Thu, 04 Apr 2013 10:01:26 -0700
8003310: Enable -Wunused-function when compiling with gcc
Summary: Add the -Wunused-function flag and remove a number of unused functions.
Reviewed-by: dholmes, coleenp, kvn
1 /*
2 * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "runtime/interfaceSupport.hpp"
27 #include "runtime/os.hpp"
28 #include "services/attachListener.hpp"
29 #include "services/dtraceAttacher.hpp"
31 #include <door.h>
32 #include <string.h>
33 #include <signal.h>
34 #include <sys/types.h>
35 #include <sys/socket.h>
36 #include <sys/stat.h>
38 // stropts.h uses STR in stream ioctl defines
39 #undef STR
40 #include <stropts.h>
41 #undef STR
42 #define STR(a) #a
44 // The attach mechanism on Solaris is implemented using the Doors IPC
45 // mechanism. The first tool to attempt to attach causes the attach
46 // listener thread to startup. This thread creats a door that is
47 // associated with a function that enqueues an operation to the attach
48 // listener. The door is attached to a file in the file system so that
49 // client (tools) can locate it. To enqueue an operation to the VM the
50 // client calls through the door which invokes the enqueue function in
51 // this process. The credentials of the client are checked and if the
52 // effective uid matches this process then the operation is enqueued.
53 // When an operation completes the attach listener is required to send the
54 // operation result and any result data to the client. In this implementation
55 // the result is returned via a UNIX domain socket. A pair of connected
56 // sockets (socketpair) is created in the enqueue function and the file
57 // descriptor for one of the sockets is returned to the client as the
58 // return from the door call. The other end is retained in this process.
59 // When the operation completes the result is sent to the client and
60 // the socket is closed.
62 // forward reference
63 class SolarisAttachOperation;
65 class SolarisAttachListener: AllStatic {
66 private:
68 // the path to which we attach the door file descriptor
69 static char _door_path[PATH_MAX+1];
70 static volatile bool _has_door_path;
72 // door descriptor returned by door_create
73 static int _door_descriptor;
75 static void set_door_path(char* path) {
76 if (path == NULL) {
77 _has_door_path = false;
78 } else {
79 strncpy(_door_path, path, PATH_MAX);
80 _door_path[PATH_MAX] = '\0'; // ensure it's nul terminated
81 _has_door_path = true;
82 }
83 }
85 static void set_door_descriptor(int dd) { _door_descriptor = dd; }
87 // mutex to protect operation list
88 static mutex_t _mutex;
90 // semaphore to wakeup listener thread
91 static sema_t _wakeup;
93 static mutex_t* mutex() { return &_mutex; }
94 static sema_t* wakeup() { return &_wakeup; }
96 // enqueued operation list
97 static SolarisAttachOperation* _head;
98 static SolarisAttachOperation* _tail;
100 static SolarisAttachOperation* head() { return _head; }
101 static void set_head(SolarisAttachOperation* head) { _head = head; }
103 static SolarisAttachOperation* tail() { return _tail; }
104 static void set_tail(SolarisAttachOperation* tail) { _tail = tail; }
106 // create the door
107 static int create_door();
109 public:
110 enum {
111 ATTACH_PROTOCOL_VER = 1 // protocol version
112 };
113 enum {
114 ATTACH_ERROR_BADREQUEST = 100, // error code returned by
115 ATTACH_ERROR_BADVERSION = 101, // the door call
116 ATTACH_ERROR_RESOURCE = 102,
117 ATTACH_ERROR_INTERNAL = 103,
118 ATTACH_ERROR_DENIED = 104
119 };
121 // initialize the listener
122 static int init();
124 static bool has_door_path() { return _has_door_path; }
125 static char* door_path() { return _door_path; }
126 static int door_descriptor() { return _door_descriptor; }
128 // enqueue an operation
129 static void enqueue(SolarisAttachOperation* op);
131 // dequeue an operation
132 static SolarisAttachOperation* dequeue();
133 };
136 // SolarisAttachOperation is an AttachOperation that additionally encapsulates
137 // a socket connection to the requesting client/tool. SolarisAttachOperation
138 // can additionally be held in a linked list.
140 class SolarisAttachOperation: public AttachOperation {
141 private:
142 friend class SolarisAttachListener;
144 // connection to client
145 int _socket;
147 // linked list support
148 SolarisAttachOperation* _next;
150 SolarisAttachOperation* next() { return _next; }
151 void set_next(SolarisAttachOperation* next) { _next = next; }
153 public:
154 void complete(jint res, bufferedStream* st);
156 int socket() const { return _socket; }
157 void set_socket(int s) { _socket = s; }
159 SolarisAttachOperation(char* name) : AttachOperation(name) {
160 set_socket(-1);
161 set_next(NULL);
162 }
163 };
165 // statics
166 char SolarisAttachListener::_door_path[PATH_MAX+1];
167 volatile bool SolarisAttachListener::_has_door_path;
168 int SolarisAttachListener::_door_descriptor = -1;
169 mutex_t SolarisAttachListener::_mutex;
170 sema_t SolarisAttachListener::_wakeup;
171 SolarisAttachOperation* SolarisAttachListener::_head = NULL;
172 SolarisAttachOperation* SolarisAttachListener::_tail = NULL;
174 // Supporting class to help split a buffer into individual components
175 class ArgumentIterator : public StackObj {
176 private:
177 char* _pos;
178 char* _end;
179 public:
180 ArgumentIterator(char* arg_buffer, size_t arg_size) {
181 _pos = arg_buffer;
182 _end = _pos + arg_size - 1;
183 }
184 char* next() {
185 if (*_pos == '\0') {
186 return NULL;
187 }
188 char* res = _pos;
189 char* next_pos = strchr(_pos, '\0');
190 if (next_pos < _end) {
191 next_pos++;
192 }
193 _pos = next_pos;
194 return res;
195 }
196 };
198 // Calls from the door function to check that the client credentials
199 // match this process. Returns 0 if credentials okay, otherwise -1.
200 static int check_credentials() {
201 door_cred_t cred_info;
203 // get client credentials
204 if (door_cred(&cred_info) == -1) {
205 return -1; // unable to get them
206 }
208 // get our euid/eguid (probably could cache these)
209 uid_t euid = geteuid();
210 gid_t egid = getegid();
212 // check that the effective uid/gid matches - discuss this with Jeff.
213 if (cred_info.dc_euid == euid && cred_info.dc_egid == egid) {
214 return 0; // okay
215 } else {
216 return -1; // denied
217 }
218 }
221 // Parses the argument buffer to create an AttachOperation that we should
222 // enqueue to the attach listener.
223 // The buffer is expected to be formatted as follows:
224 // <ver>0<cmd>0<arg>0<arg>0<arg>0
225 // where <ver> is the version number (must be "1"), <cmd> is the command
226 // name ("load, "datadump", ...) and <arg> is an argument.
227 //
228 static SolarisAttachOperation* create_operation(char* argp, size_t arg_size, int* err) {
229 // assume bad request until parsed
230 *err = SolarisAttachListener::ATTACH_ERROR_BADREQUEST;
232 if (arg_size < 2 || argp[arg_size-1] != '\0') {
233 return NULL; // no ver or not null terminated
234 }
236 // Use supporting class to iterate over the buffer
237 ArgumentIterator args(argp, arg_size);
239 // First check the protocol version
240 char* ver = args.next();
241 if (ver == NULL) {
242 return NULL;
243 }
244 if (atoi(ver) != SolarisAttachListener::ATTACH_PROTOCOL_VER) {
245 *err = SolarisAttachListener::ATTACH_ERROR_BADVERSION;
246 return NULL;
247 }
249 // Get command name and create the operation
250 char* name = args.next();
251 if (name == NULL || strlen(name) > AttachOperation::name_length_max) {
252 return NULL;
253 }
254 SolarisAttachOperation* op = new SolarisAttachOperation(name);
256 // Iterate over the arguments
257 for (int i=0; i<AttachOperation::arg_count_max; i++) {
258 char* arg = args.next();
259 if (arg == NULL) {
260 op->set_arg(i, NULL);
261 } else {
262 if (strlen(arg) > AttachOperation::arg_length_max) {
263 delete op;
264 return NULL;
265 }
266 op->set_arg(i, arg);
267 }
268 }
270 // return operation
271 *err = 0;
272 return op;
273 }
275 // create special operation to indicate all clients have detached
276 static SolarisAttachOperation* create_detachall_operation() {
277 return new SolarisAttachOperation(AttachOperation::detachall_operation_name());
278 }
280 // This is door function which the client executes via a door_call.
281 extern "C" {
282 static void enqueue_proc(void* cookie, char* argp, size_t arg_size,
283 door_desc_t* dt, uint_t n_desc)
284 {
285 int return_fd = -1;
286 SolarisAttachOperation* op = NULL;
288 // no listener
289 jint res = 0;
290 if (!AttachListener::is_initialized()) {
291 // how did we get here?
292 debug_only(warning("door_call when not enabled"));
293 res = (jint)SolarisAttachListener::ATTACH_ERROR_INTERNAL;
294 }
296 // check client credentials
297 if (res == 0) {
298 if (check_credentials() != 0) {
299 res = (jint)SolarisAttachListener::ATTACH_ERROR_DENIED;
300 }
301 }
303 // if we are stopped at ShowMessageBoxOnError then maybe we can
304 // load a diagnostic library
305 if (res == 0 && is_error_reported()) {
306 if (ShowMessageBoxOnError) {
307 // TBD - support loading of diagnostic library here
308 }
310 // can't enqueue operation after fatal error
311 res = (jint)SolarisAttachListener::ATTACH_ERROR_RESOURCE;
312 }
314 // create the operation
315 if (res == 0) {
316 int err;
317 op = create_operation(argp, arg_size, &err);
318 res = (op == NULL) ? (jint)err : 0;
319 }
321 // create a pair of connected sockets. Store the file descriptor
322 // for one end in the operation and enqueue the operation. The
323 // file descriptor for the other end wil be returned to the client.
324 if (res == 0) {
325 int s[2];
326 if (socketpair(PF_UNIX, SOCK_STREAM, 0, s) < 0) {
327 delete op;
328 res = (jint)SolarisAttachListener::ATTACH_ERROR_RESOURCE;
329 } else {
330 op->set_socket(s[0]);
331 return_fd = s[1];
332 SolarisAttachListener::enqueue(op);
333 }
334 }
336 // Return 0 (success) + file descriptor, or non-0 (error)
337 if (res == 0) {
338 door_desc_t desc;
339 // DOOR_RELEASE flag makes sure fd is closed after passing it to
340 // the client. See door_return(3DOOR) man page.
341 desc.d_attributes = DOOR_DESCRIPTOR | DOOR_RELEASE;
342 desc.d_data.d_desc.d_descriptor = return_fd;
343 door_return((char*)&res, sizeof(res), &desc, 1);
344 } else {
345 door_return((char*)&res, sizeof(res), NULL, 0);
346 }
347 }
348 }
350 // atexit hook to detach the door and remove the file
351 extern "C" {
352 static void listener_cleanup() {
353 static int cleanup_done;
354 if (!cleanup_done) {
355 cleanup_done = 1;
356 int dd = SolarisAttachListener::door_descriptor();
357 if (dd >= 0) {
358 ::close(dd);
359 }
360 if (SolarisAttachListener::has_door_path()) {
361 char* path = SolarisAttachListener::door_path();
362 ::fdetach(path);
363 ::unlink(path);
364 }
365 }
366 }
367 }
369 // Create the door
370 int SolarisAttachListener::create_door() {
371 char door_path[PATH_MAX+1];
372 char initial_path[PATH_MAX+1];
373 int fd, res;
375 // register exit function
376 ::atexit(listener_cleanup);
378 // create the door descriptor
379 int dd = ::door_create(enqueue_proc, NULL, 0);
380 if (dd < 0) {
381 return -1;
382 }
384 // create initial file to attach door descriptor
385 snprintf(door_path, sizeof(door_path), "%s/.java_pid%d",
386 os::get_temp_directory(), os::current_process_id());
387 snprintf(initial_path, sizeof(initial_path), "%s.tmp", door_path);
388 RESTARTABLE(::creat(initial_path, S_IRUSR | S_IWUSR), fd);
389 if (fd == -1) {
390 debug_only(warning("attempt to create %s failed", initial_path));
391 ::door_revoke(dd);
392 return -1;
393 }
394 assert(fd >= 0, "bad file descriptor");
395 RESTARTABLE(::close(fd), res);
397 // attach the door descriptor to the file
398 if ((res = ::fattach(dd, initial_path)) == -1) {
399 // if busy then detach and try again
400 if (errno == EBUSY) {
401 ::fdetach(initial_path);
402 res = ::fattach(dd, initial_path);
403 }
404 if (res == -1) {
405 ::door_revoke(dd);
406 dd = -1;
407 }
408 }
410 // rename file so that clients can attach
411 if (dd >= 0) {
412 if (::rename(initial_path, door_path) == -1) {
413 RESTARTABLE(::close(dd), res);
414 ::fdetach(initial_path);
415 dd = -1;
416 }
417 }
418 if (dd >= 0) {
419 set_door_descriptor(dd);
420 set_door_path(door_path);
421 } else {
422 // unable to create door, attach it to file, or rename file into place
423 ::unlink(initial_path);
424 return -1;
425 }
427 return 0;
428 }
430 // Initialization - create the door, locks, and other initialization
431 int SolarisAttachListener::init() {
432 if (create_door()) {
433 return -1;
434 }
436 int status = os::Solaris::mutex_init(&_mutex);
437 assert_status(status==0, status, "mutex_init");
439 status = ::sema_init(&_wakeup, 0, NULL, NULL);
440 assert_status(status==0, status, "sema_init");
442 set_head(NULL);
443 set_tail(NULL);
445 return 0;
446 }
448 // Dequeue an operation
449 SolarisAttachOperation* SolarisAttachListener::dequeue() {
450 for (;;) {
451 int res;
453 // wait for somebody to enqueue something
454 while ((res = ::sema_wait(wakeup())) == EINTR)
455 ;
456 if (res) {
457 warning("sema_wait failed: %s", strerror(res));
458 return NULL;
459 }
461 // lock the list
462 res = os::Solaris::mutex_lock(mutex());
463 assert(res == 0, "mutex_lock failed");
465 // remove the head of the list
466 SolarisAttachOperation* op = head();
467 if (op != NULL) {
468 set_head(op->next());
469 if (head() == NULL) {
470 set_tail(NULL);
471 }
472 }
474 // unlock
475 os::Solaris::mutex_unlock(mutex());
477 // if we got an operation when return it.
478 if (op != NULL) {
479 return op;
480 }
481 }
482 }
484 // Enqueue an operation
485 void SolarisAttachListener::enqueue(SolarisAttachOperation* op) {
486 // lock list
487 int res = os::Solaris::mutex_lock(mutex());
488 assert(res == 0, "mutex_lock failed");
490 // enqueue at tail
491 op->set_next(NULL);
492 if (head() == NULL) {
493 set_head(op);
494 } else {
495 tail()->set_next(op);
496 }
497 set_tail(op);
499 // wakeup the attach listener
500 RESTARTABLE(::sema_post(wakeup()), res);
501 assert(res == 0, "sema_post failed");
503 // unlock
504 os::Solaris::mutex_unlock(mutex());
505 }
508 // support function - writes the (entire) buffer to a socket
509 static int write_fully(int s, char* buf, int len) {
510 do {
511 int n = ::write(s, buf, len);
512 if (n == -1) {
513 if (errno != EINTR) return -1;
514 } else {
515 buf += n;
516 len -= n;
517 }
518 }
519 while (len > 0);
520 return 0;
521 }
523 // Complete an operation by sending the operation result and any result
524 // output to the client. At this time the socket is in blocking mode so
525 // potentially we can block if there is a lot of data and the client is
526 // non-responsive. For most operations this is a non-issue because the
527 // default send buffer is sufficient to buffer everything. In the future
528 // if there are operations that involves a very big reply then it the
529 // socket could be made non-blocking and a timeout could be used.
531 void SolarisAttachOperation::complete(jint res, bufferedStream* st) {
532 if (this->socket() >= 0) {
533 JavaThread* thread = JavaThread::current();
534 ThreadBlockInVM tbivm(thread);
536 thread->set_suspend_equivalent();
537 // cleared by handle_special_suspend_equivalent_condition() or
538 // java_suspend_self() via check_and_wait_while_suspended()
540 // write operation result
541 char msg[32];
542 sprintf(msg, "%d\n", res);
543 int rc = write_fully(this->socket(), msg, strlen(msg));
545 // write any result data
546 if (rc == 0) {
547 write_fully(this->socket(), (char*) st->base(), st->size());
548 ::shutdown(this->socket(), 2);
549 }
551 // close socket and we're done
552 RESTARTABLE(::close(this->socket()), rc);
554 // were we externally suspended while we were waiting?
555 thread->check_and_wait_while_suspended();
556 }
557 delete this;
558 }
561 // AttachListener functions
563 AttachOperation* AttachListener::dequeue() {
564 JavaThread* thread = JavaThread::current();
565 ThreadBlockInVM tbivm(thread);
567 thread->set_suspend_equivalent();
568 // cleared by handle_special_suspend_equivalent_condition() or
569 // java_suspend_self() via check_and_wait_while_suspended()
571 AttachOperation* op = SolarisAttachListener::dequeue();
573 // were we externally suspended while we were waiting?
574 thread->check_and_wait_while_suspended();
576 return op;
577 }
579 int AttachListener::pd_init() {
580 JavaThread* thread = JavaThread::current();
581 ThreadBlockInVM tbivm(thread);
583 thread->set_suspend_equivalent();
584 // cleared by handle_special_suspend_equivalent_condition() or
585 // java_suspend_self()
587 int ret_code = SolarisAttachListener::init();
589 // were we externally suspended while we were waiting?
590 thread->check_and_wait_while_suspended();
592 return ret_code;
593 }
595 // Attach Listener is started lazily except in the case when
596 // +ReduseSignalUsage is used
597 bool AttachListener::init_at_startup() {
598 if (ReduceSignalUsage) {
599 return true;
600 } else {
601 return false;
602 }
603 }
605 // If the file .attach_pid<pid> exists in the working directory
606 // or /tmp then this is the trigger to start the attach mechanism
607 bool AttachListener::is_init_trigger() {
608 if (init_at_startup() || is_initialized()) {
609 return false; // initialized at startup or already initialized
610 }
611 char fn[PATH_MAX+1];
612 sprintf(fn, ".attach_pid%d", os::current_process_id());
613 int ret;
614 struct stat64 st;
615 RESTARTABLE(::stat64(fn, &st), ret);
616 if (ret == -1) {
617 snprintf(fn, sizeof(fn), "%s/.attach_pid%d",
618 os::get_temp_directory(), os::current_process_id());
619 RESTARTABLE(::stat64(fn, &st), ret);
620 }
621 if (ret == 0) {
622 // simple check to avoid starting the attach mechanism when
623 // a bogus user creates the file
624 if (st.st_uid == geteuid()) {
625 init();
626 return true;
627 }
628 }
629 return false;
630 }
632 // if VM aborts then detach/cleanup
633 void AttachListener::abort() {
634 listener_cleanup();
635 }
637 void AttachListener::pd_data_dump() {
638 os::signal_notify(SIGQUIT);
639 }
641 static jint enable_dprobes(AttachOperation* op, outputStream* out) {
642 const char* probe = op->arg(0);
643 if (probe == NULL || probe[0] == '\0') {
644 out->print_cr("No probe specified");
645 return JNI_ERR;
646 } else {
647 int probe_typess = atoi(probe);
648 if (errno) {
649 out->print_cr("invalid probe type");
650 return JNI_ERR;
651 } else {
652 DTrace::enable_dprobes(probe_typess);
653 return JNI_OK;
654 }
655 }
656 }
658 // platform specific operations table
659 static AttachOperationFunctionInfo funcs[] = {
660 { "enabledprobes", enable_dprobes },
661 { NULL, NULL }
662 };
664 AttachOperationFunctionInfo* AttachListener::pd_find_operation(const char* name) {
665 int i;
666 for (i = 0; funcs[i].name != NULL; i++) {
667 if (strcmp(funcs[i].name, name) == 0) {
668 return &funcs[i];
669 }
670 }
671 return NULL;
672 }
674 // Solaris specific global flag set. Currently, we support only
675 // changing ExtendedDTraceProbes flag.
676 jint AttachListener::pd_set_flag(AttachOperation* op, outputStream* out) {
677 const char* name = op->arg(0);
678 assert(name != NULL, "flag name should not be null");
679 bool flag = true;
680 const char* arg1;
681 if ((arg1 = op->arg(1)) != NULL) {
682 flag = (atoi(arg1) != 0);
683 if (errno) {
684 out->print_cr("flag value has to be an integer");
685 return JNI_ERR;
686 }
687 }
689 if (strcmp(name, "ExtendedDTraceProbes") == 0) {
690 DTrace::set_extended_dprobes(flag);
691 return JNI_OK;
692 }
694 if (strcmp(name, "DTraceMonitorProbes") == 0) {
695 DTrace::set_monitor_dprobes(flag);
696 return JNI_OK;
697 }
699 out->print_cr("flag '%s' cannot be changed", name);
700 return JNI_ERR;
701 }
703 void AttachListener::pd_detachall() {
704 DTrace::detach_all_clients();
705 }