udevsettle.c

   1 /*
   2  * udevsettle.c
   3  *
   4  * Copyright (C) 2006 Kay Sievers <kay@vrfy.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  *
  10  *      This program is distributed in the hope that it will be useful, but
  11  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *      General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License along
  16  *      with this program; if not, write to the Free Software Foundation, Inc.,
  17  *      675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <string.h>
  24 #include <stdio.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <dirent.h>
  28 #include <fcntl.h>
  29 #include <syslog.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32
  33 #include "udev.h"
  34 #include "udevd.h"
  35
  36 #define LOOP_PER_SECOND                 20
  37
  38 static const char *udev_log_str;
  39
  40 #ifdef USE_LOG
  41 void log_message(int priority, const char *format, ...)
  42 {
  43         va_list args;
  44
  45         if (priority > udev_log_priority)
  46                 return;
  47
  48         va_start(args, format);
  49         vsyslog(priority, format, args);
  50         va_end(args);
  51 }
  52 #endif
  53
  54 int main(int argc, char *argv[], char *envp[])
  55 {
  56         char queuename[PATH_SIZE];
  57         char filename[PATH_SIZE];
  58         unsigned long long seq_kernel;
  59         unsigned long long seq_udev;
  60         char seqnum[32];
  61         int fd;
  62         ssize_t len;
  63         int timeout = 30;
  64         int loop;
  65         int i;
  66         int rc = 1;
  67
  68         logging_init("udevsettle");
  69         udev_config_init();
  70         dbg("version %s", UDEV_VERSION);
  71
  72         udev_log_str = getenv("UDEV_LOG");
  73
  74         for (i = 1 ; i < argc; i++) {
  75                 char *arg = argv[i];
  76
  77                 if (strncmp(arg, "--timeout=", 10) == 0) {
  78                         char *str = &arg[10];
  79
  80                         timeout = atoi(str);
  81                         dbg("timeout=%i", timeout);
  82                         if (timeout <= 0) {
  83                                 fprintf(stderr, "Invalid timeout value.\n");
  84                                 goto exit;
  85                         }
  86                 } else {
  87                         fprintf(stderr, "Usage: udevsettle [--timeout=<seconds>]\n");
  88                         goto exit;
  89                 }
  90         }
  91
  92         sysfs_init();
  93         strlcpy(queuename, udev_root, sizeof(queuename));
  94         strlcat(queuename, "/" EVENT_QUEUE_DIR, sizeof(queuename));
  95
  96         loop = timeout * LOOP_PER_SECOND;
  97         while (loop--) {
  98                 /* wait for events in queue to finish */
  99                 while (loop--) {
 100                         struct stat statbuf;
 101
 102                         if (stat(queuename, &statbuf) < 0) {
 103                                 info("queue is empty");
 104                                 break;
 105                         }
 106                         usleep(1000 * 1000 / LOOP_PER_SECOND);
 107                 }
 108                 if (loop <= 0) {
 109                         info("timeout waiting for queue");
 110                         goto exit;
 111                 }
 112
 113                 /* read current kernel seqnum */
 114                 strlcpy(filename, sysfs_path, sizeof(filename));
 115                 strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 116                 fd = open(filename, O_RDONLY);
 117                 if (fd < 0)
 118                         goto exit;
 119                 len = read(fd, seqnum, sizeof(seqnum)-1);
 120                 close(fd);
 121                 if (len <= 0)
 122                         goto exit;
 123                 seqnum[len] = '\0';
 124                 seq_kernel = strtoull(seqnum, NULL, 10);
 125                 info("kernel seqnum = %llu", seq_kernel);
 126
 127                 /* read current udev seqnum */
 128                 strlcpy(filename, udev_root, sizeof(filename));
 129                 strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 130                 fd = open(filename, O_RDONLY);
 131                 if (fd < 0)
 132                         goto exit;
 133                 len = read(fd, seqnum, sizeof(seqnum)-1);
 134                 close(fd);
 135                 if (len <= 0)
 136                         goto exit;
 137                 seqnum[len] = '\0';
 138                 seq_udev = strtoull(seqnum, NULL, 10);
 139                 info("udev seqnum = %llu", seq_udev);
 140
 141                 /* make sure all kernel events have arrived in the queue */
 142                 if (seq_udev >= seq_kernel) {
 143                         info("queue is empty and no pending events left");
 144                         rc = 0;
 145                         goto exit;
 146                 }
 147                 usleep(1000 * 1000 / LOOP_PER_SECOND);
 148                 info("queue is empty, but events still pending");
 149         }
 150
 151 exit:
 152         sysfs_cleanup();
 153         logging_close();
 154         return rc;
 155 }