Mercurial > hg > truffle
comparison src/os/aix/vm/attachListener_aix.cpp @ 14415:666e6ce3976c
8023038: PPC64 (part 15): Platform files for AIX/PPC64 support
Reviewed-by: kvn
author | simonis |
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date | Fri, 06 Sep 2013 20:16:09 +0200 |
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1 /* | |
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved. | |
3 * Copyright 2012, 2013 SAP AG. All rights reserved. | |
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
5 * | |
6 * This code is free software; you can redistribute it and/or modify it | |
7 * under the terms of the GNU General Public License version 2 only, as | |
8 * published by the Free Software Foundation. | |
9 * | |
10 * This code is distributed in the hope that it will be useful, but WITHOUT | |
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
13 * version 2 for more details (a copy is included in the LICENSE file that | |
14 * accompanied this code). | |
15 * | |
16 * You should have received a copy of the GNU General Public License version | |
17 * 2 along with this work; if not, write to the Free Software Foundation, | |
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
19 * | |
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
21 * or visit www.oracle.com if you need additional information or have any | |
22 * questions. | |
23 * | |
24 */ | |
25 | |
26 #include "precompiled.hpp" | |
27 #include "runtime/interfaceSupport.hpp" | |
28 #include "runtime/os.hpp" | |
29 #include "services/attachListener.hpp" | |
30 #include "services/dtraceAttacher.hpp" | |
31 | |
32 #include <unistd.h> | |
33 #include <signal.h> | |
34 #include <sys/types.h> | |
35 #include <sys/socket.h> | |
36 #include <sys/un.h> | |
37 #include <sys/stat.h> | |
38 | |
39 #ifndef UNIX_PATH_MAX | |
40 #define UNIX_PATH_MAX sizeof(((struct sockaddr_un *)0)->sun_path) | |
41 #endif | |
42 | |
43 // The attach mechanism on Linux uses a UNIX domain socket. An attach listener | |
44 // thread is created at startup or is created on-demand via a signal from | |
45 // the client tool. The attach listener creates a socket and binds it to a file | |
46 // in the filesystem. The attach listener then acts as a simple (single- | |
47 // threaded) server - it waits for a client to connect, reads the request, | |
48 // executes it, and returns the response to the client via the socket | |
49 // connection. | |
50 // | |
51 // As the socket is a UNIX domain socket it means that only clients on the | |
52 // local machine can connect. In addition there are two other aspects to | |
53 // the security: | |
54 // 1. The well known file that the socket is bound to has permission 400 | |
55 // 2. When a client connect, the SO_PEERID socket option is used to | |
56 // obtain the credentials of client. We check that the effective uid | |
57 // of the client matches this process. | |
58 | |
59 // forward reference | |
60 class AixAttachOperation; | |
61 | |
62 class AixAttachListener: AllStatic { | |
63 private: | |
64 // the path to which we bind the UNIX domain socket | |
65 static char _path[UNIX_PATH_MAX]; | |
66 static bool _has_path; | |
67 // Shutdown marker to prevent accept blocking during clean-up. | |
68 static bool _shutdown; | |
69 | |
70 // the file descriptor for the listening socket | |
71 static int _listener; | |
72 | |
73 static void set_path(char* path) { | |
74 if (path == NULL) { | |
75 _has_path = false; | |
76 } else { | |
77 strncpy(_path, path, UNIX_PATH_MAX); | |
78 _path[UNIX_PATH_MAX-1] = '\0'; | |
79 _has_path = true; | |
80 } | |
81 } | |
82 | |
83 static void set_listener(int s) { _listener = s; } | |
84 | |
85 // reads a request from the given connected socket | |
86 static AixAttachOperation* read_request(int s); | |
87 | |
88 public: | |
89 enum { | |
90 ATTACH_PROTOCOL_VER = 1 // protocol version | |
91 }; | |
92 enum { | |
93 ATTACH_ERROR_BADVERSION = 101 // error codes | |
94 }; | |
95 | |
96 // initialize the listener, returns 0 if okay | |
97 static int init(); | |
98 | |
99 static char* path() { return _path; } | |
100 static bool has_path() { return _has_path; } | |
101 static int listener() { return _listener; } | |
102 // Shutdown marker to prevent accept blocking during clean-up | |
103 static void set_shutdown(bool shutdown) { _shutdown = shutdown; } | |
104 static bool is_shutdown() { return _shutdown; } | |
105 | |
106 // write the given buffer to a socket | |
107 static int write_fully(int s, char* buf, int len); | |
108 | |
109 static AixAttachOperation* dequeue(); | |
110 }; | |
111 | |
112 class AixAttachOperation: public AttachOperation { | |
113 private: | |
114 // the connection to the client | |
115 int _socket; | |
116 | |
117 public: | |
118 void complete(jint res, bufferedStream* st); | |
119 | |
120 void set_socket(int s) { _socket = s; } | |
121 int socket() const { return _socket; } | |
122 | |
123 AixAttachOperation(char* name) : AttachOperation(name) { | |
124 set_socket(-1); | |
125 } | |
126 }; | |
127 | |
128 // statics | |
129 char AixAttachListener::_path[UNIX_PATH_MAX]; | |
130 bool AixAttachListener::_has_path; | |
131 int AixAttachListener::_listener = -1; | |
132 // Shutdown marker to prevent accept blocking during clean-up | |
133 bool AixAttachListener::_shutdown = false; | |
134 | |
135 // Supporting class to help split a buffer into individual components | |
136 class ArgumentIterator : public StackObj { | |
137 private: | |
138 char* _pos; | |
139 char* _end; | |
140 public: | |
141 ArgumentIterator(char* arg_buffer, size_t arg_size) { | |
142 _pos = arg_buffer; | |
143 _end = _pos + arg_size - 1; | |
144 } | |
145 char* next() { | |
146 if (*_pos == '\0') { | |
147 return NULL; | |
148 } | |
149 char* res = _pos; | |
150 char* next_pos = strchr(_pos, '\0'); | |
151 if (next_pos < _end) { | |
152 next_pos++; | |
153 } | |
154 _pos = next_pos; | |
155 return res; | |
156 } | |
157 }; | |
158 | |
159 // On AIX if sockets block until all data has been transmitted | |
160 // successfully in some communication domains a socket "close" may | |
161 // never complete. We have to take care that after the socket shutdown | |
162 // the listener never enters accept state. | |
163 | |
164 // atexit hook to stop listener and unlink the file that it is | |
165 // bound too. | |
166 | |
167 // Some modifications to the listener logic to prevent deadlocks on exit. | |
168 // 1. We Shutdown the socket here instead. AixAttachOperation::complete() is not the right place | |
169 // since more than one agent in a sequence in JPLIS live tests wouldn't work (Listener thread | |
170 // would be dead after the first operation completion). | |
171 // 2. close(s) may never return if the listener thread is in socket accept(). Unlinking the file | |
172 // should be sufficient for cleanup. | |
173 extern "C" { | |
174 static void listener_cleanup() { | |
175 static int cleanup_done; | |
176 if (!cleanup_done) { | |
177 cleanup_done = 1; | |
178 AixAttachListener::set_shutdown(true); | |
179 int s = AixAttachListener::listener(); | |
180 if (s != -1) { | |
181 ::shutdown(s, 2); | |
182 } | |
183 if (AixAttachListener::has_path()) { | |
184 ::unlink(AixAttachListener::path()); | |
185 } | |
186 } | |
187 } | |
188 } | |
189 | |
190 // Initialization - create a listener socket and bind it to a file | |
191 | |
192 int AixAttachListener::init() { | |
193 char path[UNIX_PATH_MAX]; // socket file | |
194 char initial_path[UNIX_PATH_MAX]; // socket file during setup | |
195 int listener; // listener socket (file descriptor) | |
196 | |
197 // register function to cleanup | |
198 ::atexit(listener_cleanup); | |
199 | |
200 int n = snprintf(path, UNIX_PATH_MAX, "%s/.java_pid%d", | |
201 os::get_temp_directory(), os::current_process_id()); | |
202 if (n < (int)UNIX_PATH_MAX) { | |
203 n = snprintf(initial_path, UNIX_PATH_MAX, "%s.tmp", path); | |
204 } | |
205 if (n >= (int)UNIX_PATH_MAX) { | |
206 return -1; | |
207 } | |
208 | |
209 // create the listener socket | |
210 listener = ::socket(PF_UNIX, SOCK_STREAM, 0); | |
211 if (listener == -1) { | |
212 return -1; | |
213 } | |
214 | |
215 // bind socket | |
216 struct sockaddr_un addr; | |
217 addr.sun_family = AF_UNIX; | |
218 strcpy(addr.sun_path, initial_path); | |
219 ::unlink(initial_path); | |
220 // We must call bind with the actual socketaddr length. This is obligatory for AS400. | |
221 int res = ::bind(listener, (struct sockaddr*)&addr, SUN_LEN(&addr)); | |
222 if (res == -1) { | |
223 RESTARTABLE(::close(listener), res); | |
224 return -1; | |
225 } | |
226 | |
227 // put in listen mode, set permissions, and rename into place | |
228 res = ::listen(listener, 5); | |
229 if (res == 0) { | |
230 RESTARTABLE(::chmod(initial_path, (S_IREAD|S_IWRITE) & ~(S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)), res); | |
231 if (res == 0) { | |
232 res = ::rename(initial_path, path); | |
233 } | |
234 } | |
235 if (res == -1) { | |
236 RESTARTABLE(::close(listener), res); | |
237 ::unlink(initial_path); | |
238 return -1; | |
239 } | |
240 set_path(path); | |
241 set_listener(listener); | |
242 set_shutdown(false); | |
243 | |
244 return 0; | |
245 } | |
246 | |
247 // Given a socket that is connected to a peer we read the request and | |
248 // create an AttachOperation. As the socket is blocking there is potential | |
249 // for a denial-of-service if the peer does not response. However this happens | |
250 // after the peer credentials have been checked and in the worst case it just | |
251 // means that the attach listener thread is blocked. | |
252 // | |
253 AixAttachOperation* AixAttachListener::read_request(int s) { | |
254 char ver_str[8]; | |
255 sprintf(ver_str, "%d", ATTACH_PROTOCOL_VER); | |
256 | |
257 // The request is a sequence of strings so we first figure out the | |
258 // expected count and the maximum possible length of the request. | |
259 // The request is: | |
260 // <ver>0<cmd>0<arg>0<arg>0<arg>0 | |
261 // where <ver> is the protocol version (1), <cmd> is the command | |
262 // name ("load", "datadump", ...), and <arg> is an argument | |
263 int expected_str_count = 2 + AttachOperation::arg_count_max; | |
264 const int max_len = (sizeof(ver_str) + 1) + (AttachOperation::name_length_max + 1) + | |
265 AttachOperation::arg_count_max*(AttachOperation::arg_length_max + 1); | |
266 | |
267 char buf[max_len]; | |
268 int str_count = 0; | |
269 | |
270 // Read until all (expected) strings have been read, the buffer is | |
271 // full, or EOF. | |
272 | |
273 int off = 0; | |
274 int left = max_len; | |
275 | |
276 do { | |
277 int n; | |
278 // Don't block on interrupts because this will | |
279 // hang in the clean-up when shutting down. | |
280 n = read(s, buf+off, left); | |
281 if (n == -1) { | |
282 return NULL; // reset by peer or other error | |
283 } | |
284 if (n == 0) { // end of file reached | |
285 break; | |
286 } | |
287 for (int i=0; i<n; i++) { | |
288 if (buf[off+i] == 0) { | |
289 // EOS found | |
290 str_count++; | |
291 | |
292 // The first string is <ver> so check it now to | |
293 // check for protocol mis-match | |
294 if (str_count == 1) { | |
295 if ((strlen(buf) != strlen(ver_str)) || | |
296 (atoi(buf) != ATTACH_PROTOCOL_VER)) { | |
297 char msg[32]; | |
298 sprintf(msg, "%d\n", ATTACH_ERROR_BADVERSION); | |
299 write_fully(s, msg, strlen(msg)); | |
300 return NULL; | |
301 } | |
302 } | |
303 } | |
304 } | |
305 off += n; | |
306 left -= n; | |
307 } while (left > 0 && str_count < expected_str_count); | |
308 | |
309 if (str_count != expected_str_count) { | |
310 return NULL; // incomplete request | |
311 } | |
312 | |
313 // parse request | |
314 | |
315 ArgumentIterator args(buf, (max_len)-left); | |
316 | |
317 // version already checked | |
318 char* v = args.next(); | |
319 | |
320 char* name = args.next(); | |
321 if (name == NULL || strlen(name) > AttachOperation::name_length_max) { | |
322 return NULL; | |
323 } | |
324 | |
325 AixAttachOperation* op = new AixAttachOperation(name); | |
326 | |
327 for (int i=0; i<AttachOperation::arg_count_max; i++) { | |
328 char* arg = args.next(); | |
329 if (arg == NULL) { | |
330 op->set_arg(i, NULL); | |
331 } else { | |
332 if (strlen(arg) > AttachOperation::arg_length_max) { | |
333 delete op; | |
334 return NULL; | |
335 } | |
336 op->set_arg(i, arg); | |
337 } | |
338 } | |
339 | |
340 op->set_socket(s); | |
341 return op; | |
342 } | |
343 | |
344 | |
345 // Dequeue an operation | |
346 // | |
347 // In the Linux implementation there is only a single operation and clients | |
348 // cannot queue commands (except at the socket level). | |
349 // | |
350 AixAttachOperation* AixAttachListener::dequeue() { | |
351 for (;;) { | |
352 int s; | |
353 | |
354 // wait for client to connect | |
355 struct sockaddr addr; | |
356 socklen_t len = sizeof(addr); | |
357 memset(&addr, 0, len); | |
358 // We must prevent accept blocking on the socket if it has been shut down. | |
359 // Therefore we allow interrups and check whether we have been shut down already. | |
360 if (AixAttachListener::is_shutdown()) { | |
361 return NULL; | |
362 } | |
363 s=::accept(listener(), &addr, &len); | |
364 if (s == -1) { | |
365 return NULL; // log a warning? | |
366 } | |
367 | |
368 // Added timeouts for read and write. If we get no request within the | |
369 // next AttachListenerTimeout milliseconds we just finish the connection. | |
370 struct timeval tv; | |
371 tv.tv_sec = 0; | |
372 tv.tv_usec = AttachListenerTimeout * 1000; | |
373 ::setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, (char*)&tv, sizeof(tv)); | |
374 ::setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, (char*)&tv, sizeof(tv)); | |
375 | |
376 // get the credentials of the peer and check the effective uid/guid | |
377 // - check with jeff on this. | |
378 struct peercred_struct cred_info; | |
379 socklen_t optlen = sizeof(cred_info); | |
380 if (::getsockopt(s, SOL_SOCKET, SO_PEERID, (void*)&cred_info, &optlen) == -1) { | |
381 int res; | |
382 RESTARTABLE(::close(s), res); | |
383 continue; | |
384 } | |
385 uid_t euid = geteuid(); | |
386 gid_t egid = getegid(); | |
387 | |
388 if (cred_info.euid != euid || cred_info.egid != egid) { | |
389 int res; | |
390 RESTARTABLE(::close(s), res); | |
391 continue; | |
392 } | |
393 | |
394 // peer credential look okay so we read the request | |
395 AixAttachOperation* op = read_request(s); | |
396 if (op == NULL) { | |
397 int res; | |
398 RESTARTABLE(::close(s), res); | |
399 continue; | |
400 } else { | |
401 return op; | |
402 } | |
403 } | |
404 } | |
405 | |
406 // write the given buffer to the socket | |
407 int AixAttachListener::write_fully(int s, char* buf, int len) { | |
408 do { | |
409 int n = ::write(s, buf, len); | |
410 if (n == -1) { | |
411 if (errno != EINTR) return -1; | |
412 } else { | |
413 buf += n; | |
414 len -= n; | |
415 } | |
416 } | |
417 while (len > 0); | |
418 return 0; | |
419 } | |
420 | |
421 // Complete an operation by sending the operation result and any result | |
422 // output to the client. At this time the socket is in blocking mode so | |
423 // potentially we can block if there is a lot of data and the client is | |
424 // non-responsive. For most operations this is a non-issue because the | |
425 // default send buffer is sufficient to buffer everything. In the future | |
426 // if there are operations that involves a very big reply then it the | |
427 // socket could be made non-blocking and a timeout could be used. | |
428 | |
429 void AixAttachOperation::complete(jint result, bufferedStream* st) { | |
430 JavaThread* thread = JavaThread::current(); | |
431 ThreadBlockInVM tbivm(thread); | |
432 | |
433 thread->set_suspend_equivalent(); | |
434 // cleared by handle_special_suspend_equivalent_condition() or | |
435 // java_suspend_self() via check_and_wait_while_suspended() | |
436 | |
437 // write operation result | |
438 char msg[32]; | |
439 sprintf(msg, "%d\n", result); | |
440 int rc = AixAttachListener::write_fully(this->socket(), msg, strlen(msg)); | |
441 | |
442 // write any result data | |
443 if (rc == 0) { | |
444 // Shutdown the socket in the cleanup function to enable more than | |
445 // one agent attach in a sequence (see comments to listener_cleanup()). | |
446 AixAttachListener::write_fully(this->socket(), (char*) st->base(), st->size()); | |
447 } | |
448 | |
449 // done | |
450 RESTARTABLE(::close(this->socket()), rc); | |
451 | |
452 // were we externally suspended while we were waiting? | |
453 thread->check_and_wait_while_suspended(); | |
454 | |
455 delete this; | |
456 } | |
457 | |
458 | |
459 // AttachListener functions | |
460 | |
461 AttachOperation* AttachListener::dequeue() { | |
462 JavaThread* thread = JavaThread::current(); | |
463 ThreadBlockInVM tbivm(thread); | |
464 | |
465 thread->set_suspend_equivalent(); | |
466 // cleared by handle_special_suspend_equivalent_condition() or | |
467 // java_suspend_self() via check_and_wait_while_suspended() | |
468 | |
469 AttachOperation* op = AixAttachListener::dequeue(); | |
470 | |
471 // were we externally suspended while we were waiting? | |
472 thread->check_and_wait_while_suspended(); | |
473 | |
474 return op; | |
475 } | |
476 | |
477 // Performs initialization at vm startup | |
478 // For AIX we remove any stale .java_pid file which could cause | |
479 // an attaching process to think we are ready to receive on the | |
480 // domain socket before we are properly initialized | |
481 | |
482 void AttachListener::vm_start() { | |
483 char fn[UNIX_PATH_MAX]; | |
484 struct stat64 st; | |
485 int ret; | |
486 | |
487 int n = snprintf(fn, UNIX_PATH_MAX, "%s/.java_pid%d", | |
488 os::get_temp_directory(), os::current_process_id()); | |
489 assert(n < (int)UNIX_PATH_MAX, "java_pid file name buffer overflow"); | |
490 | |
491 RESTARTABLE(::stat64(fn, &st), ret); | |
492 if (ret == 0) { | |
493 ret = ::unlink(fn); | |
494 if (ret == -1) { | |
495 debug_only(warning("failed to remove stale attach pid file at %s", fn)); | |
496 } | |
497 } | |
498 } | |
499 | |
500 int AttachListener::pd_init() { | |
501 JavaThread* thread = JavaThread::current(); | |
502 ThreadBlockInVM tbivm(thread); | |
503 | |
504 thread->set_suspend_equivalent(); | |
505 // cleared by handle_special_suspend_equivalent_condition() or | |
506 // java_suspend_self() via check_and_wait_while_suspended() | |
507 | |
508 int ret_code = AixAttachListener::init(); | |
509 | |
510 // were we externally suspended while we were waiting? | |
511 thread->check_and_wait_while_suspended(); | |
512 | |
513 return ret_code; | |
514 } | |
515 | |
516 // Attach Listener is started lazily except in the case when | |
517 // +ReduseSignalUsage is used | |
518 bool AttachListener::init_at_startup() { | |
519 if (ReduceSignalUsage) { | |
520 return true; | |
521 } else { | |
522 return false; | |
523 } | |
524 } | |
525 | |
526 // If the file .attach_pid<pid> exists in the working directory | |
527 // or /tmp then this is the trigger to start the attach mechanism | |
528 bool AttachListener::is_init_trigger() { | |
529 if (init_at_startup() || is_initialized()) { | |
530 return false; // initialized at startup or already initialized | |
531 } | |
532 char fn[PATH_MAX+1]; | |
533 sprintf(fn, ".attach_pid%d", os::current_process_id()); | |
534 int ret; | |
535 struct stat64 st; | |
536 RESTARTABLE(::stat64(fn, &st), ret); | |
537 if (ret == -1) { | |
538 snprintf(fn, sizeof(fn), "%s/.attach_pid%d", | |
539 os::get_temp_directory(), os::current_process_id()); | |
540 RESTARTABLE(::stat64(fn, &st), ret); | |
541 } | |
542 if (ret == 0) { | |
543 // simple check to avoid starting the attach mechanism when | |
544 // a bogus user creates the file | |
545 if (st.st_uid == geteuid()) { | |
546 init(); | |
547 return true; | |
548 } | |
549 } | |
550 return false; | |
551 } | |
552 | |
553 // if VM aborts then remove listener | |
554 void AttachListener::abort() { | |
555 listener_cleanup(); | |
556 } | |
557 | |
558 void AttachListener::pd_data_dump() { | |
559 os::signal_notify(SIGQUIT); | |
560 } | |
561 | |
562 AttachOperationFunctionInfo* AttachListener::pd_find_operation(const char* n) { | |
563 return NULL; | |
564 } | |
565 | |
566 jint AttachListener::pd_set_flag(AttachOperation* op, outputStream* out) { | |
567 out->print_cr("flag '%s' cannot be changed", op->arg(0)); | |
568 return JNI_ERR; | |
569 } | |
570 | |
571 void AttachListener::pd_detachall() { | |
572 // Cleanup server socket to detach clients. | |
573 listener_cleanup(); | |
574 } |