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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 */
1.1.1.2 ! root 201: if (host_signum == SIGSEGV || host_signum == SIGBUS) {
1.1 root 202: if (cpu_signal_handler(host_signum, (void*)info, puc))
203: return;
204: }
205:
206: /* get target signal number */
207: sig = host_to_target_signal(host_signum);
208: if (sig < 1 || sig > NSIG)
209: return;
210:
211: #if defined(DEBUG_SIGNAL)
212: fprintf(stderr, "qemu: got signal %d\n", sig);
213: #endif
214: if (queue_signal(sig, &tinfo) == 1) {
215: /* interrupt the virtual CPU as soon as possible */
216: cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);
217: }
218: }
219:
220: int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss)
221: {
222: /* XXX: test errors */
223: if(oss)
224: {
225: oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
226: oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
227: oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
228: }
229: if(ss)
230: {
231: target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
232: target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
233: target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
234: }
235: return 0;
236: }
237:
238: int do_sigaction(int sig, const struct sigaction *act,
239: struct sigaction *oact)
240: {
241: struct emulated_sigaction *k;
242: struct sigaction act1;
243: int host_sig;
244:
245: if (sig < 1 || sig > NSIG)
246: return -EINVAL;
247:
248: k = &sigact_table[sig - 1];
249: #if defined(DEBUG_SIGNAL)
250: fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
251: sig, (int)act, (int)oact);
252: #endif
253: if (oact) {
254: #if defined(DEBUG_SIGNAL)
255: fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
256: sig, (int)act, (int)oact);
257: #endif
258:
259: oact->sa_handler = tswapl(k->sa.sa_handler);
260: oact->sa_flags = tswapl(k->sa.sa_flags);
261: oact->sa_mask = tswapl(k->sa.sa_mask);
262: }
263: if (act) {
264: #if defined(DEBUG_SIGNAL)
265: fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
266: act->sa_handler, act->sa_flags, act->sa_mask);
267: #endif
268:
269: k->sa.sa_handler = tswapl(act->sa_handler);
270: k->sa.sa_flags = tswapl(act->sa_flags);
271: k->sa.sa_mask = tswapl(act->sa_mask);
272: /* we update the host signal state */
273: host_sig = target_to_host_signal(sig);
274: if (host_sig != SIGSEGV && host_sig != SIGBUS) {
275: #if defined(DEBUG_SIGNAL)
276: fprintf(stderr, "sigaction handler going to call sigaction\n",
277: act->sa_handler, act->sa_flags, act->sa_mask);
278: #endif
279:
280: sigfillset(&act1.sa_mask);
281: act1.sa_flags = SA_SIGINFO;
282: if (k->sa.sa_flags & SA_RESTART)
283: act1.sa_flags |= SA_RESTART;
284: /* NOTE: it is important to update the host kernel signal
285: ignore state to avoid getting unexpected interrupted
286: syscalls */
287: if (k->sa.sa_handler == SIG_IGN) {
288: act1.sa_sigaction = (void *)SIG_IGN;
289: } else if (k->sa.sa_handler == SIG_DFL) {
290: act1.sa_sigaction = (void *)SIG_DFL;
291: } else {
292: act1.sa_sigaction = host_signal_handler;
293: }
294: sigaction(host_sig, &act1, NULL);
295: }
296: }
297: return 0;
298: }
299:
300:
301: #ifdef TARGET_I386
302:
303: static inline void *
304: get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
305: {
306: /* XXX Fix that */
307: if(target_sigaltstack_used.ss_flags & SA_DISABLE)
308: {
309: int esp;
310: /* Default to using normal stack */
311: esp = env->regs[R_ESP];
312:
313: return (void *)((esp - frame_size) & -8ul);
314: }
315: else
316: {
317: return target_sigaltstack_used.ss_sp;
318: }
319: }
320:
321: static void setup_frame(int sig, struct emulated_sigaction *ka,
322: void *set, CPUState *env)
323: {
324: void *frame;
325: int i, err = 0;
326:
327: fprintf(stderr, "setup_frame %d\n", sig);
328: frame = get_sigframe(ka, env, sizeof(*frame));
329:
330: /* Set up registers for signal handler */
331: env->regs[R_ESP] = (unsigned long) frame;
332: env->eip = (unsigned long) ka->sa.sa_handler;
333:
334: env->eflags &= ~TF_MASK;
335:
336: return;
337:
338: give_sigsegv:
339: if (sig == SIGSEGV)
340: ka->sa.sa_handler = SIG_DFL;
341: force_sig(SIGSEGV /* , current */);
342: }
343:
344: long do_sigreturn(CPUState *env, int num)
345: {
346: int i = 0;
347: struct target_sigcontext *scp = get_int_arg(&i, env);
348: /* XXX Get current signal number */
349: /* XXX Adjust accordin to sc_onstack, sc_mask */
350: if(tswapl(scp->sc_onstack) & 0x1)
351: target_sigaltstack_used.ss_flags |= ~SA_DISABLE;
352: else
353: target_sigaltstack_used.ss_flags &= SA_DISABLE;
354: int set = tswapl(scp->sc_eax);
355: sigprocmask(SIG_SETMASK, &set, NULL);
356:
357: fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
358: fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
359: fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));
360:
361: env->regs[R_EAX] = tswapl(scp->sc_eax);
362: env->regs[R_EBX] = tswapl(scp->sc_ebx);
363: env->regs[R_ECX] = tswapl(scp->sc_ecx);
364: env->regs[R_EDX] = tswapl(scp->sc_edx);
365: env->regs[R_EDI] = tswapl(scp->sc_edi);
366: env->regs[R_ESI] = tswapl(scp->sc_esi);
367: env->regs[R_EBP] = tswapl(scp->sc_ebp);
368: env->regs[R_ESP] = tswapl(scp->sc_esp);
369: env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
370: env->eflags = tswapl(scp->sc_eflags);
371: env->eip = tswapl(scp->sc_eip);
372: env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
373: env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
374: env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
375: env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
376: env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);
377:
378: /* Again, because our caller's caller will reset EAX */
379: return env->regs[R_EAX];
380: }
381:
382: #else
383:
384: static void setup_frame(int sig, struct emulated_sigaction *ka,
385: void *set, CPUState *env)
386: {
387: fprintf(stderr, "setup_frame: not implemented\n");
388: }
389:
390: long do_sigreturn(CPUState *env, int num)
391: {
392: int i = 0;
393: struct target_sigcontext *scp = get_int_arg(&i, env);
394: fprintf(stderr, "do_sigreturn: not implemented\n");
395: return -ENOSYS;
396: }
397:
398: #endif
399:
400: void process_pending_signals(void *cpu_env)
401: {
402: struct emulated_sigaction *k;
403: struct sigqueue *q;
404: target_ulong handler;
405: int sig;
406:
407: if (!signal_pending)
408: return;
409:
410: k = sigact_table;
411:
412: for(sig = 1; sig <= NSIG; sig++) {
413: if (k->pending)
414: goto handle_signal;
415: k++;
416: }
417:
418: /* if no signal is pending, just return */
419: signal_pending = 0;
420: return;
421: handle_signal:
422: #ifdef DEBUG_SIGNAL
423: fprintf(stderr, "qemu: process signal %d\n", sig);
424: #endif
425: /* dequeue signal */
426: q = k->first;
427: k->first = q->next;
428: if (!k->first)
429: k->pending = 0;
430:
431: sig = gdb_handlesig (cpu_env, sig);
432: if (!sig) {
433: fprintf (stderr, "Lost signal\n");
434: abort();
435: }
436:
437: handler = k->sa.sa_handler;
438: if (handler == SIG_DFL) {
439: /* default handler : ignore some signal. The other are fatal */
440: if (sig != SIGCHLD &&
441: sig != SIGURG &&
442: sig != SIGWINCH) {
443: force_sig(sig);
444: }
445: } else if (handler == SIG_IGN) {
446: /* ignore sig */
447: } else if (handler == SIG_ERR) {
448: force_sig(sig);
449: } else {
450:
451: setup_frame(sig, k, 0, cpu_env);
452: if (k->sa.sa_flags & SA_RESETHAND)
453: k->sa.sa_handler = SIG_DFL;
454: }
455: if (q != &k->info)
456: free_sigqueue(q);
457: }
458:
459:
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