xref: /csrg-svn/lib/libc/gen/opendir.c (revision 62736)
121350Sdist /*
2*62736Sbostic  * Copyright (c) 1983, 1993
3*62736Sbostic  *	The Regents of the University of California.  All rights reserved.
434790Sbostic  *
542625Sbostic  * %sccs.include.redist.c%
621350Sdist  */
721350Sdist 
826573Sdonn #if defined(LIBC_SCCS) && !defined(lint)
9*62736Sbostic static char sccsid[] = "@(#)opendir.c	8.1 (Berkeley) 06/08/93";
1034790Sbostic #endif /* LIBC_SCCS and not lint */
115750Smckusick 
129142Smckusick #include <sys/param.h>
1336545Smckusick #include <dirent.h>
1438664Smckusick #include <fcntl.h>
1546597Sdonn #include <stdlib.h>
1646597Sdonn #include <unistd.h>
175750Smckusick 
185750Smckusick /*
195750Smckusick  * open a directory.
205750Smckusick  */
215750Smckusick DIR *
225750Smckusick opendir(name)
2346597Sdonn 	const char *name;
245750Smckusick {
256097Smckusic 	register DIR *dirp;
267659Smckusick 	register int fd;
275750Smckusick 
287659Smckusick 	if ((fd = open(name, 0)) == -1)
295750Smckusick 		return NULL;
3057854Sralph 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
3138664Smckusick 	    (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
327659Smckusick 		close (fd);
336097Smckusic 		return NULL;
346097Smckusic 	}
3538435Smckusick 	/*
3652940Sralph 	 * If CLBYTES is an exact multiple of DIRBLKSIZ, use a CLBYTES
3738435Smckusick 	 * buffer that it cluster boundary aligned.
3838435Smckusick 	 * Hopefully this can be a big win someday by allowing page trades
3938435Smckusick 	 * to user space to be done by getdirentries()
4038435Smckusick 	 */
4152940Sralph 	if ((CLBYTES % DIRBLKSIZ) == 0) {
4252940Sralph 		dirp->dd_buf = malloc(CLBYTES);
4352940Sralph 		dirp->dd_len = CLBYTES;
4438435Smckusick 	} else {
4538435Smckusick 		dirp->dd_buf = malloc(DIRBLKSIZ);
4638435Smckusick 		dirp->dd_len = DIRBLKSIZ;
4738435Smckusick 	}
4838435Smckusick 	if (dirp->dd_buf == NULL) {
4938435Smckusick 		close (fd);
5038435Smckusick 		return NULL;
5138435Smckusick 	}
527659Smckusick 	dirp->dd_fd = fd;
535750Smckusick 	dirp->dd_loc = 0;
5438435Smckusick 	dirp->dd_seek = 0;
5539957Smckusick 	/*
5639957Smckusick 	 * Set up seek point for rewinddir.
5739957Smckusick 	 */
5862720Smckusick 	dirp->dd_rewind = telldir(dirp);
595750Smckusick 	return dirp;
605750Smckusick }
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