1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. 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[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93"; 36 #endif /* LIBC_SCCS and not lint */ 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "namespace.h" 41 #include <sys/param.h> 42 #include <sys/queue.h> 43 #include <dirent.h> 44 #include <pthread.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 #include "un-namespace.h" 48 49 #include "libc_private.h" 50 #include "telldir.h" 51 52 /* 53 * The option SINGLEUSE may be defined to say that a telldir 54 * cookie may be used only once before it is freed. This option 55 * is used to avoid having memory usage grow without bound. 56 */ 57 #define SINGLEUSE 58 59 /* 60 * return a pointer into a directory 61 */ 62 long 63 telldir(dirp) 64 DIR *dirp; 65 { 66 struct ddloc *lp; 67 68 if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL) 69 return (-1); 70 if (__isthreaded) 71 _pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock); 72 lp->loc_index = dirp->dd_td->td_loccnt++; 73 lp->loc_seek = dirp->dd_seek; 74 lp->loc_loc = dirp->dd_loc; 75 LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe); 76 if (__isthreaded) 77 _pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock); 78 return (lp->loc_index); 79 } 80 81 /* 82 * seek to an entry in a directory. 83 * Only values returned by "telldir" should be passed to seekdir. 84 */ 85 void 86 _seekdir(dirp, loc) 87 DIR *dirp; 88 long loc; 89 { 90 struct ddloc *lp; 91 struct dirent *dp; 92 93 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) { 94 if (lp->loc_index == loc) 95 break; 96 } 97 if (lp == NULL) 98 return; 99 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek) 100 goto found; 101 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET); 102 dirp->dd_seek = lp->loc_seek; 103 dirp->dd_loc = 0; 104 while (dirp->dd_loc < lp->loc_loc) { 105 dp = _readdir_unlocked(dirp); 106 if (dp == NULL) 107 break; 108 } 109 found: 110 #ifdef SINGLEUSE 111 LIST_REMOVE(lp, loc_lqe); 112 free((caddr_t)lp); 113 #endif 114 } 115 116 /* 117 * Reclaim memory for telldir cookies which weren't used. 118 */ 119 void 120 _reclaim_telldir(dirp) 121 DIR *dirp; 122 { 123 struct ddloc *lp; 124 struct ddloc *templp; 125 126 lp = LIST_FIRST(&dirp->dd_td->td_locq); 127 while (lp != NULL) { 128 templp = lp; 129 lp = LIST_NEXT(lp, loc_lqe); 130 free(templp); 131 } 132 LIST_INIT(&dirp->dd_td->td_locq); 133 } 134