1 /*
2  * Copyright (C) 2013 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <ctype.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <limits.h>
22 #include <pthread.h>
23 #include <unistd.h>
24 #include <log/log.h>
25 #include <sys/time.h>
26 
27 #include <backtrace/backtrace.h>
28 
29 #if defined(__APPLE__)
30 
31 // Mac OS vmmap(1) output:
32 // __TEXT                 0009f000-000a1000 [    8K     8K] r-x/rwx SM=COW  /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
33 // 012345678901234567890123456789012345678901234567890123456789
34 // 0         1         2         3         4         5
parse_vmmap_line(const char * line)35 static backtrace_map_info_t* parse_vmmap_line(const char* line) {
36   unsigned long int start;
37   unsigned long int end;
38   char permissions[4];
39   int name_pos;
40   if (sscanf(line, "%*21c %lx-%lx [%*13c] %3c/%*3c SM=%*3c  %n",
41              &start, &end, permissions, &name_pos) != 3) {
42     return NULL;
43   }
44 
45   const char* name = line + name_pos;
46   size_t name_len = strlen(name);
47 
48   backtrace_map_info_t* mi = calloc(1, sizeof(backtrace_map_info_t) + name_len);
49   if (mi != NULL) {
50     mi->start = start;
51     mi->end = end;
52     mi->is_readable = permissions[0] == 'r';
53     mi->is_writable = permissions[1] == 'w';
54     mi->is_executable = permissions[2] == 'x';
55     memcpy(mi->name, name, name_len);
56     mi->name[name_len - 1] = '\0';
57     ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
58           "is_readable=%d, is_writable=%d is_executable=%d, name=%s",
59           mi->start, mi->end,
60           mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
61   }
62   return mi;
63 }
64 
backtrace_create_map_info_list(pid_t pid)65 backtrace_map_info_t* backtrace_create_map_info_list(pid_t pid) {
66   char cmd[1024];
67   if (pid < 0) {
68     pid = getpid();
69   }
70   snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid);
71   FILE* fp = popen(cmd, "r");
72   if (fp == NULL) {
73     return NULL;
74   }
75 
76   char line[1024];
77   backtrace_map_info_t* milist = NULL;
78   while (fgets(line, sizeof(line), fp) != NULL) {
79     backtrace_map_info_t* mi = parse_vmmap_line(line);
80     if (mi != NULL) {
81       mi->next = milist;
82       milist = mi;
83     }
84   }
85   pclose(fp);
86   return milist;
87 }
88 
89 #else
90 
91 // Linux /proc/<pid>/maps lines:
92 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so\n
93 // 012345678901234567890123456789012345678901234567890123456789
94 // 0         1         2         3         4         5
parse_maps_line(const char * line)95 static backtrace_map_info_t* parse_maps_line(const char* line)
96 {
97   unsigned long int start;
98   unsigned long int end;
99   char permissions[5];
100   int name_pos;
101   if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d%n", &start, &end,
102              permissions, &name_pos) != 3) {
103     return NULL;
104   }
105 
106   while (isspace(line[name_pos])) {
107     name_pos += 1;
108   }
109   const char* name = line + name_pos;
110   size_t name_len = strlen(name);
111   if (name_len && name[name_len - 1] == '\n') {
112     name_len -= 1;
113   }
114 
115   backtrace_map_info_t* mi = calloc(1, sizeof(backtrace_map_info_t) + name_len + 1);
116   if (mi) {
117     mi->start = start;
118     mi->end = end;
119     mi->is_readable = strlen(permissions) == 4 && permissions[0] == 'r';
120     mi->is_writable = strlen(permissions) == 4 && permissions[1] == 'w';
121     mi->is_executable = strlen(permissions) == 4 && permissions[2] == 'x';
122     memcpy(mi->name, name, name_len);
123     mi->name[name_len] = '\0';
124     ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
125           "is_readable=%d, is_writable=%d, is_executable=%d, name=%s",
126           mi->start, mi->end,
127           mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
128   }
129   return mi;
130 }
131 
backtrace_create_map_info_list(pid_t tid)132 backtrace_map_info_t* backtrace_create_map_info_list(pid_t tid) {
133   char path[PATH_MAX];
134   char line[1024];
135   FILE* fp;
136   backtrace_map_info_t* milist = NULL;
137 
138   if (tid < 0) {
139     tid = getpid();
140   }
141   snprintf(path, PATH_MAX, "/proc/%d/maps", tid);
142   fp = fopen(path, "r");
143   if (fp) {
144     while(fgets(line, sizeof(line), fp)) {
145       backtrace_map_info_t* mi = parse_maps_line(line);
146       if (mi) {
147         mi->next = milist;
148         milist = mi;
149       }
150     }
151     fclose(fp);
152   }
153   return milist;
154 }
155 
156 #endif
157 
backtrace_destroy_map_info_list(backtrace_map_info_t * milist)158 void backtrace_destroy_map_info_list(backtrace_map_info_t* milist) {
159   while (milist) {
160     backtrace_map_info_t* next = milist->next;
161     free(milist);
162     milist = next;
163   }
164 }
165 
backtrace_find_map_info(const backtrace_map_info_t * milist,uintptr_t addr)166 const backtrace_map_info_t* backtrace_find_map_info(
167     const backtrace_map_info_t* milist, uintptr_t addr) {
168   const backtrace_map_info_t* mi = milist;
169   while (mi && !(addr >= mi->start && addr < mi->end)) {
170     mi = mi->next;
171   }
172   return mi;
173 }
174