Fix for Bug 3671 - QEMU GDB stub listens on IPv6-only port on Windows 7
The connection string used by the GDB stub does not specify which
version of the Internet Protocol should be used by the port on
which it listens. On host platforms with IPv6 support, such as
Windows 7, this means that the stub listens on an IPv6-only port.
Since the GDB client uses IPv4, this means that the client cannot
connect to QEMU.
/*
* strptr.c - implementation of the elf_strptr(3) function.
* Copyright (C) 1995 - 2007 Michael Riepe
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <private.h>
#ifndef lint
static const char rcsid[] = "@(#) $Id: strptr.c,v 1.11 2007/09/07 12:07:59 michael Exp $";
#endif /* lint */
char*
elf_strptr(Elf *elf, size_t section, size_t offset) {
Elf_Data *data;
Elf_Scn *scn;
size_t n;
char *s;
if (!elf) {
return NULL;
}
elf_assert(elf->e_magic == ELF_MAGIC);
if (!(scn = elf_getscn(elf, section))) {
return NULL;
}
if (scn->s_index == SHN_UNDEF) {
seterr(ERROR_NOSTRTAB);
return NULL;
}
/*
* checking the section header is more appropriate
*/
if (elf->e_class == ELFCLASS32) {
if (scn->s_shdr32.sh_type != SHT_STRTAB) {
seterr(ERROR_NOSTRTAB);
return NULL;
}
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
if (scn->s_shdr64.sh_type != SHT_STRTAB) {
seterr(ERROR_NOSTRTAB);
return NULL;
}
}
#endif /* __LIBELF64 */
else if (valid_class(elf->e_class)) {
seterr(ERROR_UNIMPLEMENTED);
return NULL;
}
else {
seterr(ERROR_UNKNOWN_CLASS);
return NULL;
}
/*
* Find matching buffer
*/
n = 0;
data = NULL;
if (elf->e_elf_flags & ELF_F_LAYOUT) {
/*
* Programmer is responsible for d_off
* Note: buffers may be in any order!
*/
while ((data = elf_getdata(scn, data))) {
n = data->d_off;
if (offset >= n && offset - n < data->d_size) {
/*
* Found it
*/
break;
}
}
}
else {
/*
* Calculate offsets myself
*/
while ((data = elf_getdata(scn, data))) {
if (data->d_align > 1) {
n += data->d_align - 1;
n -= n % data->d_align;
}
if (offset < n) {
/*
* Invalid offset: points into a hole
*/
seterr(ERROR_BADSTROFF);
return NULL;
}
if (offset - n < data->d_size) {
/*
* Found it
*/
break;
}
n += data->d_size;
}
}
if (data == NULL) {
/*
* Not found
*/
seterr(ERROR_BADSTROFF);
return NULL;
}
if (data->d_buf == NULL) {
/*
* Buffer is NULL (usually the programmers' fault)
*/
seterr(ERROR_NULLBUF);
return NULL;
}
offset -= n;
s = (char*)data->d_buf;
if (!(_elf_sanity_checks & SANITY_CHECK_STRPTR)) {
return s + offset;
}
/*
* Perform extra sanity check
*/
for (n = offset; n < data->d_size; n++) {
if (s[n] == '\0') {
/*
* Return properly NUL terminated string
*/
return s + offset;
}
}
/*
* String is not NUL terminated
* Return error to avoid SEGV in application
*/
seterr(ERROR_UNTERM);
return NULL;
}