File: rdu.c

package info (click to toggle)
aufs 4.19+20190211-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 1,316 kB
  • sloc: ansic: 27,214; makefile: 100
file content (382 lines) | stat: -rw-r--r-- 8,646 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2005-2019 Junjiro R. Okajima
 *
 * This program, aufs is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * readdir in userspace.
 */

#include <linux/compat.h>
#include <linux/fs_stack.h>
#include <linux/security.h>
#include "aufs.h"

/* bits for struct aufs_rdu.flags */
#define	AuRdu_CALLED	1
#define	AuRdu_CONT	(1 << 1)
#define	AuRdu_FULL	(1 << 2)
#define au_ftest_rdu(flags, name)	((flags) & AuRdu_##name)
#define au_fset_rdu(flags, name) \
	do { (flags) |= AuRdu_##name; } while (0)
#define au_fclr_rdu(flags, name) \
	do { (flags) &= ~AuRdu_##name; } while (0)

struct au_rdu_arg {
	struct dir_context		ctx;
	struct aufs_rdu			*rdu;
	union au_rdu_ent_ul		ent;
	unsigned long			end;

	struct super_block		*sb;
	int				err;
};

static int au_rdu_fill(struct dir_context *ctx, const char *name, int nlen,
		       loff_t offset, u64 h_ino, unsigned int d_type)
{
	int err, len;
	struct au_rdu_arg *arg = container_of(ctx, struct au_rdu_arg, ctx);
	struct aufs_rdu *rdu = arg->rdu;
	struct au_rdu_ent ent;

	err = 0;
	arg->err = 0;
	au_fset_rdu(rdu->cookie.flags, CALLED);
	len = au_rdu_len(nlen);
	if (arg->ent.ul + len  < arg->end) {
		ent.ino = h_ino;
		ent.bindex = rdu->cookie.bindex;
		ent.type = d_type;
		ent.nlen = nlen;
		if (unlikely(nlen > AUFS_MAX_NAMELEN))
			ent.type = DT_UNKNOWN;

		/* unnecessary to support mmap_sem since this is a dir */
		err = -EFAULT;
		if (copy_to_user(arg->ent.e, &ent, sizeof(ent)))
			goto out;
		if (copy_to_user(arg->ent.e->name, name, nlen))
			goto out;
		/* the terminating NULL */
		if (__put_user(0, arg->ent.e->name + nlen))
			goto out;
		err = 0;
		/* AuDbg("%p, %.*s\n", arg->ent.p, nlen, name); */
		arg->ent.ul += len;
		rdu->rent++;
	} else {
		err = -EFAULT;
		au_fset_rdu(rdu->cookie.flags, FULL);
		rdu->full = 1;
		rdu->tail = arg->ent;
	}

out:
	/* AuTraceErr(err); */
	return err;
}

static int au_rdu_do(struct file *h_file, struct au_rdu_arg *arg)
{
	int err;
	loff_t offset;
	struct au_rdu_cookie *cookie = &arg->rdu->cookie;

	/* we don't have to care (FMODE_32BITHASH | FMODE_64BITHASH) for ext4 */
	offset = vfsub_llseek(h_file, cookie->h_pos, SEEK_SET);
	err = offset;
	if (unlikely(offset != cookie->h_pos))
		goto out;

	err = 0;
	do {
		arg->err = 0;
		au_fclr_rdu(cookie->flags, CALLED);
		/* smp_mb(); */
		err = vfsub_iterate_dir(h_file, &arg->ctx);
		if (err >= 0)
			err = arg->err;
	} while (!err
		 && au_ftest_rdu(cookie->flags, CALLED)
		 && !au_ftest_rdu(cookie->flags, FULL));
	cookie->h_pos = h_file->f_pos;

out:
	AuTraceErr(err);
	return err;
}

static int au_rdu(struct file *file, struct aufs_rdu *rdu)
{
	int err;
	aufs_bindex_t bbot;
	struct au_rdu_arg arg = {
		.ctx = {
			.actor = au_rdu_fill
		}
	};
	struct dentry *dentry;
	struct inode *inode;
	struct file *h_file;
	struct au_rdu_cookie *cookie = &rdu->cookie;

	err = !access_ok(VERIFY_WRITE, rdu->ent.e, rdu->sz);
	if (unlikely(err)) {
		err = -EFAULT;
		AuTraceErr(err);
		goto out;
	}
	rdu->rent = 0;
	rdu->tail = rdu->ent;
	rdu->full = 0;
	arg.rdu = rdu;
	arg.ent = rdu->ent;
	arg.end = arg.ent.ul;
	arg.end += rdu->sz;

	err = -ENOTDIR;
	if (unlikely(!file->f_op->iterate && !file->f_op->iterate_shared))
		goto out;

	err = security_file_permission(file, MAY_READ);
	AuTraceErr(err);
	if (unlikely(err))
		goto out;

	dentry = file->f_path.dentry;
	inode = d_inode(dentry);
	inode_lock_shared(inode);

	arg.sb = inode->i_sb;
	err = si_read_lock(arg.sb, AuLock_FLUSH | AuLock_NOPLM);
	if (unlikely(err))
		goto out_mtx;
	err = au_alive_dir(dentry);
	if (unlikely(err))
		goto out_si;
	/* todo: reval? */
	fi_read_lock(file);

	err = -EAGAIN;
	if (unlikely(au_ftest_rdu(cookie->flags, CONT)
		     && cookie->generation != au_figen(file)))
		goto out_unlock;

	err = 0;
	if (!rdu->blk) {
		rdu->blk = au_sbi(arg.sb)->si_rdblk;
		if (!rdu->blk)
			rdu->blk = au_dir_size(file, /*dentry*/NULL);
	}
	bbot = au_fbtop(file);
	if (cookie->bindex < bbot)
		cookie->bindex = bbot;
	bbot = au_fbbot_dir(file);
	/* AuDbg("b%d, b%d\n", cookie->bindex, bbot); */
	for (; !err && cookie->bindex <= bbot;
	     cookie->bindex++, cookie->h_pos = 0) {
		h_file = au_hf_dir(file, cookie->bindex);
		if (!h_file)
			continue;

		au_fclr_rdu(cookie->flags, FULL);
		err = au_rdu_do(h_file, &arg);
		AuTraceErr(err);
		if (unlikely(au_ftest_rdu(cookie->flags, FULL) || err))
			break;
	}
	AuDbg("rent %llu\n", rdu->rent);

	if (!err && !au_ftest_rdu(cookie->flags, CONT)) {
		rdu->shwh = !!au_opt_test(au_sbi(arg.sb)->si_mntflags, SHWH);
		au_fset_rdu(cookie->flags, CONT);
		cookie->generation = au_figen(file);
	}

	ii_read_lock_child(inode);
	fsstack_copy_attr_atime(inode, au_h_iptr(inode, au_ibtop(inode)));
	ii_read_unlock(inode);

out_unlock:
	fi_read_unlock(file);
out_si:
	si_read_unlock(arg.sb);
out_mtx:
	inode_unlock_shared(inode);
out:
	AuTraceErr(err);
	return err;
}

static int au_rdu_ino(struct file *file, struct aufs_rdu *rdu)
{
	int err;
	ino_t ino;
	unsigned long long nent;
	union au_rdu_ent_ul *u;
	struct au_rdu_ent ent;
	struct super_block *sb;

	err = 0;
	nent = rdu->nent;
	u = &rdu->ent;
	sb = file->f_path.dentry->d_sb;
	si_read_lock(sb, AuLock_FLUSH);
	while (nent-- > 0) {
		/* unnecessary to support mmap_sem since this is a dir */
		err = copy_from_user(&ent, u->e, sizeof(ent));
		if (!err)
			err = !access_ok(VERIFY_WRITE, &u->e->ino, sizeof(ino));
		if (unlikely(err)) {
			err = -EFAULT;
			AuTraceErr(err);
			break;
		}

		/* AuDbg("b%d, i%llu\n", ent.bindex, ent.ino); */
		if (!ent.wh)
			err = au_ino(sb, ent.bindex, ent.ino, ent.type, &ino);
		else
			err = au_wh_ino(sb, ent.bindex, ent.ino, ent.type,
					&ino);
		if (unlikely(err)) {
			AuTraceErr(err);
			break;
		}

		err = __put_user(ino, &u->e->ino);
		if (unlikely(err)) {
			err = -EFAULT;
			AuTraceErr(err);
			break;
		}
		u->ul += au_rdu_len(ent.nlen);
	}
	si_read_unlock(sb);

	return err;
}

/* ---------------------------------------------------------------------- */

static int au_rdu_verify(struct aufs_rdu *rdu)
{
	AuDbg("rdu{%llu, %p, %u | %u | %llu, %u, %u | "
	      "%llu, b%d, 0x%x, g%u}\n",
	      rdu->sz, rdu->ent.e, rdu->verify[AufsCtlRduV_SZ],
	      rdu->blk,
	      rdu->rent, rdu->shwh, rdu->full,
	      rdu->cookie.h_pos, rdu->cookie.bindex, rdu->cookie.flags,
	      rdu->cookie.generation);

	if (rdu->verify[AufsCtlRduV_SZ] == sizeof(*rdu))
		return 0;

	AuDbg("%u:%u\n",
	      rdu->verify[AufsCtlRduV_SZ], (unsigned int)sizeof(*rdu));
	return -EINVAL;
}

long au_rdu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	long err, e;
	struct aufs_rdu rdu;
	void __user *p = (void __user *)arg;

	err = copy_from_user(&rdu, p, sizeof(rdu));
	if (unlikely(err)) {
		err = -EFAULT;
		AuTraceErr(err);
		goto out;
	}
	err = au_rdu_verify(&rdu);
	if (unlikely(err))
		goto out;

	switch (cmd) {
	case AUFS_CTL_RDU:
		err = au_rdu(file, &rdu);
		if (unlikely(err))
			break;

		e = copy_to_user(p, &rdu, sizeof(rdu));
		if (unlikely(e)) {
			err = -EFAULT;
			AuTraceErr(err);
		}
		break;
	case AUFS_CTL_RDU_INO:
		err = au_rdu_ino(file, &rdu);
		break;

	default:
		/* err = -ENOTTY; */
		err = -EINVAL;
	}

out:
	AuTraceErr(err);
	return err;
}

#ifdef CONFIG_COMPAT
long au_rdu_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	long err, e;
	struct aufs_rdu rdu;
	void __user *p = compat_ptr(arg);

	/* todo: get_user()? */
	err = copy_from_user(&rdu, p, sizeof(rdu));
	if (unlikely(err)) {
		err = -EFAULT;
		AuTraceErr(err);
		goto out;
	}
	rdu.ent.e = compat_ptr(rdu.ent.ul);
	err = au_rdu_verify(&rdu);
	if (unlikely(err))
		goto out;

	switch (cmd) {
	case AUFS_CTL_RDU:
		err = au_rdu(file, &rdu);
		if (unlikely(err))
			break;

		rdu.ent.ul = ptr_to_compat(rdu.ent.e);
		rdu.tail.ul = ptr_to_compat(rdu.tail.e);
		e = copy_to_user(p, &rdu, sizeof(rdu));
		if (unlikely(e)) {
			err = -EFAULT;
			AuTraceErr(err);
		}
		break;
	case AUFS_CTL_RDU_INO:
		err = au_rdu_ino(file, &rdu);
		break;

	default:
		/* err = -ENOTTY; */
		err = -EINVAL;
	}

out:
	AuTraceErr(err);
	return err;
}
#endif