libcorkscrew/arch-arm/ptrace-arm.c

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "Corkscrew"
//#define LOG_NDEBUG 0

#include "../ptrace-arch.h"

#include <sys/exec_elf.h>
#include <cutils/log.h>

#ifndef PT_ARM_EXIDX
#define PT_ARM_EXIDX 0x70000001
#endif

static void load_exidx_header(pid_t pid, map_info_t* mi,
        uintptr_t* out_exidx_start, size_t* out_exidx_size) {
    uint32_t elf_phoff;
    uint32_t elf_phentsize_phnum;
    if (try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff)
            && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum),
                    &elf_phentsize_phnum)) {
        uint32_t elf_phentsize = elf_phentsize_phnum >> 16;
        uint32_t elf_phnum = elf_phentsize_phnum & 0xffff;
        for (uint32_t i = 0; i < elf_phnum; i++) {
            uintptr_t elf_phdr = mi->start + elf_phoff + i * elf_phentsize;
            uint32_t elf_phdr_type;
            if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_type), &elf_phdr_type)) {
                break;
            }
            if (elf_phdr_type == PT_ARM_EXIDX) {
                uint32_t elf_phdr_offset;
                uint32_t elf_phdr_filesz;
                if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_offset),
                        &elf_phdr_offset)
                        || !try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_filesz),
                                &elf_phdr_filesz)) {
                    break;
                }
                *out_exidx_start = mi->start + elf_phdr_offset;
                *out_exidx_size = elf_phdr_filesz / 8;
                ALOGV("Parsed EXIDX header info for %s: start=0x%08x, size=%d", mi->name,
                        *out_exidx_start, *out_exidx_size);
                return;
            }
        }
    }
    *out_exidx_start = 0;
    *out_exidx_size = 0;
}

void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data) {
    load_exidx_header(pid, mi, &data->exidx_start, &data->exidx_size);
}

void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data) {
}