/*
 * Wine signal handling
 *
 * Copyright 1995 Alexandre Julliard
 */

#include "config.h"

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <setjmp.h>

#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/types.h>
#include <sys/wait.h>

#ifdef HAVE_SYS_PARAM_H
# include <sys/param.h>
#endif
#ifdef HAVE_SYSCALL_H
# include <syscall.h>
#else
# ifdef HAVE_SYS_SYSCALL_H
#  include <sys/syscall.h>
# endif
#endif

#include "winsock.h"
#include "global.h"
#include "options.h"
#include "debugger.h"
#include "miscemu.h"
#include "dosexe.h"
#include "thread.h"
#include "debug.h"

void (*fnWINE_Debugger)(int,SIGCONTEXT*) = NULL;
void (*ctx_debug_call)(int sig,CONTEXT*ctx)=NULL;
BOOL (*fnINSTR_EmulateInstruction)(SIGCONTEXT*ctx)=NULL;


#ifdef __i386__

/* i386 specific faults */
static const char * const SIGNAL_traps[] =
{
    "Division by zero exception",      /* 0 */
    "Debug exception",                 /* 1 */
    "NMI interrupt",                   /* 2 */
    "Breakpoint exception",            /* 3 */
    "Overflow exception",              /* 4 */
    "Bound range exception",           /* 5 */
    "Invalid opcode exception",        /* 6 */
    "Device not available exception",  /* 7 */
    "Double fault exception",          /* 8 */
    "Coprocessor segment overrun",     /* 9 */
    "Invalid TSS exception",           /* 10 */
    "Segment not present exception",   /* 11 */
    "Stack fault",                     /* 12 */
    "General protection fault",        /* 13 */
    "Page fault",                      /* 14 */
    "Unknown exception",               /* 15 */
    "Floating point exception",        /* 16 */
    "Alignment check exception",       /* 17 */
    "Machine check exception"          /* 18 */
};
#define NB_TRAPS  (sizeof(SIGNAL_traps) / sizeof(SIGNAL_traps[0]))
#endif

/* Linux sigaction function */

#if defined(linux) && defined(__i386__)
/* This is the sigaction structure from the Linux 2.1.20 kernel.  */

#undef sa_handler
struct kernel_sigaction
{
    void (*sa_handler)();
    unsigned long sa_mask;
    unsigned long sa_flags;
    void (*sa_restorer)();
};

/* Similar to the sigaction function in libc, except it leaves alone the
   restorer field, which is used to specify the signal stack address */
static __inline__ int wine_sigaction( int sig, struct kernel_sigaction *new,
                                      struct kernel_sigaction *old )
{
#ifdef __PIC__
    __asm__ __volatile__( "pushl %%ebx\n\t"
                          "movl %2,%%ebx\n\t"
                          "int $0x80\n\t"
                          "popl %%ebx"
                          : "=a" (sig)
                          : "0" (SYS_sigaction),
                            "r" (sig),
                            "c" (new),
                            "d" (old) );
#else
    __asm__ __volatile__( "int $0x80"
                          : "=a" (sig)
                          : "0" (SYS_sigaction),
                            "b" (sig),
                            "c" (new),
                            "d" (old) );
#endif  /* __PIC__ */
    if (sig>=0)
        return 0;
    errno = -sig;
    return -1;
}
#endif /* linux && __i386__ */

/* Signal stack */

static char SIGNAL_Stack[16384];
static sigset_t async_signal_set;

/**********************************************************************
 *              SIGNAL_child
 * 
 * wait4 terminated child processes
 */
static HANDLER_DEF(SIGNAL_child)
{
    HANDLER_INIT();
#ifdef HAVE_WAIT4
    wait4( 0, NULL, WNOHANG, NULL);
#elif defined (HAVE_WAITPID)
    /* I am sort-of guessing that this is the same as the wait4 call.  */
    waitpid (0, NULL, WNOHANG);
#else
    wait(NULL);
#endif
}


/**********************************************************************
 *		SIGNAL_SetHandler
 */
void SIGNAL_SetHandler( int sig, void (*func)(), int flags )
{
    int ret;

#if defined(linux) && defined(__i386__)

    struct kernel_sigaction sig_act;
    sig_act.sa_handler = func;
    sig_act.sa_flags   = SA_RESTART | (flags) ? SA_NOMASK : 0;
    sig_act.sa_mask    = 0;
    /* Point to the top of the stack, minus 4 just in case, and make
       it aligned  */
    sig_act.sa_restorer = 
        (void (*)())((int)(SIGNAL_Stack + sizeof(SIGNAL_Stack) - 4) & ~3);
    ret = wine_sigaction( sig, &sig_act, NULL );

#else  /* linux && __i386__ */

    struct sigaction sig_act;
    sig_act.sa_handler = func;
    sigemptyset( &sig_act.sa_mask );

# if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
    sig_act.sa_flags = SA_ONSTACK;
# elif defined (__svr4__) || defined(_SCO_DS)
    sig_act.sa_flags = SA_SIGINFO | SA_ONSTACK | SA_RESTART;
# elif defined(__EMX__)
    sig_act.sa_flags = 0; /* FIXME: EMX has only SA_ACK and SA_SYSV */
# else
    sig_act.sa_flags = 0;
# endif
    ret = sigaction( sig, &sig_act, NULL );

#endif  /* linux && __i386__ */

    if (ret < 0)
    {
        perror( "sigaction" );
        exit(1);
    }
}

extern void stop_wait(int a);
extern void WINSOCK_sigio(int a);
extern void ASYNC_sigio(int a);


/**********************************************************************
 *              SIGNAL_MaskAsyncEvents
 */
void SIGNAL_MaskAsyncEvents( BOOL flag )
{
  sigprocmask( (flag) ? SIG_BLOCK : SIG_UNBLOCK , &async_signal_set, NULL);
}

extern void SIGNAL_SetHandler( int sig, void (*func)(), int flags );

/**********************************************************************
 *              SIGNAL_break
 * 
 * Handle Ctrl-C and such
 */
static HANDLER_DEF(SIGNAL_break)
{
    HANDLER_INIT();
    if (Options.debug && fnWINE_Debugger)
        fnWINE_Debugger( signal, HANDLER_CONTEXT );  /* Enter our debugger */
    else exit(0);
}


/**********************************************************************
 *		SIGNAL_trap
 *
 * SIGTRAP handler.
 */
static HANDLER_DEF(SIGNAL_trap)
{
    HANDLER_INIT();
    if (fnWINE_Debugger)
	fnWINE_Debugger( signal, HANDLER_CONTEXT );  /* Enter our debugger */
}


/**********************************************************************
 *		SIGNAL_fault
 *
 * Segfault handler.
 */
static HANDLER_DEF(SIGNAL_fault)
{
    const char *fault = "Segmentation fault";
    HANDLER_INIT();

#ifdef __i386__

#if defined(TRAP_sig) && defined(CR2_sig)
    if (TRAP_sig(HANDLER_CONTEXT) == 0x0e
        && VIRTUAL_HandleFault( (LPVOID)CR2_sig(HANDLER_CONTEXT) ))
	return;
#endif
#if defined(TRAP_sig)
   /* We don't do alignment checks */
   /* FIXME: if we get SEHs, pass the fault through them first? */
   if (TRAP_sig(HANDLER_CONTEXT) == 0x11) {
   	if (EFL_sig(HANDLER_CONTEXT) & 0x00040000) {
		/* Disable AC flag, return */
		EFL_sig(HANDLER_CONTEXT) &= ~0x00040000;
		return;
	}
   }
#endif

    if (fnINSTR_EmulateInstruction && 
	fnINSTR_EmulateInstruction( HANDLER_CONTEXT )
    )
	return;

#ifdef TRAP_sig
    if (TRAP_sig( HANDLER_CONTEXT ) < NB_TRAPS)
        fault = SIGNAL_traps[TRAP_sig( HANDLER_CONTEXT )];
#endif
    if (IS_SELECTOR_SYSTEM(CS_sig(HANDLER_CONTEXT)))
    {
        MSG("%s in 32-bit code (0x%08lx).\n", fault, EIP_sig(HANDLER_CONTEXT));
    }
    else
    {
        MSG("%s in 16-bit code (%04x:%04lx).\n", fault,
            (WORD)CS_sig(HANDLER_CONTEXT), EIP_sig(HANDLER_CONTEXT) );
    }
#ifdef CR2_sig
    MSG("Fault address is 0x%08lx\n",CR2_sig(HANDLER_CONTEXT));
#endif
#endif

    if (fnWINE_Debugger)
	fnWINE_Debugger( signal, HANDLER_CONTEXT );
    else {
    	MSG("stopping pid %d due to unhandled %s.\n",getpid(),fault);
	kill(getpid(),SIGSTOP);
    }
}


/**********************************************************************
 *		SIGNAL_InitHandlers
 */
void SIGNAL_InitHandlers(void)
{
    SIGNAL_SetHandler( SIGINT,  (void (*)())SIGNAL_break, 1);
    SIGNAL_SetHandler( SIGSEGV, (void (*)())SIGNAL_fault, 1);
    SIGNAL_SetHandler( SIGILL,  (void (*)())SIGNAL_fault, 1);
    SIGNAL_SetHandler( SIGFPE,  (void (*)())SIGNAL_fault, 1);
    SIGNAL_SetHandler( SIGTRAP, (void (*)())SIGNAL_trap,  1); /* debugger */
    SIGNAL_SetHandler( SIGHUP,  (void (*)())SIGNAL_trap,  1); /* forced break*/
#ifdef SIGBUS
    SIGNAL_SetHandler( SIGBUS,  (void (*)())SIGNAL_fault, 1);
#endif
    return;
}

/**********************************************************************
 *		SIGNAL_Init
 */
BOOL SIGNAL_Init(void)
{
#ifdef HAVE_WORKING_SIGALTSTACK
    struct sigaltstack ss;
    ss.ss_sp    = SIGNAL_Stack;
    ss.ss_size  = sizeof(SIGNAL_Stack);
    ss.ss_flags = 0;
    if (sigaltstack(&ss, NULL) < 0)
    {
        perror("sigaltstack");
        return FALSE;
    }
#endif  /* HAVE_SIGALTSTACK */
    
    sigemptyset(&async_signal_set);

    SIGNAL_SetHandler( SIGCHLD, (void (*)())SIGNAL_child, 1);
#ifdef CONFIG_IPC
    sigaddset(&async_signal_set, SIGUSR2);
    SIGNAL_SetHandler( SIGUSR2, (void (*)())stop_wait, 1); 	/* For IPC */
#endif
#ifdef SIGIO
    sigaddset(&async_signal_set, SIGIO);
/*    SIGNAL_SetHandler( SIGIO,   (void (*)())WINSOCK_sigio, 0);  */
    SIGNAL_SetHandler( SIGIO,   (void (*)())ASYNC_sigio, 0); 
#endif
    sigaddset(&async_signal_set, SIGALRM);

    /* ignore SIGPIPE so that WINSOCK can get a EPIPE error instead  */
    signal (SIGPIPE, SIG_IGN);
    SIGNAL_InitHandlers();
    return TRUE;
}