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7f513ec8 | 1 | /* Copyright (C) 1994,1995,1996,1997,1999,2001,2002,2004,2005,2006,2011 |
8f480b4b | 2 | Free Software Foundation, Inc. |
478b92f0 | 3 | This file is part of the GNU C Library. |
28f540f4 | 4 | |
478b92f0 | 5 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
28f540f4 | 9 | |
478b92f0 UD |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
28f540f4 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 RM |
18 | |
19 | #include <errno.h> | |
20 | #include <unistd.h> | |
21 | #include <hurd.h> | |
22 | #include <hurd/signal.h> | |
23 | #include <setjmp.h> | |
8f480b4b | 24 | #include <thread_state.h> |
28f540f4 RM |
25 | #include <sysdep.h> /* For stack growth direction. */ |
26 | #include "set-hooks.h" | |
27 | #include <assert.h> | |
28 | #include "hurdmalloc.h" /* XXX */ | |
3ba7b383 | 29 | #include <tls.h> |
28f540f4 | 30 | |
6b87a564 UD |
31 | #undef __fork |
32 | ||
28f540f4 RM |
33 | |
34 | /* Things that want to be locked while forking. */ | |
3fe9de0d | 35 | symbol_set_declare (_hurd_fork_locks) |
28f540f4 RM |
36 | |
37 | ||
38 | /* Things that want to be called before we fork, to prepare the parent for | |
39 | task_create, when the new child task will inherit our address space. */ | |
40 | DEFINE_HOOK (_hurd_fork_prepare_hook, (void)); | |
41 | ||
42 | /* Things that want to be called when we are forking, with the above all | |
43 | locked. They are passed the task port of the child. The child process | |
44 | is all set up except for doing proc_child, and has no threads yet. */ | |
45 | DEFINE_HOOK (_hurd_fork_setup_hook, (void)); | |
46 | ||
47 | /* Things to be run in the child fork. */ | |
48 | DEFINE_HOOK (_hurd_fork_child_hook, (void)); | |
49 | ||
50 | /* Things to be run in the parent fork. */ | |
51 | DEFINE_HOOK (_hurd_fork_parent_hook, (void)); | |
52 | ||
53 | ||
54 | /* Clone the calling process, creating an exact copy. | |
55 | Return -1 for errors, 0 to the new process, | |
56 | and the process ID of the new process to the old process. */ | |
57 | pid_t | |
58 | __fork (void) | |
59 | { | |
60 | jmp_buf env; | |
61 | pid_t pid; | |
62 | size_t i; | |
63 | error_t err; | |
28f540f4 | 64 | struct hurd_sigstate *volatile ss; |
28f540f4 RM |
65 | |
66 | ss = _hurd_self_sigstate (); | |
8f0c527e | 67 | __spin_lock (&ss->critical_section_lock); |
11872325 RM |
68 | |
69 | #undef LOSE | |
221dc560 | 70 | #define LOSE do { assert_perror (err); goto lose; } while (0) /* XXX */ |
28f540f4 RM |
71 | |
72 | if (! setjmp (env)) | |
73 | { | |
74 | process_t newproc; | |
75 | task_t newtask; | |
76 | thread_t thread, sigthread; | |
77 | mach_port_urefs_t thread_refs, sigthread_refs; | |
78 | struct machine_thread_state state; | |
79 | mach_msg_type_number_t statecount; | |
80 | mach_port_t *portnames = NULL; | |
81 | mach_msg_type_number_t nportnames = 0; | |
82 | mach_port_type_t *porttypes = NULL; | |
83 | mach_msg_type_number_t nporttypes = 0; | |
84 | thread_t *threads = NULL; | |
85 | mach_msg_type_number_t nthreads = 0; | |
3fe9de0d RM |
86 | int ports_locked = 0, stopped = 0; |
87 | ||
88 | void resume_threads (void) | |
89 | { | |
90 | if (! stopped) | |
91 | return; | |
92 | ||
93 | assert (threads); | |
94 | ||
95 | for (i = 0; i < nthreads; ++i) | |
96 | if (threads[i] != ss->thread) | |
97 | __thread_resume (threads[i]); | |
98 | stopped = 0; | |
99 | } | |
28f540f4 RM |
100 | |
101 | /* Run things that prepare for forking before we create the task. */ | |
102 | RUN_HOOK (_hurd_fork_prepare_hook, ()); | |
103 | ||
104 | /* Lock things that want to be locked before we fork. */ | |
3fe9de0d RM |
105 | { |
106 | void *const *p; | |
107 | for (p = symbol_set_first_element (_hurd_fork_locks); | |
108 | ! symbol_set_end_p (_hurd_fork_locks, p); | |
109 | ++p) | |
110 | __mutex_lock (*p); | |
111 | } | |
11872325 | 112 | __mutex_lock (&_hurd_siglock); |
e3fa2641 | 113 | |
28f540f4 RM |
114 | newtask = MACH_PORT_NULL; |
115 | thread = sigthread = MACH_PORT_NULL; | |
116 | newproc = MACH_PORT_NULL; | |
117 | ||
118 | /* Lock all the port cells for the standard ports while we copy the | |
119 | address space. We want to insert all the send rights into the | |
120 | child with the same names. */ | |
121 | for (i = 0; i < _hurd_nports; ++i) | |
122 | __spin_lock (&_hurd_ports[i].lock); | |
123 | ports_locked = 1; | |
124 | ||
e3fa2641 | 125 | |
3fe9de0d RM |
126 | /* Stop all other threads while copying the address space, |
127 | so nothing changes. */ | |
128 | err = __proc_dostop (_hurd_ports[INIT_PORT_PROC].port, ss->thread); | |
129 | if (!err) | |
478b92f0 UD |
130 | { |
131 | stopped = 1; | |
3fe9de0d | 132 | |
6df1b247 RM |
133 | #define XXX_KERNEL_PAGE_FAULT_BUG /* XXX work around page fault bug in mk */ |
134 | ||
135 | #ifdef XXX_KERNEL_PAGE_FAULT_BUG | |
136 | /* Gag me with a pitchfork. | |
137 | The bug scenario is this: | |
138 | ||
139 | - The page containing __mach_task_self_ is paged out. | |
140 | - The signal thread was faulting on that page when we | |
141 | suspended it via proc_dostop. It holds some lock, or set | |
142 | some busy bit, or somesuch. | |
143 | - Now this thread faults on that same page. | |
144 | - GRATUIOUS DEADLOCK | |
145 | ||
146 | We can break the deadlock by aborting the thread that faulted | |
147 | first, which if the bug happened was the signal thread because | |
148 | it is the only other thread and we just suspended it. | |
149 | */ | |
150 | __thread_abort (_hurd_msgport_thread); | |
151 | #endif | |
3fe9de0d | 152 | /* Create the child task. It will inherit a copy of our memory. */ |
7595ddb8 RM |
153 | err = __task_create (__mach_task_self (), |
154 | #ifdef KERN_INVALID_LEDGER | |
155 | NULL, 0, /* OSF Mach */ | |
156 | #endif | |
157 | 1, &newtask); | |
478b92f0 | 158 | } |
11872325 RM |
159 | |
160 | /* Unlock the global signal state lock, so we do not | |
161 | block the signal thread any longer than necessary. */ | |
162 | __mutex_unlock (&_hurd_siglock); | |
163 | ||
164 | if (err) | |
165 | LOSE; | |
28f540f4 RM |
166 | |
167 | /* Fetch the names of all ports used in this task. */ | |
168 | if (err = __mach_port_names (__mach_task_self (), | |
169 | &portnames, &nportnames, | |
170 | &porttypes, &nporttypes)) | |
11872325 | 171 | LOSE; |
28f540f4 RM |
172 | if (nportnames != nporttypes) |
173 | { | |
174 | err = EGRATUITOUS; | |
11872325 | 175 | LOSE; |
28f540f4 RM |
176 | } |
177 | ||
178 | /* Get send rights for all the threads in this task. | |
179 | We want to avoid giving these rights to the child. */ | |
180 | if (err = __task_threads (__mach_task_self (), &threads, &nthreads)) | |
11872325 | 181 | LOSE; |
28f540f4 RM |
182 | |
183 | /* Get the child process's proc server port. We will insert it into | |
184 | the child with the same name as we use for our own proc server | |
185 | port; and we will need it to set the child's message port. */ | |
186 | if (err = __proc_task2proc (_hurd_ports[INIT_PORT_PROC].port, | |
187 | newtask, &newproc)) | |
11872325 | 188 | LOSE; |
28f540f4 RM |
189 | |
190 | /* Insert all our port rights into the child task. */ | |
191 | thread_refs = sigthread_refs = 0; | |
192 | for (i = 0; i < nportnames; ++i) | |
193 | { | |
194 | if (porttypes[i] & MACH_PORT_TYPE_RECEIVE) | |
195 | { | |
196 | /* This is a receive right. We want to give the child task | |
197 | its own new receive right under the same name. */ | |
198 | err = __mach_port_allocate_name (newtask, | |
199 | MACH_PORT_RIGHT_RECEIVE, | |
200 | portnames[i]); | |
201 | if (err == KERN_NAME_EXISTS) | |
202 | { | |
203 | /* It already has a right under this name (?!). Well, | |
204 | there is this bizarre old Mach IPC feature (in #ifdef | |
205 | MACH_IPC_COMPAT in the ukernel) which results in new | |
206 | tasks getting a new receive right for task special | |
207 | port number 2. What else might be going on I'm not | |
208 | sure. So let's check. */ | |
209 | #if !MACH_IPC_COMPAT | |
210 | #define TASK_NOTIFY_PORT 2 | |
211 | #endif | |
212 | assert (({ mach_port_t thisport, notify_port; | |
213 | mach_msg_type_name_t poly; | |
214 | (__task_get_special_port (newtask, | |
215 | TASK_NOTIFY_PORT, | |
216 | ¬ify_port) == 0 && | |
e3fa2641 | 217 | __mach_port_extract_right |
28f540f4 RM |
218 | (newtask, |
219 | portnames[i], | |
220 | MACH_MSG_TYPE_MAKE_SEND, | |
221 | &thisport, &poly) == 0 && | |
222 | (thisport == notify_port) && | |
223 | __mach_port_deallocate (__mach_task_self (), | |
224 | thisport) == 0 && | |
225 | __mach_port_deallocate (__mach_task_self (), | |
226 | notify_port) == 0); | |
227 | })); | |
228 | } | |
229 | else if (err) | |
11872325 | 230 | LOSE; |
28f540f4 RM |
231 | if (porttypes[i] & MACH_PORT_TYPE_SEND) |
232 | { | |
233 | /* Give the child as many send rights for its receive | |
234 | right as we have for ours. */ | |
235 | mach_port_urefs_t refs; | |
236 | mach_port_t port; | |
237 | mach_msg_type_name_t poly; | |
238 | if (err = __mach_port_get_refs (__mach_task_self (), | |
239 | portnames[i], | |
240 | MACH_PORT_RIGHT_SEND, | |
241 | &refs)) | |
11872325 | 242 | LOSE; |
28f540f4 RM |
243 | if (err = __mach_port_extract_right (newtask, |
244 | portnames[i], | |
245 | MACH_MSG_TYPE_MAKE_SEND, | |
246 | &port, &poly)) | |
11872325 | 247 | LOSE; |
28f540f4 RM |
248 | if (portnames[i] == _hurd_msgport) |
249 | { | |
250 | /* We just created a receive right for the child's | |
251 | message port and are about to insert send rights | |
252 | for it. Now, while we happen to have a send right | |
253 | for it, give it to the proc server. */ | |
254 | mach_port_t old; | |
255 | if (err = __proc_setmsgport (newproc, port, &old)) | |
11872325 | 256 | LOSE; |
28f540f4 RM |
257 | if (old != MACH_PORT_NULL) |
258 | /* XXX what to do here? */ | |
259 | __mach_port_deallocate (__mach_task_self (), old); | |
4ca84cff RM |
260 | /* The new task will receive its own exceptions |
261 | on its message port. */ | |
7595ddb8 RM |
262 | if (err = |
263 | #ifdef TASK_EXCEPTION_PORT | |
264 | __task_set_special_port (newtask, | |
265 | TASK_EXCEPTION_PORT, | |
266 | port) | |
267 | #elif defined (EXC_MASK_ALL) | |
268 | __task_set_exception_ports | |
269 | (newtask, EXC_MASK_ALL & ~(EXC_MASK_SYSCALL | |
270 | | EXC_MASK_MACH_SYSCALL | |
271 | | EXC_MASK_RPC_ALERT), | |
272 | port, EXCEPTION_DEFAULT, MACHINE_THREAD_STATE) | |
273 | #else | |
274 | # error task_set_exception_port? | |
275 | #endif | |
276 | ) | |
4ca84cff | 277 | LOSE; |
28f540f4 RM |
278 | } |
279 | if (err = __mach_port_insert_right (newtask, | |
280 | portnames[i], | |
281 | port, | |
282 | MACH_MSG_TYPE_MOVE_SEND)) | |
11872325 | 283 | LOSE; |
28f540f4 RM |
284 | if (refs > 1 && |
285 | (err = __mach_port_mod_refs (newtask, | |
286 | portnames[i], | |
287 | MACH_PORT_RIGHT_SEND, | |
288 | refs - 1))) | |
11872325 | 289 | LOSE; |
28f540f4 RM |
290 | } |
291 | if (porttypes[i] & MACH_PORT_TYPE_SEND_ONCE) | |
292 | { | |
293 | /* Give the child a send-once right for its receive right, | |
294 | since we have one for ours. */ | |
295 | mach_port_t port; | |
296 | mach_msg_type_name_t poly; | |
297 | if (err = __mach_port_extract_right | |
298 | (newtask, | |
299 | portnames[i], | |
300 | MACH_MSG_TYPE_MAKE_SEND_ONCE, | |
301 | &port, &poly)) | |
11872325 | 302 | LOSE; |
28f540f4 RM |
303 | if (err = __mach_port_insert_right |
304 | (newtask, | |
305 | portnames[i], port, | |
306 | MACH_MSG_TYPE_MOVE_SEND_ONCE)) | |
11872325 | 307 | LOSE; |
28f540f4 RM |
308 | } |
309 | } | |
11872325 RM |
310 | else if (porttypes[i] & |
311 | (MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_DEAD_NAME)) | |
28f540f4 RM |
312 | { |
313 | /* This is a send right or a dead name. | |
314 | Give the child as many references for it as we have. */ | |
7f513ec8 | 315 | mach_port_urefs_t refs = 0, *record_refs = NULL; |
28f540f4 | 316 | mach_port_t insert; |
3125073e | 317 | mach_msg_type_name_t insert_type = MACH_MSG_TYPE_COPY_SEND; |
7119ea6d RM |
318 | if (portnames[i] == newtask || portnames[i] == newproc) |
319 | /* Skip the name we use for the child's task or proc ports. */ | |
28f540f4 RM |
320 | continue; |
321 | if (portnames[i] == __mach_task_self ()) | |
322 | /* For the name we use for our own task port, | |
323 | insert the child's task port instead. */ | |
324 | insert = newtask; | |
325 | else if (portnames[i] == _hurd_ports[INIT_PORT_PROC].port) | |
326 | { | |
7119ea6d RM |
327 | /* Use the proc server port for the new task. */ |
328 | insert = newproc; | |
329 | insert_type = MACH_MSG_TYPE_COPY_SEND; | |
28f540f4 | 330 | } |
3fe9de0d | 331 | else if (portnames[i] == ss->thread) |
28f540f4 RM |
332 | { |
333 | /* For the name we use for our own thread port, we will | |
334 | insert the thread port for the child main user thread | |
335 | after we create it. */ | |
336 | insert = MACH_PORT_NULL; | |
337 | record_refs = &thread_refs; | |
338 | /* Allocate a dead name right for this name as a | |
478b92f0 UD |
339 | placeholder, so the kernel will not chose this name |
340 | for any other new port (it might use it for one of the | |
341 | rights created when a thread is created). */ | |
28f540f4 RM |
342 | if (err = __mach_port_allocate_name |
343 | (newtask, MACH_PORT_RIGHT_DEAD_NAME, portnames[i])) | |
11872325 | 344 | LOSE; |
28f540f4 RM |
345 | } |
346 | else if (portnames[i] == _hurd_msgport_thread) | |
347 | /* For the name we use for our signal thread's thread port, | |
348 | we will insert the thread port for the child's signal | |
349 | thread after we create it. */ | |
350 | { | |
351 | insert = MACH_PORT_NULL; | |
352 | record_refs = &sigthread_refs; | |
353 | /* Allocate a dead name right as a placeholder. */ | |
354 | if (err = __mach_port_allocate_name | |
355 | (newtask, MACH_PORT_RIGHT_DEAD_NAME, portnames[i])) | |
11872325 | 356 | LOSE; |
28f540f4 RM |
357 | } |
358 | else | |
359 | { | |
360 | /* Skip the name we use for any of our own thread ports. */ | |
361 | mach_msg_type_number_t j; | |
362 | for (j = 0; j < nthreads; ++j) | |
363 | if (portnames[i] == threads[j]) | |
364 | break; | |
365 | if (j < nthreads) | |
366 | continue; | |
367 | ||
3125073e | 368 | /* Copy our own send right. */ |
28f540f4 RM |
369 | insert = portnames[i]; |
370 | } | |
371 | /* Find out how many user references we have for | |
372 | the send right with this name. */ | |
373 | if (err = __mach_port_get_refs (__mach_task_self (), | |
374 | portnames[i], | |
375 | MACH_PORT_RIGHT_SEND, | |
376 | record_refs ?: &refs)) | |
11872325 | 377 | LOSE; |
28f540f4 RM |
378 | if (insert == MACH_PORT_NULL) |
379 | continue; | |
11872325 RM |
380 | if (insert == portnames[i] && |
381 | (porttypes[i] & MACH_PORT_TYPE_DEAD_NAME)) | |
382 | /* This is a dead name; allocate another dead name | |
383 | with the same name in the child. */ | |
384 | allocate_dead_name: | |
385 | err = __mach_port_allocate_name (newtask, | |
386 | MACH_PORT_RIGHT_DEAD_NAME, | |
387 | portnames[i]); | |
388 | else | |
389 | /* Insert the chosen send right into the child. */ | |
390 | err = __mach_port_insert_right (newtask, | |
391 | portnames[i], | |
a1c93156 | 392 | insert, insert_type); |
11872325 | 393 | switch (err) |
28f540f4 | 394 | { |
11872325 RM |
395 | case KERN_NAME_EXISTS: |
396 | { | |
397 | /* It already has a send right under this name (?!). | |
398 | Well, it starts out with a send right for its task | |
399 | port, and inherits the bootstrap and exception ports | |
400 | from us. */ | |
401 | mach_port_t childport; | |
402 | mach_msg_type_name_t poly; | |
403 | assert (__mach_port_extract_right (newtask, portnames[i], | |
404 | MACH_MSG_TYPE_COPY_SEND, | |
405 | &childport, | |
406 | &poly) == 0 && | |
407 | childport == insert && | |
408 | __mach_port_deallocate (__mach_task_self (), | |
409 | childport) == 0); | |
410 | break; | |
411 | } | |
412 | ||
413 | case KERN_INVALID_CAPABILITY: | |
414 | /* The port just died. It was a send right, | |
415 | and now it's a dead name. */ | |
416 | goto allocate_dead_name; | |
417 | ||
418 | default: | |
419 | LOSE; | |
420 | break; | |
421 | ||
422 | case KERN_SUCCESS: | |
423 | /* Give the child as many user references as we have. */ | |
424 | if (refs > 1 && | |
425 | (err = __mach_port_mod_refs (newtask, | |
426 | portnames[i], | |
427 | MACH_PORT_RIGHT_SEND, | |
428 | refs - 1))) | |
429 | LOSE; | |
28f540f4 | 430 | } |
28f540f4 RM |
431 | } |
432 | } | |
433 | ||
434 | /* Unlock the standard port cells. The child must unlock its own | |
435 | copies too. */ | |
436 | for (i = 0; i < _hurd_nports; ++i) | |
437 | __spin_unlock (&_hurd_ports[i].lock); | |
438 | ports_locked = 0; | |
439 | ||
3fe9de0d | 440 | /* All state has now been copied from the parent. It is safe to |
478b92f0 | 441 | resume other parent threads. */ |
3fe9de0d RM |
442 | resume_threads (); |
443 | ||
28f540f4 RM |
444 | /* Create the child main user thread and signal thread. */ |
445 | if ((err = __thread_create (newtask, &thread)) || | |
446 | (err = __thread_create (newtask, &sigthread))) | |
11872325 | 447 | LOSE; |
28f540f4 RM |
448 | |
449 | /* Insert send rights for those threads. We previously allocated | |
478b92f0 UD |
450 | dead name rights with the names we want to give the thread ports |
451 | in the child as placeholders. Now deallocate them so we can use | |
452 | the names. */ | |
3fe9de0d RM |
453 | if ((err = __mach_port_deallocate (newtask, ss->thread)) || |
454 | (err = __mach_port_insert_right (newtask, ss->thread, | |
28f540f4 | 455 | thread, MACH_MSG_TYPE_COPY_SEND))) |
11872325 | 456 | LOSE; |
28f540f4 RM |
457 | /* We have one extra user reference created at the beginning of this |
458 | function, accounted for by mach_port_names (and which will thus be | |
459 | accounted for in the child below). This extra right gets consumed | |
460 | in the child by the store into _hurd_sigthread in the child fork. */ | |
461 | if (thread_refs > 1 && | |
3fe9de0d | 462 | (err = __mach_port_mod_refs (newtask, ss->thread, |
28f540f4 | 463 | MACH_PORT_RIGHT_SEND, |
3fe9de0d | 464 | thread_refs))) |
11872325 | 465 | LOSE; |
28f540f4 RM |
466 | if ((_hurd_msgport_thread != MACH_PORT_NULL) /* Let user have none. */ |
467 | && ((err = __mach_port_deallocate (newtask, _hurd_msgport_thread)) || | |
468 | (err = __mach_port_insert_right (newtask, _hurd_msgport_thread, | |
469 | sigthread, | |
470 | MACH_MSG_TYPE_COPY_SEND)))) | |
11872325 | 471 | LOSE; |
28f540f4 RM |
472 | if (sigthread_refs > 1 && |
473 | (err = __mach_port_mod_refs (newtask, _hurd_msgport_thread, | |
474 | MACH_PORT_RIGHT_SEND, | |
475 | sigthread_refs - 1))) | |
11872325 | 476 | LOSE; |
28f540f4 RM |
477 | |
478 | /* This seems like a convenient juncture to copy the proc server's | |
479 | idea of what addresses our argv and envp are found at from the | |
480 | parent into the child. Since we happen to know that the child | |
481 | shares our memory image, it is we who should do this copying. */ | |
482 | { | |
483 | vm_address_t argv, envp; | |
484 | err = (__USEPORT (PROC, __proc_get_arg_locations (port, &argv, &envp)) | |
485 | ?: __proc_set_arg_locations (newproc, argv, envp)); | |
486 | if (err) | |
11872325 | 487 | LOSE; |
28f540f4 | 488 | } |
e3fa2641 | 489 | |
28f540f4 RM |
490 | /* Set the child signal thread up to run the msgport server function |
491 | using the same signal thread stack copied from our address space. | |
492 | We fetch the state before longjmp'ing it so that miscellaneous | |
493 | registers not affected by longjmp (such as i386 segment registers) | |
494 | are in their normal default state. */ | |
495 | statecount = MACHINE_THREAD_STATE_COUNT; | |
496 | if (err = __thread_get_state (_hurd_msgport_thread, | |
497 | MACHINE_THREAD_STATE_FLAVOR, | |
498 | (natural_t *) &state, &statecount)) | |
11872325 | 499 | LOSE; |
28f540f4 | 500 | #if STACK_GROWTH_UP |
72e1a750 RM |
501 | #define THREADVAR_SPACE (__hurd_threadvar_max \ |
502 | * sizeof *__hurd_sightread_variables) | |
503 | if (__hurd_sigthread_stack_base == 0) | |
504 | { | |
505 | state.SP &= __hurd_threadvar_stack_mask; | |
506 | state.SP += __hurd_threadvar_stack_offset + THREADVAR_SPACE; | |
507 | } | |
508 | else | |
509 | state.SP = __hurd_sigthread_stack_base; | |
28f540f4 | 510 | #else |
72e1a750 RM |
511 | if (__hurd_sigthread_stack_end == 0) |
512 | { | |
513 | /* The signal thread has a normal stack assigned by cthreads. | |
514 | The threadvar_stack variables conveniently tell us how | |
515 | to get to the highest address in the stack, just below | |
516 | the per-thread variables. */ | |
517 | state.SP &= __hurd_threadvar_stack_mask; | |
518 | state.SP += __hurd_threadvar_stack_offset; | |
519 | } | |
520 | else | |
521 | state.SP = __hurd_sigthread_stack_end; | |
e3fa2641 | 522 | #endif |
28f540f4 RM |
523 | MACHINE_THREAD_STATE_SET_PC (&state, |
524 | (unsigned long int) _hurd_msgport_receive); | |
525 | if (err = __thread_set_state (sigthread, MACHINE_THREAD_STATE_FLAVOR, | |
526 | (natural_t *) &state, statecount)) | |
11872325 | 527 | LOSE; |
28f540f4 RM |
528 | /* We do not thread_resume SIGTHREAD here because the child |
529 | fork needs to do more setup before it can take signals. */ | |
530 | ||
531 | /* Set the child user thread up to return 1 from the setjmp above. */ | |
532 | _hurd_longjmp_thread_state (&state, env, 1); | |
3ba7b383 | 533 | |
3ba7b383 RM |
534 | /* Do special thread setup for TLS if needed. */ |
535 | if (err = _hurd_tls_fork (thread, &state)) | |
536 | LOSE; | |
3ba7b383 | 537 | |
28f540f4 RM |
538 | if (err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR, |
539 | (natural_t *) &state, statecount)) | |
11872325 | 540 | LOSE; |
28f540f4 RM |
541 | |
542 | /* Get the PID of the child from the proc server. We must do this | |
543 | before calling proc_child below, because at that point any | |
544 | authorized POSIX.1 process may kill the child task with SIGKILL. */ | |
545 | if (err = __USEPORT (PROC, __proc_task2pid (port, newtask, &pid))) | |
11872325 | 546 | LOSE; |
28f540f4 RM |
547 | |
548 | /* Register the child with the proc server. It is important that | |
549 | this be that last thing we do before starting the child thread | |
550 | running. Once proc_child has been done for the task, it appears | |
551 | as a POSIX.1 process. Any errors we get must be detected before | |
552 | this point, and the child must have a message port so it responds | |
553 | to POSIX.1 signals. */ | |
554 | if (err = __USEPORT (PROC, __proc_child (port, newtask))) | |
11872325 | 555 | LOSE; |
28f540f4 RM |
556 | |
557 | /* This must be the absolutely last thing we do; we can't assume that | |
558 | the child will remain alive for even a moment once we do this. We | |
559 | ignore errors because we have committed to the fork and are not | |
560 | allowed to return them after the process becomes visible to | |
561 | POSIX.1 (which happened right above when we called proc_child). */ | |
562 | (void) __thread_resume (thread); | |
563 | ||
564 | lose: | |
565 | if (ports_locked) | |
566 | for (i = 0; i < _hurd_nports; ++i) | |
567 | __spin_unlock (&_hurd_ports[i].lock); | |
568 | ||
3fe9de0d RM |
569 | resume_threads (); |
570 | ||
28f540f4 RM |
571 | if (newtask != MACH_PORT_NULL) |
572 | { | |
573 | if (err) | |
574 | __task_terminate (newtask); | |
575 | __mach_port_deallocate (__mach_task_self (), newtask); | |
576 | } | |
577 | if (thread != MACH_PORT_NULL) | |
578 | __mach_port_deallocate (__mach_task_self (), thread); | |
579 | if (sigthread != MACH_PORT_NULL) | |
580 | __mach_port_deallocate (__mach_task_self (), sigthread); | |
581 | if (newproc != MACH_PORT_NULL) | |
582 | __mach_port_deallocate (__mach_task_self (), newproc); | |
28f540f4 RM |
583 | |
584 | if (portnames) | |
585 | __vm_deallocate (__mach_task_self (), | |
586 | (vm_address_t) portnames, | |
587 | nportnames * sizeof (*portnames)); | |
588 | if (porttypes) | |
589 | __vm_deallocate (__mach_task_self (), | |
590 | (vm_address_t) porttypes, | |
591 | nporttypes * sizeof (*porttypes)); | |
592 | if (threads) | |
593 | { | |
594 | for (i = 0; i < nthreads; ++i) | |
595 | __mach_port_deallocate (__mach_task_self (), threads[i]); | |
596 | __vm_deallocate (__mach_task_self (), | |
597 | (vm_address_t) threads, | |
598 | nthreads * sizeof (*threads)); | |
599 | } | |
600 | ||
601 | /* Run things that want to run in the parent to restore it to | |
602 | normality. Usually prepare hooks and parent hooks are | |
603 | symmetrical: the prepare hook arrests state in some way for the | |
604 | fork, and the parent hook restores the state for the parent to | |
605 | continue executing normally. */ | |
606 | RUN_HOOK (_hurd_fork_parent_hook, ()); | |
607 | } | |
608 | else | |
609 | { | |
610 | struct hurd_sigstate *oldstates; | |
611 | ||
612 | /* We are the child task. Unlock the standard port cells, which were | |
478b92f0 UD |
613 | locked in the parent when we copied its memory. The parent has |
614 | inserted send rights with the names that were in the cells then. */ | |
28f540f4 RM |
615 | for (i = 0; i < _hurd_nports; ++i) |
616 | __spin_unlock (&_hurd_ports[i].lock); | |
617 | ||
4ac9bb2e RM |
618 | /* We are one of the (exactly) two threads in this new task, we |
619 | will take the task-global signals. */ | |
3fe9de0d | 620 | _hurd_sigthread = ss->thread; |
28f540f4 | 621 | |
4ac9bb2e RM |
622 | /* Claim our sigstate structure and unchain the rest: the |
623 | threads existed in the parent task but don't exist in this | |
624 | task (the child process). Delay freeing them until later | |
625 | because some of the further setup and unlocking might be | |
626 | required for free to work. Before we finish cleaning up, | |
627 | we will reclaim the signal thread's sigstate structure (if | |
628 | it had one). */ | |
28f540f4 RM |
629 | oldstates = _hurd_sigstates; |
630 | if (oldstates == ss) | |
631 | oldstates = ss->next; | |
632 | else | |
633 | { | |
634 | while (_hurd_sigstates->next != ss) | |
635 | _hurd_sigstates = _hurd_sigstates->next; | |
636 | _hurd_sigstates->next = ss->next; | |
637 | } | |
638 | ss->next = NULL; | |
639 | _hurd_sigstates = ss; | |
11872325 | 640 | __mutex_unlock (&_hurd_siglock); |
28f540f4 RM |
641 | |
642 | /* Fetch our new process IDs from the proc server. No need to | |
643 | refetch our pgrp; it is always inherited from the parent (so | |
644 | _hurd_pgrp is already correct), and the proc server will send us a | |
645 | proc_newids notification when it changes. */ | |
646 | err = __USEPORT (PROC, __proc_getpids (port, &_hurd_pid, &_hurd_ppid, | |
647 | &_hurd_orphaned)); | |
648 | ||
b07c5668 | 649 | /* Forking clears the trace flag. */ |
8f0c527e | 650 | __sigemptyset (&_hurdsig_traced); |
b07c5668 | 651 | |
28f540f4 RM |
652 | /* Run things that want to run in the child task to set up. */ |
653 | RUN_HOOK (_hurd_fork_child_hook, ()); | |
654 | ||
655 | /* Set up proc server-assisted fault recovery for the signal thread. */ | |
656 | _hurdsig_fault_init (); | |
657 | ||
658 | /* Start the signal thread listening on the message port. */ | |
659 | if (!err) | |
660 | err = __thread_resume (_hurd_msgport_thread); | |
661 | ||
4ac9bb2e RM |
662 | /* Reclaim the signal thread's sigstate structure and free the |
663 | other old sigstate structures. */ | |
28f540f4 RM |
664 | while (oldstates != NULL) |
665 | { | |
666 | struct hurd_sigstate *next = oldstates->next; | |
4ac9bb2e RM |
667 | |
668 | if (oldstates->thread == _hurd_msgport_thread) | |
669 | { | |
670 | /* If we have a second signal state structure then we | |
671 | must have been through here before--not good. */ | |
672 | assert (_hurd_sigstates->next == 0); | |
673 | _hurd_sigstates->next = oldstates; | |
674 | oldstates->next = 0; | |
675 | } | |
676 | else | |
677 | free (oldstates); | |
678 | ||
28f540f4 RM |
679 | oldstates = next; |
680 | } | |
4ac9bb2e | 681 | |
28f540f4 RM |
682 | /* XXX what to do if we have any errors here? */ |
683 | ||
684 | pid = 0; | |
685 | } | |
686 | ||
687 | /* Unlock things we locked before creating the child task. | |
688 | They are locked in both the parent and child tasks. */ | |
3fe9de0d RM |
689 | { |
690 | void *const *p; | |
691 | for (p = symbol_set_first_element (_hurd_fork_locks); | |
692 | ! symbol_set_end_p (_hurd_fork_locks, p); | |
693 | ++p) | |
694 | __mutex_unlock (*p); | |
695 | } | |
28f540f4 | 696 | |
11872325 | 697 | _hurd_critical_section_unlock (ss); |
28f540f4 RM |
698 | |
699 | return err ? __hurd_fail (err) : pid; | |
700 | } | |
d1436edc | 701 | libc_hidden_def (__fork) |
28f540f4 RM |
702 | |
703 | weak_alias (__fork, fork) |