1 | /* Copyright (C) 1991-2024 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <assert.h> |
19 | #include <stdio.h> |
20 | #include <stdlib.h> |
21 | #include <string.h> |
22 | |
23 | #include <lock-intern.h> /* For `struct mutex'. */ |
24 | #include <pthreadP.h> |
25 | #include <mach.h> |
26 | #include <mach/setup-thread.h> |
27 | #include <mach/thread_switch.h> |
28 | #include <mach/mig_support.h> |
29 | #include <mach/vm_param.h> |
30 | |
31 | #include <hurd.h> |
32 | #include <hurd/id.h> |
33 | #include <hurd/signal.h> |
34 | |
35 | #include "hurdfault.h" |
36 | #include "hurdmalloc.h" /* XXX */ |
37 | #include "../locale/localeinfo.h" |
38 | |
39 | #include <libc-diag.h> |
40 | |
41 | const char *_hurdsig_getenv (const char *); |
42 | |
43 | struct mutex _hurd_siglock; |
44 | int _hurd_stopped; |
45 | |
46 | /* Port that receives signals and other miscellaneous messages. */ |
47 | mach_port_t _hurd_msgport; |
48 | |
49 | /* Thread listening on it. */ |
50 | thread_t _hurd_msgport_thread; |
51 | |
52 | /* These are set up by _hurdsig_init. */ |
53 | unsigned long int __hurd_sigthread_stack_base; |
54 | unsigned long int __hurd_sigthread_stack_end; |
55 | |
56 | /* Linked-list of per-thread signal state. */ |
57 | struct hurd_sigstate *_hurd_sigstates; |
58 | |
59 | /* Sigstate for the task-global signals. */ |
60 | struct hurd_sigstate *_hurd_global_sigstate; |
61 | |
62 | /* Timeout for RPC's after interrupt_operation. */ |
63 | mach_msg_timeout_t _hurd_interrupted_rpc_timeout = 60000; |
64 | |
65 | static void |
66 | default_sigaction (struct sigaction actions[NSIG]) |
67 | { |
68 | int signo; |
69 | |
70 | __sigemptyset (set: &actions[0].sa_mask); |
71 | actions[0].sa_flags = SA_RESTART; |
72 | actions[0].sa_handler = SIG_DFL; |
73 | |
74 | for (signo = 1; signo < NSIG; ++signo) |
75 | actions[signo] = actions[0]; |
76 | } |
77 | |
78 | struct hurd_sigstate * |
79 | _hurd_thread_sigstate (thread_t thread) |
80 | { |
81 | struct hurd_sigstate *ss; |
82 | __mutex_lock (&_hurd_siglock); |
83 | for (ss = _hurd_sigstates; ss != NULL; ss = ss->next) |
84 | if (ss->thread == thread) |
85 | break; |
86 | if (ss == NULL) |
87 | { |
88 | ss = malloc (sizeof (*ss)); |
89 | if (ss == NULL) |
90 | __libc_fatal (message: "hurd: Can't allocate sigstate\n" ); |
91 | __spin_lock_init (&ss->critical_section_lock); |
92 | __spin_lock_init (&ss->lock); |
93 | ss->thread = thread; |
94 | |
95 | /* Initialize default state. */ |
96 | __sigemptyset (set: &ss->blocked); |
97 | __sigemptyset (set: &ss->pending); |
98 | memset (s: &ss->sigaltstack, c: 0, n: sizeof (ss->sigaltstack)); |
99 | ss->sigaltstack.ss_flags |= SS_DISABLE; |
100 | ss->preemptors = NULL; |
101 | ss->suspended = MACH_PORT_NULL; |
102 | ss->intr_port = MACH_PORT_NULL; |
103 | ss->context = NULL; |
104 | ss->active_resources = NULL; |
105 | ss->cancel = 0; |
106 | ss->cancel_hook = NULL; |
107 | |
108 | if (thread == MACH_PORT_NULL) |
109 | { |
110 | /* Process-wide sigstate, use the system defaults. */ |
111 | default_sigaction (actions: ss->actions); |
112 | |
113 | /* The global sigstate is not added to the _hurd_sigstates list. |
114 | It is created with _hurd_thread_sigstate (MACH_PORT_NULL) |
115 | but should be accessed through _hurd_global_sigstate. */ |
116 | } |
117 | else |
118 | { |
119 | error_t err; |
120 | |
121 | /* Use the global actions as a default for new threads. */ |
122 | struct hurd_sigstate *s = _hurd_global_sigstate; |
123 | if (s) |
124 | { |
125 | __spin_lock (&s->lock); |
126 | memcpy (dest: ss->actions, src: s->actions, n: sizeof (s->actions)); |
127 | __spin_unlock (&s->lock); |
128 | } |
129 | else |
130 | default_sigaction (actions: ss->actions); |
131 | |
132 | ss->next = _hurd_sigstates; |
133 | _hurd_sigstates = ss; |
134 | |
135 | err = __mach_port_mod_refs (__mach_task_self (), thread, |
136 | MACH_PORT_RIGHT_SEND, 1); |
137 | if (err) |
138 | __libc_fatal (message: "hurd: Can't add reference on Mach thread\n" ); |
139 | } |
140 | } |
141 | __mutex_unlock (&_hurd_siglock); |
142 | return ss; |
143 | } |
144 | libc_hidden_def (_hurd_thread_sigstate) |
145 | |
146 | /* Destroy a sigstate structure. Called by libpthread just before the |
147 | * corresponding thread is terminated. */ |
148 | void |
149 | _hurd_sigstate_delete (thread_t thread) |
150 | { |
151 | struct hurd_sigstate **ssp, *ss; |
152 | |
153 | __mutex_lock (&_hurd_siglock); |
154 | for (ssp = &_hurd_sigstates; *ssp; ssp = &(*ssp)->next) |
155 | if ((*ssp)->thread == thread) |
156 | break; |
157 | |
158 | ss = *ssp; |
159 | if (ss) |
160 | *ssp = ss->next; |
161 | |
162 | __mutex_unlock (&_hurd_siglock); |
163 | if (ss) |
164 | { |
165 | if (ss->thread != MACH_PORT_NULL) |
166 | __mach_port_deallocate (__mach_task_self (), ss->thread); |
167 | |
168 | free (ss); |
169 | } |
170 | } |
171 | |
172 | /* Make SS a global receiver, with pthread signal semantics. */ |
173 | void |
174 | _hurd_sigstate_set_global_rcv (struct hurd_sigstate *ss) |
175 | { |
176 | assert (ss->thread != MACH_PORT_NULL); |
177 | ss->actions[0].sa_handler = SIG_IGN; |
178 | } |
179 | libc_hidden_def (_hurd_sigstate_set_global_rcv) |
180 | |
181 | /* Check whether SS is a global receiver. */ |
182 | static int |
183 | sigstate_is_global_rcv (const struct hurd_sigstate *ss) |
184 | { |
185 | return (_hurd_global_sigstate != NULL) |
186 | && (ss->actions[0].sa_handler == SIG_IGN); |
187 | } |
188 | libc_hidden_def (_hurd_sigstate_delete) |
189 | |
190 | /* Lock/unlock a hurd_sigstate structure. If the accessors below require |
191 | it, the global sigstate will be locked as well. */ |
192 | void |
193 | _hurd_sigstate_lock (struct hurd_sigstate *ss) |
194 | { |
195 | if (sigstate_is_global_rcv (ss)) |
196 | __spin_lock (&_hurd_global_sigstate->lock); |
197 | __spin_lock (&ss->lock); |
198 | } |
199 | libc_hidden_def (_hurd_sigstate_lock) |
200 | |
201 | void |
202 | _hurd_sigstate_unlock (struct hurd_sigstate *ss) |
203 | { |
204 | __spin_unlock (&ss->lock); |
205 | if (sigstate_is_global_rcv (ss)) |
206 | __spin_unlock (&_hurd_global_sigstate->lock); |
207 | } |
208 | libc_hidden_def (_hurd_sigstate_unlock) |
209 | |
210 | /* Retrieve a thread's full set of pending signals, including the global |
211 | ones if appropriate. SS must be locked. */ |
212 | sigset_t |
213 | _hurd_sigstate_pending (const struct hurd_sigstate *ss) |
214 | { |
215 | sigset_t pending = ss->pending; |
216 | if (sigstate_is_global_rcv (ss)) |
217 | __sigorset (dest: &pending, left: &pending, right: &_hurd_global_sigstate->pending); |
218 | return pending; |
219 | } |
220 | libc_hidden_def (_hurd_sigstate_pending) |
221 | |
222 | /* Clear a pending signal and return the associated detailed |
223 | signal information. SS must be locked, and must have signal SIGNO |
224 | pending, either directly or through the global sigstate. */ |
225 | static struct hurd_signal_detail |
226 | sigstate_clear_pending (struct hurd_sigstate *ss, int signo) |
227 | { |
228 | if (sigstate_is_global_rcv (ss) |
229 | && __sigismember (set: &_hurd_global_sigstate->pending, sig: signo)) |
230 | { |
231 | __sigdelset (set: &_hurd_global_sigstate->pending, sig: signo); |
232 | return _hurd_global_sigstate->pending_data[signo]; |
233 | } |
234 | |
235 | assert (__sigismember (&ss->pending, signo)); |
236 | __sigdelset (set: &ss->pending, sig: signo); |
237 | return ss->pending_data[signo]; |
238 | } |
239 | |
240 | /* Retrieve a thread's action vector. SS must be locked. */ |
241 | struct sigaction * |
242 | _hurd_sigstate_actions (struct hurd_sigstate *ss) |
243 | { |
244 | if (sigstate_is_global_rcv (ss)) |
245 | return _hurd_global_sigstate->actions; |
246 | else |
247 | return ss->actions; |
248 | } |
249 | |
250 | |
251 | /* Signal delivery itself is on this page. */ |
252 | |
253 | #include <hurd/fd.h> |
254 | #include <hurd/crash.h> |
255 | #include <hurd/resource.h> |
256 | #include <hurd/paths.h> |
257 | #include <setjmp.h> |
258 | #include <fcntl.h> |
259 | #include <sys/wait.h> |
260 | #include <thread_state.h> |
261 | #include <hurd/msg_server.h> |
262 | #include <hurd/msg_reply.h> /* For __msg_sig_post_reply. */ |
263 | #include <hurd/interrupt.h> |
264 | #include <unistd.h> |
265 | |
266 | |
267 | /* Call the crash dump server to mummify us before we die. |
268 | Returns nonzero if a core file was written. */ |
269 | static int |
270 | write_corefile (int signo, const struct hurd_signal_detail *detail) |
271 | { |
272 | error_t err; |
273 | mach_port_t coreserver; |
274 | file_t file, coredir; |
275 | const char *name; |
276 | |
277 | /* Don't bother locking since we just read the one word. */ |
278 | rlim_t corelimit = _hurd_rlimits[RLIMIT_CORE].rlim_cur; |
279 | |
280 | if (corelimit == 0) |
281 | /* No core dumping, thank you very much. Note that this makes |
282 | `ulimit -c 0' prevent crash-suspension too, which is probably |
283 | what the user wanted. */ |
284 | return 0; |
285 | |
286 | /* XXX RLIMIT_CORE: |
287 | When we have a protocol to make the server return an error |
288 | for RLIMIT_FSIZE, then tell the corefile fs server the RLIMIT_CORE |
289 | value in place of the RLIMIT_FSIZE value. */ |
290 | |
291 | /* First get a port to the core dumping server. */ |
292 | coreserver = MACH_PORT_NULL; |
293 | name = _hurdsig_getenv ("CRASHSERVER" ); |
294 | if (name != NULL) |
295 | coreserver = __file_name_lookup (name, 0, 0); |
296 | if (coreserver == MACH_PORT_NULL) |
297 | coreserver = __file_name_lookup (_SERVERS_CRASH, 0, 0); |
298 | if (coreserver == MACH_PORT_NULL) |
299 | return 0; |
300 | |
301 | /* Get a port to the directory where the new core file will reside. */ |
302 | file = MACH_PORT_NULL; |
303 | name = _hurdsig_getenv ("COREFILE" ); |
304 | if (name == NULL) |
305 | name = "core" ; |
306 | coredir = __file_name_split (name, (char **) &name); |
307 | if (coredir != MACH_PORT_NULL) |
308 | /* Create the new file, but don't link it into the directory yet. */ |
309 | __dir_mkfile (coredir, O_WRONLY|O_CREAT, |
310 | 0600 & ~_hurd_umask, /* XXX ? */ |
311 | &file); |
312 | |
313 | /* Call the core dumping server to write the core file. */ |
314 | err = __crash_dump_task (coreserver, |
315 | __mach_task_self (), |
316 | file, |
317 | signo, detail->code, detail->error, |
318 | detail->exc, detail->exc_code, detail->exc_subcode, |
319 | _hurd_ports[INIT_PORT_CTTYID].port, |
320 | MACH_MSG_TYPE_COPY_SEND); |
321 | __mach_port_deallocate (__mach_task_self (), coreserver); |
322 | |
323 | if (! err && file != MACH_PORT_NULL) |
324 | /* The core dump into FILE succeeded, so now link it into the |
325 | directory. */ |
326 | err = __dir_link (coredir, file, name, 1); |
327 | __mach_port_deallocate (__mach_task_self (), file); |
328 | __mach_port_deallocate (__mach_task_self (), coredir); |
329 | return !err && file != MACH_PORT_NULL; |
330 | } |
331 | |
332 | |
333 | /* The lowest-numbered thread state flavor value is 1, |
334 | so we use bit 0 in machine_thread_all_state.set to |
335 | record whether we have done thread_abort. */ |
336 | #define THREAD_ABORTED 1 |
337 | |
338 | /* SS->thread is suspended. Abort the thread and get its basic state. */ |
339 | static void |
340 | abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state, |
341 | void (*reply) (void)) |
342 | { |
343 | assert (ss->thread != MACH_PORT_NULL); |
344 | |
345 | if (!(state->set & THREAD_ABORTED)) |
346 | { |
347 | error_t err = __thread_abort (ss->thread); |
348 | assert_perror (err); |
349 | /* Clear all thread state flavor set bits, because thread_abort may |
350 | have changed the state. */ |
351 | state->set = THREAD_ABORTED; |
352 | } |
353 | |
354 | if (reply) |
355 | (*reply) (); |
356 | |
357 | machine_get_basic_state (ss->thread, state); |
358 | } |
359 | |
360 | /* Find the location of the MiG reply port cell in use by the thread whose |
361 | state is described by THREAD_STATE. If SIGTHREAD is nonzero, make sure |
362 | that this location can be set without faulting, or else return NULL. */ |
363 | |
364 | static mach_port_t * |
365 | interrupted_reply_port_location (thread_t thread, |
366 | struct machine_thread_all_state *thread_state, |
367 | int sigthread) |
368 | { |
369 | mach_port_t *portloc = &THREAD_TCB(thread, thread_state)->reply_port; |
370 | |
371 | if (sigthread && _hurdsig_catch_memory_fault (portloc)) |
372 | /* Faulted trying to read the TCB. */ |
373 | return NULL; |
374 | |
375 | DIAG_PUSH_NEEDS_COMMENT; |
376 | /* GCC 6 and before seem to be confused by the setjmp call inside |
377 | _hurdsig_catch_memory_fault and think that we may be returning a second |
378 | time to here with portloc uninitialized (but we never do). */ |
379 | DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized" ); |
380 | /* Fault now if this pointer is bogus. */ |
381 | *(volatile mach_port_t *) portloc = *portloc; |
382 | DIAG_POP_NEEDS_COMMENT; |
383 | |
384 | if (sigthread) |
385 | _hurdsig_end_catch_fault (); |
386 | |
387 | return portloc; |
388 | } |
389 | |
390 | #include <hurd/sigpreempt.h> |
391 | #include <intr-msg.h> |
392 | |
393 | /* Timeout on interrupt_operation calls. */ |
394 | mach_msg_timeout_t _hurdsig_interrupt_timeout = 1000; |
395 | |
396 | /* SS->thread is suspended. |
397 | |
398 | Abort any interruptible RPC operation the thread is doing. |
399 | |
400 | This uses only the constant member SS->thread and the unlocked, atomically |
401 | set member SS->intr_port, so no locking is needed. |
402 | |
403 | If successfully sent an interrupt_operation and therefore the thread should |
404 | wait for its pending RPC to return (possibly EINTR) before taking the |
405 | incoming signal, returns the reply port to be received on. Otherwise |
406 | returns MACH_PORT_NULL. |
407 | |
408 | SIGNO is used to find the applicable SA_RESTART bit. If SIGNO is zero, |
409 | the RPC fails with EINTR instead of restarting (thread_cancel). |
410 | |
411 | *STATE_CHANGE is set nonzero if STATE->basic was modified and should |
412 | be applied back to the thread if it might ever run again, else zero. */ |
413 | |
414 | mach_port_t |
415 | _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread, |
416 | struct machine_thread_all_state *state, int *state_change, |
417 | void (*reply) (void)) |
418 | { |
419 | extern const void _hurd_intr_rpc_msg_about_to attribute_hidden; |
420 | extern const void _hurd_intr_rpc_msg_setup_done attribute_hidden; |
421 | extern const void _hurd_intr_rpc_msg_in_trap attribute_hidden; |
422 | mach_port_t rcv_port = MACH_PORT_NULL; |
423 | mach_port_t intr_port; |
424 | |
425 | *state_change = 0; |
426 | |
427 | intr_port = ss->intr_port; |
428 | if (intr_port == MACH_PORT_NULL) |
429 | /* No interruption needs done. */ |
430 | return MACH_PORT_NULL; |
431 | |
432 | /* Abort the thread's kernel context, so any pending message send or |
433 | receive completes immediately or aborts. */ |
434 | abort_thread (ss, state, reply); |
435 | |
436 | if (state->basic.PC >= (uintptr_t) &_hurd_intr_rpc_msg_about_to |
437 | && state->basic.PC < (uintptr_t) &_hurd_intr_rpc_msg_in_trap) |
438 | { |
439 | /* The thread is about to do the RPC, but hasn't yet entered |
440 | mach_msg. Importantly, it may have already checked ss->cancel for |
441 | the last time before doing the RPC, so setting that is not enough |
442 | to make it not enter mach_msg. Instead, mutate the thread's state |
443 | so it knows not to try the RPC. |
444 | |
445 | If the thread is past _hurd_intr_rpc_msg_setup_done, just make it |
446 | jump to after the trap, since we know it's safe to do so. Otherwise, |
447 | we know that the thread is yet to check for the MACH_SEND_INTERRUPTED |
448 | value we set below, and will skip the trap by itself. */ |
449 | if (state->basic.PC >= (uintptr_t) &_hurd_intr_rpc_msg_setup_done) |
450 | MACHINE_THREAD_STATE_SET_PC (&state->basic, |
451 | &_hurd_intr_rpc_msg_in_trap); |
452 | state->basic.SYSRETURN = MACH_SEND_INTERRUPTED; |
453 | *state_change = 1; |
454 | } |
455 | else if (state->basic.PC == (uintptr_t) &_hurd_intr_rpc_msg_in_trap |
456 | /* The thread was blocked in the system call. After thread_abort, |
457 | the return value register indicates what state the RPC was in |
458 | when interrupted. */ |
459 | && state->basic.SYSRETURN == MACH_RCV_INTERRUPTED) |
460 | { |
461 | /* The RPC request message was sent and the thread was waiting for the |
462 | reply message; now the message receive has been aborted, so the |
463 | mach_msg call will return MACH_RCV_INTERRUPTED. We must tell the |
464 | server to interrupt the pending operation. The thread must wait for |
465 | the reply message before running the signal handler (to guarantee that |
466 | the operation has finished being interrupted), so our nonzero return |
467 | tells the trampoline code to finish the message receive operation |
468 | before running the handler. */ |
469 | |
470 | mach_port_t *reply = interrupted_reply_port_location (ss->thread, |
471 | state, |
472 | sigthread); |
473 | error_t err = __interrupt_operation (intr_port, |
474 | _hurdsig_interrupt_timeout); |
475 | |
476 | if (err) |
477 | { |
478 | if (reply) |
479 | { |
480 | /* The interrupt didn't work. |
481 | Destroy the receive right the thread is blocked on, and |
482 | replace it with a dead name to keep the name from reuse until |
483 | the therad is done with it. To do this atomically, first |
484 | insert a send right, and then destroy the receive right, |
485 | turning the send right into a dead name. */ |
486 | err = __mach_port_insert_right (__mach_task_self (), |
487 | *reply, *reply, |
488 | MACH_MSG_TYPE_MAKE_SEND); |
489 | assert_perror (err); |
490 | err = __mach_port_mod_refs (__mach_task_self (), *reply, |
491 | MACH_PORT_RIGHT_RECEIVE, -1); |
492 | assert_perror (err); |
493 | } |
494 | |
495 | /* The system call return value register now contains |
496 | MACH_RCV_INTERRUPTED; when mach_msg resumes, it will retry the |
497 | call. Since we have just destroyed the receive right, the retry |
498 | will fail with MACH_RCV_INVALID_NAME. Instead, just change the |
499 | return value here to EINTR so mach_msg will not retry and the |
500 | EINTR error code will propagate up. */ |
501 | state->basic.SYSRETURN = EINTR; |
502 | *state_change = 1; |
503 | } |
504 | else if (reply) |
505 | rcv_port = *reply; |
506 | |
507 | /* All threads whose RPCs were interrupted by the interrupt_operation |
508 | call above will retry their RPCs unless we clear SS->intr_port. So we |
509 | clear it for the thread taking a signal when SA_RESTART is clear, so |
510 | that its call returns EINTR. */ |
511 | if (! signo || !(_hurd_sigstate_actions (ss) [signo].sa_flags & SA_RESTART)) |
512 | ss->intr_port = MACH_PORT_NULL; |
513 | } |
514 | |
515 | return rcv_port; |
516 | } |
517 | |
518 | |
519 | /* Abort the RPCs being run by all threads but this one; |
520 | all other threads should be suspended. If LIVE is nonzero, those |
521 | threads may run again, so they should be adjusted as necessary to be |
522 | happy when resumed. STATE is clobbered as a scratch area; its initial |
523 | contents are ignored, and its contents on return are not useful. */ |
524 | |
525 | static void |
526 | abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live) |
527 | { |
528 | /* We can just loop over the sigstates. Any thread doing something |
529 | interruptible must have one. We needn't bother locking because all |
530 | other threads are stopped. */ |
531 | |
532 | struct hurd_sigstate *ss; |
533 | size_t nthreads; |
534 | mach_port_t *reply_ports; |
535 | |
536 | /* First loop over the sigstates to count them. |
537 | We need to know how big a vector we will need for REPLY_PORTS. */ |
538 | nthreads = 0; |
539 | for (ss = _hurd_sigstates; ss != NULL; ss = ss->next) |
540 | ++nthreads; |
541 | |
542 | reply_ports = alloca (nthreads * sizeof *reply_ports); |
543 | |
544 | nthreads = 0; |
545 | for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads) |
546 | if (ss->thread == _hurd_msgport_thread) |
547 | reply_ports[nthreads] = MACH_PORT_NULL; |
548 | else |
549 | { |
550 | int state_changed; |
551 | state->set = 0; /* Reset scratch area. */ |
552 | |
553 | /* Abort any operation in progress with interrupt_operation. |
554 | Record the reply port the thread is waiting on. |
555 | We will wait for all the replies below. */ |
556 | reply_ports[nthreads] = _hurdsig_abort_rpcs (ss, signo, 1, |
557 | state, &state_changed, |
558 | NULL); |
559 | if (live) |
560 | { |
561 | if (reply_ports[nthreads] != MACH_PORT_NULL) |
562 | { |
563 | /* We will wait for the reply to this RPC below, so the |
564 | thread must issue a new RPC rather than waiting for the |
565 | reply to the one it sent. */ |
566 | state->basic.SYSRETURN = EINTR; |
567 | state_changed = 1; |
568 | } |
569 | if (state_changed) |
570 | /* Aborting the RPC needed to change this thread's state, |
571 | and it might ever run again. So write back its state. */ |
572 | __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR, |
573 | (natural_t *) &state->basic, |
574 | MACHINE_THREAD_STATE_COUNT); |
575 | } |
576 | } |
577 | |
578 | /* Wait for replies from all the successfully interrupted RPCs. */ |
579 | while (nthreads-- > 0) |
580 | if (reply_ports[nthreads] != MACH_PORT_NULL) |
581 | { |
582 | error_t err; |
583 | mach_msg_header_t head; |
584 | err = __mach_msg (&head, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof head, |
585 | reply_ports[nthreads], |
586 | _hurd_interrupted_rpc_timeout, MACH_PORT_NULL); |
587 | switch (err) |
588 | { |
589 | case MACH_RCV_TIMED_OUT: |
590 | case MACH_RCV_TOO_LARGE: |
591 | break; |
592 | |
593 | default: |
594 | assert_perror (err); |
595 | } |
596 | } |
597 | } |
598 | |
599 | /* Wake up any sigsuspend or pselect call that is blocking SS->thread. SS must |
600 | be locked. */ |
601 | static void |
602 | wake_sigsuspend (struct hurd_sigstate *ss) |
603 | { |
604 | error_t err; |
605 | mach_msg_header_t msg; |
606 | |
607 | if (ss->suspended == MACH_PORT_NULL) |
608 | return; |
609 | |
610 | /* There is a sigsuspend waiting. Tell it to wake up. */ |
611 | msg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_MAKE_SEND, 0); |
612 | msg.msgh_remote_port = ss->suspended; |
613 | msg.msgh_local_port = MACH_PORT_NULL; |
614 | /* These values do not matter. */ |
615 | msg.msgh_id = 8675309; /* Jenny, Jenny. */ |
616 | ss->suspended = MACH_PORT_NULL; |
617 | err = __mach_msg (&msg, MACH_SEND_MSG, sizeof msg, 0, |
618 | MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, |
619 | MACH_PORT_NULL); |
620 | assert_perror (err); |
621 | } |
622 | |
623 | struct hurd_signal_preemptor *_hurdsig_preemptors = 0; |
624 | sigset_t _hurdsig_preempted_set; |
625 | |
626 | /* XXX temporary to deal with spelling fix */ |
627 | weak_alias (_hurdsig_preemptors, _hurdsig_preempters) |
628 | |
629 | /* Mask of stop signals. */ |
630 | #define STOPSIGS (__sigmask (SIGTTIN) | __sigmask (SIGTTOU) \ |
631 | | __sigmask (SIGSTOP) | __sigmask (SIGTSTP)) |
632 | |
633 | /* Actual delivery of a single signal. Called with SS unlocked. When |
634 | the signal is delivered, return SS, locked (or, if SS was originally |
635 | _hurd_global_sigstate, the sigstate of the actual thread the signal |
636 | was delivered to). If the signal is being traced, return NULL with |
637 | SS unlocked. */ |
638 | static struct hurd_sigstate * |
639 | post_signal (struct hurd_sigstate *ss, |
640 | int signo, struct hurd_signal_detail *detail, |
641 | int untraced, void (*reply) (void)) |
642 | { |
643 | struct machine_thread_all_state thread_state; |
644 | enum { stop, ignore, core, term, handle } act; |
645 | int ss_suspended; |
646 | |
647 | /* sigaction for preemptors */ |
648 | struct sigaction preempt_sigaction = { |
649 | .sa_flags = SA_RESTART |
650 | }; |
651 | |
652 | struct sigaction *action; |
653 | |
654 | /* Mark the signal as pending. */ |
655 | void mark_pending (void) |
656 | { |
657 | __sigaddset (&ss->pending, signo); |
658 | /* Save the details to be given to the handler when SIGNO is |
659 | unblocked. */ |
660 | ss->pending_data[signo] = *detail; |
661 | } |
662 | |
663 | /* Suspend the process with SIGNO. */ |
664 | void suspend (void) |
665 | { |
666 | /* Stop all other threads and mark ourselves stopped. */ |
667 | __USEPORT (PROC, |
668 | ({ |
669 | /* Hold the siglock while stopping other threads to be |
670 | sure it is not held by another thread afterwards. */ |
671 | __mutex_lock (&_hurd_siglock); |
672 | __proc_dostop (port, _hurd_msgport_thread); |
673 | __mutex_unlock (&_hurd_siglock); |
674 | abort_all_rpcs (signo, &thread_state, 1); |
675 | reply (); |
676 | __proc_mark_stop (port, signo, detail->code); |
677 | })); |
678 | _hurd_stopped = 1; |
679 | } |
680 | /* Resume the process after a suspension. */ |
681 | void resume (void) |
682 | { |
683 | /* Resume the process from being stopped. */ |
684 | thread_t *threads; |
685 | mach_msg_type_number_t nthreads, i; |
686 | error_t err; |
687 | |
688 | if (! _hurd_stopped) |
689 | return; |
690 | |
691 | /* Tell the proc server we are continuing. */ |
692 | __USEPORT (PROC, __proc_mark_cont (port)); |
693 | /* Fetch ports to all our threads and resume them. */ |
694 | err = __task_threads (__mach_task_self (), &threads, &nthreads); |
695 | assert_perror (err); |
696 | for (i = 0; i < nthreads; ++i) |
697 | { |
698 | if (act == handle && threads[i] == ss->thread) |
699 | { |
700 | /* The thread that will run the handler is kept suspended. */ |
701 | ss_suspended = 1; |
702 | } |
703 | else if (threads[i] != _hurd_msgport_thread) |
704 | { |
705 | err = __thread_resume (threads[i]); |
706 | assert_perror (err); |
707 | } |
708 | err = __mach_port_deallocate (__mach_task_self (), |
709 | threads[i]); |
710 | assert_perror (err); |
711 | } |
712 | __vm_deallocate (__mach_task_self (), |
713 | (vm_address_t) threads, |
714 | nthreads * sizeof *threads); |
715 | _hurd_stopped = 0; |
716 | } |
717 | |
718 | error_t err; |
719 | sighandler_t handler; |
720 | |
721 | if (signo == 0) |
722 | { |
723 | if (untraced) |
724 | { |
725 | /* This is PTRACE_CONTINUE. */ |
726 | act = ignore; |
727 | resume (); |
728 | } |
729 | |
730 | /* This call is just to check for pending signals. */ |
731 | _hurd_sigstate_lock (ss); |
732 | return ss; |
733 | } |
734 | |
735 | thread_state.set = 0; /* We know nothing. */ |
736 | |
737 | _hurd_sigstate_lock (ss); |
738 | |
739 | /* If this is a global signal, try to find a thread ready to accept |
740 | it right away. This is especially important for untraced signals, |
741 | since going through the global pending mask would de-untrace them. */ |
742 | if (ss->thread == MACH_PORT_NULL) |
743 | { |
744 | struct hurd_sigstate *; |
745 | |
746 | __mutex_lock (&_hurd_siglock); |
747 | for (rss = _hurd_sigstates; rss != NULL; rss = rss->next) |
748 | { |
749 | if (! sigstate_is_global_rcv (ss: rss)) |
750 | continue; |
751 | |
752 | /* The global sigstate is already locked. */ |
753 | __spin_lock (&rss->lock); |
754 | if (! __sigismember (set: &rss->blocked, sig: signo)) |
755 | { |
756 | ss = rss; |
757 | break; |
758 | } |
759 | __spin_unlock (&rss->lock); |
760 | } |
761 | __mutex_unlock (&_hurd_siglock); |
762 | } |
763 | |
764 | /* We want the preemptors to be able to update the blocking mask |
765 | without affecting the delivery of this signal, so we save the |
766 | current value to test against later. */ |
767 | sigset_t blocked = ss->blocked; |
768 | |
769 | /* Check for a preempted signal. Preempted signals can arrive during |
770 | critical sections. */ |
771 | { |
772 | inline sighandler_t try_preemptor (struct hurd_signal_preemptor *pe) |
773 | { /* PE cannot be null. */ |
774 | do |
775 | { |
776 | if (HURD_PREEMPT_SIGNAL_P (pe, signo, detail->exc_subcode)) |
777 | { |
778 | if (pe->preemptor) |
779 | { |
780 | sighandler_t handler = (*pe->preemptor) (pe, ss, |
781 | &signo, detail); |
782 | if (handler != SIG_ERR) |
783 | return handler; |
784 | } |
785 | else |
786 | return pe->handler; |
787 | } |
788 | pe = pe->next; |
789 | } while (pe != 0); |
790 | return SIG_ERR; |
791 | } |
792 | |
793 | handler = ss->preemptors ? try_preemptor (ss->preemptors) : SIG_ERR; |
794 | |
795 | /* If no thread-specific preemptor, check for a global one. */ |
796 | if (handler == SIG_ERR && __sigismember (set: &_hurdsig_preempted_set, sig: signo)) |
797 | { |
798 | __mutex_lock (&_hurd_siglock); |
799 | handler = try_preemptor (_hurdsig_preemptors); |
800 | __mutex_unlock (&_hurd_siglock); |
801 | } |
802 | } |
803 | |
804 | ss_suspended = 0; |
805 | |
806 | if (handler == SIG_IGN) |
807 | /* Ignore the signal altogether. */ |
808 | act = ignore; |
809 | else if (handler != SIG_ERR) |
810 | { |
811 | /* Run the preemption-provided handler. */ |
812 | action = &preempt_sigaction; |
813 | act = handle; |
814 | } |
815 | else |
816 | { |
817 | /* No preemption. Do normal handling. */ |
818 | |
819 | action = & _hurd_sigstate_actions (ss) [signo]; |
820 | |
821 | if (!untraced && __sigismember (set: &_hurdsig_traced, sig: signo)) |
822 | { |
823 | /* We are being traced. Stop to tell the debugger of the signal. */ |
824 | if (_hurd_stopped) |
825 | /* Already stopped. Mark the signal as pending; |
826 | when resumed, we will notice it and stop again. */ |
827 | mark_pending (); |
828 | else |
829 | suspend (); |
830 | _hurd_sigstate_unlock (ss); |
831 | reply (); |
832 | return NULL; |
833 | } |
834 | |
835 | handler = action->sa_handler; |
836 | |
837 | if (handler == SIG_DFL) |
838 | /* Figure out the default action for this signal. */ |
839 | switch (signo) |
840 | { |
841 | case 0: |
842 | /* A sig_post msg with SIGNO==0 is sent to |
843 | tell us to check for pending signals. */ |
844 | act = ignore; |
845 | break; |
846 | |
847 | case SIGTTIN: |
848 | case SIGTTOU: |
849 | case SIGSTOP: |
850 | case SIGTSTP: |
851 | act = stop; |
852 | break; |
853 | |
854 | case SIGCONT: |
855 | case SIGIO: |
856 | case SIGURG: |
857 | case SIGCHLD: |
858 | case SIGWINCH: |
859 | act = ignore; |
860 | break; |
861 | |
862 | case SIGQUIT: |
863 | case SIGILL: |
864 | case SIGTRAP: |
865 | case SIGIOT: |
866 | case SIGEMT: |
867 | case SIGFPE: |
868 | case SIGBUS: |
869 | case SIGSEGV: |
870 | case SIGSYS: |
871 | act = core; |
872 | break; |
873 | |
874 | case SIGINFO: |
875 | if (_hurd_pgrp == _hurd_pid) |
876 | { |
877 | /* We are the process group leader. Since there is no |
878 | user-specified handler for SIGINFO, we use a default one |
879 | which prints something interesting. We use the normal |
880 | handler mechanism instead of just doing it here to avoid |
881 | the signal thread faulting or blocking in this |
882 | potentially hairy operation. */ |
883 | act = handle; |
884 | handler = _hurd_siginfo_handler; |
885 | } |
886 | else |
887 | act = ignore; |
888 | break; |
889 | |
890 | default: |
891 | act = term; |
892 | break; |
893 | } |
894 | else if (handler == SIG_IGN) |
895 | act = ignore; |
896 | else |
897 | act = handle; |
898 | |
899 | if (__sigmask (signo) & STOPSIGS) |
900 | /* Stop signals clear a pending SIGCONT even if they |
901 | are handled or ignored (but not if preempted). */ |
902 | __sigdelset (set: &ss->pending, SIGCONT); |
903 | else |
904 | { |
905 | if (signo == SIGCONT) |
906 | /* Even if handled or ignored (but not preempted), SIGCONT clears |
907 | stop signals and resumes the process. */ |
908 | ss->pending &= ~STOPSIGS; |
909 | |
910 | if (_hurd_stopped && act != stop && (untraced || signo == SIGCONT)) |
911 | resume (); |
912 | } |
913 | } |
914 | |
915 | if (_hurd_orphaned && act == stop |
916 | && (__sigmask (signo) & (__sigmask (SIGTTIN) | __sigmask (SIGTTOU) |
917 | | __sigmask (SIGTSTP)))) |
918 | { |
919 | /* If we would ordinarily stop for a job control signal, but we are |
920 | orphaned so no one would ever notice and continue us again, we just |
921 | quietly die, alone and in the dark. */ |
922 | detail->code = signo; |
923 | signo = SIGKILL; |
924 | act = term; |
925 | } |
926 | |
927 | /* Handle receipt of a blocked signal, or any signal while stopped. */ |
928 | if (__sigismember (set: &blocked, sig: signo) || (signo != SIGKILL && _hurd_stopped)) |
929 | { |
930 | mark_pending (); |
931 | act = ignore; |
932 | } |
933 | |
934 | /* Perform the chosen action for the signal. */ |
935 | switch (act) |
936 | { |
937 | case stop: |
938 | if (_hurd_stopped) |
939 | { |
940 | /* We are already stopped, but receiving an untraced stop |
941 | signal. Instead of resuming and suspending again, just |
942 | notify the proc server of the new stop signal. */ |
943 | error_t err = __USEPORT (PROC, __proc_mark_stop |
944 | (port, signo, detail->code)); |
945 | assert_perror (err); |
946 | } |
947 | else |
948 | /* Suspend the process. */ |
949 | suspend (); |
950 | break; |
951 | |
952 | case ignore: |
953 | if (detail->exc) |
954 | /* Blocking or ignoring a machine exception is fatal. |
955 | Otherwise we could just spin on the faulting instruction. */ |
956 | goto fatal; |
957 | |
958 | /* Nobody cares about this signal. If there was a call to resume |
959 | above in SIGCONT processing and we've left a thread suspended, |
960 | now's the time to set it going. */ |
961 | if (ss_suspended) |
962 | { |
963 | assert (ss->thread != MACH_PORT_NULL); |
964 | err = __thread_resume (ss->thread); |
965 | assert_perror (err); |
966 | ss_suspended = 0; |
967 | } |
968 | break; |
969 | |
970 | sigbomb: |
971 | /* We got a fault setting up the stack frame for the handler. |
972 | Nothing to do but die; BSD gets SIGILL in this case. */ |
973 | detail->code = signo; /* XXX ? */ |
974 | signo = SIGILL; |
975 | |
976 | fatal: |
977 | act = core; |
978 | /* FALLTHROUGH */ |
979 | |
980 | case term: /* Time to die. */ |
981 | case core: /* And leave a rotting corpse. */ |
982 | /* Have the proc server stop all other threads in our task. */ |
983 | err = __USEPORT (PROC, __proc_dostop (port, _hurd_msgport_thread)); |
984 | assert_perror (err); |
985 | /* No more user instructions will be executed. |
986 | The signal can now be considered delivered. */ |
987 | reply (); |
988 | /* Abort all server operations now in progress. */ |
989 | abort_all_rpcs (signo, state: &thread_state, live: 0); |
990 | |
991 | { |
992 | int status = W_EXITCODE (0, signo); |
993 | /* Do a core dump if desired. Only set the wait status bit saying we |
994 | in fact dumped core if the operation was actually successful. */ |
995 | if (act == core && write_corefile (signo, detail)) |
996 | status |= WCOREFLAG; |
997 | /* Tell proc how we died and then stick the saber in the gut. */ |
998 | _hurd_exit (status); |
999 | /* NOTREACHED */ |
1000 | } |
1001 | |
1002 | case handle: |
1003 | /* Call a handler for this signal. */ |
1004 | { |
1005 | struct sigcontext *scp, ocontext; |
1006 | int wait_for_reply, state_changed; |
1007 | |
1008 | assert (ss->thread != MACH_PORT_NULL); |
1009 | |
1010 | /* Stop the thread and abort its pending RPC operations. */ |
1011 | if (! ss_suspended) |
1012 | { |
1013 | err = __thread_suspend (ss->thread); |
1014 | assert_perror (err); |
1015 | } |
1016 | |
1017 | /* Abort the thread's kernel context, so any pending message send |
1018 | or receive completes immediately or aborts. If an interruptible |
1019 | RPC is in progress, abort_rpcs will do this. But we must always |
1020 | do it before fetching the thread's state, because |
1021 | thread_get_state is never kosher before thread_abort. */ |
1022 | abort_thread (ss, state: &thread_state, NULL); |
1023 | |
1024 | if (ss->context) |
1025 | { |
1026 | /* We have a previous sigcontext that sigreturn was about |
1027 | to restore when another signal arrived. */ |
1028 | |
1029 | mach_port_t *loc; |
1030 | |
1031 | if (_hurdsig_catch_memory_fault (ss->context)) |
1032 | { |
1033 | /* We faulted reading the thread's stack. Forget that |
1034 | context and pretend it wasn't there. It almost |
1035 | certainly crash if this handler returns, but that's it's |
1036 | problem. */ |
1037 | ss->context = NULL; |
1038 | } |
1039 | else |
1040 | { |
1041 | /* Copy the context from the thread's stack before |
1042 | we start diddling the stack to set up the handler. */ |
1043 | ocontext = *ss->context; |
1044 | ss->context = &ocontext; |
1045 | } |
1046 | _hurdsig_end_catch_fault (); |
1047 | |
1048 | if (! machine_get_basic_state (ss->thread, &thread_state)) |
1049 | goto sigbomb; |
1050 | loc = interrupted_reply_port_location (ss->thread, |
1051 | &thread_state, 1); |
1052 | if (loc && *loc != MACH_PORT_NULL) |
1053 | /* This is the reply port for the context which called |
1054 | sigreturn. Since we are abandoning that context entirely |
1055 | and restoring SS->context instead, destroy this port. */ |
1056 | __mach_port_destroy (__mach_task_self (), *loc); |
1057 | |
1058 | /* The thread was in sigreturn, not in any interruptible RPC. */ |
1059 | wait_for_reply = 0; |
1060 | |
1061 | assert (! __spin_lock_locked (&ss->critical_section_lock)); |
1062 | } |
1063 | else |
1064 | { |
1065 | int crit = __spin_lock_locked (&ss->critical_section_lock); |
1066 | |
1067 | wait_for_reply |
1068 | = (_hurdsig_abort_rpcs (ss, |
1069 | /* In a critical section, any RPC |
1070 | should be cancelled instead of |
1071 | restarted, regardless of |
1072 | SA_RESTART, so the entire |
1073 | "atomic" operation can be aborted |
1074 | as a unit. */ |
1075 | crit ? 0 : signo, 1, |
1076 | &thread_state, &state_changed, |
1077 | reply) |
1078 | != MACH_PORT_NULL); |
1079 | |
1080 | if (crit) |
1081 | { |
1082 | /* The thread is in a critical section. Mark the signal as |
1083 | pending. When it finishes the critical section, it will |
1084 | check for pending signals. */ |
1085 | mark_pending (); |
1086 | if (state_changed) |
1087 | /* Some cases of interrupting an RPC must change the |
1088 | thread state to back out the call. Normally this |
1089 | change is rolled into the warping to the handler and |
1090 | sigreturn, but we are not running the handler now |
1091 | because the thread is in a critical section. Instead, |
1092 | mutate the thread right away for the RPC interruption |
1093 | and resume it; the RPC will return early so the |
1094 | critical section can end soon. */ |
1095 | __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR, |
1096 | (natural_t *) &thread_state.basic, |
1097 | MACHINE_THREAD_STATE_COUNT); |
1098 | /* */ |
1099 | ss->intr_port = MACH_PORT_NULL; |
1100 | __thread_resume (ss->thread); |
1101 | break; |
1102 | } |
1103 | } |
1104 | |
1105 | /* Call the machine-dependent function to set the thread up |
1106 | to run the signal handler, and preserve its old context. */ |
1107 | scp = _hurd_setup_sighandler (ss, action, handler, signo, detail, |
1108 | rpc_wait: wait_for_reply, state: &thread_state); |
1109 | if (scp == NULL) |
1110 | goto sigbomb; |
1111 | |
1112 | /* Set the machine-independent parts of the signal context. */ |
1113 | |
1114 | { |
1115 | /* Fetch the thread variable for the MiG reply port, |
1116 | and set it to MACH_PORT_NULL. */ |
1117 | mach_port_t *loc = interrupted_reply_port_location (ss->thread, |
1118 | &thread_state, |
1119 | 1); |
1120 | if (loc) |
1121 | { |
1122 | scp->sc_reply_port = *loc; |
1123 | *loc = MACH_PORT_NULL; |
1124 | } |
1125 | else |
1126 | scp->sc_reply_port = MACH_PORT_NULL; |
1127 | |
1128 | /* Save the intr_port in use by the interrupted code, |
1129 | and clear the cell before running the trampoline. */ |
1130 | scp->sc_intr_port = ss->intr_port; |
1131 | ss->intr_port = MACH_PORT_NULL; |
1132 | |
1133 | if (ss->context) |
1134 | { |
1135 | /* After the handler runs we will restore to the state in |
1136 | SS->context, not the state of the thread now. So restore |
1137 | that context's reply port and intr port. */ |
1138 | |
1139 | scp->sc_reply_port = ss->context->sc_reply_port; |
1140 | scp->sc_intr_port = ss->context->sc_intr_port; |
1141 | |
1142 | ss->context = NULL; |
1143 | } |
1144 | } |
1145 | |
1146 | /* Backdoor extra argument to signal handler. */ |
1147 | scp->sc_error = detail->error; |
1148 | |
1149 | /* Block requested signals while running the handler. */ |
1150 | scp->sc_mask = ss->blocked; |
1151 | __sigorset (dest: &ss->blocked, left: &ss->blocked, right: &action->sa_mask); |
1152 | |
1153 | /* Also block SIGNO unless we're asked not to. */ |
1154 | if (! (action->sa_flags & (SA_RESETHAND | SA_NODEFER))) |
1155 | __sigaddset (set: &ss->blocked, sig: signo); |
1156 | |
1157 | /* Reset to SIG_DFL if requested. SIGILL and SIGTRAP cannot |
1158 | be automatically reset when delivered; the system silently |
1159 | enforces this restriction. */ |
1160 | if (action->sa_flags & SA_RESETHAND |
1161 | && signo != SIGILL && signo != SIGTRAP) |
1162 | action->sa_handler = SIG_DFL; |
1163 | |
1164 | /* Any sigsuspend call must return after the handler does. */ |
1165 | wake_sigsuspend (ss); |
1166 | |
1167 | /* Start the thread running the handler (or possibly waiting for an |
1168 | RPC reply before running the handler). */ |
1169 | err = __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR, |
1170 | (natural_t *) &thread_state.basic, |
1171 | MACHINE_THREAD_STATE_COUNT); |
1172 | assert_perror (err); |
1173 | err = __thread_resume (ss->thread); |
1174 | assert_perror (err); |
1175 | thread_state.set = 0; /* Everything we know is now wrong. */ |
1176 | break; |
1177 | } |
1178 | } |
1179 | |
1180 | return ss; |
1181 | } |
1182 | |
1183 | /* Return the set of pending signals in SS which should be delivered. */ |
1184 | static sigset_t |
1185 | pending_signals (struct hurd_sigstate *ss) |
1186 | { |
1187 | /* We don't worry about any pending signals if we are stopped, nor if |
1188 | SS is in a critical section. We are guaranteed to get a sig_post |
1189 | message before any of them become deliverable: either the SIGCONT |
1190 | signal, or a sig_post with SIGNO==0 as an explicit poll when the |
1191 | thread finishes its critical section. */ |
1192 | if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock)) |
1193 | return 0; |
1194 | |
1195 | return _hurd_sigstate_pending (ss) & ~ss->blocked; |
1196 | } |
1197 | |
1198 | /* Post the specified pending signals in SS and return 1. If one of |
1199 | them is traced, abort immediately and return 0. SS must be locked on |
1200 | entry and will be unlocked in all cases. */ |
1201 | static int |
1202 | post_pending (struct hurd_sigstate *ss, sigset_t pending, void (*reply) (void)) |
1203 | { |
1204 | int signo; |
1205 | struct hurd_signal_detail detail; |
1206 | |
1207 | /* Make sure SS corresponds to an actual thread, since we assume it won't |
1208 | change in post_signal. */ |
1209 | assert (ss->thread != MACH_PORT_NULL); |
1210 | |
1211 | for (signo = 1; signo < NSIG; ++signo) |
1212 | if (__sigismember (set: &pending, sig: signo)) |
1213 | { |
1214 | detail = sigstate_clear_pending (ss, signo); |
1215 | _hurd_sigstate_unlock (ss); |
1216 | |
1217 | /* Will reacquire the lock, except if the signal is traced. */ |
1218 | if (! post_signal (ss, signo, detail: &detail, untraced: 0, reply)) |
1219 | return 0; |
1220 | } |
1221 | |
1222 | /* No more signals pending; SS->lock is still locked. */ |
1223 | _hurd_sigstate_unlock (ss); |
1224 | |
1225 | return 1; |
1226 | } |
1227 | |
1228 | /* Post all the pending signals of all threads and return 1. If a traced |
1229 | signal is encountered, abort immediately and return 0. */ |
1230 | static int |
1231 | post_all_pending_signals (void (*reply) (void)) |
1232 | { |
1233 | struct hurd_sigstate *ss; |
1234 | sigset_t pending = 0; |
1235 | |
1236 | for (;;) |
1237 | { |
1238 | __mutex_lock (&_hurd_siglock); |
1239 | for (ss = _hurd_sigstates; ss != NULL; ss = ss->next) |
1240 | { |
1241 | _hurd_sigstate_lock (ss); |
1242 | |
1243 | pending = pending_signals (ss); |
1244 | if (pending) |
1245 | /* post_pending() below will unlock SS. */ |
1246 | break; |
1247 | |
1248 | _hurd_sigstate_unlock (ss); |
1249 | } |
1250 | __mutex_unlock (&_hurd_siglock); |
1251 | |
1252 | if (! pending) |
1253 | return 1; |
1254 | if (! post_pending (ss, pending, reply)) |
1255 | return 0; |
1256 | } |
1257 | } |
1258 | |
1259 | /* Deliver a signal. SS is not locked. */ |
1260 | void |
1261 | _hurd_internal_post_signal (struct hurd_sigstate *ss, |
1262 | int signo, struct hurd_signal_detail *detail, |
1263 | mach_port_t reply_port, |
1264 | mach_msg_type_name_t reply_port_type, |
1265 | int untraced) |
1266 | { |
1267 | /* Reply to this sig_post message. */ |
1268 | __typeof (__msg_sig_post_reply) *reply_rpc |
1269 | = (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply); |
1270 | void reply (void) |
1271 | { |
1272 | error_t err; |
1273 | if (reply_port == MACH_PORT_NULL) |
1274 | return; |
1275 | err = (*reply_rpc) (reply_port, reply_port_type, 0); |
1276 | reply_port = MACH_PORT_NULL; |
1277 | if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port. */ |
1278 | assert_perror (err); |
1279 | } |
1280 | |
1281 | ss = post_signal (ss, signo, detail, untraced, reply); |
1282 | if (! ss) |
1283 | return; |
1284 | |
1285 | /* The signal was neither fatal nor traced. We still hold SS->lock. */ |
1286 | if (signo != 0 && ss->thread != MACH_PORT_NULL) |
1287 | { |
1288 | /* The signal has either been ignored or is now being handled. We can |
1289 | consider it delivered and reply to the killer. */ |
1290 | reply (); |
1291 | |
1292 | /* Post any pending signals for this thread. */ |
1293 | if (! post_pending (ss, pending: pending_signals (ss), reply)) |
1294 | return; |
1295 | } |
1296 | else |
1297 | { |
1298 | /* If this was a process-wide signal or a poll request, we need |
1299 | to check for pending signals for all threads. */ |
1300 | _hurd_sigstate_unlock (ss); |
1301 | if (! post_all_pending_signals (reply)) |
1302 | return; |
1303 | |
1304 | /* All pending signals delivered to all threads. |
1305 | Now we can send the reply message even for signal 0. */ |
1306 | reply (); |
1307 | } |
1308 | } |
1309 | |
1310 | /* Decide whether REFPORT enables the sender to send us a SIGNO signal. |
1311 | Returns zero if so, otherwise the error code to return to the sender. */ |
1312 | |
1313 | static error_t |
1314 | signal_allowed (int signo, mach_port_t refport) |
1315 | { |
1316 | if (signo < 0 || signo >= NSIG) |
1317 | return EINVAL; |
1318 | |
1319 | if (refport == __mach_task_self ()) |
1320 | /* Can send any signal. */ |
1321 | goto win; |
1322 | |
1323 | /* Avoid needing to check for this below. */ |
1324 | if (refport == MACH_PORT_NULL) |
1325 | return EPERM; |
1326 | |
1327 | switch (signo) |
1328 | { |
1329 | case SIGINT: |
1330 | case SIGQUIT: |
1331 | case SIGTSTP: |
1332 | case SIGHUP: |
1333 | case SIGINFO: |
1334 | case SIGTTIN: |
1335 | case SIGTTOU: |
1336 | case SIGWINCH: |
1337 | /* Job control signals can be sent by the controlling terminal. */ |
1338 | if (__USEPORT (CTTYID, port == refport)) |
1339 | goto win; |
1340 | break; |
1341 | |
1342 | case SIGCONT: |
1343 | { |
1344 | /* A continue signal can be sent by anyone in the session. */ |
1345 | mach_port_t sessport; |
1346 | if (! __USEPORT (PROC, __proc_getsidport (port, &sessport))) |
1347 | { |
1348 | __mach_port_deallocate (__mach_task_self (), sessport); |
1349 | if (refport == sessport) |
1350 | goto win; |
1351 | } |
1352 | } |
1353 | break; |
1354 | |
1355 | case SIGIO: |
1356 | case SIGURG: |
1357 | { |
1358 | /* Any io object a file descriptor refers to might send us |
1359 | one of these signals using its async ID port for REFPORT. |
1360 | |
1361 | This is pretty wide open; it is not unlikely that some random |
1362 | process can at least open for reading something we have open, |
1363 | get its async ID port, and send us a spurious SIGIO or SIGURG |
1364 | signal. But BSD is actually wider open than that!--you can set |
1365 | the owner of an io object to any process or process group |
1366 | whatsoever and send them gratuitous signals. |
1367 | |
1368 | Someday we could implement some reasonable scheme for |
1369 | authorizing SIGIO and SIGURG signals properly. */ |
1370 | |
1371 | int d; |
1372 | int lucky = 0; /* True if we find a match for REFPORT. */ |
1373 | __mutex_lock (&_hurd_dtable_lock); |
1374 | for (d = 0; !lucky && (unsigned) d < (unsigned) _hurd_dtablesize; ++d) |
1375 | { |
1376 | struct hurd_userlink ulink; |
1377 | io_t port; |
1378 | mach_port_t asyncid; |
1379 | if (_hurd_dtable[d] == NULL) |
1380 | continue; |
1381 | port = _hurd_port_get (&_hurd_dtable[d]->port, &ulink); |
1382 | if (! __io_get_icky_async_id (port, &asyncid)) |
1383 | { |
1384 | if (refport == asyncid) |
1385 | /* Break out of the loop on the next iteration. */ |
1386 | lucky = 1; |
1387 | __mach_port_deallocate (__mach_task_self (), asyncid); |
1388 | } |
1389 | _hurd_port_free (&_hurd_dtable[d]->port, &ulink, port); |
1390 | } |
1391 | __mutex_unlock (&_hurd_dtable_lock); |
1392 | /* If we found a lucky winner, we've set D to -1 in the loop. */ |
1393 | if (lucky) |
1394 | goto win; |
1395 | } |
1396 | } |
1397 | |
1398 | /* If this signal is legit, we have done `goto win' by now. |
1399 | When we return the error, mig deallocates REFPORT. */ |
1400 | return EPERM; |
1401 | |
1402 | win: |
1403 | /* Deallocate the REFPORT send right; we are done with it. */ |
1404 | __mach_port_deallocate (__mach_task_self (), refport); |
1405 | |
1406 | return 0; |
1407 | } |
1408 | |
1409 | /* Implement the sig_post RPC from <hurd/msg.defs>; |
1410 | sent when someone wants us to get a signal. */ |
1411 | kern_return_t |
1412 | _S_msg_sig_post (mach_port_t me, |
1413 | mach_port_t reply_port, mach_msg_type_name_t reply_port_type, |
1414 | int signo, natural_t sigcode, |
1415 | mach_port_t refport) |
1416 | { |
1417 | error_t err; |
1418 | struct hurd_signal_detail d; |
1419 | |
1420 | if (err = signal_allowed (signo, refport)) |
1421 | return err; |
1422 | |
1423 | d.code = d.exc_subcode = sigcode; |
1424 | d.exc = 0; |
1425 | |
1426 | /* Post the signal to a global receiver thread (or mark it pending in |
1427 | the global sigstate). This will reply when the signal can be |
1428 | considered delivered. */ |
1429 | _hurd_internal_post_signal (_hurd_global_sigstate, |
1430 | signo, &d, reply_port, reply_port_type, |
1431 | 0); /* Stop if traced. */ |
1432 | |
1433 | return MIG_NO_REPLY; /* Already replied. */ |
1434 | } |
1435 | |
1436 | /* Implement the sig_post_untraced RPC from <hurd/msg.defs>; |
1437 | sent when the debugger wants us to really get a signal |
1438 | even if we are traced. */ |
1439 | kern_return_t |
1440 | _S_msg_sig_post_untraced (mach_port_t me, |
1441 | mach_port_t reply_port, |
1442 | mach_msg_type_name_t reply_port_type, |
1443 | int signo, natural_t sigcode, |
1444 | mach_port_t refport) |
1445 | { |
1446 | error_t err; |
1447 | struct hurd_signal_detail d; |
1448 | |
1449 | if (err = signal_allowed (signo, refport)) |
1450 | return err; |
1451 | |
1452 | d.code = d.exc_subcode = sigcode; |
1453 | d.exc = 0; |
1454 | |
1455 | /* Post the signal to the designated signal-receiving thread. This will |
1456 | reply when the signal can be considered delivered. */ |
1457 | _hurd_internal_post_signal (_hurd_global_sigstate, |
1458 | signo, &d, reply_port, reply_port_type, |
1459 | 1); /* Untraced flag. */ |
1460 | |
1461 | return MIG_NO_REPLY; /* Already replied. */ |
1462 | } |
1463 | |
1464 | extern void __mig_init (void *); |
1465 | |
1466 | #include <mach/task_special_ports.h> |
1467 | |
1468 | /* Initialize the message port, _hurd_global_sigstate, and start the |
1469 | signal thread. */ |
1470 | |
1471 | void |
1472 | _hurdsig_init (const int *intarray, size_t intarraysize) |
1473 | { |
1474 | error_t err; |
1475 | vm_size_t stacksize; |
1476 | struct hurd_sigstate *ss; |
1477 | |
1478 | __mutex_init (&_hurd_siglock); |
1479 | |
1480 | err = __mach_port_allocate (__mach_task_self (), |
1481 | MACH_PORT_RIGHT_RECEIVE, |
1482 | &_hurd_msgport); |
1483 | assert_perror (err); |
1484 | |
1485 | /* Make a send right to the signal port. */ |
1486 | err = __mach_port_insert_right (__mach_task_self (), |
1487 | _hurd_msgport, |
1488 | _hurd_msgport, |
1489 | MACH_MSG_TYPE_MAKE_SEND); |
1490 | assert_perror (err); |
1491 | |
1492 | /* Initialize the global signal state. */ |
1493 | _hurd_global_sigstate = _hurd_thread_sigstate (MACH_PORT_NULL); |
1494 | |
1495 | /* We block all signals, and let actual threads pull them from the |
1496 | pending mask. */ |
1497 | __sigfillset(set: & _hurd_global_sigstate->blocked); |
1498 | |
1499 | /* Initialize the main thread's signal state. */ |
1500 | ss = _hurd_self_sigstate (); |
1501 | |
1502 | /* Mark it as a process-wide signal receiver. Threads in this set use |
1503 | the common action vector in _hurd_global_sigstate. */ |
1504 | _hurd_sigstate_set_global_rcv (ss); |
1505 | |
1506 | /* Copy inherited signal settings from our parent (or pre-exec process |
1507 | state) */ |
1508 | if (intarraysize > INIT_SIGMASK) |
1509 | ss->blocked = intarray[INIT_SIGMASK]; |
1510 | if (intarraysize > INIT_SIGPENDING) |
1511 | _hurd_global_sigstate->pending = intarray[INIT_SIGPENDING]; |
1512 | if (intarraysize > INIT_SIGIGN && intarray[INIT_SIGIGN] != 0) |
1513 | { |
1514 | int signo; |
1515 | for (signo = 1; signo < NSIG; ++signo) |
1516 | if (intarray[INIT_SIGIGN] & __sigmask(signo)) |
1517 | _hurd_global_sigstate->actions[signo].sa_handler = SIG_IGN; |
1518 | } |
1519 | |
1520 | /* Start the signal thread listening on the message port. */ |
1521 | |
1522 | #pragma weak __pthread_create |
1523 | if (!__pthread_create) |
1524 | { |
1525 | err = __thread_create (__mach_task_self (), &_hurd_msgport_thread); |
1526 | assert_perror (err); |
1527 | |
1528 | stacksize = __vm_page_size * 8; /* Small stack for signal thread. */ |
1529 | err = __mach_setup_thread_call (__mach_task_self (), |
1530 | _hurd_msgport_thread, |
1531 | _hurd_msgport_receive, |
1532 | (vm_address_t *) &__hurd_sigthread_stack_base, |
1533 | &stacksize); |
1534 | assert_perror (err); |
1535 | err = __mach_setup_tls (_hurd_msgport_thread); |
1536 | assert_perror (err); |
1537 | |
1538 | __hurd_sigthread_stack_end = __hurd_sigthread_stack_base + stacksize; |
1539 | |
1540 | /* Reinitialize the MiG support routines so they will use a per-thread |
1541 | variable for the cached reply port. */ |
1542 | __mig_init ((void *) __hurd_sigthread_stack_base); |
1543 | |
1544 | err = __thread_resume (_hurd_msgport_thread); |
1545 | assert_perror (err); |
1546 | } |
1547 | else |
1548 | { |
1549 | pthread_t thread; |
1550 | pthread_attr_t attr; |
1551 | void *addr; |
1552 | size_t size; |
1553 | |
1554 | /* When pthread is being used, we need to make the signal thread a |
1555 | proper pthread. Otherwise it cannot use mutex_lock et al, which |
1556 | will be the pthread versions. Various of the message port RPC |
1557 | handlers need to take locks, so we need to be able to call into |
1558 | pthread code and meet its assumptions about how our thread and |
1559 | its stack are arranged. Since pthread puts it there anyway, |
1560 | we'll let the signal thread's per-thread variables be found as for |
1561 | any normal pthread, and just leave the magic __hurd_sigthread_* |
1562 | values all zero so they'll be ignored. */ |
1563 | |
1564 | #pragma weak __pthread_detach |
1565 | #pragma weak __pthread_getattr_np |
1566 | #pragma weak __pthread_attr_getstack |
1567 | __pthread_create(newthread: &thread, NULL, start_routine: &_hurd_msgport_receive, NULL); |
1568 | |
1569 | /* Record signal thread stack layout for fork() */ |
1570 | __pthread_getattr_np (thread, &attr); |
1571 | __pthread_attr_getstack (attr: &attr, stackaddr: &addr, stacksize: &size); |
1572 | __hurd_sigthread_stack_base = (uintptr_t) addr; |
1573 | __hurd_sigthread_stack_end = __hurd_sigthread_stack_base + size; |
1574 | |
1575 | __pthread_detach(th: thread); |
1576 | |
1577 | /* XXX We need the thread port for the signal thread further on |
1578 | in this thread (see hurdfault.c:_hurdsigfault_init). |
1579 | Therefore we block until _hurd_msgport_thread is initialized |
1580 | by the newly created thread. This really shouldn't be |
1581 | necessary; we should be able to fetch the thread port for a |
1582 | pthread from here. */ |
1583 | while (_hurd_msgport_thread == 0) |
1584 | __swtch_pri (0); |
1585 | } |
1586 | |
1587 | /* Receive exceptions on the signal port. */ |
1588 | #ifdef TASK_EXCEPTION_PORT |
1589 | __task_set_special_port (__mach_task_self (), |
1590 | TASK_EXCEPTION_PORT, _hurd_msgport); |
1591 | #elif defined (EXC_MASK_ALL) |
1592 | __task_set_exception_ports (__mach_task_self (), |
1593 | EXC_MASK_ALL & ~(EXC_MASK_SYSCALL |
1594 | | EXC_MASK_MACH_SYSCALL |
1595 | | EXC_MASK_RPC_ALERT), |
1596 | _hurd_msgport, |
1597 | EXCEPTION_DEFAULT, MACHINE_THREAD_STATE); |
1598 | #else |
1599 | # error task_set_exception_port? |
1600 | #endif |
1601 | |
1602 | /* Sanity check. Any pending, unblocked signals should have been |
1603 | taken by our predecessor incarnation (i.e. parent or pre-exec state) |
1604 | before packing up our init ints. This assert is last (not above) |
1605 | so that signal handling is all set up to handle the abort. */ |
1606 | assert ((ss->pending &~ ss->blocked) == 0); |
1607 | } |
1608 | /* XXXX */ |
1609 | /* Reauthenticate with the proc server. */ |
1610 | |
1611 | static void |
1612 | reauth_proc (mach_port_t new) |
1613 | { |
1614 | mach_port_t ref, ignore; |
1615 | |
1616 | ref = __mach_reply_port (); |
1617 | if (! HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC], |
1618 | __proc_reauthenticate (port, ref, |
1619 | MACH_MSG_TYPE_MAKE_SEND) |
1620 | || __auth_user_authenticate (new, ref, |
1621 | MACH_MSG_TYPE_MAKE_SEND, |
1622 | &ignore)) |
1623 | && ignore != MACH_PORT_NULL) |
1624 | __mach_port_deallocate (__mach_task_self (), ignore); |
1625 | __mach_port_destroy (__mach_task_self (), ref); |
1626 | |
1627 | /* Set the owner of the process here too. */ |
1628 | __mutex_lock (&_hurd_id.lock); |
1629 | if (!_hurd_check_ids ()) |
1630 | HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC], |
1631 | __proc_setowner (port, |
1632 | (_hurd_id.gen.nuids |
1633 | ? _hurd_id.gen.uids[0] : 0), |
1634 | !_hurd_id.gen.nuids)); |
1635 | __mutex_unlock (&_hurd_id.lock); |
1636 | |
1637 | (void) &reauth_proc; /* Silence compiler warning. */ |
1638 | } |
1639 | text_set_element (_hurd_reauth_hook, reauth_proc); |
1640 | |
1641 | /* Like `getenv', but safe for the signal thread to run. |
1642 | If the environment is trashed, this will just return NULL. */ |
1643 | |
1644 | const char * |
1645 | _hurdsig_getenv (const char *variable) |
1646 | { |
1647 | if (__libc_enable_secure) |
1648 | return NULL; |
1649 | |
1650 | if (_hurdsig_catch_memory_fault (__environ)) |
1651 | /* We bombed in getenv. */ |
1652 | return NULL; |
1653 | else |
1654 | { |
1655 | const size_t len = strlen (s: variable); |
1656 | char *value = NULL; |
1657 | char *volatile *ep = __environ; |
1658 | while (*ep) |
1659 | { |
1660 | const char *p = *ep; |
1661 | _hurdsig_fault_preemptor.first = (long int) p; |
1662 | _hurdsig_fault_preemptor.last = VM_MAX_ADDRESS; |
1663 | if (! strncmp (s1: p, s2: variable, n: len) && p[len] == '=') |
1664 | { |
1665 | size_t valuelen; |
1666 | p += len + 1; |
1667 | valuelen = strlen (s: p); |
1668 | _hurdsig_fault_preemptor.last = (long int) (p + valuelen); |
1669 | value = malloc (++valuelen); |
1670 | if (value) |
1671 | memcpy (dest: value, src: p, n: valuelen); |
1672 | break; |
1673 | } |
1674 | _hurdsig_fault_preemptor.first = (long int) ++ep; |
1675 | _hurdsig_fault_preemptor.last = (long int) (ep + 1); |
1676 | } |
1677 | _hurdsig_end_catch_fault (); |
1678 | return value; |
1679 | } |
1680 | } |
1681 | |