[ was: Re: [PATCH 1/2][libbacktrace] Handle realloc returning NULL if size ==
0 ]
On Thu, Nov 22, 2018 at 06:16:20PM +0000, Joseph Myers wrote:
> On Thu, 22 Nov 2018, Tom de Vries wrote:
>
> > Hi,
> >
> > If realloc is called with size 0, realloc can return NULL.
>
> Note that, as of C17, realloc with size 0 is marked as an obsolescent
> feature (because of inconsistencies between implementations regarding
> whether the old object is deallocated). So it would be advisable for code
> intended to be portable to avoid calling realloc with size 0 at all.
>
Updated patch to avoid realloc with size 0.
OK for trunk?
Thanks,
- Tom
[libbacktrace] Avoid realloc with size == 0 in backtrace_vector_release
As of C17, realloc with size 0 is marked as an obsolescent feature.
Fix this in backtrace_vector_release by using free instead.
Bootstrapped and reg-tested on x86_64.
2018-11-22 Tom de Vries <tdevr...@suse.de>
* alloc.c (backtrace_vector_release): Handle vec->size == 0 using free
instead of realloc.
* Makefile.am (check_PROGRAMS): Add unittest.
* Makefile.in: Regenerate.
* unittest.c: New file.
---
libbacktrace/Makefile.am | 4 +++
libbacktrace/Makefile.in | 25 ++++++++++---
libbacktrace/alloc.c | 13 ++++++-
libbacktrace/unittest.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 129 insertions(+), 5 deletions(-)
diff --git a/libbacktrace/Makefile.am b/libbacktrace/Makefile.am
index ee47daee415..4b28984c4e0 100644
--- a/libbacktrace/Makefile.am
+++ b/libbacktrace/Makefile.am
@@ -89,6 +89,10 @@ check_PROGRAMS =
TESTS = $(check_PROGRAMS)
if NATIVE
+unittest_SOURCES = unittest.c testlib.c
+unittest_LDADD = libbacktrace.la
+
+check_PROGRAMS += unittest
btest_SOURCES = btest.c testlib.c
btest_CFLAGS = $(AM_CFLAGS) -g -O
diff --git a/libbacktrace/Makefile.in b/libbacktrace/Makefile.in
index 2b984bc127e..c79b67636c9 100644
--- a/libbacktrace/Makefile.in
+++ b/libbacktrace/Makefile.in
@@ -124,7 +124,7 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2)
$(am__EXEEXT_3) \
$(am__EXEEXT_4) $(am__EXEEXT_5) $(am__EXEEXT_6) \
$(am__EXEEXT_7) $(am__EXEEXT_8) $(am__EXEEXT_9) \
$(am__EXEEXT_10) $(am__EXEEXT_11) $(am__EXEEXT_12)
-@NATIVE_TRUE@am__append_1 = btest
+@NATIVE_TRUE@am__append_1 = unittest btest
@HAVE_MMAP_TRUE@@NATIVE_TRUE@am__append_2 = btest_with_alloc
@NATIVE_TRUE@am__append_3 = stest
@HAVE_MMAP_TRUE@@NATIVE_TRUE@am__append_4 = stest_with_alloc
@@ -170,7 +170,7 @@ AM_V_lt = $(am__v_lt_@AM_V@)
am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
am__v_lt_0 = --silent
am__v_lt_1 =
-@NATIVE_TRUE@am__EXEEXT_1 = btest$(EXEEXT)
+@NATIVE_TRUE@am__EXEEXT_1 = unittest$(EXEEXT) btest$(EXEEXT)
@HAVE_MMAP_TRUE@@NATIVE_TRUE@am__EXEEXT_2 = btest_with_alloc$(EXEEXT)
@NATIVE_TRUE@am__EXEEXT_3 = stest$(EXEEXT)
@HAVE_MMAP_TRUE@@NATIVE_TRUE@am__EXEEXT_4 = stest_with_alloc$(EXEEXT)
@@ -275,6 +275,10 @@ ttest_with_alloc_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC \
$(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=link $(CCLD) \
$(ttest_with_alloc_CFLAGS) $(CFLAGS) $(AM_LDFLAGS) $(LDFLAGS) \
-o $@
+@NATIVE_TRUE@am_unittest_OBJECTS = unittest.$(OBJEXT) \
+@NATIVE_TRUE@ testlib.$(OBJEXT)
+unittest_OBJECTS = $(am_unittest_OBJECTS)
+@NATIVE_TRUE@unittest_DEPENDENCIES = libbacktrace.la
@NATIVE_TRUE@am_ztest_OBJECTS = ztest-ztest.$(OBJEXT) \
@NATIVE_TRUE@ ztest-testlib.$(OBJEXT)
ztest_OBJECTS = $(am_ztest_OBJECTS)
@@ -335,8 +339,8 @@ SOURCES = $(libbacktrace_la_SOURCES)
$(EXTRA_libbacktrace_la_SOURCES) \
$(ctestg_with_alloc_SOURCES) $(edtest_SOURCES) \
$(edtest_with_alloc_SOURCES) $(stest_SOURCES) \
$(stest_with_alloc_SOURCES) $(ttest_SOURCES) \
- $(ttest_with_alloc_SOURCES) $(ztest_SOURCES) \
- $(ztest_with_alloc_SOURCES)
+ $(ttest_with_alloc_SOURCES) $(unittest_SOURCES) \
+ $(ztest_SOURCES) $(ztest_with_alloc_SOURCES)
am__can_run_installinfo = \
case $$AM_UPDATE_INFO_DIR in \
n|no|NO) false;; \
@@ -745,6 +749,8 @@ libbacktrace_la_LIBADD = \
libbacktrace_la_DEPENDENCIES = $(libbacktrace_la_LIBADD)
TESTS = $(check_PROGRAMS) $(am__append_12)
+@NATIVE_TRUE@unittest_SOURCES = unittest.c testlib.c
+@NATIVE_TRUE@unittest_LDADD = libbacktrace.la
@NATIVE_TRUE@btest_SOURCES = btest.c testlib.c
@NATIVE_TRUE@btest_CFLAGS = $(AM_CFLAGS) -g -O
@NATIVE_TRUE@btest_LDADD = libbacktrace.la
@@ -941,6 +947,10 @@ ttest_with_alloc$(EXEEXT): $(ttest_with_alloc_OBJECTS)
$(ttest_with_alloc_DEPEND
@rm -f ttest_with_alloc$(EXEEXT)
$(AM_V_CCLD)$(ttest_with_alloc_LINK) $(ttest_with_alloc_OBJECTS)
$(ttest_with_alloc_LDADD) $(LIBS)
+unittest$(EXEEXT): $(unittest_OBJECTS) $(unittest_DEPENDENCIES)
$(EXTRA_unittest_DEPENDENCIES)
+ @rm -f unittest$(EXEEXT)
+ $(AM_V_CCLD)$(LINK) $(unittest_OBJECTS) $(unittest_LDADD) $(LIBS)
+
ztest$(EXEEXT): $(ztest_OBJECTS) $(ztest_DEPENDENCIES)
$(EXTRA_ztest_DEPENDENCIES)
@rm -f ztest$(EXEEXT)
$(AM_V_CCLD)$(ztest_LINK) $(ztest_OBJECTS) $(ztest_LDADD) $(LIBS)
@@ -1293,6 +1303,13 @@ recheck: all $(check_PROGRAMS)
am__force_recheck=am--force-recheck \
TEST_LOGS="$$log_list"; \
exit $$?
+unittest.log: unittest$(EXEEXT)
+ @p='unittest$(EXEEXT)'; \
+ b='unittest'; \
+ $(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+ --log-file $$b.log --trs-file $$b.trs \
+ $(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS)
-- $(LOG_COMPILE) \
+ "$$tst" $(AM_TESTS_FD_REDIRECT)
btest.log: btest$(EXEEXT)
@p='btest$(EXEEXT)'; \
b='btest'; \
diff --git a/libbacktrace/alloc.c b/libbacktrace/alloc.c
index 7070afbf2aa..522b59dd59f 100644
--- a/libbacktrace/alloc.c
+++ b/libbacktrace/alloc.c
@@ -145,12 +145,23 @@ backtrace_vector_release (struct backtrace_state *state
ATTRIBUTE_UNUSED,
backtrace_error_callback error_callback,
void *data)
{
+ vec->alc = 0;
+
+ if (vec->size == 0)
+ {
+ /* As of C17, realloc with size 0 is marked as an obsolescent feature,
use
+ free instead. */
+ free (vec->base);
+ vec->base = NULL;
+ return 1;
+ }
+
vec->base = realloc (vec->base, vec->size);
if (vec->base == NULL)
{
error_callback (data, "realloc", errno);
return 0;
}
- vec->alc = 0;
+
return 1;
}
diff --git a/libbacktrace/unittest.c b/libbacktrace/unittest.c
new file mode 100644
index 00000000000..576aa080935
--- /dev/null
+++ b/libbacktrace/unittest.c
@@ -0,0 +1,92 @@
+/* unittest.c -- Test for libbacktrace library
+ Copyright (C) 2018 Free Software Foundation, Inc.
+
+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) The name of the author may not be used to
+ endorse or promote products derived from this software without
+ specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "filenames.h"
+
+#include "backtrace.h"
+#include "backtrace-supported.h"
+
+#include "testlib.h"
+
+#include "internal.h"
+
+static unsigned count;
+
+static void
+error_callback (void *vdata ATTRIBUTE_UNUSED, const char *msg ATTRIBUTE_UNUSED,
+ int errnum ATTRIBUTE_UNUSED)
+{
+ ++count;
+}
+
+static int
+test1 (void)
+{
+ int res;
+ int failed;
+
+ struct backtrace_vector vec;
+
+ memset (&vec, 0, sizeof vec);
+
+ backtrace_vector_grow (state, 100, error_callback, NULL, &vec);
+ vec.alc += vec.size;
+ vec.size = 0;
+
+ count = 0;
+ res = backtrace_vector_release (state, &vec, error_callback, NULL);
+ failed = res != 1 || count != 0;
+
+ printf ("%s: unittest backtrace_vector_release size == 0\n",
+ failed ? "FAIL": "PASS");
+
+ if (failed)
+ ++failures;
+
+ return failures;
+}
+
+int
+main (int argc ATTRIBUTE_UNUSED, char **argv)
+{
+ state = backtrace_create_state (argv[0], BACKTRACE_SUPPORTS_THREADS,
+ error_callback_create, NULL);
+
+ test1 ();
+
+ exit (failures ? EXIT_FAILURE : EXIT_SUCCESS);
+}
