minix/lib/libelf/libelf_ar_util.c

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2011-05-21 19:11:59 +02:00
/*-
* Copyright (c) 2006,2009,2010 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 <assert.h>
#include <libelf.h>
#include <stdlib.h>
#include <string.h>
#include "_libelf.h"
#include "_libelf_ar.h"
LIBELF_VCSID("$Id$");
/*
* Convert a string bounded by `start' and `start+sz' (exclusive) to a
* number in the specified base.
*/
int
_libelf_ar_get_number(const char *s, size_t sz, int base, size_t *ret)
{
int c, v;
size_t r;
const char *e;
assert(base <= 10);
e = s + sz;
/* skip leading blanks */
for (;s < e && (c = *s) == ' '; s++)
;
r = 0L;
for (;s < e; s++) {
if ((c = *s) == ' ')
break;
if (c < '0' || c > '9')
return (0);
v = c - '0';
if (v >= base) /* Illegal digit. */
break;
r *= base;
r += v;
}
*ret = r;
return (1);
}
/*
* Return the translated name for an archive member.
*/
char *
_libelf_ar_get_translated_name(const struct ar_hdr *arh, Elf *ar)
{
char c, *s;
size_t len, offset;
const char *buf, *p, *q, *r;
const size_t bufsize = sizeof(arh->ar_name);
assert(arh != NULL);
assert(ar->e_kind == ELF_K_AR);
assert((const char *) arh >= ar->e_rawfile &&
(const char *) arh < ar->e_rawfile + ar->e_rawsize);
buf = arh->ar_name;
/*
* Check for extended naming.
*
* If the name matches the pattern "^/[0-9]+", it is an
* SVR4-style extended name. If the name matches the pattern
* "#1/[0-9]+", the entry uses BSD style extended naming.
*/
if (buf[0] == '/' && (c = buf[1]) >= '0' && c <= '9') {
/*
* The value in field ar_name is a decimal offset into
* the archive string table where the actual name
* resides.
*/
if (_libelf_ar_get_number(buf + 1, bufsize - 1, 10,
&offset) == 0) {
LIBELF_SET_ERROR(ARCHIVE, 0);
return (NULL);
}
if (offset > ar->e_u.e_ar.e_rawstrtabsz) {
LIBELF_SET_ERROR(ARCHIVE, 0);
return (NULL);
}
p = q = ar->e_u.e_ar.e_rawstrtab + offset;
r = ar->e_u.e_ar.e_rawstrtab + ar->e_u.e_ar.e_rawstrtabsz;
for (; p < r && *p != '/'; p++)
;
len = p - q + 1; /* space for the trailing NUL */
if ((s = malloc(len)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
(void) strncpy(s, q, len);
s[len - 1] = '\0';
return (s);
} else if (IS_EXTENDED_BSD_NAME(buf)) {
r = buf + LIBELF_AR_BSD_EXTENDED_NAME_PREFIX_SIZE;
if (_libelf_ar_get_number(r, bufsize -
LIBELF_AR_BSD_EXTENDED_NAME_PREFIX_SIZE, 10,
&len) == 0) {
LIBELF_SET_ERROR(ARCHIVE, 0);
return (NULL);
}
/*
* Allocate space for the file name plus a
* trailing NUL.
*/
if ((s = malloc(len + 1)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
/*
* The file name follows the archive header.
*/
q = (const char *) (arh + 1);
(void) strncpy(s, q, len);
s[len] = '\0';
return (s);
}
/*
* A 'normal' name.
*
* Skip back over trailing blanks from the end of the field.
* In the SVR4 format, a '/' is used as a terminator for
* non-special names.
*/
for (q = buf + bufsize - 1; q >= buf && *q == ' '; --q)
;
if (q >= buf) {
if (*q == '/') {
/*
* SVR4 style names: ignore the trailing
* character '/', but only if the name is not
* one of the special names "/" and "//".
*/
if (q > buf + 1 ||
(q == (buf + 1) && *buf != '/'))
q--;
}
len = q - buf + 2; /* Add space for a trailing NUL. */
} else {
/* The buffer only had blanks. */
buf = "";
len = 1;
}
if ((s = malloc(len)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
(void) strncpy(s, buf, len);
s[len - 1] = '\0';
return (s);
}
/*
* Return the raw name for an archive member, inclusive of any
* formatting characters.
*/
char *
_libelf_ar_get_raw_name(const struct ar_hdr *arh)
{
char *rawname;
const size_t namesz = sizeof(arh->ar_name);
if ((rawname = malloc(namesz + 1)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
(void) strncpy(rawname, arh->ar_name, namesz);
rawname[namesz] = '\0';
return (rawname);
}
/*
* Open an 'ar' archive.
*/
Elf *
_libelf_ar_open(Elf *e)
{
int scanahead;
char *s, *end;
size_t sz;
struct ar_hdr arh;
e->e_kind = ELF_K_AR;
e->e_u.e_ar.e_nchildren = 0;
e->e_u.e_ar.e_next = (off_t) -1;
/*
* Look for special members.
*/
s = e->e_rawfile + SARMAG;
end = e->e_rawfile + e->e_rawsize;
assert(e->e_rawsize > 0);
/*
* We use heuristics to determine the flavor of the archive we
* are examining.
*
* SVR4 flavor archives use the name "/ " and "// " for
* special members.
*
* In BSD flavor archives the symbol table, if present, is the
* first archive with name "__.SYMDEF".
*/
#define READ_AR_HEADER(S, ARH, SZ, END) \
do { \
if ((S) + sizeof((ARH)) > (END)) \
goto error; \
(void) memcpy(&(ARH), (S), sizeof((ARH))); \
if ((ARH).ar_fmag[0] != '`' || (ARH).ar_fmag[1] != '\n') \
goto error; \
if (_libelf_ar_get_number((ARH).ar_size, \
sizeof((ARH).ar_size), 10, &(SZ)) == 0) \
goto error; \
} while (0)
READ_AR_HEADER(s, arh, sz, end);
/*
* Handle special archive members for the SVR4 format.
*/
if (arh.ar_name[0] == '/') {
assert(sz > 0);
e->e_flags |= LIBELF_F_AR_VARIANT_SVR4;
scanahead = 0;
/*
* The symbol table (file name "/ ") always comes before the
* string table (file name "// ").
*/
if (arh.ar_name[1] == ' ') {
/* "/ " => symbol table. */
scanahead = 1; /* The string table to follow. */
s += sizeof(arh);
e->e_u.e_ar.e_rawsymtab = s;
e->e_u.e_ar.e_rawsymtabsz = sz;
sz = LIBELF_ADJUST_AR_SIZE(sz);
s += sz;
} else if (arh.ar_name[1] == '/' && arh.ar_name[2] == ' ') {
/* "// " => string table for long file names. */
s += sizeof(arh);
e->e_u.e_ar.e_rawstrtab = s;
e->e_u.e_ar.e_rawstrtabsz = sz;
sz = LIBELF_ADJUST_AR_SIZE(sz);
s += sz;
}
/*
* If the string table hasn't been seen yet, look for
* it in the next member.
*/
if (scanahead) {
READ_AR_HEADER(s, arh, sz, end);
if (arh.ar_name[0] == '/' && arh.ar_name[1] == '/' &&
arh.ar_name[2] == ' ') {
/* "// " => string table for long file names. */
s += sizeof(arh);
e->e_u.e_ar.e_rawstrtab = s;
e->e_u.e_ar.e_rawstrtabsz = sz;
sz = LIBELF_ADJUST_AR_SIZE(sz);
s += sz;
}
}
} else if (strncmp(arh.ar_name, LIBELF_AR_BSD_SYMTAB_NAME,
sizeof(LIBELF_AR_BSD_SYMTAB_NAME) - 1) == 0) {
/*
* BSD style archive symbol table.
*/
s += sizeof(arh);
e->e_u.e_ar.e_rawsymtab = s;
e->e_u.e_ar.e_rawsymtabsz = sz;
sz = LIBELF_ADJUST_AR_SIZE(sz);
s += sz;
}
/*
* Update the 'next' offset, so that a subsequent elf_begin()
* works as expected.
*/
e->e_u.e_ar.e_next = (off_t) (s - e->e_rawfile);
return (e);
error:
LIBELF_SET_ERROR(ARCHIVE, 0);
return (NULL);
}