Use the input file's .shstrtab size as the hint if it exists. This
gives a small performance improvement when processing files with
many sections.
Reviewed by: emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20544
The string's length is already known, so use memcpy() instead of
strcpy() to add it to the string table image.
Reviewed by: emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20760
- Add constants for OpenBSD wxneeded, bootdata and randomize to the
FreeBSD elf_common.h file. This is the file that gets used by the
elftoolchain library.
- Update readelf and elfdump utilities to decode these program headers
if they are encountered.
Note: FreeBSD has it's own version of elfdump(1), which will be updated
in a subsequent commit. I am adding it here anyway because this diff is
going to be submitted upstream.
Discussed with: emaste
Reviewed by: imp
MFC afer: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20548
M contrib/elftoolchain/elfdump/elfdump.c
M contrib/elftoolchain/readelf/readelf.c
M sys/sys/elf_common.h
This replaces some hand-rolled routines and is substantially faster
since libelftc uses a hash table for lookups and insertions, whereas
elfcopy would perform a linear scan of the table.
PR: 234949
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20473
When removing a section, we would loop over all sections looking for
a corresponding relocation section. With r348652 it is much faster
to just use elf_getscn().
PR: 234949
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20471
The tree is indexed by section number. This speeds up elf_getscn()
and its callers, which previously had to traverse a linked list. In
particular, since .shstrtab is often the last section in a file,
elf_strptr() would have to traverse the entire list.
PR: 234949
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20443
This is the common case when strip(1) is creating the output file.
The change provides a significant speedup when running on ELF files with
many sections.
PR: 234949
Reviewed by: emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20444
Summary:
Due to missing relocation support in libdwarf for powerpc64, handling of dwarf
info on unlinked objects was bogus.
Examining raw dwarf data on objects compiled on ppc64 with a modern compiler
(in-tree gcc tends to hide the issue, since it only rarely generates relocations
in .debug_info and uses DW_FORM_str instead of DW_FORM_strp for everything), you
will find that the dwarf data appears corrupt, with repeated references to the
compiler version where things like types and function names should appear.
This happens because the 0 offset of .debug_str contains the compiler version,
and without applying the relocations, *all* indirect strings in .dwarf_info will
end up pointing to it.
This corruption then propogates to the CTF data, as ctfconvert relies on
libdwarf to read the dwarf info, for every compiled object (when building a
kernel.)
However, if you examine the dwarf data on a compiled executable, it will appear
correct, because during final link the relocations get applied and baked in by
the linker.
Submitted by: Brandon Bergren
Reviewed By: emaste
Differential Revision: https://reviews.freebsd.org/D20367
Use an array instead of STAILQ, and sort at the end instead of while
adding new elements.
PR: 212539
Submitted by: Bora Özarslan <borako.ozarslan@gmail.com>
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
r345620 by kib@ fixed the rtld issue that caused a crash at startup
during resolution of libc's ifuncs with BIND_NOW.
PR: 233333
Sponsored by: The FreeBSD Foundation
Relative directories may appear in the line number program for a CPU if
files were included via a relative path, for instance with "-I.".
Previously, dwarf_srclines(3) and dwarf_srcfiles(3) would return the
relative path, so addr2line, for instance, would do the same. However,
we can get an absolute path by prepending the compilation directory, so
change libdwarf to do that to improve compatibility with GNU binutils
and since it is more useful in general.
Reviewed by: jhb
Discussed with: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19705
If we returning 32 bits value it's hard to distinguish if the returned value
is a valid one or if its an error (in case of EOF). For that reason separate
exit code of the function from the returned character.
Reported by: cem, se
Instead of depending on one stdin FILE structure and use freopen(3), pass to
the functions appropriate FILE structure.
Reviewed by: cem
Discussed with: emaste
Differential Revision: https://reviews.freebsd.org/D18037
Fewer lines of code and more maintainable.
Reviewed by: brooks, kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19053
Output format is compatible with GNU readelf's handling of unknown note
types (modulo a GNU char signedness bug); future changes will add type-
specific decoding.
Reviewed by: kib
MFC after: 1 week
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Highlights:
- Make sure that only TLS sections are sorted into TLS segment.
- Fixed multiple errors in "Section to Segment mapping".
- Man page updates
- ar improvements
- elfcopy: avoid filter_reloc uninitialized variable for rela
- elfcopy: avoid stripping relocations from static binaries
- readelf: avoid printing directory in front of absolute path
- readelf: add NT_FREEBSD_FEATURE_CTL FreeBSD note type
- test improvements
NOTES:
Some of these changes originated in FreeBSD and simply reduce diffs
between contrib and vendor.
ELF Tool Chain ar is not (currently) used in FreeBSD, and there are
improvements in both FreeBSD and ELF Tool Chain ar that are not in
the other.
Sponsored by: The FreeBSD Foundation
is that both file name and current directory is recorded, however
file name sometimes already contains absolute path. In which case
prefixing it with directory name results in an invalid pathname.
Only append directory name if the file name does not start with '/'.
This seems to DTRT.
Approved by: emaste
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D18290
This ELF note will be used to allow binaries to opt out of, or in to,
upcoming vulnerability mitigation and other features.
Committing the definition and readelf change separately to allow
independent MFC.
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Although _libelf_is_mips64el is only called in contexts where we've
already checked that e_class is ELFCLASS64 but this may change in the
future. Add a safety belt so that we don't access an invalid e_ehdr64
union member if it does.
Reported by: jkoshy (in review D17380)
In r339350 filter_reloc() was removed, to fix the case of stripping
statically linked binaries with relocations (which may come from ifunc
use, for example). As a side effect this changed the behaviour when
stripping object files - the output was broken both before and after
r339350, in different ways. Unfortunately GCC's build process relies
on the previous behaviour, so:
- Revert r339350, restoring filter_reloc().
- Fix an unitialized variable use (commited as r3638 in ELF Tool Chain).
- Change filter_reloc() to omit relocations referencing removed
symbols, while retaining relocations with no symbol reference.
- Retain the entire relocation section if it references the dynamic
symbol table (fix from kaiw in D17596).
PR: 232176
Reported by: antoine
Reviewed by: kaiw
MFC with: r339350
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17596
elfcopy contained logic to filter individual relocations in STRIP_ALL
mode. However, this is not valid; relocations emitted by the linker are
required, unless they apply to an entire section being removed (which is
handled by other logic in elfcopy).
Note that filter_reloc was also buggy: for RELA relocation sections it
operated on uninitialized rel.r_info resulting in invalid operation.
The logic most likely needs to be inverted: instead of removing
relocations because their associated symbols are being removed, we must
keep symbols referenced by relocations. That said, in practice we do
not encounter this code path today: objects being stripped are either
dynamically linked binaries which retain .dynsym, or static binaries
with no relocations.
Just remove filter_reloc. This fixes certain cases including statically
linked binaries containing ifuncs. Stripping binaries with relocations
referencing removed symbols was already broken, and after this change
may still be broken in a different way.
PR: 232176
Reviewed by: kaiw, kib, markj
Approved by: re (rgrimes)
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17519
libelf maintains two views of endianness: e_byteorder, and
e_ident[EI_DATA] in the ELF header itself. e_byteorder is not always
kept in sync, so use the ELF header endianness to test for mips64el.
PR: 231790
Bisected by: sbruno
Reviewed by: jhb
Approved by: re (kib)
MFC with: r338478
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17380
MIPS64 does not store the 'r_info' field of a relocation table entry as
a 64-bit value consisting of a 32-bit symbol index in the high 32 bits
and a 32-bit type in the low 32 bits as on other architectures. Instead,
the 64-bit 'r_info' field is really a 32-bit symbol index followed by four
individual byte type fields. For big-endian MIPS64, treating this as a
64-bit integer happens to be compatible with the layout expected by other
architectures (symbol index in upper 32-bits of resulting "native" 64-bit
integer). However, for little-endian MIPS64 the parsed 64-bit integer
contains the symbol index in the low 32 bits and the 4 individual byte
type fields in the upper 32-bits (but as if the upper 32-bits were
byte-swapped).
To cope, add two helper routines in gelf_getrel.c to translate between the
correct native 'r_info' value and the value obtained after the normal
byte-swap translation. Use these routines in gelf_getrel(), gelf_getrela(),
gelf_update_rel(), and gelf_update_rela(). This fixes 'readelf -r' on
little-endian MIPS64 objects which was previously decoding incorrect
relocations as well as 'objcopy: invalid symbox index' warnings from
objcopy when extracting debug symbols from kernel modules.
Even with this fixed, objcopy was still crashing when trying to extract
debug symbols from little-endian MIPS64 modules. The workaround in
gelf_*rel*() depends on the current ELF object having a valid ELF header
so that the 'e_machine' field can be compared against EM_MIPS. objcopy
was parsing the relocation entries to possibly rewrite the 'r_info' fields
in the update_relocs() function before writing the initial ELF header to
the destination object file. Move the initial write of the ELF header
earlier before copy_contents() so that update_relocs() uses the correct
symbol index values.
Note that this change should really go upstream. The binutils readelf
source has a similar hack for MIPS64EL though I implemented this version
from scratch using the MIPS64 ABI PDF as a reference.
Discussed with: jkoshy
Reviewed by: emaste, imp
Approved by: re (gjb, kib)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D15734
NT_GNU_PROPERTY_TYPE_0 in a .note.gnu.property section "contains a
program property note which describes special handling requirements
for linker and run-time loader." (from the System V Application Binary
Interface - Linux Extensions")
Intel CET uses two processor-specific program properties in
NT_GNU_PROPERTY_TYPE_0: GNU_PROPERTY_X86_FEATURE_1_IBT to indicate that
all executable sections are compatible with Indirect Branch Tracking,
and GNU_PROPERTY_X86_FEATURE_1_SHSTK to indicate that sections are
compatible with shadow stack.
A later change should add decoding of the individual properties.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
These issues (PR 218860 and PR 218861) are still undergoing additional
discussion in the upstream context and there may be additional changes
to come.
PR: 218860
Submitted by: Eric McCorkle
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D10486
