NetBSD/lib/libc/gen/directory.c

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/*
* 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 = "from: @(#)closedir.c 5.9 (Berkeley) 2/23/91";*/
1994-03-28 06:34:45 +04:00
static char *rcsid = "$Id: directory.c,v 1.4 1994/03/28 02:34:45 cgd Exp $";
#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;
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);
}