freebsd-skq/lib/csu/common/crtbrand.c
peter 81586929f3 Explicitly specify an alignment for abitag. Without it, gcc specifies a
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.
2003-10-17 15:43:13 +00:00

53 lines
1.9 KiB
C

/*-
* Copyright 2000 David E. O'Brien, John D. Polstra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#define ABI_VENDOR "FreeBSD"
#define ABI_SECTION ".note.ABI-tag"
#define ABI_NOTETYPE 1
/*
* Special ".note" entry specifying the ABI version. See
* http://www.netbsd.org/Documentation/kernel/elf-notes.html
* for more information.
*/
static const struct {
int32_t namesz;
int32_t descsz;
int32_t type;
char name[sizeof ABI_VENDOR];
int32_t desc;
} abitag __attribute__ ((section (ABI_SECTION), aligned(4))) __unused = {
sizeof ABI_VENDOR,
sizeof(int32_t),
ABI_NOTETYPE,
ABI_VENDOR,
__FreeBSD_version
};