lib/libc/posix/_opendir.c

   1 /*      opendir()                                       Author: Kees J. Bot
   2  *                                                              24 Apr 1989
   3  */
   4 #define nil 0
   5 #include <lib.h>
   6 #define close   _close
   7 #define fcntl   _fcntl
   8 #define fstat   _fstat
   9 #define open    _open
  10 #define opendir _opendir
  11 #define stat    _stat
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <dirent.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19
  20 DIR *opendir(const char *name)
  21 /* Open a directory for reading. */
  22 {
  23         int d, f;
  24         DIR *dp;
  25         struct stat st;
  26
  27         /* Only read directories. */
  28         if (stat(name, &st) < 0) return nil;
  29         if (!S_ISDIR(st.st_mode)) { errno= ENOTDIR; return nil; }
  30
  31         if ((d= open(name, O_RDONLY | O_NONBLOCK)) < 0) return nil;
  32
  33         /* Check the type again, mark close-on-exec, get a buffer. */
  34         if (fstat(d, &st) < 0
  35                 || (errno= ENOTDIR, !S_ISDIR(st.st_mode))
  36                 || (f= fcntl(d, F_GETFD)) < 0
  37                 || fcntl(d, F_SETFD, f | FD_CLOEXEC) < 0
  38                 || (dp= (DIR *) malloc(sizeof(*dp))) == nil
  39         ) {
  40                 int err= errno;
  41                 (void) close(d);
  42                 errno= err;
  43                 return nil;
  44         }
  45
  46         dp->_fd= d;
  47         dp->_count= 0;
  48         dp->_pos= 0;
  49
  50         return dp;
  51 }
  52