1 /*
2 * Copyright (C) 2023 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 <unistd.h>
18
19 #include <cstddef>
20 #include <cstdio>
21 #include <string>
22 #include <tuple>
23
24 #include "berberis/base/bit_util.h"
25 #include "berberis/base/checks.h"
26 #include "berberis/base/macros.h"
27 #include "berberis/guest_state/guest_addr.h"
28 #include "berberis/guest_state/guest_state.h"
29 #include "berberis/runtime/execute_guest.h"
30 #include "berberis/tiny_loader/loaded_elf_file.h"
31 #include "berberis/tiny_loader/tiny_loader.h"
32
33 namespace berberis {
34
35 namespace {
36
Usage(const char * argv_0)37 void Usage(const char* argv_0) {
38 printf(
39 "Usage: %s [-h] [-a start_addr] guest_executable [arg1 [arg2 ...]]\n"
40 " -h - print this message\n"
41 " -a start_addr - start execution at start_addr\n"
42 " guest_executable - path to the guest executable\n",
43 argv_0);
44 }
45
ParseGuestAddr(const char * addr_cstr)46 std::tuple<GuestAddr, bool> ParseGuestAddr(const char* addr_cstr) {
47 char* end_ptr = nullptr;
48 errno = 0;
49 GuestAddr addr = bit_cast<GuestAddr>(strtoull(addr_cstr, &end_ptr, 16));
50
51 // Warning: setting errno on failure is implementation defined. So we also use extra heuristics.
52 if (errno != 0 || (*end_ptr != '\n' && *end_ptr != '\0')) {
53 printf("Cannot convert \"%s\" to integer: %s\n", addr_cstr,
54 errno != 0 ? strerror(errno) : "unexpected end of string");
55 return {kNullGuestAddr, false};
56 }
57 return {addr, true};
58 }
59
60 struct Options {
61 const char* guest_executable;
62 GuestAddr start_addr;
63 bool print_help_and_exit;
64 };
65
ParseArgs(int argc,char * argv[])66 Options ParseArgs(int argc, char* argv[]) {
67 CHECK_GE(argc, 1);
68
69 Options opts{};
70
71 while (true) {
72 int c = getopt(argc, argv, "ha:");
73 if (c < 0) {
74 break;
75 }
76 switch (c) {
77 case 'a': {
78 auto [addr, success] = ParseGuestAddr(optarg);
79 if (!success) {
80 return Options{.print_help_and_exit = true};
81 }
82 opts.start_addr = addr;
83 break;
84 }
85 case 'h':
86 return Options{.print_help_and_exit = true};
87 default:
88 UNREACHABLE();
89 }
90 }
91
92 if (optind >= argc) {
93 return Options{.print_help_and_exit = true};
94 }
95
96 opts.guest_executable = argv[optind];
97 opts.print_help_and_exit = false;
98 return opts;
99 }
100
101 } // namespace
102
103 } // namespace berberis
104
main(int argc,char * argv[])105 int main(int argc, char* argv[]) {
106 berberis::Options opts = berberis::ParseArgs(argc, argv);
107
108 if (opts.print_help_and_exit) {
109 berberis::Usage(argv[0]);
110 return -1;
111 }
112
113 LoadedElfFile elf_file;
114 std::string error_msg;
115 if (!TinyLoader::LoadFromFile(opts.guest_executable, &elf_file, &error_msg)) {
116 printf("%s\n", error_msg.c_str());
117 return -1;
118 }
119
120 berberis::ThreadState state{};
121 state.cpu.insn_addr = opts.start_addr;
122 ExecuteGuest(&state, berberis::kNullGuestAddr);
123
124 return 0;
125 }
126