| OLD | NEW |
|---|
| (Empty) |
| 1 /* | |
| 2 Unix SMB/CIFS implementation. | |
| 3 | |
| 4 Copyright (C) Andrew Tridgell 2005 | |
| 5 | |
| 6 ** NOTE! The following LGPL license applies to the replace | |
| 7 ** library. This does NOT imply that all of Samba is released | |
| 8 ** under the LGPL | |
| 9 | |
| 10 This library is free software; you can redistribute it and/or | |
| 11 modify it under the terms of the GNU Lesser General Public | |
| 12 License as published by the Free Software Foundation; either | |
| 13 version 3 of the License, or (at your option) any later version. | |
| 14 | |
| 15 This library is distributed in the hope that it will be useful, | |
| 16 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 18 Lesser General Public License for more details. | |
| 19 | |
| 20 You should have received a copy of the GNU Lesser General Public | |
| 21 License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
| 22 */ | |
| 23 /* | |
| 24 a replacement for opendir/readdir/telldir/seekdir/closedir for BSD systems | |
| 25 | |
| 26 This is needed because the existing directory handling in FreeBSD | |
| 27 and OpenBSD (and possibly NetBSD) doesn't correctly handle unlink() | |
| 28 on files in a directory where telldir() has been used. On a block | |
| 29 boundary it will occasionally miss a file when seekdir() is used to | |
| 30 return to a position previously recorded with telldir(). | |
| 31 | |
| 32 This also fixes a severe performance and memory usage problem with | |
| 33 telldir() on BSD systems. Each call to telldir() in BSD adds an | |
| 34 entry to a linked list, and those entries are cleaned up on | |
| 35 closedir(). This means with a large directory closedir() can take an | |
| 36 arbitrary amount of time, causing network timeouts as millions of | |
| 37 telldir() entries are freed | |
| 38 | |
| 39 Note! This replacement code is not portable. It relies on getdents() | |
| 40 always leaving the file descriptor at a seek offset that is a | |
| 41 multiple of DIR_BUF_SIZE. If the code detects that this doesn't | |
| 42 happen then it will abort(). It also does not handle directories | |
| 43 with offsets larger than can be stored in a long, | |
| 44 | |
| 45 This code is available under other free software licenses as | |
| 46 well. Contact the author. | |
| 47 */ | |
| 48 | |
| 49 #include <stdlib.h> | |
| 50 #include <sys/stat.h> | |
| 51 #include <unistd.h> | |
| 52 #include <sys/types.h> | |
| 53 #include <errno.h> | |
| 54 #include <fcntl.h> | |
| 55 #include <dirent.h> | |
| 56 | |
| 57 #define DIR_BUF_BITS 9 | |
| 58 #define DIR_BUF_SIZE (1<<DIR_BUF_BITS) | |
| 59 | |
| 60 struct dir_buf { | |
| 61 int fd; | |
| 62 int nbytes, ofs; | |
| 63 off_t seekpos; | |
| 64 char buf[DIR_BUF_SIZE]; | |
| 65 }; | |
| 66 | |
| 67 DIR *opendir(const char *dname) | |
| 68 { | |
| 69 struct dir_buf *d; | |
| 70 struct stat sb; | |
| 71 d = malloc(sizeof(*d)); | |
| 72 if (d == NULL) { | |
| 73 errno = ENOMEM; | |
| 74 return NULL; | |
| 75 } | |
| 76 d->fd = open(dname, O_RDONLY); | |
| 77 if (d->fd == -1) { | |
| 78 free(d); | |
| 79 return NULL; | |
| 80 } | |
| 81 if (fstat(d->fd, &sb) < 0) { | |
| 82 close(d->fd); | |
| 83 free(d); | |
| 84 return NULL; | |
| 85 } | |
| 86 if (!S_ISDIR(sb.st_mode)) { | |
| 87 close(d->fd); | |
| 88 free(d); | |
| 89 errno = ENOTDIR; | |
| 90 return NULL; | |
| 91 } | |
| 92 d->ofs = 0; | |
| 93 d->seekpos = 0; | |
| 94 d->nbytes = 0; | |
| 95 return (DIR *)d; | |
| 96 } | |
| 97 | |
| 98 struct dirent *readdir(DIR *dir) | |
| 99 { | |
| 100 struct dir_buf *d = (struct dir_buf *)dir; | |
| 101 struct dirent *de; | |
| 102 | |
| 103 if (d->ofs >= d->nbytes) { | |
| 104 d->seekpos = lseek(d->fd, 0, SEEK_CUR); | |
| 105 d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE); | |
| 106 d->ofs = 0; | |
| 107 } | |
| 108 if (d->ofs >= d->nbytes) { | |
| 109 return NULL; | |
| 110 } | |
| 111 de = (struct dirent *)&d->buf[d->ofs]; | |
| 112 d->ofs += de->d_reclen; | |
| 113 return de; | |
| 114 } | |
| 115 | |
| 116 long telldir(DIR *dir) | |
| 117 { | |
| 118 struct dir_buf *d = (struct dir_buf *)dir; | |
| 119 if (d->ofs >= d->nbytes) { | |
| 120 d->seekpos = lseek(d->fd, 0, SEEK_CUR); | |
| 121 d->ofs = 0; | |
| 122 d->nbytes = 0; | |
| 123 } | |
| 124 /* this relies on seekpos always being a multiple of | |
| 125 DIR_BUF_SIZE. Is that always true on BSD systems? */ | |
| 126 if (d->seekpos & (DIR_BUF_SIZE-1)) { | |
| 127 abort(); | |
| 128 } | |
| 129 return d->seekpos + d->ofs; | |
| 130 } | |
| 131 | |
| 132 void seekdir(DIR *dir, long ofs) | |
| 133 { | |
| 134 struct dir_buf *d = (struct dir_buf *)dir; | |
| 135 d->seekpos = lseek(d->fd, ofs & ~(DIR_BUF_SIZE-1), SEEK_SET); | |
| 136 d->nbytes = getdents(d->fd, d->buf, DIR_BUF_SIZE); | |
| 137 d->ofs = 0; | |
| 138 while (d->ofs < (ofs & (DIR_BUF_SIZE-1))) { | |
| 139 if (readdir(dir) == NULL) break; | |
| 140 } | |
| 141 } | |
| 142 | |
| 143 void rewinddir(DIR *dir) | |
| 144 { | |
| 145 seekdir(dir, 0); | |
| 146 } | |
| 147 | |
| 148 int closedir(DIR *dir) | |
| 149 { | |
| 150 struct dir_buf *d = (struct dir_buf *)dir; | |
| 151 int r = close(d->fd); | |
| 152 if (r != 0) { | |
| 153 return r; | |
| 154 } | |
| 155 free(d); | |
| 156 return 0; | |
| 157 } | |
| 158 | |
| 159 #ifndef dirfd | |
| 160 /* darn, this is a macro on some systems. */ | |
| 161 int dirfd(DIR *dir) | |
| 162 { | |
| 163 struct dir_buf *d = (struct dir_buf *)dir; | |
| 164 return d->fd; | |
| 165 } | |
| 166 #endif | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 2282793002:
Remove unused third_party/talloc (Closed)
