udevd.c

   1 /*
   2  * udevd.c - hotplug event 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 <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38 #include <sys/un.h>
  39 #include <sys/sysinfo.h>
  40 #include <sys/stat.h>
  41 #include <linux/netlink.h>
  42
  43 #include "list.h"
  44 #include "udev_libc_wrapper.h"
  45 #include "udev.h"
  46 #include "udev_version.h"
  47 #include "udev_utils.h"
  48 #include "udevd.h"
  49 #include "logging.h"
  50
  51 #ifndef NETLINK_KOBJECT_UEVENT
  52 #define NETLINK_KOBJECT_UEVENT 15
  53 #endif
  54
  55 /* global variables*/
  56 static int udevd_sock;
  57 static int uevent_netlink_sock;
  58 static pid_t sid;
  59
  60 static int pipefds[2];
  61 static volatile int sigchilds_waiting;
  62 static volatile int run_msg_q;
  63 static volatile int sig_flag;
  64 static int init_phase = 1;
  65 static int run_exec_q;
  66 static int stop_exec_q;
  67
  68 static LIST_HEAD(msg_list);
  69 static LIST_HEAD(exec_list);
  70 static LIST_HEAD(running_list);
  71
  72 static void exec_queue_manager(void);
  73 static void msg_queue_manager(void);
  74 static void user_sighandler(void);
  75 static void reap_sigchilds(void);
  76
  77 static char *udev_bin;
  78 static unsigned long long expected_seqnum;
  79 static int event_timeout;
  80 static int max_childs;
  81 static int max_childs_running;
  82
  83
  84 #ifdef USE_LOG
  85 void log_message (int priority, const char *format, ...)
  86 {
  87         va_list args;
  88
  89         if (priority > udev_log_priority)
  90                 return;
  91
  92         va_start(args, format);
  93         vsyslog(priority, format, args);
  94         va_end(args);
  95 }
  96 #endif
  97
  98 static void msg_dump_queue(void)
  99 {
 100 #ifdef DEBUG
 101         struct uevent_msg *msg;
 102
 103         list_for_each_entry(msg, &msg_list, node)
 104                 dbg("sequence %llu in queue", msg->seqnum);
 105 #endif
 106 }
 107
 108 static void msg_queue_delete(struct uevent_msg *msg)
 109 {
 110         list_del(&msg->node);
 111         free(msg);
 112 }
 113
 114 /* orders the message in the queue by sequence number */
 115 static void msg_queue_insert(struct uevent_msg *msg)
 116 {
 117         struct uevent_msg *loop_msg;
 118         struct sysinfo info;
 119
 120         if (msg->seqnum == 0) {
 121                 dbg("no SEQNUM, move straight to the exec queue");
 122                 list_add(&msg->node, &exec_list);
 123                 run_exec_q = 1;
 124                 return;
 125         }
 126
 127         /* store timestamp of queuing */
 128         sysinfo(&info);
 129         msg->queue_time = info.uptime;
 130
 131         /* with the first event we provide a phase of shorter timeout */
 132         if (init_phase) {
 133                 static long init_time;
 134
 135                 if (init_time == 0)
 136                         init_time = info.uptime;
 137                 if (info.uptime - init_time >= UDEVD_INIT_TIME)
 138                         init_phase = 0;
 139         }
 140
 141         /* don't delay messages with timeout set */
 142         if (msg->timeout) {
 143                 dbg("move seq %llu with timeout %u to exec queue", msg->seqnum, msg->timeout);
 144                 list_add(&msg->node, &exec_list);
 145                 run_exec_q = 1;
 146                 return;
 147         }
 148
 149         /* sort message by sequence number into list */
 150         list_for_each_entry_reverse(loop_msg, &msg_list, node) {
 151                 if (loop_msg->seqnum < msg->seqnum)
 152                         break;
 153
 154                 if (loop_msg->seqnum == msg->seqnum) {
 155                         dbg("ignoring duplicate message seq %llu", msg->seqnum);
 156                         free(msg);
 157                         return;
 158                 }
 159         }
 160         list_add(&msg->node, &loop_msg->node);
 161         info("seq %llu queued, devpath '%s'", msg->seqnum, msg->devpath);
 162
 163         /* run msg queue manager */
 164         run_msg_q = 1;
 165
 166         return;
 167 }
 168
 169 /* forks event and removes event from run queue when finished */
 170 static void execute_udev(struct uevent_msg *msg)
 171 {
 172         char *const argv[] = { "udev", msg->subsystem, NULL };
 173         pid_t pid;
 174         struct sysinfo info;
 175
 176         pid = fork();
 177         switch (pid) {
 178         case 0:
 179                 /* child */
 180                 if (uevent_netlink_sock != -1)
 181                         close(uevent_netlink_sock);
 182                 close(udevd_sock);
 183                 logging_close();
 184
 185                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 186                 execve(udev_bin, argv, msg->envp);
 187                 err("exec of child failed");
 188                 _exit(1);
 189                 break;
 190         case -1:
 191                 err("fork of child failed");
 192                 msg_queue_delete(msg);
 193                 break;
 194         default:
 195                 /* get SIGCHLD in main loop */
 196                 sysinfo(&info);
 197                 info("seq %llu forked, pid %d, %ld seconds old",
 198                      msg->seqnum, pid, info.uptime - msg->queue_time);
 199                 msg->pid = pid;
 200         }
 201 }
 202
 203 static int running_processes(void)
 204 {
 205         int f;
 206         static char buf[4096];
 207         int len;
 208         int running;
 209         const char *pos;
 210
 211         f = open("/proc/stat", O_RDONLY);
 212         if (f == -1)
 213                 return -1;
 214
 215         len = read(f, buf, sizeof(buf));
 216         close(f);
 217
 218         if (len <= 0)
 219                 return -1;
 220         else
 221                 buf[len] = '\0';
 222
 223         pos = strstr(buf, "procs_running ");
 224         if (pos == NULL)
 225                 return -1;
 226
 227         if (sscanf(pos, "procs_running %u", &running) != 1)
 228                 return -1;
 229
 230         return running;
 231 }
 232
 233 /* return the number of process es in our session, count only until limit */
 234 static int running_processes_in_session(pid_t session, int limit)
 235 {
 236         DIR *dir;
 237         struct dirent *dent;
 238         int running = 0;
 239
 240         dir = opendir("/proc");
 241         if (!dir)
 242                 return -1;
 243
 244         /* read process info from /proc */
 245         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 246                 int f;
 247                 char procdir[64];
 248                 char line[256];
 249                 const char *pos;
 250                 char state;
 251                 pid_t ppid, pgrp, sess;
 252                 int len;
 253
 254                 if (!isdigit(dent->d_name[0]))
 255                         continue;
 256
 257                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 258                 procdir[sizeof(procdir)-1] = '\0';
 259
 260                 f = open(procdir, O_RDONLY);
 261                 if (f == -1)
 262                         continue;
 263
 264                 len = read(f, line, sizeof(line));
 265                 close(f);
 266
 267                 if (len <= 0)
 268                         continue;
 269                 else
 270                         line[len] = '\0';
 271
 272                 /* skip ugly program name */
 273                 pos = strrchr(line, ')') + 2;
 274                 if (pos == NULL)
 275                         continue;
 276
 277                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 278                         continue;
 279
 280                 /* count only processes in our session */
 281                 if (sess != session)
 282                         continue;
 283
 284                 /* count only running, no sleeping processes */
 285                 if (state != 'R')
 286                         continue;
 287
 288                 running++;
 289                 if (limit > 0 && running >= limit)
 290                         break;
 291         }
 292         closedir(dir);
 293
 294         return running;
 295 }
 296
 297 static int compare_devpath(const char *running, const char *waiting)
 298 {
 299         int i;
 300
 301         for (i = 0; i < PATH_SIZE; i++) {
 302                 /* identical device event found */
 303                 if (running[i] == '\0' && waiting[i] == '\0')
 304                         return 1;
 305
 306                 /* parent device event found */
 307                 if (running[i] == '\0' && waiting[i] == '/')
 308                         return 2;
 309
 310                 /* child device event found */
 311                 if (running[i] == '/' && waiting[i] == '\0')
 312                         return 3;
 313
 314                 /* no matching event */
 315                 if (running[i] != waiting[i])
 316                         break;
 317         }
 318
 319         return 0;
 320 }
 321
 322 /* returns still running task for the same device, its parent or its physical device */
 323 static int running_with_devpath(struct uevent_msg *msg, int limit)
 324 {
 325         struct uevent_msg *loop_msg;
 326         int childs_count = 0;
 327
 328         if (msg->devpath == NULL)
 329                 return 0;
 330
 331         /* skip any events with a timeout set */
 332         if (msg->timeout != 0)
 333                 return 0;
 334
 335         list_for_each_entry(loop_msg, &running_list, node) {
 336                 if (limit && childs_count++ > limit) {
 337                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 338                         return 1;
 339                 }
 340                 if (loop_msg->devpath == NULL)
 341                         continue;
 342
 343                 /* return running parent/child device event */
 344                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 345                         dbg("%llu, child device event still running %llu (%s)",
 346                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 347                         return 2;
 348                 }
 349
 350                 /* return running physical device event */
 351                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 352                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 353                                 dbg("%llu, physical device event still running %llu (%s)",
 354                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 355                                 return 3;
 356                         }
 357         }
 358
 359         return 0;
 360 }
 361
 362 /* exec queue management routine executes the events and serializes events in the same sequence */
 363 static void exec_queue_manager(void)
 364 {
 365         struct uevent_msg *loop_msg;
 366         struct uevent_msg *tmp_msg;
 367         int running;
 368
 369         if (list_empty(&exec_list))
 370                 return;
 371
 372         running = running_processes();
 373         dbg("%d processes runnning on system", running);
 374         if (running < 0)
 375                 running = max_childs_running;
 376
 377         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 378                 /* check running processes in our session and possibly throttle */
 379                 if (running >= max_childs_running) {
 380                         running = running_processes_in_session(sid, max_childs_running+10);
 381                         dbg("at least %d processes running in session", running);
 382                         if (running >= max_childs_running) {
 383                                 dbg("delay seq %llu, cause too many processes already running",
 384                                     loop_msg->seqnum);
 385                                 return;
 386                         }
 387                 }
 388
 389                 if (running_with_devpath(loop_msg, max_childs) == 0) {
 390                         /* move event to run list */
 391                         list_move_tail(&loop_msg->node, &running_list);
 392                         execute_udev(loop_msg);
 393                         running++;
 394                         dbg("moved seq %llu to running list", loop_msg->seqnum);
 395                 } else
 396                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 397         }
 398 }
 399
 400 static void msg_move_exec(struct uevent_msg *msg)
 401 {
 402         list_move_tail(&msg->node, &exec_list);
 403         run_exec_q = 1;
 404         expected_seqnum = msg->seqnum+1;
 405         dbg("moved seq %llu to exec, next expected is %llu",
 406                 msg->seqnum, expected_seqnum);
 407 }
 408
 409 /* msg queue management routine handles the timeouts and dispatches the events */
 410 static void msg_queue_manager(void)
 411 {
 412         struct uevent_msg *loop_msg;
 413         struct uevent_msg *tmp_msg;
 414         struct sysinfo info;
 415         long msg_age = 0;
 416         int timeout = event_timeout;
 417
 418         dbg("msg queue manager, next expected is %llu", expected_seqnum);
 419 recheck:
 420         sysinfo(&info);
 421         list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, node) {
 422                 /* move event with expected sequence to the exec list */
 423                 if (loop_msg->seqnum == expected_seqnum) {
 424                         msg_move_exec(loop_msg);
 425                         continue;
 426                 }
 427
 428                 /* limit timeout during initialization phase */
 429                 if (init_phase) {
 430                         timeout = UDEVD_INIT_EVENT_TIMEOUT;
 431                         dbg("initialization phase, limit timeout to %i seconds", UDEVD_INIT_EVENT_TIMEOUT);
 432                 }
 433
 434                 /* move event with expired timeout to the exec list */
 435                 msg_age = info.uptime - loop_msg->queue_time;
 436                 dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
 437                 if (msg_age >= timeout) {
 438                         msg_move_exec(loop_msg);
 439                         goto recheck;
 440                 } else {
 441                         break;
 442                 }
 443         }
 444
 445         msg_dump_queue();
 446
 447         /* set timeout for remaining queued events */
 448         if (list_empty(&msg_list) == 0) {
 449                 struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
 450                 dbg("next event expires in %li seconds", timeout - msg_age);
 451                 setitimer(ITIMER_REAL, &itv, NULL);
 452         }
 453 }
 454
 455 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 456 {
 457         int bufpos;
 458         int i;
 459         struct uevent_msg *msg;
 460         int major = 0;
 461         int minor = 0;
 462
 463         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 464         if (msg == NULL)
 465                 return NULL;
 466         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 467
 468         /* copy environment buffer and reconstruct envp */
 469         memcpy(msg->envbuf, buf, buf_size);
 470         bufpos = 0;
 471         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 472                 int keylen;
 473                 char *key;
 474
 475                 key = &msg->envbuf[bufpos];
 476                 keylen = strlen(key);
 477                 msg->envp[i] = key;
 478                 bufpos += keylen + 1;
 479                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 480
 481                 /* remember some keys for further processing */
 482                 if (strncmp(key, "ACTION=", 7) == 0)
 483                         msg->action = &key[7];
 484                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 485                         msg->devpath = &key[8];
 486                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 487                         msg->subsystem = &key[10];
 488                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 489                         msg->seqnum = strtoull(&key[7], NULL, 10);
 490                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 491                         msg->physdevpath = &key[12];
 492                 else if (strncmp(key, "MAJOR=", 6) == 0)
 493                         major = strtoull(&key[6], NULL, 10);
 494                 else if (strncmp(key, "MINOR=", 6) == 0)
 495                         minor = strtoull(&key[6], NULL, 10);
 496                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 497                         msg->timeout = strtoull(&key[8], NULL, 10);
 498         }
 499         msg->devt = makedev(major, minor);
 500         msg->envp[i++] = "UDEVD_EVENT=1";
 501         msg->envp[i] = NULL;
 502
 503         return msg;
 504 }
 505
 506 /* receive the udevd message from userspace */
 507 static struct uevent_msg *get_udevd_msg(void)
 508 {
 509         static struct udevd_msg usend_msg;
 510         struct uevent_msg *msg;
 511         ssize_t size;
 512         struct msghdr smsg;
 513         struct cmsghdr *cmsg;
 514         struct iovec iov;
 515         struct ucred *cred;
 516         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 517         int envbuf_size;
 518         int *intval;
 519
 520         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 521         iov.iov_base = &usend_msg;
 522         iov.iov_len = sizeof(struct udevd_msg);
 523
 524         memset(&smsg, 0x00, sizeof(struct msghdr));
 525         smsg.msg_iov = &iov;
 526         smsg.msg_iovlen = 1;
 527         smsg.msg_control = cred_msg;
 528         smsg.msg_controllen = sizeof(cred_msg);
 529
 530         size = recvmsg(udevd_sock, &smsg, 0);
 531         if (size <  0) {
 532                 if (errno != EINTR)
 533                         dbg("unable to receive udevd message");
 534                 return NULL;
 535         }
 536         cmsg = CMSG_FIRSTHDR(&smsg);
 537         cred = (struct ucred *) CMSG_DATA(cmsg);
 538
 539         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 540                 info("no sender credentials received, message ignored");
 541                 return NULL;
 542         }
 543
 544         if (cred->uid != 0) {
 545                 info("sender uid=%i, message ignored", cred->uid);
 546                 return NULL;
 547         }
 548
 549         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 550                 info("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 551                 return NULL;
 552         }
 553
 554         switch (usend_msg.type) {
 555         case UDEVD_UEVENT_UDEVSEND:
 556         case UDEVD_UEVENT_INITSEND:
 557                 info("udevd event message received");
 558                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 559                 dbg("envbuf_size=%i", envbuf_size);
 560                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 561                 if (msg == NULL)
 562                         return NULL;
 563                 msg->type = usend_msg.type;
 564                 return msg;
 565         case UDEVD_STOP_EXEC_QUEUE:
 566                 info("udevd message (STOP_EXEC_QUEUE) received");
 567                 stop_exec_q = 1;
 568                 break;
 569         case UDEVD_START_EXEC_QUEUE:
 570                 info("udevd message (START_EXEC_QUEUE) received");
 571                 stop_exec_q = 0;
 572                 exec_queue_manager();
 573                 break;
 574         case UDEVD_SET_LOG_LEVEL:
 575                 intval = (int *) usend_msg.envbuf;
 576                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 577                 udev_log_priority = *intval;
 578                 break;
 579         case UDEVD_SET_MAX_CHILDS:
 580                 intval = (int *) usend_msg.envbuf;
 581                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 582                 max_childs = *intval;
 583                 break;
 584         default:
 585                 dbg("unknown message type");
 586         }
 587         return NULL;
 588 }
 589
 590 /* receive the kernel user event message and do some sanity checks */
 591 static struct uevent_msg *get_netlink_msg(void)
 592 {
 593         struct uevent_msg *msg;
 594         int bufpos;
 595         ssize_t size;
 596         static char buffer[UEVENT_BUFFER_SIZE + 512];
 597         char *pos;
 598
 599         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 600         if (size <  0) {
 601                 if (errno != EINTR)
 602                         dbg("unable to receive udevd message");
 603                 return NULL;
 604         }
 605
 606         if ((size_t)size > sizeof(buffer)-1)
 607                 size = sizeof(buffer)-1;
 608         buffer[size] = '\0';
 609         dbg("uevent_size=%zi", size);
 610
 611         /* start of event payload */
 612         bufpos = strlen(buffer)+1;
 613         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 614         if (msg == NULL)
 615                 return NULL;
 616         msg->type = UDEVD_UEVENT_NETLINK;
 617
 618         /* validate message */
 619         pos = strchr(buffer, '@');
 620         if (pos == NULL) {
 621                 dbg("invalid uevent '%s'", buffer);
 622                 free(msg);
 623                 return NULL;
 624         }
 625         pos[0] = '\0';
 626
 627         if (msg->action == NULL) {
 628                 dbg("no ACTION in payload found, skip event '%s'", buffer);
 629                 free(msg);
 630                 return NULL;
 631         }
 632
 633         if (strcmp(msg->action, buffer) != 0) {
 634                 dbg("ACTION in payload does not match uevent, skip event '%s'", buffer);
 635                 free(msg);
 636                 return NULL;
 637         }
 638
 639         return msg;
 640 }
 641
 642 static void asmlinkage sig_handler(int signum)
 643 {
 644         int rc;
 645
 646         switch (signum) {
 647                 case SIGINT:
 648                 case SIGTERM:
 649                         exit(20 + signum);
 650                         break;
 651                 case SIGALRM:
 652                         /* set flag, then write to pipe if needed */
 653                         run_msg_q = 1;
 654                         goto do_write;
 655                         break;
 656                 case SIGCHLD:
 657                         /* set flag, then write to pipe if needed */
 658                         sigchilds_waiting = 1;
 659                         goto do_write;
 660                         break;
 661         }
 662
 663 do_write:
 664         /* if pipe is empty, write to pipe to force select to return
 665          * immediately when it gets called
 666          */
 667         if (!sig_flag) {
 668                 rc = write(pipefds[1],&signum,sizeof(signum));
 669                 if (rc >= 0)
 670                         sig_flag = 1;
 671         }
 672 }
 673
 674 static void udev_done(int pid)
 675 {
 676         /* find msg associated with pid and delete it */
 677         struct uevent_msg *msg;
 678         struct sysinfo info;
 679
 680         list_for_each_entry(msg, &running_list, node) {
 681                 if (msg->pid == pid) {
 682                         sysinfo(&info);
 683                         info("seq %llu exit, %ld seconds old", msg->seqnum, info.uptime - msg->queue_time);
 684                         msg_queue_delete(msg);
 685
 686                         /* we want to run the exec queue manager since there may
 687                          * be events waiting with the devpath of the one that
 688                          * just finished
 689                          */
 690                         run_exec_q = 1;
 691                         return;
 692                 }
 693         }
 694 }
 695
 696 static void reap_sigchilds(void)
 697 {
 698         while(1) {
 699                 int pid = waitpid(-1, NULL, WNOHANG);
 700                 if ((pid == -1) || (pid == 0))
 701                         break;
 702                 udev_done(pid);
 703         }
 704 }
 705
 706 /* just read everything from the pipe and clear the flag,
 707  * the flags was set in the signal handler
 708  */
 709 static void user_sighandler(void)
 710 {
 711         int sig;
 712
 713         while(1) {
 714                 int rc = read(pipefds[0], &sig, sizeof(sig));
 715                 if (rc < 0)
 716                         break;
 717
 718                 sig_flag = 0;
 719         }
 720 }
 721
 722 static int init_udevd_socket(void)
 723 {
 724         struct sockaddr_un saddr;
 725         socklen_t addrlen;
 726         const int feature_on = 1;
 727         int retval;
 728
 729         memset(&saddr, 0x00, sizeof(saddr));
 730         saddr.sun_family = AF_LOCAL;
 731         /* use abstract namespace for socket path */
 732         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 733         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 734
 735         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 736         if (udevd_sock == -1) {
 737                 err("error getting socket, %s", strerror(errno));
 738                 return -1;
 739         }
 740
 741         /* the bind takes care of ensuring only one copy running */
 742         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 743         if (retval < 0) {
 744                 err("bind failed, %s", strerror(errno));
 745                 close(udevd_sock);
 746                 return -1;
 747         }
 748
 749         /* enable receiving of the sender credentials */
 750         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 751
 752         return 0;
 753 }
 754
 755 static int init_uevent_netlink_sock(void)
 756 {
 757         struct sockaddr_nl snl;
 758         int retval;
 759
 760         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 761         snl.nl_family = AF_NETLINK;
 762         snl.nl_pid = getpid();
 763         snl.nl_groups = 0xffffffff;
 764
 765         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 766         if (uevent_netlink_sock == -1) {
 767                 dbg("error getting socket, %s", strerror(errno));
 768                 return -1;
 769         }
 770
 771         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl,
 772                       sizeof(struct sockaddr_nl));
 773         if (retval < 0) {
 774                 dbg("bind failed, %s", strerror(errno));
 775                 close(uevent_netlink_sock);
 776                 uevent_netlink_sock = -1;
 777                 return -1;
 778         }
 779
 780         return 0;
 781 }
 782
 783 int main(int argc, char *argv[], char *envp[])
 784 {
 785         int maxsockplus;
 786         int retval;
 787         int fd;
 788         struct sigaction act;
 789         fd_set readfds;
 790         const char *value;
 791         int uevent_netlink_active = 0;
 792         int daemonize = 0;
 793         int i;
 794
 795         logging_init("udevd");
 796         udev_init_config();
 797         dbg("version %s", UDEV_VERSION);
 798
 799         if (getuid() != 0) {
 800                 err("need to be root, exit");
 801                 goto exit;
 802         }
 803
 804         for (i = 1 ; i < argc; i++) {
 805                 char *arg = argv[i];
 806                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 807                         info("will daemonize");
 808                         daemonize = 1;
 809                 }
 810                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 811                         info("will not execute events until START_EXEC_QUEUE is received");
 812                         stop_exec_q = 1;
 813                 }
 814         }
 815         if (daemonize) {
 816                 pid_t pid;
 817
 818                 pid = fork();
 819                 switch (pid) {
 820                 case 0:
 821                         dbg("damonized fork running");
 822                         break;
 823                 case -1:
 824                         err("fork of daemon failed");
 825                         goto exit;
 826                 default:
 827                         logging_close();
 828                         exit(0);
 829                 }
 830         }
 831
 832         /* become session leader */
 833         sid = setsid();
 834         dbg("our session is %d", sid);
 835
 836         chdir("/");
 837         umask(umask(077) | 022);
 838
 839         /*set a reasonable scheduling priority for the daemon */
 840         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 841
 842         /* Set fds to dev/null */
 843         fd = open( "/dev/null", O_RDWR );
 844         if (fd >= 0)  {
 845                 dup2(fd, 0);
 846                 dup2(fd, 1);
 847                 dup2(fd, 2);
 848                 if (fd > 2)
 849                         close(fd);
 850         } else
 851                 err("error opening /dev/null %s", strerror(errno));
 852
 853         /* setup signal handler pipe */
 854         retval = pipe(pipefds);
 855         if (retval < 0) {
 856                 err("error getting pipes: %s", strerror(errno));
 857                 goto exit;
 858         }
 859
 860         retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
 861         if (retval < 0) {
 862                 err("error fcntl on read pipe: %s", strerror(errno));
 863                 goto exit;
 864         }
 865         retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
 866         if (retval < 0)
 867                 err("error fcntl on read pipe: %s", strerror(errno));
 868
 869         retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
 870         if (retval < 0) {
 871                 err("error fcntl on write pipe: %s", strerror(errno));
 872                 goto exit;
 873         }
 874         retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
 875         if (retval < 0)
 876                 err("error fcntl on write pipe: %s", strerror(errno));
 877
 878         /* set signal handlers */
 879         memset(&act, 0x00, sizeof(struct sigaction));
 880         act.sa_handler = (void (*)(int)) sig_handler;
 881         sigemptyset(&act.sa_mask);
 882         act.sa_flags = SA_RESTART;
 883         sigaction(SIGINT, &act, NULL);
 884         sigaction(SIGTERM, &act, NULL);
 885         sigaction(SIGALRM, &act, NULL);
 886         sigaction(SIGCHLD, &act, NULL);
 887
 888         if (init_uevent_netlink_sock() < 0) {
 889                 dbg("uevent socket not available");
 890         }
 891
 892         if (init_udevd_socket() < 0) {
 893                 if (errno == EADDRINUSE)
 894                         dbg("another udevd running, exit");
 895                 else
 896                         dbg("error initialising udevd socket: %s", strerror(errno));
 897
 898                 goto exit;
 899         }
 900
 901         /* override of forked udev binary, used for testing */
 902         udev_bin = getenv("UDEV_BIN");
 903         if (udev_bin != NULL)
 904                 info("udev binary is set to '%s'", udev_bin);
 905         else
 906                 udev_bin = UDEV_BIN;
 907
 908         /* init of expected_seqnum value */
 909         value = getenv("UDEVD_EXPECTED_SEQNUM");
 910         if (value) {
 911                 expected_seqnum = strtoull(value, NULL, 10);
 912                 info("initialize expected_seqnum to %llu", expected_seqnum);
 913         }
 914
 915         /* timeout to wait for missing events */
 916         value = getenv("UDEVD_EVENT_TIMEOUT");
 917         if (value)
 918                 event_timeout = strtoul(value, NULL, 10);
 919         else
 920                 event_timeout = UDEVD_EVENT_TIMEOUT;
 921         info("initialize event_timeout to %u", event_timeout);
 922
 923         /* maximum limit of forked childs */
 924         value = getenv("UDEVD_MAX_CHILDS");
 925         if (value)
 926                 max_childs = strtoul(value, NULL, 10);
 927         else
 928                 max_childs = UDEVD_MAX_CHILDS;
 929         info("initialize max_childs to %u", max_childs);
 930
 931         /* start to throttle forking if maximum number of _running_ childs is reached */
 932         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 933         if (value)
 934                 max_childs_running = strtoull(value, NULL, 10);
 935         else
 936                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 937         info("initialize max_childs_running to %u", max_childs_running);
 938
 939         FD_ZERO(&readfds);
 940         FD_SET(udevd_sock, &readfds);
 941         if (uevent_netlink_sock != -1)
 942                 FD_SET(uevent_netlink_sock, &readfds);
 943         FD_SET(pipefds[0], &readfds);
 944         maxsockplus = udevd_sock+1;
 945         while (1) {
 946                 struct uevent_msg *msg;
 947
 948                 fd_set workreadfds = readfds;
 949                 retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
 950
 951                 if (retval < 0) {
 952                         if (errno != EINTR)
 953                                 dbg("error in select: %s", strerror(errno));
 954                         continue;
 955                 }
 956
 957                 if (FD_ISSET(udevd_sock, &workreadfds)) {
 958                         msg = get_udevd_msg();
 959                         if (msg) {
 960                                 /* discard kernel messages if netlink is active */
 961                                 if (uevent_netlink_active && msg->type == UDEVD_UEVENT_UDEVSEND && msg->seqnum != 0) {
 962                                         dbg("skip uevent_helper message, netlink is active");
 963                                         free(msg);
 964                                         continue;
 965                                 }
 966                                 msg_queue_insert(msg);
 967                         }
 968                 }
 969
 970                 if (FD_ISSET(uevent_netlink_sock, &workreadfds)) {
 971                         msg = get_netlink_msg();
 972                         if (msg) {
 973                                 msg_queue_insert(msg);
 974                                 /* disable udevsend with first netlink message */
 975                                 if (!uevent_netlink_active) {
 976                                         info("uevent_nl message received, disable udevsend messages");
 977                                         uevent_netlink_active = 1;
 978                                 }
 979                         }
 980                 }
 981
 982                 if (FD_ISSET(pipefds[0], &workreadfds))
 983                         user_sighandler();
 984
 985                 if (sigchilds_waiting) {
 986                         sigchilds_waiting = 0;
 987                         reap_sigchilds();
 988                 }
 989
 990                 if (run_msg_q) {
 991                         run_msg_q = 0;
 992                         msg_queue_manager();
 993                 }
 994
 995                 if (run_exec_q) {
 996                          /* clean up running_list before calling exec_queue_manager() */
 997                         if (sigchilds_waiting) {
 998                                 sigchilds_waiting = 0;
 999                                 reap_sigchilds();
1000                         }
1001
1002                         run_exec_q = 0;
1003                         if (!stop_exec_q)
1004                                 exec_queue_manager();
1005                 }
1006         }
1007
1008 exit:
1009         logging_close();
1010         return 1;
1011 }