readdir.c revision 3998f0b8
1// SPDX-License-Identifier: LGPL-2.1
2/*
3 *   fs/cifs/readdir.c
4 *
5 *   Directory search handling
6 *
7 *   Copyright (C) International Business Machines  Corp., 2004, 2008
8 *   Copyright (C) Red Hat, Inc., 2011
9 *   Author(s): Steve French (sfrench@us.ibm.com)
10 *
11 */
12#include <linux/fs.h>
13#include <linux/pagemap.h>
14#include <linux/slab.h>
15#include <linux/stat.h>
16#include "cifspdu.h"
17#include "cifsglob.h"
18#include "cifsproto.h"
19#include "cifs_unicode.h"
20#include "cifs_debug.h"
21#include "cifs_fs_sb.h"
22#include "cifsfs.h"
23#include "smb2proto.h"
24#include "fs_context.h"
25
26/*
27 * To be safe - for UCS to UTF-8 with strings loaded with the rare long
28 * characters alloc more to account for such multibyte target UTF-8
29 * characters.
30 */
31#define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
32
33#ifdef CONFIG_CIFS_DEBUG2
34static void dump_cifs_file_struct(struct file *file, char *label)
35{
36	struct cifsFileInfo *cf;
37
38	if (file) {
39		cf = file->private_data;
40		if (cf == NULL) {
41			cifs_dbg(FYI, "empty cifs private file data\n");
42			return;
43		}
44		if (cf->invalidHandle)
45			cifs_dbg(FYI, "Invalid handle\n");
46		if (cf->srch_inf.endOfSearch)
47			cifs_dbg(FYI, "end of search\n");
48		if (cf->srch_inf.emptyDir)
49			cifs_dbg(FYI, "empty dir\n");
50	}
51}
52#else
53static inline void dump_cifs_file_struct(struct file *file, char *label)
54{
55}
56#endif /* DEBUG2 */
57
58/*
59 * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
60 *
61 * Find the dentry that matches "name". If there isn't one, create one. If it's
62 * a negative dentry or the uniqueid or filetype(mode) changed,
63 * then drop it and recreate it.
64 */
65static void
66cifs_prime_dcache(struct dentry *parent, struct qstr *name,
67		    struct cifs_fattr *fattr)
68{
69	struct dentry *dentry, *alias;
70	struct inode *inode;
71	struct super_block *sb = parent->d_sb;
72	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
73	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
74
75	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
76
77	dentry = d_hash_and_lookup(parent, name);
78	if (!dentry) {
79		/*
80		 * If we know that the inode will need to be revalidated
81		 * immediately, then don't create a new dentry for it.
82		 * We'll end up doing an on the wire call either way and
83		 * this spares us an invalidation.
84		 */
85		if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
86			return;
87retry:
88		dentry = d_alloc_parallel(parent, name, &wq);
89	}
90	if (IS_ERR(dentry))
91		return;
92	if (!d_in_lookup(dentry)) {
93		inode = d_inode(dentry);
94		if (inode) {
95			if (d_mountpoint(dentry)) {
96				dput(dentry);
97				return;
98			}
99			/*
100			 * If we're generating inode numbers, then we don't
101			 * want to clobber the existing one with the one that
102			 * the readdir code created.
103			 */
104			if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
105				fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
106
107			/* update inode in place
108			 * if both i_ino and i_mode didn't change */
109			if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
110			    cifs_fattr_to_inode(inode, fattr) == 0) {
111				dput(dentry);
112				return;
113			}
114		}
115		d_invalidate(dentry);
116		dput(dentry);
117		goto retry;
118	} else {
119		inode = cifs_iget(sb, fattr);
120		if (!inode)
121			inode = ERR_PTR(-ENOMEM);
122		alias = d_splice_alias(inode, dentry);
123		d_lookup_done(dentry);
124		if (alias && !IS_ERR(alias))
125			dput(alias);
126	}
127	dput(dentry);
128}
129
130static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
131{
132	if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
133		return false;
134	/*
135	 * The DFS tags should be only intepreted by server side as per
136	 * MS-FSCC 2.1.2.1, but let's include them anyway.
137	 *
138	 * Besides, if cf_cifstag is unset (0), then we still need it to be
139	 * revalidated to know exactly what reparse point it is.
140	 */
141	switch (fattr->cf_cifstag) {
142	case IO_REPARSE_TAG_DFS:
143	case IO_REPARSE_TAG_DFSR:
144	case IO_REPARSE_TAG_SYMLINK:
145	case IO_REPARSE_TAG_NFS:
146	case 0:
147		return true;
148	}
149	return false;
150}
151
152static void
153cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
154{
155	fattr->cf_uid = cifs_sb->ctx->linux_uid;
156	fattr->cf_gid = cifs_sb->ctx->linux_gid;
157
158	/*
159	 * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
160	 * are preferred by the Linux client in some cases since, unlike
161	 * the NFS reparse tag (or EAs), they don't require an extra query
162	 * to determine which type of special file they represent.
163	 * TODO: go through all documented  reparse tags to see if we can
164	 * reasonably map some of them to directories vs. files vs. symlinks
165	 */
166	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
167		fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
168		fattr->cf_dtype = DT_DIR;
169	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_SYMLINK) {
170		fattr->cf_mode |= S_IFLNK | cifs_sb->ctx->file_mode;
171		fattr->cf_dtype = DT_LNK;
172	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_FIFO) {
173		fattr->cf_mode |= S_IFIFO | cifs_sb->ctx->file_mode;
174		fattr->cf_dtype = DT_FIFO;
175	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_AF_UNIX) {
176		fattr->cf_mode |= S_IFSOCK | cifs_sb->ctx->file_mode;
177		fattr->cf_dtype = DT_SOCK;
178	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_CHR) {
179		fattr->cf_mode |= S_IFCHR | cifs_sb->ctx->file_mode;
180		fattr->cf_dtype = DT_CHR;
181	} else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_BLK) {
182		fattr->cf_mode |= S_IFBLK | cifs_sb->ctx->file_mode;
183		fattr->cf_dtype = DT_BLK;
184	} else { /* TODO: should we mark some other reparse points (like DFSR) as directories? */
185		fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
186		fattr->cf_dtype = DT_REG;
187	}
188
189	/*
190	 * We need to revalidate it further to make a decision about whether it
191	 * is a symbolic link, DFS referral or a reparse point with a direct
192	 * access like junctions, deduplicated files, NFS symlinks.
193	 */
194	if (reparse_file_needs_reval(fattr))
195		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
196
197	/* non-unix readdir doesn't provide nlink */
198	fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
199
200	if (fattr->cf_cifsattrs & ATTR_READONLY)
201		fattr->cf_mode &= ~S_IWUGO;
202
203	/*
204	 * We of course don't get ACL info in FIND_FIRST/NEXT results, so
205	 * mark it for revalidation so that "ls -l" will look right. It might
206	 * be super-slow, but if we don't do this then the ownership of files
207	 * may look wrong since the inodes may not have timed out by the time
208	 * "ls" does a stat() call on them.
209	 */
210	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
211	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
212		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
213
214	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
215	    fattr->cf_cifsattrs & ATTR_SYSTEM) {
216		if (fattr->cf_eof == 0)  {
217			fattr->cf_mode &= ~S_IFMT;
218			fattr->cf_mode |= S_IFIFO;
219			fattr->cf_dtype = DT_FIFO;
220		} else {
221			/*
222			 * trying to get the type and mode via SFU can be slow,
223			 * so just call those regular files for now, and mark
224			 * for reval
225			 */
226			fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
227		}
228	}
229}
230
231/* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
232static void
233cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
234		    struct cifs_sb_info *cifs_sb)
235{
236	struct smb2_posix_info_parsed parsed;
237
238	posix_info_parse(info, NULL, &parsed);
239
240	memset(fattr, 0, sizeof(*fattr));
241	fattr->cf_uniqueid = le64_to_cpu(info->Inode);
242	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
243	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
244
245	fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
246	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
247	fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
248
249	fattr->cf_nlink = le32_to_cpu(info->HardLinks);
250	fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
251
252	/*
253	 * Since we set the inode type below we need to mask off
254	 * to avoid strange results if bits set above.
255	 * XXX: why not make server&client use the type bits?
256	 */
257	fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
258
259	cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
260		 le32_to_cpu(info->DeviceId),
261		 le32_to_cpu(info->ReparseTag),
262		 le32_to_cpu(info->Mode));
263
264	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
265		fattr->cf_mode |= S_IFDIR;
266		fattr->cf_dtype = DT_DIR;
267	} else {
268		/*
269		 * mark anything that is not a dir as regular
270		 * file. special files should have the REPARSE
271		 * attribute and will be marked as needing revaluation
272		 */
273		fattr->cf_mode |= S_IFREG;
274		fattr->cf_dtype = DT_REG;
275	}
276
277	if (reparse_file_needs_reval(fattr))
278		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
279
280	sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
281	sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
282}
283
284static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
285{
286	const FILE_DIRECTORY_INFO *fi = info;
287
288	memset(fattr, 0, sizeof(*fattr));
289	fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
290	fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
291	fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
292	fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
293	fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
294	fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
295	fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
296}
297
298void
299cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
300		       struct cifs_sb_info *cifs_sb)
301{
302	__dir_info_to_fattr(fattr, info);
303	cifs_fill_common_info(fattr, cifs_sb);
304}
305
306static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
307				       SEARCH_ID_FULL_DIR_INFO *info,
308				       struct cifs_sb_info *cifs_sb)
309{
310	__dir_info_to_fattr(fattr, info);
311
312	/* See MS-FSCC 2.4.19 FileIdFullDirectoryInformation */
313	if (fattr->cf_cifsattrs & ATTR_REPARSE)
314		fattr->cf_cifstag = le32_to_cpu(info->EaSize);
315	cifs_fill_common_info(fattr, cifs_sb);
316}
317
318static void
319cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
320		       struct cifs_sb_info *cifs_sb)
321{
322	int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
323
324	memset(fattr, 0, sizeof(*fattr));
325	fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
326					    info->LastAccessTime, offset);
327	fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
328					    info->LastWriteTime, offset);
329	fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
330					    info->LastWriteTime, offset);
331
332	fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
333	fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
334	fattr->cf_eof = le32_to_cpu(info->DataSize);
335
336	cifs_fill_common_info(fattr, cifs_sb);
337}
338
339/* BB eventually need to add the following helper function to
340      resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
341      we try to do FindFirst on (NTFS) directory symlinks */
342/*
343int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
344			     unsigned int xid)
345{
346	__u16 fid;
347	int len;
348	int oplock = 0;
349	int rc;
350	struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
351	char *tmpbuffer;
352
353	rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
354			OPEN_REPARSE_POINT, &fid, &oplock, NULL,
355			cifs_sb->local_nls,
356			cifs_remap(cifs_sb);
357	if (!rc) {
358		tmpbuffer = kmalloc(maxpath);
359		rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
360				tmpbuffer,
361				maxpath -1,
362				fid,
363				cifs_sb->local_nls);
364		if (CIFSSMBClose(xid, ptcon, fid)) {
365			cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
366		}
367	}
368}
369 */
370
371static int
372_initiate_cifs_search(const unsigned int xid, struct file *file,
373		     const char *full_path)
374{
375	__u16 search_flags;
376	int rc = 0;
377	struct cifsFileInfo *cifsFile;
378	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
379	struct tcon_link *tlink = NULL;
380	struct cifs_tcon *tcon;
381	struct TCP_Server_Info *server;
382
383	if (file->private_data == NULL) {
384		tlink = cifs_sb_tlink(cifs_sb);
385		if (IS_ERR(tlink))
386			return PTR_ERR(tlink);
387
388		cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
389		if (cifsFile == NULL) {
390			rc = -ENOMEM;
391			goto error_exit;
392		}
393		spin_lock_init(&cifsFile->file_info_lock);
394		file->private_data = cifsFile;
395		cifsFile->tlink = cifs_get_tlink(tlink);
396		tcon = tlink_tcon(tlink);
397	} else {
398		cifsFile = file->private_data;
399		tcon = tlink_tcon(cifsFile->tlink);
400	}
401
402	server = tcon->ses->server;
403
404	if (!server->ops->query_dir_first) {
405		rc = -ENOSYS;
406		goto error_exit;
407	}
408
409	cifsFile->invalidHandle = true;
410	cifsFile->srch_inf.endOfSearch = false;
411
412	cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
413
414ffirst_retry:
415	/* test for Unix extensions */
416	/* but now check for them on the share/mount not on the SMB session */
417	/* if (cap_unix(tcon->ses) { */
418	if (tcon->unix_ext)
419		cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
420	else if (tcon->posix_extensions)
421		cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
422	else if ((tcon->ses->capabilities &
423		  tcon->ses->server->vals->cap_nt_find) == 0) {
424		cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
425	} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
426		cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
427	} else /* not srvinos - BB fixme add check for backlevel? */ {
428		cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
429	}
430
431	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
432	if (backup_cred(cifs_sb))
433		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
434
435	rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
436					  &cifsFile->fid, search_flags,
437					  &cifsFile->srch_inf);
438
439	if (rc == 0)
440		cifsFile->invalidHandle = false;
441	/* BB add following call to handle readdir on new NTFS symlink errors
442	else if STATUS_STOPPED_ON_SYMLINK
443		call get_symlink_reparse_path and retry with new path */
444	else if ((rc == -EOPNOTSUPP) &&
445		(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
446		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
447		goto ffirst_retry;
448	}
449error_exit:
450	cifs_put_tlink(tlink);
451	return rc;
452}
453
454static int
455initiate_cifs_search(const unsigned int xid, struct file *file,
456		     const char *full_path)
457{
458	int rc, retry_count = 0;
459
460	do {
461		rc = _initiate_cifs_search(xid, file, full_path);
462		/*
463		 * If we don't have enough credits to start reading the
464		 * directory just try again after short wait.
465		 */
466		if (rc != -EDEADLK)
467			break;
468
469		usleep_range(512, 2048);
470	} while (retry_count++ < 5);
471
472	return rc;
473}
474
475/* return length of unicode string in bytes */
476static int cifs_unicode_bytelen(const char *str)
477{
478	int len;
479	const __le16 *ustr = (const __le16 *)str;
480
481	for (len = 0; len <= PATH_MAX; len++) {
482		if (ustr[len] == 0)
483			return len << 1;
484	}
485	cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
486	return len << 1;
487}
488
489static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
490{
491	char *new_entry;
492	FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
493
494	if (level == SMB_FIND_FILE_INFO_STANDARD) {
495		FIND_FILE_STANDARD_INFO *pfData;
496		pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
497
498		new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
499				pfData->FileNameLength;
500	} else {
501		u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
502
503		if (old_entry + next_offset < old_entry) {
504			cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
505			return NULL;
506		}
507		new_entry = old_entry + next_offset;
508	}
509	cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
510	/* validate that new_entry is not past end of SMB */
511	if (new_entry >= end_of_smb) {
512		cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
513			 new_entry, end_of_smb, old_entry);
514		return NULL;
515	} else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
516		    (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
517		  || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
518		   (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
519		cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
520			 new_entry, end_of_smb);
521		return NULL;
522	} else
523		return new_entry;
524
525}
526
527struct cifs_dirent {
528	const char	*name;
529	size_t		namelen;
530	u32		resume_key;
531	u64		ino;
532};
533
534static void cifs_fill_dirent_posix(struct cifs_dirent *de,
535				   const struct smb2_posix_info *info)
536{
537	struct smb2_posix_info_parsed parsed;
538
539	/* payload should have already been checked at this point */
540	if (posix_info_parse(info, NULL, &parsed) < 0) {
541		cifs_dbg(VFS, "Invalid POSIX info payload\n");
542		return;
543	}
544
545	de->name = parsed.name;
546	de->namelen = parsed.name_len;
547	de->resume_key = info->Ignored;
548	de->ino = le64_to_cpu(info->Inode);
549}
550
551static void cifs_fill_dirent_unix(struct cifs_dirent *de,
552		const FILE_UNIX_INFO *info, bool is_unicode)
553{
554	de->name = &info->FileName[0];
555	if (is_unicode)
556		de->namelen = cifs_unicode_bytelen(de->name);
557	else
558		de->namelen = strnlen(de->name, PATH_MAX);
559	de->resume_key = info->ResumeKey;
560	de->ino = le64_to_cpu(info->basic.UniqueId);
561}
562
563static void cifs_fill_dirent_dir(struct cifs_dirent *de,
564		const FILE_DIRECTORY_INFO *info)
565{
566	de->name = &info->FileName[0];
567	de->namelen = le32_to_cpu(info->FileNameLength);
568	de->resume_key = info->FileIndex;
569}
570
571static void cifs_fill_dirent_full(struct cifs_dirent *de,
572		const FILE_FULL_DIRECTORY_INFO *info)
573{
574	de->name = &info->FileName[0];
575	de->namelen = le32_to_cpu(info->FileNameLength);
576	de->resume_key = info->FileIndex;
577}
578
579static void cifs_fill_dirent_search(struct cifs_dirent *de,
580		const SEARCH_ID_FULL_DIR_INFO *info)
581{
582	de->name = &info->FileName[0];
583	de->namelen = le32_to_cpu(info->FileNameLength);
584	de->resume_key = info->FileIndex;
585	de->ino = le64_to_cpu(info->UniqueId);
586}
587
588static void cifs_fill_dirent_both(struct cifs_dirent *de,
589		const FILE_BOTH_DIRECTORY_INFO *info)
590{
591	de->name = &info->FileName[0];
592	de->namelen = le32_to_cpu(info->FileNameLength);
593	de->resume_key = info->FileIndex;
594}
595
596static void cifs_fill_dirent_std(struct cifs_dirent *de,
597		const FIND_FILE_STANDARD_INFO *info)
598{
599	de->name = &info->FileName[0];
600	/* one byte length, no endianess conversion */
601	de->namelen = info->FileNameLength;
602	de->resume_key = info->ResumeKey;
603}
604
605static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
606		u16 level, bool is_unicode)
607{
608	memset(de, 0, sizeof(*de));
609
610	switch (level) {
611	case SMB_FIND_FILE_POSIX_INFO:
612		cifs_fill_dirent_posix(de, info);
613		break;
614	case SMB_FIND_FILE_UNIX:
615		cifs_fill_dirent_unix(de, info, is_unicode);
616		break;
617	case SMB_FIND_FILE_DIRECTORY_INFO:
618		cifs_fill_dirent_dir(de, info);
619		break;
620	case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
621		cifs_fill_dirent_full(de, info);
622		break;
623	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
624		cifs_fill_dirent_search(de, info);
625		break;
626	case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
627		cifs_fill_dirent_both(de, info);
628		break;
629	case SMB_FIND_FILE_INFO_STANDARD:
630		cifs_fill_dirent_std(de, info);
631		break;
632	default:
633		cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
634		return -EINVAL;
635	}
636
637	return 0;
638}
639
640#define UNICODE_DOT cpu_to_le16(0x2e)
641
642/* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
643static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
644{
645	int rc = 0;
646
647	if (!de->name)
648		return 0;
649
650	if (is_unicode) {
651		__le16 *ufilename = (__le16 *)de->name;
652		if (de->namelen == 2) {
653			/* check for . */
654			if (ufilename[0] == UNICODE_DOT)
655				rc = 1;
656		} else if (de->namelen == 4) {
657			/* check for .. */
658			if (ufilename[0] == UNICODE_DOT &&
659			    ufilename[1] == UNICODE_DOT)
660				rc = 2;
661		}
662	} else /* ASCII */ {
663		if (de->namelen == 1) {
664			if (de->name[0] == '.')
665				rc = 1;
666		} else if (de->namelen == 2) {
667			if (de->name[0] == '.' && de->name[1] == '.')
668				rc = 2;
669		}
670	}
671
672	return rc;
673}
674
675/* Check if directory that we are searching has changed so we can decide
676   whether we can use the cached search results from the previous search */
677static int is_dir_changed(struct file *file)
678{
679	struct inode *inode = file_inode(file);
680	struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
681
682	if (cifsInfo->time == 0)
683		return 1; /* directory was changed, perhaps due to unlink */
684	else
685		return 0;
686
687}
688
689static int cifs_save_resume_key(const char *current_entry,
690	struct cifsFileInfo *file_info)
691{
692	struct cifs_dirent de;
693	int rc;
694
695	rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
696			      file_info->srch_inf.unicode);
697	if (!rc) {
698		file_info->srch_inf.presume_name = de.name;
699		file_info->srch_inf.resume_name_len = de.namelen;
700		file_info->srch_inf.resume_key = de.resume_key;
701	}
702	return rc;
703}
704
705/*
706 * Find the corresponding entry in the search. Note that the SMB server returns
707 * search entries for . and .. which complicates logic here if we choose to
708 * parse for them and we do not assume that they are located in the findfirst
709 * return buffer. We start counting in the buffer with entry 2 and increment for
710 * every entry (do not increment for . or .. entry).
711 */
712static int
713find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
714		struct file *file, const char *full_path,
715		char **current_entry, int *num_to_ret)
716{
717	__u16 search_flags;
718	int rc = 0;
719	int pos_in_buf = 0;
720	loff_t first_entry_in_buffer;
721	loff_t index_to_find = pos;
722	struct cifsFileInfo *cfile = file->private_data;
723	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
724	struct TCP_Server_Info *server = tcon->ses->server;
725	/* check if index in the buffer */
726
727	if (!server->ops->query_dir_first || !server->ops->query_dir_next)
728		return -ENOSYS;
729
730	if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
731		return -ENOENT;
732
733	*current_entry = NULL;
734	first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
735					cfile->srch_inf.entries_in_buffer;
736
737	/*
738	 * If first entry in buf is zero then is first buffer
739	 * in search response data which means it is likely . and ..
740	 * will be in this buffer, although some servers do not return
741	 * . and .. for the root of a drive and for those we need
742	 * to start two entries earlier.
743	 */
744
745	dump_cifs_file_struct(file, "In fce ");
746	if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
747	     is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
748		/* close and restart search */
749		cifs_dbg(FYI, "search backing up - close and restart search\n");
750		spin_lock(&cfile->file_info_lock);
751		if (server->ops->dir_needs_close(cfile)) {
752			cfile->invalidHandle = true;
753			spin_unlock(&cfile->file_info_lock);
754			if (server->ops->close_dir)
755				server->ops->close_dir(xid, tcon, &cfile->fid);
756		} else
757			spin_unlock(&cfile->file_info_lock);
758		if (cfile->srch_inf.ntwrk_buf_start) {
759			cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
760			if (cfile->srch_inf.smallBuf)
761				cifs_small_buf_release(cfile->srch_inf.
762						ntwrk_buf_start);
763			else
764				cifs_buf_release(cfile->srch_inf.
765						ntwrk_buf_start);
766			cfile->srch_inf.ntwrk_buf_start = NULL;
767		}
768		rc = initiate_cifs_search(xid, file, full_path);
769		if (rc) {
770			cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
771				 rc);
772			return rc;
773		}
774		/* FindFirst/Next set last_entry to NULL on malformed reply */
775		if (cfile->srch_inf.last_entry)
776			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
777	}
778
779	search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
780	if (backup_cred(cifs_sb))
781		search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
782
783	while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
784	       (rc == 0) && !cfile->srch_inf.endOfSearch) {
785		cifs_dbg(FYI, "calling findnext2\n");
786		rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
787						 search_flags,
788						 &cfile->srch_inf);
789		/* FindFirst/Next set last_entry to NULL on malformed reply */
790		if (cfile->srch_inf.last_entry)
791			cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
792		if (rc)
793			return -ENOENT;
794	}
795	if (index_to_find < cfile->srch_inf.index_of_last_entry) {
796		/* we found the buffer that contains the entry */
797		/* scan and find it */
798		int i;
799		char *cur_ent;
800		char *end_of_smb;
801
802		if (cfile->srch_inf.ntwrk_buf_start == NULL) {
803			cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
804			return -EIO;
805		}
806
807		end_of_smb = cfile->srch_inf.ntwrk_buf_start +
808			server->ops->calc_smb_size(
809					cfile->srch_inf.ntwrk_buf_start,
810					server);
811
812		cur_ent = cfile->srch_inf.srch_entries_start;
813		first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
814					- cfile->srch_inf.entries_in_buffer;
815		pos_in_buf = index_to_find - first_entry_in_buffer;
816		cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
817
818		for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
819			/* go entry by entry figuring out which is first */
820			cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
821						cfile->srch_inf.info_level);
822		}
823		if ((cur_ent == NULL) && (i < pos_in_buf)) {
824			/* BB fixme - check if we should flag this error */
825			cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
826				 pos_in_buf, index_to_find, rc);
827		}
828		rc = 0;
829		*current_entry = cur_ent;
830	} else {
831		cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
832		return 0;
833	}
834
835	if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
836		cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
837		*num_to_ret = 0;
838	} else
839		*num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
840
841	return rc;
842}
843
844static int cifs_filldir(char *find_entry, struct file *file,
845		struct dir_context *ctx,
846		char *scratch_buf, unsigned int max_len)
847{
848	struct cifsFileInfo *file_info = file->private_data;
849	struct super_block *sb = file_inode(file)->i_sb;
850	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
851	struct cifs_dirent de = { NULL, };
852	struct cifs_fattr fattr;
853	struct qstr name;
854	int rc = 0;
855	ino_t ino;
856
857	rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
858			      file_info->srch_inf.unicode);
859	if (rc)
860		return rc;
861
862	if (de.namelen > max_len) {
863		cifs_dbg(VFS, "bad search response length %zd past smb end\n",
864			 de.namelen);
865		return -EINVAL;
866	}
867
868	/* skip . and .. since we added them first */
869	if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
870		return 0;
871
872	if (file_info->srch_inf.unicode) {
873		struct nls_table *nlt = cifs_sb->local_nls;
874		int map_type;
875
876		map_type = cifs_remap(cifs_sb);
877		name.name = scratch_buf;
878		name.len =
879			cifs_from_utf16((char *)name.name, (__le16 *)de.name,
880					UNICODE_NAME_MAX,
881					min_t(size_t, de.namelen,
882					      (size_t)max_len), nlt, map_type);
883		name.len -= nls_nullsize(nlt);
884	} else {
885		name.name = de.name;
886		name.len = de.namelen;
887	}
888
889	switch (file_info->srch_inf.info_level) {
890	case SMB_FIND_FILE_POSIX_INFO:
891		cifs_posix_to_fattr(&fattr,
892				    (struct smb2_posix_info *)find_entry,
893				    cifs_sb);
894		break;
895	case SMB_FIND_FILE_UNIX:
896		cifs_unix_basic_to_fattr(&fattr,
897					 &((FILE_UNIX_INFO *)find_entry)->basic,
898					 cifs_sb);
899		break;
900	case SMB_FIND_FILE_INFO_STANDARD:
901		cifs_std_info_to_fattr(&fattr,
902				       (FIND_FILE_STANDARD_INFO *)find_entry,
903				       cifs_sb);
904		break;
905	case SMB_FIND_FILE_ID_FULL_DIR_INFO:
906		cifs_fulldir_info_to_fattr(&fattr,
907					   (SEARCH_ID_FULL_DIR_INFO *)find_entry,
908					   cifs_sb);
909		break;
910	default:
911		cifs_dir_info_to_fattr(&fattr,
912				       (FILE_DIRECTORY_INFO *)find_entry,
913				       cifs_sb);
914		break;
915	}
916
917	if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
918		fattr.cf_uniqueid = de.ino;
919	} else {
920		fattr.cf_uniqueid = iunique(sb, ROOT_I);
921		cifs_autodisable_serverino(cifs_sb);
922	}
923
924	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
925	    couldbe_mf_symlink(&fattr))
926		/*
927		 * trying to get the type and mode can be slow,
928		 * so just call those regular files for now, and mark
929		 * for reval
930		 */
931		fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
932
933	cifs_prime_dcache(file_dentry(file), &name, &fattr);
934
935	ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
936	return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
937}
938
939
940int cifs_readdir(struct file *file, struct dir_context *ctx)
941{
942	int rc = 0;
943	unsigned int xid;
944	int i;
945	struct cifs_tcon *tcon;
946	struct cifsFileInfo *cifsFile = NULL;
947	char *current_entry;
948	int num_to_fill = 0;
949	char *tmp_buf = NULL;
950	char *end_of_smb;
951	unsigned int max_len;
952	const char *full_path;
953	void *page = alloc_dentry_path();
954
955	xid = get_xid();
956
957	full_path = build_path_from_dentry(file_dentry(file), page);
958	if (IS_ERR(full_path)) {
959		rc = PTR_ERR(full_path);
960		goto rddir2_exit;
961	}
962
963	/*
964	 * Ensure FindFirst doesn't fail before doing filldir() for '.' and
965	 * '..'. Otherwise we won't be able to notify VFS in case of failure.
966	 */
967	if (file->private_data == NULL) {
968		rc = initiate_cifs_search(xid, file, full_path);
969		cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
970		if (rc)
971			goto rddir2_exit;
972	}
973
974	if (!dir_emit_dots(file, ctx))
975		goto rddir2_exit;
976
977	/* 1) If search is active,
978		is in current search buffer?
979		if it before then restart search
980		if after then keep searching till find it */
981
982	cifsFile = file->private_data;
983	if (cifsFile->srch_inf.endOfSearch) {
984		if (cifsFile->srch_inf.emptyDir) {
985			cifs_dbg(FYI, "End of search, empty dir\n");
986			rc = 0;
987			goto rddir2_exit;
988		}
989	} /* else {
990		cifsFile->invalidHandle = true;
991		tcon->ses->server->close(xid, tcon, &cifsFile->fid);
992	} */
993
994	tcon = tlink_tcon(cifsFile->tlink);
995	rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
996			     &current_entry, &num_to_fill);
997	if (rc) {
998		cifs_dbg(FYI, "fce error %d\n", rc);
999		goto rddir2_exit;
1000	} else if (current_entry != NULL) {
1001		cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
1002	} else {
1003		cifs_dbg(FYI, "Could not find entry\n");
1004		goto rddir2_exit;
1005	}
1006	cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
1007		 num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
1008	max_len = tcon->ses->server->ops->calc_smb_size(
1009			cifsFile->srch_inf.ntwrk_buf_start,
1010			tcon->ses->server);
1011	end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1012
1013	tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1014	if (tmp_buf == NULL) {
1015		rc = -ENOMEM;
1016		goto rddir2_exit;
1017	}
1018
1019	for (i = 0; i < num_to_fill; i++) {
1020		if (current_entry == NULL) {
1021			/* evaluate whether this case is an error */
1022			cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1023				 num_to_fill, i);
1024			break;
1025		}
1026		/*
1027		 * if buggy server returns . and .. late do we want to
1028		 * check for that here?
1029		 */
1030		*tmp_buf = 0;
1031		rc = cifs_filldir(current_entry, file, ctx,
1032				  tmp_buf, max_len);
1033		if (rc) {
1034			if (rc > 0)
1035				rc = 0;
1036			break;
1037		}
1038
1039		ctx->pos++;
1040		if (ctx->pos ==
1041			cifsFile->srch_inf.index_of_last_entry) {
1042			cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1043				 ctx->pos, tmp_buf);
1044			cifs_save_resume_key(current_entry, cifsFile);
1045			break;
1046		} else
1047			current_entry =
1048				nxt_dir_entry(current_entry, end_of_smb,
1049					cifsFile->srch_inf.info_level);
1050	}
1051	kfree(tmp_buf);
1052
1053rddir2_exit:
1054	free_dentry_path(page);
1055	free_xid(xid);
1056	return rc;
1057}
1058