src/udev/udevadm-settle.c

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Copyright © 2006-2009 Kay Sievers <kay@vrfy.org>
   4  * Copyright © 2009 Canonical Ltd.
   5  * Copyright © 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  */
   8
   9 #include <errno.h>
  10 #include <getopt.h>
  11 #include <poll.h>
  12 #include <stddef.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <unistd.h>
  17
  18 #include "parse-util.h"
  19 #include "udev.h"
  20 #include "udevadm-util.h"
  21 #include "util.h"
  22
  23 static void help(void) {
  24         printf("%s settle [OPTIONS]\n\n"
  25                "Wait for pending udev events.\n\n"
  26                "  -h --help                 Show this help\n"
  27                "  -V --version              Show package version\n"
  28                "  -t --timeout=SECONDS      Maximum time to wait for events\n"
  29                "  -E --exit-if-exists=FILE  Stop waiting if file exists\n"
  30                , program_invocation_short_name);
  31 }
  32
  33 static int adm_settle(struct udev *udev, int argc, char *argv[]) {
  34         static const struct option options[] = {
  35                 { "timeout",        required_argument, NULL, 't' },
  36                 { "exit-if-exists", required_argument, NULL, 'E' },
  37                 { "version",        no_argument,       NULL, 'V' },
  38                 { "help",           no_argument,       NULL, 'h' },
  39                 { "seq-start",      required_argument, NULL, 's' }, /* removed */
  40                 { "seq-end",        required_argument, NULL, 'e' }, /* removed */
  41                 { "quiet",          no_argument,       NULL, 'q' }, /* removed */
  42                 {}
  43         };
  44         usec_t deadline;
  45         const char *exists = NULL;
  46         unsigned int timeout = 120;
  47         struct pollfd pfd[1] = { {.fd = -1}, };
  48         int c;
  49         struct udev_queue *queue;
  50         int rc = EXIT_FAILURE;
  51
  52         while ((c = getopt_long(argc, argv, "t:E:Vhs:e:q", options, NULL)) >= 0) {
  53                 switch (c) {
  54
  55                 case 't': {
  56                         int r;
  57
  58                         r = safe_atou(optarg, &timeout);
  59                         if (r < 0) {
  60                                 log_error_errno(r, "Invalid timeout value '%s': %m", optarg);
  61                                 return EXIT_FAILURE;
  62                         }
  63                         break;
  64                 }
  65
  66                 case 'E':
  67                         exists = optarg;
  68                         break;
  69
  70                 case 'V':
  71                         print_version();
  72                         return EXIT_SUCCESS;
  73
  74                 case 'h':
  75                         help();
  76                         return EXIT_SUCCESS;
  77
  78                 case 's':
  79                 case 'e':
  80                 case 'q':
  81                         log_info("Option -%c no longer supported.", c);
  82                         return EXIT_FAILURE;
  83
  84                 case '?':
  85                         return EXIT_FAILURE;
  86
  87                 default:
  88                         assert_not_reached("Unknown argument");
  89                 }
  90         }
  91
  92         if (optind < argc) {
  93                 fprintf(stderr, "Extraneous argument: '%s'\n", argv[optind]);
  94                 return EXIT_FAILURE;
  95         }
  96
  97         deadline = now(CLOCK_MONOTONIC) + timeout * USEC_PER_SEC;
  98
  99         /* guarantee that the udev daemon isn't pre-processing */
 100         if (getuid() == 0) {
 101                 struct udev_ctrl *uctrl;
 102
 103                 uctrl = udev_ctrl_new(udev);
 104                 if (uctrl != NULL) {
 105                         if (udev_ctrl_send_ping(uctrl, MAX(5U, timeout)) < 0) {
 106                                 log_debug("no connection to daemon");
 107                                 udev_ctrl_unref(uctrl);
 108                                 return EXIT_SUCCESS;
 109                         }
 110                         udev_ctrl_unref(uctrl);
 111                 }
 112         }
 113
 114         queue = udev_queue_new(udev);
 115         if (!queue) {
 116                 log_error("unable to get udev queue");
 117                 return EXIT_FAILURE;
 118         }
 119
 120         pfd[0].events = POLLIN;
 121         pfd[0].fd = udev_queue_get_fd(queue);
 122         if (pfd[0].fd < 0) {
 123                 log_debug("queue is empty, nothing to watch");
 124                 rc = EXIT_SUCCESS;
 125                 goto out;
 126         }
 127
 128         for (;;) {
 129                 if (exists && access(exists, F_OK) >= 0) {
 130                         rc = EXIT_SUCCESS;
 131                         break;
 132                 }
 133
 134                 /* exit if queue is empty */
 135                 if (udev_queue_get_queue_is_empty(queue)) {
 136                         rc = EXIT_SUCCESS;
 137                         break;
 138                 }
 139
 140                 if (now(CLOCK_MONOTONIC) >= deadline)
 141                         break;
 142
 143                 /* wake up when queue is empty */
 144                 if (poll(pfd, 1, MSEC_PER_SEC) > 0 && pfd[0].revents & POLLIN)
 145                         udev_queue_flush(queue);
 146         }
 147
 148 out:
 149         udev_queue_unref(queue);
 150         return rc;
 151 }
 152
 153 const struct udevadm_cmd udevadm_settle = {
 154         .name = "settle",
 155         .cmd = adm_settle,
 156         .help = "Wait for pending udev events",
 157 };