Mercurial > hg > truffle
annotate src/os/linux/vm/attachListener_linux.cpp @ 196:d1605aabd0a1 jdk7-b30
6719955: Update copyright year
Summary: Update copyright year for files that have been modified in 2008
Reviewed-by: ohair, tbell
| author | xdono |
|---|---|
| date | Wed, 02 Jul 2008 12:55:16 -0700 |
| parents | 485d403e94e1 |
| 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 } |