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