This note will be used to allow binaries to opt out of, or in to,
upcoming vulnerability mitigation and other features. It is not yet
connected but being added now to facilitate testing and ensure
compatibility with existing kernels and tools.
Reviewed by: brooks, jhb, kib, markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17438
This makes it easier to grep the source tree for these notes, and
ensures that they will remain in sync.
Reviewed by: kib
Approved by: re (gjb)
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17408
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified 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.
call preinit, init and fini arrays methods from crt1 for static binaries.
Mark new crt1 with FreeBSD-specific ELF note.
Move some common crt1 code into new MI file ignore_init.c, to reduce
duplication. Also, conservatively adjust nearby sources for style.
Reviewed by: kan
Tested by: andrew (arm), flo (sparc64)
MFC after: 3 weeks
generated from lib/csu/common/crtbrand.c (which ultimately ends up in
executables and shared libraries, via crt1.o, gcrt1.o or Scrt1.o).
For all arches except sparc, gcc emits the section directive for the
abitag struct in crtbrand.c with a PROGBITS type. However, newer
versions of binutils (after 2.16.90) require the section to be of NOTE
type, to guarantee that the .note.ABI-tag section correctly ends up in
the first page of the final executable.
Unfortunately, there is no clean way to tell gcc to use another section
type, so crtbrand.c (or the C files that include it) must be compiled in
multiple steps:
- Compile the .c file to a .s file.
- Edit the .s file to change the 'progbits' type to 'note', for the section
directive that defines the .note.ABI-tag section.
- Compile the .s file to an object file.
These steps are done in the invididual Makefiles for each applicable arch.
Reviewed by: kib
section alignnment of 16 bytes for amd64 and this breaks file(1).
Before:
./cp: ELF 64-bit LSB executable, AMD x86-64, version 1 (FreeBSD), for \
FreeBSD 127.7.9, statically linked, stripped
after: ^^^^^^^
./ls: ELF 64-bit LSB executable, AMD x86-64, version 1 (FreeBSD), for \
FreeBSD 5.0.1, dynamically linked (uses shared libs), stripped
The reason for this is that the NOTE sections are not contiguous
internally. If the note section has an alignment of 16, then anything
that looks for the data is supposed to round up the payload start to
the next multiple of the alignment. But FreeBSD/amd64 broke because the
structure is declared as a single structure, not a (header,payload) group,
where the payload had an explicit alignment roundup.
The alternative is to change things like file(1) to ignore the ELF payload
alignment rules for the PT_NOTE section only for FreeBSD.
when using the egcs and gcc-devel ports, along with GCC built from stock
public FSF sources. With out this change, FreeBSD will be removed from
the list of systems GCC 3.0 must be evaluated on before release. With
the effort some of us put into getting FreeBSD on this list, we should
not turn this effort into a waste, else we might not be worth fighting
for in the future. (note that Alpha and IA-64 versions of crt{i,n}.S
are needed)
* Switch from our own crt{begin,in} to those created from GCC's crtstuff.c.
This will allow us to switch to DWARF2 exceptions in the future, along with
staying in sync with any future GCC requirements.
* Break out our ELF branding bits into a seperate file. Currently this
is now included by our crt1.c files (since this functionality was part of
our native crtbegin.c). Later crtbrand.o will be merged in the creation
of crti.o.
