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b168057a | 1 | /* Copyright (C) 1994-2015 Free Software Foundation, Inc. |
478b92f0 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
478b92f0 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
28f540f4 | 8 | |
478b92f0 UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 RM |
17 | |
18 | #include <errno.h> | |
19 | #include <unistd.h> | |
20 | #include <hurd.h> | |
21 | #include <hurd/signal.h> | |
22 | #include <setjmp.h> | |
8f480b4b | 23 | #include <thread_state.h> |
28f540f4 RM |
24 | #include <sysdep.h> /* For stack growth direction. */ |
25 | #include "set-hooks.h" | |
26 | #include <assert.h> | |
27 | #include "hurdmalloc.h" /* XXX */ | |
3ba7b383 | 28 | #include <tls.h> |
28f540f4 | 29 | |
6b87a564 UD |
30 | #undef __fork |
31 | ||
28f540f4 RM |
32 | |
33 | /* Things that want to be locked while forking. */ | |
3fe9de0d | 34 | symbol_set_declare (_hurd_fork_locks) |
28f540f4 RM |
35 | |
36 | ||
7b7bab13 ST |
37 | /* Application callbacks registered through pthread_atfork. */ |
38 | DEFINE_HOOK (_hurd_atfork_prepare_hook, (void)); | |
39 | DEFINE_HOOK (_hurd_atfork_child_hook, (void)); | |
40 | DEFINE_HOOK (_hurd_atfork_parent_hook, (void)); | |
41 | ||
28f540f4 RM |
42 | /* Things that want to be called before we fork, to prepare the parent for |
43 | task_create, when the new child task will inherit our address space. */ | |
44 | DEFINE_HOOK (_hurd_fork_prepare_hook, (void)); | |
45 | ||
46 | /* Things that want to be called when we are forking, with the above all | |
47 | locked. They are passed the task port of the child. The child process | |
48 | is all set up except for doing proc_child, and has no threads yet. */ | |
49 | DEFINE_HOOK (_hurd_fork_setup_hook, (void)); | |
50 | ||
51 | /* Things to be run in the child fork. */ | |
52 | DEFINE_HOOK (_hurd_fork_child_hook, (void)); | |
53 | ||
54 | /* Things to be run in the parent fork. */ | |
55 | DEFINE_HOOK (_hurd_fork_parent_hook, (void)); | |
56 | ||
57 | ||
58 | /* Clone the calling process, creating an exact copy. | |
59 | Return -1 for errors, 0 to the new process, | |
60 | and the process ID of the new process to the old process. */ | |
61 | pid_t | |
62 | __fork (void) | |
63 | { | |
64 | jmp_buf env; | |
65 | pid_t pid; | |
66 | size_t i; | |
67 | error_t err; | |
28f540f4 | 68 | struct hurd_sigstate *volatile ss; |
28f540f4 | 69 | |
7b7bab13 ST |
70 | RUN_HOOK (_hurd_atfork_prepare_hook, ()); |
71 | ||
28f540f4 | 72 | ss = _hurd_self_sigstate (); |
8f0c527e | 73 | __spin_lock (&ss->critical_section_lock); |
11872325 RM |
74 | |
75 | #undef LOSE | |
221dc560 | 76 | #define LOSE do { assert_perror (err); goto lose; } while (0) /* XXX */ |
28f540f4 RM |
77 | |
78 | if (! setjmp (env)) | |
79 | { | |
80 | process_t newproc; | |
81 | task_t newtask; | |
82 | thread_t thread, sigthread; | |
83 | mach_port_urefs_t thread_refs, sigthread_refs; | |
84 | struct machine_thread_state state; | |
85 | mach_msg_type_number_t statecount; | |
86 | mach_port_t *portnames = NULL; | |
87 | mach_msg_type_number_t nportnames = 0; | |
88 | mach_port_type_t *porttypes = NULL; | |
89 | mach_msg_type_number_t nporttypes = 0; | |
90 | thread_t *threads = NULL; | |
91 | mach_msg_type_number_t nthreads = 0; | |
3fe9de0d RM |
92 | int ports_locked = 0, stopped = 0; |
93 | ||
94 | void resume_threads (void) | |
95 | { | |
96 | if (! stopped) | |
97 | return; | |
98 | ||
99 | assert (threads); | |
100 | ||
101 | for (i = 0; i < nthreads; ++i) | |
102 | if (threads[i] != ss->thread) | |
103 | __thread_resume (threads[i]); | |
104 | stopped = 0; | |
105 | } | |
28f540f4 RM |
106 | |
107 | /* Run things that prepare for forking before we create the task. */ | |
108 | RUN_HOOK (_hurd_fork_prepare_hook, ()); | |
109 | ||
110 | /* Lock things that want to be locked before we fork. */ | |
3fe9de0d RM |
111 | { |
112 | void *const *p; | |
113 | for (p = symbol_set_first_element (_hurd_fork_locks); | |
114 | ! symbol_set_end_p (_hurd_fork_locks, p); | |
115 | ++p) | |
116 | __mutex_lock (*p); | |
117 | } | |
11872325 | 118 | __mutex_lock (&_hurd_siglock); |
e3fa2641 | 119 | |
28f540f4 RM |
120 | newtask = MACH_PORT_NULL; |
121 | thread = sigthread = MACH_PORT_NULL; | |
122 | newproc = MACH_PORT_NULL; | |
123 | ||
124 | /* Lock all the port cells for the standard ports while we copy the | |
125 | address space. We want to insert all the send rights into the | |
126 | child with the same names. */ | |
127 | for (i = 0; i < _hurd_nports; ++i) | |
128 | __spin_lock (&_hurd_ports[i].lock); | |
129 | ports_locked = 1; | |
130 | ||
e3fa2641 | 131 | |
17a62de1 ST |
132 | /* Keep our SS locked while stopping other threads, so they don't get a |
133 | chance to have it locked in the copied space. */ | |
134 | __spin_lock (&ss->lock); | |
3fe9de0d RM |
135 | /* Stop all other threads while copying the address space, |
136 | so nothing changes. */ | |
137 | err = __proc_dostop (_hurd_ports[INIT_PORT_PROC].port, ss->thread); | |
17a62de1 | 138 | __spin_unlock (&ss->lock); |
3fe9de0d | 139 | if (!err) |
478b92f0 UD |
140 | { |
141 | stopped = 1; | |
3fe9de0d | 142 | |
6df1b247 RM |
143 | #define XXX_KERNEL_PAGE_FAULT_BUG /* XXX work around page fault bug in mk */ |
144 | ||
145 | #ifdef XXX_KERNEL_PAGE_FAULT_BUG | |
146 | /* Gag me with a pitchfork. | |
147 | The bug scenario is this: | |
148 | ||
149 | - The page containing __mach_task_self_ is paged out. | |
150 | - The signal thread was faulting on that page when we | |
151 | suspended it via proc_dostop. It holds some lock, or set | |
152 | some busy bit, or somesuch. | |
153 | - Now this thread faults on that same page. | |
154 | - GRATUIOUS DEADLOCK | |
155 | ||
156 | We can break the deadlock by aborting the thread that faulted | |
157 | first, which if the bug happened was the signal thread because | |
158 | it is the only other thread and we just suspended it. | |
159 | */ | |
160 | __thread_abort (_hurd_msgport_thread); | |
161 | #endif | |
3fe9de0d | 162 | /* Create the child task. It will inherit a copy of our memory. */ |
7595ddb8 RM |
163 | err = __task_create (__mach_task_self (), |
164 | #ifdef KERN_INVALID_LEDGER | |
165 | NULL, 0, /* OSF Mach */ | |
166 | #endif | |
167 | 1, &newtask); | |
478b92f0 | 168 | } |
11872325 RM |
169 | |
170 | /* Unlock the global signal state lock, so we do not | |
171 | block the signal thread any longer than necessary. */ | |
172 | __mutex_unlock (&_hurd_siglock); | |
173 | ||
174 | if (err) | |
175 | LOSE; | |
28f540f4 RM |
176 | |
177 | /* Fetch the names of all ports used in this task. */ | |
178 | if (err = __mach_port_names (__mach_task_self (), | |
179 | &portnames, &nportnames, | |
180 | &porttypes, &nporttypes)) | |
11872325 | 181 | LOSE; |
28f540f4 RM |
182 | if (nportnames != nporttypes) |
183 | { | |
184 | err = EGRATUITOUS; | |
11872325 | 185 | LOSE; |
28f540f4 RM |
186 | } |
187 | ||
188 | /* Get send rights for all the threads in this task. | |
189 | We want to avoid giving these rights to the child. */ | |
190 | if (err = __task_threads (__mach_task_self (), &threads, &nthreads)) | |
11872325 | 191 | LOSE; |
28f540f4 RM |
192 | |
193 | /* Get the child process's proc server port. We will insert it into | |
194 | the child with the same name as we use for our own proc server | |
195 | port; and we will need it to set the child's message port. */ | |
196 | if (err = __proc_task2proc (_hurd_ports[INIT_PORT_PROC].port, | |
197 | newtask, &newproc)) | |
11872325 | 198 | LOSE; |
28f540f4 RM |
199 | |
200 | /* Insert all our port rights into the child task. */ | |
201 | thread_refs = sigthread_refs = 0; | |
202 | for (i = 0; i < nportnames; ++i) | |
203 | { | |
204 | if (porttypes[i] & MACH_PORT_TYPE_RECEIVE) | |
205 | { | |
206 | /* This is a receive right. We want to give the child task | |
207 | its own new receive right under the same name. */ | |
208 | err = __mach_port_allocate_name (newtask, | |
209 | MACH_PORT_RIGHT_RECEIVE, | |
210 | portnames[i]); | |
211 | if (err == KERN_NAME_EXISTS) | |
212 | { | |
213 | /* It already has a right under this name (?!). Well, | |
214 | there is this bizarre old Mach IPC feature (in #ifdef | |
215 | MACH_IPC_COMPAT in the ukernel) which results in new | |
216 | tasks getting a new receive right for task special | |
217 | port number 2. What else might be going on I'm not | |
218 | sure. So let's check. */ | |
219 | #if !MACH_IPC_COMPAT | |
220 | #define TASK_NOTIFY_PORT 2 | |
221 | #endif | |
222 | assert (({ mach_port_t thisport, notify_port; | |
223 | mach_msg_type_name_t poly; | |
224 | (__task_get_special_port (newtask, | |
225 | TASK_NOTIFY_PORT, | |
226 | ¬ify_port) == 0 && | |
e3fa2641 | 227 | __mach_port_extract_right |
28f540f4 RM |
228 | (newtask, |
229 | portnames[i], | |
230 | MACH_MSG_TYPE_MAKE_SEND, | |
231 | &thisport, &poly) == 0 && | |
232 | (thisport == notify_port) && | |
233 | __mach_port_deallocate (__mach_task_self (), | |
234 | thisport) == 0 && | |
235 | __mach_port_deallocate (__mach_task_self (), | |
236 | notify_port) == 0); | |
237 | })); | |
238 | } | |
239 | else if (err) | |
11872325 | 240 | LOSE; |
28f540f4 RM |
241 | if (porttypes[i] & MACH_PORT_TYPE_SEND) |
242 | { | |
243 | /* Give the child as many send rights for its receive | |
244 | right as we have for ours. */ | |
245 | mach_port_urefs_t refs; | |
246 | mach_port_t port; | |
247 | mach_msg_type_name_t poly; | |
248 | if (err = __mach_port_get_refs (__mach_task_self (), | |
249 | portnames[i], | |
250 | MACH_PORT_RIGHT_SEND, | |
251 | &refs)) | |
11872325 | 252 | LOSE; |
28f540f4 RM |
253 | if (err = __mach_port_extract_right (newtask, |
254 | portnames[i], | |
255 | MACH_MSG_TYPE_MAKE_SEND, | |
256 | &port, &poly)) | |
11872325 | 257 | LOSE; |
28f540f4 RM |
258 | if (portnames[i] == _hurd_msgport) |
259 | { | |
260 | /* We just created a receive right for the child's | |
261 | message port and are about to insert send rights | |
262 | for it. Now, while we happen to have a send right | |
263 | for it, give it to the proc server. */ | |
264 | mach_port_t old; | |
265 | if (err = __proc_setmsgport (newproc, port, &old)) | |
11872325 | 266 | LOSE; |
28f540f4 RM |
267 | if (old != MACH_PORT_NULL) |
268 | /* XXX what to do here? */ | |
269 | __mach_port_deallocate (__mach_task_self (), old); | |
4ca84cff RM |
270 | /* The new task will receive its own exceptions |
271 | on its message port. */ | |
7595ddb8 RM |
272 | if (err = |
273 | #ifdef TASK_EXCEPTION_PORT | |
274 | __task_set_special_port (newtask, | |
275 | TASK_EXCEPTION_PORT, | |
276 | port) | |
277 | #elif defined (EXC_MASK_ALL) | |
278 | __task_set_exception_ports | |
279 | (newtask, EXC_MASK_ALL & ~(EXC_MASK_SYSCALL | |
280 | | EXC_MASK_MACH_SYSCALL | |
281 | | EXC_MASK_RPC_ALERT), | |
282 | port, EXCEPTION_DEFAULT, MACHINE_THREAD_STATE) | |
283 | #else | |
284 | # error task_set_exception_port? | |
285 | #endif | |
286 | ) | |
4ca84cff | 287 | LOSE; |
28f540f4 RM |
288 | } |
289 | if (err = __mach_port_insert_right (newtask, | |
290 | portnames[i], | |
291 | port, | |
292 | MACH_MSG_TYPE_MOVE_SEND)) | |
11872325 | 293 | LOSE; |
28f540f4 RM |
294 | if (refs > 1 && |
295 | (err = __mach_port_mod_refs (newtask, | |
296 | portnames[i], | |
297 | MACH_PORT_RIGHT_SEND, | |
298 | refs - 1))) | |
11872325 | 299 | LOSE; |
28f540f4 RM |
300 | } |
301 | if (porttypes[i] & MACH_PORT_TYPE_SEND_ONCE) | |
302 | { | |
303 | /* Give the child a send-once right for its receive right, | |
304 | since we have one for ours. */ | |
305 | mach_port_t port; | |
306 | mach_msg_type_name_t poly; | |
307 | if (err = __mach_port_extract_right | |
308 | (newtask, | |
309 | portnames[i], | |
310 | MACH_MSG_TYPE_MAKE_SEND_ONCE, | |
311 | &port, &poly)) | |
11872325 | 312 | LOSE; |
28f540f4 RM |
313 | if (err = __mach_port_insert_right |
314 | (newtask, | |
315 | portnames[i], port, | |
316 | MACH_MSG_TYPE_MOVE_SEND_ONCE)) | |
11872325 | 317 | LOSE; |
28f540f4 RM |
318 | } |
319 | } | |
11872325 RM |
320 | else if (porttypes[i] & |
321 | (MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_DEAD_NAME)) | |
28f540f4 RM |
322 | { |
323 | /* This is a send right or a dead name. | |
324 | Give the child as many references for it as we have. */ | |
7f513ec8 | 325 | mach_port_urefs_t refs = 0, *record_refs = NULL; |
28f540f4 | 326 | mach_port_t insert; |
3125073e | 327 | mach_msg_type_name_t insert_type = MACH_MSG_TYPE_COPY_SEND; |
7119ea6d RM |
328 | if (portnames[i] == newtask || portnames[i] == newproc) |
329 | /* Skip the name we use for the child's task or proc ports. */ | |
28f540f4 RM |
330 | continue; |
331 | if (portnames[i] == __mach_task_self ()) | |
332 | /* For the name we use for our own task port, | |
333 | insert the child's task port instead. */ | |
334 | insert = newtask; | |
335 | else if (portnames[i] == _hurd_ports[INIT_PORT_PROC].port) | |
336 | { | |
7119ea6d RM |
337 | /* Use the proc server port for the new task. */ |
338 | insert = newproc; | |
339 | insert_type = MACH_MSG_TYPE_COPY_SEND; | |
28f540f4 | 340 | } |
3fe9de0d | 341 | else if (portnames[i] == ss->thread) |
28f540f4 RM |
342 | { |
343 | /* For the name we use for our own thread port, we will | |
344 | insert the thread port for the child main user thread | |
345 | after we create it. */ | |
346 | insert = MACH_PORT_NULL; | |
347 | record_refs = &thread_refs; | |
348 | /* Allocate a dead name right for this name as a | |
478b92f0 UD |
349 | placeholder, so the kernel will not chose this name |
350 | for any other new port (it might use it for one of the | |
351 | rights created when a thread is created). */ | |
28f540f4 RM |
352 | if (err = __mach_port_allocate_name |
353 | (newtask, MACH_PORT_RIGHT_DEAD_NAME, portnames[i])) | |
11872325 | 354 | LOSE; |
28f540f4 RM |
355 | } |
356 | else if (portnames[i] == _hurd_msgport_thread) | |
357 | /* For the name we use for our signal thread's thread port, | |
358 | we will insert the thread port for the child's signal | |
359 | thread after we create it. */ | |
360 | { | |
361 | insert = MACH_PORT_NULL; | |
362 | record_refs = &sigthread_refs; | |
363 | /* Allocate a dead name right as a placeholder. */ | |
364 | if (err = __mach_port_allocate_name | |
365 | (newtask, MACH_PORT_RIGHT_DEAD_NAME, portnames[i])) | |
11872325 | 366 | LOSE; |
28f540f4 RM |
367 | } |
368 | else | |
369 | { | |
370 | /* Skip the name we use for any of our own thread ports. */ | |
371 | mach_msg_type_number_t j; | |
372 | for (j = 0; j < nthreads; ++j) | |
373 | if (portnames[i] == threads[j]) | |
374 | break; | |
375 | if (j < nthreads) | |
376 | continue; | |
377 | ||
3125073e | 378 | /* Copy our own send right. */ |
28f540f4 RM |
379 | insert = portnames[i]; |
380 | } | |
381 | /* Find out how many user references we have for | |
382 | the send right with this name. */ | |
383 | if (err = __mach_port_get_refs (__mach_task_self (), | |
384 | portnames[i], | |
385 | MACH_PORT_RIGHT_SEND, | |
386 | record_refs ?: &refs)) | |
11872325 | 387 | LOSE; |
28f540f4 RM |
388 | if (insert == MACH_PORT_NULL) |
389 | continue; | |
11872325 RM |
390 | if (insert == portnames[i] && |
391 | (porttypes[i] & MACH_PORT_TYPE_DEAD_NAME)) | |
392 | /* This is a dead name; allocate another dead name | |
393 | with the same name in the child. */ | |
394 | allocate_dead_name: | |
395 | err = __mach_port_allocate_name (newtask, | |
396 | MACH_PORT_RIGHT_DEAD_NAME, | |
397 | portnames[i]); | |
398 | else | |
399 | /* Insert the chosen send right into the child. */ | |
400 | err = __mach_port_insert_right (newtask, | |
401 | portnames[i], | |
a1c93156 | 402 | insert, insert_type); |
11872325 | 403 | switch (err) |
28f540f4 | 404 | { |
11872325 RM |
405 | case KERN_NAME_EXISTS: |
406 | { | |
407 | /* It already has a send right under this name (?!). | |
408 | Well, it starts out with a send right for its task | |
409 | port, and inherits the bootstrap and exception ports | |
410 | from us. */ | |
411 | mach_port_t childport; | |
412 | mach_msg_type_name_t poly; | |
413 | assert (__mach_port_extract_right (newtask, portnames[i], | |
414 | MACH_MSG_TYPE_COPY_SEND, | |
415 | &childport, | |
416 | &poly) == 0 && | |
417 | childport == insert && | |
418 | __mach_port_deallocate (__mach_task_self (), | |
419 | childport) == 0); | |
420 | break; | |
421 | } | |
422 | ||
423 | case KERN_INVALID_CAPABILITY: | |
424 | /* The port just died. It was a send right, | |
425 | and now it's a dead name. */ | |
426 | goto allocate_dead_name; | |
427 | ||
428 | default: | |
429 | LOSE; | |
430 | break; | |
431 | ||
432 | case KERN_SUCCESS: | |
433 | /* Give the child as many user references as we have. */ | |
434 | if (refs > 1 && | |
435 | (err = __mach_port_mod_refs (newtask, | |
436 | portnames[i], | |
437 | MACH_PORT_RIGHT_SEND, | |
438 | refs - 1))) | |
439 | LOSE; | |
28f540f4 | 440 | } |
28f540f4 RM |
441 | } |
442 | } | |
443 | ||
444 | /* Unlock the standard port cells. The child must unlock its own | |
445 | copies too. */ | |
446 | for (i = 0; i < _hurd_nports; ++i) | |
447 | __spin_unlock (&_hurd_ports[i].lock); | |
448 | ports_locked = 0; | |
449 | ||
3fe9de0d | 450 | /* All state has now been copied from the parent. It is safe to |
478b92f0 | 451 | resume other parent threads. */ |
3fe9de0d RM |
452 | resume_threads (); |
453 | ||
28f540f4 RM |
454 | /* Create the child main user thread and signal thread. */ |
455 | if ((err = __thread_create (newtask, &thread)) || | |
456 | (err = __thread_create (newtask, &sigthread))) | |
11872325 | 457 | LOSE; |
28f540f4 RM |
458 | |
459 | /* Insert send rights for those threads. We previously allocated | |
478b92f0 UD |
460 | dead name rights with the names we want to give the thread ports |
461 | in the child as placeholders. Now deallocate them so we can use | |
462 | the names. */ | |
3fe9de0d RM |
463 | if ((err = __mach_port_deallocate (newtask, ss->thread)) || |
464 | (err = __mach_port_insert_right (newtask, ss->thread, | |
28f540f4 | 465 | thread, MACH_MSG_TYPE_COPY_SEND))) |
11872325 | 466 | LOSE; |
28f540f4 RM |
467 | /* We have one extra user reference created at the beginning of this |
468 | function, accounted for by mach_port_names (and which will thus be | |
469 | accounted for in the child below). This extra right gets consumed | |
470 | in the child by the store into _hurd_sigthread in the child fork. */ | |
471 | if (thread_refs > 1 && | |
3fe9de0d | 472 | (err = __mach_port_mod_refs (newtask, ss->thread, |
28f540f4 | 473 | MACH_PORT_RIGHT_SEND, |
3fe9de0d | 474 | thread_refs))) |
11872325 | 475 | LOSE; |
28f540f4 RM |
476 | if ((_hurd_msgport_thread != MACH_PORT_NULL) /* Let user have none. */ |
477 | && ((err = __mach_port_deallocate (newtask, _hurd_msgport_thread)) || | |
478 | (err = __mach_port_insert_right (newtask, _hurd_msgport_thread, | |
479 | sigthread, | |
480 | MACH_MSG_TYPE_COPY_SEND)))) | |
11872325 | 481 | LOSE; |
28f540f4 RM |
482 | if (sigthread_refs > 1 && |
483 | (err = __mach_port_mod_refs (newtask, _hurd_msgport_thread, | |
484 | MACH_PORT_RIGHT_SEND, | |
485 | sigthread_refs - 1))) | |
11872325 | 486 | LOSE; |
28f540f4 RM |
487 | |
488 | /* This seems like a convenient juncture to copy the proc server's | |
489 | idea of what addresses our argv and envp are found at from the | |
490 | parent into the child. Since we happen to know that the child | |
491 | shares our memory image, it is we who should do this copying. */ | |
492 | { | |
493 | vm_address_t argv, envp; | |
494 | err = (__USEPORT (PROC, __proc_get_arg_locations (port, &argv, &envp)) | |
495 | ?: __proc_set_arg_locations (newproc, argv, envp)); | |
496 | if (err) | |
11872325 | 497 | LOSE; |
28f540f4 | 498 | } |
e3fa2641 | 499 | |
28f540f4 RM |
500 | /* Set the child signal thread up to run the msgport server function |
501 | using the same signal thread stack copied from our address space. | |
502 | We fetch the state before longjmp'ing it so that miscellaneous | |
503 | registers not affected by longjmp (such as i386 segment registers) | |
504 | are in their normal default state. */ | |
505 | statecount = MACHINE_THREAD_STATE_COUNT; | |
506 | if (err = __thread_get_state (_hurd_msgport_thread, | |
507 | MACHINE_THREAD_STATE_FLAVOR, | |
508 | (natural_t *) &state, &statecount)) | |
11872325 | 509 | LOSE; |
28f540f4 | 510 | #if STACK_GROWTH_UP |
72e1a750 RM |
511 | #define THREADVAR_SPACE (__hurd_threadvar_max \ |
512 | * sizeof *__hurd_sightread_variables) | |
513 | if (__hurd_sigthread_stack_base == 0) | |
514 | { | |
515 | state.SP &= __hurd_threadvar_stack_mask; | |
516 | state.SP += __hurd_threadvar_stack_offset + THREADVAR_SPACE; | |
517 | } | |
518 | else | |
519 | state.SP = __hurd_sigthread_stack_base; | |
28f540f4 | 520 | #else |
72e1a750 RM |
521 | if (__hurd_sigthread_stack_end == 0) |
522 | { | |
523 | /* The signal thread has a normal stack assigned by cthreads. | |
524 | The threadvar_stack variables conveniently tell us how | |
525 | to get to the highest address in the stack, just below | |
526 | the per-thread variables. */ | |
527 | state.SP &= __hurd_threadvar_stack_mask; | |
528 | state.SP += __hurd_threadvar_stack_offset; | |
529 | } | |
530 | else | |
531 | state.SP = __hurd_sigthread_stack_end; | |
e3fa2641 | 532 | #endif |
28f540f4 RM |
533 | MACHINE_THREAD_STATE_SET_PC (&state, |
534 | (unsigned long int) _hurd_msgport_receive); | |
535 | if (err = __thread_set_state (sigthread, MACHINE_THREAD_STATE_FLAVOR, | |
536 | (natural_t *) &state, statecount)) | |
11872325 | 537 | LOSE; |
28f540f4 RM |
538 | /* We do not thread_resume SIGTHREAD here because the child |
539 | fork needs to do more setup before it can take signals. */ | |
540 | ||
541 | /* Set the child user thread up to return 1 from the setjmp above. */ | |
542 | _hurd_longjmp_thread_state (&state, env, 1); | |
3ba7b383 | 543 | |
3ba7b383 RM |
544 | /* Do special thread setup for TLS if needed. */ |
545 | if (err = _hurd_tls_fork (thread, &state)) | |
546 | LOSE; | |
3ba7b383 | 547 | |
28f540f4 RM |
548 | if (err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR, |
549 | (natural_t *) &state, statecount)) | |
11872325 | 550 | LOSE; |
28f540f4 RM |
551 | |
552 | /* Get the PID of the child from the proc server. We must do this | |
553 | before calling proc_child below, because at that point any | |
554 | authorized POSIX.1 process may kill the child task with SIGKILL. */ | |
555 | if (err = __USEPORT (PROC, __proc_task2pid (port, newtask, &pid))) | |
11872325 | 556 | LOSE; |
28f540f4 RM |
557 | |
558 | /* Register the child with the proc server. It is important that | |
559 | this be that last thing we do before starting the child thread | |
560 | running. Once proc_child has been done for the task, it appears | |
561 | as a POSIX.1 process. Any errors we get must be detected before | |
562 | this point, and the child must have a message port so it responds | |
563 | to POSIX.1 signals. */ | |
564 | if (err = __USEPORT (PROC, __proc_child (port, newtask))) | |
11872325 | 565 | LOSE; |
28f540f4 RM |
566 | |
567 | /* This must be the absolutely last thing we do; we can't assume that | |
568 | the child will remain alive for even a moment once we do this. We | |
569 | ignore errors because we have committed to the fork and are not | |
570 | allowed to return them after the process becomes visible to | |
571 | POSIX.1 (which happened right above when we called proc_child). */ | |
572 | (void) __thread_resume (thread); | |
573 | ||
574 | lose: | |
575 | if (ports_locked) | |
576 | for (i = 0; i < _hurd_nports; ++i) | |
577 | __spin_unlock (&_hurd_ports[i].lock); | |
578 | ||
3fe9de0d RM |
579 | resume_threads (); |
580 | ||
28f540f4 RM |
581 | if (newtask != MACH_PORT_NULL) |
582 | { | |
583 | if (err) | |
584 | __task_terminate (newtask); | |
585 | __mach_port_deallocate (__mach_task_self (), newtask); | |
586 | } | |
587 | if (thread != MACH_PORT_NULL) | |
588 | __mach_port_deallocate (__mach_task_self (), thread); | |
589 | if (sigthread != MACH_PORT_NULL) | |
590 | __mach_port_deallocate (__mach_task_self (), sigthread); | |
591 | if (newproc != MACH_PORT_NULL) | |
592 | __mach_port_deallocate (__mach_task_self (), newproc); | |
28f540f4 RM |
593 | |
594 | if (portnames) | |
595 | __vm_deallocate (__mach_task_self (), | |
596 | (vm_address_t) portnames, | |
597 | nportnames * sizeof (*portnames)); | |
598 | if (porttypes) | |
599 | __vm_deallocate (__mach_task_self (), | |
600 | (vm_address_t) porttypes, | |
601 | nporttypes * sizeof (*porttypes)); | |
602 | if (threads) | |
603 | { | |
604 | for (i = 0; i < nthreads; ++i) | |
605 | __mach_port_deallocate (__mach_task_self (), threads[i]); | |
606 | __vm_deallocate (__mach_task_self (), | |
607 | (vm_address_t) threads, | |
608 | nthreads * sizeof (*threads)); | |
609 | } | |
610 | ||
611 | /* Run things that want to run in the parent to restore it to | |
612 | normality. Usually prepare hooks and parent hooks are | |
613 | symmetrical: the prepare hook arrests state in some way for the | |
614 | fork, and the parent hook restores the state for the parent to | |
615 | continue executing normally. */ | |
616 | RUN_HOOK (_hurd_fork_parent_hook, ()); | |
617 | } | |
618 | else | |
619 | { | |
620 | struct hurd_sigstate *oldstates; | |
621 | ||
622 | /* We are the child task. Unlock the standard port cells, which were | |
478b92f0 UD |
623 | locked in the parent when we copied its memory. The parent has |
624 | inserted send rights with the names that were in the cells then. */ | |
28f540f4 RM |
625 | for (i = 0; i < _hurd_nports; ++i) |
626 | __spin_unlock (&_hurd_ports[i].lock); | |
627 | ||
4ac9bb2e RM |
628 | /* We are one of the (exactly) two threads in this new task, we |
629 | will take the task-global signals. */ | |
3fe9de0d | 630 | _hurd_sigthread = ss->thread; |
28f540f4 | 631 | |
4ac9bb2e RM |
632 | /* Claim our sigstate structure and unchain the rest: the |
633 | threads existed in the parent task but don't exist in this | |
634 | task (the child process). Delay freeing them until later | |
635 | because some of the further setup and unlocking might be | |
636 | required for free to work. Before we finish cleaning up, | |
637 | we will reclaim the signal thread's sigstate structure (if | |
638 | it had one). */ | |
28f540f4 RM |
639 | oldstates = _hurd_sigstates; |
640 | if (oldstates == ss) | |
641 | oldstates = ss->next; | |
642 | else | |
643 | { | |
644 | while (_hurd_sigstates->next != ss) | |
645 | _hurd_sigstates = _hurd_sigstates->next; | |
646 | _hurd_sigstates->next = ss->next; | |
647 | } | |
648 | ss->next = NULL; | |
649 | _hurd_sigstates = ss; | |
11872325 | 650 | __mutex_unlock (&_hurd_siglock); |
28f540f4 RM |
651 | |
652 | /* Fetch our new process IDs from the proc server. No need to | |
653 | refetch our pgrp; it is always inherited from the parent (so | |
654 | _hurd_pgrp is already correct), and the proc server will send us a | |
655 | proc_newids notification when it changes. */ | |
656 | err = __USEPORT (PROC, __proc_getpids (port, &_hurd_pid, &_hurd_ppid, | |
657 | &_hurd_orphaned)); | |
658 | ||
b07c5668 | 659 | /* Forking clears the trace flag. */ |
8f0c527e | 660 | __sigemptyset (&_hurdsig_traced); |
b07c5668 | 661 | |
28f540f4 RM |
662 | /* Run things that want to run in the child task to set up. */ |
663 | RUN_HOOK (_hurd_fork_child_hook, ()); | |
664 | ||
665 | /* Set up proc server-assisted fault recovery for the signal thread. */ | |
666 | _hurdsig_fault_init (); | |
667 | ||
668 | /* Start the signal thread listening on the message port. */ | |
669 | if (!err) | |
670 | err = __thread_resume (_hurd_msgport_thread); | |
671 | ||
4ac9bb2e RM |
672 | /* Reclaim the signal thread's sigstate structure and free the |
673 | other old sigstate structures. */ | |
28f540f4 RM |
674 | while (oldstates != NULL) |
675 | { | |
676 | struct hurd_sigstate *next = oldstates->next; | |
4ac9bb2e RM |
677 | |
678 | if (oldstates->thread == _hurd_msgport_thread) | |
679 | { | |
680 | /* If we have a second signal state structure then we | |
681 | must have been through here before--not good. */ | |
682 | assert (_hurd_sigstates->next == 0); | |
683 | _hurd_sigstates->next = oldstates; | |
684 | oldstates->next = 0; | |
685 | } | |
686 | else | |
687 | free (oldstates); | |
688 | ||
28f540f4 RM |
689 | oldstates = next; |
690 | } | |
4ac9bb2e | 691 | |
28f540f4 RM |
692 | /* XXX what to do if we have any errors here? */ |
693 | ||
694 | pid = 0; | |
695 | } | |
696 | ||
697 | /* Unlock things we locked before creating the child task. | |
698 | They are locked in both the parent and child tasks. */ | |
3fe9de0d RM |
699 | { |
700 | void *const *p; | |
701 | for (p = symbol_set_first_element (_hurd_fork_locks); | |
702 | ! symbol_set_end_p (_hurd_fork_locks, p); | |
703 | ++p) | |
704 | __mutex_unlock (*p); | |
705 | } | |
28f540f4 | 706 | |
11872325 | 707 | _hurd_critical_section_unlock (ss); |
28f540f4 | 708 | |
7b7bab13 ST |
709 | if (!err) |
710 | { | |
711 | if (pid != 0) | |
712 | RUN_HOOK (_hurd_atfork_parent_hook, ()); | |
713 | else | |
714 | RUN_HOOK (_hurd_atfork_child_hook, ()); | |
715 | } | |
716 | ||
28f540f4 RM |
717 | return err ? __hurd_fail (err) : pid; |
718 | } | |
d1436edc | 719 | libc_hidden_def (__fork) |
28f540f4 RM |
720 | |
721 | weak_alias (__fork, fork) |