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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
*/
/* Copyright (c) 1988 AT&T */
/* All Rights Reserved */
#include <stdlib.h>
#include <errno.h>
#include <libelf.h>
#include "decl.h"
#include "msg.h"
/*
* Convert archive symbol table to memory format
*
* This takes a pointer to file's archive symbol table, alignment
* unconstrained. Returns null terminated vector of Elf_Arsym
* structures. Elf_Arsym uses size_t to represent offsets, which
* will be 32-bit in 32-bit versions, and 64-bits otherwise.
*
* There are two forms of archive symbol table, the original 32-bit
* form, and a 64-bit form originally found in IRIX64. The two formats
* differ only in the width of the integer word:
*
* # offsets 4/8-byte word
* offset[0...] 4/8-byte word each
* strings null-terminated, for offset[x]
*
* By default, the 64-bit form is only used when the archive exceeds
* the limits of 32-bits (4GB) in size. However, this is not required,
* and the ar -S option can be used to create a 64-bit symbol table in
* an archive that is under 4GB.
*
* Both 32 and 64-bit versions of libelf can read the 32-bit format
* without loss of information. Similarly, a 64-bit version of libelf
* will have no problem reading a 64-bit symbol table. This leaves the
* case where a 32-bit libelf reads a 64-bit symbol table, which requires
* some explanation. The offsets in a 64-bit symbol table will have zeros
* in the upper half of the words until the size of the archive exceeds 4GB.
* However, 32-bit libelf is unable to read any files larger than 2GB
* (see comments in update.c). As such, any archive that the 32-bit version
* of this code will encounter will be under 4GB in size. The upper 4
* bytes of each word will be zero, and can be safely ignored.
*/
/*
* Offsets in archive headers are written in MSB (large endian) order
* on all platforms, regardless of native byte order. These macros read
* 4 and 8 byte values from unaligned memory.
*
* note:
* - The get8() macro for 32-bit code can ignore the first 4 bytes of
* of the word, because they are known to be 0.
*
* - The inner most value in these macros is cast to an unsigned integer
* of the final width in order to prevent the C comilier from doing
* unwanted sign extension when the topmost bit of a byte is set.
*/
#define get4(p) (((((((uint32_t)p[0]<<8)+p[1])<<8)+p[2])<<8)+p[3])
#ifdef _LP64
#define get8(p) (((((((((((((((uint64_t)p[0]<<8)+p[1])<<8)+p[2])<<8)+ \
p[3])<<8)+p[4])<<8)+p[5])<<8)+p[6])<<8)+p[7])
#else
#define get8(p) (((((((uint64_t)p[4]<<8)+p[5])<<8)+p[6])<<8)+p[7])
#endif
static Elf_Void *
arsym(Byte *off, size_t sz, size_t *e, int is64)
{
char *endstr = (char *)off + sz;
register char *str;
Byte *endoff;
Elf_Void *oas;
size_t eltsize = is64 ? 8 : 4;
{
register size_t n;
if (is64) {
if (sz < 8 || (sz - 8) / 8 < (n = get8(off))) {
_elf_seterr(EFMT_ARSYMSZ, 0);
return (NULL);
}
} else {
if (sz < 4 || (sz - 4) / 4 < (n = get4(off))) {
_elf_seterr(EFMT_ARSYMSZ, 0);
return (NULL);
}
}
off += eltsize;
endoff = off + n * eltsize;
/*
* If there are symbols in the symbol table, a
* string table must be present and NULL terminated.
*
* The format dictates that the string table must always be
* present, however in the case of an archive containing no
* symbols GNU ar will not create one. We are permissive for
* the sake of compatibility.
*/
if ((n > 0) && (((str = (char *)endoff) >= endstr) ||
(*(endstr - 1) != '\0'))) {
_elf_seterr(EFMT_ARSYM, 0);
return (NULL);
}
/*
* There is always at least one entry returned if a symtab
* exists since the table's last entry is an artificial one
* with a NULL as_name, but is included in the count.
*
* overflow can occur here, but not likely
*/
*e = n + 1;
if ((oas = calloc(n + 1, sizeof (Elf_Arsym))) == NULL) {
_elf_seterr(EMEM_ARSYM, errno);
return (NULL);
}
}
{
register Elf_Arsym *as = (Elf_Arsym *)oas;
while (off < endoff) {
if (str >= endstr) {
_elf_seterr(EFMT_ARSYMSTR, 0);
free(oas);
return (NULL);
}
if (is64)
as->as_off = get8(off);
else
as->as_off = get4(off);
as->as_name = str;
as->as_hash = elf_hash(str);
++as;
off += eltsize;
while (*str++ != '\0')
/* LINTED */
;
}
as->as_name = NULL;
as->as_off = 0;
as->as_hash = ~(unsigned long)0L;
}
return (oas);
}
Elf_Arsym *
elf_getarsym(Elf *elf, size_t *ptr)
{
Byte *as;
size_t sz;
Elf_Arsym *rc;
int is64;
if (ptr != 0)
*ptr = 0;
if (elf == NULL)
return (0);
ELFRLOCK(elf);
if (elf->ed_kind != ELF_K_AR) {
ELFUNLOCK(elf);
_elf_seterr(EREQ_AR, 0);
return (0);
}
if ((as = (Byte *)elf->ed_arsym) == 0) {
ELFUNLOCK(elf);
return (0);
}
if (elf->ed_myflags & EDF_ASALLOC) {
if (ptr != 0)
*ptr = elf->ed_arsymsz;
ELFUNLOCK(elf);
/* LINTED */
return ((Elf_Arsym *)as);
}
is64 = (elf->ed_myflags & EDF_ARSYM64) != 0;
/*
* We're gonna need a write lock.
*/
ELFUNLOCK(elf)
ELFWLOCK(elf)
sz = elf->ed_arsymsz;
if (_elf_vm(elf, (size_t)(as - (Byte *)elf->ed_ident), sz) !=
OK_YES) {
ELFUNLOCK(elf);
return (0);
}
if ((elf->ed_arsym = arsym(as, sz, &elf->ed_arsymsz, is64)) == 0) {
ELFUNLOCK(elf);
return (0);
}
elf->ed_myflags |= EDF_ASALLOC;
if (ptr != 0)
*ptr = elf->ed_arsymsz;
rc = (Elf_Arsym *)elf->ed_arsym;
ELFUNLOCK(elf);
return (rc);
}
/*
* Private function to obtain the value sizeof() would return
* for a word from the symbol table from the given archive. Normally,
* this is an unimportant implementation detail hidden within
* elf_getarsym(). However, it is useful to elfdump for formatting the
* output correctly, and for the file command.
*
* exit:
* Returns 4 (32-bit) or 8 (64-bit) if a symbol table is present.
* Returns 0 in all other cases.
*/
size_t
_elf_getarsymwordsize(Elf *elf)
{
size_t size;
if (elf == NULL)
return (0);
ELFRLOCK(elf);
if ((elf->ed_kind == ELF_K_AR) && (elf->ed_arsym != 0))
size = (elf->ed_myflags & EDF_ARSYM64) ? 8 : 4;
else
size = 0;
ELFUNLOCK(elf);
return (size);
}
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