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1.1 root 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:
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