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Annotation of qemu/darwin-user/signal.c, revision 1.1

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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