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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
1.1.1.4 root 17: * along with this program; if not, see <http://www.gnu.org/licenses/>.
1.1 root 18: */
19: #include <stdlib.h>
20: #include <stdio.h>
21: #include <string.h>
22: #include <stdarg.h>
23: #include <unistd.h>
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:
34: #include "qemu.h"
1.1.1.3 root 35: #include "qemu-common.h"
1.1 root 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:
1.1.1.3 root 54: static struct sigaltstack target_sigaltstack_used = {
1.1 root 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 */
1.1.1.3 root 131: void QEMU_NORETURN force_sig(int sig)
1.1 root 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 */
1.1.1.2 root 198: if (host_signum == SIGSEGV || host_signum == SIGBUS) {
1.1 root 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 */
1.1.1.4 root 213: cpu_exit(global_env);
1.1 root 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;
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: }
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