BSD 4_3_Net_2 development

[unix-history] / usr / src / contrib / isode / dirent / opendir.c

/*
       opendir -- open a directory stream

       last edit:      16-Jun-1987     D A Gwyn
*/

#include        <sys/errno.h>
#include        <sys/types.h>
#include        <sys/stat.h>
#include        "usr.dirent.h"

#ifndef GETDENTS
#ifdef BSD_SYSV
#define open    _open                   /* avoid emulation overhead */
#endif

typedef char    *pointer;               /* (void *) if you have it */

extern void     free();
extern pointer  malloc();
extern int      open(), close(), fstat();

extern int      errno;

#ifndef NULL
#define NULL    0
#endif

#ifndef O_RDONLY
#define O_RDONLY        0
#endif

#ifndef S_ISDIR                         /* macro to test for directory file */
#define S_ISDIR( mode )         (((mode) & S_IFMT) == S_IFDIR)
#endif

DIR *
opendir( dirname )
       char            *dirname;       /* name of directory */
       {
       register DIR    *dirp;          /* -> malloc'ed storage */
       register int    fd;             /* file descriptor for read */
       struct stat     sbuf;           /* result of fstat() */

       if ( (fd = open( dirname, O_RDONLY )) < 0 )
               return NULL;            /* errno set by open() */

       if ( fstat( fd, &sbuf ) != 0 || !S_ISDIR( sbuf.st_mode ) )
               {
               (void)close( fd );
               errno = ENOTDIR;
               return NULL;            /* not a directory */
               }

       if ( (dirp = (DIR *)malloc( sizeof(DIR) )) == NULL
         || (dirp->dd_buf = (char *)malloc( (unsigned)DIRBUF )) == NULL
          )    {
               register int    serrno = errno;
                                       /* errno set to ENOMEM by sbrk() */

               if ( dirp != NULL )
                       free( (pointer)dirp );

               (void)close( fd );
               errno = serrno;
               return NULL;            /* not enough memory */
               }

       dirp->dd_fd = fd;
       dirp->dd_loc = dirp->dd_size = 0;       /* refill needed */

       return dirp;
       }
#else
int     _opendir_stub () {};
#endif