Mercurial > hg > truffle
annotate src/os/linux/vm/attachListener_linux.cpp @ 1029:b0b36f0de97e
Merge
author | tonyp |
---|---|
date | Tue, 20 Oct 2009 11:28:25 -0700 |
parents | d1605aabd0a1 |
children | a2ea687fdc7c |
rev | line source |
---|---|
0 | 1 /* |
196 | 2 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_attachListener_linux.cpp.incl" | |
27 | |
28 #include <unistd.h> | |
29 #include <signal.h> | |
30 #include <sys/types.h> | |
31 #include <sys/socket.h> | |
32 #include <sys/un.h> | |
33 #include <sys/stat.h> | |
34 | |
35 // The attach mechanism on Linux uses a UNIX domain socket. An attach listener | |
36 // thread is created at startup or is created on-demand via a signal from | |
37 // the client tool. The attach listener creates a socket and binds it to a file | |
38 // in the filesystem. The attach listener then acts as a simple (single- | |
39 // threaded) server - tt waits for a client to connect, reads the request, | |
40 // executes it, and returns the response to the client via the socket | |
41 // connection. | |
42 // | |
43 // As the socket is a UNIX domain socket it means that only clients on the | |
44 // local machine can connect. In addition there are two other aspects to | |
45 // the security: | |
46 // 1. The well known file that the socket is bound to has permission 400 | |
47 // 2. When a client connect, the SO_PEERCRED socket option is used to | |
48 // obtain the credentials of client. We check that the effective uid | |
49 // of the client matches this process. | |
50 | |
51 // forward reference | |
52 class LinuxAttachOperation; | |
53 | |
54 class LinuxAttachListener: AllStatic { | |
55 private: | |
56 // the path to which we bind the UNIX domain socket | |
57 static char _path[PATH_MAX+1]; | |
58 static bool _has_path; | |
59 | |
60 // the file descriptor for the listening socket | |
61 static int _listener; | |
62 | |
63 static void set_path(char* path) { | |
64 if (path == NULL) { | |
65 _has_path = false; | |
66 } else { | |
67 strncpy(_path, path, PATH_MAX); | |
68 _path[PATH_MAX] = '\0'; | |
69 _has_path = true; | |
70 } | |
71 } | |
72 | |
73 static void set_listener(int s) { _listener = s; } | |
74 | |
75 // reads a request from the given connected socket | |
76 static LinuxAttachOperation* read_request(int s); | |
77 | |
78 public: | |
79 enum { | |
80 ATTACH_PROTOCOL_VER = 1 // protocol version | |
81 }; | |
82 enum { | |
83 ATTACH_ERROR_BADVERSION = 101 // error codes | |
84 }; | |
85 | |
86 // initialize the listener, returns 0 if okay | |
87 static int init(); | |
88 | |
89 static char* path() { return _path; } | |
90 static bool has_path() { return _has_path; } | |
91 static int listener() { return _listener; } | |
92 | |
93 // write the given buffer to a socket | |
94 static int write_fully(int s, char* buf, int len); | |
95 | |
96 static LinuxAttachOperation* dequeue(); | |
97 }; | |
98 | |
99 class LinuxAttachOperation: public AttachOperation { | |
100 private: | |
101 // the connection to the client | |
102 int _socket; | |
103 | |
104 public: | |
105 void complete(jint res, bufferedStream* st); | |
106 | |
107 void set_socket(int s) { _socket = s; } | |
108 int socket() const { return _socket; } | |
109 | |
110 LinuxAttachOperation(char* name) : AttachOperation(name) { | |
111 set_socket(-1); | |
112 } | |
113 }; | |
114 | |
115 // statics | |
116 char LinuxAttachListener::_path[PATH_MAX+1]; | |
117 bool LinuxAttachListener::_has_path; | |
118 int LinuxAttachListener::_listener = -1; | |
119 | |
120 // Supporting class to help split a buffer into individual components | |
121 class ArgumentIterator : public StackObj { | |
122 private: | |
123 char* _pos; | |
124 char* _end; | |
125 public: | |
126 ArgumentIterator(char* arg_buffer, size_t arg_size) { | |
127 _pos = arg_buffer; | |
128 _end = _pos + arg_size - 1; | |
129 } | |
130 char* next() { | |
131 if (*_pos == '\0') { | |
132 return NULL; | |
133 } | |
134 char* res = _pos; | |
135 char* next_pos = strchr(_pos, '\0'); | |
136 if (next_pos < _end) { | |
137 next_pos++; | |
138 } | |
139 _pos = next_pos; | |
140 return res; | |
141 } | |
142 }; | |
143 | |
144 | |
145 // atexit hook to stop listener and unlink the file that it is | |
146 // bound too. | |
147 extern "C" { | |
148 static void listener_cleanup() { | |
149 static int cleanup_done; | |
150 if (!cleanup_done) { | |
151 cleanup_done = 1; | |
152 int s = LinuxAttachListener::listener(); | |
153 if (s != -1) { | |
154 ::close(s); | |
155 } | |
156 if (LinuxAttachListener::has_path()) { | |
157 ::unlink(LinuxAttachListener::path()); | |
158 } | |
159 } | |
160 } | |
161 } | |
162 | |
163 // Initialization - create a listener socket and bind it to a file | |
164 | |
165 int LinuxAttachListener::init() { | |
166 char path[PATH_MAX+1]; // socket file | |
167 int listener; // listener socket (file descriptor) | |
168 | |
169 // register function to cleanup | |
170 ::atexit(listener_cleanup); | |
171 | |
172 // create the listener socket | |
173 listener = ::socket(PF_UNIX, SOCK_STREAM, 0); | |
174 if (listener == -1) { | |
175 return -1; | |
176 } | |
177 | |
178 int res = -1; | |
179 struct sockaddr_un addr; | |
180 addr.sun_family = AF_UNIX; | |
181 | |
182 // FIXME: Prior to b39 the tool-side API expected to find the well | |
183 // known file in the working directory. To allow this libjvm.so work with | |
184 // a pre-b39 SDK we create it in the working directory if | |
185 // +StartAttachListener is used is used. All unit tests for this feature | |
186 // currently used this flag. Once b39 SDK has been promoted we can remove | |
187 // this code. | |
188 if (StartAttachListener) { | |
189 sprintf(path, ".java_pid%d", os::current_process_id()); | |
190 strcpy(addr.sun_path, path); | |
191 ::unlink(path); | |
192 res = ::bind(listener, (struct sockaddr*)&addr, sizeof(addr)); | |
193 } | |
194 if (res == -1) { | |
195 sprintf(path, "%s/.java_pid%d", os::get_temp_directory(), os::current_process_id()); | |
196 strcpy(addr.sun_path, path); | |
197 ::unlink(path); | |
198 res = ::bind(listener, (struct sockaddr*)&addr, sizeof(addr)); | |
199 } | |
200 if (res == -1) { | |
201 RESTARTABLE(::close(listener), res); | |
202 return -1; | |
203 } | |
204 set_path(path); | |
205 | |
206 // put in listen mode and set permission | |
207 if ((::listen(listener, 5) == -1) || (::chmod(path, S_IREAD|S_IWRITE) == -1)) { | |
208 RESTARTABLE(::close(listener), res); | |
209 ::unlink(path); | |
210 set_path(NULL); | |
211 return -1; | |
212 } | |
213 set_listener(listener); | |
214 | |
215 return 0; | |
216 } | |
217 | |
218 // Given a socket that is connected to a peer we read the request and | |
219 // create an AttachOperation. As the socket is blocking there is potential | |
220 // for a denial-of-service if the peer does not response. However this happens | |
221 // after the peer credentials have been checked and in the worst case it just | |
222 // means that the attach listener thread is blocked. | |
223 // | |
224 LinuxAttachOperation* LinuxAttachListener::read_request(int s) { | |
225 char ver_str[8]; | |
226 sprintf(ver_str, "%d", ATTACH_PROTOCOL_VER); | |
227 | |
228 // The request is a sequence of strings so we first figure out the | |
229 // expected count and the maximum possible length of the request. | |
230 // The request is: | |
231 // <ver>0<cmd>0<arg>0<arg>0<arg>0 | |
232 // where <ver> is the protocol version (1), <cmd> is the command | |
233 // name ("load", "datadump", ...), and <arg> is an argument | |
234 int expected_str_count = 2 + AttachOperation::arg_count_max; | |
50
485d403e94e1
6452081: 3/4 Allow for Linux builds with Sun Studio Linux compilers
dcubed
parents:
0
diff
changeset
|
235 const int max_len = (sizeof(ver_str) + 1) + (AttachOperation::name_length_max + 1) + |
0 | 236 AttachOperation::arg_count_max*(AttachOperation::arg_length_max + 1); |
237 | |
238 char buf[max_len]; | |
239 int str_count = 0; | |
240 | |
241 // Read until all (expected) strings have been read, the buffer is | |
242 // full, or EOF. | |
243 | |
244 int off = 0; | |
245 int left = max_len; | |
246 | |
247 do { | |
248 int n; | |
249 RESTARTABLE(read(s, buf+off, left), n); | |
250 if (n == -1) { | |
251 return NULL; // reset by peer or other error | |
252 } | |
253 if (n == 0) { | |
254 break; | |
255 } | |
256 for (int i=0; i<n; i++) { | |
257 if (buf[off+i] == 0) { | |
258 // EOS found | |
259 str_count++; | |
260 | |
261 // The first string is <ver> so check it now to | |
262 // check for protocol mis-match | |
263 if (str_count == 1) { | |
264 if ((strlen(buf) != strlen(ver_str)) || | |
265 (atoi(buf) != ATTACH_PROTOCOL_VER)) { | |
266 char msg[32]; | |
267 sprintf(msg, "%d\n", ATTACH_ERROR_BADVERSION); | |
268 write_fully(s, msg, strlen(msg)); | |
269 return NULL; | |
270 } | |
271 } | |
272 } | |
273 } | |
274 off += n; | |
275 left -= n; | |
276 } while (left > 0 && str_count < expected_str_count); | |
277 | |
278 if (str_count != expected_str_count) { | |
279 return NULL; // incomplete request | |
280 } | |
281 | |
282 // parse request | |
283 | |
284 ArgumentIterator args(buf, (max_len)-left); | |
285 | |
286 // version already checked | |
287 char* v = args.next(); | |
288 | |
289 char* name = args.next(); | |
290 if (name == NULL || strlen(name) > AttachOperation::name_length_max) { | |
291 return NULL; | |
292 } | |
293 | |
294 LinuxAttachOperation* op = new LinuxAttachOperation(name); | |
295 | |
296 for (int i=0; i<AttachOperation::arg_count_max; i++) { | |
297 char* arg = args.next(); | |
298 if (arg == NULL) { | |
299 op->set_arg(i, NULL); | |
300 } else { | |
301 if (strlen(arg) > AttachOperation::arg_length_max) { | |
302 delete op; | |
303 return NULL; | |
304 } | |
305 op->set_arg(i, arg); | |
306 } | |
307 } | |
308 | |
309 op->set_socket(s); | |
310 return op; | |
311 } | |
312 | |
313 | |
314 // Dequeue an operation | |
315 // | |
316 // In the Linux implementation there is only a single operation and clients | |
317 // cannot queue commands (except at the socket level). | |
318 // | |
319 LinuxAttachOperation* LinuxAttachListener::dequeue() { | |
320 for (;;) { | |
321 int s; | |
322 | |
323 // wait for client to connect | |
324 struct sockaddr addr; | |
325 socklen_t len = sizeof(addr); | |
326 RESTARTABLE(::accept(listener(), &addr, &len), s); | |
327 if (s == -1) { | |
328 return NULL; // log a warning? | |
329 } | |
330 | |
331 // get the credentials of the peer and check the effective uid/guid | |
332 // - check with jeff on this. | |
333 struct ucred cred_info; | |
334 socklen_t optlen = sizeof(cred_info); | |
335 if (::getsockopt(s, SOL_SOCKET, SO_PEERCRED, (void*)&cred_info, &optlen) == -1) { | |
336 int res; | |
337 RESTARTABLE(::close(s), res); | |
338 continue; | |
339 } | |
340 uid_t euid = geteuid(); | |
341 gid_t egid = getegid(); | |
342 | |
343 if (cred_info.uid != euid || cred_info.gid != egid) { | |
344 int res; | |
345 RESTARTABLE(::close(s), res); | |
346 continue; | |
347 } | |
348 | |
349 // peer credential look okay so we read the request | |
350 LinuxAttachOperation* op = read_request(s); | |
351 if (op == NULL) { | |
352 int res; | |
353 RESTARTABLE(::close(s), res); | |
354 continue; | |
355 } else { | |
356 return op; | |
357 } | |
358 } | |
359 } | |
360 | |
361 // write the given buffer to the socket | |
362 int LinuxAttachListener::write_fully(int s, char* buf, int len) { | |
363 do { | |
364 int n = ::write(s, buf, len); | |
365 if (n == -1) { | |
366 if (errno != EINTR) return -1; | |
367 } else { | |
368 buf += n; | |
369 len -= n; | |
370 } | |
371 } | |
372 while (len > 0); | |
373 return 0; | |
374 } | |
375 | |
376 // Complete an operation by sending the operation result and any result | |
377 // output to the client. At this time the socket is in blocking mode so | |
378 // potentially we can block if there is a lot of data and the client is | |
379 // non-responsive. For most operations this is a non-issue because the | |
380 // default send buffer is sufficient to buffer everything. In the future | |
381 // if there are operations that involves a very big reply then it the | |
382 // socket could be made non-blocking and a timeout could be used. | |
383 | |
384 void LinuxAttachOperation::complete(jint result, bufferedStream* st) { | |
385 JavaThread* thread = JavaThread::current(); | |
386 ThreadBlockInVM tbivm(thread); | |
387 | |
388 thread->set_suspend_equivalent(); | |
389 // cleared by handle_special_suspend_equivalent_condition() or | |
390 // java_suspend_self() via check_and_wait_while_suspended() | |
391 | |
392 // write operation result | |
393 char msg[32]; | |
394 sprintf(msg, "%d\n", result); | |
395 int rc = LinuxAttachListener::write_fully(this->socket(), msg, strlen(msg)); | |
396 | |
397 // write any result data | |
398 if (rc == 0) { | |
399 LinuxAttachListener::write_fully(this->socket(), (char*) st->base(), st->size()); | |
400 ::shutdown(this->socket(), 2); | |
401 } | |
402 | |
403 // done | |
404 RESTARTABLE(::close(this->socket()), rc); | |
405 | |
406 // were we externally suspended while we were waiting? | |
407 thread->check_and_wait_while_suspended(); | |
408 | |
409 delete this; | |
410 } | |
411 | |
412 | |
413 // AttachListener functions | |
414 | |
415 AttachOperation* AttachListener::dequeue() { | |
416 JavaThread* thread = JavaThread::current(); | |
417 ThreadBlockInVM tbivm(thread); | |
418 | |
419 thread->set_suspend_equivalent(); | |
420 // cleared by handle_special_suspend_equivalent_condition() or | |
421 // java_suspend_self() via check_and_wait_while_suspended() | |
422 | |
423 AttachOperation* op = LinuxAttachListener::dequeue(); | |
424 | |
425 // were we externally suspended while we were waiting? | |
426 thread->check_and_wait_while_suspended(); | |
427 | |
428 return op; | |
429 } | |
430 | |
431 int AttachListener::pd_init() { | |
432 JavaThread* thread = JavaThread::current(); | |
433 ThreadBlockInVM tbivm(thread); | |
434 | |
435 thread->set_suspend_equivalent(); | |
436 // cleared by handle_special_suspend_equivalent_condition() or | |
437 // java_suspend_self() via check_and_wait_while_suspended() | |
438 | |
439 int ret_code = LinuxAttachListener::init(); | |
440 | |
441 // were we externally suspended while we were waiting? | |
442 thread->check_and_wait_while_suspended(); | |
443 | |
444 return ret_code; | |
445 } | |
446 | |
447 // Attach Listener is started lazily except in the case when | |
448 // +ReduseSignalUsage is used | |
449 bool AttachListener::init_at_startup() { | |
450 if (ReduceSignalUsage) { | |
451 return true; | |
452 } else { | |
453 return false; | |
454 } | |
455 } | |
456 | |
457 // If the file .attach_pid<pid> exists in the working directory | |
458 // or /tmp then this is the trigger to start the attach mechanism | |
459 bool AttachListener::is_init_trigger() { | |
460 if (init_at_startup() || is_initialized()) { | |
461 return false; // initialized at startup or already initialized | |
462 } | |
463 char fn[32]; | |
464 sprintf(fn, ".attach_pid%d", os::current_process_id()); | |
465 int ret; | |
466 struct stat64 st; | |
467 RESTARTABLE(::stat64(fn, &st), ret); | |
468 if (ret == -1) { | |
469 sprintf(fn, "/tmp/.attach_pid%d", os::current_process_id()); | |
470 RESTARTABLE(::stat64(fn, &st), ret); | |
471 } | |
472 if (ret == 0) { | |
473 // simple check to avoid starting the attach mechanism when | |
474 // a bogus user creates the file | |
475 if (st.st_uid == geteuid()) { | |
476 init(); | |
477 return true; | |
478 } | |
479 } | |
480 return false; | |
481 } | |
482 | |
483 // if VM aborts then remove listener | |
484 void AttachListener::abort() { | |
485 listener_cleanup(); | |
486 } | |
487 | |
488 void AttachListener::pd_data_dump() { | |
489 os::signal_notify(SIGQUIT); | |
490 } | |
491 | |
492 AttachOperationFunctionInfo* AttachListener::pd_find_operation(const char* n) { | |
493 return NULL; | |
494 } | |
495 | |
496 jint AttachListener::pd_set_flag(AttachOperation* op, outputStream* out) { | |
497 out->print_cr("flag '%s' cannot be changed", op->arg(0)); | |
498 return JNI_ERR; | |
499 } | |
500 | |
501 void AttachListener::pd_detachall() { | |
502 // do nothing for now | |
503 } |