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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 | |
8167ee88 | 17 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
831b7825 TS |
18 | */ |
19 | #include <stdlib.h> | |
20 | #include <stdio.h> | |
21 | #include <string.h> | |
22 | #include <stdarg.h> | |
23 | #include <unistd.h> | |
831b7825 TS |
24 | #include <errno.h> |
25 | #include <sys/ucontext.h> | |
26 | ||
27 | #ifdef __ia64__ | |
28 | #undef uc_mcontext | |
29 | #undef uc_sigmask | |
30 | #undef uc_stack | |
31 | #undef uc_link | |
32 | #endif | |
33 | ||
831b7825 | 34 | #include "qemu.h" |
7d99a001 | 35 | #include "qemu-common.h" |
831b7825 TS |
36 | |
37 | #define DEBUG_SIGNAL | |
38 | ||
39 | #define MAX_SIGQUEUE_SIZE 1024 | |
40 | ||
41 | struct sigqueue { | |
42 | struct sigqueue *next; | |
43 | target_siginfo_t info; | |
44 | }; | |
45 | ||
46 | struct emulated_sigaction { | |
47 | struct target_sigaction sa; | |
48 | int pending; /* true if signal is pending */ | |
49 | struct sigqueue *first; | |
50 | struct sigqueue info; /* in order to always have memory for the | |
51 | first signal, we put it here */ | |
52 | }; | |
53 | ||
249c4c32 | 54 | static struct sigaltstack target_sigaltstack_used = { |
831b7825 TS |
55 | 0, 0, SA_DISABLE |
56 | }; | |
57 | ||
58 | static struct emulated_sigaction sigact_table[NSIG]; | |
59 | static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */ | |
60 | static struct sigqueue *first_free; /* first free siginfo queue entry */ | |
61 | static int signal_pending; /* non zero if a signal may be pending */ | |
62 | ||
63 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
64 | void *puc); | |
65 | ||
66 | ||
67 | static inline int host_to_target_signal(int sig) | |
68 | { | |
69 | return sig; | |
70 | } | |
71 | ||
72 | static inline int target_to_host_signal(int sig) | |
73 | { | |
74 | return sig; | |
75 | } | |
76 | ||
77 | /* siginfo conversion */ | |
78 | ||
79 | ||
80 | ||
81 | void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) | |
82 | { | |
83 | ||
84 | } | |
85 | ||
86 | void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo) | |
87 | { | |
88 | ||
89 | } | |
90 | ||
91 | void signal_init(void) | |
92 | { | |
93 | struct sigaction act; | |
94 | int i; | |
95 | ||
96 | /* set all host signal handlers. ALL signals are blocked during | |
97 | the handlers to serialize them. */ | |
98 | sigfillset(&act.sa_mask); | |
99 | act.sa_flags = SA_SIGINFO; | |
100 | act.sa_sigaction = host_signal_handler; | |
101 | for(i = 1; i < NSIG; i++) { | |
102 | sigaction(i, &act, NULL); | |
103 | } | |
104 | ||
105 | memset(sigact_table, 0, sizeof(sigact_table)); | |
106 | ||
107 | first_free = &sigqueue_table[0]; | |
108 | for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++) | |
109 | sigqueue_table[i].next = &sigqueue_table[i + 1]; | |
110 | sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL; | |
111 | } | |
112 | ||
113 | /* signal queue handling */ | |
114 | ||
115 | static inline struct sigqueue *alloc_sigqueue(void) | |
116 | { | |
117 | struct sigqueue *q = first_free; | |
118 | if (!q) | |
119 | return NULL; | |
120 | first_free = q->next; | |
121 | return q; | |
122 | } | |
123 | ||
124 | static inline void free_sigqueue(struct sigqueue *q) | |
125 | { | |
126 | q->next = first_free; | |
127 | first_free = q; | |
128 | } | |
129 | ||
130 | /* abort execution with signal */ | |
a5e50b26 | 131 | void QEMU_NORETURN force_sig(int sig) |
831b7825 TS |
132 | { |
133 | int host_sig; | |
134 | host_sig = target_to_host_signal(sig); | |
135 | fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n", | |
136 | sig, strsignal(host_sig)); | |
137 | _exit(-host_sig); | |
138 | } | |
139 | ||
140 | /* queue a signal so that it will be send to the virtual CPU as soon | |
141 | as possible */ | |
142 | int queue_signal(int sig, target_siginfo_t *info) | |
143 | { | |
144 | struct emulated_sigaction *k; | |
145 | struct sigqueue *q, **pq; | |
146 | target_ulong handler; | |
147 | ||
148 | #if defined(DEBUG_SIGNAL) | |
149 | fprintf(stderr, "queue_signal: sig=%d\n", | |
150 | sig); | |
151 | #endif | |
152 | k = &sigact_table[sig - 1]; | |
153 | handler = (target_ulong)k->sa.sa_handler; | |
154 | if (handler == SIG_DFL) { | |
155 | /* default handler : ignore some signal. The other are fatal */ | |
156 | if (sig != SIGCHLD && | |
157 | sig != SIGURG && | |
158 | sig != SIGWINCH) { | |
159 | force_sig(sig); | |
160 | } else { | |
161 | return 0; /* indicate ignored */ | |
162 | } | |
163 | } else if (handler == host_to_target_signal(SIG_IGN)) { | |
164 | /* ignore signal */ | |
165 | return 0; | |
166 | } else if (handler == host_to_target_signal(SIG_ERR)) { | |
167 | force_sig(sig); | |
168 | } else { | |
169 | pq = &k->first; | |
170 | if (!k->pending) { | |
171 | /* first signal */ | |
172 | q = &k->info; | |
173 | } else { | |
174 | q = alloc_sigqueue(); | |
175 | if (!q) | |
176 | return -EAGAIN; | |
177 | while (*pq != NULL) | |
178 | pq = &(*pq)->next; | |
179 | } | |
180 | *pq = q; | |
181 | q->info = *info; | |
182 | q->next = NULL; | |
183 | k->pending = 1; | |
184 | /* signal that a new signal is pending */ | |
185 | signal_pending = 1; | |
186 | return 1; /* indicates that the signal was queued */ | |
187 | } | |
188 | } | |
189 | ||
190 | static void host_signal_handler(int host_signum, siginfo_t *info, | |
191 | void *puc) | |
192 | { | |
193 | int sig; | |
194 | target_siginfo_t tinfo; | |
195 | ||
196 | /* the CPU emulator uses some host signals to detect exceptions, | |
197 | we we forward to it some signals */ | |
ec6338ba | 198 | if (host_signum == SIGSEGV || host_signum == SIGBUS) { |
831b7825 TS |
199 | if (cpu_signal_handler(host_signum, (void*)info, puc)) |
200 | return; | |
201 | } | |
202 | ||
203 | /* get target signal number */ | |
204 | sig = host_to_target_signal(host_signum); | |
205 | if (sig < 1 || sig > NSIG) | |
206 | return; | |
207 | ||
208 | #if defined(DEBUG_SIGNAL) | |
209 | fprintf(stderr, "qemu: got signal %d\n", sig); | |
210 | #endif | |
211 | if (queue_signal(sig, &tinfo) == 1) { | |
212 | /* interrupt the virtual CPU as soon as possible */ | |
3098dba0 | 213 | cpu_exit(global_env); |
831b7825 TS |
214 | } |
215 | } | |
216 | ||
217 | int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss) | |
218 | { | |
219 | /* XXX: test errors */ | |
220 | if(oss) | |
221 | { | |
222 | oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp); | |
223 | oss->ss_size = tswap32(target_sigaltstack_used.ss_size); | |
224 | oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags); | |
225 | } | |
226 | if(ss) | |
227 | { | |
228 | target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp); | |
229 | target_sigaltstack_used.ss_size = tswap32(ss->ss_size); | |
230 | target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags); | |
231 | } | |
232 | return 0; | |
233 | } | |
234 | ||
235 | int do_sigaction(int sig, const struct sigaction *act, | |
236 | struct sigaction *oact) | |
237 | { | |
238 | struct emulated_sigaction *k; | |
239 | struct sigaction act1; | |
240 | int host_sig; | |
241 | ||
242 | if (sig < 1 || sig > NSIG) | |
243 | return -EINVAL; | |
244 | ||
245 | k = &sigact_table[sig - 1]; | |
246 | #if defined(DEBUG_SIGNAL) | |
247 | fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n", | |
248 | sig, (int)act, (int)oact); | |
249 | #endif | |
250 | if (oact) { | |
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 | ||
256 | oact->sa_handler = tswapl(k->sa.sa_handler); | |
257 | oact->sa_flags = tswapl(k->sa.sa_flags); | |
258 | oact->sa_mask = tswapl(k->sa.sa_mask); | |
259 | } | |
260 | if (act) { | |
261 | #if defined(DEBUG_SIGNAL) | |
262 | fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n", | |
263 | act->sa_handler, act->sa_flags, act->sa_mask); | |
264 | #endif | |
265 | ||
266 | k->sa.sa_handler = tswapl(act->sa_handler); | |
267 | k->sa.sa_flags = tswapl(act->sa_flags); | |
268 | k->sa.sa_mask = tswapl(act->sa_mask); | |
269 | /* we update the host signal state */ | |
270 | host_sig = target_to_host_signal(sig); | |
271 | if (host_sig != SIGSEGV && host_sig != SIGBUS) { | |
272 | #if defined(DEBUG_SIGNAL) | |
273 | fprintf(stderr, "sigaction handler going to call sigaction\n", | |
274 | act->sa_handler, act->sa_flags, act->sa_mask); | |
275 | #endif | |
276 | ||
277 | sigfillset(&act1.sa_mask); | |
278 | act1.sa_flags = SA_SIGINFO; | |
279 | if (k->sa.sa_flags & SA_RESTART) | |
280 | act1.sa_flags |= SA_RESTART; | |
281 | /* NOTE: it is important to update the host kernel signal | |
282 | ignore state to avoid getting unexpected interrupted | |
283 | syscalls */ | |
284 | if (k->sa.sa_handler == SIG_IGN) { | |
285 | act1.sa_sigaction = (void *)SIG_IGN; | |
286 | } else if (k->sa.sa_handler == SIG_DFL) { | |
287 | act1.sa_sigaction = (void *)SIG_DFL; | |
288 | } else { | |
289 | act1.sa_sigaction = host_signal_handler; | |
290 | } | |
291 | sigaction(host_sig, &act1, NULL); | |
292 | } | |
293 | } | |
294 | return 0; | |
295 | } | |
296 | ||
297 | ||
298 | #ifdef TARGET_I386 | |
299 | ||
300 | static inline void * | |
301 | get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size) | |
302 | { | |
303 | /* XXX Fix that */ | |
304 | if(target_sigaltstack_used.ss_flags & SA_DISABLE) | |
305 | { | |
306 | int esp; | |
307 | /* Default to using normal stack */ | |
308 | esp = env->regs[R_ESP]; | |
309 | ||
310 | return (void *)((esp - frame_size) & -8ul); | |
311 | } | |
312 | else | |
313 | { | |
314 | return target_sigaltstack_used.ss_sp; | |
315 | } | |
316 | } | |
317 | ||
318 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
319 | void *set, CPUState *env) | |
320 | { | |
321 | void *frame; | |
831b7825 TS |
322 | |
323 | fprintf(stderr, "setup_frame %d\n", sig); | |
324 | frame = get_sigframe(ka, env, sizeof(*frame)); | |
325 | ||
326 | /* Set up registers for signal handler */ | |
327 | env->regs[R_ESP] = (unsigned long) frame; | |
328 | env->eip = (unsigned long) ka->sa.sa_handler; | |
329 | ||
330 | env->eflags &= ~TF_MASK; | |
331 | ||
332 | return; | |
333 | ||
334 | give_sigsegv: | |
335 | if (sig == SIGSEGV) | |
336 | ka->sa.sa_handler = SIG_DFL; | |
337 | force_sig(SIGSEGV /* , current */); | |
338 | } | |
339 | ||
340 | long do_sigreturn(CPUState *env, int num) | |
341 | { | |
342 | int i = 0; | |
343 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
344 | /* XXX Get current signal number */ | |
345 | /* XXX Adjust accordin to sc_onstack, sc_mask */ | |
346 | if(tswapl(scp->sc_onstack) & 0x1) | |
347 | target_sigaltstack_used.ss_flags |= ~SA_DISABLE; | |
348 | else | |
349 | target_sigaltstack_used.ss_flags &= SA_DISABLE; | |
350 | int set = tswapl(scp->sc_eax); | |
351 | sigprocmask(SIG_SETMASK, &set, NULL); | |
352 | ||
353 | fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx)); | |
354 | fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi)); | |
355 | fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip)); | |
356 | ||
357 | env->regs[R_EAX] = tswapl(scp->sc_eax); | |
358 | env->regs[R_EBX] = tswapl(scp->sc_ebx); | |
359 | env->regs[R_ECX] = tswapl(scp->sc_ecx); | |
360 | env->regs[R_EDX] = tswapl(scp->sc_edx); | |
361 | env->regs[R_EDI] = tswapl(scp->sc_edi); | |
362 | env->regs[R_ESI] = tswapl(scp->sc_esi); | |
363 | env->regs[R_EBP] = tswapl(scp->sc_ebp); | |
364 | env->regs[R_ESP] = tswapl(scp->sc_esp); | |
365 | env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss); | |
366 | env->eflags = tswapl(scp->sc_eflags); | |
367 | env->eip = tswapl(scp->sc_eip); | |
368 | env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs); | |
369 | env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds); | |
370 | env->segs[R_ES].selector = (void*)tswapl(scp->sc_es); | |
371 | env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs); | |
372 | env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs); | |
373 | ||
374 | /* Again, because our caller's caller will reset EAX */ | |
375 | return env->regs[R_EAX]; | |
376 | } | |
377 | ||
378 | #else | |
379 | ||
380 | static void setup_frame(int sig, struct emulated_sigaction *ka, | |
381 | void *set, CPUState *env) | |
382 | { | |
383 | fprintf(stderr, "setup_frame: not implemented\n"); | |
384 | } | |
385 | ||
386 | long do_sigreturn(CPUState *env, int num) | |
387 | { | |
388 | int i = 0; | |
389 | struct target_sigcontext *scp = get_int_arg(&i, env); | |
390 | fprintf(stderr, "do_sigreturn: not implemented\n"); | |
391 | return -ENOSYS; | |
392 | } | |
393 | ||
394 | #endif | |
395 | ||
396 | void process_pending_signals(void *cpu_env) | |
397 | { | |
398 | struct emulated_sigaction *k; | |
399 | struct sigqueue *q; | |
400 | target_ulong handler; | |
401 | int sig; | |
402 | ||
403 | if (!signal_pending) | |
404 | return; | |
405 | ||
406 | k = sigact_table; | |
407 | ||
408 | for(sig = 1; sig <= NSIG; sig++) { | |
409 | if (k->pending) | |
410 | goto handle_signal; | |
411 | k++; | |
412 | } | |
413 | ||
414 | /* if no signal is pending, just return */ | |
415 | signal_pending = 0; | |
416 | return; | |
417 | handle_signal: | |
418 | #ifdef DEBUG_SIGNAL | |
419 | fprintf(stderr, "qemu: process signal %d\n", sig); | |
420 | #endif | |
421 | /* dequeue signal */ | |
422 | q = k->first; | |
423 | k->first = q->next; | |
424 | if (!k->first) | |
425 | k->pending = 0; | |
426 | ||
427 | sig = gdb_handlesig (cpu_env, sig); | |
428 | if (!sig) { | |
429 | fprintf (stderr, "Lost signal\n"); | |
430 | abort(); | |
431 | } | |
432 | ||
433 | handler = k->sa.sa_handler; | |
434 | if (handler == SIG_DFL) { | |
435 | /* default handler : ignore some signal. The other are fatal */ | |
436 | if (sig != SIGCHLD && | |
437 | sig != SIGURG && | |
438 | sig != SIGWINCH) { | |
439 | force_sig(sig); | |
440 | } | |
441 | } else if (handler == SIG_IGN) { | |
442 | /* ignore sig */ | |
443 | } else if (handler == SIG_ERR) { | |
444 | force_sig(sig); | |
445 | } else { | |
446 | ||
447 | setup_frame(sig, k, 0, cpu_env); | |
448 | if (k->sa.sa_flags & SA_RESETHAND) | |
449 | k->sa.sa_handler = SIG_DFL; | |
450 | } | |
451 | if (q != &k->info) | |
452 | free_sigqueue(q); | |
453 | } |