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[Bug general/23370] run-next-cfi-self.sh doesn't handle compressed ELF sections
- From: "mark at klomp dot org" <sourceware-bugzilla at sourceware dot org>
- To: elfutils-devel at sourceware dot org
- Date: Thu, 05 Jul 2018 14:20:57 +0000
- Subject: [Bug general/23370] run-next-cfi-self.sh doesn't handle compressed ELF sections
- Auto-submitted: auto-generated
- References: <bug-23370-10460@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=23370
Mark Wielaard <mark at klomp dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mark at klomp dot org
Summary|run-next-cfi-self.sh fails |run-next-cfi-self.sh
|on armv7l |doesn't handle compressed
| |ELF sections
--- Comment #1 from Mark Wielaard <mark at klomp dot org> ---
Although relocations in ET_REL files could be an issue, they aren't actually
for this test, because the relocations that are there are against the addresses
inside to .debug_frame section, and we don't care what they are in this test
case.
[We do really need some easier way to apply simple relocations when dealing
with ET_REL files (currently you need to create a Dwfl, which is a bit overkill
in this case).]
The real issue in this case is that the toolchain that created this test file
(size.o) used ELF debug section compression:
[35] .debug_frame PROGBITS 00000000 0057e4 0000c5 0 C 0 0
4
[ELF ZLIB (1) 000154 4]
(Oddly enough it seems it only does this for ET_REL files and the linker again
decompresses again when creating the ET_EXEC/DYN files. Which seems horribly
inefficient.)
So the real fix is to just uncompress the section in the test:
diff --git a/tests/next_cfi.c b/tests/next_cfi.c
index b923744..ae324c4 100644
--- a/tests/next_cfi.c
+++ b/tests/next_cfi.c
@@ -33,7 +33,7 @@
#include <unistd.h>
void
-handle_section (const unsigned char e_ident[],
+handle_section (char *name, const unsigned char e_ident[],
Elf_Scn *scn, const bool is_eh)
{
if (is_eh)
@@ -41,6 +41,24 @@ handle_section (const unsigned char e_ident[],
else
printf (".debug_frame\n");
+ GElf_Shdr mem;
+ GElf_Shdr *shdr = gelf_getshdr (scn, &mem);
+ if (shdr == NULL)
+ error (EXIT_FAILURE, 0, "Couldn't get section header: %s",
+ elf_errmsg (-1));
+ if ((shdr->sh_flags & SHF_COMPRESSED) != 0)
+ {
+ if (elf_compress (scn, 0, 0) < 0)
+ error (EXIT_FAILURE, 0, "Couldn't decompress section: %s",
+ elf_errmsg (-1));
+ }
+ else if (name[0] == '.' && name[1] == 'z')
+ {
+ if (elf_compress_gnu (scn, 0, 0) < 0)
+ error (EXIT_FAILURE, 0, "Couldn't decompress section: %s",
+ elf_errmsg (-1));
+ }
+
Elf_Data *data = elf_getdata (scn, NULL);
if (data == NULL || data->d_buf == NULL)
error (EXIT_FAILURE, 0, "no section data");
@@ -117,9 +135,10 @@ main (int argc, char *argv[])
if (name != NULL && shdr.sh_type == SHT_PROGBITS)
{
if (strcmp (name, ".eh_frame") == 0)
- handle_section (ident, scn, true);
- if (strcmp (name, ".debug_frame") == 0)
- handle_section (ident, scn, false);
+ handle_section (name, ident, scn, true);
+ if (strcmp (name, ".debug_frame") == 0
+ || strcmp (name, ".zdebug_frame") == 0)
+ handle_section (name, ident, scn, false);
}
}
}
--
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