udev_utils_run.c

   1 /*
   2  * udev_utils_run.c - execute programs from udev and read its output
   3  *
   4  * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@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
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <stddef.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <ctype.h>
  29 #include <sys/socket.h>
  30 #include <sys/un.h>
  31 #include <sys/wait.h>
  32 #include <sys/select.h>
  33
  34 #include "udev.h"
  35
  36 extern char **environ;
  37
  38 int pass_env_to_socket(const char *sockname, const char *devpath, const char *action)
  39 {
  40         int sock;
  41         struct sockaddr_un saddr;
  42         socklen_t addrlen;
  43         char buf[2048];
  44         size_t bufpos = 0;
  45         int i;
  46         ssize_t count;
  47         int retval = 0;
  48
  49         dbg("pass environment to socket '%s'", sockname);
  50         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  51         memset(&saddr, 0x00, sizeof(struct sockaddr_un));
  52         saddr.sun_family = AF_LOCAL;
  53         /* abstract namespace only */
  54         strcpy(&saddr.sun_path[1], sockname);
  55         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
  56
  57         bufpos = snprintf(buf, sizeof(buf)-1, "%s@%s", action, devpath);
  58         bufpos++;
  59         for (i = 0; environ[i] != NULL && bufpos < sizeof(buf); i++) {
  60                 bufpos += strlcpy(&buf[bufpos], environ[i], sizeof(buf) - bufpos-1);
  61                 bufpos++;
  62         }
  63
  64         count = sendto(sock, &buf, bufpos, 0, (struct sockaddr *)&saddr, addrlen);
  65         if (count < 0)
  66                 retval = -1;
  67         info("passed %zi bytes to socket '%s', ", count, sockname);
  68
  69         close(sock);
  70         return retval;
  71 }
  72
  73 int run_program(const char *command, const char *subsystem,
  74                 char *result, size_t ressize, size_t *reslen, int log)
  75 {
  76         int retval = 0;
  77         int status;
  78         int outpipe[2] = {-1, -1};
  79         int errpipe[2] = {-1, -1};
  80         pid_t pid;
  81         char arg[PATH_SIZE];
  82         char program[PATH_SIZE];
  83         char *argv[(sizeof(arg) / 2) + 1];
  84         int devnull;
  85         int i;
  86
  87         /* build argv from comand */
  88         strlcpy(arg, command, sizeof(arg));
  89         i = 0;
  90         if (strchr(arg, ' ') != NULL) {
  91                 char *pos = arg;
  92
  93                 while (pos != NULL) {
  94                         if (pos[0] == '\'') {
  95                                 /* don't separate if in apostrophes */
  96                                 pos++;
  97                                 argv[i] = strsep(&pos, "\'");
  98                                 while (pos != NULL && pos[0] == ' ')
  99                                         pos++;
 100                         } else {
 101                                 argv[i] = strsep(&pos, " ");
 102                         }
 103                         dbg("arg[%i] '%s'", i, argv[i]);
 104                         i++;
 105                 }
 106                 argv[i] = NULL;
 107         } else {
 108                 argv[0] = arg;
 109                 argv[1] = NULL;
 110         }
 111         info("'%s'", command);
 112
 113         /* prepare pipes from child to parent */
 114         if (result || log) {
 115                 if (pipe(outpipe) != 0) {
 116                         err("pipe failed: %s", strerror(errno));
 117                         return -1;
 118                 }
 119         }
 120         if (log) {
 121                 if (pipe(errpipe) != 0) {
 122                         err("pipe failed: %s", strerror(errno));
 123                         return -1;
 124                 }
 125         }
 126
 127         /* allow programs in /lib/udev called without the path */
 128         if (strchr(argv[0], '/') == NULL) {
 129                 strlcpy(program, "/lib/udev/", sizeof(program));
 130                 strlcat(program, argv[0], sizeof(program));
 131                 argv[0] = program;
 132         }
 133
 134         pid = fork();
 135         switch(pid) {
 136         case 0:
 137                 /* child closes parent ends of pipes */
 138                 if (outpipe[READ_END] > 0)
 139                         close(outpipe[READ_END]);
 140                 if (errpipe[READ_END] > 0)
 141                         close(errpipe[READ_END]);
 142
 143                 /* discard child output or connect to pipe */
 144                 devnull = open("/dev/null", O_RDWR);
 145                 if (devnull > 0) {
 146                         dup2(devnull, STDIN_FILENO);
 147                         if (outpipe[WRITE_END] < 0)
 148                                 dup2(devnull, STDOUT_FILENO);
 149                         if (errpipe[WRITE_END] < 0)
 150                                 dup2(devnull, STDERR_FILENO);
 151                         close(devnull);
 152                 } else
 153                         err("open /dev/null failed: %s", strerror(errno));
 154                 if (outpipe[WRITE_END] > 0)
 155                         dup2(outpipe[WRITE_END], STDOUT_FILENO);
 156                 if (errpipe[WRITE_END] > 0)
 157                         dup2(errpipe[WRITE_END], STDERR_FILENO);
 158                 execv(argv[0], argv);
 159
 160                 /* we should never reach this */
 161                 err("exec of program '%s' failed", argv[0]);
 162                 _exit(1);
 163         case -1:
 164                 err("fork of '%s' failed: %s", argv[0], strerror(errno));
 165                 return -1;
 166         default:
 167                 /* read from child if requested */
 168                 if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 169                         ssize_t count;
 170                         size_t respos = 0;
 171
 172                         /* parent closes child ends of pipes */
 173                         if (outpipe[WRITE_END] > 0)
 174                                 close(outpipe[WRITE_END]);
 175                         if (errpipe[WRITE_END] > 0)
 176                                 close(errpipe[WRITE_END]);
 177
 178                         /* read child output */
 179                         while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
 180                                 int fdcount;
 181                                 fd_set readfds;
 182
 183                                 FD_ZERO(&readfds);
 184                                 if (outpipe[READ_END] > 0)
 185                                         FD_SET(outpipe[READ_END], &readfds);
 186                                 if (errpipe[READ_END] > 0)
 187                                         FD_SET(errpipe[READ_END], &readfds);
 188                                 fdcount = select(UDEV_MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
 189                                 if (fdcount < 0) {
 190                                         if (errno == EINTR)
 191                                                 continue;
 192                                         retval = -1;
 193                                         break;
 194                                 }
 195
 196                                 /* get stdout */
 197                                 if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
 198                                         char inbuf[1024];
 199                                         char *pos;
 200                                         char *line;
 201
 202                                         count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
 203                                         if (count <= 0) {
 204                                                 close(outpipe[READ_END]);
 205                                                 outpipe[READ_END] = -1;
 206                                                 if (count < 0) {
 207                                                         err("stdin read failed: %s", strerror(errno));
 208                                                         retval = -1;
 209                                                 }
 210                                                 continue;
 211                                         }
 212                                         inbuf[count] = '\0';
 213
 214                                         /* store result for rule processing */
 215                                         if (result) {
 216                                                 if (respos + count < ressize) {
 217                                                         memcpy(&result[respos], inbuf, count);
 218                                                         respos += count;
 219                                                 } else {
 220                                                         err("ressize %ld too short", (long)ressize);
 221                                                         retval = -1;
 222                                                 }
 223                                         }
 224                                         pos = inbuf;
 225                                         while ((line = strsep(&pos, "\n")))
 226                                                 if (pos || line[0] != '\0')
 227                                                         info("'%s' (stdout) '%s'", argv[0], line);
 228                                 }
 229
 230                                 /* get stderr */
 231                                 if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
 232                                         char errbuf[1024];
 233                                         char *pos;
 234                                         char *line;
 235
 236                                         count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
 237                                         if (count <= 0) {
 238                                                 close(errpipe[READ_END]);
 239                                                 errpipe[READ_END] = -1;
 240                                                 if (count < 0)
 241                                                         err("stderr read failed: %s", strerror(errno));
 242                                                 continue;
 243                                         }
 244                                         errbuf[count] = '\0';
 245                                         pos = errbuf;
 246                                         while ((line = strsep(&pos, "\n")))
 247                                                 if (pos || line[0] != '\0')
 248                                                         info("'%s' (stderr) '%s'", argv[0], line);
 249                                 }
 250                         }
 251                         if (outpipe[READ_END] > 0)
 252                                 close(outpipe[READ_END]);
 253                         if (errpipe[READ_END] > 0)
 254                                 close(errpipe[READ_END]);
 255
 256                         /* return the childs stdout string */
 257                         if (result) {
 258                                 result[respos] = '\0';
 259                                 dbg("result='%s'", result);
 260                                 if (reslen)
 261                                         *reslen = respos;
 262                         }
 263                 }
 264                 waitpid(pid, &status, 0);
 265                 if (WIFEXITED(status)) {
 266                         info("'%s' returned with status %i", argv[0], WEXITSTATUS(status));
 267                         if (WEXITSTATUS(status) != 0)
 268                                 retval = -1;
 269                 } else {
 270                         err("'%s' abnormal exit", argv[0]);
 271                         retval = -1;
 272                 }
 273         }
 274
 275         return retval;
 276 }