 0;
 359 }
 360
 361 /* returns still running task for the same device, its parent or its physical device */
 362 static int running_with_devpath(struct uevent_msg *msg, int limit)
 363 {
 364         struct uevent_msg *loop_msg;
 365         int childs_count = 0;
 366
 367         if (msg->devpath == NULL)
 368                 return 0;
 369
 370         /* skip any events with a timeout set */
 371         if (msg->timeout != 0)
 372                 return 0;
 373
 374         list_for_each_entry(loop_msg, &running_list, node) {
 375                 if (limit && childs_count++ > limit) {
 376                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 377                         return 1;
 378                 }
 379                 if (loop_msg->devpath == NULL)
 380                         continue;
 381
 382                 /* return running parent/child device event */
 383                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 384                         dbg("%llu, child device event still running %llu (%s)",
 385                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 386                         return 2;
 387                 }
 388
 389                 /* return running physical device event */
 390                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 391                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 392                                 dbg("%llu, physical device event still running %llu (%s)",
 393                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 394                                 return 3;
 395                         }
 396         }
 397
 398         return 0;
 399 }
 400
 401 /* exec queue management routine executes the events and serializes events in the same sequence */
 402 static void exec_queue_manager(void)
 403 {
 404         struct uevent_msg *loop_msg;
 405         struct uevent_msg *tmp_msg;
 406         int running;
 407
 408         if (list_empty(&exec_list))
 409                 return;
 410
 411         running = running_processes();
 412         dbg("%d processes runnning on system", running);
 413         if (running < 0)
 414                 running = max_childs_running;
 415
 416         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 417                 /* check running processes in our session and possibly throttle */
 418                 if (running >= max_childs_running) {
 419                         running = running_processes_in_session(sid, max_childs_running+10);
 420                         dbg("at least %d processes running in session", running);
 421                         if (running >= max_childs_running) {
 422                                 dbg("delay seq %llu, cause too many processes already running",
 423                                     loop_msg->seqnum);
 424                                 return;
 425                         }
 426                 }
 427
 428                 if (running_with_devpath(loop_msg, max_childs) == 0) {
 429                         /* move event to run list */
 430                         list_move_tail(&loop_msg->node, &running_list);
 431                         udev_event_run(loop_msg);
 432                         running++;
 433                         dbg("moved seq %llu to running list", loop_msg->seqnum);
 434                 } else
 435                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 436         }
 437 }
 438
 439 static void msg_move_exec(struct uevent_msg *msg)
 440 {
 441         list_move_tail(&msg->node, &exec_list);
 442         run_exec_q = 1;
 443         expected_seqnum = msg->seqnum+1;
 444         dbg("moved seq %llu to exec, next expected is %llu",
 445                 msg->seqnum, expected_seqnum);
 446 }
 447
 448 /* msg queue management routine handles the timeouts and dispatches the events */
 449 static void msg_queue_manager(void)
 450 {
 451         struct uevent_msg *loop_msg;
 452         struct uevent_msg *tmp_msg;
 453         struct sysinfo info;
 454         long msg_age = 0;
 455         int timeout = event_timeout;
 456
 457         dbg("msg queue manager, next expected is %llu", expected_seqnum);
 458 recheck:
 459         sysinfo(&info);
 460         list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, node) {
 461                 /* move event with expected sequence to the exec list */
 462                 if (loop_msg->seqnum == expected_seqnum) {
 463                         msg_move_exec(loop_msg);
 464                         continue;
 465                 }
 466
 467                 /* limit timeout during initialization phase */
 468                 if (init_phase) {
 469                         if (timeout > UDEVD_INIT_EVENT_TIMEOUT)
 470                                 timeout = UDEVD_INIT_EVENT_TIMEOUT;
 471                         dbg("initialization phase, timeout %i seconds", timeout);
 472                 }
 473
 474                 /* move event with expired timeout to the exec list */
 475                 msg_age = info.uptime - loop_msg->queue_time;
 476                 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
 477                 if (msg_age >= timeout) {
 478                         msg_move_exec(loop_msg);
 479                         goto recheck;
 480                 } else
 481                         break;
 482         }
 483
 484         msg_dump_queue();
 485
 486         /* set timeout for remaining queued events */
 487         if (!list_empty(&msg_list)) {
 488                 struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
 489                 info("next event expires in %li seconds", timeout - msg_age);
 490                 setitimer(ITIMER_REAL, &itv, NULL);
 491         }
 492 }
 493
 494 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 495 {
 496         int bufpos;
 497         int i;
 498         struct uevent_msg *msg;
 499         int major = 0;
 500         int minor = 0;
 501
 502         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 503         if (msg == NULL)
 504                 return NULL;
 505         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 506
 507         /* copy environment buffer and reconstruct envp */
 508         memcpy(msg->envbuf, buf, buf_size);
 509         bufpos = 0;
 510         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 511                 int keylen;
 512                 char *key;
 513
 514                 key = &msg->envbuf[bufpos];
 515                 keylen = strlen(key);
 516                 msg->envp[i] = key;
 517                 bufpos += keylen + 1;
 518                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 519
 520                 /* remember some keys for further processing */
 521                 if (strncmp(key, "ACTION=", 7) == 0)
 522                         msg->action = &key[7];
 523                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 524                         msg->devpath = &key[8];
 525                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 526                         msg->subsystem = &key[10];
 527                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 528                         msg->seqnum = strtoull(&key[7], NULL, 10);
 529                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 530                         msg->physdevpath = &key[12];
 531                 else if (strncmp(key, "MAJOR=", 6) == 0)
 532                         major = strtoull(&key[6], NULL, 10);
 533                 else if (strncmp(key, "MINOR=", 6) == 0)
 534                         minor = strtoull(&key[6], NULL, 10);
 535                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 536                         msg->timeout = strtoull(&key[8], NULL, 10);
 537         }
 538         msg->devt = makedev(major, minor);
 539         msg->envp[i++] = "UDEVD_EVENT=1";
 540         msg->envp[i] = NULL;
 541
 542         return msg;
 543 }
 544
 545 /* receive the udevd message from userspace */
 546 static struct uevent_msg *get_udevd_msg(void)
 547 {
 548         static struct udevd_msg usend_msg;
 549         struct uevent_msg *msg;
 550         ssize_t size;
 551         struct msghdr smsg;
 552         struct cmsghdr *cmsg;
 553         struct iovec iov;
 554         struct ucred *cred;
 555         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 556         int envbuf_size;
 557         int *intval;
 558
 559         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 560         iov.iov_base = &usend_msg;
 561         iov.iov_len = sizeof(struct udevd_msg);
 562
 563         memset(&smsg, 0x00, sizeof(struct msghdr));
 564         smsg.msg_iov = &iov;
 565         smsg.msg_iovlen = 1;
 566         smsg.msg_control = cred_msg;
 567         smsg.msg_controllen = sizeof(cred_msg);
 568
 569         size = recvmsg(udevd_sock, &smsg, 0);
 570         if (size <  0) {
 571                 if (errno != EINTR)
 572                         err("unable to receive udevd message");
 573                 return NULL;
 574         }
 575         cmsg = CMSG_FIRSTHDR(&smsg);
 576         cred = (struct ucred *) CMSG_DATA(cmsg);
 577
 578         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 579                 err("no sender credentials received, message ignored");
 580                 return NULL;
 581         }
 582
 583         if (cred->uid != 0) {
 584                 err("sender uid=%i, message ignored", cred->uid);
 585                 return NULL;
 586         }
 587
 588         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 589                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 590                 return NULL;
 591         }
 592
 593         switch (usend_msg.type) {
 594         case UDEVD_UEVENT_UDEVSEND:
 595         case UDEVD_UEVENT_INITSEND:
 596                 info("udevd event message received");
 597                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 598                 dbg("envbuf_size=%i", envbuf_size);
 599                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 600                 if (msg == NULL)
 601                         return NULL;
 602                 msg->type = usend_msg.type;
 603                 return msg;
 604         case UDEVD_STOP_EXEC_QUEUE:
 605                 info("udevd message (STOP_EXEC_QUEUE) received");
 606                 stop_exec_q = 1;
 607                 break;
 608         case UDEVD_START_EXEC_QUEUE:
 609                 info("udevd message (START_EXEC_QUEUE) received");
 610                 stop_exec_q = 0;
 611                 exec_queue_manager();
 612                 break;
 613         case UDEVD_SET_LOG_LEVEL:
 614                 intval = (int *) usend_msg.envbuf;
 615                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 616                 udev_log_priority = *intval;
 617                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 618                 putenv(udev_log);
 619                 break;
 620         case UDEVD_SET_MAX_CHILDS:
 621                 intval = (int *) usend_msg.envbuf;
 622                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 623                 max_childs = *intval;
 624                 break;
 625         case UDEVD_RELOAD_RULES:
 626                 info("udevd message (RELOAD_RULES) received");
 627                 reload_config = 1;
 628                 break;
 629         default:
 630                 dbg("unknown message type");
 631         }
 632         return NULL;
 633 }
 634
 635 /* receive the kernel user event message and do some sanity checks */
 636 static struct uevent_msg *get_netlink_msg(void)
 637 {
 638         struct uevent_msg *msg;
 639         int bufpos;
 640         ssize_t size;
 641         static char buffer[UEVENT_BUFFER_SIZE + 512];
 642         char *pos;
 643
 644         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 645         if (size <  0) {
 646                 if (errno != EINTR)
 647                         err("unable to receive udevd message");
 648                 return NULL;
 649         }
 650
 651         if ((size_t)size > sizeof(buffer)-1)
 652                 size = sizeof(buffer)-1;
 653         buffer[size] = '\0';
 654         dbg("uevent_size=%zi", size);
 655
 656         /* start of event payload */
 657         bufpos = strlen(buffer)+1;
 658         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 659         if (msg == NULL)
 660                 return NULL;
 661         msg->type = UDEVD_UEVENT_NETLINK;
 662
 663         /* validate message */
 664         pos = strchr(buffer, '@');
 665         if (pos == NULL) {
 666                 err("invalid uevent '%s'", buffer);
 667                 free(msg);
 668                 return NULL;
 669         }
 670         pos[0] = '\0';
 671
 672         if (msg->action == NULL) {
 673                 info("no ACTION in payload found, skip event '%s'", buffer);
 674                 free(msg);
 675                 return NULL;
 676         }
 677
 678         if (strcmp(msg->action, buffer) != 0) {
 679                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 680                 free(msg);
 681                 return NULL;
 682         }
 683
 684         return msg;
 685 }
 686
 687 static void asmlinkage sig_handler(int signum)
 688 {
 689         switch (signum) {
 690                 case SIGINT:
 691                 case SIGTERM:
 692                         udev_exit = 1;
 693                         break;
 694                 case SIGALRM:
 695                         /* set flag, then write to pipe if needed */
 696                         run_msg_q = 1;
 697                         break;
 698                 case SIGCHLD:
 699                         /* set flag, then write to pipe if needed */
 700                         sigchilds_waiting = 1;
 701                         break;
 702                 case SIGHUP:
 703                         reload_config = 1;
 704                         break;
 705         }
 706
 707         /* write to pipe, which will wakeup select() in our mainloop */
 708         write(signal_pipe[WRITE_END], "", 1);
 709 }
 710
 711 static void udev_done(int pid)
 712 {
 713         /* find msg associated with pid and delete it */
 714         struct uevent_msg *msg;
 715         struct sysinfo info;
 716
 717         list_for_each_entry(msg, &running_list, node) {
 718                 if (msg->pid == pid) {
 719                         sysinfo(&info);
 720                         if (msg->queue_time)
 721                                 info("seq %llu, pid [%d] exit, %ld seconds old", msg->seqnum, msg->pid, info.uptime - msg->queue_time);
 722                         else
 723                                 info("seq 0, pid [%d] exit", msg->pid);
 724                         msg_queue_delete(msg);
 725
 726                         /* we want to run the exec queue manager since there may
 727                          * be events waiting with the devpath of the one that
 728                          * just finished
 729                          */
 730                         run_exec_q = 1;
 731                         return;
 732                 }
 733         }
 734 }
 735
 736 static void reap_sigchilds(void)
 737 {
 738         pid_t pid;
 739
 740         while (1) {
 741                 pid = waitpid(-1, NULL, WNOHANG);
 742                 if (pid <= 0)
 743                         break;
 744                 udev_done(pid);
 745         }
 746 }
 747
 748 static int init_udevd_socket(void)
 749 {
 750         struct sockaddr_un saddr;
 751         const int buffersize = 16 * 1024 * 1024;
 752         socklen_t addrlen;
 753         const int feature_on = 1;
 754         int retval;
 755
 756         memset(&saddr, 0x00, sizeof(saddr));
 757         saddr.sun_family = AF_LOCAL;
 758         /* use abstract namespace for socket path */
 759         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 760         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 761
 762         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 763         if (udevd_sock == -1) {
 764                 err("error getting socket, %s", strerror(errno));
 765                 return -1;
 766         }
 767
 768         /* set receive buffersize */
 769         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 770
 771         /* the bind takes care of ensuring only one copy running */
 772         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 773         if (retval < 0) {
 774                 err("bind failed, %s", strerror(errno));
 775                 return -1;
 776         }
 777
 778         /* enable receiving of the sender credentials */
 779         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 780
 781         return 0;
 782 }
 783
 784 static int init_uevent_netlink_sock(void)
 785 {
 786         struct sockaddr_nl snl;
 787         const int buffersize = 16 * 1024 * 1024;
 788         int retval;
 789
 790         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 791         snl.nl_family = AF_NETLINK;
 792         snl.nl_pid = getpid();
 793         snl.nl_groups = 0xffffffff;
 794
 795         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 796         if (uevent_netlink_sock == -1) {
 797                 err("error getting socket, %s", strerror(errno));
 798                 return -1;
 799         }
 800
 801         /* set receive buffersize */
 802         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 803
 804         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 805         if (retval < 0) {
 806                 err("bind failed, %s", strerror(errno));
 807                 close(uevent_netlink_sock);
 808                 uevent_netlink_sock = -1;
 809                 return -1;
 810         }
 811         return 0;
 812 }
 813
 814 int main(int argc, char *argv[], char *envp[])
 815 {
 816         int retval;
 817         int devnull;
 818         struct sigaction act;
 819         fd_set readfds;
 820         const char *value;
 821         int uevent_netlink_active = 0;
 822         int daemonize = 0;
 823         int i;
 824         int rc = 0;
 825
 826         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 827         devnull = open("/dev/null", O_RDWR);
 828         if (devnull >= 0) {
 829                 if (devnull != STDIN_FILENO)
 830                         dup2(devnull, STDIN_FILENO);
 831                 if (devnull != STDOUT_FILENO)
 832                         dup2(devnull, STDOUT_FILENO);
 833                 if (devnull != STDERR_FILENO)
 834                         dup2(devnull, STDERR_FILENO);
 835                 if (devnull > STDERR_FILENO)
 836                         close(devnull);
 837         }
 838
 839         logging_init("udevd");
 840         if (devnull < 0)
 841                 err("fatal, could not open /dev/null");
 842
 843         udev_init_config();
 844         dbg("version %s", UDEV_VERSION);
 845
 846         if (getuid() != 0) {
 847                 err("need to be root, exit");
 848                 goto exit;
 849         }
 850
 851         /* parse commandline options */
 852         for (i = 1 ; i < argc; i++) {
 853                 char *arg = argv[i];
 854                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 855                         info("will daemonize");
 856                         daemonize = 1;
 857                 }
 858                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 859                         info("will not execute events until START_EXEC_QUEUE is received");
 860                         stop_exec_q = 1;
 861                 }
 862         }
 863
 864         /* init sockets to receive events */
 865         if (init_udevd_socket() < 0) {
 866                 if (errno == EADDRINUSE) {
 867                         dbg("another udevd running, exit");
 868                         rc = 1;
 869                 } else {
 870                         dbg("error initializing udevd socket: %s", strerror(errno));
 871                         rc = 2;
 872                 }
 873                 goto exit;
 874         }
 875
 876         if (init_uevent_netlink_sock() < 0) {
 877                 err("uevent socket not available");
 878                 rc = 3;
 879                 goto exit;
 880         }
 881
 882         /* parse the rules and keep it in memory */
 883         udev_rules_init(&rules, 0, 1);
 884
 885         if (daemonize) {
 886                 pid_t pid;
 887
 888                 pid = fork();
 889                 switch (pid) {
 890                 case 0:
 891                         dbg("daemonized fork running");
 892
 893                         /* become session leader */
 894                         sid = setsid();
 895                         dbg("our session is %d", sid);
 896
 897                         chdir("/");
 898                         umask(umask(077) | 022);
 899                         break;
 900                 case -1:
 901                         err("fork of daemon failed");
 902                         rc = 4;
 903                         goto exit;
 904                 default:
 905                         dbg("child [%u] running, parent exits", pid);
 906                         goto exit;
 907                 }
 908         }
 909
 910         /* set a reasonable scheduling priority for the daemon */
 911         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 912
 913         /* setup signal handler pipe */
 914         retval = pipe(signal_pipe);
 915         if (retval < 0) {
 916                 err("error getting pipes: %s", strerror(errno));
 917                 goto exit;
 918         }
 919         retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
 920         if (retval < 0) {
 921                 err("error fcntl on read pipe: %s", strerror(errno));
 922                 goto exit;
 923         }
 924         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
 925         if (retval < 0) {
 926                 err("error fcntl on write pipe: %s", strerror(errno));
 927                 goto exit;
 928         }
 929
 930         /* set signal handlers */
 931         memset(&act, 0x00, sizeof(struct sigaction));
 932         act.sa_handler = (void (*)(int)) sig_handler;
 933         sigemptyset(&act.sa_mask);
 934         act.sa_flags = SA_RESTART;
 935         sigaction(SIGINT, &act, NULL);
 936         sigaction(SIGTERM, &act, NULL);
 937         sigaction(SIGALRM, &act, NULL);
 938         sigaction(SIGCHLD, &act, NULL);
 939         sigaction(SIGHUP, &act, NULL);
 940
 941         /* watch rules directory */
 942         inotify_fd = inotify_init();
 943         if (inotify_fd > 0)
 944                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 945
 946         /* init of expected_seqnum value */
 947         value = getenv("UDEVD_EXPECTED_SEQNUM");
 948         if (value) {
 949                 expected_seqnum = strtoull(value, NULL, 10);
 950                 info("initialize expected_seqnum to %llu", expected_seqnum);
 951         }
 952
 953         /* timeout to wait for missing events */
 954         value = getenv("UDEVD_EVENT_TIMEOUT");
 955         if (value)
 956                 event_timeout = strtoul(value, NULL, 10);
 957         else
 958                 event_timeout = UDEVD_EVENT_TIMEOUT;
 959         info("initialize event_timeout to %u", event_timeout);
 960
 961         /* maximum limit of forked childs */
 962         value = getenv("UDEVD_MAX_CHILDS");
 963         if (value)
 964                 max_childs = strtoul(value, NULL, 10);
 965         else
 966                 max_childs = UDEVD_MAX_CHILDS;
 967         info("initialize max_childs to %u", max_childs);
 968
 969         /* start to throttle forking if maximum number of _running_ childs is reached */
 970         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 971         if (value)
 972                 max_childs_running = strtoull(value, NULL, 10);
 973         else
 974                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 975         info("initialize max_childs_running to %u", max_childs_running);
 976
 977         /* clear environment for forked event processes */
 978         clearenv();
 979
 980         /* export log_priority , as called programs may want to follow that setting */
 981         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 982         putenv(udev_log);
 983
 984         while (!udev_exit) {
 985                 struct uevent_msg *msg;
 986                 int fdcount;
 987
 988                 FD_ZERO(&readfds);
 989                 FD_SET(signal_pipe[READ_END], &readfds);
 990                 FD_SET(udevd_sock, &readfds);
 991                 FD_SET(uevent_netlink_sock, &readfds);
 992                 if (inotify_fd > 0)
 993                         FD_SET(inotify_fd, &readfds);
 994
 995                 fdcount = select(UDEV_MAX(uevent_netlink_sock, inotify_fd)+1, &readfds, NULL, NULL, NULL);
 996                 if (fdcount < 0) {
 997                         if (errno != EINTR)
 998                                 dbg("error in select: %s", strerror(errno));
 999                         continue;
1000                 }
1001
1002                 /* get user socket message */
1003                 if (FD_ISSET(udevd_sock, &readfds)) {
1004                         msg = get_udevd_msg();
1005                         if (msg) {
1006                                 /* discard kernel messages if netlink is active */
1007                                 if (uevent_netlink_active && msg->type == UDEVD_UEVENT_UDEVSEND && msg->seqnum != 0) {
1008                                         info("skip uevent_helper message with SEQNUM, netlink is active");
1009                                         free(msg);
1010                                 } else
1011                                         msg_queue_insert(msg);
1012                         }
1013                 }
1014
1015                 /* get kernel netlink message */
1016                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1017                         msg = get_netlink_msg();
1018                         if (msg) {
1019                                 msg_queue_insert(msg);
1020                                 /* disable udevsend with first netlink message */
1021                                 if (!uevent_netlink_active) {
1022                                         info("uevent_nl message received, disable udevsend messages");
1023                                         uevent_netlink_active = 1;
1024                                 }
1025                         }
1026                 }
1027
1028                 /* received a signal, clear our notification pipe */
1029                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1030                         char buf[256];
1031
1032                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1033                 }
1034
1035                 /* rules directory inotify watch */
1036                 if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
1037                         int nbytes;
1038
1039                         /* discard all possible events, we can just reload the config */
1040                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1041                                 char *buf;
1042
1043                                 reload_config = 1;
1044                                 buf = malloc(nbytes);
1045                                 if (!buf) {
1046                                         err("error getting buffer for inotify, disable watching");
1047                                         close(inotify_fd);
1048                                         inotify_fd = -1;
1049                                 }
1050                                 read(inotify_fd, buf, nbytes);
1051                                 free(buf);
1052                         }
1053                 }
1054
1055                 /* rules changed, set by inotify or a signal*/
1056                 if (reload_config) {
1057                         reload_config = 0;
1058                         udev_rules_close(&rules);
1059                         udev_rules_init(&rules, 0, 1);
1060                 }
1061
1062                 /* forked child have returned */
1063                 if (sigchilds_waiting) {
1064                         sigchilds_waiting = 0;
1065                         reap_sigchilds();
1066                 }
1067
1068                 if (run_msg_q) {
1069                         run_msg_q = 0;
1070                         msg_queue_manager();
1071                 }
1072
1073                 if (run_exec_q) {
1074                          /* clean up running_list before calling exec_queue_manager() */
1075                         if (sigchilds_waiting) {
1076                                 sigchilds_waiting = 0;
1077                                 reap_sigchilds();
1078                         }
1079
1080                         run_exec_q = 0;
1081                         if (!stop_exec_q)
1082                                 exec_queue_manager();
1083                 }
1084         }
1085
1086 exit:
1087         udev_rules_close(&rules);
1088
1089         if (signal_pipe[READ_END] > 0)
1090                 close(signal_pipe[READ_END]);
1091         if (signal_pipe[WRITE_END] > 0)
1092                 close(signal_pipe[WRITE_END]);
1093
1094         if (udevd_sock > 0)
1095                 close(udevd_sock);
1096         if (inotify_fd > 0)
1097                 close(inotify_fd);
1098         if (uevent_netlink_sock > 0)
1099                 close(uevent_netlink_sock);
1100
1101         logging_close();
1102
1103         return rc;
1104 }