libmultipath/callout.c

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