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/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <ctype.h>
#include <elf.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "debug_mapinfo.h"
#include "malloc_debug_disable.h"
#if defined(__LP64__)
#define Elf_W(x) Elf64_##x
#else
#define Elf_W(x) Elf32_##x
#endif
// Format of /proc/<PID>/maps:
// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so
static mapinfo_t* parse_maps_line(char* line) {
uintptr_t start;
uintptr_t end;
uintptr_t offset;
char permissions[4];
int name_pos;
if (sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %4s %" PRIxPTR " %*x:%*x %*d%n", &start,
&end, permissions, &offset, &name_pos) < 2) {
return NULL;
}
while (isspace(line[name_pos])) {
name_pos += 1;
}
const char* name = line + name_pos;
size_t name_len = strlen(name);
if (name_len && name[name_len - 1] == '\n') {
name_len -= 1;
}
mapinfo_t* mi = reinterpret_cast<mapinfo_t*>(calloc(1, sizeof(mapinfo_t) + name_len + 1));
if (mi) {
mi->start = start;
mi->end = end;
mi->offset = offset;
if (permissions[0] != 'r') {
// Any unreadable map will just get a zero load base.
mi->load_base = 0;
mi->load_base_read = true;
} else {
mi->load_base_read = false;
}
memcpy(mi->name, name, name_len);
mi->name[name_len] = '\0';
}
return mi;
}
__LIBC_HIDDEN__ mapinfo_t* mapinfo_create(pid_t pid) {
ScopedDisableDebugCalls disable;
struct mapinfo_t* milist = NULL;
char data[1024]; // Used to read lines as well as to construct the filename.
snprintf(data, sizeof(data), "/proc/%d/maps", pid);
FILE* fp = fopen(data, "re");
if (fp != NULL) {
while (fgets(data, sizeof(data), fp) != NULL) {
mapinfo_t* mi = parse_maps_line(data);
if (mi) {
mi->next = milist;
milist = mi;
}
}
fclose(fp);
}
return milist;
}
__LIBC_HIDDEN__ void mapinfo_destroy(mapinfo_t* mi) {
ScopedDisableDebugCalls disable;
while (mi != NULL) {
mapinfo_t* del = mi;
mi = mi->next;
free(del);
}
}
template<typename T>
static inline bool get_val(mapinfo_t* mi, uintptr_t addr, T* store) {
if (addr < mi->start || addr + sizeof(T) > mi->end) {
return false;
}
// Make sure the address is aligned properly.
if (addr & (sizeof(T)-1)) {
return false;
}
*store = *reinterpret_cast<T*>(addr);
return true;
}
__LIBC_HIDDEN__ void mapinfo_read_loadbase(mapinfo_t* mi) {
mi->load_base = 0;
mi->load_base_read = true;
uintptr_t addr = mi->start;
Elf_W(Ehdr) ehdr;
if (!get_val<Elf_W(Half)>(mi, addr + offsetof(Elf_W(Ehdr), e_phnum), &ehdr.e_phnum)) {
return;
}
if (!get_val<Elf_W(Off)>(mi, addr + offsetof(Elf_W(Ehdr), e_phoff), &ehdr.e_phoff)) {
return;
}
addr += ehdr.e_phoff;
for (size_t i = 0; i < ehdr.e_phnum; i++) {
Elf_W(Phdr) phdr;
if (!get_val<Elf_W(Word)>(mi, addr + offsetof(Elf_W(Phdr), p_type), &phdr.p_type)) {
return;
}
if (!get_val<Elf_W(Off)>(mi, addr + offsetof(Elf_W(Phdr), p_offset), &phdr.p_offset)) {
return;
}
if (phdr.p_type == PT_LOAD && phdr.p_offset == mi->offset) {
if (!get_val<Elf_W(Addr)>(mi, addr + offsetof(Elf_W(Phdr), p_vaddr), &phdr.p_vaddr)) {
return;
}
mi->load_base = phdr.p_vaddr;
return;
}
addr += sizeof(phdr);
}
}
// Find the containing map info for the PC.
__LIBC_HIDDEN__ const mapinfo_t* mapinfo_find(mapinfo_t* mi, uintptr_t pc, uintptr_t* rel_pc) {
for (; mi != NULL; mi = mi->next) {
if ((pc >= mi->start) && (pc < mi->end)) {
if (!mi->load_base_read) {
mapinfo_read_loadbase(mi);
}
*rel_pc = pc - mi->start + mi->load_base;
return mi;
}
}
*rel_pc = pc;
return NULL;
}
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