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