minix/external/bsd/libelf/dist/elf_begin.c

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/* $NetBSD: elf_begin.c,v 1.7 2010/10/31 05:03:12 yamt Exp $ */
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/*-
* Copyright (c) 2006 Joseph Koshy
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* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif
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#include <sys/cdefs.h>
/* __FBSDID("$FreeBSD: src/lib/libelf/elf_begin.c,v 1.1.10.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */
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#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <ar.h>
#include <err.h>
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#include <errno.h>
#include <libelf.h>
#include <stdbool.h>
#include <stdlib.h>
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#include <unistd.h>
#include "_libelf.h"
static Elf *
_libelf_open_object(int fd, Elf_Cmd c)
{
Elf *e;
void *m;
void *p; /* malloc'ed pointer */
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struct stat sb;
size_t objsize;
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/*
* 'Raw' files are always mapped with 'PROT_READ'. At
* elf_update(3) time for files opened with ELF_C_RDWR the
* mapping is unmapped, file data is written to using write(2)
* and then the raw data is immediately mapped back in.
*/
if (fstat(fd, &sb) < 0) {
LIBELF_SET_ERROR(IO, errno);
return (NULL);
}
m = NULL;
p = NULL;
if (sb.st_size == 0) {
/*
* Might be a special device like /dev/ksyms. Try read(2)ing.
*/
goto doread;
}
objsize = (size_t) sb.st_size;
if ((m = mmap(NULL, objsize, PROT_READ, MAP_PRIVATE, fd,
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(off_t) 0)) == MAP_FAILED) {
size_t bufsize;
if (errno != EINVAL) {
LIBELF_SET_ERROR(IO, errno);
return (NULL);
}
doread:
/*
* Fall back to malloc+read.
*/
bufsize = 1024 * 1024;
while (/*CONSTCOND*/true) {
void *newp = realloc(p, bufsize);
ssize_t rsz;
if (newp == NULL) {
free(p);
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
p = newp;
rsz = pread(fd, p, bufsize, 0);
if (rsz == -1) {
free(p);
LIBELF_SET_ERROR(IO, errno);
return (NULL);
} else if ((size_t) rsz > bufsize) {
free(p);
LIBELF_SET_ERROR(IO, EIO); /* XXX */
return (NULL);
} else if ((size_t) rsz < bufsize) {
/*
* try to shrink the buffer.
*/
newp = realloc(p, (size_t) rsz);
if (newp != NULL) {
p = newp;
}
break;
}
bufsize *= 2;
}
m = p;
objsize = bufsize;
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}
if ((e = elf_memory(m, objsize)) == NULL) {
if (p != NULL) {
free(p);
} else {
(void) munmap(m, objsize);
}
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return (NULL);
}
if (p != NULL) {
e->e_flags |= LIBELF_F_MALLOC;
} else {
e->e_flags |= LIBELF_F_MMAP;
}
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e->e_fd = fd;
e->e_cmd = c;
if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) {
(void) elf_end(e);
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
return (e);
}
Elf *
elf_begin(int fd, Elf_Cmd c, Elf *a)
{
Elf *e;
e = NULL;
if (LIBELF_PRIVATE(version) == EV_NONE) {
LIBELF_SET_ERROR(SEQUENCE, 0);
return (NULL);
}
switch (c) {
case ELF_C_NULL:
return (NULL);
case ELF_C_WRITE:
if (a != NULL) { /* not allowed for ar(1) archives. */
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
/*
* Check writeability of `fd' immediately and fail if
* not writeable.
*/
if (ftruncate(fd, (off_t) 0) < 0) {
LIBELF_SET_ERROR(IO, errno);
return (NULL);
}
if ((e = _libelf_allocate_elf()) != NULL) {
_libelf_init_elf(e, ELF_K_ELF);
e->e_byteorder = _libelf_host_byteorder();
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e->e_fd = fd;
e->e_cmd = c;
}
return (e);
case ELF_C_RDWR:
if (a != NULL) { /* not allowed for ar(1) archives. */
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
/*FALLTHROUGH*/
case ELF_C_READ:
/*
* Descriptor `a' could be for a regular ELF file, or
* for an ar(1) archive.
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*/
if (a && (a->e_fd != fd || c != a->e_cmd)) {
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LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
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break;
default:
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
if (a == NULL)
e = _libelf_open_object(fd, c);
else if (a->e_kind == ELF_K_AR)
e = _libelf_ar_open_member(fd, c, a);
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else
(e = a)->e_activations++;
return (e);
}