freebsd-dev/lib/libc/gen/fts-compat.h
Yaroslav Tykhiy 48aaad5fbc Our fts(3) API, as inherited from 4.4BSD, suffers from integer
fields in FTS and FTSENT structs being too narrow.  In addition,
the narrow types creep from there into fts.c.  As a result, fts(3)
consumers, e.g., find(1) or rm(1), can't handle file trees an ordinary
user can create, which can have security implications.

To fix the historic implementation of fts(3), OpenBSD and NetBSD
have already changed <fts.h> in somewhat incompatible ways, so we
are free to do so, too.  This change is a superset of changes from
the other BSDs with a few more improvements.  It doesn't touch
fts(3) functionality; it just extends integer types used by it to
match modern reality and the C standard.

Here are its points:

o For C object sizes, use size_t unless it's 100% certain that
  the object will be really small.  (Note that fts(3) can construct
  pathnames _much_ longer than PATH_MAX for its consumers.)

o Avoid the short types because on modern platforms using them
  results in larger and slower code.  Change shorts to ints as
  follows:

	- For variables than count simple, limited things like states,
	  use plain vanilla `int' as it's the type of choice in C.

	- For a limited number of bit flags use `unsigned' because signed
	  bit-wise operations are implementation-defined, i.e., unportable,
	  in C.

o For things that should be at least 64 bits wide, use long long
  and not int64_t, as the latter is an optional type.  See
  FTSENT.fts_number aka FTS.fts_bignum.  Extending fts_number `to
  satisfy future needs' is pointless because there is fts_pointer,
  which can be used to link to arbitrary data from an FTSENT.
  However, there already are fts(3) consumers that require fts_number,
  or fts_bignum, have at least 64 bits in it, so we must allow for them.

o For the tree depth, use `long'.  This is a trade-off between making
  this field too wide and allowing for 64-bit inode numbers and/or
  chain-mounted filesystems.  On the one hand, `long' is almost
  enough for 32-bit filesystems on a 32-bit platform (our ino_t is
  uint32_t now).  On the other hand, platforms with a 64-bit (or
  wider) `long' will be ready for 64-bit inode numbers, as well as
  for several 32-bit filesystems mounted one under another.  Note
  that fts_level has to be signed because -1 is a magic value for it,
  FTS_ROOTPARENTLEVEL.

o For the `nlinks' local var in fts_build(), use `long'.  The logic
  in fts_build() requires that `nlinks' be signed, but our nlink_t
  currently is uint16_t.  Therefore let's make the signed var wide
  enough to be able to represent 2^16-1 in pure C99, and even 2^32-1
  on a 64-bit platform.  Perhaps the logic should be changed just
  to use nlink_t, but it can be done later w/o breaking fts(3) ABI
  any more because `nlinks' is just a local var.

This commit also inludes supporting stuff for the fts change:

o Preserve the old versions of fts(3) functions through libc symbol
versioning because the old versions appeared in all our former releases.

o Bump __FreeBSD_version just in case.  There is a small chance that
some ill-written 3-rd party apps may fail to build or work correctly
if compiled after this change.

o Update the fts(3) manpage accordingly.  In particular, remove
references to fts_bignum, which was a FreeBSD-specific hack to work
around the too narrow types of FTSENT members.  Now fts_number is
at least 64 bits wide (long long) and fts_bignum is an undocumented
alias for fts_number kept around for compatibility reasons.  According
to Google Code Search, the only big consumers of fts_bignum are in
our own source tree, so they can be fixed easily to use fts_number.

o Mention the change in src/UPDATING.

PR:		bin/104458
Approved by:	re (quite a while ago)
Discussed with:	deischen (the symbol versioning part)
Reviewed by:	-arch (mostly silence); das (generally OK, but we didn't
		agree on some types used; assuming that no objections on
		-arch let me to stick to my opinion)
2008-01-26 17:09:40 +00:00

133 lines
5.5 KiB
C

/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fts.h 8.3 (Berkeley) 8/14/94
* $FreeBSD$
*/
#ifndef _FTS_H_
#define _FTS_H_
typedef struct {
struct _ftsent *fts_cur; /* current node */
struct _ftsent *fts_child; /* linked list of children */
struct _ftsent **fts_array; /* sort array */
dev_t fts_dev; /* starting device # */
char *fts_path; /* path for this descent */
int fts_rfd; /* fd for root */
int fts_pathlen; /* sizeof(path) */
int fts_nitems; /* elements in the sort array */
int (*fts_compar) /* compare function */
(const struct _ftsent * const *, const struct _ftsent * const *);
#define FTS_COMFOLLOW 0x001 /* follow command line symlinks */
#define FTS_LOGICAL 0x002 /* logical walk */
#define FTS_NOCHDIR 0x004 /* don't change directories */
#define FTS_NOSTAT 0x008 /* don't get stat info */
#define FTS_PHYSICAL 0x010 /* physical walk */
#define FTS_SEEDOT 0x020 /* return dot and dot-dot */
#define FTS_XDEV 0x040 /* don't cross devices */
#define FTS_WHITEOUT 0x080 /* return whiteout information */
#define FTS_OPTIONMASK 0x0ff /* valid user option mask */
#define FTS_NAMEONLY 0x100 /* (private) child names only */
#define FTS_STOP 0x200 /* (private) unrecoverable error */
int fts_options; /* fts_open options, global flags */
void *fts_clientptr; /* thunk for sort function */
} FTS;
typedef struct _ftsent {
struct _ftsent *fts_cycle; /* cycle node */
struct _ftsent *fts_parent; /* parent directory */
struct _ftsent *fts_link; /* next file in directory */
union {
struct {
long __fts_number; /* local numeric value */
void *__fts_pointer; /* local address value */
} __struct_ftsent;
int64_t __fts_bignum;
} __union_ftsent;
#define fts_number __union_ftsent.__struct_ftsent.__fts_number
#define fts_pointer __union_ftsent.__struct_ftsent.__fts_pointer
#define fts_bignum __union_ftsent.__fts_bignum
char *fts_accpath; /* access path */
char *fts_path; /* root path */
int fts_errno; /* errno for this node */
int fts_symfd; /* fd for symlink */
u_short fts_pathlen; /* strlen(fts_path) */
u_short fts_namelen; /* strlen(fts_name) */
ino_t fts_ino; /* inode */
dev_t fts_dev; /* device */
nlink_t fts_nlink; /* link count */
#define FTS_ROOTPARENTLEVEL -1
#define FTS_ROOTLEVEL 0
short fts_level; /* depth (-1 to N) */
#define FTS_D 1 /* preorder directory */
#define FTS_DC 2 /* directory that causes cycles */
#define FTS_DEFAULT 3 /* none of the above */
#define FTS_DNR 4 /* unreadable directory */
#define FTS_DOT 5 /* dot or dot-dot */
#define FTS_DP 6 /* postorder directory */
#define FTS_ERR 7 /* error; errno is set */
#define FTS_F 8 /* regular file */
#define FTS_INIT 9 /* initialized only */
#define FTS_NS 10 /* stat(2) failed */
#define FTS_NSOK 11 /* no stat(2) requested */
#define FTS_SL 12 /* symbolic link */
#define FTS_SLNONE 13 /* symbolic link without target */
#define FTS_W 14 /* whiteout object */
u_short fts_info; /* user flags for FTSENT structure */
#define FTS_DONTCHDIR 0x01 /* don't chdir .. to the parent */
#define FTS_SYMFOLLOW 0x02 /* followed a symlink to get here */
#define FTS_ISW 0x04 /* this is a whiteout object */
u_short fts_flags; /* private flags for FTSENT structure */
#define FTS_AGAIN 1 /* read node again */
#define FTS_FOLLOW 2 /* follow symbolic link */
#define FTS_NOINSTR 3 /* no instructions */
#define FTS_SKIP 4 /* discard node */
u_short fts_instr; /* fts_set() instructions */
struct stat *fts_statp; /* stat(2) information */
char *fts_name; /* file name */
FTS *fts_fts; /* back pointer to main FTS */
} FTSENT;
#define fts_get_clientptr(fts) ((fts)->fts_clientptr)
#define fts_get_stream(ftsent) ((ftsent)->fts_fts)
#endif /* !_FTS_H_ */