diff options
Diffstat (limited to 'libcorkscrew/map_info.c')
| -rw-r--r-- | libcorkscrew/map_info.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/libcorkscrew/map_info.c b/libcorkscrew/map_info.c new file mode 100644 index 0000000..f33378f --- /dev/null +++ b/libcorkscrew/map_info.c @@ -0,0 +1,190 @@ +/* + * 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); + } +} |