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/*-
* Copyright (c) 2006,2008 Joseph Koshy
* 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.
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <ar.h>
#include <ctype.h>
#include <errno.h>
#include <libelf.h>
#include <unistd.h>
#include "_libelf.h"
LIBELF_VCSID("$Id$");
static Elf *
_libelf_open_object(int fd, Elf_Cmd c)
{
Elf *e;
void *m;
struct stat sb;
/*
* '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);
}
/*
* Restrict elf_begin(3) to regular files.
*
* In some operating systems, some special files can appear to
* contain ELF objects (for example, /dev/ksyms in NetBSD).
* If such files need to be processed using libelf,
* applications can use elf_memory(3) on an appropriately
* populated memory arena.
*/
if (!S_ISREG(sb.st_mode)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
m = NULL;
if ((m = mmap(NULL, (size_t) sb.st_size, PROT_READ, MAP_PRIVATE, fd,
(off_t) 0)) == MAP_FAILED) {
LIBELF_SET_ERROR(IO, errno);
return (NULL);
}
if ((e = elf_memory(m, (size_t) sb.st_size)) == NULL) {
(void) munmap(m, (size_t) sb.st_size);
return (NULL);
}
e->e_flags |= LIBELF_F_MMAP;
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_PRIVATE(byteorder);
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. If descriptor `a' was opened
* using a valid file descriptor, we need to check if
* the passed in `fd' value matches the original one.
*/
if (a &&
((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
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(a->e_fd, c, a);
else
(e = a)->e_activations++;
return (e);
}
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