freebsd-dev/lib/libc/ia64/gen/unwind.c

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/*
* Copyright (c) 2002 Marcel Moolenaar
* 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 ``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 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <assert.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <machine/elf.h>
#ifndef PT_IA_64_UNWIND
#define PT_IA_64_UNWIND 0x70000001
#endif
#define SANITY 0
struct ia64_unwind_entry
{
Elf64_Addr start;
Elf64_Addr end;
Elf64_Addr descr;
};
struct ia64_unwind_entry *
_Unwind_FindTableEntry(const void *pc, unsigned long *pseg, unsigned long *pgp)
{
Dl_info info;
Elf_Dyn *dyn;
Elf_Ehdr *ehdr;
Elf_Phdr *phdr;
char *p, *p_top;
struct ia64_unwind_entry *unw, *res;
register unsigned long gp __asm__("gp"); /* XXX assumes gcc */
size_t l, m, r;
if (!dladdr(pc, &info))
return NULL;
ehdr = (Elf_Ehdr*)info.dli_fbase;
#if SANITY
assert(IS_ELF(*ehdr));
assert(ehdr->e_ident[EI_CLASS] == ELFCLASS64);
assert(ehdr->e_ident[EI_DATA] == ELFDATA2LSB);
assert(ehdr->e_machine == EM_IA_64);
#endif
*pgp = gp;
*pseg = 0UL;
res = NULL;
p = (char*)info.dli_fbase + ehdr->e_phoff;
p_top = p + ehdr->e_phnum * ehdr->e_phentsize;
while (p < p_top) {
phdr = (Elf_Phdr*)p;
switch (phdr->p_type) {
case PT_DYNAMIC:
dyn = (Elf_Dyn*)phdr->p_vaddr;
while (dyn->d_tag != DT_NULL) {
if (dyn->d_tag == DT_PLTGOT) {
*pgp = dyn->d_un.d_ptr;
break;
}
dyn++;
}
break;
case PT_LOAD:
if (pc >= (void*)phdr->p_vaddr &&
pc < (void*)(phdr->p_vaddr + phdr->p_memsz))
*pseg = phdr->p_vaddr;
break;
case PT_IA_64_UNWIND:
#if SANITY
assert(*pseg != 0UL);
assert(res == NULL);
#endif
unw = (struct ia64_unwind_entry*)phdr->p_vaddr;
l = 0;
r = phdr->p_memsz / sizeof(struct ia64_unwind_entry);
while (l < r) {
m = (l + r) >> 1;
res = unw + m;
if (pc < (void*)(res->start + *pseg))
r = m;
else if (pc >= (void*)(res->end + *pseg))
l = m + 1;
else
break; /* found */
}
if (l >= r)
res = NULL;
break;
}
p += ehdr->e_phentsize;
}
return res;
}