libmultipath/callout.c

   1 /*
   2  * Source: copy of the udev package source file
   3  *
   4  * Copyrights of the source file apply
   5  * Copyright (c) 2004 Christophe Varoqui
   6  */
   7 #include <stdio.h>
   8 #include <sys/stat.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <sys/types.h>
  12 #include <stdlib.h>
  13 #include <sys/wait.h>
  14 #include <errno.h>
  15
  16 #define PROGRAM_SIZE    100
  17 #define FIELD_PROGRAM
  18
  19 #define strfieldcpy(to, from) \
  20 do { \
  21         to[sizeof(to)-1] = '\0'; \
  22         strncpy(to, from, sizeof(to)-1); \
  23 } while (0)
  24
  25 int execute_program(char *path, char *value, int len)
  26 {
  27         int retval;
  28         int count;
  29         int status;
  30         int fds[2];
  31         pid_t pid;
  32         char *pos;
  33         char arg[PROGRAM_SIZE];
  34         char *argv[sizeof(arg) / 2];
  35         int i;
  36
  37         i = 0;
  38
  39         if (strchr(path, ' ')) {
  40                 strfieldcpy(arg, path);
  41                 pos = arg;
  42                 while (pos != NULL) {
  43                         if (pos[0] == '\'') {
  44                                 /* don't separate if in apostrophes */
  45                                 pos++;
  46                                 argv[i] = strsep(&pos, "\'");
  47                                 while (pos[0] == ' ')
  48                                         pos++;
  49                         } else {
  50                                 argv[i] = strsep(&pos, " ");
  51                         }
  52                         i++;
  53                 }
  54         } else {
  55                 argv[i++] = path;
  56         }
  57         argv[i] =  NULL;
  58
  59         retval = pipe(fds);
  60
  61         if (retval != 0)
  62                 return -1;
  63
  64
  65         pid = fork();
  66
  67         switch(pid) {
  68         case 0:
  69                 /* child */
  70                 close(STDOUT_FILENO);
  71
  72                 /* dup write side of pipe to STDOUT */
  73                 dup(fds[1]);
  74
  75                 retval = execv(argv[0], argv);
  76
  77                 exit(-1);
  78         case -1:
  79                 return -1;
  80         default:
  81                 /* parent reads from fds[0] */
  82                 close(fds[1]);
  83                 retval = 0;
  84                 i = 0;
  85                 while (1) {
  86                         count = read(fds[0], value + i, len - i-1);
  87                         if (count <= 0)
  88                                 break;
  89
  90                         i += count;
  91                         if (i >= len-1) {
  92                                 retval = -1;
  93                                 break;
  94                         }
  95                 }
  96
  97                 if (count < 0)
  98                         retval = -1;
  99
 100                 if (i > 0 && value[i-1] == '\n')
 101                         i--;
 102                 value[i] = '\0';
 103
 104                 wait(&status);
 105                 close(fds[0]);
 106
 107                 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
 108                         retval = -1;
 109         }
 110         return retval;
 111 }