1 #include <atomic>
2 #include <cassert>
3 #include <chrono>
4 #include <cstdlib>
5 #include <cstring>
6 #include <errno.h>
7 #include <future>
8 #include <inttypes.h>
9 #include <memory>
10 #include <mutex>
11 #if !defined(_WIN32)
12 #include <pthread.h>
13 #include <signal.h>
14 #include <unistd.h>
15 #endif
16 #include "thread.h"
17 #include <setjmp.h>
18 #include <stdint.h>
19 #include <stdio.h>
20 #include <string.h>
21 #include <string>
22 #include <thread>
23 #include <time.h>
24 #include <vector>
25 #if defined(__APPLE__)
26 #include <TargetConditionals.h>
27 #endif
28
29 static const char *const PRINT_PID_COMMAND = "print-pid";
30
31 static bool g_print_thread_ids = false;
32 static std::mutex g_print_mutex;
33 static bool g_threads_do_segfault = false;
34
35 static std::mutex g_jump_buffer_mutex;
36 static jmp_buf g_jump_buffer;
37 static bool g_is_segfaulting = false;
38
39 static char g_message[256];
40
41 static volatile char g_c1 = '0';
42 static volatile char g_c2 = '1';
43
print_pid()44 static void print_pid() {
45 #if defined(_WIN32)
46 fprintf(stderr, "PID: %d\n", ::GetCurrentProcessId());
47 #else
48 fprintf(stderr, "PID: %d\n", getpid());
49 #endif
50 }
51
signal_handler(int signo)52 static void signal_handler(int signo) {
53 #if defined(_WIN32)
54 // No signal support on Windows.
55 #else
56 const char *signal_name = nullptr;
57 switch (signo) {
58 case SIGUSR1:
59 signal_name = "SIGUSR1";
60 break;
61 case SIGSEGV:
62 signal_name = "SIGSEGV";
63 break;
64 default:
65 signal_name = nullptr;
66 }
67
68 // Print notice that we received the signal on a given thread.
69 char buf[100];
70 if (signal_name)
71 snprintf(buf, sizeof(buf), "received %s on thread id: %" PRIx64 "\n", signal_name, get_thread_id());
72 else
73 snprintf(buf, sizeof(buf), "received signo %d (%s) on thread id: %" PRIx64 "\n", signo, strsignal(signo), get_thread_id());
74 write(STDOUT_FILENO, buf, strlen(buf));
75
76 // Reset the signal handler if we're one of the expected signal handlers.
77 switch (signo) {
78 case SIGSEGV:
79 if (g_is_segfaulting) {
80 // Fix up the pointer we're writing to. This needs to happen if nothing
81 // intercepts the SIGSEGV (i.e. if somebody runs this from the command
82 // line).
83 longjmp(g_jump_buffer, 1);
84 }
85 break;
86 case SIGUSR1:
87 if (g_is_segfaulting) {
88 // Fix up the pointer we're writing to. This is used to test gdb remote
89 // signal delivery. A SIGSEGV will be raised when the thread is created,
90 // switched out for a SIGUSR1, and then this code still needs to fix the
91 // seg fault. (i.e. if somebody runs this from the command line).
92 longjmp(g_jump_buffer, 1);
93 }
94 break;
95 }
96
97 // Reset the signal handler.
98 sig_t sig_result = signal(signo, signal_handler);
99 if (sig_result == SIG_ERR) {
100 fprintf(stderr, "failed to set signal handler: errno=%d\n", errno);
101 exit(1);
102 }
103 #endif
104 }
105
swap_chars()106 static void swap_chars() {
107 #if defined(__x86_64__) || defined(__i386__)
108 asm volatile("movb %1, (%2)\n\t"
109 "movb %0, (%3)\n\t"
110 "movb %0, (%2)\n\t"
111 "movb %1, (%3)\n\t"
112 :
113 : "i"('0'), "i"('1'), "r"(&g_c1), "r"(&g_c2)
114 : "memory");
115 #elif defined(__aarch64__)
116 asm volatile("strb %w1, [%2]\n\t"
117 "strb %w0, [%3]\n\t"
118 "strb %w0, [%2]\n\t"
119 "strb %w1, [%3]\n\t"
120 :
121 : "r"('0'), "r"('1'), "r"(&g_c1), "r"(&g_c2)
122 : "memory");
123 #elif defined(__arm__)
124 asm volatile("strb %1, [%2]\n\t"
125 "strb %0, [%3]\n\t"
126 "strb %0, [%2]\n\t"
127 "strb %1, [%3]\n\t"
128 :
129 : "r"('0'), "r"('1'), "r"(&g_c1), "r"(&g_c2)
130 : "memory");
131 #else
132 #warning This may generate unpredictible assembly and cause the single-stepping test to fail.
133 #warning Please add appropriate assembly for your target.
134 g_c1 = '1';
135 g_c2 = '0';
136
137 g_c1 = '0';
138 g_c2 = '1';
139 #endif
140 }
141
trap()142 static void trap() {
143 #if defined(__x86_64__) || defined(__i386__)
144 asm volatile("int3");
145 #elif defined(__aarch64__)
146 asm volatile("brk #0xf000");
147 #elif defined(__arm__)
148 asm volatile("udf #254");
149 #elif defined(__powerpc__)
150 asm volatile("trap");
151 #elif __has_builtin(__builtin_debugtrap())
152 __builtin_debugtrap();
153 #else
154 #warning Don't know how to generate a trap. Some tests may fail.
155 #endif
156 }
157
158 static void hello() {
159 std::lock_guard<std::mutex> lock(g_print_mutex);
160 printf("hello, world\n");
161 }
162
163 static void *thread_func(std::promise<void> ready) {
164 ready.set_value();
165 static std::atomic<int> s_thread_index(1);
166 const int this_thread_index = s_thread_index++;
167 if (g_print_thread_ids) {
168 std::lock_guard<std::mutex> lock(g_print_mutex);
169 printf("thread %d id: %" PRIx64 "\n", this_thread_index, get_thread_id());
170 }
171
172 if (g_threads_do_segfault) {
173 // Sleep for a number of seconds based on the thread index.
174 // TODO add ability to send commands to test exe so we can
175 // handle timing more precisely. This is clunky. All we're
176 // trying to do is add predictability as to the timing of
177 // signal generation by created threads.
178 int sleep_seconds = 2 * (this_thread_index - 1);
179 std::this_thread::sleep_for(std::chrono::seconds(sleep_seconds));
180
181 // Test creating a SEGV.
182 {
183 std::lock_guard<std::mutex> lock(g_jump_buffer_mutex);
184 g_is_segfaulting = true;
185 int *bad_p = nullptr;
186 if (setjmp(g_jump_buffer) == 0) {
187 // Force a seg fault signal on this thread.
188 *bad_p = 0;
189 } else {
190 // Tell the system we're no longer seg faulting.
191 // Used by the SIGUSR1 signal handler that we inject
192 // in place of the SIGSEGV so it only tries to
193 // recover from the SIGSEGV if this seg fault code
194 // was in play.
195 g_is_segfaulting = false;
196 }
197 }
198
199 {
200 std::lock_guard<std::mutex> lock(g_print_mutex);
201 printf("thread %" PRIx64 ": past SIGSEGV\n", get_thread_id());
202 }
203 }
204
205 int sleep_seconds_remaining = 60;
206 std::this_thread::sleep_for(std::chrono::seconds(sleep_seconds_remaining));
207
208 return nullptr;
209 }
210
consume_front(std::string & str,const std::string & front)211 static bool consume_front(std::string &str, const std::string &front) {
212 if (str.find(front) != 0)
213 return false;
214
215 str = str.substr(front.size());
216 return true;
217 }
218
main(int argc,char ** argv)219 int main(int argc, char **argv) {
220 lldb_enable_attach();
221
222 std::vector<std::thread> threads;
223 std::unique_ptr<uint8_t[]> heap_array_up;
224 int return_value = 0;
225
226 #if !defined(_WIN32)
227 bool is_child = false;
228
229 // Set the signal handler.
230 sig_t sig_result = signal(SIGALRM, signal_handler);
231 if (sig_result == SIG_ERR) {
232 fprintf(stderr, "failed to set SIGALRM signal handler: errno=%d\n", errno);
233 exit(1);
234 }
235
236 sig_result = signal(SIGUSR1, signal_handler);
237 if (sig_result == SIG_ERR) {
238 fprintf(stderr, "failed to set SIGUSR1 handler: errno=%d\n", errno);
239 exit(1);
240 }
241
242 sig_result = signal(SIGSEGV, signal_handler);
243 if (sig_result == SIG_ERR) {
244 fprintf(stderr, "failed to set SIGSEGV handler: errno=%d\n", errno);
245 exit(1);
246 }
247
248 sig_result = signal(SIGCHLD, SIG_IGN);
249 if (sig_result == SIG_ERR) {
250 fprintf(stderr, "failed to set SIGCHLD handler: errno=%d\n", errno);
251 exit(1);
252 }
253 #endif
254
255 // Process command line args.
256 for (int i = 1; i < argc; ++i) {
257 std::string arg = argv[i];
258 if (consume_front(arg, "stderr:")) {
259 // Treat remainder as text to go to stderr.
260 fprintf(stderr, "%s\n", arg.c_str());
261 } else if (consume_front(arg, "retval:")) {
262 // Treat as the return value for the program.
263 return_value = std::atoi(arg.c_str());
264 } else if (consume_front(arg, "sleep:")) {
265 // Treat as the amount of time to have this process sleep (in seconds).
266 int sleep_seconds_remaining = std::atoi(arg.c_str());
267
268 // Loop around, sleeping until all sleep time is used up. Note that
269 // signals will cause sleep to end early with the number of seconds
270 // remaining.
271 std::this_thread::sleep_for(
272 std::chrono::seconds(sleep_seconds_remaining));
273
274 } else if (consume_front(arg, "set-message:")) {
275 // Copy the contents after "set-message:" to the g_message buffer.
276 // Used for reading inferior memory and verifying contents match
277 // expectations.
278 strncpy(g_message, arg.c_str(), sizeof(g_message));
279
280 // Ensure we're null terminated.
281 g_message[sizeof(g_message) - 1] = '\0';
282
283 } else if (consume_front(arg, "print-message:")) {
284 std::lock_guard<std::mutex> lock(g_print_mutex);
285 printf("message: %s\n", g_message);
286 } else if (consume_front(arg, "get-data-address-hex:")) {
287 volatile void *data_p = nullptr;
288
289 if (arg == "g_message")
290 data_p = &g_message[0];
291 else if (arg == "g_c1")
292 data_p = &g_c1;
293 else if (arg == "g_c2")
294 data_p = &g_c2;
295
296 std::lock_guard<std::mutex> lock(g_print_mutex);
297 printf("data address: %p\n", data_p);
298 } else if (consume_front(arg, "get-heap-address-hex:")) {
299 // Create a byte array if not already present.
300 if (!heap_array_up)
301 heap_array_up.reset(new uint8_t[32]);
302
303 std::lock_guard<std::mutex> lock(g_print_mutex);
304 printf("heap address: %p\n", heap_array_up.get());
305
306 } else if (consume_front(arg, "get-stack-address-hex:")) {
307 std::lock_guard<std::mutex> lock(g_print_mutex);
308 printf("stack address: %p\n", &return_value);
309 } else if (consume_front(arg, "get-code-address-hex:")) {
310 void (*func_p)() = nullptr;
311
312 if (arg == "hello")
313 func_p = hello;
314 else if (arg == "swap_chars")
315 func_p = swap_chars;
316
317 std::lock_guard<std::mutex> lock(g_print_mutex);
318 printf("code address: %p\n", func_p);
319 } else if (consume_front(arg, "call-function:")) {
320 void (*func_p)() = nullptr;
321
322 if (arg == "hello")
323 func_p = hello;
324 else if (arg == "swap_chars")
325 func_p = swap_chars;
326 func_p();
327 #if !defined(_WIN32) && !defined(TARGET_OS_WATCH) && !defined(TARGET_OS_TV)
328 } else if (arg == "fork") {
329 pid_t fork_pid = fork();
330 assert(fork_pid != -1);
331 is_child = fork_pid == 0;
332 } else if (arg == "vfork") {
333 if (vfork() == 0)
334 _exit(0);
335 } else if (consume_front(arg, "process:sync:")) {
336 // this is only valid after fork
337 const char *filenames[] = {"parent", "child"};
338 std::string my_file = arg + "." + filenames[is_child];
339 std::string other_file = arg + "." + filenames[!is_child];
340
341 // indicate that we're ready
342 FILE *f = fopen(my_file.c_str(), "w");
343 assert(f);
344 fclose(f);
345
346 // wait for the other process to be ready
347 for (int i = 0; i < 5; ++i) {
348 f = fopen(other_file.c_str(), "r");
349 if (f)
350 break;
351 std::this_thread::sleep_for(std::chrono::milliseconds(125 * (1<<i)));
352 }
353 assert(f);
354 fclose(f);
355 #endif
356 } else if (consume_front(arg, "thread:new")) {
357 std::promise<void> promise;
358 std::future<void> ready = promise.get_future();
359 threads.push_back(std::thread(thread_func, std::move(promise)));
360 ready.wait();
361 } else if (consume_front(arg, "thread:print-ids")) {
362 // Turn on thread id announcing.
363 g_print_thread_ids = true;
364
365 // And announce us.
366 {
367 std::lock_guard<std::mutex> lock(g_print_mutex);
368 printf("thread 0 id: %" PRIx64 "\n", get_thread_id());
369 }
370 } else if (consume_front(arg, "thread:segfault")) {
371 g_threads_do_segfault = true;
372 } else if (consume_front(arg, "print-pid")) {
373 print_pid();
374 } else if (consume_front(arg, "print-env:")) {
375 // Print the value of specified envvar to stdout.
376 const char *value = getenv(arg.c_str());
377 printf("%s\n", value ? value : "__unset__");
378 } else if (consume_front(arg, "trap")) {
379 trap();
380 #if !defined(_WIN32)
381 } else if (arg == "stop") {
382 raise(SIGINT);
383 #endif
384 } else {
385 // Treat the argument as text for stdout.
386 printf("%s\n", argv[i]);
387 }
388 }
389
390 // If we launched any threads, join them
391 for (std::vector<std::thread>::iterator it = threads.begin();
392 it != threads.end(); ++it)
393 it->join();
394
395 return return_value;
396 }
397