svn commit: r308264 - in head: include lib/libc/gen
Ed Schouten
ed at FreeBSD.org
Thu Nov 3 20:21:36 UTC 2016
Author: ed
Date: Thu Nov 3 20:21:34 2016
New Revision: 308264
URL: https://svnweb.freebsd.org/changeset/base/308264
Log:
Replace basename(3) by a thread-safe implementation.
Now that the changes to the dirname(3) function had some time to settle,
let's go ahead and use the same approach for replacing basename(3) by a
simple implementation that modifies the input string, thereby making it
thread-safe and guaranteed to succeed.
Unlike dirname(3), this function already had a thread-safe variant
basename_r(3). This function had its own set of problems, like having an
upper bound on the pathname length. Keep this function around for
compatibility, but remove most references from the man page. Make the
man page more similar to that of dirname(3).
As the basename_r(3) function is only provided by FreeBSD (and Bionic),
depending on its use is even more implementation defined than assuming
that basename(3) is thread-safe.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D8382
Added:
head/lib/libc/gen/basename_compat.c
- copied, changed from r306522, head/lib/libc/gen/basename.c
Modified:
head/include/libgen.h
head/lib/libc/gen/Makefile.inc
head/lib/libc/gen/Symbol.map
head/lib/libc/gen/basename.3
head/lib/libc/gen/basename.c
Modified: head/include/libgen.h
==============================================================================
--- head/include/libgen.h Thu Nov 3 19:58:12 2016 (r308263)
+++ head/include/libgen.h Thu Nov 3 20:21:34 2016 (r308264)
@@ -40,21 +40,24 @@ char *dirname(char *);
__END_DECLS
/*
- * In FreeBSD 12, the prototype of dirname() was modified to comply to
- * POSIX. This function may now modify its input. Unfortunately, our
- * copy of xinstall(8) shipped with previous versions of FreeBSD is
- * built using the host headers and libc during the bootstrapping phase
- * and depends on the old behavior.
+ * In FreeBSD 12, the prototypes of basename() and dirname() were
+ * modified to comply to POSIX. These functions may now modify their
+ * input. Unfortunately, our copy of xinstall(8) shipped with previous
+ * versions of FreeBSD is built using the host headers and libc during
+ * the bootstrapping phase and depends on the old behavior.
*
- * Apply a workaround where we explicitly link against dirname at FBSD_1.0
- * in case this function is called on constant strings, instead of
- * making the program crash at runtime.
+ * Apply a workaround where we explicitly link against basename at FBSD_1.0
+ * and dirname at FBSD_1.0 in case these functions are called on constant
+ * strings, instead of making the program crash at runtime.
*/
#if defined(__generic) && !defined(__cplusplus)
__BEGIN_DECLS
+char *__old_basename(char *);
char *__old_dirname(char *);
__END_DECLS
+__sym_compat(basename, __old_basename, FBSD_1.0);
__sym_compat(dirname, __old_dirname, FBSD_1.0);
+#define basename(x) __generic(x, const char *, __old_basename, basename)(x)
#define dirname(x) __generic(x, const char *, __old_dirname, dirname)(x)
#endif
Modified: head/lib/libc/gen/Makefile.inc
==============================================================================
--- head/lib/libc/gen/Makefile.inc Thu Nov 3 19:58:12 2016 (r308263)
+++ head/lib/libc/gen/Makefile.inc Thu Nov 3 20:21:34 2016 (r308264)
@@ -17,6 +17,7 @@ SRCS+= __getosreldate.c \
assert.c \
auxv.c \
basename.c \
+ basename_compat.c \
cap_sandboxed.c \
check_utility_compat.c \
clock.c \
Modified: head/lib/libc/gen/Symbol.map
==============================================================================
--- head/lib/libc/gen/Symbol.map Thu Nov 3 19:58:12 2016 (r308263)
+++ head/lib/libc/gen/Symbol.map Thu Nov 3 20:21:34 2016 (r308264)
@@ -68,7 +68,6 @@ FBSD_1.0 {
arc4random_addrandom;
arc4random_stir;
__assert;
- basename;
check_utility_compat;
clock;
closedir;
@@ -414,6 +413,7 @@ FBSD_1.4 {
};
FBSD_1.5 {
+ basename;
dirname;
};
Modified: head/lib/libc/gen/basename.3
==============================================================================
--- head/lib/libc/gen/basename.3 Thu Nov 3 19:58:12 2016 (r308263)
+++ head/lib/libc/gen/basename.3 Thu Nov 3 20:21:34 2016 (r308264)
@@ -16,7 +16,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd July 29, 2016
+.Dd October 29, 2016
.Dt BASENAME 3
.Os
.Sh NAME
@@ -26,8 +26,6 @@
.In libgen.h
.Ft char *
.Fn basename "char *path"
-.Ft char *
-.Fn basename_r "const char *path" "char *bname"
.Sh DESCRIPTION
The
.Fn basename
@@ -36,6 +34,7 @@ function returns the last component from
deleting any trailing
.Sq \&/
characters.
+.Sh RETURN VALUES
If
.Fa path
consists entirely of
@@ -48,48 +47,19 @@ If
is a null pointer or the empty string, a pointer to the string
.Qq \&.
is returned.
-.Pp
-The
-.Fn basename_r
-variation accepts a buffer of at least
-.Dv MAXPATHLEN
-bytes in which to store the resulting component.
+Otherwise,
+it returns a pointer to the last component of
+.Fa path .
.Sh IMPLEMENTATION NOTES
-The
-.Fn basename
-function
-returns a pointer to internal storage space allocated on the first call
-that will be overwritten
-by subsequent calls.
-.Pp
-Other vendor implementations of
+This implementation of
.Fn basename
-may store their result in the input buffer,
-making it safe to use in multithreaded applications.
-Future versions of
-.Fx
-will follow this approach as well.
-.Fn basename_r
-will then become obsolete.
-.Sh RETURN VALUES
-On successful completion,
-.Fn basename
-and
-.Fn basename_r
-return pointers to the last component of
-.Fa path .
-.Pp
-If they fail, a null pointer is returned and the global variable
-.Va errno
-is set to indicate the error.
-.Sh ERRORS
-The following error codes may be set in
-.Va errno :
-.Bl -tag -width Er
-.It Bq Er ENAMETOOLONG
-The path component to be returned was larger than
-.Dv MAXPATHLEN .
-.El
+uses the buffer provided by the caller to store the resulting pathname
+component.
+Other vendor implementations may return a pointer to internal storage
+space instead.
+The advantage of the former approach is that it ensures thread-safety,
+while also placing no upper limit on the supported length of the
+pathname.
.Sh SEE ALSO
.Xr basename 1 ,
.Xr dirname 1 ,
@@ -106,16 +76,13 @@ function first appeared in
.Ox 2.2
and
.Fx 4.2 .
-.Sh AUTHORS
-.An Todd C. Miller
-.Sh CAVEATS
-.Fn basename
-returns a pointer to internal static storage space that will be overwritten
-by subsequent calls.
.Pp
-Other vendor implementations of
-.Fn basename
-may modify the contents of the string passed to
-.Fn basename ;
-this should be taken into account when writing code which calls this function
-if portability is desired.
+In
+.Fx 12.0 ,
+this function was reimplemented to store its result in the provided
+input buffer.
+There is no longer any need to use the
+.Fn basename_r
+function.
+.Sh AUTHORS
+.An Nuxi, the Netherlands
Modified: head/lib/libc/gen/basename.c
==============================================================================
--- head/lib/libc/gen/basename.c Thu Nov 3 19:58:12 2016 (r308263)
+++ head/lib/libc/gen/basename.c Thu Nov 3 20:21:34 2016 (r308264)
@@ -1,79 +1,54 @@
-/* $OpenBSD: basename.c,v 1.14 2005/08/08 08:05:33 espie Exp $ */
-
-/*
- * Copyright (c) 1997, 2004 Todd C. Miller <Todd.Miller at courtesan.com>
+/*-
+ * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
*
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
+ * 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.
*
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
-#include <errno.h>
#include <libgen.h>
-#include <stdlib.h>
#include <string.h>
-#include <sys/param.h>
-
-char *
-basename_r(const char *path, char *bname)
-{
- const char *endp, *startp;
- size_t len;
-
- /* Empty or NULL string gets treated as "." */
- if (path == NULL || *path == '\0') {
- bname[0] = '.';
- bname[1] = '\0';
- return (bname);
- }
-
- /* Strip any trailing slashes */
- endp = path + strlen(path) - 1;
- while (endp > path && *endp == '/')
- endp--;
-
- /* All slashes becomes "/" */
- if (endp == path && *endp == '/') {
- bname[0] = '/';
- bname[1] = '\0';
- return (bname);
- }
-
- /* Find the start of the base */
- startp = endp;
- while (startp > path && *(startp - 1) != '/')
- startp--;
-
- len = endp - startp + 1;
- if (len >= MAXPATHLEN) {
- errno = ENAMETOOLONG;
- return (NULL);
- }
- memcpy(bname, startp, len);
- bname[len] = '\0';
- return (bname);
-}
char *
-basename(char *path)
+(basename)(char *path)
{
- static char *bname = NULL;
+ char *ptr;
- if (bname == NULL) {
- bname = (char *)malloc(MAXPATHLEN);
- if (bname == NULL)
- return (NULL);
- }
- return (basename_r(path, bname));
+ /*
+ * If path is a null pointer or points to an empty string,
+ * basename() shall return a pointer to the string ".".
+ */
+ if (path == NULL || *path == '\0')
+ return (__DECONST(char *, "."));
+
+ /* Find end of last pathname component and null terminate it. */
+ ptr = path + strlen(path);
+ while (ptr > path + 1 && *(ptr - 1) == '/')
+ --ptr;
+ *ptr-- = '\0';
+
+ /* Find beginning of last pathname component. */
+ while (ptr > path && *(ptr - 1) != '/')
+ --ptr;
+ return (ptr);
}
Copied and modified: head/lib/libc/gen/basename_compat.c (from r306522, head/lib/libc/gen/basename.c)
==============================================================================
--- head/lib/libc/gen/basename.c Fri Sep 30 19:21:02 2016 (r306522, copy source)
+++ head/lib/libc/gen/basename_compat.c Thu Nov 3 20:21:34 2016 (r308264)
@@ -66,7 +66,7 @@ basename_r(const char *path, char *bname
}
char *
-basename(char *path)
+__freebsd11_basename(char *path)
{
static char *bname = NULL;
@@ -77,3 +77,5 @@ basename(char *path)
}
return (basename_r(path, bname));
}
+
+__sym_compat(basename, __freebsd11_basename, FBSD_1.0);
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