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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
1.1.1.3 ! root 18: * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
! 19: * MA 02110-1301, USA.
1.1 root 20: */
21: #include <stdlib.h>
22: #include <stdio.h>
23: #include <string.h>
24: #include <stdarg.h>
25: #include <unistd.h>
26: #include <signal.h>
27: #include <errno.h>
28: #include <sys/ucontext.h>
29:
30: #ifdef __ia64__
31: #undef uc_mcontext
32: #undef uc_sigmask
33: #undef uc_stack
34: #undef uc_link
35: #endif
36:
37: #include <signal.h>
38:
39: #include "qemu.h"
1.1.1.3 ! root 40: #include "qemu-common.h"
1.1 root 41:
42: #define DEBUG_SIGNAL
43:
44: #define MAX_SIGQUEUE_SIZE 1024
45:
46: struct sigqueue {
47: struct sigqueue *next;
48: target_siginfo_t info;
49: };
50:
51: struct emulated_sigaction {
52: struct target_sigaction sa;
53: int pending; /* true if signal is pending */
54: struct sigqueue *first;
55: struct sigqueue info; /* in order to always have memory for the
56: first signal, we put it here */
57: };
58:
1.1.1.3 ! root 59: static struct sigaltstack target_sigaltstack_used = {
1.1 root 60: 0, 0, SA_DISABLE
61: };
62:
63: static struct emulated_sigaction sigact_table[NSIG];
64: static struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
65: static struct sigqueue *first_free; /* first free siginfo queue entry */
66: static int signal_pending; /* non zero if a signal may be pending */
67:
68: static void host_signal_handler(int host_signum, siginfo_t *info,
69: void *puc);
70:
71:
72: static inline int host_to_target_signal(int sig)
73: {
74: return sig;
75: }
76:
77: static inline int target_to_host_signal(int sig)
78: {
79: return sig;
80: }
81:
82: /* siginfo conversion */
83:
84:
85:
86: void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info)
87: {
88:
89: }
90:
91: void target_to_host_siginfo(siginfo_t *info, const target_siginfo_t *tinfo)
92: {
93:
94: }
95:
96: void signal_init(void)
97: {
98: struct sigaction act;
99: int i;
100:
101: /* set all host signal handlers. ALL signals are blocked during
102: the handlers to serialize them. */
103: sigfillset(&act.sa_mask);
104: act.sa_flags = SA_SIGINFO;
105: act.sa_sigaction = host_signal_handler;
106: for(i = 1; i < NSIG; i++) {
107: sigaction(i, &act, NULL);
108: }
109:
110: memset(sigact_table, 0, sizeof(sigact_table));
111:
112: first_free = &sigqueue_table[0];
113: for(i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++)
114: sigqueue_table[i].next = &sigqueue_table[i + 1];
115: sigqueue_table[MAX_SIGQUEUE_SIZE - 1].next = NULL;
116: }
117:
118: /* signal queue handling */
119:
120: static inline struct sigqueue *alloc_sigqueue(void)
121: {
122: struct sigqueue *q = first_free;
123: if (!q)
124: return NULL;
125: first_free = q->next;
126: return q;
127: }
128:
129: static inline void free_sigqueue(struct sigqueue *q)
130: {
131: q->next = first_free;
132: first_free = q;
133: }
134:
135: /* abort execution with signal */
1.1.1.3 ! root 136: void QEMU_NORETURN force_sig(int sig)
1.1 root 137: {
138: int host_sig;
139: host_sig = target_to_host_signal(sig);
140: fprintf(stderr, "qemu: uncaught target signal %d (%s) - exiting\n",
141: sig, strsignal(host_sig));
142: _exit(-host_sig);
143: }
144:
145: /* queue a signal so that it will be send to the virtual CPU as soon
146: as possible */
147: int queue_signal(int sig, target_siginfo_t *info)
148: {
149: struct emulated_sigaction *k;
150: struct sigqueue *q, **pq;
151: target_ulong handler;
152:
153: #if defined(DEBUG_SIGNAL)
154: fprintf(stderr, "queue_signal: sig=%d\n",
155: sig);
156: #endif
157: k = &sigact_table[sig - 1];
158: handler = (target_ulong)k->sa.sa_handler;
159: if (handler == SIG_DFL) {
160: /* default handler : ignore some signal. The other are fatal */
161: if (sig != SIGCHLD &&
162: sig != SIGURG &&
163: sig != SIGWINCH) {
164: force_sig(sig);
165: } else {
166: return 0; /* indicate ignored */
167: }
168: } else if (handler == host_to_target_signal(SIG_IGN)) {
169: /* ignore signal */
170: return 0;
171: } else if (handler == host_to_target_signal(SIG_ERR)) {
172: force_sig(sig);
173: } else {
174: pq = &k->first;
175: if (!k->pending) {
176: /* first signal */
177: q = &k->info;
178: } else {
179: q = alloc_sigqueue();
180: if (!q)
181: return -EAGAIN;
182: while (*pq != NULL)
183: pq = &(*pq)->next;
184: }
185: *pq = q;
186: q->info = *info;
187: q->next = NULL;
188: k->pending = 1;
189: /* signal that a new signal is pending */
190: signal_pending = 1;
191: return 1; /* indicates that the signal was queued */
192: }
193: }
194:
195: static void host_signal_handler(int host_signum, siginfo_t *info,
196: void *puc)
197: {
198: int sig;
199: target_siginfo_t tinfo;
200:
201: /* the CPU emulator uses some host signals to detect exceptions,
202: we we forward to it some signals */
1.1.1.2 root 203: if (host_signum == SIGSEGV || host_signum == SIGBUS) {
1.1 root 204: if (cpu_signal_handler(host_signum, (void*)info, puc))
205: return;
206: }
207:
208: /* get target signal number */
209: sig = host_to_target_signal(host_signum);
210: if (sig < 1 || sig > NSIG)
211: return;
212:
213: #if defined(DEBUG_SIGNAL)
214: fprintf(stderr, "qemu: got signal %d\n", sig);
215: #endif
216: if (queue_signal(sig, &tinfo) == 1) {
217: /* interrupt the virtual CPU as soon as possible */
218: cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);
219: }
220: }
221:
222: int do_sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss)
223: {
224: /* XXX: test errors */
225: if(oss)
226: {
227: oss->ss_sp = tswap32(target_sigaltstack_used.ss_sp);
228: oss->ss_size = tswap32(target_sigaltstack_used.ss_size);
229: oss->ss_flags = tswap32(target_sigaltstack_used.ss_flags);
230: }
231: if(ss)
232: {
233: target_sigaltstack_used.ss_sp = tswap32(ss->ss_sp);
234: target_sigaltstack_used.ss_size = tswap32(ss->ss_size);
235: target_sigaltstack_used.ss_flags = tswap32(ss->ss_flags);
236: }
237: return 0;
238: }
239:
240: int do_sigaction(int sig, const struct sigaction *act,
241: struct sigaction *oact)
242: {
243: struct emulated_sigaction *k;
244: struct sigaction act1;
245: int host_sig;
246:
247: if (sig < 1 || sig > NSIG)
248: return -EINVAL;
249:
250: k = &sigact_table[sig - 1];
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: if (oact) {
256: #if defined(DEBUG_SIGNAL)
257: fprintf(stderr, "sigaction 1 sig=%d act=0x%08x, oact=0x%08x\n",
258: sig, (int)act, (int)oact);
259: #endif
260:
261: oact->sa_handler = tswapl(k->sa.sa_handler);
262: oact->sa_flags = tswapl(k->sa.sa_flags);
263: oact->sa_mask = tswapl(k->sa.sa_mask);
264: }
265: if (act) {
266: #if defined(DEBUG_SIGNAL)
267: fprintf(stderr, "sigaction handler 0x%x flag 0x%x mask 0x%x\n",
268: act->sa_handler, act->sa_flags, act->sa_mask);
269: #endif
270:
271: k->sa.sa_handler = tswapl(act->sa_handler);
272: k->sa.sa_flags = tswapl(act->sa_flags);
273: k->sa.sa_mask = tswapl(act->sa_mask);
274: /* we update the host signal state */
275: host_sig = target_to_host_signal(sig);
276: if (host_sig != SIGSEGV && host_sig != SIGBUS) {
277: #if defined(DEBUG_SIGNAL)
278: fprintf(stderr, "sigaction handler going to call sigaction\n",
279: act->sa_handler, act->sa_flags, act->sa_mask);
280: #endif
281:
282: sigfillset(&act1.sa_mask);
283: act1.sa_flags = SA_SIGINFO;
284: if (k->sa.sa_flags & SA_RESTART)
285: act1.sa_flags |= SA_RESTART;
286: /* NOTE: it is important to update the host kernel signal
287: ignore state to avoid getting unexpected interrupted
288: syscalls */
289: if (k->sa.sa_handler == SIG_IGN) {
290: act1.sa_sigaction = (void *)SIG_IGN;
291: } else if (k->sa.sa_handler == SIG_DFL) {
292: act1.sa_sigaction = (void *)SIG_DFL;
293: } else {
294: act1.sa_sigaction = host_signal_handler;
295: }
296: sigaction(host_sig, &act1, NULL);
297: }
298: }
299: return 0;
300: }
301:
302:
303: #ifdef TARGET_I386
304:
305: static inline void *
306: get_sigframe(struct emulated_sigaction *ka, CPUX86State *env, size_t frame_size)
307: {
308: /* XXX Fix that */
309: if(target_sigaltstack_used.ss_flags & SA_DISABLE)
310: {
311: int esp;
312: /* Default to using normal stack */
313: esp = env->regs[R_ESP];
314:
315: return (void *)((esp - frame_size) & -8ul);
316: }
317: else
318: {
319: return target_sigaltstack_used.ss_sp;
320: }
321: }
322:
323: static void setup_frame(int sig, struct emulated_sigaction *ka,
324: void *set, CPUState *env)
325: {
326: void *frame;
327: int i, err = 0;
328:
329: fprintf(stderr, "setup_frame %d\n", sig);
330: frame = get_sigframe(ka, env, sizeof(*frame));
331:
332: /* Set up registers for signal handler */
333: env->regs[R_ESP] = (unsigned long) frame;
334: env->eip = (unsigned long) ka->sa.sa_handler;
335:
336: env->eflags &= ~TF_MASK;
337:
338: return;
339:
340: give_sigsegv:
341: if (sig == SIGSEGV)
342: ka->sa.sa_handler = SIG_DFL;
343: force_sig(SIGSEGV /* , current */);
344: }
345:
346: long do_sigreturn(CPUState *env, int num)
347: {
348: int i = 0;
349: struct target_sigcontext *scp = get_int_arg(&i, env);
350: /* XXX Get current signal number */
351: /* XXX Adjust accordin to sc_onstack, sc_mask */
352: if(tswapl(scp->sc_onstack) & 0x1)
353: target_sigaltstack_used.ss_flags |= ~SA_DISABLE;
354: else
355: target_sigaltstack_used.ss_flags &= SA_DISABLE;
356: int set = tswapl(scp->sc_eax);
357: sigprocmask(SIG_SETMASK, &set, NULL);
358:
359: fprintf(stderr, "do_sigreturn: partially implemented %x EAX:%x EBX:%x\n", scp->sc_mask, tswapl(scp->sc_eax), tswapl(scp->sc_ebx));
360: fprintf(stderr, "ECX:%x EDX:%x EDI:%x\n", scp->sc_ecx, tswapl(scp->sc_edx), tswapl(scp->sc_edi));
361: fprintf(stderr, "EIP:%x\n", tswapl(scp->sc_eip));
362:
363: env->regs[R_EAX] = tswapl(scp->sc_eax);
364: env->regs[R_EBX] = tswapl(scp->sc_ebx);
365: env->regs[R_ECX] = tswapl(scp->sc_ecx);
366: env->regs[R_EDX] = tswapl(scp->sc_edx);
367: env->regs[R_EDI] = tswapl(scp->sc_edi);
368: env->regs[R_ESI] = tswapl(scp->sc_esi);
369: env->regs[R_EBP] = tswapl(scp->sc_ebp);
370: env->regs[R_ESP] = tswapl(scp->sc_esp);
371: env->segs[R_SS].selector = (void*)tswapl(scp->sc_ss);
372: env->eflags = tswapl(scp->sc_eflags);
373: env->eip = tswapl(scp->sc_eip);
374: env->segs[R_CS].selector = (void*)tswapl(scp->sc_cs);
375: env->segs[R_DS].selector = (void*)tswapl(scp->sc_ds);
376: env->segs[R_ES].selector = (void*)tswapl(scp->sc_es);
377: env->segs[R_FS].selector = (void*)tswapl(scp->sc_fs);
378: env->segs[R_GS].selector = (void*)tswapl(scp->sc_gs);
379:
380: /* Again, because our caller's caller will reset EAX */
381: return env->regs[R_EAX];
382: }
383:
384: #else
385:
386: static void setup_frame(int sig, struct emulated_sigaction *ka,
387: void *set, CPUState *env)
388: {
389: fprintf(stderr, "setup_frame: not implemented\n");
390: }
391:
392: long do_sigreturn(CPUState *env, int num)
393: {
394: int i = 0;
395: struct target_sigcontext *scp = get_int_arg(&i, env);
396: fprintf(stderr, "do_sigreturn: not implemented\n");
397: return -ENOSYS;
398: }
399:
400: #endif
401:
402: void process_pending_signals(void *cpu_env)
403: {
404: struct emulated_sigaction *k;
405: struct sigqueue *q;
406: target_ulong handler;
407: int sig;
408:
409: if (!signal_pending)
410: return;
411:
412: k = sigact_table;
413:
414: for(sig = 1; sig <= NSIG; sig++) {
415: if (k->pending)
416: goto handle_signal;
417: k++;
418: }
419:
420: /* if no signal is pending, just return */
421: signal_pending = 0;
422: return;
423: handle_signal:
424: #ifdef DEBUG_SIGNAL
425: fprintf(stderr, "qemu: process signal %d\n", sig);
426: #endif
427: /* dequeue signal */
428: q = k->first;
429: k->first = q->next;
430: if (!k->first)
431: k->pending = 0;
432:
433: sig = gdb_handlesig (cpu_env, sig);
434: if (!sig) {
435: fprintf (stderr, "Lost signal\n");
436: abort();
437: }
438:
439: handler = k->sa.sa_handler;
440: if (handler == SIG_DFL) {
441: /* default handler : ignore some signal. The other are fatal */
442: if (sig != SIGCHLD &&
443: sig != SIGURG &&
444: sig != SIGWINCH) {
445: force_sig(sig);
446: }
447: } else if (handler == SIG_IGN) {
448: /* ignore sig */
449: } else if (handler == SIG_ERR) {
450: force_sig(sig);
451: } else {
452:
453: setup_frame(sig, k, 0, cpu_env);
454: if (k->sa.sa_flags & SA_RESETHAND)
455: k->sa.sa_handler = SIG_DFL;
456: }
457: if (q != &k->info)
458: free_sigqueue(q);
459: }
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