udevstart.c

   1 /*
   2  * udevstart.c
   3  *
   4  * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5  *
   6  * Quick and dirty way to populate a /dev with udev if your system
   7  * does not have access to a shell.  Based originally on a patch to udev
   8  * from Harald Hoyer <harald@redhat.com>
   9  *
  10  *      This program is free software; you can redistribute it and/or modify it
  11  *      under the terms of the GNU General Public License as published by the
  12  *      Free Software Foundation version 2 of the License.
  13  *
  14  *      This program is distributed in the hope that it will be useful, but
  15  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *      General Public License for more details.
  18  *
  19  *      You should have received a copy of the GNU General Public License along
  20  *      with this program; if not, write to the Free Software Foundation, Inc.,
  21  *      675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  */
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <ctype.h>
  30 #include <signal.h>
  31 #include <dirent.h>
  32 #include <sys/wait.h>
  33
  34 #include "logging.h"
  35
  36
  37 #ifdef LOG
  38 unsigned char logname[42];
  39 void log_message(int level, const char *format, ...)
  40 {
  41         va_list args;
  42
  43         va_start(args, format);
  44         vsyslog(level, format, args);
  45         va_end(args);
  46 }
  47 #endif
  48
  49
  50 #define MAX_PATHLEN     1024
  51 #define SYSBLOCK        "/sys/block"
  52 #define SYSCLASS        "/sys/class"
  53
  54 static int execute_udev(char *path, char *value, int len)
  55 {
  56         int retval;
  57         int res;
  58         int status;
  59         int fds[2];
  60         pid_t pid;
  61         int value_set = 0;
  62         char buffer[255];
  63         char *pos;
  64
  65         retval = pipe(fds);
  66         if (retval != 0) {
  67                 dbg("pipe failed");
  68                 return -1;
  69         }
  70         pid = fork();
  71         switch(pid) {
  72         case 0:
  73                 /* child */
  74                 close(STDOUT_FILENO);
  75
  76                 /* dup write side of pipe to STDOUT */
  77                 dup(fds[1]);
  78
  79                 dbg("executing /sbin/udev '%s'", path);
  80                 retval = execl("/sbin/udev", "/sbin/udev", path, NULL);
  81
  82                 info("execution of '%s' failed", path);
  83                 exit(1);
  84         case -1:
  85                 dbg("fork failed");
  86                 return -1;
  87         default:
  88                 /* parent reads from fds[0] */
  89                 close(fds[1]);
  90                 retval = 0;
  91                 while (1) {
  92                         res = read(fds[0], buffer, sizeof(buffer) - 1);
  93                         if (res <= 0)
  94                                 break;
  95                         buffer[res] = '\0';
  96                         if (res > len) {
  97                                 dbg("result len %d too short", len);
  98                                 retval = -1;
  99                         }
 100                         if (value_set) {
 101                                 dbg("result value already set");
 102                                 retval = -1;
 103                         } else {
 104                                 value_set = 1;
 105                                 strncpy(value, buffer, len);
 106                                 pos = value + strlen(value)-1;
 107                                 if (pos[0] == '\n')
 108                                         pos[0] = '\0';
 109                                 dbg("result is '%s'", value);
 110                         }
 111                 }
 112                 close(fds[0]);
 113                 res = wait(&status);
 114                 if (res < 0) {
 115                         dbg("wait failed result %d", res);
 116                         retval = -1;
 117                 }
 118
 119                 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) {
 120                         dbg("exec program status 0x%x", status);
 121                         retval = -1;
 122                 }
 123         }
 124         return retval;
 125 }
 126
 127 static int udev_scan(void)
 128 {
 129         char           *devpath;
 130         DIR            *dir;
 131         struct dirent  *dent;
 132         int             retval = -EINVAL;
 133         char scratch[200];
 134
 135         devpath = "block";
 136         dir = opendir(SYSBLOCK);
 137         if (dir) {
 138                 for (dent = readdir(dir); dent; dent = readdir(dir)) {
 139                         char            dirname[MAX_PATHLEN];
 140                         DIR            *dir2;
 141                         struct dirent  *dent2;
 142                         if ((strcmp(dent->d_name, ".") == 0)
 143                             || (strcmp(dent->d_name, "..") == 0))
 144                                 continue;
 145
 146                         snprintf(dirname, MAX_PATHLEN, "/block/%s", dent->d_name);
 147
 148                         setenv("DEVPATH", dirname, 1);
 149                         dbg("udev block, 'DEVPATH' = '%s'", dirname);
 150                         execute_udev("block", scratch, sizeof(scratch));
 151
 152                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSBLOCK, dent->d_name);
 153
 154                         dir2 = opendir(dirname);
 155                         if (dir2) {
 156                                 for (dent2 = readdir(dir2); dent2; dent2 = readdir(dir2)) {
 157                                         char            dirname2[MAX_PATHLEN];
 158                                         DIR            *dir3;
 159                                         struct dirent  *dent3;
 160
 161                                         if ((strcmp(dent2->d_name, ".") == 0) ||
 162                                             (strcmp(dent2->d_name, "..") == 0))
 163                                                 continue;
 164
 165                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 166
 167                                         dir3 = opendir(dirname2);
 168                                         if (dir3) {
 169                                                 for (dent3 = readdir(dir3); dent3; dent3 = readdir(dir3)) {
 170                                                         char filename[MAX_PATHLEN];
 171
 172                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 173                                                                 snprintf(filename, MAX_PATHLEN, "/block/%s/%s", dent->d_name, dent2->d_name);
 174                                                                 setenv("DEVPATH", filename, 1);
 175                                                                 dbg("udev block, 'DEVPATH' = '%s'", filename);
 176                                                                 execute_udev("block", scratch, sizeof(scratch));
 177                                                         }
 178                                                 }
 179                                         }
 180                                 }
 181                         }
 182                 }
 183         }
 184
 185         devpath = "class";
 186         dir = opendir(SYSCLASS);
 187         if (dir) {
 188                 for (dent = readdir(dir); dent; dent = readdir(dir)) {
 189                         char            dirname[MAX_PATHLEN];
 190                         DIR            *dir2;
 191                         struct dirent  *dent2;
 192                         if ((strcmp(dent->d_name, ".") == 0)
 193                             || (strcmp(dent->d_name, "..") == 0))
 194                                 continue;
 195
 196                         snprintf(dirname, MAX_PATHLEN, "%s/%s", SYSCLASS, dent->d_name);
 197
 198                         dir2 = opendir(dirname);
 199                         if (dir2) {
 200                                 for (dent2 = readdir(dir2); dent2; dent2 = readdir(dir2)) {
 201                                         char            dirname2[MAX_PATHLEN];
 202                                         DIR            *dir3;
 203                                         struct dirent  *dent3;
 204
 205                                         if ((strcmp(dent2->d_name, ".") == 0) || (strcmp(dent2->d_name, "..") == 0))
 206                                                 continue;
 207
 208                                         snprintf(dirname2, MAX_PATHLEN, "%s/%s", dirname, dent2->d_name);
 209
 210                                         dir3 = opendir(dirname2);
 211                                         if (dir3) {
 212                                                 for (dent3 = readdir(dir3); dent3; dent3 = readdir(dir3)) {
 213                                                         char
 214                                                                         filename[MAX_PATHLEN];
 215
 216                                                         if (strcmp(dent3->d_name, "dev") == 0) {
 217                                                                 snprintf
 218                                                                     (filename,
 219                                                                      MAX_PATHLEN,
 220                                                                      "/class/%s/%s", dent->d_name, dent2->d_name);
 221                                                                 setenv("DEVPATH", filename, 1);
 222                                                                 dbg("udev '%s', 'DEVPATH' = '%s'", dent->d_name, filename);
 223                                                                 execute_udev(dent->d_name, scratch, sizeof(scratch));
 224                                                         }
 225                                                 }
 226                                         }
 227                                 }
 228                         }
 229                 }
 230         }
 231
 232         if (retval > 0)
 233                 retval = 0;
 234
 235         return -retval;
 236 }
 237
 238
 239 int main(int argc, char **argv, char **envp)
 240 {
 241         init_logging("udevstart");
 242
 243         setenv("ACTION", "add", 1);
 244         setenv("UDEV_NO_SLEEP", "1", 1);
 245
 246         return udev_scan();
 247 }