1 #include <elf.h>
2 #include <fcntl.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <sys/stat.h>
6 #include <sys/types.h>
7 #include <unistd.h>
8
9 #include <string>
10
usage(const char * me)11 void usage(const char* me) {
12 static const char* usage_s = "Usage:\n"
13 " %s /system/bin/app_process <args>\n"
14 "or, better:\n"
15 " setprop wrap.<nicename> %s\n";
16 fprintf(stderr, usage_s, me, me);
17 exit(1);
18 }
19
env_prepend(const char * name,const char * value,const char * delim)20 void env_prepend(const char* name, const char* value, const char* delim) {
21 const char* value_old = getenv(name);
22 std::string value_new = value;
23 if (value_old) {
24 value_new += delim;
25 value_new += value_old;
26 }
27 setenv(name, value_new.c_str(), 1);
28 }
29
elf_is_64bit(const char * path)30 bool elf_is_64bit(const char* path) {
31 int fd = open(path, O_RDONLY);
32 if (fd == -1) return false;
33
34 const size_t kBufSize = EI_CLASS + 1;
35 char buf[kBufSize];
36 ssize_t sz = read(fd, buf, kBufSize);
37 if (sz != kBufSize) {
38 close(fd);
39 return false;
40 }
41
42 if (buf[EI_MAG0] != ELFMAG0 || buf[EI_MAG1] != ELFMAG1 ||
43 buf[EI_MAG2] != ELFMAG2 || buf[EI_MAG3] != ELFMAG3)
44 return false;
45
46 bool is_64bit = buf[EI_CLASS] == ELFCLASS64;
47 close(fd);
48 return is_64bit;
49 }
50
main(int argc,char ** argv)51 int main(int argc, char** argv) {
52 if (argc < 2) {
53 usage(argv[0]);
54 }
55 char** args = new char*[argc];
56 // If we are wrapping app_process, replace it with app_process_asan.
57 // TODO(eugenis): rewrite to <dirname>/asan/<basename>, if exists?
58 if (strcmp(argv[1], "/system/bin/app_process") == 0) {
59 args[0] = (char*)"/system/bin/asan/app_process";
60 } else if (strcmp(argv[1], "/system/bin/app_process32") == 0) {
61 args[0] = (char*)"/system/bin/asan/app_process32";
62 } else if (strcmp(argv[1], "/system/bin/app_process64") == 0) {
63 args[0] = (char*)"/system/bin/asan/app_process64";
64 } else {
65 args[0] = argv[1];
66 }
67
68 for (int i = 1; i < argc - 1; ++i)
69 args[i] = argv[i + 1];
70 args[argc - 1] = 0;
71
72 if (elf_is_64bit(args[0])) {
73 env_prepend("LD_LIBRARY_PATH", "/system/lib64/asan:/system/lib64", ":");
74 } else {
75 env_prepend("LD_LIBRARY_PATH", "/system/lib/asan:/system/lib", ":");
76 }
77 env_prepend("ASAN_OPTIONS", "allow_user_segv_handler=1", ",");
78
79 printf("ASAN_OPTIONS: %s\n", getenv("ASAN_OPTIONS"));
80 printf("LD_LIBRARY_PATH: %s\n", getenv("LD_LIBRARY_PATH"));
81 for (int i = 0; i < argc - 1; ++i)
82 printf("argv[%d] = %s\n", i, args[i]);
83
84 execv(args[0], args);
85 }
86