src/process/execvp.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include <limits.h>
   6 #include "libc.h"
   7
   8 extern char **__environ;
   9
  10 int __execvpe(const char *file, char *const argv[], char *const envp[])
  11 {
  12         const char *p, *z, *path = getenv("PATH");
  13         size_t l, k;
  14         int seen_eacces = 0;
  15
  16         errno = ENOENT;
  17         if (!*file) return -1;
  18
  19         if (strchr(file, '/'))
  20                 return execve(file, argv, envp);
  21
  22         if (!path) path = "/usr/local/bin:/bin:/usr/bin";
  23         k = strnlen(file, NAME_MAX+1);
  24         if (k > NAME_MAX) {
  25                 errno = ENAMETOOLONG;
  26                 return -1;
  27         }
  28         l = strnlen(path, PATH_MAX-1)+1;
  29
  30         for(p=path; ; p=z) {
  31                 char b[l+k+1];
  32                 z = strchr(p, ':');
  33                 if (!z) z = p+strlen(p);
  34                 if (z-p >= l) {
  35                         if (!*z++) break;
  36                         continue;
  37                 }
  38                 memcpy(b, p, z-p);
  39                 b[z-p] = '/';
  40                 memcpy(b+(z-p)+(z>p), file, k+1);
  41                 execve(b, argv, envp);
  42                 switch (errno) {
  43                 case EACCES:
  44                         seen_eacces = 1;
  45                 case ENOENT:
  46                 case ENOTDIR:
  47                         break;
  48                 default:
  49                         return -1;
  50                 }
  51                 if (!*z++) break;
  52         }
  53         if (seen_eacces) errno = EACCES;
  54         return -1;
  55 }
  56
  57 int execvp(const char *file, char *const argv[])
  58 {
  59         return __execvpe(file, argv, __environ);
  60 }
  61
  62 weak_alias(__execvpe, execvpe);