diff options
Diffstat (limited to 'lib/libc/gen/telldir.c')
| -rw-r--r-- | lib/libc/gen/telldir.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/lib/libc/gen/telldir.c b/lib/libc/gen/telldir.c new file mode 100644 index 0000000..77ebcbb --- /dev/null +++ b/lib/libc/gen/telldir.c @@ -0,0 +1,129 @@ +/* + * 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. + * 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[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#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); +} |
