blob: 0e8a7f355f7a1916218a9bd4d874e3ed771c6fc1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/readdir.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 */
6
Kevin Winchester85c9fe82010-08-09 17:20:22 -07007#include <linux/stddef.h>
Milind Arun Choudhary022a1692007-05-08 00:29:02 -07008#include <linux/kernel.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -05009#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/time.h>
11#include <linux/mm.h>
12#include <linux/errno.h>
13#include <linux/stat.h>
14#include <linux/file.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/fs.h>
Heinrich Schuchardtd4c7cf62014-06-04 16:05:41 -070016#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/dirent.h>
18#include <linux/security.h>
19#include <linux/syscalls.h>
20#include <linux/unistd.h>
21
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080022#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Al Viro5c0ba4e2013-05-15 13:52:59 -040024int iterate_dir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -070025{
Al Viro496ad9a2013-01-23 17:07:38 -050026 struct inode *inode = file_inode(file);
Al Viro61922692016-04-20 23:08:32 -040027 bool shared = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 int res = -ENOTDIR;
Al Viro61922692016-04-20 23:08:32 -040029 if (file->f_op->iterate_shared)
30 shared = true;
31 else if (!file->f_op->iterate)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 goto out;
33
34 res = security_file_permission(file, MAY_READ);
35 if (res)
36 goto out;
37
Al Viro00235412016-05-26 00:05:12 -040038 if (shared) {
Al Viro61922692016-04-20 23:08:32 -040039 inode_lock_shared(inode);
Al Viro00235412016-05-26 00:05:12 -040040 } else {
41 res = down_write_killable(&inode->i_rwsem);
42 if (res)
43 goto out;
44 }
Liam R. Howlettda784512007-12-06 17:39:54 -050045
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 res = -ENOENT;
47 if (!IS_DEADDIR(inode)) {
Al Viro2233f312013-05-22 21:44:23 -040048 ctx->pos = file->f_pos;
Al Viro61922692016-04-20 23:08:32 -040049 if (shared)
50 res = file->f_op->iterate_shared(file, ctx);
51 else
52 res = file->f_op->iterate(file, ctx);
Al Viro2233f312013-05-22 21:44:23 -040053 file->f_pos = ctx->pos;
Heinrich Schuchardtd4c7cf62014-06-04 16:05:41 -070054 fsnotify_access(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 file_accessed(file);
56 }
Al Viro61922692016-04-20 23:08:32 -040057 if (shared)
58 inode_unlock_shared(inode);
59 else
60 inode_unlock(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061out:
62 return res;
63}
Al Viro5c0ba4e2013-05-15 13:52:59 -040064EXPORT_SYMBOL(iterate_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66/*
67 * Traditional linux readdir() handling..
68 *
69 * "count=1" is a special case, meaning that the buffer is one
70 * dirent-structure in size and that the code can't handle more
71 * anyway. Thus the special "fillonedir()" function for that
72 * case (the low-level handlers don't need to care about this).
73 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75#ifdef __ARCH_WANT_OLD_READDIR
76
77struct old_linux_dirent {
78 unsigned long d_ino;
79 unsigned long d_offset;
80 unsigned short d_namlen;
81 char d_name[1];
82};
83
84struct readdir_callback {
Al Viro5c0ba4e2013-05-15 13:52:59 -040085 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 struct old_linux_dirent __user * dirent;
87 int result;
88};
89
Miklos Szerediac7576f2014-10-30 17:37:34 +010090static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
91 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
Miklos Szerediac7576f2014-10-30 17:37:34 +010093 struct readdir_callback *buf =
94 container_of(ctx, struct readdir_callback, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 struct old_linux_dirent __user * dirent;
David Howellsafefdbb2006-10-03 01:13:46 -070096 unsigned long d_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98 if (buf->result)
99 return -EINVAL;
David Howellsafefdbb2006-10-03 01:13:46 -0700100 d_ino = ino;
Al Viro8f3f6552008-08-12 00:28:24 -0400101 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
102 buf->result = -EOVERFLOW;
David Howellsafefdbb2006-10-03 01:13:46 -0700103 return -EOVERFLOW;
Al Viro8f3f6552008-08-12 00:28:24 -0400104 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 buf->result++;
106 dirent = buf->dirent;
107 if (!access_ok(VERIFY_WRITE, dirent,
108 (unsigned long)(dirent->d_name + namlen + 1) -
109 (unsigned long)dirent))
110 goto efault;
David Howellsafefdbb2006-10-03 01:13:46 -0700111 if ( __put_user(d_ino, &dirent->d_ino) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 __put_user(offset, &dirent->d_offset) ||
113 __put_user(namlen, &dirent->d_namlen) ||
114 __copy_to_user(dirent->d_name, name, namlen) ||
115 __put_user(0, dirent->d_name + namlen))
116 goto efault;
117 return 0;
118efault:
119 buf->result = -EFAULT;
120 return -EFAULT;
121}
122
Heiko Carstensd4e82042009-01-14 14:14:34 +0100123SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
124 struct old_linux_dirent __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 int error;
Al Viro63b6df12016-04-20 17:08:21 -0400127 struct fd f = fdget_pos(fd);
Al Viroac6614b2013-05-22 22:22:04 -0400128 struct readdir_callback buf = {
129 .ctx.actor = fillonedir,
130 .dirent = dirent
131 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Al Viro2903ff02012-08-28 12:52:22 -0400133 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400134 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
Al Viro5c0ba4e2013-05-15 13:52:59 -0400136 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400137 if (buf.result)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 error = buf.result;
139
Al Viro63b6df12016-04-20 17:08:21 -0400140 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 return error;
142}
143
144#endif /* __ARCH_WANT_OLD_READDIR */
145
146/*
147 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
148 * interface.
149 */
150struct linux_dirent {
151 unsigned long d_ino;
152 unsigned long d_off;
153 unsigned short d_reclen;
154 char d_name[1];
155};
156
157struct getdents_callback {
Al Viro5c0ba4e2013-05-15 13:52:59 -0400158 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 struct linux_dirent __user * current_dir;
160 struct linux_dirent __user * previous;
161 int count;
162 int error;
163};
164
Miklos Szerediac7576f2014-10-30 17:37:34 +0100165static int filldir(struct dir_context *ctx, const char *name, int namlen,
166 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
168 struct linux_dirent __user * dirent;
Miklos Szerediac7576f2014-10-30 17:37:34 +0100169 struct getdents_callback *buf =
170 container_of(ctx, struct getdents_callback, ctx);
David Howellsafefdbb2006-10-03 01:13:46 -0700171 unsigned long d_ino;
Kevin Winchester85c9fe82010-08-09 17:20:22 -0700172 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
173 sizeof(long));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
175 buf->error = -EINVAL; /* only used if we fail.. */
176 if (reclen > buf->count)
177 return -EINVAL;
David Howellsafefdbb2006-10-03 01:13:46 -0700178 d_ino = ino;
Al Viro8f3f6552008-08-12 00:28:24 -0400179 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
180 buf->error = -EOVERFLOW;
David Howellsafefdbb2006-10-03 01:13:46 -0700181 return -EOVERFLOW;
Al Viro8f3f6552008-08-12 00:28:24 -0400182 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 dirent = buf->previous;
184 if (dirent) {
Theodore Ts'o1f60fbe2016-04-23 22:50:07 -0400185 if (signal_pending(current))
186 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 if (__put_user(offset, &dirent->d_off))
188 goto efault;
189 }
190 dirent = buf->current_dir;
David Howellsafefdbb2006-10-03 01:13:46 -0700191 if (__put_user(d_ino, &dirent->d_ino))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 goto efault;
193 if (__put_user(reclen, &dirent->d_reclen))
194 goto efault;
195 if (copy_to_user(dirent->d_name, name, namlen))
196 goto efault;
197 if (__put_user(0, dirent->d_name + namlen))
198 goto efault;
199 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
200 goto efault;
201 buf->previous = dirent;
202 dirent = (void __user *)dirent + reclen;
203 buf->current_dir = dirent;
204 buf->count -= reclen;
205 return 0;
206efault:
207 buf->error = -EFAULT;
208 return -EFAULT;
209}
210
Heiko Carstens20f37032009-01-14 14:14:23 +0100211SYSCALL_DEFINE3(getdents, unsigned int, fd,
212 struct linux_dirent __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
Al Viro2903ff02012-08-28 12:52:22 -0400214 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 struct linux_dirent __user * lastdirent;
Al Viroac6614b2013-05-22 22:22:04 -0400216 struct getdents_callback buf = {
217 .ctx.actor = filldir,
218 .count = count,
219 .current_dir = dirent
220 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 int error;
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 if (!access_ok(VERIFY_WRITE, dirent, count))
Al Viro863ced72012-04-21 18:40:32 -0400224 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Al Viro63b6df12016-04-20 17:08:21 -0400226 f = fdget_pos(fd);
Al Viro2903ff02012-08-28 12:52:22 -0400227 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400228 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
Al Viro5c0ba4e2013-05-15 13:52:59 -0400230 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400231 if (error >= 0)
232 error = buf.error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 lastdirent = buf.previous;
234 if (lastdirent) {
Al Virobb6f6192013-05-15 18:49:12 -0400235 if (put_user(buf.ctx.pos, &lastdirent->d_off))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 error = -EFAULT;
237 else
238 error = count - buf.count;
239 }
Al Viro63b6df12016-04-20 17:08:21 -0400240 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 return error;
242}
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244struct getdents_callback64 {
Al Viro5c0ba4e2013-05-15 13:52:59 -0400245 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 struct linux_dirent64 __user * current_dir;
247 struct linux_dirent64 __user * previous;
248 int count;
249 int error;
250};
251
Miklos Szerediac7576f2014-10-30 17:37:34 +0100252static int filldir64(struct dir_context *ctx, const char *name, int namlen,
253 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254{
255 struct linux_dirent64 __user *dirent;
Miklos Szerediac7576f2014-10-30 17:37:34 +0100256 struct getdents_callback64 *buf =
257 container_of(ctx, struct getdents_callback64, ctx);
Kevin Winchester85c9fe82010-08-09 17:20:22 -0700258 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
259 sizeof(u64));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 buf->error = -EINVAL; /* only used if we fail.. */
262 if (reclen > buf->count)
263 return -EINVAL;
264 dirent = buf->previous;
265 if (dirent) {
Theodore Ts'o1f60fbe2016-04-23 22:50:07 -0400266 if (signal_pending(current))
267 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 if (__put_user(offset, &dirent->d_off))
269 goto efault;
270 }
271 dirent = buf->current_dir;
272 if (__put_user(ino, &dirent->d_ino))
273 goto efault;
274 if (__put_user(0, &dirent->d_off))
275 goto efault;
276 if (__put_user(reclen, &dirent->d_reclen))
277 goto efault;
278 if (__put_user(d_type, &dirent->d_type))
279 goto efault;
280 if (copy_to_user(dirent->d_name, name, namlen))
281 goto efault;
282 if (__put_user(0, dirent->d_name + namlen))
283 goto efault;
284 buf->previous = dirent;
285 dirent = (void __user *)dirent + reclen;
286 buf->current_dir = dirent;
287 buf->count -= reclen;
288 return 0;
289efault:
290 buf->error = -EFAULT;
291 return -EFAULT;
292}
293
Heiko Carstens20f37032009-01-14 14:14:23 +0100294SYSCALL_DEFINE3(getdents64, unsigned int, fd,
295 struct linux_dirent64 __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296{
Al Viro2903ff02012-08-28 12:52:22 -0400297 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 struct linux_dirent64 __user * lastdirent;
Al Viroac6614b2013-05-22 22:22:04 -0400299 struct getdents_callback64 buf = {
300 .ctx.actor = filldir64,
301 .count = count,
302 .current_dir = dirent
303 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 int error;
305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 if (!access_ok(VERIFY_WRITE, dirent, count))
Al Viro863ced72012-04-21 18:40:32 -0400307 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
Al Viro63b6df12016-04-20 17:08:21 -0400309 f = fdget_pos(fd);
Al Viro2903ff02012-08-28 12:52:22 -0400310 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400311 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
Al Viro5c0ba4e2013-05-15 13:52:59 -0400313 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400314 if (error >= 0)
315 error = buf.error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 lastdirent = buf.previous;
317 if (lastdirent) {
Al Virobb6f6192013-05-15 18:49:12 -0400318 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 if (__put_user(d_off, &lastdirent->d_off))
Al Viro53c9c5c2008-08-24 07:29:52 -0400320 error = -EFAULT;
321 else
322 error = count - buf.count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 }
Al Viro63b6df12016-04-20 17:08:21 -0400324 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 return error;
326}