/*
* This file is part of ltrace.
* Copyright (C) 2013 Petr Machata, Red Hat Inc.
* Copyright (C) 2010 Zach Welch, CodeSourcery
* Copyright (C) 2004,2008,2009 Juan Cespedes
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <gelf.h>
#include <stdio.h>
#include <string.h>
#include "proc.h"
#include "library.h"
#include "ltrace-elf.h"
static int
get_hardfp(uint64_t abi_vfp_args)
{
if (abi_vfp_args == 2)
fprintf(stderr,
"Tag_ABI_VFP_args value 2 (tool chain-specific "
"conventions) not supported.\n");
return abi_vfp_args == 1;
}
int
arch_elf_init(struct ltelf *lte, struct library *lib)
{
GElf_Addr jmprel_addr;
Elf_Scn *jmprel_sec;
GElf_Shdr jmprel_shdr;
if (elf_load_dynamic_entry(lte, DT_JMPREL, &jmprel_addr) < 0
|| elf_get_section_covering(lte, jmprel_addr,
&jmprel_sec, &jmprel_shdr) < 0
|| jmprel_sec == NULL)
return -1;
lte->arch.jmprel_data = elf_loaddata(jmprel_sec, &jmprel_shdr);
if (lte->arch.jmprel_data == NULL)
return -1;
/* Nothing in this section is strictly critical. It's not
* that much of a deal if we fail to guess right whether the
* ABI is softfp or hardfp. */
unsigned hardfp = 0;
Elf_Scn *scn;
Elf_Data *data;
GElf_Shdr shdr;
if (elf_get_section_type(lte, SHT_ARM_ATTRIBUTES, &scn, &shdr) < 0
|| (scn != NULL && (data = elf_loaddata(scn, &shdr)) == NULL)) {
fprintf(stderr,
"Error when obtaining ARM attribute section: %s\n",
elf_errmsg(-1));
goto done;
} else if (scn != NULL && data != NULL) {
GElf_Xword offset = 0;
uint8_t version;
if (elf_read_next_u8(data, &offset, &version) < 0) {
goto done;
} else if (version != 'A') {
fprintf(stderr, "Unsupported ARM attribute section "
"version %d ('%c').\n", version, version);
goto done;
}
do {
const char signature[] = "aeabi";
/* N.B. LEN is including the length field
* itself. */
uint32_t sec_len;
if (elf_read_u32(data, offset, &sec_len) < 0
|| !elf_can_read_next(data, offset, sec_len)) {
goto done;
}
const GElf_Xword next_offset = offset + sec_len;
offset += 4;
if (sec_len < 4 + sizeof signature
|| strcmp(signature, data->d_buf + offset) != 0)
goto skip;
offset += sizeof signature;
const GElf_Xword offset0 = offset;
uint64_t tag;
uint32_t sub_len;
if (elf_read_next_uleb128(data, &offset, &tag) < 0
|| elf_read_next_u32(data, &offset, &sub_len) < 0
|| !elf_can_read_next(data, offset0, sub_len))
goto done;
if (tag != 1)
/* IHI0045D_ABI_addenda: "section and
* symbol attributes are deprecated
* [...] consumers are permitted to
* ignore them." */
goto skip;
while (offset < offset0 + sub_len) {
if (elf_read_next_uleb128(data,
&offset, &tag) < 0)
goto done;
switch (tag) {
uint64_t v;
case 6: /* Tag_CPU_arch */
case 7: /* Tag_CPU_arch_profile */
case 8: /* Tag_ARM_ISA_use */
case 9: /* Tag_THUMB_ISA_use */
case 10: /* Tag_FP_arch */
case 11: /* Tag_WMMX_arch */
case 12: /* Tag_Advanced_SIMD_arch */
case 13: /* Tag_PCS_config */
case 14: /* Tag_ABI_PCS_R9_use */
case 15: /* Tag_ABI_PCS_RW_data */
case 16: /* Tag_ABI_PCS_RO_data */
case 17: /* Tag_ABI_PCS_GOT_use */
case 18: /* Tag_ABI_PCS_wchar_t */
case 19: /* Tag_ABI_FP_rounding */
case 20: /* Tag_ABI_FP_denormal */
case 21: /* Tag_ABI_FP_exceptions */
case 22: /* Tag_ABI_FP_user_exceptions */
case 23: /* Tag_ABI_FP_number_model */
case 24: /* Tag_ABI_align_needed */
case 25: /* Tag_ABI_align_preserved */
case 26: /* Tag_ABI_enum_size */
case 27: /* Tag_ABI_HardFP_use */
case 28: /* Tag_ABI_VFP_args */
case 29: /* Tag_ABI_WMMX_args */
case 30: /* Tag_ABI_optimization_goals */
case 31: /* Tag_ABI_FP_optimization_goals */
case 32: /* Tag_compatibility */
case 34: /* Tag_CPU_unaligned_access */
case 36: /* Tag_FP_HP_extension */
case 38: /* Tag_ABI_FP_16bit_format */
case 42: /* Tag_MPextension_use */
case 70: /* Tag_MPextension_use as well */
case 44: /* Tag_DIV_use */
case 64: /* Tag_nodefaults */
case 66: /* Tag_T2EE_use */
case 68: /* Tag_Virtualization_use */
uleb128:
if (elf_read_next_uleb128
(data, &offset, &v) < 0)
goto done;
if (tag == 28)
hardfp = get_hardfp(v);
if (tag != 32)
continue;
/* Tag 32 has two arguments,
* fall through. */
case 4: /* Tag_CPU_raw_name */
case 5: /* Tag_CPU_name */
case 65: /* Tag_also_compatible_with */
case 67: /* Tag_conformance */
ntbs:
offset += strlen(data->d_buf
+ offset) + 1;
continue;
}
/* Handle unknown tags in a generic
* manner, if possible. */
if (tag <= 32) {
fprintf(stderr,
"Unknown tag %lld "
"at offset %#llx "
"of ARM attribute section.",
tag, offset);
goto skip;
} else if (tag % 2 == 0) {
goto uleb128;
} else {
goto ntbs;
}
}
skip:
offset = next_offset;
} while (elf_can_read_next(data, offset, 1));
}
done:
lib->arch.hardfp = hardfp;
return 0;
}
void
arch_elf_destroy(struct ltelf *lte)
{
}
static int
arch_plt_entry_has_stub(struct ltelf *lte, size_t off) {
char *buf = (char *) lte->arch.jmprel_data->d_buf;
uint16_t op = *(uint16_t *) (buf + off);
return op == 0x4778;
}
GElf_Addr
arch_plt_sym_val(struct ltelf *lte, size_t ndx, GElf_Rela * rela) {
size_t start = lte->arch.jmprel_data->d_size + 12;
size_t off = start + 20, i;
for (i = 0; i < ndx; i++)
off += arch_plt_entry_has_stub(lte, off) ? 16 : 12;
if (arch_plt_entry_has_stub(lte, off))
off += 4;
return lte->plt_addr + off - start;
}
void *
sym2addr(struct process *proc, struct library_symbol *sym)
{
return sym->enter_addr;
}
int
arch_library_init(struct library *lib)
{
return 0;
}
void
arch_library_destroy(struct library *lib)
{
}
int
arch_library_clone(struct library *retp, struct library *lib)
{
retp->arch = lib->arch;
return 0;
}