src/udev/udevadm-settle.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /*
   4  * Copyright (C) 2006-2009 Kay Sievers <kay@vrfy.org>
   5  * Copyright (C) 2009 Canonical Ltd.
   6  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   7  *
   8  * This program is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation, either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <errno.h>
  23 #include <getopt.h>
  24 #include <poll.h>
  25 #include <stddef.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include "parse-util.h"
  32 #include "udev.h"
  33 #include "util.h"
  34
  35 static void help(void) {
  36         printf("%s settle OPTIONS\n\n"
  37                "Wait for pending udev events.\n\n"
  38                "  -h --help                 Show this help\n"
  39                "     --version              Show package version\n"
  40                "  -t --timeout=SECONDS      Maximum time to wait for events\n"
  41                "  -E --exit-if-exists=FILE  Stop waiting if file exists\n"
  42                , program_invocation_short_name);
  43 }
  44
  45 static int adm_settle(struct udev *udev, int argc, char *argv[]) {
  46         static const struct option options[] = {
  47                 { "timeout",        required_argument, NULL, 't' },
  48                 { "exit-if-exists", required_argument, NULL, 'E' },
  49                 { "help",           no_argument,       NULL, 'h' },
  50                 { "seq-start",      required_argument, NULL, 's' }, /* removed */
  51                 { "seq-end",        required_argument, NULL, 'e' }, /* removed */
  52                 { "quiet",          no_argument,       NULL, 'q' }, /* removed */
  53                 {}
  54         };
  55         usec_t deadline;
  56         const char *exists = NULL;
  57         unsigned int timeout = 120;
  58         struct pollfd pfd[1] = { {.fd = -1}, };
  59         int c;
  60         struct udev_queue *queue;
  61         int rc = EXIT_FAILURE;
  62
  63         while ((c = getopt_long(argc, argv, "t:E:hs:e:q", options, NULL)) >= 0) {
  64                 switch (c) {
  65
  66                 case 't': {
  67                         int r;
  68
  69                         r = safe_atou(optarg, &timeout);
  70                         if (r < 0) {
  71                                 log_error_errno(r, "Invalid timeout value '%s': %m", optarg);
  72                                 return EXIT_FAILURE;
  73                         }
  74                         break;
  75                 }
  76
  77                 case 'E':
  78                         exists = optarg;
  79                         break;
  80
  81                 case 'h':
  82                         help();
  83                         return EXIT_SUCCESS;
  84
  85                 case 's':
  86                 case 'e':
  87                 case 'q':
  88                         log_info("Option -%c no longer supported.", c);
  89                         return EXIT_FAILURE;
  90
  91                 case '?':
  92                         return EXIT_FAILURE;
  93
  94                 default:
  95                         assert_not_reached("Unknown argument");
  96                 }
  97         }
  98
  99         if (optind < argc) {
 100                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
 101                 return EXIT_FAILURE;
 102         }
 103
 104         deadline = now(CLOCK_MONOTONIC) + timeout * USEC_PER_SEC;
 105
 106         /* guarantee that the udev daemon isn't pre-processing */
 107         if (getuid() == 0) {
 108                 struct udev_ctrl *uctrl;
 109
 110                 uctrl = udev_ctrl_new(udev);
 111                 if (uctrl != NULL) {
 112                         if (udev_ctrl_send_ping(uctrl, MAX(5U, timeout)) < 0) {
 113                                 log_debug("no connection to daemon");
 114                                 udev_ctrl_unref(uctrl);
 115                                 return EXIT_SUCCESS;
 116                         }
 117                         udev_ctrl_unref(uctrl);
 118                 }
 119         }
 120
 121         queue = udev_queue_new(udev);
 122         if (!queue) {
 123                 log_error("unable to get udev queue");
 124                 return EXIT_FAILURE;
 125         }
 126
 127         pfd[0].events = POLLIN;
 128         pfd[0].fd = udev_queue_get_fd(queue);
 129         if (pfd[0].fd < 0) {
 130                 log_debug("queue is empty, nothing to watch");
 131                 rc = EXIT_SUCCESS;
 132                 goto out;
 133         }
 134
 135         for (;;) {
 136                 if (exists && access(exists, F_OK) >= 0) {
 137                         rc = EXIT_SUCCESS;
 138                         break;
 139                 }
 140
 141                 /* exit if queue is empty */
 142                 if (udev_queue_get_queue_is_empty(queue)) {
 143                         rc = EXIT_SUCCESS;
 144                         break;
 145                 }
 146
 147                 if (now(CLOCK_MONOTONIC) >= deadline)
 148                         break;
 149
 150                 /* wake up when queue is empty */
 151                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 152                         udev_queue_flush(queue);
 153         }
 154
 155 out:
 156         udev_queue_unref(queue);
 157         return rc;
 158 }
 159
 160 const struct udevadm_cmd udevadm_settle = {
 161         .name = "settle",
 162         .cmd = adm_settle,
 163         .help = "Wait for pending udev events",
 164 };