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831b7825 TS |
1 | /* |
2 | * Emulation of Linux signals | |
3 | * | |
4 | * Copyright (c) 2003 Fabrice Bellard | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
530e7615 BS |
18 | * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
19 | * MA 02110-1301, USA. | |
831b7825 TS |
20 | */ |
21 | #include <stdlib.h> | |
22 | #include <stdio.h> | |
23 | #include <string.h> | |
24 | #include <stdarg.h> | |
25 | #include <unistd.h> | |
26 | #include <signal.h> | |
27 | #include <errno.h> | |
28 | #include <sys/ucontext.h> | |
29 | ||
30 | #ifdef __ia64__ | |
31 | #undef uc_mcontext | |
32 | #undef uc_sigmask | |
33 | #undef uc_stack | |
34 | #undef uc_link | |
35 | #endif | |
36 | ||
37 | #include <signal.h> | |
38 | ||
39 | #include "qemu.h" | |
7d99a001 | 40 | #include "qemu-common.h" |
831b7825 TS |
41 | |
42 | #define DEBUG_SIGNAL | |
43 | ||
44 | #define MAX_SIGQUEUE_SIZE 1024 | |
45 | ||
46 | struct sigqueue { | |
47 | struct sigqueue *next; | |
48 | target_siginfo_t info; | |
49 | }; | |
50 | ||
51 | struct emulated_sigaction { | |
52 | struct target_sigaction sa; | |
53 | int pending; /* true if signal is pending */ | |
54 | struct sigqueue *first; | |
55 | struct sigqueue info; /* in order to always have memory for the | |
56 | first signal, we put it here */ | |
57 | }; | |
58 | ||
249c4c32 | 59 | static struct sigaltstack target_sigaltstack_used = { |
831b7825 TS |
60 | 0, 0, SA_DISABLE |
61 | }; | |
62 | ||
63 | static struct emulated_sigaction sigact_table[NSIG]; | |
64 | static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */ | |
65 | static struct sigqueue *first_free; /* first free siginfo queue entry */ | |
66 | static int signal_pending; /* non zero if a signal may be pending */ | |
67 | ||
68 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
69 | void *puc); | |
70 | ||
71 | ||
72 | static inline int host_to_target_signal(int sig) | |
73 | { | |
74 | return sig; | |
75 | } | |
76 | ||
77 | static inline int target_to_host_signal(int sig) | |
78 | { | |
79 | return sig; | |
80 | } | |
81 | ||
82 | /* siginfo conversion */ | |
83 | ||
84 | ||
85 | ||
86 | void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) | |
87 | { | |
88 | ||
89 | } | |
90 | ||
91 | void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) | |
92 | { | |
93 | ||
94 | } | |
95 | ||
96 | void signal_init(void) | |
97 | { | |
98 | struct sigaction act; | |
99 | int i; | |
100 | ||
101 | /* set all host signal handlers. ALL signals are blocked during | |
102 | the handlers to serialize them. */ | |
103 | sigfillset(&act.sa_mask); | |
104 | act.sa_flags = SA_SIGINFO; | |
105 | act.sa_sigaction = host_signal_handler; | |
106 | for(i = 1; i < NSIG; i++) { | |
107 | sigaction(i, &act, NULL); | |
108 | } | |
109 | ||
110 | memset(sigact_table, 0, sizeof(sigact_table)); | |
111 | ||
112 | first_free = &sigqueue_table[0]; | |
113 | for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++) | |
114 | sigqueue_table[i].next = &sigqueue_table[i + 1]; | |
115 | sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL; | |
116 | } | |
117 | ||
118 | /* signal queue handling */ | |
119 | ||
120 | static inline struct sigqueue *alloc_sigqueue(void) | |
121 | { | |
122 | struct sigqueue *q = first_free; | |
123 | if (!q) | |
124 | return NULL; | |
125 | first_free = q->next; | |
126 | return q; | |
127 | } | |
128 | ||
129 | static inline void free_sigqueue(struct sigqueue *q) | |
130 | { | |
131 | q->next = first_free; | |
132 | first_free = q; | |
133 | } | |
134 | ||
135 | /* abort execution with signal */ | |
a5e50b26 | 136 | void QEMU_NORETURN force_sig(int sig) |
831b7825 TS |
137 | { |
138 | int host_sig; | |
139 | host_sig = target_to_host_signal(sig); | |
140 | fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n", | |
141 | sig, strsignal(host_sig)); | |
142 | _exit(-host_sig); | |
143 | } | |
144 | ||
145 | /* queue a signal so that it will be send to the virtual CPU as soon | |
146 | as possible */ | |
147 | int queue_signal(int sig, target_siginfo_t *info) | |
148 | { | |
149 | struct emulated_sigaction *k; | |
150 | struct sigqueue *q, **pq; | |
151 | target_ulong handler; | |
152 | ||
153 | #if defined(DEBUG_SIGNAL) | |
154 | fprintf(stderr, "queue_signal: sig=%d\n", | |
155 | sig); | |
156 | #endif | |
157 | k = &sigact_table[sig - 1]; | |
158 | handler = (target_ulong)k->sa.sa_handler; | |
159 | if (handler == SIG_DFL) { | |
160 | /* default handler : ignore some signal. The other are fatal */ | |
161 | if (sig != SIGCHLD && | |
162 | sig != SIGURG && | |
163 | sig != SIGWINCH) { | |
164 | force_sig(sig); | |
165 | } else { | |
166 | return 0; /* indicate ignored */ | |
167 | } | |
168 | } else if (handler == host_to_target_signal(SIG_IGN)) { | |
169 | /* ignore signal */ | |
170 | return 0; | |
171 | } else if (handler == host_to_target_signal(SIG_ERR)) { | |
172 | force_sig(sig); | |
173 | } else { | |
174 | pq = &k->first; | |
175 | if (!k->pending) { | |
176 | /* first signal */ | |
177 | q = &k->info; | |
178 | } else { | |
179 | q = alloc_sigqueue(); | |
180 | if (!q) | |
181 | return -EAGAIN; | |
182 | while (*pq != NULL) | |
183 | pq = &(*pq)->next; | |
184 | } | |
185 | *pq = q; | |
186 | q->info = *info; | |
187 | q->next = NULL; | |
188 | k->pending = 1; | |
189 | /* signal that a new signal is pending */ | |
190 | signal_pending = 1; | |
191 | return 1; /* indicates that the signal was queued */ | |
192 | } | |
193 | } | |
194 | ||
195 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
196 | void *puc) | |
197 | { | |
198 | int sig; | |
199 | target_siginfo_t tinfo; | |
200 | ||
201 | /* the CPU emulator uses some host signals to detect exceptions, | |
202 | we we forward to it some signals */ | |
ec6338ba | 203 | if (host_signum == SIGSEGV || host_signum == SIGBUS) { |
831b7825 TS |
204 | if (cpu_signal_handler(host_signum, (void*)info, puc)) |
205 | return; | |
206 | } | |
207 | ||
208 | /* get target signal number */ | |
209 | sig = host_to_target_signal(host_signum); | |
210 | if (sig < 1 || sig > NSIG) | |
211 | return; | |
212 | ||
213 | #if defined(DEBUG_SIGNAL) | |
214 | fprintf(stderr, "qemu: got signal %d\n", sig); | |
215 | #endif | |
216 | if (queue_signal(sig, &tinfo) == 1) { | |
217 | /* interrupt the virtual CPU as soon as possible */ | |
3098dba0 | 218 | cpu_exit(global_env); |
831b7825 TS |
219 | } |
220 | } | |
221 | ||
222 | int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss) | |
223 | { | |
224 | /* XXX: test errors */ | |
225 | if(oss) | |
226 | { | |
227 | oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp); | |
228 | oss->ss_size = tswap32(target_sigaltstack_used.ss_size); | |
229 | oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags); | |
230 | } | |
231 | if(ss) | |
232 | { | |
233 | target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp); | |
234 | target_sigaltstack_used.ss_size = tswap32(ss->ss_size); | |
235 | target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags); | |
236 | } | |
237 | return 0; | |
238 | } | |
239 | ||
240 | int do_sigaction(int sig, const struct sigaction *act, | |
241 | struct sigaction *oact) | |
242 | { | |
243 | struct emulated_sigaction *k; | |
244 | struct sigaction act1; | |
245 | int host_sig; | |
246 | ||
247 | if (sig < 1 || sig > NSIG) | |
248 | return -EINVAL; | |
249 | ||
250 | k = &sigact_table[sig - 1]; | |
251 | #if defined(DEBUG_SIGNAL) | |
252 | fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n", | |
253 | sig, (int)act, (int)oact); | |
254 | #endif | |
255 | if (oact) { | |
256 | #if defined(DEBUG_SIGNAL) | |
257 | fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n", | |
258 | sig, (int)act, (int)oact); | |
259 | #endif | |
260 | ||
261 | oact->sa_handler = tswapl(k->sa.sa_handler); | |
262 | oact->sa_flags = tswapl(k->sa.sa_flags); | |
263 | oact->sa_mask = tswapl(k->sa.sa_mask); | |
264 | } | |
265 | if (act) { | |
266 | #if defined(DEBUG_SIGNAL) | |
267 | fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n", | |
268 | act->sa_handler, act->sa_flags, act->sa_mask); | |
269 | #endif | |
270 | ||
271 | k->sa.sa_handler = tswapl(act->sa_handler); | |
272 | k->sa.sa_flags = tswapl(act->sa_flags); | |
273 | k->sa.sa_mask = tswapl(act->sa_mask); | |
274 | /* we update the host signal state */ | |
275 | host_sig = target_to_host_signal(sig); | |
276 | if (host_sig != SIGSEGV && host_sig != SIGBUS) { | |
277 | #if defined(DEBUG_SIGNAL) | |
278 | fprintf(stderr, "sigaction handler going to call sigaction\n", | |
279 | act->sa_handler, act->sa_flags, act->sa_mask); | |
280 | #endif | |
281 | ||
282 | sigfillset(&act1.sa_mask); | |
283 | act1.sa_flags = SA_SIGINFO; | |
284 | if (k->sa.sa_flags & SA_RESTART) | |
285 | act1.sa_flags |= SA_RESTART; | |
286 | /* NOTE: it is important to update the host kernel signal | |
287 | ignore state to avoid getting unexpected interrupted | |
288 | syscalls */ | |
289 | if (k->sa.sa_handler == SIG_IGN) { | |
290 | act1.sa_sigaction = (void *)SIG_IGN; | |
291 | } else if (k->sa.sa_handler == SIG_DFL) { | |
292 | act1.sa_sigaction = (void *)SIG_DFL; | |
293 | } else { | |
294 | act1.sa_sigaction = host_signal_handler; | |
295 | } | |
296 | sigaction(host_sig, &act1, NULL); | |
297 | } | |
298 | } | |
299 | return 0; | |
300 | } | |
301 | ||
302 | ||
303 | #ifdef TARGET_I386 | |
304 | ||
305 | static inline void * | |
306 | get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size) | |
307 | { | |
308 | /* XXX Fix that */ | |
309 | if(target_sigaltstack_used.ss_flags & SA_DISABLE) | |
310 | { | |
311 | int esp; | |
312 | /* Default to using normal stack */ | |
313 | esp = env->regs[R_ESP]; | |
314 | ||
315 | return (void *)((esp - frame_size) & -8ul); | |
316 | } | |
317 | else | |
318 | { | |
319 | return target_sigaltstack_used.ss_sp; | |
320 | } | |
321 | } | |
322 | ||
323 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
324 | void *set, CPUState *env) | |
325 | { | |
326 | void *frame; | |
327 | int i, err = 0; | |
328 | ||
329 | fprintf(stderr, "setup_frame %d\n", sig); | |
330 | frame = get_sigframe(ka, env, sizeof(*frame)); | |
331 | ||
332 | /* Set up registers for signal handler */ | |
333 | env->regs[R_ESP] = (unsigned long) frame; | |
334 | env->eip = (unsigned long) ka->sa.sa_handler; | |
335 | ||
336 | env->eflags &= ~TF_MASK; | |
337 | ||
338 | return; | |
339 | ||
340 | give_sigsegv: | |
341 | if (sig == SIGSEGV) | |
342 | ka->sa.sa_handler = SIG_DFL; | |
343 | force_sig(SIGSEGV /* , current */); | |
344 | } | |
345 | ||
346 | long do_sigreturn(CPUState *env, int num) | |
347 | { | |
348 | int i = 0; | |
349 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
350 | /* XXX Get current signal number */ | |
351 | /* XXX Adjust accordin to sc_onstack, sc_mask */ | |
352 | if(tswapl(scp->sc_onstack) & 0x1) | |
353 | target_sigaltstack_used.ss_flags |= ~SA_DISABLE; | |
354 | else | |
355 | target_sigaltstack_used.ss_flags &= SA_DISABLE; | |
356 | int set = tswapl(scp->sc_eax); | |
357 | sigprocmask(SIG_SETMASK, &set, NULL); | |
358 | ||
359 | fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx)); | |
360 | fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi)); | |
361 | fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip)); | |
362 | ||
363 | env->regs[R_EAX] = tswapl(scp->sc_eax); | |
364 | env->regs[R_EBX] = tswapl(scp->sc_ebx); | |
365 | env->regs[R_ECX] = tswapl(scp->sc_ecx); | |
366 | env->regs[R_EDX] = tswapl(scp->sc_edx); | |
367 | env->regs[R_EDI] = tswapl(scp->sc_edi); | |
368 | env->regs[R_ESI] = tswapl(scp->sc_esi); | |
369 | env->regs[R_EBP] = tswapl(scp->sc_ebp); | |
370 | env->regs[R_ESP] = tswapl(scp->sc_esp); | |
371 | env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss); | |
372 | env->eflags = tswapl(scp->sc_eflags); | |
373 | env->eip = tswapl(scp->sc_eip); | |
374 | env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs); | |
375 | env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds); | |
376 | env->segs[R_ES].selector = (void*)tswapl(scp->sc_es); | |
377 | env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs); | |
378 | env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs); | |
379 | ||
380 | /* Again, because our caller's caller will reset EAX */ | |
381 | return env->regs[R_EAX]; | |
382 | } | |
383 | ||
384 | #else | |
385 | ||
386 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
387 | void *set, CPUState *env) | |
388 | { | |
389 | fprintf(stderr, "setup_frame: not implemented\n"); | |
390 | } | |
391 | ||
392 | long do_sigreturn(CPUState *env, int num) | |
393 | { | |
394 | int i = 0; | |
395 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
396 | fprintf(stderr, "do_sigreturn: not implemented\n"); | |
397 | return -ENOSYS; | |
398 | } | |
399 | ||
400 | #endif | |
401 | ||
402 | void process_pending_signals(void *cpu_env) | |
403 | { | |
404 | struct emulated_sigaction *k; | |
405 | struct sigqueue *q; | |
406 | target_ulong handler; | |
407 | int sig; | |
408 | ||
409 | if (!signal_pending) | |
410 | return; | |
411 | ||
412 | k = sigact_table; | |
413 | ||
414 | for(sig = 1; sig <= NSIG; sig++) { | |
415 | if (k->pending) | |
416 | goto handle_signal; | |
417 | k++; | |
418 | } | |
419 | ||
420 | /* if no signal is pending, just return */ | |
421 | signal_pending = 0; | |
422 | return; | |
423 | handle_signal: | |
424 | #ifdef DEBUG_SIGNAL | |
425 | fprintf(stderr, "qemu: process signal %d\n", sig); | |
426 | #endif | |
427 | /* dequeue signal */ | |
428 | q = k->first; | |
429 | k->first = q->next; | |
430 | if (!k->first) | |
431 | k->pending = 0; | |
432 | ||
433 | sig = gdb_handlesig (cpu_env, sig); | |
434 | if (!sig) { | |
435 | fprintf (stderr, "Lost signal\n"); | |
436 | abort(); | |
437 | } | |
438 | ||
439 | handler = k->sa.sa_handler; | |
440 | if (handler == SIG_DFL) { | |
441 | /* default handler : ignore some signal. The other are fatal */ | |
442 | if (sig != SIGCHLD && | |
443 | sig != SIGURG && | |
444 | sig != SIGWINCH) { | |
445 | force_sig(sig); | |
446 | } | |
447 | } else if (handler == SIG_IGN) { | |
448 | /* ignore sig */ | |
449 | } else if (handler == SIG_ERR) { | |
450 | force_sig(sig); | |
451 | } else { | |
452 | ||
453 | setup_frame(sig, k, 0, cpu_env); | |
454 | if (k->sa.sa_flags & SA_RESETHAND) | |
455 | k->sa.sa_handler = SIG_DFL; | |
456 | } | |
457 | if (q != &k->info) | |
458 | free_sigqueue(q); | |
459 | } |