[unix-history] / lib / libc / gen / directory.c

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)closedir.c	5.9 (Berkeley) 2/23/91";
#endif /* LIBC_SCCS and not lint */

/*
 * One of these structures is malloced to describe the current directory
 * position each time telldir is called. It records the current magic 
 * cookie returned by getdirentries and the offset within the buffer
 * associated with that return value.
 */
struct ddloc {
	struct	ddloc *loc_next;/* next structure in list */
	long	loc_index;	/* key associated with structure */
	long	loc_seek;	/* magic cookie returned by getdirentries */
	long	loc_loc;	/* offset of entry in buffer */
};

static long	dd_loccnt = 0;	/* Index of entry for sequential telldir's */

#include <sys/types.h>
#include <sys/param.h>
#include <dirent.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

/*
 * close a directory.
 */
int
closedir(dirp)
	register DIR *dirp;
{
	struct ddloc *ptr, *nextptr;
	int fd;

	fd = dirp->dd_fd;
	dirp->dd_fd = -1;
	dirp->dd_loc = 0;
	for (ptr = (struct ddloc*)dirp->dd_ddloc; ptr; ptr = nextptr) {
		nextptr = ptr->loc_next;
		free((void *)ptr);
	}
	free((void *)dirp->dd_buf);
	free((void *)dirp);
	return(close(fd));
}

/*
 * open a directory.
 */
DIR *
opendir(name)
	const char *name;
{
	register DIR *dirp;
	register int fd;

	if ((fd = open(name, 0)) == -1)
		return NULL;
	if (fcntl(fd, F_SETFD, 1) == -1 ||
	    (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
		close (fd);
		return NULL;
	}
	/*
	 * If CLSIZE is an exact multiple of DIRBLKSIZ, use a CLSIZE
	 * buffer that it cluster boundary aligned.
	 * Hopefully this can be a big win someday by allowing page trades
	 * to user space to be done by getdirentries()
	 */
	if ((CLSIZE % DIRBLKSIZ) == 0) {
		dirp->dd_buf = malloc(CLSIZE);
		dirp->dd_len = CLSIZE;
	} else {
		dirp->dd_buf = malloc(DIRBLKSIZ);
		dirp->dd_len = DIRBLKSIZ;
	}
	if (dirp->dd_buf == NULL) {
		close (fd);
		free(dirp);
		return NULL;
	}
	dirp->dd_fd = fd;
	dirp->dd_loc = 0;
	dirp->dd_seek = 0;
	dirp->dd_ddloc = NULL;

	return dirp;
}

/*
 * get next entry in a directory.
 */
struct dirent *
readdir(dirp)
	register DIR *dirp;
{
	register struct dirent *dp;

	for (;;) {
		if (dirp->dd_loc == 0) {
			dirp->dd_size = getdirentries(dirp->dd_fd,
			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
			if (dirp->dd_size <= 0)
				return NULL;
		}
		if (dirp->dd_loc >= dirp->dd_size) {
			dirp->dd_loc = 0;
			continue;
		}
		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
		if ((int)dp & 03)	/* bogus pointer check */
			return NULL;
		if (dp->d_reclen <= 0 ||
		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
			return NULL;
		dirp->dd_loc += dp->d_reclen;
		if (dp->d_ino == 0)
			continue;
		return (dp);
	}
}

void
rewinddir(dirp)
	DIR *dirp;
{
	(void)lseek(dirp->dd_fd, 0, 0);
	dirp->dd_seek = 0;
	dirp->dd_loc = 0;
}

/*
 * Seek to an entry in a directory.
 * _seekdir is in telldir.c so that it can share opaque data structures.
 */
void
seekdir(dirp, loc)
	DIR *dirp;
	long loc;
{
	register struct ddloc **prevlp;
	register struct ddloc *lp;
	struct dirent *dp;
	extern long lseek();

	prevlp = (struct ddloc **)&(dirp->dd_ddloc);
	lp = *prevlp;
	while (lp != NULL) {
		if (lp->loc_index == loc)
			break;
		prevlp = &lp->loc_next;
		lp = lp->loc_next;
	}
	if (lp) {
		if (lp->loc_seek != dirp->dd_seek) {
			if (lseek(dirp->dd_fd, lp->loc_seek, 0) == -1) {
				*prevlp = lp->loc_next;
				free(lp);
				return;
			}
			dirp->dd_seek = lp->loc_seek;
			dirp->dd_loc = 0;
			while (dirp->dd_loc < lp->loc_loc) {
				if (!(dp = readdir(dirp))) {
					*prevlp = lp->loc_next;
					free(lp);
					return;
				}
			}
		}
	}
}

/*
 * return a pointer into a directory
 */
long
telldir(dirp)
	const DIR *dirp;
{
	register struct ddloc *lp, **fakeout;

	if (lp = (struct ddloc *)malloc(sizeof(struct ddloc))) {
		lp->loc_index = dd_loccnt++;
		lp->loc_seek = dirp->dd_seek;
		lp->loc_loc = dirp->dd_loc;
		lp->loc_next = dirp->dd_ddloc;

		/* Compiler won't let us change anything pointed to by db directly */
		/* So we fake to the left and do it anyway */
		/* Wonder if the compile optomizes it to the correct solution */
		fakeout = (struct ddloc **)&(dirp->dd_ddloc);
		*fakeout = lp;

		return (lp->loc_index);
	}
	return (-1);
}
Commit	Line	Data
9b07ac93 NW	1	/*
	2	* Copyright (c) 1983 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 3. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
	32	*/
	33
	34	#if defined(LIBC_SCCS) && !defined(lint)
	35	static char sccsid[] = "@(#)closedir.c 5.9 (Berkeley) 2/23/91";
	36	#endif /* LIBC_SCCS and not lint */
	37
	38	/*
	39	* One of these structures is malloced to describe the current directory
	40	* position each time telldir is called. It records the current magic
	41	* cookie returned by getdirentries and the offset within the buffer
	42	* associated with that return value.
	43	*/
	44	struct ddloc {
	45	struct ddloc loc_next;/ next structure in list */
	46	long loc_index; /* key associated with structure */
	47	long loc_seek; /* magic cookie returned by getdirentries */
	48	long loc_loc; /* offset of entry in buffer */
	49	};
	50
	51	static long dd_loccnt = 0; /* Index of entry for sequential telldir's */
	52
	53	#include <sys/types.h>
	54	#include <sys/param.h>
	55	#include <dirent.h>
	56	#include <stdlib.h>
	57	#include <unistd.h>
	58	#include <fcntl.h>
	59
	60	/*
	61	* close a directory.
	62	*/
	63	int
	64	closedir(dirp)
65	register DIR *dirp;
66	{
67	struct ddloc ptr, nextptr;
68	int fd;
69
70	fd = dirp->dd_fd;
71	dirp->dd_fd = -1;
72	dirp->dd_loc = 0;
73	for (ptr = (struct ddloc*)dirp->dd_ddloc; ptr; ptr = nextptr) {
74	nextptr = ptr->loc_next;
75	free((void *)ptr);
76	}
77	free((void *)dirp->dd_buf);
78	free((void *)dirp);
79	return(close(fd));
80	}
81
82	/*
83	* open a directory.
84	*/
85	DIR *
86	opendir(name)
87	const char *name;
88	{
89	register DIR *dirp;
90	register int fd;
91
92	if ((fd = open(name, 0)) == -1)
93	return NULL;
94	if (fcntl(fd, F_SETFD, 1) == -1 \|\|
95	(dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
96	close (fd);
97	return NULL;
98	}
99	/*
100	* If CLSIZE is an exact multiple of DIRBLKSIZ, use a CLSIZE
101	* buffer that it cluster boundary aligned.
102	* Hopefully this can be a big win someday by allowing page trades
103	* to user space to be done by getdirentries()
104	*/
105	if ((CLSIZE % DIRBLKSIZ) == 0) {
106	dirp->dd_buf = malloc(CLSIZE);
107	dirp->dd_len = CLSIZE;
108	} else {
109	dirp->dd_buf = malloc(DIRBLKSIZ);
110	dirp->dd_len = DIRBLKSIZ;
111	}
112	if (dirp->dd_buf == NULL) {
113	close (fd);
114	free(dirp);
115	return NULL;
116	}
117	dirp->dd_fd = fd;
118	dirp->dd_loc = 0;
119	dirp->dd_seek = 0;
120	dirp->dd_ddloc = NULL;
121
122	return dirp;
123	}
124
125	/*
126	* get next entry in a directory.
127	*/
128	struct dirent *
129	readdir(dirp)
130	register DIR *dirp;
131	{
132	register struct dirent *dp;
133
134	for (;;) {
135	if (dirp->dd_loc == 0) {
136	dirp->dd_size = getdirentries(dirp->dd_fd,
137	dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
138	if (dirp->dd_size <= 0)
139	return NULL;
140	}
141	if (dirp->dd_loc >= dirp->dd_size) {
142	dirp->dd_loc = 0;
143	continue;
144	}
145	dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
146	if ((int)dp & 03) /* bogus pointer check */
147	return NULL;
148	if (dp->d_reclen <= 0 \|\|
149	dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
150	return NULL;
151	dirp->dd_loc += dp->d_reclen;
152	if (dp->d_ino == 0)
153	continue;
154	return (dp);
155	}
156	}
157
158	void
159	rewinddir(dirp)
160	DIR *dirp;
161	{
162	(void)lseek(dirp->dd_fd, 0, 0);
163	dirp->dd_seek = 0;
164	dirp->dd_loc = 0;
165	}
166
167	/*
168	* Seek to an entry in a directory.
169	* _seekdir is in telldir.c so that it can share opaque data structures.
170	*/
171	void
172	seekdir(dirp, loc)
173	DIR *dirp;
174	long loc;
175	{
176	register struct ddloc **prevlp;
177	register struct ddloc *lp;
178	struct dirent *dp;
179	extern long lseek();
180
181	prevlp = (struct ddloc **)&(dirp->dd_ddloc);
182	lp = *prevlp;
183	while (lp != NULL) {
184	if (lp->loc_index == loc)
185	break;
186	prevlp = &lp->loc_next;
187	lp = lp->loc_next;
188	}
189	if (lp) {
190	if (lp->loc_seek != dirp->dd_seek) {
191	if (lseek(dirp->dd_fd, lp->loc_seek, 0) == -1) {
192	*prevlp = lp->loc_next;
193	free(lp);
194	return;
195	}
196	dirp->dd_seek = lp->loc_seek;
197	dirp->dd_loc = 0;
198	while (dirp->dd_loc < lp->loc_loc) {
199	if (!(dp = readdir(dirp))) {
200	*prevlp = lp->loc_next;
201	free(lp);
202	return;
203	}
204	}
205	}
206	}
207	}
208
209	/*
210	* return a pointer into a directory
211	*/
212	long
213	telldir(dirp)
214	const DIR *dirp;
215	{
216	register struct ddloc lp, *fakeout;
217
218	if (lp = (struct ddloc *)malloc(sizeof(struct ddloc))) {
219	lp->loc_index = dd_loccnt++;
220	lp->loc_seek = dirp->dd_seek;
221	lp->loc_loc = dirp->dd_loc;
222	lp->loc_next = dirp->dd_ddloc;
223
224	/* Compiler won't let us change anything pointed to by db directly */
225	/* So we fake to the left and do it anyway */
226	/* Wonder if the compile optomizes it to the correct solution */
227	fakeout = (struct ddloc **)&(dirp->dd_ddloc);
228	*fakeout = lp;
229
230	return (lp->loc_index);
231	}
232	return (-1);
233	}
234