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Make the threatened fts(3) ABI fix. FTSENT now avoids the use of the struct

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hack, thereby allowing future extensions to the structure (e.g., for extended
attributes) without rebreaking the ABI.  FTSENT now contains a pointer to the
parent stream, which fts_compar() can then take advantage of, avoiding the
undefined behavior previously warned about.  As a consequence of this change,
the prototype of the comparison function passed to fts_open() has changed
to reflect the required amount of constness for its use.  All callers in the
tree are updated to use the correct prototype.

Comparison functions can now make use of the new parent pointer to access
the new stream-specific private data pointer, which is intended to assist
creation of reentrant library routines which use fts(3) internally.

Not objected to in spirit by: -arch
This commit is contained in:
Garrett Wollman 2002-09-21 01:28:41 +00:00
parent 0c7fb5347c
commit 0d3bcc2e80
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=103726
11 changed files with 208 additions and 51 deletions
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4
bin/cp/cp.c
View File

@ -92,7 +92,7 @@ static int Rflag, rflag;
enum op { FILE_TO_FILE, FILE_TO_DIR, DIR_TO_DNE };
static int copy(char *[], enum op, int);
static int mastercmp(const FTSENT **, const FTSENT **);
static int mastercmp(const FTSENT * const *, const FTSENT * const *);
int
main(int argc, char *argv[])
@ -484,7 +484,7 @@ copy(char *argv[], enum op type, int fts_options)
* files first reduces seeking.
*/
int
mastercmp(const FTSENT **a, const FTSENT **b)
mastercmp(const FTSENT * const *a, const FTSENT * const *b)
{
int a_info, b_info;

4
bin/ls/ls.c
View File

@ -82,7 +82,7 @@ __FBSDID("$FreeBSD$");
static void display(FTSENT *, FTSENT *);
static u_quad_t makenines(u_long);
static int mastercmp(const FTSENT **, const FTSENT **);
static int mastercmp(const FTSENT * const *, const FTSENT * const *);
static void traverse(int, char **, int);
static void (*printfcn)(DISPLAY *);
@ -759,7 +759,7 @@ display(FTSENT *p, FTSENT *list)
* All other levels use the sort function. Error entries remain unsorted.
*/
static int
mastercmp(const FTSENT **a, const FTSENT **b)
mastercmp(const FTSENT * const *a, const FTSENT * const *b)
{
int a_info, b_info;

13
include/fts.h
View File

@ -47,7 +47,7 @@ typedef struct {
int fts_pathlen; /* sizeof(path) */
int fts_nitems; /* elements in the sort array */
int (*fts_compar) /* compare function */
(const struct _ftsent **, const struct _ftsent **);
(const struct _ftsent * const *, const struct _ftsent * const *);
#define FTS_COMFOLLOW 0x001 /* follow command line symlinks */
#define FTS_LOGICAL 0x002 /* logical walk */
@ -62,6 +62,7 @@ typedef struct {
#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 {
@ -113,7 +114,8 @@ typedef struct _ftsent {
u_short fts_instr; /* fts_set() instructions */
struct stat *fts_statp; /* stat(2) information */
char fts_name[1]; /* file name */
char *fts_name; /* file name */
FTS *fts_fts; /* back pointer to main FTS */
} FTSENT;
#include <sys/cdefs.h>
@ -121,10 +123,15 @@ typedef struct _ftsent {
__BEGIN_DECLS
FTSENT *fts_children(FTS *, int);
int fts_close(FTS *);
void *fts_get_clientptr(FTS *);
#define fts_get_clientptr(fts) ((fts)->fts_clientptr)
FTS *fts_get_stream(FTSENT *);
#define fts_get_stream(ftsent) ((ftsent)->fts_fts)
FTS *fts_open(char * const *, int,
int (*)(const FTSENT **, const FTSENT **));
int (*)(const FTSENT * const *, const FTSENT * const *));
FTSENT *fts_read(FTS *);
int fts_set(FTS *, FTSENT *, int);
void fts_set_clientptr(FTS *, void *);
__END_DECLS
#endif /* !_FTS_H_ */

82
lib/libc/gen/fts-compat.c
View File

@ -81,7 +81,7 @@ FTS *
fts_open(argv, options, compar)
char * const *argv;
int options;
int (*compar)(const FTSENT **, const FTSENT **);
int (*compar)(const FTSENT * const *, const FTSENT * const *);
{
FTS *sp;
FTSENT *p, *root;
@ -96,7 +96,7 @@ fts_open(argv, options, compar)
}
/* Allocate/initialize the stream */
if ((sp = malloc((u_int)sizeof(FTS))) == NULL)
if ((sp = malloc(sizeof(FTS))) == NULL)
return (NULL);
memset(sp, 0, sizeof(FTS));
sp->fts_compar = compar;
@ -547,6 +547,34 @@ fts_children(sp, instr)
return (sp->fts_child);
}
#ifndef fts_get_clientptr
#error "fts_get_clientptr not defined"
#endif
void *
(fts_get_clientptr)(FTS *sp)
{
return (fts_get_clientptr(sp));
}
#ifndef fts_get_stream
#error "fts_get_stream not defined"
#endif
FTS *
(fts_get_stream)(FTSENT *p)
{
return (fts_get_stream(p));
}
void
fts_set_clientptr(FTS *sp, void *clientptr)
{
sp->fts_clientptr = clientptr;
}
/*
* This is the tricky part -- do not casually change *anything* in here. The
* idea is to build the linked list of entries that are used by fts_children
@ -907,6 +935,21 @@ err: memset(sbp, 0, sizeof(struct stat));
return (FTS_DEFAULT);
}
/*
* The comparison function takes pointers to pointers to FTSENT structures.
* Qsort wants a comparison function that takes pointers to void.
* (Both with appropriate levels of const-poisoning, of course!)
* Use a trampoline function to deal with the difference.
*/
static int
fts_compar(const void *a, const void *b)
{
FTS *parent;
parent = (*(const FTSENT * const *)a)->fts_fts;
return (*parent->fts_compar)(a, b);
}
static FTSENT *
fts_sort(sp, head, nitems)
FTS *sp;
@ -932,7 +975,7 @@ fts_sort(sp, head, nitems)
}
for (ap = sp->fts_array, p = head; p; p = p->fts_link)
*ap++ = p;
qsort((void *)sp->fts_array, nitems, sizeof(FTSENT *), sp->fts_compar);
qsort(sp->fts_array, nitems, sizeof(FTSENT *), fts_compar);
for (head = *(ap = sp->fts_array); --nitems; ++ap)
ap[0]->fts_link = ap[1];
ap[0]->fts_link = NULL;
@ -948,26 +991,36 @@ fts_alloc(sp, name, namelen)
FTSENT *p;
size_t len;
struct ftsent_withstat {
FTSENT ent;
struct stat statbuf;
};
/*
* The file name is a variable length array and no stat structure is
* necessary if the user has set the nostat bit. Allocate the FTSENT
* structure, the file name and the stat structure in one chunk, but
* be careful that the stat structure is reasonably aligned. Since the
* fts_name field is declared to be of size 1, the fts_name pointer is
* namelen + 2 before the first possible address of the stat structure.
* be careful that the stat structure is reasonably aligned.
*/
len = sizeof(FTSENT) + namelen;
if (!ISSET(FTS_NOSTAT))
len += sizeof(struct stat) + ALIGNBYTES;
if (ISSET(FTS_NOSTAT))
len = sizeof(FTSENT) + namelen + 1;
else
len = sizeof(struct ftsent_withstat) + namelen + 1;
if ((p = malloc(len)) == NULL)
return (NULL);
/* Copy the name and guarantee NUL termination. */
memmove(p->fts_name, name, namelen);
p->fts_name[namelen] = '\0';
if (ISSET(FTS_NOSTAT)) {
p->fts_name = (char *)(p + 1);
p->fts_statp = NULL;
} else {
p->fts_name = (char *)((struct ftsent_withstat *)p + 1);
p->fts_statp = &((struct ftsent_withstat *)p)->statbuf;
}
if (!ISSET(FTS_NOSTAT))
p->fts_statp = (struct stat *)ALIGN(p->fts_name + namelen + 2);
/* Copy the name and guarantee NUL termination. */
memcpy(p->fts_name, name, namelen);
p->fts_name[namelen] = '\0';
p->fts_namelen = namelen;
p->fts_path = sp->fts_path;
p->fts_errno = 0;
@ -975,6 +1028,7 @@ fts_alloc(sp, name, namelen)
p->fts_instr = FTS_NOINSTR;
p->fts_number = 0;
p->fts_pointer = NULL;
p->fts_fts = sp;
return (p);
}

13
lib/libc/gen/fts-compat.h
View File

@ -47,7 +47,7 @@ typedef struct {
int fts_pathlen; /* sizeof(path) */
int fts_nitems; /* elements in the sort array */
int (*fts_compar) /* compare function */
(const struct _ftsent **, const struct _ftsent **);
(const struct _ftsent * const *, const struct _ftsent * const *);
#define FTS_COMFOLLOW 0x001 /* follow command line symlinks */
#define FTS_LOGICAL 0x002 /* logical walk */
@ -62,6 +62,7 @@ typedef struct {
#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 {
@ -113,7 +114,8 @@ typedef struct _ftsent {
u_short fts_instr; /* fts_set() instructions */
struct stat *fts_statp; /* stat(2) information */
char fts_name[1]; /* file name */
char *fts_name; /* file name */
FTS *fts_fts; /* back pointer to main FTS */
} FTSENT;
#include <sys/cdefs.h>
@ -121,10 +123,15 @@ typedef struct _ftsent {
__BEGIN_DECLS
FTSENT *fts_children(FTS *, int);
int fts_close(FTS *);
void *fts_get_clientptr(FTS *);
#define fts_get_clientptr(fts) ((fts)->fts_clientptr)
FTS *fts_get_stream(FTSENT *);
#define fts_get_stream(ftsent) ((ftsent)->fts_fts)
FTS *fts_open(char * const *, int,
int (*)(const FTSENT **, const FTSENT **));
int (*)(const FTSENT * const *, const FTSENT * const *));
FTSENT *fts_read(FTS *);
int fts_set(FTS *, FTSENT *, int);
void fts_set_clientptr(FTS *, void *);
__END_DECLS
#endif /* !_FTS_H_ */

45
lib/libc/gen/fts.3
View File

@ -32,7 +32,7 @@
.\" @(#)fts.3 8.5 (Berkeley) 4/16/94
.\" $FreeBSD$
.\"
.Dd April 16, 1994
.Dd September 15, 2002
.Dt FTS 3
.Os
.Sh NAME
@ -52,6 +52,12 @@
.Fn fts_children "FTS *ftsp" "int options"
.Ft int
.Fn fts_set "FTS *ftsp" "FTSENT *f" "int options"
.Ft void
.Fn fts_set_clientptr "FTS *ftsp" "void *clientdata"
.Ft void *
.Fn fts_get_clientptr "FTS *ftsp"
.Ft FTS *
.Fn fts_get_stream "FTSENT *f"
.Ft int
.Fn fts_close "FTS *ftsp"
.Sh DESCRIPTION
@ -105,6 +111,26 @@ and
.Dq Fa FTSENT No structure
are generally
interchangeable.
.Pp
The
.Fa FTS
structure contains space for a single pointer, which may be used to
store application data or per-hierarchy state.
The
.Fn fts_set_clientptr
and
.Fn fts_get_clientptr
functions may be used to set and retrieve this pointer.
This is likely to be useful only when accessed from the sort
comparison function, which can determine the original
.Fa FTS
stream of its arguments using the
.Fn fts_get_stream
function.
The two
.Li get
functions are also available as macros of the same name.
.Pp
The
.Fa FTSENT
structure contains at least the following fields, which are
@ -753,9 +779,18 @@ The options were invalid.
.Xr chdir 2 ,
.Xr stat 2 ,
.Xr qsort 3
.Sh STANDARDS
.Sh HISTORY
The
.Nm
utility is expected to be included in a future
.St -p1003.1-88
revision.
interface was first introduced in
.Bx 4.4 .
The
.Fn fts_get_clientptr ,
.Fn fts_get_stream ,
and
.Fn fts_set_clientptr
functions were introduced in
.Fx 5.0 ,
principally to provide for alternative interfaces to the
.Nm
functionality using different data structures.

82
lib/libc/gen/fts.c
View File

@ -81,7 +81,7 @@ FTS *
fts_open(argv, options, compar)
char * const *argv;
int options;
int (*compar)(const FTSENT **, const FTSENT **);
int (*compar)(const FTSENT * const *, const FTSENT * const *);
{
FTS *sp;
FTSENT *p, *root;
@ -96,7 +96,7 @@ fts_open(argv, options, compar)
}
/* Allocate/initialize the stream */
if ((sp = malloc((u_int)sizeof(FTS))) == NULL)
if ((sp = malloc(sizeof(FTS))) == NULL)
return (NULL);
memset(sp, 0, sizeof(FTS));
sp->fts_compar = compar;
@ -547,6 +547,34 @@ fts_children(sp, instr)
return (sp->fts_child);
}
#ifndef fts_get_clientptr
#error "fts_get_clientptr not defined"
#endif
void *
(fts_get_clientptr)(FTS *sp)
{
return (fts_get_clientptr(sp));
}
#ifndef fts_get_stream
#error "fts_get_stream not defined"
#endif
FTS *
(fts_get_stream)(FTSENT *p)
{
return (fts_get_stream(p));
}
void
fts_set_clientptr(FTS *sp, void *clientptr)
{
sp->fts_clientptr = clientptr;
}
/*
* This is the tricky part -- do not casually change *anything* in here. The
* idea is to build the linked list of entries that are used by fts_children
@ -907,6 +935,21 @@ err: memset(sbp, 0, sizeof(struct stat));
return (FTS_DEFAULT);
}
/*
* The comparison function takes pointers to pointers to FTSENT structures.
* Qsort wants a comparison function that takes pointers to void.
* (Both with appropriate levels of const-poisoning, of course!)
* Use a trampoline function to deal with the difference.
*/
static int
fts_compar(const void *a, const void *b)
{
FTS *parent;
parent = (*(const FTSENT * const *)a)->fts_fts;
return (*parent->fts_compar)(a, b);
}
static FTSENT *
fts_sort(sp, head, nitems)
FTS *sp;
@ -932,7 +975,7 @@ fts_sort(sp, head, nitems)
}
for (ap = sp->fts_array, p = head; p; p = p->fts_link)
*ap++ = p;
qsort((void *)sp->fts_array, nitems, sizeof(FTSENT *), sp->fts_compar);
qsort(sp->fts_array, nitems, sizeof(FTSENT *), fts_compar);
for (head = *(ap = sp->fts_array); --nitems; ++ap)
ap[0]->fts_link = ap[1];
ap[0]->fts_link = NULL;
@ -948,26 +991,36 @@ fts_alloc(sp, name, namelen)
FTSENT *p;
size_t len;
struct ftsent_withstat {
FTSENT ent;
struct stat statbuf;
};
/*
* The file name is a variable length array and no stat structure is
* necessary if the user has set the nostat bit. Allocate the FTSENT
* structure, the file name and the stat structure in one chunk, but
* be careful that the stat structure is reasonably aligned. Since the
* fts_name field is declared to be of size 1, the fts_name pointer is
* namelen + 2 before the first possible address of the stat structure.
* be careful that the stat structure is reasonably aligned.
*/
len = sizeof(FTSENT) + namelen;
if (!ISSET(FTS_NOSTAT))
len += sizeof(struct stat) + ALIGNBYTES;
if (ISSET(FTS_NOSTAT))
len = sizeof(FTSENT) + namelen + 1;
else
len = sizeof(struct ftsent_withstat) + namelen + 1;
if ((p = malloc(len)) == NULL)
return (NULL);
/* Copy the name and guarantee NUL termination. */
memmove(p->fts_name, name, namelen);
p->fts_name[namelen] = '\0';
if (ISSET(FTS_NOSTAT)) {
p->fts_name = (char *)(p + 1);
p->fts_statp = NULL;
} else {
p->fts_name = (char *)((struct ftsent_withstat *)p + 1);
p->fts_statp = &((struct ftsent_withstat *)p)->statbuf;
}
if (!ISSET(FTS_NOSTAT))
p->fts_statp = (struct stat *)ALIGN(p->fts_name + namelen + 2);
/* Copy the name and guarantee NUL termination. */
memcpy(p->fts_name, name, namelen);
p->fts_name[namelen] = '\0';
p->fts_namelen = namelen;
p->fts_path = sp->fts_path;
p->fts_errno = 0;
@ -975,6 +1028,7 @@ fts_alloc(sp, name, namelen)
p->fts_instr = FTS_NOINSTR;
p->fts_number = 0;
p->fts_pointer = NULL;
p->fts_fts = sp;
return (p);
}

4
usr.bin/find/find.c
View File

@ -56,7 +56,7 @@ __FBSDID("$FreeBSD$");
#include "find.h"
static int find_compare(const FTSENT **s1, const FTSENT **s2);
static int find_compare(const FTSENT * const *s1, const FTSENT * const *s2);
/*
* find_compare --
@ -66,7 +66,7 @@ static int find_compare(const FTSENT **s1, const FTSENT **s2);
*/
static int
find_compare(s1, s2)
const FTSENT **s1, **s2;
const FTSENT * const *s1, * const *s2;
{
return (strcoll((*s1)->fts_name, (*s2)->fts_name));

4
usr.sbin/ctm/ctm_dequeue/ctm_dequeue.c
View File

@ -53,7 +53,7 @@
#define DEFAULT_NUM 1 /* Default number of pieces mailed per run. */
int fts_sort(const FTSENT **, const FTSENT **);
int fts_sort(const FTSENT * const *, const FTSENT * const *);
int run_sendmail(int ifd);
int
@ -156,7 +156,7 @@ main(int argc, char **argv)
}
int
fts_sort(const FTSENT ** a, const FTSENT ** b)
fts_sort(const FTSENT * const * a, const FTSENT * const * b)
{
if ((*a)->fts_info != FTS_F)
return(0);

4
usr.sbin/mtree/create.c
View File

@ -80,7 +80,7 @@ static uid_t uid;
static mode_t mode;
static u_long flags = 0xffffffff;
static int dsort(const FTSENT **, const FTSENT **);
static int dsort(const FTSENT * const *, const FTSENT * const *);
static void output(int, int *, const char *, ...) __printflike(3, 4);
static int statd(FTS *, FTSENT *, uid_t *, gid_t *, mode_t *, u_long *);
static void statf(int, FTSENT *);
@ -398,7 +398,7 @@ statd(t, parent, puid, pgid, pmode, pflags)
static int
dsort(a, b)
const FTSENT **a, **b;
const FTSENT * const *a, * const *b;
{
if (S_ISDIR((*a)->fts_statp->st_mode)) {
if (!S_ISDIR((*b)->fts_statp->st_mode))

4
usr.sbin/pkg_install/lib/match.c
View File

@ -40,7 +40,7 @@ struct store {
static int rex_match(const char *, const char *);
struct store *storecreate(struct store *);
static int storeappend(struct store *, const char *);
static int fname_cmp(const FTSENT **, const FTSENT **);
static int fname_cmp(const FTSENT * const *, const FTSENT * const *);
/*
* Function to query names of installed packages.
@ -337,7 +337,7 @@ storeappend(struct store *store, const char *item)
}
static int
fname_cmp(const FTSENT **a, const FTSENT **b)
fname_cmp(const FTSENT * const *a, const FTSENT * const *b)
{
return strcmp((*a)->fts_name, (*b)->fts_name);
}