freebsd-skq/contrib/elftoolchain/libelf/elf_begin.c

92 lines
2.6 KiB
C

/*-
* Copyright (c) 2006,2008-2011 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 <libelf.h>
#include "_libelf.h"
ELFTC_VCSID("$Id: elf_begin.c 2364 2011-12-28 17:55:25Z jkoshy $");
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:
/*
* The ELF_C_WRITE command is required to ignore the
* descriptor passed in.
*/
a = NULL;
break;
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, 1);
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);
}