unwind-dw2-fde-glibc.c [plain text]
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include "auto-host.h"
#include "tconfig.h"
#ifndef inhibit_libc
#include <stddef.h>
#include <stdlib.h>
#include <link.h>
#endif
#include "tsystem.h"
#include "dwarf2.h"
#include "unwind.h"
#define NO_BASE_OF_ENCODED_VALUE
#include "unwind-pe.h"
#include "unwind-dw2-fde.h"
#include "gthr.h"
#if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
&& (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
|| (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
static fde * _Unwind_Find_registered_FDE (void *pc, struct dwarf_eh_bases *bases);
#define _Unwind_Find_FDE _Unwind_Find_registered_FDE
#include "unwind-dw2-fde.c"
#undef _Unwind_Find_FDE
#ifndef PT_GNU_EH_FRAME
#define PT_GNU_EH_FRAME (PT_LOOS + 0x474e550)
#endif
struct unw_eh_callback_data
{
_Unwind_Ptr pc;
void *tbase;
void *dbase;
void *func;
fde *ret;
};
struct unw_eh_frame_hdr
{
unsigned char version;
unsigned char eh_frame_ptr_enc;
unsigned char fde_count_enc;
unsigned char table_enc;
};
static _Unwind_Ptr
base_from_cb_data (unsigned char encoding, struct unw_eh_callback_data *data)
{
if (encoding == DW_EH_PE_omit)
return 0;
switch (encoding & 0x70)
{
case DW_EH_PE_absptr:
case DW_EH_PE_pcrel:
case DW_EH_PE_aligned:
return 0;
case DW_EH_PE_textrel:
return (_Unwind_Ptr) data->tbase;
case DW_EH_PE_datarel:
return (_Unwind_Ptr) data->dbase;
}
abort ();
}
static int
_Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
{
struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr;
const ElfW(Phdr) *phdr, *p_eh_frame_hdr, *p_dynamic;
long n, match;
_Unwind_Ptr load_base;
const unsigned char *p;
const struct unw_eh_frame_hdr *hdr;
_Unwind_Ptr eh_frame;
struct object ob;
if (size < offsetof (struct dl_phdr_info, dlpi_phnum)
+ sizeof (info->dlpi_phnum))
return -1;
match = 0;
phdr = info->dlpi_phdr;
load_base = info->dlpi_addr;
p_eh_frame_hdr = NULL;
p_dynamic = NULL;
for (n = info->dlpi_phnum; --n >= 0; phdr++)
{
if (phdr->p_type == PT_LOAD)
{
_Unwind_Ptr vaddr = phdr->p_vaddr + load_base;
if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
match = 1;
}
else if (phdr->p_type == PT_GNU_EH_FRAME)
p_eh_frame_hdr = phdr;
else if (phdr->p_type == PT_DYNAMIC)
p_dynamic = phdr;
}
if (!match || !p_eh_frame_hdr)
return 0;
hdr = (const struct unw_eh_frame_hdr *)
(p_eh_frame_hdr->p_vaddr + load_base);
if (hdr->version != 1)
return 1;
#ifdef CRT_GET_RFIB_DATA
# ifdef __i386__
data->dbase = NULL;
if (p_dynamic)
{
ElfW(Dyn) *dyn = (ElfW(Dyn) *) (p_dynamic->p_vaddr + load_base);
for (; dyn->d_tag != DT_NULL ; dyn++)
if (dyn->d_tag == DT_PLTGOT)
{
data->dbase = (void *) dyn->d_un.d_ptr;
break;
}
}
# else
# error What is DW_EH_PE_datarel base on this platform?
# endif
#endif
#ifdef CRT_GET_RFIB_TEXT
# error What is DW_EH_PE_textrel base on this platform?
#endif
p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc,
base_from_cb_data (hdr->eh_frame_ptr_enc,
data),
(const unsigned char *) (hdr + 1),
&eh_frame);
if (hdr->fde_count_enc != DW_EH_PE_omit
&& hdr->table_enc == (DW_EH_PE_datarel | DW_EH_PE_sdata4))
{
_Unwind_Ptr fde_count;
p = read_encoded_value_with_base (hdr->fde_count_enc,
base_from_cb_data (hdr->fde_count_enc,
data),
p, &fde_count);
if (fde_count == 0)
return 1;
if ((((_Unwind_Ptr) p) & 3) == 0)
{
struct fde_table {
signed initial_loc __attribute__ ((mode (SI)));
signed fde __attribute__ ((mode (SI)));
};
const struct fde_table *table = (const struct fde_table *) p;
size_t lo, hi, mid;
_Unwind_Ptr data_base = (_Unwind_Ptr) hdr;
fde *f;
unsigned int f_enc, f_enc_size;
_Unwind_Ptr range;
mid = fde_count - 1;
if (data->pc < table[0].initial_loc + data_base)
return 1;
else if (data->pc < table[mid].initial_loc + data_base)
{
lo = 0;
hi = mid;
while (lo < hi)
{
mid = (lo + hi) / 2;
if (data->pc < table[mid].initial_loc + data_base)
hi = mid;
else if (data->pc >= table[mid + 1].initial_loc + data_base)
lo = mid + 1;
else
break;
}
if (lo >= hi)
__gxx_abort ();
}
f = (fde *) (table[mid].fde + data_base);
f_enc = get_fde_encoding (f);
f_enc_size = size_of_encoded_value (f_enc);
read_encoded_value_with_base (f_enc & 0x0f, 0,
&f->pc_begin[f_enc_size], &range);
if (data->pc < table[mid].initial_loc + data_base + range)
data->ret = f;
data->func = (void *) (table[mid].initial_loc + data_base);
return 1;
}
}
ob.pc_begin = NULL;
ob.tbase = data->tbase;
ob.dbase = data->dbase;
ob.u.single = (fde *) eh_frame;
ob.s.i = 0;
ob.s.b.mixed_encoding = 1;
data->ret = linear_search_fdes (&ob, (fde *) eh_frame, (void *) data->pc);
if (data->ret != NULL)
{
unsigned int encoding = get_fde_encoding (data->ret);
read_encoded_value_with_base (encoding,
base_from_cb_data (encoding, data),
data->ret->pc_begin,
(_Unwind_Ptr *)&data->func);
}
return 1;
}
fde *
_Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
{
struct unw_eh_callback_data data;
fde *ret;
ret = _Unwind_Find_registered_FDE (pc, bases);
if (ret != NULL)
return ret;
data.pc = (_Unwind_Ptr) pc;
data.tbase = NULL;
data.dbase = NULL;
data.func = NULL;
data.ret = NULL;
if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0)
return NULL;
if (data.ret)
{
bases->tbase = data.tbase;
bases->dbase = data.dbase;
bases->func = data.func;
}
return data.ret;
}
#else
#define _Unwind_Find_FDE _Unwind_Find_FDE
#include "unwind-dw2-fde.c"
#endif