On 12/15/22 14:17, Mark Wielaard wrote:
Hi Martin,
On Tue, 2022-11-29 at 13:05 +0100, Martin Liška wrote:
There's second version of the patch that fully support both
compression and decompression.
Changes from the v1:
- compression support added
- zstd detection is fixed
- new tests are added
- builds fine w/ and w/o the ZSTD library
What's currently missing and where I need a help:
1) When I build ./configure --without-zstd, I don't have
a reasonable error message (something similar to binutils's readelf:
readelf: Warning: section '.debug_str' has unsupported compress type:
2)
even though, __libelf_decompress returns NULL and __libelf_seterrno).
One can see a garbage in the console.
How to handle that properly?
Is there a particular way you are running eu-readelf? Is it with
generic -w or -a, or decoding a specific section type?
Hello.
$ LD_LIBRARY_PATH=./libelf ./src/readelf -w ~/Programming/testcases/a.out
where I get:
./src/readelf: cannot get debug context descriptor: No DWARF information found
DWARF section [37] '.debug_info' at offset 0x1ab2:
[Offset]
./src/readelf: cannot get next unit: no error
Call frame information section [13] '.eh_frame' at offset 0x4a8:
...
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E���Z
�O��Š�w��/#�!���7�6�#�I����*���굮R�v妗�/Z���O����Oի���E��z�����K��(��9���:{ѧ�zOa;̥�O�����+O�̰҆ˑ}��C��ۋ_�k9��
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Z�A!DJP%"�H�$i� Bc3�"
*** error, missing string terminator
So basically a garbage. And I don't know how to bail out properly?
2) How should I run my newly added tests conditionally if zstd
configuration support is enabled?
eu_ZIP will define an AM_CONDITIONAL for ZSTD (note this is different
from the HAVE_ZSTD, which is the am conditional added for having the
zstd program itself). You could use it in tests/Makefile.am as:
if ZSTD
TESTS += run-zstd-compress-test.sh
endif
If you had a separate test... Otherwise add some variable to
TESTS_ENVIRONMENT (and installed_TESTS_ENVIRONMENT) based on the Make
variable that is tested inside the shell script (somewhat like
USE_VALGRIND) maybe.
All right, I have a working version where I utilize an env. variable.
configure.ac | 8 +-
libelf/Makefile.am | 2 +-
libelf/elf_compress.c | 294 ++++++++++++++++++++++++++++++--
-----
libelf/elf_compress_gnu.c | 5 +-
libelf/libelfP.h | 4 +-
src/elfcompress.c | 144 ++++++++++--------
src/readelf.c | 18 ++-
tests/run-compress-test.sh | 24 +++
8 files changed, 373 insertions(+), 126 deletions(-)
diff --git a/configure.ac b/configure.ac
index 59be27ac..07cfa54b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -410,6 +410,11 @@ dnl Test for bzlib and xz/lzma/zstd, gives
BZLIB/LZMALIB/ZSTD .am
dnl conditional and config.h USE_BZLIB/USE_LZMALIB/USE_ZSTD #define.
save_LIBS="$LIBS"
LIBS=
+eu_ZIPLIB(zstd,ZSTD,zstd,ZSTD_decompress,[ZSTD (zst)])
+AS_IF([test "x$with_zstd" = xyes], [LIBZSTD="libzstd"], [LIBLZSTD=""])
+AC_SUBST([LIBZSTD])
+zstd_LIBS="$LIBS"
+AC_SUBST([zstd_LIBS])
eu_ZIPLIB(bzlib,BZLIB,bz2,BZ2_bzdopen,bzip2)
# We need this since bzip2 doesn't have a pkgconfig file.
BZ2_LIB="$LIBS"
@@ -417,9 +422,6 @@ AC_SUBST([BZ2_LIB])
eu_ZIPLIB(lzma,LZMA,lzma,lzma_auto_decoder,[LZMA (xz)])
AS_IF([test "x$with_lzma" = xyes], [LIBLZMA="liblzma"], [LIBLZMA=""])
AC_SUBST([LIBLZMA])
-eu_ZIPLIB(zstd,ZSTD,zstd,ZSTD_decompress,[ZSTD (zst)])
-AS_IF([test "x$with_zstd" = xyes], [LIBZSTD="libzstd"], [LIBLZSTD=""])
-AC_SUBST([LIBZSTD])
zip_LIBS="$LIBS"
LIBS="$save_LIBS"
AC_SUBST([zip_LIBS])
Doing AC_SUBST([zstd_LIBS]) seems correct. Why is the test moved
earlier?
You are testing for ZSTD_decompress, is that enough? Asking because I
see you are using ZSTD_compressStream2, which seems to requires libzstd
v1.4.0+.
In general how stable is the libzstd api?
It's hopefully stable, but yes, I should check for ZSTD_compressStream2 in
configure.ac.
I'm going to update that.
You'll also need to use the AC_SUBST for LIBZSTD in config/libelf.pc.in
now, as used in the libdw.pc.in:
Requires.private: zlib @LIBZSTD@
Oh, thanks.
Cheers,
Martin
diff --git a/libelf/Makefile.am b/libelf/Makefile.am
index 560ed45f..24c25cf8 100644
--- a/libelf/Makefile.am
+++ b/libelf/Makefile.am
@@ -106,7 +106,7 @@ libelf_pic_a_SOURCES =
am_libelf_pic_a_OBJECTS = $(libelf_a_SOURCES:.c=.os)
libelf_so_DEPS = ../lib/libeu.a
-libelf_so_LDLIBS = $(libelf_so_DEPS) -lz
+libelf_so_LDLIBS = $(libelf_so_DEPS) -lz $(zstd_LIBS)
if USE_LOCKS
libelf_so_LDLIBS += -lpthread
endif
OK.
Haven't read the actual code yet. I'll get back to that later today.
Cheers,
Mark
