src/udev/udevadm-settle.c

   1 /*
   2  * Copyright (C) 2006-2009 Kay Sievers <kay@vrfy.org>
   3  * Copyright (C) 2009 Canonical Ltd.
   4  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <dirent.h>
  27 #include <fcntl.h>
  28 #include <syslog.h>
  29 #include <getopt.h>
  30 #include <signal.h>
  31 #include <time.h>
  32 #include <sys/inotify.h>
  33 #include <sys/poll.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36
  37 #include "udev.h"
  38 #include "udev-util.h"
  39 #include "util.h"
  40
  41 static void help(void) {
  42         printf("Usage: udevadm settle OPTIONS\n"
  43                "  -t,--timeout=<seconds>     maximum time to wait for events\n"
  44                "  -E,--exit-if-exists=<file> stop waiting if file exists\n"
  45                "  -h,--help\n\n");
  46 }
  47
  48 static int adm_settle(struct udev *udev, int argc, char *argv[])
  49 {
  50         static const struct option options[] = {
  51                 { "seq-start",      required_argument, NULL, '\0' }, /* removed */
  52                 { "seq-end",        required_argument, NULL, '\0' }, /* removed */
  53                 { "timeout",        required_argument, NULL, 't' },
  54                 { "exit-if-exists", required_argument, NULL, 'E' },
  55                 { "quiet",          no_argument,       NULL, 'q' },  /* removed */
  56                 { "help",           no_argument,       NULL, 'h' },
  57                 {}
  58         };
  59         const char *exists = NULL;
  60         unsigned int timeout = 120;
  61         struct pollfd pfd[1] = { {.fd = -1}, };
  62         int rc = EXIT_FAILURE, c;
  63
  64         while ((c = getopt_long(argc, argv, "s:e:t:E:qh", options, NULL)) >= 0) {
  65                 switch (c) {
  66                 case 't': {
  67                         int r;
  68
  69                         r = safe_atou(optarg, &timeout);
  70                         if (r < 0) {
  71                                 fprintf(stderr, "Invalid timeout value '%s': %s\n",
  72                                         optarg, strerror(-r));
  73                                 exit(EXIT_FAILURE);
  74                         };
  75                         break;
  76                 }
  77                 case 'E':
  78                         exists = optarg;
  79                         break;
  80                 case 'h':
  81                         help();
  82                         exit(EXIT_SUCCESS);
  83                 case '?':
  84                         exit(EXIT_FAILURE);
  85                 default:
  86                         assert_not_reached("Unknown argument");
  87                 }
  88         }
  89
  90         if (optind < argc) {
  91                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
  92                 exit(EXIT_FAILURE);
  93         }
  94
  95         /* guarantee that the udev daemon isn't pre-processing */
  96         if (getuid() == 0) {
  97                 struct udev_ctrl *uctrl;
  98
  99                 uctrl = udev_ctrl_new(udev);
 100                 if (uctrl != NULL) {
 101                         if (udev_ctrl_send_ping(uctrl, timeout) < 0) {
 102                                 log_debug("no connection to daemon");
 103                                 udev_ctrl_unref(uctrl);
 104                                 rc = EXIT_SUCCESS;
 105                                 goto out;
 106                         }
 107                         udev_ctrl_unref(uctrl);
 108                 }
 109         }
 110
 111         pfd[0].events = POLLIN;
 112         pfd[0].fd = inotify_init1(IN_CLOEXEC);
 113         if (pfd[0].fd < 0) {
 114                 log_error("inotify_init failed: %m");
 115                 goto out;
 116         }
 117
 118         if (inotify_add_watch(pfd[0].fd, "/run/udev/queue" , IN_DELETE) < 0) {
 119                 log_debug("watching /run/udev failed");
 120                 goto out;
 121         }
 122
 123         for (;;) {
 124                 if (exists && access(exists, F_OK) >= 0) {
 125                         rc = EXIT_SUCCESS;
 126                         break;
 127                 }
 128
 129                 /* exit if queue is empty */
 130                 if (access("/run/udev/queue", F_OK) < 0) {
 131                         rc = EXIT_SUCCESS;
 132                         break;
 133                 }
 134
 135                 /* wake up when "queue" file is deleted */
 136                 if (poll(pfd, 1, 100) > 0 && pfd[0].revents & POLLIN) {
 137                         char buf[sizeof(struct inotify_event) + PATH_MAX];
 138
 139                         read(pfd[0].fd, buf, sizeof(buf));
 140                 }
 141         }
 142
 143 out:
 144         if (pfd[0].fd >= 0)
 145                 close(pfd[0].fd);
 146         return rc;
 147 }
 148
 149 const struct udevadm_cmd udevadm_settle = {
 150         .name = "settle",
 151         .cmd = adm_settle,
 152         .help = "wait for pending udev events",
 153 };