newlib/libc/posix/execvp.c

   1 #ifndef _NO_EXECVE
   2
   3 /* execvp.c */
   4
   5 /* This and the other exec*.c files in this directory require
   6    the target to provide the _execve syscall.  */
   7
   8 #include <_ansi.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <dirent.h>
  12 #include <string.h>
  13 #include <errno.h>
  14 #include <ctype.h>
  15
  16 #define PATH_DELIM ':'
  17
  18 /*
  19  * Copy string, until c or <nul> is encountered.
  20  * NUL-terminate the destination string (s1).
  21  */
  22
  23 static char *
  24 strccpy (char *s1,
  25         char *s2,
  26         char c)
  27 {
  28   char *dest = s1;
  29
  30   while (*s2 && *s2 != c)
  31     *s1++ = *s2++;
  32   *s1 = 0;
  33
  34   return dest;
  35 }
  36
  37 int
  38 execvp (const char *file,
  39         char * const argv[])
  40 {
  41   char *path = getenv ("PATH");
  42   char buf[MAXNAMLEN];
  43
  44   /* If $PATH doesn't exist, just pass FILE on unchanged.  */
  45   if (!path)
  46     return execv (file, argv);
  47
  48   /* If FILE contains a directory, don't search $PATH.  */
  49   if (strchr (file, '/')
  50       )
  51     return execv (file, argv);
  52
  53   while (*path)
  54     {
  55       strccpy (buf, path, PATH_DELIM);
  56       /* An empty entry means the current directory.  */
  57       if (*buf != 0 && buf[strlen(buf) - 1] != '/')
  58         strcat (buf, "/");
  59       strcat (buf, file);
  60       if (execv (buf, argv) == -1 && errno != ENOENT)
  61         return -1;
  62       while (*path && *path != PATH_DELIM)
  63         path++;
  64       if (*path == PATH_DELIM)
  65         path++;                 /* skip over delim */
  66     }
  67
  68   return -1;
  69 }
  70
  71 #endif /* !_NO_EXECVE  */