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
  33 #include "udev_libc_wrapper.h"
  34 #include "udev.h"
  35 #include "logging.h"
  36 #include "udev_utils.h"
  37 #include "list.h"
  38
  39
  40 int pass_env_to_socket(const char *sockname, const char *devpath, const char *action)
  41 {
  42         int sock;
  43         struct sockaddr_un saddr;
  44         socklen_t addrlen;
  45         char buf[2048];
  46         size_t bufpos = 0;
  47         int i;
  48         int retval;
  49
  50         dbg("pass environment to socket '%s'", sockname);
  51         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  52         memset(&saddr, 0x00, sizeof(struct sockaddr_un));
  53         saddr.sun_family = AF_LOCAL;
  54         /* only abstract namespace is supported */
  55         strcpy(&saddr.sun_path[1], sockname);
  56         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
  57
  58         bufpos = snprintf(buf, sizeof(buf)-1, "%s@%s", action, devpath);
  59         bufpos++;
  60         for (i = 0; environ[i] != NULL && bufpos < sizeof(buf); i++) {
  61                 bufpos += strlcpy(&buf[bufpos], environ[i], sizeof(buf) - bufpos-1);
  62                 bufpos++;
  63         }
  64
  65         retval = sendto(sock, &buf, bufpos, 0, (struct sockaddr *)&saddr, addrlen);
  66         if (retval != -1)
  67                 retval = 0;
  68
  69         close(sock);
  70         return retval;
  71 }
  72
  73 int execute_program(const char *command, const char *subsystem,
  74                     char *result, size_t ressize, size_t *reslen)
  75 {
  76         int retval = 0;
  77         int count;
  78         int status;
  79         int pipefds[2];
  80         pid_t pid;
  81         char *pos;
  82         char arg[PATH_SIZE];
  83         char *argv[(sizeof(arg) / 2) + 1];
  84         int devnull;
  85         int i;
  86         size_t len;
  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         if (result) {
 115                 if (pipe(pipefds) != 0) {
 116                         err("pipe failed");
 117                         return -1;
 118                 }
 119         }
 120
 121         pid = fork();
 122         switch(pid) {
 123         case 0:
 124                 /* child dup2 write side of pipe to STDOUT */
 125                 devnull = open("/dev/null", O_RDWR);
 126                 if (devnull >= 0) {
 127                         dup2(devnull, STDIN_FILENO);
 128                         if (!result)
 129                                 dup2(devnull, STDOUT_FILENO);
 130                         dup2(devnull, STDERR_FILENO);
 131                         close(devnull);
 132                 }
 133                 if (result)
 134                         dup2(pipefds[1], STDOUT_FILENO);
 135                 execv(arg, argv);
 136                 err("exec of program failed");
 137                 _exit(1);
 138         case -1:
 139                 err("fork of '%s' failed", arg);
 140                 return -1;
 141         default:
 142                 /* parent reads from pipefds[0] */
 143                 if (result) {
 144                         close(pipefds[1]);
 145                         len = 0;
 146                         while (1) {
 147                                 count = read(pipefds[0], result + len, ressize - len-1);
 148                                 if (count < 0) {
 149                                         err("read failed with '%s'", strerror(errno));
 150                                         retval = -1;
 151                                         break;
 152                                 }
 153
 154                                 if (count == 0)
 155                                         break;
 156
 157                                 len += count;
 158                                 if (len >= ressize-1) {
 159                                         err("ressize %ld too short", (long)ressize);
 160                                         retval = -1;
 161                                         break;
 162                                 }
 163                         }
 164                         result[len] = '\0';
 165                         close(pipefds[0]);
 166                         if (reslen)
 167                                 *reslen = len;
 168                 }
 169                 waitpid(pid, &status, 0);
 170
 171                 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) {
 172                         dbg("exec program status 0x%x", status);
 173                         retval = -1;
 174                 }
 175         }
 176
 177         return retval;
 178 }
 179