udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static struct udev_rules rules;
  49 static int udevd_sock = -1;
  50 static int uevent_netlink_sock = -1;
  51 static int inotify_fd = -1;
  52 static pid_t sid;
  53
  54 static int signal_pipe[2] = {-1, -1};
  55 static volatile int sigchilds_waiting;
  56 static volatile int udev_exit;
  57 static volatile int reload_config;
  58 static int run_exec_q;
  59 static int stop_exec_q;
  60 static int max_childs;
  61 static int max_childs_running;
  62 static char udev_log[32];
  63
  64 static LIST_HEAD(exec_list);
  65 static LIST_HEAD(running_list);
  66
  67
  68 #ifdef USE_LOG
  69 void log_message(int priority, const char *format, ...)
  70 {
  71         va_list args;
  72
  73         if (priority > udev_log_priority)
  74                 return;
  75
  76         va_start(args, format);
  77         vsyslog(priority, format, args);
  78         va_end(args);
  79 }
  80
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct udevd_uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* reset to default */
 104         act.sa_handler = SIG_DFL;
 105         sigaction(SIGINT, &act, NULL);
 106         sigaction(SIGTERM, &act, NULL);
 107         sigaction(SIGCHLD, &act, NULL);
 108         sigaction(SIGHUP, &act, NULL);
 109
 110         /* trigger timeout to prevent hanging processes */
 111         alarm(UDEV_ALARM_TIMEOUT);
 112
 113         /* reconstruct event environment from message */
 114         for (i = 0; msg->envp[i]; i++)
 115                 putenv(msg->envp[i]);
 116
 117         udev = udev_device_init();
 118         if (udev == NULL)
 119                 return -1;
 120         strlcpy(udev->action, msg->action, sizeof(udev->action));
 121         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 122         udev->devt = msg->devt;
 123
 124         retval = udev_device_event(&rules, udev);
 125
 126         /* run programs collected by RUN-key*/
 127         if (retval == 0 && !udev->ignore_device && udev_run) {
 128                 struct name_entry *name_loop;
 129
 130                 dbg("executing run list");
 131                 list_for_each_entry(name_loop, &udev->run_list, node) {
 132                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 133                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 134                         else {
 135                                 char program[PATH_SIZE];
 136
 137                                 strlcpy(program, name_loop->name, sizeof(program));
 138                                 udev_rules_apply_format(udev, program, sizeof(program));
 139                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 140                                                 (udev_log_priority >= LOG_INFO)))
 141                                         retval = -1;
 142                         }
 143                 }
 144         }
 145
 146         udev_device_cleanup(udev);
 147         return retval;
 148 }
 149
 150 enum event_state {
 151         EVENT_QUEUED,
 152         EVENT_FINISHED,
 153         EVENT_FAILED,
 154 };
 155
 156 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 157 {
 158         char filename[PATH_SIZE];
 159         char filename_failed[PATH_SIZE];
 160         size_t start, end, i;
 161         struct udevd_uevent_msg *loop_msg;
 162         int fd;
 163
 164         /* add location of queue files */
 165         strlcpy(filename, udev_root, sizeof(filename));
 166         strlcat(filename, "/", sizeof(filename));
 167         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 168         end = strlcat(filename, msg->devpath, sizeof(filename));
 169         if (end > sizeof(filename))
 170                 end = sizeof(filename);
 171
 172         /* replace '/' to transform path into a filename */
 173         for (i = start+1; i < end; i++)
 174                 if (filename[i] == '/')
 175                         filename[i] = PATH_TO_NAME_CHAR;
 176
 177         /* add location of failed files */
 178         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 179         strlcat(filename_failed, "/", sizeof(filename_failed));
 180         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 181         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 182         if (end > sizeof(filename_failed))
 183                 end = sizeof(filename_failed);
 184
 185         /* replace '/' to transform path into a filename */
 186         for (i = start+1; i < end; i++)
 187                 if (filename_failed[i] == '/')
 188                         filename_failed[i] = PATH_TO_NAME_CHAR;
 189
 190         switch (state) {
 191         case EVENT_QUEUED:
 192                 unlink(filename_failed);
 193                 delete_path(filename_failed);
 194                 create_path(filename);
 195                 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 196                 if (fd > 0)
 197                         close(fd);
 198                 return;
 199         case EVENT_FINISHED:
 200         case EVENT_FAILED:
 201                 unlink(filename_failed);
 202                 delete_path(filename_failed);
 203
 204                 /* don't remove, if events for the same path are still pending */
 205                 list_for_each_entry(loop_msg, &running_list, node)
 206                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 207                                 return;
 208
 209                 list_for_each_entry(loop_msg, &exec_list, node)
 210                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 211                                 return;
 212
 213                 /* move failed events to the failed directory */
 214                 if (state == EVENT_FAILED) {
 215                         create_path(filename_failed);
 216                         rename(filename, filename_failed);
 217                 } else {
 218                         unlink(filename);
 219                 }
 220
 221                 /* clean up the queue directory */
 222                 delete_path(filename);
 223
 224                 return;
 225         }
 226 }
 227
 228 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 229 {
 230         list_del(&msg->node);
 231
 232         /* mark as failed, if add event returns non-zero */
 233         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 234                 export_event_state(msg, EVENT_FAILED);
 235         else
 236                 export_event_state(msg, EVENT_FINISHED);
 237
 238         free(msg);
 239 }
 240
 241 static void udev_event_run(struct udevd_uevent_msg *msg)
 242 {
 243         pid_t pid;
 244         int retval;
 245
 246         pid = fork();
 247         switch (pid) {
 248         case 0:
 249                 /* child */
 250                 close(uevent_netlink_sock);
 251                 close(udevd_sock);
 252                 if (inotify_fd >= 0)
 253                         close(inotify_fd);
 254                 close(signal_pipe[READ_END]);
 255                 close(signal_pipe[WRITE_END]);
 256                 logging_close();
 257
 258                 logging_init("udevd-event");
 259                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 260
 261                 retval = udev_event_process(msg);
 262                 info("seq %llu finished", msg->seqnum);
 263
 264                 logging_close();
 265                 if (retval)
 266                         exit(1);
 267                 exit(0);
 268         case -1:
 269                 err("fork of child failed: %s", strerror(errno));
 270                 msg_queue_delete(msg);
 271                 break;
 272         default:
 273                 /* get SIGCHLD in main loop */
 274                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 275                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 276                 msg->pid = pid;
 277         }
 278 }
 279
 280 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 281 {
 282         char filename[PATH_SIZE];
 283         int fd;
 284
 285         msg->queue_time = time(NULL);
 286
 287         strlcpy(filename, udev_root, sizeof(filename));
 288         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 289         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 290         if (fd >= 0) {
 291                 char str[32];
 292                 int len;
 293
 294                 len = sprintf(str, "%llu\n", msg->seqnum);
 295                 write(fd, str, len);
 296                 close(fd);
 297         }
 298
 299         export_event_state(msg, EVENT_QUEUED);
 300
 301         /* run all events with a timeout set immediately */
 302         if (msg->timeout != 0) {
 303                 list_add_tail(&msg->node, &running_list);
 304                 udev_event_run(msg);
 305                 return;
 306         }
 307
 308         list_add_tail(&msg->node, &exec_list);
 309         run_exec_q = 1;
 310 }
 311
 312 static int mem_size_mb(void)
 313 {
 314         int f;
 315         char buf[8192];
 316         long int len;
 317         const char *pos;
 318         long int memsize;
 319
 320         f = open("/proc/meminfo", O_RDONLY);
 321         if (f == -1)
 322                 return -1;
 323
 324         len = read(f, buf, sizeof(buf)-1);
 325         close(f);
 326
 327         if (len <= 0)
 328                 return -1;
 329         buf[len] = '\0';
 330
 331         pos = strstr(buf, "MemTotal: ");
 332         if (pos == NULL)
 333                 return -1;
 334
 335         if (sscanf(pos, "MemTotal: %ld kB", &memsize) != 1)
 336                 return -1;
 337
 338         return memsize / 1024;
 339 }
 340
 341 static int cpu_count(void)
 342 {
 343         int f;
 344         char buf[32768];
 345         int len;
 346         const char *pos;
 347         int count = 0;
 348
 349         f = open("/proc/stat", O_RDONLY);
 350         if (f == -1)
 351                 return -1;
 352
 353         len = read(f, buf, sizeof(buf)-1);
 354         close(f);
 355         if (len <= 0)
 356                 return -1;
 357         buf[len] = '\0';
 358
 359         pos = strstr(buf, "cpu");
 360         if (pos == NULL)
 361                 return -1;
 362
 363         while (pos != NULL) {
 364                 if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
 365                         count++;
 366                 pos = strstr(&pos[3], "cpu");
 367         }
 368
 369         if (count == 0)
 370                 return -1;
 371         return count;
 372 }
 373
 374 static int running_processes(void)
 375 {
 376         int f;
 377         char buf[32768];
 378         int len;
 379         int running;
 380         const char *pos;
 381
 382         f = open("/proc/stat", O_RDONLY);
 383         if (f == -1)
 384                 return -1;
 385
 386         len = read(f, buf, sizeof(buf)-1);
 387         close(f);
 388         if (len <= 0)
 389                 return -1;
 390         buf[len] = '\0';
 391
 392         pos = strstr(buf, "procs_running ");
 393         if (pos == NULL)
 394                 return -1;
 395
 396         if (sscanf(pos, "procs_running %u", &running) != 1)
 397                 return -1;
 398
 399         return running;
 400 }
 401
 402 /* return the number of process es in our session, count only until limit */
 403 static int running_processes_in_session(pid_t session, int limit)
 404 {
 405         DIR *dir;
 406         struct dirent *dent;
 407         int running = 0;
 408
 409         dir = opendir("/proc");
 410         if (!dir)
 411                 return -1;
 412
 413         /* read process info from /proc */
 414         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 415                 int f;
 416                 char procdir[64];
 417                 char line[256];
 418                 const char *pos;
 419                 char state;
 420                 pid_t ppid, pgrp, sess;
 421                 int len;
 422
 423                 if (!isdigit(dent->d_name[0]))
 424                         continue;
 425
 426                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 427                 procdir[sizeof(procdir)-1] = '\0';
 428
 429                 f = open(procdir, O_RDONLY);
 430                 if (f == -1)
 431                         continue;
 432
 433                 len = read(f, line, sizeof(line)-1);
 434                 close(f);
 435
 436                 if (len <= 0)
 437                         continue;
 438                 else
 439                         line[len] = '\0';
 440
 441                 /* skip ugly program name */
 442                 pos = strrchr(line, ')') + 2;
 443                 if (pos == NULL)
 444                         continue;
 445
 446                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 447                         continue;
 448
 449                 /* count only processes in our session */
 450                 if (sess != session)
 451                         continue;
 452
 453                 /* count only running, no sleeping processes */
 454                 if (state != 'R')
 455                         continue;
 456
 457                 running++;
 458                 if (limit > 0 && running >= limit)
 459                         break;
 460         }
 461         closedir(dir);
 462
 463         return running;
 464 }
 465
 466 static int compare_devpath(const char *running, const char *waiting)
 467 {
 468         int i;
 469
 470         for (i = 0; i < PATH_SIZE; i++) {
 471                 /* identical device event found */
 472                 if (running[i] == '\0' && waiting[i] == '\0')
 473                         return 1;
 474
 475                 /* parent device event found */
 476                 if (running[i] == '\0' && waiting[i] == '/')
 477                         return 2;
 478
 479                 /* child device event found */
 480                 if (running[i] == '/' && waiting[i] == '\0')
 481                         return 3;
 482
 483                 /* no matching event */
 484                 if (running[i] != waiting[i])
 485                         break;
 486         }
 487
 488         return 0;
 489 }
 490
 491 /* returns still running task for the same device, its parent or its physical device */
 492 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 493 {
 494         struct udevd_uevent_msg *loop_msg;
 495         int childs_count = 0;
 496
 497         list_for_each_entry(loop_msg, &running_list, node) {
 498                 if (limit && childs_count++ > limit) {
 499                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 500                         return 1;
 501                 }
 502
 503                 /* return running parent/child device event */
 504                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 505                         dbg("%llu, child device event still running %llu (%s)",
 506                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 507                         return 2;
 508                 }
 509
 510                 /* return running physical device event */
 511                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 512                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 513                                 dbg("%llu, physical device event still running %llu (%s)",
 514                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 515                                 return 3;
 516                         }
 517         }
 518
 519         return 0;
 520 }
 521
 522 /* exec queue management routine executes the events and serializes events in the same sequence */
 523 static void msg_queue_manager(void)
 524 {
 525         struct udevd_uevent_msg *loop_msg;
 526         struct udevd_uevent_msg *tmp_msg;
 527         int running;
 528
 529         if (list_empty(&exec_list))
 530                 return;
 531
 532         running = running_processes();
 533         dbg("%d processes runnning on system", running);
 534         if (running < 0)
 535                 running = max_childs_running;
 536
 537         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 538                 /* check running processes in our session and possibly throttle */
 539                 if (running >= max_childs_running) {
 540                         running = running_processes_in_session(sid, max_childs_running+10);
 541                         dbg("at least %d processes running in session", running);
 542                         if (running >= max_childs_running) {
 543                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 544                                 return;
 545                         }
 546                 }
 547
 548                 /* don't run two processes for the same devpath and wait for the parent*/
 549                 if (running_with_devpath(loop_msg, max_childs)) {
 550                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 551                         continue;
 552                 }
 553
 554                 /* move event to run list */
 555                 list_move_tail(&loop_msg->node, &running_list);
 556                 udev_event_run(loop_msg);
 557                 running++;
 558                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 559         }
 560 }
 561
 562 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 563 {
 564         int bufpos;
 565         int i;
 566         struct udevd_uevent_msg *msg;
 567         char *physdevdriver_key = NULL;
 568         int maj = 0;
 569         int min = 0;
 570
 571         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 572         if (msg == NULL)
 573                 return NULL;
 574         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 575
 576         /* copy environment buffer and reconstruct envp */
 577         memcpy(msg->envbuf, buf, buf_size);
 578         bufpos = 0;
 579         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 580                 int keylen;
 581                 char *key;
 582
 583                 key = &msg->envbuf[bufpos];
 584                 keylen = strlen(key);
 585                 msg->envp[i] = key;
 586                 bufpos += keylen + 1;
 587                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 588
 589                 /* remember some keys for further processing */
 590                 if (strncmp(key, "ACTION=", 7) == 0)
 591                         msg->action = &key[7];
 592                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 593                         msg->devpath = &key[8];
 594                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 595                         msg->subsystem = &key[10];
 596                 else if (strncmp(key, "DRIVER=", 7) == 0)
 597                         msg->driver = &key[7];
 598                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 599                         msg->seqnum = strtoull(&key[7], NULL, 10);
 600                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 601                         msg->physdevpath = &key[12];
 602                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 603                         physdevdriver_key = key;
 604                 else if (strncmp(key, "MAJOR=", 6) == 0)
 605                         maj = strtoull(&key[6], NULL, 10);
 606                 else if (strncmp(key, "MINOR=", 6) == 0)
 607                         min = strtoull(&key[6], NULL, 10);
 608                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 609                         msg->timeout = strtoull(&key[8], NULL, 10);
 610         }
 611         msg->devt = makedev(maj, min);
 612         msg->envp[i++] = "UDEVD_EVENT=1";
 613
 614         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 615                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 616                 msg->envp[i++] = &physdevdriver_key[7];
 617                 msg->driver = &physdevdriver_key[14];
 618         }
 619
 620         msg->envp[i] = NULL;
 621
 622         if (msg->devpath == NULL || msg->action == NULL) {
 623                 info("DEVPATH or ACTION missing, ignore message");
 624                 free(msg);
 625                 return NULL;
 626         }
 627         return msg;
 628 }
 629
 630 /* receive the udevd message from userspace */
 631 static void get_ctrl_msg(void)
 632 {
 633         struct udevd_ctrl_msg ctrl_msg;
 634         ssize_t size;
 635         struct msghdr smsg;
 636         struct cmsghdr *cmsg;
 637         struct iovec iov;
 638         struct ucred *cred;
 639         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 640         int *intval;
 641
 642         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 643         iov.iov_base = &ctrl_msg;
 644         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 645
 646         memset(&smsg, 0x00, sizeof(struct msghdr));
 647         smsg.msg_iov = &iov;
 648         smsg.msg_iovlen = 1;
 649         smsg.msg_control = cred_msg;
 650         smsg.msg_controllen = sizeof(cred_msg);
 651
 652         size = recvmsg(udevd_sock, &smsg, 0);
 653         if (size <  0) {
 654                 if (errno != EINTR)
 655                         err("unable to receive user udevd message: %s", strerror(errno));
 656                 return;
 657         }
 658         cmsg = CMSG_FIRSTHDR(&smsg);
 659         cred = (struct ucred *) CMSG_DATA(cmsg);
 660
 661         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 662                 err("no sender credentials received, message ignored");
 663                 return;
 664         }
 665
 666         if (cred->uid != 0) {
 667                 err("sender uid=%i, message ignored", cred->uid);
 668                 return;
 669         }
 670
 671         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 672                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 673                 return;
 674         }
 675
 676         switch (ctrl_msg.type) {
 677         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 678                 info("udevd message (STOP_EXEC_QUEUE) received");
 679                 stop_exec_q = 1;
 680                 break;
 681         case UDEVD_CTRL_START_EXEC_QUEUE:
 682                 info("udevd message (START_EXEC_QUEUE) received");
 683                 stop_exec_q = 0;
 684                 msg_queue_manager();
 685                 break;
 686         case UDEVD_CTRL_SET_LOG_LEVEL:
 687                 intval = (int *) ctrl_msg.buf;
 688                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 689                 udev_log_priority = *intval;
 690                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 691                 putenv(udev_log);
 692                 break;
 693         case UDEVD_CTRL_SET_MAX_CHILDS:
 694                 intval = (int *) ctrl_msg.buf;
 695                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 696                 max_childs = *intval;
 697                 break;
 698         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 699                 intval = (int *) ctrl_msg.buf;
 700                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 701                 max_childs_running = *intval;
 702                 break;
 703         case UDEVD_CTRL_RELOAD_RULES:
 704                 info("udevd message (RELOAD_RULES) received");
 705                 reload_config = 1;
 706                 break;
 707         default:
 708                 err("unknown control message type");
 709         }
 710 }
 711
 712 /* receive the kernel user event message and do some sanity checks */
 713 static struct udevd_uevent_msg *get_netlink_msg(void)
 714 {
 715         struct udevd_uevent_msg *msg;
 716         int bufpos;
 717         ssize_t size;
 718         static char buffer[UEVENT_BUFFER_SIZE+512];
 719         char *pos;
 720
 721         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 722         if (size <  0) {
 723                 if (errno != EINTR)
 724                         err("unable to receive kernel netlink message: %s", strerror(errno));
 725                 return NULL;
 726         }
 727
 728         if ((size_t)size > sizeof(buffer)-1)
 729                 size = sizeof(buffer)-1;
 730         buffer[size] = '\0';
 731         dbg("uevent_size=%zi", size);
 732
 733         /* start of event payload */
 734         bufpos = strlen(buffer)+1;
 735         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 736         if (msg == NULL)
 737                 return NULL;
 738
 739         /* validate message */
 740         pos = strchr(buffer, '@');
 741         if (pos == NULL) {
 742                 err("invalid uevent '%s'", buffer);
 743                 free(msg);
 744                 return NULL;
 745         }
 746         pos[0] = '\0';
 747
 748         if (msg->action == NULL) {
 749                 info("no ACTION in payload found, skip event '%s'", buffer);
 750                 free(msg);
 751                 return NULL;
 752         }
 753
 754         if (strcmp(msg->action, buffer) != 0) {
 755                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 756                 free(msg);
 757                 return NULL;
 758         }
 759
 760         return msg;
 761 }
 762
 763 static void asmlinkage sig_handler(int signum)
 764 {
 765         switch (signum) {
 766                 case SIGINT:
 767                 case SIGTERM:
 768                         udev_exit = 1;
 769                         break;
 770                 case SIGCHLD:
 771                         /* set flag, then write to pipe if needed */
 772                         sigchilds_waiting = 1;
 773                         break;
 774                 case SIGHUP:
 775                         reload_config = 1;
 776                         break;
 777         }
 778
 779         /* write to pipe, which will wakeup select() in our mainloop */
 780         write(signal_pipe[WRITE_END], "", 1);
 781 }
 782
 783 static void udev_done(int pid, int exitstatus)
 784 {
 785         /* find msg associated with pid and delete it */
 786         struct udevd_uevent_msg *msg;
 787
 788         list_for_each_entry(msg, &running_list, node) {
 789                 if (msg->pid == pid) {
 790                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 791                              exitstatus, time(NULL) - msg->queue_time);
 792                         msg->exitstatus = exitstatus;
 793                         msg_queue_delete(msg);
 794
 795                         /* there may be events waiting with the same devpath */
 796                         run_exec_q = 1;
 797                         return;
 798                 }
 799         }
 800 }
 801
 802 static void reap_sigchilds(void)
 803 {
 804         pid_t pid;
 805         int status;
 806
 807         while (1) {
 808                 pid = waitpid(-1, &status, WNOHANG);
 809                 if (pid <= 0)
 810                         break;
 811                 if (WIFEXITED(status))
 812                         status = WEXITSTATUS(status);
 813                 else if (WIFSIGNALED(status))
 814                         status = WTERMSIG(status) + 128;
 815                 else
 816                         status = 0;
 817                 udev_done(pid, status);
 818         }
 819 }
 820
 821 static int init_udevd_socket(void)
 822 {
 823         struct sockaddr_un saddr;
 824         socklen_t addrlen;
 825         const int feature_on = 1;
 826         int retval;
 827
 828         memset(&saddr, 0x00, sizeof(saddr));
 829         saddr.sun_family = AF_LOCAL;
 830         /* use abstract namespace for socket path */
 831         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 832         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 833
 834         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 835         if (udevd_sock == -1) {
 836                 err("error getting socket: %s", strerror(errno));
 837                 return -1;
 838         }
 839
 840         /* the bind takes care of ensuring only one copy running */
 841         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 842         if (retval < 0) {
 843                 err("bind failed: %s", strerror(errno));
 844                 close(udevd_sock);
 845                 udevd_sock = -1;
 846                 return -1;
 847         }
 848
 849         /* enable receiving of the sender credentials */
 850         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 851
 852         return 0;
 853 }
 854
 855 static int init_uevent_netlink_sock(void)
 856 {
 857         struct sockaddr_nl snl;
 858         const int buffersize = 16 * 1024 * 1024;
 859         int retval;
 860
 861         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 862         snl.nl_family = AF_NETLINK;
 863         snl.nl_pid = getpid();
 864         snl.nl_groups = 1;
 865
 866         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 867         if (uevent_netlink_sock == -1) {
 868                 err("error getting socket: %s", strerror(errno));
 869                 return -1;
 870         }
 871
 872         /* set receive buffersize */
 873         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 874
 875         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 876         if (retval < 0) {
 877                 err("bind failed: %s", strerror(errno));
 878                 close(uevent_netlink_sock);
 879                 uevent_netlink_sock = -1;
 880                 return -1;
 881         }
 882         return 0;
 883 }
 884
 885 static void export_initial_seqnum(void)
 886 {
 887         char filename[PATH_SIZE];
 888         int fd;
 889         char seqnum[32];
 890         ssize_t len = 0;
 891
 892         strlcpy(filename, sysfs_path, sizeof(filename));
 893         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 894         fd = open(filename, O_RDONLY);
 895         if (fd >= 0) {
 896                 len = read(fd, seqnum, sizeof(seqnum)-1);
 897                 close(fd);
 898         }
 899         if (len <= 0) {
 900                 strcpy(seqnum, "0\n");
 901                 len = 3;
 902         }
 903         strlcpy(filename, udev_root, sizeof(filename));
 904         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 905         create_path(filename);
 906         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 907         if (fd >= 0) {
 908                 write(fd, seqnum, len);
 909                 close(fd);
 910         }
 911 }
 912
 913 int main(int argc, char *argv[], char *envp[])
 914 {
 915         int retval;
 916         int fd;
 917         struct sigaction act;
 918         fd_set readfds;
 919         const char *value;
 920         int daemonize = 0;
 921         int option;
 922         static const struct option options[] = {
 923                 { "daemon", 0, NULL, 'd' },
 924                 { "help", 0, NULL, 'h' },
 925                 {}
 926         };
 927         int rc = 1;
 928         int maxfd;
 929
 930         logging_init("udevd");
 931         udev_config_init();
 932         selinux_init();
 933         dbg("version %s", UDEV_VERSION);
 934
 935         /* parse commandline options */
 936         while (1) {
 937                 option = getopt_long(argc, argv, "dtvh", options, NULL);
 938                 if (option == -1)
 939                         break;
 940
 941                 switch (option) {
 942                 case 'd':
 943                         daemonize = 1;
 944                         break;
 945                 case 'h':
 946                         printf("Usage: udevd [--help] [--daemon]\n");
 947                         goto exit;
 948                 default:
 949                         goto exit;
 950                 }
 951         }
 952
 953         if (getuid() != 0) {
 954                 fprintf(stderr, "root privileges required\n");
 955                 err("root privileges required");
 956                 goto exit;
 957         }
 958
 959         /* init sockets to receive events */
 960         if (init_udevd_socket() < 0) {
 961                 if (errno == EADDRINUSE) {
 962                         fprintf(stderr, "another udev daemon already running\n");
 963                         err("another udev daemon already running");
 964                         rc = 1;
 965                 } else {
 966                         fprintf(stderr, "error initializing udevd socket\n");
 967                         err("error initializing udevd socket");
 968                         rc = 2;
 969                 }
 970                 goto exit;
 971         }
 972
 973         if (init_uevent_netlink_sock() < 0) {
 974                 fprintf(stderr, "error initializing netlink socket\n");
 975                 err("error initializing netlink socket");
 976                 rc = 3;
 977                 goto exit;
 978         }
 979
 980         /* parse the rules and keep them in memory */
 981         sysfs_init();
 982         udev_rules_init(&rules, 1);
 983
 984         export_initial_seqnum();
 985
 986         if (daemonize) {
 987                 pid_t pid;
 988
 989                 pid = fork();
 990                 switch (pid) {
 991                 case 0:
 992                         dbg("daemonized fork running");
 993                         break;
 994                 case -1:
 995                         err("fork of daemon failed: %s", strerror(errno));
 996                         rc = 4;
 997                         goto exit;
 998                 default:
 999                         dbg("child [%u] running, parent exits", pid);
1000                         rc = 0;
1001                         goto exit;
1002                 }
1003         }
1004
1005         /* redirect std fd's */
1006         fd = open("/dev/null", O_RDWR);
1007         if (fd >= 0) {
1008                 dup2(fd, STDIN_FILENO);
1009                 dup2(fd, STDOUT_FILENO);
1010                 dup2(fd, STDERR_FILENO);
1011                 if (fd > STDERR_FILENO)
1012                         close(fd);
1013         } else
1014                 err("error opening /dev/null: %s", strerror(errno));
1015
1016         /* set scheduling priority for the daemon */
1017         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1018
1019         chdir("/");
1020         umask(022);
1021
1022         /* become session leader */
1023         sid = setsid();
1024         dbg("our session is %d", sid);
1025
1026         /* OOM_DISABLE == -17 */
1027         fd = open("/proc/self/oom_adj", O_RDWR);
1028         if (fd < 0)
1029                 err("error disabling OOM: %s", strerror(errno));
1030         else {
1031                 write(fd, "-17", 3);
1032                 close(fd);
1033         }
1034
1035         /* setup signal handler pipe */
1036         retval = pipe(signal_pipe);
1037         if (retval < 0) {
1038                 err("error getting pipes: %s", strerror(errno));
1039                 goto exit;
1040         }
1041
1042         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1043         if (retval < 0) {
1044                 err("error fcntl on read pipe: %s", strerror(errno));
1045                 goto exit;
1046         }
1047         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1048         if (retval < 0) {
1049                 err("error fcntl on read pipe: %s", strerror(errno));
1050                 goto exit;
1051         }
1052
1053         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1054         if (retval < 0) {
1055                 err("error fcntl on write pipe: %s", strerror(errno));
1056                 goto exit;
1057         }
1058         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1059         if (retval < 0) {
1060                 err("error fcntl on write pipe: %s", strerror(errno));
1061                 goto exit;
1062         }
1063
1064         /* set signal handlers */
1065         memset(&act, 0x00, sizeof(struct sigaction));
1066         act.sa_handler = (void (*)(int)) sig_handler;
1067         sigemptyset(&act.sa_mask);
1068         act.sa_flags = SA_RESTART;
1069         sigaction(SIGINT, &act, NULL);
1070         sigaction(SIGTERM, &act, NULL);
1071         sigaction(SIGCHLD, &act, NULL);
1072         sigaction(SIGHUP, &act, NULL);
1073
1074         /* watch rules directory */
1075         inotify_fd = inotify_init();
1076         if (inotify_fd >= 0)
1077                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1078         else if (errno == ENOSYS)
1079                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
1080         else
1081                 err("inotify_init failed: %s", strerror(errno));
1082
1083         /* maximum limit of forked childs */
1084         value = getenv("UDEVD_MAX_CHILDS");
1085         if (value)
1086                 max_childs = strtoul(value, NULL, 10);
1087         else {
1088                 int memsize = mem_size_mb();
1089                 if (memsize > 0)
1090                         max_childs = 128 + (memsize / 4);
1091                 else
1092                         max_childs = UDEVD_MAX_CHILDS;
1093         }
1094         info("initialize max_childs to %u", max_childs);
1095
1096         /* start to throttle forking if maximum number of _running_ childs is reached */
1097         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1098         if (value)
1099                 max_childs_running = strtoull(value, NULL, 10);
1100         else {
1101                 int cpus = cpu_count();
1102                 if (cpus > 0)
1103                         max_childs_running = 8 + (8 * cpus);
1104                 else
1105                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1106         }
1107         info("initialize max_childs_running to %u", max_childs_running);
1108
1109         /* clear environment for forked event processes */
1110         clearenv();
1111
1112         /* export log_priority , as called programs may want to follow that setting */
1113         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1114         putenv(udev_log);
1115
1116         maxfd = udevd_sock;
1117         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1118         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1119         maxfd = UDEV_MAX(maxfd, inotify_fd);
1120
1121         while (!udev_exit) {
1122                 struct udevd_uevent_msg *msg;
1123                 int fdcount;
1124
1125                 FD_ZERO(&readfds);
1126                 FD_SET(signal_pipe[READ_END], &readfds);
1127                 FD_SET(udevd_sock, &readfds);
1128                 FD_SET(uevent_netlink_sock, &readfds);
1129                 if (inotify_fd >= 0)
1130                         FD_SET(inotify_fd, &readfds);
1131
1132                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1133                 if (fdcount < 0) {
1134                         if (errno != EINTR)
1135                                 err("error in select: %s", strerror(errno));
1136                         continue;
1137                 }
1138
1139                 /* get control message */
1140                 if (FD_ISSET(udevd_sock, &readfds))
1141                         get_ctrl_msg();
1142
1143                 /* get netlink message */
1144                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1145                         msg = get_netlink_msg();
1146                         if (msg)
1147                                 msg_queue_insert(msg);
1148                 }
1149
1150                 /* received a signal, clear our notification pipe */
1151                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1152                         char buf[256];
1153
1154                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1155                 }
1156
1157                 /* rules directory inotify watch */
1158                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1159                         int nbytes;
1160
1161                         /* discard all possible events, we can just reload the config */
1162                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1163                                 char *buf;
1164
1165                                 reload_config = 1;
1166                                 buf = malloc(nbytes);
1167                                 if (!buf) {
1168                                         err("error getting buffer for inotify, disable watching");
1169                                         close(inotify_fd);
1170                                         inotify_fd = -1;
1171                                 }
1172                                 read(inotify_fd, buf, nbytes);
1173                                 free(buf);
1174                         }
1175                 }
1176
1177                 /* rules changed, set by inotify or a HUP signal */
1178                 if (reload_config) {
1179                         reload_config = 0;
1180                         udev_rules_cleanup(&rules);
1181                         udev_rules_init(&rules, 1);
1182                 }
1183
1184                 /* forked child has returned */
1185                 if (sigchilds_waiting) {
1186                         sigchilds_waiting = 0;
1187                         reap_sigchilds();
1188                 }
1189
1190                 if (run_exec_q) {
1191                         run_exec_q = 0;
1192                         if (!stop_exec_q)
1193                                 msg_queue_manager();
1194                 }
1195         }
1196         rc = 0;
1197
1198 exit:
1199         udev_rules_cleanup(&rules);
1200         sysfs_cleanup();
1201
1202         if (signal_pipe[READ_END] >= 0)
1203                 close(signal_pipe[READ_END]);
1204         if (signal_pipe[WRITE_END] >= 0)
1205                 close(signal_pipe[WRITE_END]);
1206
1207         if (udevd_sock >= 0)
1208                 close(udevd_sock);
1209         if (inotify_fd >= 0)
1210                 close(inotify_fd);
1211         if (uevent_netlink_sock >= 0)
1212                 close(uevent_netlink_sock);
1213
1214         logging_close();
1215
1216         return rc;
1217 }