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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/queue.h> 39 #include <dirent.h> 40 #include <pthread.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include "un-namespace.h" 44 45 #include "libc_private.h" 46 #include "gen-private.h" 47 #include "telldir.h" 48 49 /* 50 * The option SINGLEUSE may be defined to say that a telldir 51 * cookie may be used only once before it is freed. This option 52 * is used to avoid having memory usage grow without bound. 53 */ 54 #define SINGLEUSE 55 56 /* 57 * return a pointer into a directory 58 */ 59 long 60 telldir(dirp) 61 DIR *dirp; 62 { 63 struct ddloc *lp; 64 65 if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL) 66 return (-1); 67 if (__isthreaded) 68 _pthread_mutex_lock(&dirp->dd_lock); 69 lp->loc_index = dirp->dd_td->td_loccnt++; 70 lp->loc_seek = dirp->dd_seek; 71 lp->loc_loc = dirp->dd_loc; 72 LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe); 73 if (__isthreaded) 74 _pthread_mutex_unlock(&dirp->dd_lock); 75 return (lp->loc_index); 76 } 77 78 /* 79 * seek to an entry in a directory. 80 * Only values returned by "telldir" should be passed to seekdir. 81 */ 82 void 83 _seekdir(dirp, loc) 84 DIR *dirp; 85 long loc; 86 { 87 struct ddloc *lp; 88 struct dirent *dp; 89 90 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) { 91 if (lp->loc_index == loc) 92 break; 93 } 94 if (lp == NULL) 95 return; 96 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek) 97 goto found; 98 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET); 99 dirp->dd_seek = lp->loc_seek; 100 dirp->dd_loc = 0; 101 while (dirp->dd_loc < lp->loc_loc) { 102 dp = _readdir_unlocked(dirp, 0); 103 if (dp == NULL) 104 break; 105 } 106 found: 107 #ifdef SINGLEUSE 108 LIST_REMOVE(lp, loc_lqe); 109 free((caddr_t)lp); 110 #endif 111 } 112 113 /* 114 * Reclaim memory for telldir cookies which weren't used. 115 */ 116 void 117 _reclaim_telldir(dirp) 118 DIR *dirp; 119 { 120 struct ddloc *lp; 121 struct ddloc *templp; 122 123 lp = LIST_FIRST(&dirp->dd_td->td_locq); 124 while (lp != NULL) { 125 templp = lp; 126 lp = LIST_NEXT(lp, loc_lqe); 127 free(templp); 128 } 129 LIST_INIT(&dirp->dd_td->td_locq); 130 } 131