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/*
* 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 <corkscrew/map_info.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <pthread.h>
#include <unistd.h>
#include <cutils/log.h>
#include <sys/time.h>
// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so\n
// 012345678901234567890123456789012345678901234567890123456789
// 0 1 2 3 4 5
static map_info_t* parse_maps_line(const char* line)
{
unsigned long int start;
unsigned long int end;
char permissions[5];
int name_pos;
if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d%n", &start, &end,
permissions, &name_pos) != 3) {
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;
}
map_info_t* mi = calloc(1, sizeof(map_info_t) + name_len + 1);
if (mi) {
mi->start = start;
mi->end = end;
mi->is_readable = strlen(permissions) == 4 && permissions[0] == 'r';
mi->is_executable = strlen(permissions) == 4 && permissions[2] == 'x';
mi->data = NULL;
memcpy(mi->name, name, name_len);
mi->name[name_len] = '\0';
ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
"is_readable=%d, is_executable=%d, name=%s",
mi->start, mi->end, mi->is_readable, mi->is_executable, mi->name);
}
return mi;
}
map_info_t* load_map_info_list(pid_t tid) {
char path[PATH_MAX];
char line[1024];
FILE* fp;
map_info_t* milist = NULL;
snprintf(path, PATH_MAX, "/proc/%d/maps", tid);
fp = fopen(path, "r");
if (fp) {
while(fgets(line, sizeof(line), fp)) {
map_info_t* mi = parse_maps_line(line);
if (mi) {
mi->next = milist;
milist = mi;
}
}
fclose(fp);
}
return milist;
}
void free_map_info_list(map_info_t* milist) {
while (milist) {
map_info_t* next = milist->next;
free(milist);
milist = next;
}
}
const map_info_t* find_map_info(const map_info_t* milist, uintptr_t addr) {
const map_info_t* mi = milist;
while (mi && !(addr >= mi->start && addr < mi->end)) {
mi = mi->next;
}
return mi;
}
bool is_readable_map(const map_info_t* milist, uintptr_t addr) {
const map_info_t* mi = find_map_info(milist, addr);
return mi && mi->is_readable;
}
bool is_executable_map(const map_info_t* milist, uintptr_t addr) {
const map_info_t* mi = find_map_info(milist, addr);
return mi && mi->is_executable;
}
static pthread_mutex_t g_my_map_info_list_mutex = PTHREAD_MUTEX_INITIALIZER;
static map_info_t* g_my_map_info_list = NULL;
static const int64_t MAX_CACHE_AGE = 5 * 1000 * 1000000LL;
typedef struct {
uint32_t refs;
int64_t timestamp;
} my_map_info_data_t;
static int64_t now() {
struct timespec t;
t.tv_sec = t.tv_nsec = 0;
clock_gettime(CLOCK_MONOTONIC, &t);
return t.tv_sec * 1000000000LL + t.tv_nsec;
}
static void dec_ref(map_info_t* milist, my_map_info_data_t* data) {
if (!--data->refs) {
ALOGV("Freed my_map_info_list %p.", milist);
free(data);
free_map_info_list(milist);
}
}
map_info_t* acquire_my_map_info_list() {
pthread_mutex_lock(&g_my_map_info_list_mutex);
int64_t time = now();
if (g_my_map_info_list) {
my_map_info_data_t* data = (my_map_info_data_t*)g_my_map_info_list->data;
int64_t age = time - data->timestamp;
if (age >= MAX_CACHE_AGE) {
ALOGV("Invalidated my_map_info_list %p, age=%lld.", g_my_map_info_list, age);
dec_ref(g_my_map_info_list, data);
g_my_map_info_list = NULL;
} else {
ALOGV("Reusing my_map_info_list %p, age=%lld.", g_my_map_info_list, age);
}
}
if (!g_my_map_info_list) {
my_map_info_data_t* data = (my_map_info_data_t*)malloc(sizeof(my_map_info_data_t));
g_my_map_info_list = load_map_info_list(getpid());
if (g_my_map_info_list) {
ALOGV("Loaded my_map_info_list %p.", g_my_map_info_list);
g_my_map_info_list->data = data;
data->refs = 1;
data->timestamp = time;
} else {
free(data);
}
}
map_info_t* milist = g_my_map_info_list;
if (milist) {
my_map_info_data_t* data = (my_map_info_data_t*)g_my_map_info_list->data;
data->refs += 1;
}
pthread_mutex_unlock(&g_my_map_info_list_mutex);
return milist;
}
void release_my_map_info_list(map_info_t* milist) {
if (milist) {
pthread_mutex_lock(&g_my_map_info_list_mutex);
my_map_info_data_t* data = (my_map_info_data_t*)milist->data;
dec_ref(milist, data);
pthread_mutex_unlock(&g_my_map_info_list_mutex);
}
}
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