freebsd-dev/lib/libc/gen/telldir.c
Daniel Eischen d201fe46e3 Remove _THREAD_SAFE and make libc thread-safe by default by
adding (weak definitions to) stubs for some of the pthread
functions.  If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
	__sys_foo - actual system call
	_foo - weak definition to __sys_foo
	foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo.  In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde).  All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes.  <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h  namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE.  We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by:	-arch
2001-01-24 13:01:12 +00:00

134 lines
3.9 KiB
C

/*
* Copyright (c) 1983, 1993
* The 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.
*
* $FreeBSD$
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/param.h>
#include <sys/queue.h>
#include <dirent.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include "un-namespace.h"
#include "libc_private.h"
#include "telldir.h"
/*
* The option SINGLEUSE may be defined to say that a telldir
* cookie may be used only once before it is freed. This option
* is used to avoid having memory usage grow without bound.
*/
#define SINGLEUSE
/*
* return a pointer into a directory
*/
long
telldir(dirp)
DIR *dirp;
{
struct ddloc *lp;
if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL)
return (-1);
if (__isthreaded)
_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
lp->loc_index = dirp->dd_td->td_loccnt++;
lp->loc_seek = dirp->dd_seek;
lp->loc_loc = dirp->dd_loc;
LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe);
if (__isthreaded)
_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
return (lp->loc_index);
}
/*
* seek to an entry in a directory.
* Only values returned by "telldir" should be passed to seekdir.
*/
void
_seekdir(dirp, loc)
DIR *dirp;
long loc;
{
struct ddloc *lp;
struct dirent *dp;
LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) {
if (lp->loc_index == loc)
break;
}
if (lp == NULL)
return;
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
goto found;
(void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
dirp->dd_seek = lp->loc_seek;
dirp->dd_loc = 0;
while (dirp->dd_loc < lp->loc_loc) {
dp = _readdir_unlocked(dirp);
if (dp == NULL)
break;
}
found:
#ifdef SINGLEUSE
LIST_REMOVE(lp, loc_lqe);
free((caddr_t)lp);
#endif
}
/*
* Reclaim memory for telldir cookies which weren't used.
*/
void
_reclaim_telldir(dirp)
DIR *dirp;
{
struct ddloc *lp;
struct ddloc *templp;
lp = LIST_FIRST(&dirp->dd_td->td_locq);
while (lp != NULL) {
templp = lp;
lp = LIST_NEXT(lp, loc_lqe);
free(templp);
}
LIST_INIT(&dirp->dd_td->td_locq);
}