drgn/libdrgn/elfutils/libelf/common.h
Omar Sandoval 1cedca8ff4 Import elfutils
Based on:

c950e8a9 config: Fix spec file, add manpages and new GFDL license.

With the following patches:

configure: Add --disable-programs
configure: Add --disable-shared
configure: Fix -D_FORTIFY_SOURCE=2 check when CFLAGS contains -Wno-error
libcpu: compile i386_lex.c with -Wno-implicit-fallthrough

The plan is to stop relying on the distribution's version of elfutils
and instead ship our own. This gives us freedom to assume that we're
using the latest version and even ship our own patches (starting with a
few build system improvements). More details are in
scripts/update-elfutils.sh, which was used to generate this commit.
2019-09-05 01:04:33 -07:00

164 lines
4.2 KiB
C

/* Common definitions for handling files in memory or only on disk.
Copyright (C) 1998, 1999, 2000, 2002, 2005, 2008 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 1998.
This file is free software; you can redistribute it and/or modify
it under the terms of either
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at
your option) any later version
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at
your option) any later version
or both in parallel, as here.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see <http://www.gnu.org/licenses/>. */
#ifndef _COMMON_H
#define _COMMON_H 1
#include <ar.h>
#include <byteswap.h>
#include <endian.h>
#include <stdlib.h>
#include <string.h>
#include "libelfP.h"
static inline Elf_Kind
__attribute__ ((unused))
determine_kind (void *buf, size_t len)
{
/* First test for an archive. */
if (len >= SARMAG && memcmp (buf, ARMAG, SARMAG) == 0)
return ELF_K_AR;
/* Next try ELF files. */
if (len >= EI_NIDENT && memcmp (buf, ELFMAG, SELFMAG) == 0)
{
/* Could be an ELF file. */
int eclass = (int) ((unsigned char *) buf)[EI_CLASS];
int data = (int) ((unsigned char *) buf)[EI_DATA];
int version = (int) ((unsigned char *) buf)[EI_VERSION];
if (eclass > ELFCLASSNONE && eclass < ELFCLASSNUM
&& data > ELFDATANONE && data < ELFDATANUM
&& version == EV_CURRENT)
return ELF_K_ELF;
}
/* We do not know this file type. */
return ELF_K_NONE;
}
/* Allocate an Elf descriptor and fill in the generic information. */
static inline Elf *
__attribute__ ((unused))
allocate_elf (int fildes, void *map_address, int64_t offset, size_t maxsize,
Elf_Cmd cmd, Elf *parent, Elf_Kind kind, size_t extra)
{
Elf *result = (Elf *) calloc (1, sizeof (Elf) + extra);
if (result == NULL)
__libelf_seterrno (ELF_E_NOMEM);
else
{
result->kind = kind;
result->ref_count = 1;
result->cmd = cmd;
result->fildes = fildes;
result->start_offset = offset;
result->maximum_size = maxsize;
result->map_address = map_address;
result->parent = parent;
rwlock_init (result->lock);
}
return result;
}
/* Acquire lock for the descriptor and all children. */
static void
__attribute__ ((unused))
libelf_acquire_all (Elf *elf)
{
rwlock_wrlock (elf->lock);
if (elf->kind == ELF_K_AR)
{
Elf *child = elf->state.ar.children;
while (child != NULL)
{
if (child->ref_count != 0)
libelf_acquire_all (child);
child = child->next;
}
}
}
/* Release own lock and those of the children. */
static void
__attribute__ ((unused))
libelf_release_all (Elf *elf)
{
if (elf->kind == ELF_K_AR)
{
Elf *child = elf->state.ar.children;
while (child != NULL)
{
if (child->ref_count != 0)
libelf_release_all (child);
child = child->next;
}
}
rwlock_unlock (elf->lock);
}
/* Macro to convert endianess in place. It determines the function it
has to use itself. */
#define CONVERT(Var) \
(Var) = (sizeof (Var) == 1 \
? (unsigned char) (Var) \
: (sizeof (Var) == 2 \
? bswap_16 (Var) \
: (sizeof (Var) == 4 \
? bswap_32 (Var) \
: bswap_64 (Var))))
#define CONVERT_TO(Dst, Var) \
(Dst) = (sizeof (Var) == 1 \
? (unsigned char) (Var) \
: (sizeof (Var) == 2 \
? bswap_16 (Var) \
: (sizeof (Var) == 4 \
? bswap_32 (Var) \
: bswap_64 (Var))))
#if __BYTE_ORDER == __LITTLE_ENDIAN
# define MY_ELFDATA ELFDATA2LSB
#else
# define MY_ELFDATA ELFDATA2MSB
#endif
#endif /* common.h */