udev/udevsettle.c

   1 /*
   2  * Copyright (C) 2006 Kay Sievers <kay@vrfy.org>
   3  *
   4  *      This program is free software; you can redistribute it and/or modify it
   5  *      under the terms of the GNU General Public License as published by the
   6  *      Free Software Foundation version 2 of the License.
   7  *
   8  *      This program is distributed in the hope that it will be useful, but
   9  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  *      General Public License for more details.
  12  *
  13  *      You should have received a copy of the GNU General Public License along
  14  *      with this program; if not, write to the Free Software Foundation, Inc.,
  15  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16  *
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stddef.h>
  21 #include <string.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <dirent.h>
  26 #include <fcntl.h>
  27 #include <syslog.h>
  28 #include <getopt.h>
  29 #include <sys/stat.h>
  30 #include <sys/types.h>
  31
  32 #include "udev.h"
  33 #include "udevd.h"
  34
  35 #define DEFAULT_TIMEOUT                 180
  36 #define LOOP_PER_SECOND                 20
  37
  38 static void print_queue(const char *dir)
  39 {
  40         LIST_HEAD(files);
  41         struct name_entry *item;
  42
  43         if (add_matching_files(&files, dir, NULL) < 0)
  44                 return;
  45
  46         printf("\n\nAfter the udevadm settle timeout, the events queue contains:\n\n");
  47
  48         list_for_each_entry(item, &files, node) {
  49                 char target[NAME_SIZE];
  50                 size_t len;
  51                 const char *filename = strrchr(item->name, '/');
  52
  53                 if (filename == NULL)
  54                         continue;
  55                 filename++;
  56                 if (*filename == '\0')
  57                         continue;
  58
  59                 len = readlink(item->name, target, sizeof(target));
  60                 if (len < 0)
  61                         continue;
  62                 target[len] = '\0';
  63
  64                 printf("%s: %s\n", filename, target);
  65         }
  66
  67         printf("\n\n");
  68 }
  69
  70 int udevsettle(int argc, char *argv[], char *envp[])
  71 {
  72         char queuename[PATH_SIZE];
  73         char filename[PATH_SIZE];
  74         unsigned long long seq_kernel;
  75         unsigned long long seq_udev;
  76         char seqnum[32];
  77         int fd;
  78         ssize_t len;
  79         int timeout = DEFAULT_TIMEOUT;
  80         int loop;
  81         static const struct option options[] = {
  82                 { "timeout", 1, NULL, 't' },
  83                 { "help", 0, NULL, 'h' },
  84                 {}
  85         };
  86         int option;
  87         int rc = 1;
  88         int seconds;
  89
  90         logging_init("udevsettle");
  91         udev_config_init();
  92         dbg("version %s\n", UDEV_VERSION);
  93         sysfs_init();
  94
  95         while (1) {
  96                 option = getopt_long(argc, argv, "t:h", options, NULL);
  97                 if (option == -1)
  98                         break;
  99
 100                 switch (option) {
 101                 case 't':
 102                         seconds = atoi(optarg);
 103                         if (seconds > 0)
 104                                 timeout = seconds;
 105                         else
 106                                 fprintf(stderr, "invalid timeout value\n");
 107                         dbg("timeout=%i\n", timeout);
 108                         break;
 109                 case 'h':
 110                         printf("Usage: udevadm settle [--help] [--timeout=<seconds>]\n\n");
 111                         goto exit;
 112                 }
 113         }
 114
 115         strlcpy(queuename, udev_root, sizeof(queuename));
 116         strlcat(queuename, "/" EVENT_QUEUE_DIR, sizeof(queuename));
 117
 118         loop = timeout * LOOP_PER_SECOND;
 119         while (loop--) {
 120                 /* wait for events in queue to finish */
 121                 while (loop--) {
 122                         struct stat statbuf;
 123
 124                         if (stat(queuename, &statbuf) < 0) {
 125                                 info("queue is empty\n");
 126                                 break;
 127                         }
 128                         usleep(1000 * 1000 / LOOP_PER_SECOND);
 129                 }
 130                 if (loop <= 0) {
 131                         info("timeout waiting for queue\n");
 132                         print_queue(queuename);
 133                         goto exit;
 134                 }
 135
 136                 /* read current udev seqnum */
 137                 strlcpy(filename, udev_root, sizeof(filename));
 138                 strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 139                 fd = open(filename, O_RDONLY);
 140                 if (fd < 0)
 141                         goto exit;
 142                 len = read(fd, seqnum, sizeof(seqnum)-1);
 143                 close(fd);
 144                 if (len <= 0)
 145                         goto exit;
 146                 seqnum[len] = '\0';
 147                 seq_udev = strtoull(seqnum, NULL, 10);
 148                 info("udev seqnum = %llu\n", seq_udev);
 149
 150                 /* read current kernel seqnum */
 151                 strlcpy(filename, sysfs_path, sizeof(filename));
 152                 strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 153                 fd = open(filename, O_RDONLY);
 154                 if (fd < 0)
 155                         goto exit;
 156                 len = read(fd, seqnum, sizeof(seqnum)-1);
 157                 close(fd);
 158                 if (len <= 0)
 159                         goto exit;
 160                 seqnum[len] = '\0';
 161                 seq_kernel = strtoull(seqnum, NULL, 10);
 162                 info("kernel seqnum = %llu\n", seq_kernel);
 163
 164                 /* make sure all kernel events have arrived in the queue */
 165                 if (seq_udev >= seq_kernel) {
 166                         info("queue is empty and no pending events left\n");
 167                         rc = 0;
 168                         goto exit;
 169                 }
 170                 usleep(1000 * 1000 / LOOP_PER_SECOND);
 171                 info("queue is empty, but events still pending\n");
 172         }
 173
 174 exit:
 175         sysfs_cleanup();
 176         logging_close();
 177         return rc;
 178 }