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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 | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | #include <stdlib.h> | |
21 | #include <stdio.h> | |
22 | #include <string.h> | |
23 | #include <stdarg.h> | |
24 | #include <unistd.h> | |
25 | #include <signal.h> | |
26 | #include <errno.h> | |
27 | #include <sys/ucontext.h> | |
28 | ||
29 | #ifdef __ia64__ | |
30 | #undef uc_mcontext | |
31 | #undef uc_sigmask | |
32 | #undef uc_stack | |
33 | #undef uc_link | |
34 | #endif | |
35 | ||
36 | #include <signal.h> | |
37 | ||
38 | #include "qemu.h" | |
39 | ||
40 | #define DEBUG_SIGNAL | |
41 | ||
42 | #define MAX_SIGQUEUE_SIZE 1024 | |
43 | ||
44 | struct sigqueue { | |
45 | struct sigqueue *next; | |
46 | target_siginfo_t info; | |
47 | }; | |
48 | ||
49 | struct emulated_sigaction { | |
50 | struct target_sigaction sa; | |
51 | int pending; /* true if signal is pending */ | |
52 | struct sigqueue *first; | |
53 | struct sigqueue info; /* in order to always have memory for the | |
54 | first signal, we put it here */ | |
55 | }; | |
56 | ||
57 | struct sigaltstack target_sigaltstack_used = { | |
58 | 0, 0, SA_DISABLE | |
59 | }; | |
60 | ||
61 | static struct emulated_sigaction sigact_table[NSIG]; | |
62 | static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */ | |
63 | static struct sigqueue *first_free; /* first free siginfo queue entry */ | |
64 | static int signal_pending; /* non zero if a signal may be pending */ | |
65 | ||
66 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
67 | void *puc); | |
68 | ||
69 | ||
70 | static inline int host_to_target_signal(int sig) | |
71 | { | |
72 | return sig; | |
73 | } | |
74 | ||
75 | static inline int target_to_host_signal(int sig) | |
76 | { | |
77 | return sig; | |
78 | } | |
79 | ||
80 | /* siginfo conversion */ | |
81 | ||
82 | ||
83 | ||
84 | void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) | |
85 | { | |
86 | ||
87 | } | |
88 | ||
89 | void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) | |
90 | { | |
91 | ||
92 | } | |
93 | ||
94 | void signal_init(void) | |
95 | { | |
96 | struct sigaction act; | |
97 | int i; | |
98 | ||
99 | /* set all host signal handlers. ALL signals are blocked during | |
100 | the handlers to serialize them. */ | |
101 | sigfillset(&act.sa_mask); | |
102 | act.sa_flags = SA_SIGINFO; | |
103 | act.sa_sigaction = host_signal_handler; | |
104 | for(i = 1; i < NSIG; i++) { | |
105 | sigaction(i, &act, NULL); | |
106 | } | |
107 | ||
108 | memset(sigact_table, 0, sizeof(sigact_table)); | |
109 | ||
110 | first_free = &sigqueue_table[0]; | |
111 | for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++) | |
112 | sigqueue_table[i].next = &sigqueue_table[i + 1]; | |
113 | sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL; | |
114 | } | |
115 | ||
116 | /* signal queue handling */ | |
117 | ||
118 | static inline struct sigqueue *alloc_sigqueue(void) | |
119 | { | |
120 | struct sigqueue *q = first_free; | |
121 | if (!q) | |
122 | return NULL; | |
123 | first_free = q->next; | |
124 | return q; | |
125 | } | |
126 | ||
127 | static inline void free_sigqueue(struct sigqueue *q) | |
128 | { | |
129 | q->next = first_free; | |
130 | first_free = q; | |
131 | } | |
132 | ||
133 | /* abort execution with signal */ | |
134 | void __attribute((noreturn)) force_sig(int sig) | |
135 | { | |
136 | int host_sig; | |
137 | host_sig = target_to_host_signal(sig); | |
138 | fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n", | |
139 | sig, strsignal(host_sig)); | |
140 | _exit(-host_sig); | |
141 | } | |
142 | ||
143 | /* queue a signal so that it will be send to the virtual CPU as soon | |
144 | as possible */ | |
145 | int queue_signal(int sig, target_siginfo_t *info) | |
146 | { | |
147 | struct emulated_sigaction *k; | |
148 | struct sigqueue *q, **pq; | |
149 | target_ulong handler; | |
150 | ||
151 | #if defined(DEBUG_SIGNAL) | |
152 | fprintf(stderr, "queue_signal: sig=%d\n", | |
153 | sig); | |
154 | #endif | |
155 | k = &sigact_table[sig - 1]; | |
156 | handler = (target_ulong)k->sa.sa_handler; | |
157 | if (handler == SIG_DFL) { | |
158 | /* default handler : ignore some signal. The other are fatal */ | |
159 | if (sig != SIGCHLD && | |
160 | sig != SIGURG && | |
161 | sig != SIGWINCH) { | |
162 | force_sig(sig); | |
163 | } else { | |
164 | return 0; /* indicate ignored */ | |
165 | } | |
166 | } else if (handler == host_to_target_signal(SIG_IGN)) { | |
167 | /* ignore signal */ | |
168 | return 0; | |
169 | } else if (handler == host_to_target_signal(SIG_ERR)) { | |
170 | force_sig(sig); | |
171 | } else { | |
172 | pq = &k->first; | |
173 | if (!k->pending) { | |
174 | /* first signal */ | |
175 | q = &k->info; | |
176 | } else { | |
177 | q = alloc_sigqueue(); | |
178 | if (!q) | |
179 | return -EAGAIN; | |
180 | while (*pq != NULL) | |
181 | pq = &(*pq)->next; | |
182 | } | |
183 | *pq = q; | |
184 | q->info = *info; | |
185 | q->next = NULL; | |
186 | k->pending = 1; | |
187 | /* signal that a new signal is pending */ | |
188 | signal_pending = 1; | |
189 | return 1; /* indicates that the signal was queued */ | |
190 | } | |
191 | } | |
192 | ||
193 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
194 | void *puc) | |
195 | { | |
196 | int sig; | |
197 | target_siginfo_t tinfo; | |
198 | ||
199 | /* the CPU emulator uses some host signals to detect exceptions, | |
200 | we we forward to it some signals */ | |
201 | if (host_signum == SIGSEGV || host_signum == SIGBUS | |
202 | #if defined(TARGET_I386) && defined(USE_CODE_COPY) | |
203 | || host_signum == SIGFPE | |
204 | #endif | |
205 | ) { | |
206 | if (cpu_signal_handler(host_signum, (void*)info, puc)) | |
207 | return; | |
208 | } | |
209 | ||
210 | /* get target signal number */ | |
211 | sig = host_to_target_signal(host_signum); | |
212 | if (sig < 1 || sig > NSIG) | |
213 | return; | |
214 | ||
215 | #if defined(DEBUG_SIGNAL) | |
216 | fprintf(stderr, "qemu: got signal %d\n", sig); | |
217 | #endif | |
218 | if (queue_signal(sig, &tinfo) == 1) { | |
219 | /* interrupt the virtual CPU as soon as possible */ | |
220 | cpu_interrupt(global_env, CPU_INTERRUPT_EXIT); | |
221 | } | |
222 | } | |
223 | ||
224 | int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss) | |
225 | { | |
226 | /* XXX: test errors */ | |
227 | if(oss) | |
228 | { | |
229 | oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp); | |
230 | oss->ss_size = tswap32(target_sigaltstack_used.ss_size); | |
231 | oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags); | |
232 | } | |
233 | if(ss) | |
234 | { | |
235 | target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp); | |
236 | target_sigaltstack_used.ss_size = tswap32(ss->ss_size); | |
237 | target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags); | |
238 | } | |
239 | return 0; | |
240 | } | |
241 | ||
242 | int do_sigaction(int sig, const struct sigaction *act, | |
243 | struct sigaction *oact) | |
244 | { | |
245 | struct emulated_sigaction *k; | |
246 | struct sigaction act1; | |
247 | int host_sig; | |
248 | ||
249 | if (sig < 1 || sig > NSIG) | |
250 | return -EINVAL; | |
251 | ||
252 | k = &sigact_table[sig - 1]; | |
253 | #if defined(DEBUG_SIGNAL) | |
254 | fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n", | |
255 | sig, (int)act, (int)oact); | |
256 | #endif | |
257 | if (oact) { | |
258 | #if defined(DEBUG_SIGNAL) | |
259 | fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n", | |
260 | sig, (int)act, (int)oact); | |
261 | #endif | |
262 | ||
263 | oact->sa_handler = tswapl(k->sa.sa_handler); | |
264 | oact->sa_flags = tswapl(k->sa.sa_flags); | |
265 | oact->sa_mask = tswapl(k->sa.sa_mask); | |
266 | } | |
267 | if (act) { | |
268 | #if defined(DEBUG_SIGNAL) | |
269 | fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n", | |
270 | act->sa_handler, act->sa_flags, act->sa_mask); | |
271 | #endif | |
272 | ||
273 | k->sa.sa_handler = tswapl(act->sa_handler); | |
274 | k->sa.sa_flags = tswapl(act->sa_flags); | |
275 | k->sa.sa_mask = tswapl(act->sa_mask); | |
276 | /* we update the host signal state */ | |
277 | host_sig = target_to_host_signal(sig); | |
278 | if (host_sig != SIGSEGV && host_sig != SIGBUS) { | |
279 | #if defined(DEBUG_SIGNAL) | |
280 | fprintf(stderr, "sigaction handler going to call sigaction\n", | |
281 | act->sa_handler, act->sa_flags, act->sa_mask); | |
282 | #endif | |
283 | ||
284 | sigfillset(&act1.sa_mask); | |
285 | act1.sa_flags = SA_SIGINFO; | |
286 | if (k->sa.sa_flags & SA_RESTART) | |
287 | act1.sa_flags |= SA_RESTART; | |
288 | /* NOTE: it is important to update the host kernel signal | |
289 | ignore state to avoid getting unexpected interrupted | |
290 | syscalls */ | |
291 | if (k->sa.sa_handler == SIG_IGN) { | |
292 | act1.sa_sigaction = (void *)SIG_IGN; | |
293 | } else if (k->sa.sa_handler == SIG_DFL) { | |
294 | act1.sa_sigaction = (void *)SIG_DFL; | |
295 | } else { | |
296 | act1.sa_sigaction = host_signal_handler; | |
297 | } | |
298 | sigaction(host_sig, &act1, NULL); | |
299 | } | |
300 | } | |
301 | return 0; | |
302 | } | |
303 | ||
304 | ||
305 | #ifdef TARGET_I386 | |
306 | ||
307 | static inline void * | |
308 | get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size) | |
309 | { | |
310 | /* XXX Fix that */ | |
311 | if(target_sigaltstack_used.ss_flags & SA_DISABLE) | |
312 | { | |
313 | int esp; | |
314 | /* Default to using normal stack */ | |
315 | esp = env->regs[R_ESP]; | |
316 | ||
317 | return (void *)((esp - frame_size) & -8ul); | |
318 | } | |
319 | else | |
320 | { | |
321 | return target_sigaltstack_used.ss_sp; | |
322 | } | |
323 | } | |
324 | ||
325 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
326 | void *set, CPUState *env) | |
327 | { | |
328 | void *frame; | |
329 | int i, err = 0; | |
330 | ||
331 | fprintf(stderr, "setup_frame %d\n", sig); | |
332 | frame = get_sigframe(ka, env, sizeof(*frame)); | |
333 | ||
334 | /* Set up registers for signal handler */ | |
335 | env->regs[R_ESP] = (unsigned long) frame; | |
336 | env->eip = (unsigned long) ka->sa.sa_handler; | |
337 | ||
338 | env->eflags &= ~TF_MASK; | |
339 | ||
340 | return; | |
341 | ||
342 | give_sigsegv: | |
343 | if (sig == SIGSEGV) | |
344 | ka->sa.sa_handler = SIG_DFL; | |
345 | force_sig(SIGSEGV /* , current */); | |
346 | } | |
347 | ||
348 | long do_sigreturn(CPUState *env, int num) | |
349 | { | |
350 | int i = 0; | |
351 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
352 | /* XXX Get current signal number */ | |
353 | /* XXX Adjust accordin to sc_onstack, sc_mask */ | |
354 | if(tswapl(scp->sc_onstack) & 0x1) | |
355 | target_sigaltstack_used.ss_flags |= ~SA_DISABLE; | |
356 | else | |
357 | target_sigaltstack_used.ss_flags &= SA_DISABLE; | |
358 | int set = tswapl(scp->sc_eax); | |
359 | sigprocmask(SIG_SETMASK, &set, NULL); | |
360 | ||
361 | fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx)); | |
362 | fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi)); | |
363 | fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip)); | |
364 | ||
365 | env->regs[R_EAX] = tswapl(scp->sc_eax); | |
366 | env->regs[R_EBX] = tswapl(scp->sc_ebx); | |
367 | env->regs[R_ECX] = tswapl(scp->sc_ecx); | |
368 | env->regs[R_EDX] = tswapl(scp->sc_edx); | |
369 | env->regs[R_EDI] = tswapl(scp->sc_edi); | |
370 | env->regs[R_ESI] = tswapl(scp->sc_esi); | |
371 | env->regs[R_EBP] = tswapl(scp->sc_ebp); | |
372 | env->regs[R_ESP] = tswapl(scp->sc_esp); | |
373 | env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss); | |
374 | env->eflags = tswapl(scp->sc_eflags); | |
375 | env->eip = tswapl(scp->sc_eip); | |
376 | env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs); | |
377 | env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds); | |
378 | env->segs[R_ES].selector = (void*)tswapl(scp->sc_es); | |
379 | env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs); | |
380 | env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs); | |
381 | ||
382 | /* Again, because our caller's caller will reset EAX */ | |
383 | return env->regs[R_EAX]; | |
384 | } | |
385 | ||
386 | #else | |
387 | ||
388 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
389 | void *set, CPUState *env) | |
390 | { | |
391 | fprintf(stderr, "setup_frame: not implemented\n"); | |
392 | } | |
393 | ||
394 | long do_sigreturn(CPUState *env, int num) | |
395 | { | |
396 | int i = 0; | |
397 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
398 | fprintf(stderr, "do_sigreturn: not implemented\n"); | |
399 | return -ENOSYS; | |
400 | } | |
401 | ||
402 | #endif | |
403 | ||
404 | void process_pending_signals(void *cpu_env) | |
405 | { | |
406 | struct emulated_sigaction *k; | |
407 | struct sigqueue *q; | |
408 | target_ulong handler; | |
409 | int sig; | |
410 | ||
411 | if (!signal_pending) | |
412 | return; | |
413 | ||
414 | k = sigact_table; | |
415 | ||
416 | for(sig = 1; sig <= NSIG; sig++) { | |
417 | if (k->pending) | |
418 | goto handle_signal; | |
419 | k++; | |
420 | } | |
421 | ||
422 | /* if no signal is pending, just return */ | |
423 | signal_pending = 0; | |
424 | return; | |
425 | handle_signal: | |
426 | #ifdef DEBUG_SIGNAL | |
427 | fprintf(stderr, "qemu: process signal %d\n", sig); | |
428 | #endif | |
429 | /* dequeue signal */ | |
430 | q = k->first; | |
431 | k->first = q->next; | |
432 | if (!k->first) | |
433 | k->pending = 0; | |
434 | ||
435 | sig = gdb_handlesig (cpu_env, sig); | |
436 | if (!sig) { | |
437 | fprintf (stderr, "Lost signal\n"); | |
438 | abort(); | |
439 | } | |
440 | ||
441 | handler = k->sa.sa_handler; | |
442 | if (handler == SIG_DFL) { | |
443 | /* default handler : ignore some signal. The other are fatal */ | |
444 | if (sig != SIGCHLD && | |
445 | sig != SIGURG && | |
446 | sig != SIGWINCH) { | |
447 | force_sig(sig); | |
448 | } | |
449 | } else if (handler == SIG_IGN) { | |
450 | /* ignore sig */ | |
451 | } else if (handler == SIG_ERR) { | |
452 | force_sig(sig); | |
453 | } else { | |
454 | ||
455 | setup_frame(sig, k, 0, cpu_env); | |
456 | if (k->sa.sa_flags & SA_RESETHAND) | |
457 | k->sa.sa_handler = SIG_DFL; | |
458 | } | |
459 | if (q != &k->info) | |
460 | free_sigqueue(q); | |
461 | } | |
462 | ||
463 |