Source code of Windows XP (NT5)
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/***
*winsig.c - C signal support
*
* Copyright (c) 1991-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines signal(), raise() and supporting functions.
*
*Revision History:
* 10-21-91 GJF Signal for Win32 and Dosx32. Copied from old signal.c
* (the Cruiser implementation with some revisions for
* Win32), then extensively rewritten.
* 11-08-91 GJF Cleaned up header files usage.
* 12-13-91 GJF Fixed multi-thread build.
* 09-30-92 SRW Add WINAPI keyword to CtrlC handler
* 02-17-93 GJF Changed for new _getptd().
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 07-29-93 GJF Must reset the action for all FPE-s to SIG_DFL when
* SIGFPE is raised.
* 09-06-94 CFW Replace MTHREAD with _MT.
* 01-10-95 CFW Debug CRT allocs.
* 08-16-96 GJF Fixed overruns of _XctActTab. Also, detab-ed.
* 08-21-96 GJF Fixed _MT part of overrun fix.
* 03-05-98 GJF Exception-safe locking.
*
*******************************************************************************/
#ifndef _POSIX_
#include <cruntime.h>
#include <errno.h>
#include <float.h>
#include <malloc.h>
#include <mtdll.h>
#include <oscalls.h>
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <dbgint.h>
/*
* look up the first entry in the exception-action table corresponding to
* the given signal
*/
#ifdef _MT
static struct _XCPT_ACTION * __cdecl siglookup(int, struct _XCPT_ACTION *);
#else /* not _MT */
static struct _XCPT_ACTION * __cdecl siglookup(int);
#endif /* _MT */
/*
* variables holding action codes (and code pointers) for SIGINT, SIGBRK,
* SIGABRT and SIGTERM.
*
* note that the disposition (i.e., action to be taken upon receipt) of
* these signals is defined on a per-process basis (not per-thread)!!
*/
static _PHNDLR ctrlc_action = SIG_DFL; /* SIGINT */
static _PHNDLR ctrlbreak_action = SIG_DFL; /* SIGBREAK */
static _PHNDLR abort_action = SIG_DFL; /* SIGABRT */
static _PHNDLR term_action = SIG_DFL; /* SIGTERM */
/*
* flag indicated whether or not a handler has been installed to capture
* ^C and ^Break events.
*/
static int ConsoleCtrlHandler_Installed = 0;
/***
*static BOOL WINAPI ctrlevent_capture(DWORD CtrlType) - capture ^C and ^Break events
*
*Purpose:
* Capture ^C and ^Break events from the console and dispose of them
* according the values in ctrlc_action and ctrlbreak_action, resp.
* This is the routine that evokes the user-defined action for SIGINT
* (^C) or SIGBREAK (^Break) installed by a call to signal().
*
*Entry:
* DWORD CtrlType - indicates type of event, two values:
* CTRL_C_EVENT
* CTRL_BREAK_EVENT
*
*Exit:
* Returns TRUE to indicate the event (signal) has been handled.
* Otherwise, returns FALSE.
*
*Exceptions:
*
*******************************************************************************/
static BOOL WINAPI ctrlevent_capture (
DWORD CtrlType
)
{
_PHNDLR ctrl_action;
_PHNDLR *pctrl_action;
int sigcode;
#ifdef _MT
_mlock(_SIGNAL_LOCK);
__try {
#endif /* _MT */
/*
* Identify the type of event and fetch the corresponding action
* description.
*/
if ( CtrlType == CTRL_C_EVENT ) {
ctrl_action = *(pctrl_action = &ctrlc_action);
sigcode = SIGINT;
}
else {
ctrl_action = *(pctrl_action = &ctrlbreak_action);
sigcode = SIGBREAK;
}
#ifdef _MT
if ( !(ctrl_action == SIG_DFL) && !(ctrl_action == SIG_IGN) )
/*
* Reset the action to be SIG_DFL
*/
*pctrl_action = SIG_DFL;
}
__finally {
_munlock(_SIGNAL_LOCK);
}
#endif /* _MT */
if ( ctrl_action == SIG_DFL )
/*
* return FALSE, indicating the event has NOT been handled
*/
return FALSE;
if ( ctrl_action != SIG_IGN ) {
#ifndef _MT
/*
* Reset the action to be SIG_DFL and call the user's handler.
*/
*pctrl_action = SIG_DFL;
#endif /* ndef _MT */
(*ctrl_action)(sigcode);
}
/*
* Return TRUE, indicating the event has been handled (which may
* mean it's being ignored)
*/
return TRUE;
}
/***
*_PHNDLR signal(signum, sigact) - Define a signal handler
*
*Purpose:
* The signal routine allows the user to define what action should
* be taken when various signals occur. The Win32/Dosx32 implementation
* supports seven signals, divided up into three general groups
*
* 1. Signals corresponding to OS exceptions. These are:
* SIGFPE
* SIGILL
* SIGSEGV
* Signal actions for these signals are installed by altering the
* XcptAction and SigAction fields for the appropriate entry in the
* exception-action table (XcptActTab[]).
*
* 2. Signals corresponding to ^C and ^Break. These are:
* SIGINT
* SIGBREAK
* Signal actions for these signals are installed by altering the
* _ctrlc_action and _ctrlbreak_action variables.
*
* 3. Signals which are implemented only in the runtime. That is, they
* occur only as the result of a call to raise().
* SIGABRT
* SIGTERM
*
*
*Entry:
* int signum signal type. recognized signal types are:
*
* SIGABRT (ANSI)
* SIGBREAK
* SIGFPE (ANSI)
* SIGILL (ANSI)
* SIGINT (ANSI)
* SIGSEGV (ANSI)
* SIGTERM (ANSI)
*
* _PHNDLR sigact signal handling function or action code. the action
* codes are:
*
* SIG_DFL - take the default action, whatever that may
* be, upon receipt of this type type of signal.
*
* SIG_DIE - *** ILLEGAL ***
* special code used in the XcptAction field of an
* XcptActTab[] entry to indicate that the runtime is
* to terminate the process upon receipt of the exception.
* not accepted as a value for sigact.
*
* SIG_IGN - ignore this type of signal
*
* [function address] - transfer control to this address
* when a signal of this type occurs.
*
*Exit:
* Good return:
* Signal returns the previous value of the signal handling function
* (e.g., SIG_DFL, SIG_IGN, etc., or [function address]). This value is
* returned in DX:AX.
*
* Error return:
* Signal returns -1 and errno is set to EINVAL. The error return is
* generally taken if the user submits bogus input values.
*
*Exceptions:
* None.
*
*******************************************************************************/
_PHNDLR __cdecl signal(
int signum,
_PHNDLR sigact
)
{
struct _XCPT_ACTION *pxcptact;
_PHNDLR oldsigact;
#ifdef _MT
_ptiddata ptd;
#endif
/*
* Check for values of sigact supported on other platforms but not
* on this one. Also, make sure sigact is not SIG_DIE
*/
if ( (sigact == SIG_ACK) || (sigact == SIG_SGE) )
goto sigreterror;
/*
* Take care of all signals which do not correspond to exceptions
* in the host OS. Those are:
*
* SIGINT
* SIGBREAK
* SIGABRT
* SIGTERM
*
*/
if ( (signum == SIGINT) || (signum == SIGBREAK) || (signum == SIGABRT)
|| (signum == SIGTERM) ) {
#ifdef _MT
_mlock( _SIGNAL_LOCK );
__try {
#endif
/*
* if SIGINT or SIGBREAK, make sure the handler is installed
* to capture ^C and ^Break events.
*/
if ( ((signum == SIGINT) || (signum == SIGBREAK)) &&
!ConsoleCtrlHandler_Installed )
if ( SetConsoleCtrlHandler(ctrlevent_capture, TRUE)
== TRUE )
ConsoleCtrlHandler_Installed = TRUE;
else {
_doserrno = GetLastError();
_munlock(_SIGNAL_LOCK);
goto sigreterror;
}
switch (signum) {
case SIGINT:
oldsigact = ctrlc_action;
ctrlc_action = sigact;
break;
case SIGBREAK:
oldsigact = ctrlbreak_action;
ctrlbreak_action = sigact;
break;
case SIGABRT:
oldsigact = abort_action;
abort_action = sigact;
break;
case SIGTERM:
oldsigact = term_action;
term_action = sigact;
break;
}
#ifdef _MT
}
__finally {
_munlock( _SIGNAL_LOCK );
}
#endif
goto sigretok;
}
/*
* If we reach here, signum is supposed to be one the signals which
* correspond to exceptions in the host OS. Those are:
*
* SIGFPE
* SIGILL
* SIGSEGV
*/
/*
* Make sure signum is one of the remaining supported signals.
*/
if ( (signum != SIGFPE) && (signum != SIGILL) && (signum != SIGSEGV) )
goto sigreterror;
#ifdef _MT
/*
* Fetch the tid data table entry for this thread
*/
ptd = _getptd();
/*
* Check that there a per-thread instance of the exception-action
* table for this thread. if there isn't, create one.
*/
if ( ptd->_pxcptacttab == _XcptActTab )
/*
* allocate space for an exception-action table
*/
if ( (ptd->_pxcptacttab = _malloc_crt(_XcptActTabSize)) != NULL )
/*
* initialize the table by copying over the contents
* of _XcptActTab[]
*/
(void) memcpy(ptd->_pxcptacttab, _XcptActTab,
_XcptActTabSize);
else
/*
* cannot create exception-action table, return
* error to caller
*/
goto sigreterror;
#endif /* _MT */
/*
* look up the proper entry in the exception-action table. note that
* if several exceptions are mapped to the same signal, this returns
* the pointer to first such entry in the exception action table. it
* is assumed that the other entries immediately follow this one.
*/
#ifdef _MT
if ( (pxcptact = siglookup(signum, ptd->_pxcptacttab)) == NULL )
#else /* not _MT */
if ( (pxcptact = siglookup(signum)) == NULL )
#endif /* _MT */
goto sigreterror;
/*
* SIGSEGV, SIGILL and SIGFPE all have more than one exception mapped
* to them. the code below depends on the exceptions corresponding to
* the same signal being grouped together in the exception-action
* table.
*/
/*
* store old signal action code for return value
*/
oldsigact = pxcptact->XcptAction;
/*
* loop through all entries corresponding to the
* given signal and update the SigAction and XcptAction
* fields as appropriate
*/
while ( pxcptact->SigNum == signum ) {
/*
* take care of the SIG_IGN and SIG_DFL action
* codes
*/
pxcptact->XcptAction = sigact;
/*
* make sure we don't run off the end of the table
*/
#ifdef _MT
if ( ++pxcptact >= ((struct _XCPT_ACTION *)(ptd->_pxcptacttab)
+ _XcptActTabCount) )
#else /* not _MT */
if ( ++pxcptact >= (_XcptActTab + _XcptActTabCount) )
#endif /* _MT */
break;
}
sigretok:
return(oldsigact);
sigreterror:
errno = EINVAL;
return(SIG_ERR);
}
/***
*int raise(signum) - Raise a signal
*
*Purpose:
* This routine raises a signal (i.e., performs the action currently
* defined for this signal). The action associated with the signal is
* evoked directly without going through intermediate dispatching or
* handling.
*
*Entry:
* int signum - signal type (e.g., SIGINT)
*
*Exit:
* returns 0 on good return, -1 on bad return.
*
*Exceptions:
* May not return. Raise has no control over the action
* routines defined for the various signals. Those routines may
* abort, terminate, etc. In particular, the default actions for
* certain signals will terminate the program.
*
*******************************************************************************/
int __cdecl raise (
int signum
)
{
_PHNDLR sigact;
_PHNDLR *psigact;
PEXCEPTION_POINTERS oldpxcptinfoptrs;
int oldfpecode;
int indx;
#ifdef _MT
int siglock = 0;
_ptiddata ptd;
#endif
switch (signum) {
case SIGINT:
sigact = *(psigact = &ctrlc_action);
#ifdef _MT
siglock++;
#endif
break;
case SIGBREAK:
sigact = *(psigact = &ctrlbreak_action);
#ifdef _MT
siglock++;
#endif
break;
case SIGABRT:
sigact = *(psigact = &abort_action);
#ifdef _MT
siglock++;
#endif
break;
case SIGTERM:
sigact = *(psigact = &term_action);
#ifdef _MT
siglock++;
#endif
break;
case SIGFPE:
case SIGILL:
case SIGSEGV:
#ifdef _MT
ptd = _getptd();
sigact = *(psigact = &(siglookup( signum,
ptd->_pxcptacttab )->XcptAction));
#else
sigact = *(psigact = &(siglookup( signum )->
XcptAction));
#endif
break;
default:
/*
* unsupported signal, return an error
*/
return (-1);
}
/*
* If the current action is SIG_IGN, just return
*/
if ( sigact == SIG_IGN )
return(0);
/*
* If the current action is SIG_DFL, take the default action
*/
if ( sigact == SIG_DFL ) {
/*
* The current default action for all of the supported
* signals is to terminate with an exit code of 3.
*/
_exit(3);
}
#ifdef _MT
/*
* if signum is one of the 'process-wide' signals (i.e., SIGINT,
* SIGBREAK, SIGABRT or SIGTERM), assert _SIGNAL_LOCK.
*/
if ( siglock )
_mlock(_SIGNAL_LOCK);
__try {
#endif
/*
* From here on, sigact is assumed to be a pointer to a user-supplied
* handler.
*/
/*
* For signals which correspond to exceptions, set the pointer
* to the EXCEPTION_POINTERS structure to NULL
*/
if ( (signum == SIGFPE) || (signum == SIGSEGV) ||
(signum == SIGILL) ) {
#ifdef _MT
oldpxcptinfoptrs = ptd->_tpxcptinfoptrs;
ptd->_tpxcptinfoptrs = NULL;
#else
oldpxcptinfoptrs = _pxcptinfoptrs;
_pxcptinfoptrs = NULL;
#endif
/*
* If signum is SIGFPE, also set _fpecode to
* _FPE_EXPLICITGEN
*/
if ( signum == SIGFPE ) {
#ifdef _MT
oldfpecode = ptd->_tfpecode;
ptd->_tfpecode = _FPE_EXPLICITGEN;
#else
oldfpecode = _fpecode;
_fpecode = _FPE_EXPLICITGEN;
#endif
}
}
/*
* Reset the action to SIG_DFL and call the user specified handler
* routine.
*/
if ( signum == SIGFPE )
/*
* for SIGFPE, must reset the action for all of the floating
* point exceptions
*/
for ( indx = _First_FPE_Indx ;
indx < _First_FPE_Indx + _Num_FPE ;
indx++ )
{
#ifdef _MT
( (struct _XCPT_ACTION *)(ptd->_pxcptacttab) +
indx )->XcptAction = SIG_DFL;
#else
_XcptActTab[indx].XcptAction = SIG_DFL;
#endif
}
else
*psigact = SIG_DFL;
#ifdef _MT
}
__finally {
if ( siglock )
_munlock(_SIGNAL_LOCK);
}
#endif
if ( signum == SIGFPE )
/*
* Special code to support old SIGFPE handlers which
* expect the value of _fpecode as the second argument.
*/
#ifdef _MT
(*(void (__cdecl *)(int,int))sigact)(SIGFPE,
ptd->_tfpecode);
#else
(*(void (__cdecl *)(int,int))sigact)(SIGFPE, _fpecode);
#endif
else
(*sigact)(signum);
/*
* For signals which correspond to exceptions, restore the pointer
* to the EXCEPTION_POINTERS structure.
*/
if ( (signum == SIGFPE) || (signum == SIGSEGV) ||
(signum == SIGILL) ) {
#ifdef _MT
ptd->_tpxcptinfoptrs = oldpxcptinfoptrs;
#else
_pxcptinfoptrs = oldpxcptinfoptrs;
#endif
/*
* If signum is SIGFPE, also restore _fpecode
*/
if ( signum == SIGFPE )
#ifdef _MT
ptd->_tfpecode = oldfpecode;
#else
_fpecode = oldfpecode;
#endif
}
return(0);
}
/***
*struct _XCPT_ACTION *siglookup(int signum) - look up exception-action table
* entry for signal.
*
*Purpose:
* Find the first entry int _XcptActTab[] whose SigNum field is signum.
*
*Entry:
* int signum - C signal type (e.g., SIGINT)
*
*Exit:
* If successful, pointer to the table entry. If no such entry, NULL is
* returned.
*
*Exceptions:
*
*******************************************************************************/
#ifdef _MT
static struct _XCPT_ACTION * __cdecl siglookup (
int signum,
struct _XCPT_ACTION *pxcptacttab
)
{
struct _XCPT_ACTION *pxcptact = pxcptacttab;
#else /* not _MT */
static struct _XCPT_ACTION * __cdecl siglookup(int signum)
{
struct _XCPT_ACTION *pxcptact = _XcptActTab;
#endif /* _MT */
/*
* walk thru the _xcptactab table looking for the proper entry. note
* that in the case where more than one exception corresponds to the
* same signal, the first such instance in the table is the one
* returned.
*/
#ifdef _MT
while ( (pxcptact->SigNum != signum) &&
(++pxcptact < pxcptacttab + _XcptActTabCount) ) ;
#else /* not _MT */
while ( (pxcptact->SigNum != signum) &&
(++pxcptact < _XcptActTab + _XcptActTabCount) ) ;
#endif /* _MT */
#ifdef _MT
if ( (pxcptact < (pxcptacttab + _XcptActTabCount)) &&
#else /* not _MT */
if ( (pxcptact < (_XcptActTab + _XcptActTabCount)) &&
#endif /* _MT */
(pxcptact->SigNum == signum) )
/*
* found a table entry corresponding to the signal
*/
return(pxcptact);
else
/*
* found no table entry corresponding to the signal
*/
return(NULL);
}
#ifdef _MT
/***
*int *__fpecode(void) - return pointer to _fpecode field of the tidtable entry
* for the current thread
*
*Purpose:
*
*Entry:
*
*Exit:
*
*Exceptions:
*
*******************************************************************************/
int * __cdecl __fpecode (
void
)
{
return( &(_getptd()->_tfpecode) );
}
/***
*void **__pxcptinfoptrs(void) - return pointer to _pxcptinfoptrs field of the
* tidtable entry for the current thread
*
*Purpose:
*
*Entry:
*
*Exit:
*
*Exceptions:
*
*******************************************************************************/
void ** __cdecl __pxcptinfoptrs (
void
)
{
return( &(_getptd()->_tpxcptinfoptrs) );
}
#endif
#endif /* _POSIX_ */