udev_multiplex.c

   1 /*
   2  * udev_multiplex.c directory multiplexer
   3  *
   4  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   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
  11 /*
  12  * This essentially emulates the following shell script logic in C:
  13  *      DIR="/etc/dev.d"
  14  *      export DEVNAME="whatever_dev_name_udev_just_gave"
  15  *      for I in "${DIR}/$DEVNAME/"*.dev "${DIR}/$1/"*.dev "${DIR}/default/"*.dev ; do
  16  *              if [ -f $I ]; then $I $1 ; fi
  17  *      done
  18  *      exit 1;
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29
  30 #include "udev.h"
  31 #include "udev_utils.h"
  32 #include "logging.h"
  33
  34 static int run_program(struct udevice *udev, const char *filename)
  35 {
  36         pid_t pid;
  37         int fd;
  38
  39         dbg("running %s", filename);
  40
  41         pid = fork();
  42         switch (pid) {
  43         case 0:
  44                 /* child */
  45                 fd = open("/dev/null", O_RDWR);
  46                 if ( fd >= 0) {
  47                         dup2(fd, STDOUT_FILENO);
  48                         dup2(fd, STDIN_FILENO);
  49                         dup2(fd, STDERR_FILENO);
  50                 }
  51                 close(fd);
  52
  53                 execl(filename, filename, udev->subsystem, NULL);
  54                 dbg("exec of child failed");
  55                 _exit(1);
  56         case -1:
  57                 dbg("fork of child failed");
  58                 break;
  59                 return -1;
  60         default:
  61                 waitpid(pid, NULL, 0);
  62         }
  63
  64         return 0;
  65 }
  66
  67 /*
  68  * runs files in these directories in order:
  69  *      <node name given by udev>/
  70  *      subsystem/
  71  *      default/
  72  */
  73 void udev_multiplex_directory(struct udevice *udev, const char *basedir, const char *suffix)
  74 {
  75         char dirname[PATH_MAX];
  76
  77         /* chop the device name up into pieces based on '/' */
  78         if (udev->name[0] != '\0') {
  79                 char devname[NAME_SIZE];
  80                 char *temp;
  81
  82                 strfieldcpy(devname, udev->name);
  83                 temp = strchr(devname, '/');
  84                 while (temp != NULL) {
  85                         temp[0] = '\0';
  86
  87                         /* don't call the subsystem directory here */
  88                         if (strcmp(devname, udev->subsystem) != 0) {
  89                                 snprintf(dirname, PATH_MAX, "%s/%s", basedir, devname);
  90                                 dirname[PATH_MAX-1] = '\0';
  91                                 call_foreach_file(run_program, udev, dirname, suffix);
  92                         }
  93
  94                         temp[0] = '/';
  95                         ++temp;
  96                         temp = strchr(temp, '/');
  97                 }
  98         }
  99
 100         if (udev->name[0] != '\0') {
 101                 snprintf(dirname, PATH_MAX, "%s/%s", basedir, udev->name);
 102                 dirname[PATH_MAX-1] = '\0';
 103                 call_foreach_file(run_program, udev, dirname, suffix);
 104         }
 105
 106         if (udev->subsystem[0] != '\0') {
 107                 snprintf(dirname, PATH_MAX, "%s/%s", basedir, udev->subsystem);
 108                 dirname[PATH_MAX-1] = '\0';
 109                 call_foreach_file(run_program, udev, dirname, suffix);
 110         }
 111
 112         snprintf(dirname, PATH_MAX, "%s/default", basedir);
 113         dirname[PATH_MAX-1] = '\0';
 114         call_foreach_file(run_program, udev, dirname, suffix);
 115 }