xref: /titanic_41/usr/src/lib/libast/common/dir/opendir.c (revision da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *           Copyright (c) 1985-2007 AT&T Knowledge Ventures            *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                      by AT&T Knowledge Ventures                      *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 /*
24  * opendir, closedir
25  *
26  * open|close directory stream
27  *
28  * POSIX compatible directory stream access routines:
29  *
30  *	#include <sys/types.h>
31  *	#include <dirent.h>
32  *
33  * NOTE: readdir() returns a pointer to struct dirent
34  */
35 
36 #include "dirlib.h"
37 
38 #if _dir_ok
39 
40 NoN(opendir)
41 
42 #else
43 
44 static const char id_dir[] = "\n@(#)$Id: directory (AT&T Research) 1993-04-01 $\0\n";
45 
46 static DIR*	freedirp;		/* always keep one dirp */
47 
48 DIR*
49 opendir(register const char* path)
50 {
51 	register DIR*	dirp = 0;
52 	register int	fd;
53 	struct stat	st;
54 
55 	if ((fd = open(path, O_RDONLY)) < 0) return(0);
56 	if (fstat(fd, &st) < 0 ||
57 	   !S_ISDIR(st.st_mode) && (errno = ENOTDIR) ||
58 	   fcntl(fd, F_SETFD, FD_CLOEXEC) ||
59 	   !(dirp = freedirp ? freedirp :
60 #if defined(_DIR_PRIVATE_) || _ptr_dd_buf
61 	   newof(0, DIR, 1, DIRBLKSIZ)
62 #else
63 	   newof(0, DIR, 1, 0)
64 #endif
65 		))
66 	{
67 		close(fd);
68 		if (dirp)
69 		{
70 			if (!freedirp) freedirp = dirp;
71 			else free(dirp);
72 		}
73 		return(0);
74 	}
75 	freedirp = 0;
76 	dirp->dd_fd = fd;
77 	dirp->dd_loc = dirp->dd_size = 0;	/* refill needed */
78 #if defined(_DIR_PRIVATE_) || _ptr_dd_buf
79 	dirp->dd_buf = (void*)((char*)dirp + sizeof(DIR));
80 #endif
81 	return(dirp);
82 }
83 
84 void
85 closedir(register DIR* dirp)
86 {
87 	if (dirp)
88 	{
89 		close(dirp->dd_fd);
90 		if (!freedirp) freedirp = dirp;
91 		else free(dirp);
92 	}
93 }
94 
95 #endif
96