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