In GNU ld and ld.lld, -dc is used with -r to allocate space to COMMON
symbols. It is presumably to work around legacy code which cannot
handle COMMON symbols in relocatable output. ld.lld may remove -dc or
make it a no-op for the 15.0.0 release.
As of 7420b323a0 crunch/crunchide does not require -dc, as the symbol
hiding technique no longer relied on making symbols local.
In addition -fno-common is now the default in Clang and GCC, so -dc
serves no purpose as the compiler does not generate COMMON symbols
anyway.
See https://maskray.me/blog/2022-02-06-all-about-common-symbols for more
detail on common symbols.
Reviewed by: emaste
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D34215
- One (1) constify
- One (1) argument is unused
- One (1) local shadows a global
- Various globals that should be static
Reviewed by: arichardson, imp
Differential Revision: https://reviews.freebsd.org/D31608
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
No functional change intended.
Some tools produce objects with a combined strtab and shstrtab.
These objects are not supported by crunchide since it rewrites the
symtab and strtab to "hide" symbols. This invalidates section header
offsets into a combined strtab/shstrtab.
In the future we could support these objects (by ensuring that we retain
unmodified section name strings in the output .strtab, and then rewriting
each section header's sh_name).
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.
Still need to add real targets under targets/ to build packages.
Differential Revision: D2796
Reviewed by: brooks imp
Most of the EM_* constants are available in all supported host branches,
but EM_AARCH64 was added relatively recently. Add it back to fix
building HEAD on 10.x.
Noticed by: adrian, jmallett
This avoids the need to build a target-specific crunchide for cross-
uilds.
Differential Revision: https://reviews.freebsd.org/D2314
Sponsored by: The FreeBSD Foundation
For 64-bit binaries the Elf_Ehdr e_shoff is at offset 40, not 44.
Instead of using an incorrect hardcoded offset, let the compiler
figure it out for us with offsetof().
Differential Revision: https://reviews.freebsd.org/D1543
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
1. 50+% of NO_PIE use is fixed by adding -fPIC to INTERNALLIB and other
build-only utility libraries.
2. Another 40% is fixed by generating _pic.a variants of various libraries.
3. Some of the NO_PIE use is a bit absurd as it is disabling PIE (and ASLR)
where it never would work anyhow, such as csu or loader. This suggests
there may be better ways of adding support to the tree. Many of these
cases can be fixed such that -fPIE will work but there is really no
reason to have it in those cases.
4. Some of the uses are working around hacks done to some Makefiles that are
really building libraries but have been using bsd.prog.mk because the code
is cleaner. Had they been using bsd.lib.mk then NO_PIE would not have
been needed.
We likely do want to enable PIE by default (opt-out) for non-tree consumers
(such as ports). For in-tree though we probably want to only enable PIE
(opt-in) for common attack targets such as remote service daemons and setuid
utilities. This is also a great performance compromise since ASLR is expected
to reduce performance. As such it does not make sense to enable it in all
utilities such as ls(1) that have little benefit to having it enabled.
Reported by: kib
This includes:
o All directories named *ia64*
o All files named *ia64*
o All ia64-specific code guarded by __ia64__
o All ia64-specific makefile logic
o Mention of ia64 in comments and documentation
This excludes:
o Everything under contrib/
o Everything under crypto/
o sys/xen/interface
o sys/sys/elf_common.h
Discussed at: BSDcan
This is currently an opt-in build flag. Once ASLR support is ready and stable
it should changed to opt-out and be enabled by default along with ASLR.
Each application Makefile uses opt-out to ensure that ASLR will be enabled by
default in new directories when the system is compiled with PIE/ASLR. [2]
Mark known build failures as NO_PIE for now.
The only known runtime failure was rtld.
[1] http://www.bsdcan.org/2014/schedule/events/452.en.html
Submitted by: Shawn Webb <lattera@gmail.com>
Discussed between: des@ and Shawn Webb [2]
The crunchide utility presumes the last 3 chunks of an ELF object
layout are section headers, symbol table, and then string table.
However, this is not specified in the ELF standards, and linkers
may generate different layouts when doing partial linking (-r).
This change is required to build FreeBSD with mclinker or the
gold linker.
PR: bin/174011
Submitted by: Pete Chou
Reviewed by: Cristoph Mallon
MFC after: 2 weeks
costs us another copy of the transform. Revert it.
# Maybe makefile.inc1 should set TARGET_CPUARCH for the cross-tools, but
# it doesn't now. That would solve problems in other places too.
Submitted by: jmallet@
I used the wrong type when setting st_name in the symbol table entry
struct. It's an Elf64_Word which is defined as an unsigned 32 bit int
on both 32 and 64 bit platforms.
To make things sensible, define some new macros to use as "word" macros
and use those, rather than simply using the explicit 32 bit macros.
The older symbol hiding method breaks for MIPS. This implements
symbol hiding through renaming to a symbol name which is highly
unlikely to clash.
The NetBSD code didn't use byte-swapping macros for endian-awareness;
so it didn't work when cross-compiling a MIPS world on i386/amd64.
This patch includes those (as best as I could figure what they
should be) and has been tested to generate valid MIPS crunch
binaries both cross- and native- compiled.
