Work around test breakages caused by custom regex engine used in
libasan, when address sanitizer is used with more recent versions
of gcc and clang.
* jk/asan-build-fix:
Makefile: use compat regex with SANITIZE=address
Recent versions of the gcc and clang Address Sanitizer produce test
failures related to regexec(). This triggers with gcc-10 and clang-8
(but not gcc-9 nor clang-7). Running:
make CC=gcc-10 SANITIZE=address test
results in failures in t4018, t3206, and t4062.
The cause seems to be that when built with ASan, we use a different
version of regexec() than normal. And this version doesn't understand
the REG_STARTEND flag. Here's my evidence supporting that.
The failure in t4062 is an ASan warning:
expecting success of 4062.2 '-G matches':
git diff --name-only -G "^(0{64}){64}$" HEAD^ >out &&
test 4096-zeroes.txt = "$(cat out)"
=================================================================
==672994==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7fa76f672000 at pc 0x7fa7726f75b6 bp 0x7ffe41bdda70 sp 0x7ffe41bdd220
READ of size 4097 at 0x7fa76f672000 thread T0
#0 0x7fa7726f75b5 (/lib/x86_64-linux-gnu/libasan.so.6+0x4f5b5)
#1 0x562ae0c9c40e in regexec_buf /home/peff/compile/git/git-compat-util.h:1117
#2 0x562ae0c9c40e in diff_grep /home/peff/compile/git/diffcore-pickaxe.c:52
#3 0x562ae0c9cc28 in pickaxe_match /home/peff/compile/git/diffcore-pickaxe.c:166
[...]
In this case we're looking in a buffer which was mmap'd via
reuse_worktree_file(), and whose size is 4096 bytes. But libasan's
regex tries to look at byte 4097 anyway! If we tweak Git like this:
diff --git a/diff.c b/diff.c
index 8e2914c031..cfae60c120 100644
--- a/diff.c
+++ b/diff.c
@@ -3880,7 +3880,7 @@ static int reuse_worktree_file(struct index_state *istate,
*/
if (ce_uptodate(ce) ||
(!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
- return 1;
+ return 0;
return 0;
}
to use a regular buffer (with a trailing NUL) instead of an mmap, then
the complaint goes away.
The other failures are actually diff output with an incorrect funcname
header. If I instrument xdiff to show the funcname matching like so:
diff --git a/xdiff-interface.c b/xdiff-interface.c
index 8509f9ea22..f6c3dc1986 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -197,6 +197,7 @@ struct ff_regs {
struct ff_reg {
regex_t re;
int negate;
+ char *printable;
} *array;
};
@@ -218,7 +219,12 @@ static long ff_regexp(const char *line, long len,
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
- if (!regexec_buf(®->re, line, len, 2, pmatch, 0)) {
+ int ret = regexec_buf(®->re, line, len, 2, pmatch, 0);
+ warning("regexec %s:\n regex: %s\n buf: %.*s",
+ ret == 0 ? "matched" : "did not match",
+ reg->printable,
+ (int)len, line);
+ if (!ret) {
if (reg->negate)
return -1;
break;
@@ -264,6 +270,7 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
expression = value;
if (regcomp(®->re, expression, cflags))
die("Invalid regexp to look for hunk header: %s", expression);
+ reg->printable = xstrdup(expression);
free(buffer);
value = ep + 1;
}
then when compiling with ASan and gcc-10, running the diff from t4018.66
produces this:
$ git diff -U1 cpp-skip-access-specifiers
warning: regexec did not match:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: private:
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ private:
void DoSomething();
int ChangeMe;
};
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
That first regex should match (and is negated, so it should be telling
us _not_ to match "private:"). But it wouldn't if regexec() is looking
at the whole buffer, and not just the length-limited line we've fed to
regexec_buf(). So this is consistent again with REG_STARTEND being
ignored.
The correct output (compiling without ASan, or gcc-9 with Asan) looks
like this:
warning: regexec matched:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
[...more lines that we end up not using...]
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: class RIGHT : public Baseclass
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ class RIGHT : public Baseclass
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
So it really does seem like libasan's regex engine is ignoring
REG_STARTEND. We should be able to work around it by compiling with
NO_REGEX, which would use our local regexec(). But to make matters even
more interesting, this isn't enough by itself.
Because ASan has support from the compiler, it doesn't seem to intercept
our call to regexec() at the dynamic library level. It actually
recognizes when we are compiling a call to regexec() and replaces it
with ASan-specific code at that point. And unlike most of our other
compat code, where we might have git_mmap() or similar, the actual
symbol name in the compiled compat/regex code is regexec(). So just
compiling with NO_REGEX isn't enough; we still end up in libasan!
We can work around that by having the preprocessor replace regexec with
git_regexec (both in the callers and in the actual implementation), and
we truly end up with a call to our custom regex code, even when
compiling with ASan. That's probably a good thing to do anyway, as it
means anybody looking at the symbols later (e.g., in a debugger) would
have a better indication of which function is which. So we'll do the
same for the other common regex functions (even though just regexec() is
enough to fix this ASan problem).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We have several modules originally taken from some upstream source,
and which as far as I can tell we no longer update from the upstream
anymore. As such, I have not submitted these spelling fixes to any
external projects but just include them directly here.
Reported-by: Jens Schleusener <Jens.Schleusener@fossies.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The mailing address for the FSF has changed over the years. Rather than
updating the address across all files, refer readers to gnu.org, as the
GNU GPL documentation now suggests for license notices. The mailing
address is retained in the full license files (COPYING and LGPL-2.1).
The old address is still present in t/diff-lib/COPYING. This is
intentional, as the file is used in tests and the contents are not
expected to change.
Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We need to define -DGAWK -DNO_MBSUPPORT so that the gawk regex engine
will compile, and include stdio.h and stddef.h in regex.h. Gawk itself
includes these headers before it includes the regex.h header.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the regex engine in compat to use the gawk engine from the
gawk-devel module in gawk CVS. This engine supports the REG_STARTEND
flag, which was optionally available in Git since v1.7.2-rc0~77^2~1.
The source was grabbed from cvs.savannah.gnu.org:/sources/gawk, and
these are the upstream versions of the files being included:
regcomp.c 1.4
regex.h 1.3
regex.h 1.3
regex_internal.c 1.3
regex_internal.h 1.3
regexec.c 1.3
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The standard libc regex library on OSX does not support alternation
in POSIX Basic Regular Expression mode. This breaks the diff.funcname
functionality on OSX.
To fix this, we use the GNU regex library which is already present in
the compat/ diretory for the MinGW port. However, simply adding compat/
to the COMPAT_CFLAGS variable causes a conflict between the system
fnmatch.h and the one present in compat/. To remedy this, move the
regex and fnmatch functionality to their own subdirectories in compat/
so they can be included seperately.
Signed-off-by: Arjen Laarhoven <arjen@yaph.org>
Tested-by: Mike Ralphson <mike@abacus.co.uk> (AIX)
Tested-by: Johannes Sixt <johannes.sixt@telecom.at> (MinGW)
Signed-off-by: Junio C Hamano <gitster@pobox.com>
