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ACE_Sig_Handler Class Reference

This is the main dispatcher of signals for ACE. It improves the existing UNIX signal handling mechanism by allowing C++ objects to handle signals in a way that avoids the use of global/static variables and functions. More...

#include <Sig_Handler.h>

Inheritance diagram for ACE_Sig_Handler:

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Collaboration diagram for ACE_Sig_Handler:

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List of all members.

Public Member Functions

 ACE_Sig_Handler (void)
 Default ctor/dtor.

virtual ~ACE_Sig_Handler (void)
virtual int register_handler (int signum, ACE_Event_Handler *new_sh, ACE_Sig_Action *new_disp=0, ACE_Event_Handler **old_sh=0, ACE_Sig_Action *old_disp=0)
virtual int remove_handler (int signum, ACE_Sig_Action *new_disp=0, ACE_Sig_Action *old_disp=0, int sigkey=-1)
virtual ACE_Event_Handler * handler (int signum)
 Return the associated with signum.

virtual ACE_Event_Handler * handler (int signum, ACE_Event_Handler *)
void dump (void) const
 Dump the state of an object.


Static Public Member Functions

int sig_pending (void)
 True if there is a pending signal.

void sig_pending (int)
 Reset the value of so that no signal is pending.

void dispatch (int, siginfo_t *, ucontext_t *)

Public Attributes

 ACE_ALLOC_HOOK_DECLARE
 Declare the dynamic allocation hooks.


Static Protected Member Functions

ACE_Event_Handler * handler_i (int signum, ACE_Event_Handler *)
int register_handler_i (int signum, ACE_Event_Handler *new_sh, ACE_Sig_Action *new_disp=0, ACE_Event_Handler **old_sh=0, ACE_Sig_Action *old_disp=0)
int in_range (int signum)
 Check whether the SIGNUM is within the legal range of signals.


Static Protected Attributes

sig_atomic_t sig_pending_ = 0
 Keeps track of whether a signal is pending.


Static Private Attributes

ACE_Event_Handler * signal_handlers_ [ACE_NSIG]

Detailed Description

This is the main dispatcher of signals for ACE. It improves the existing UNIX signal handling mechanism by allowing C++ objects to handle signals in a way that avoids the use of global/static variables and functions.

Using this class a program can register an ACE_Event_Handler with the ACE_Sig_Handler in order to handle a designated signum. When a signal occurs that corresponds to this signum, the handle_signal method of the registered ACE_Event_Handler is invoked automatically.

Definition at line 43 of file Sig_Handler.h.

Constructor & Destructor Documentation

ACE_INLINE ACE_Sig_Handler::ACE_Sig_Handler (  void   ) 
 

Default ctor/dtor.

Definition at line 6 of file Sig_Handler.inl. 

00007 {
00008 }

ACE_Sig_Handler::~ACE_Sig_Handler (  void   )  [virtual]
 

Definition at line 59 of file Sig_Handler.cpp. 

00060 {
00061 }

Member Function Documentation

void ACE_Sig_Handler::dispatch (  int  ,
siginfo_t *  ,
ucontext_t * 
)  [static]
 

Callback routine registered with sigaction(2) that dispatches the method of the appropriate pre-registered ACE_Event_Handler.

Reimplemented in ACE_Sig_Handlers.

Definition at line 236 of file Sig_Handler.cpp.

References ACE_ASSERT, ACE_SignalHandler, ACE_TRACE, ACE_Event_Handler::handle_close(), ACE_Event_Handler::handle_signal(), in_range(), ACE_Sig_Action::register_action(), register_handler_i(), SIG_DFL, sig_pending_, signal_handlers_, and ucontext_t. 

00239 {
00240   ACE_TRACE ("ACE_Sig_Handler::dispatch");
00241 
00242   // Save/restore errno.
00243   ACE_Errno_Guard error (errno);
00244 
00245   // We can't use the <sig_pending> call here because that acquires
00246   // the lock, which is non-portable...
00247   ACE_Sig_Handler::sig_pending_ = 1;
00248 
00249   // Darn well better be in range since the OS dispatched this...
00250   ACE_ASSERT (ACE_Sig_Handler::in_range (signum));
00251 
00252   ACE_Event_Handler *eh = ACE_Sig_Handler::signal_handlers_[signum];
00253 
00254   if (eh != 0)
00255     {
00256       if (eh->handle_signal (signum, siginfo, ucontext) == -1)
00257         {
00258           // Define the default disposition.
00259           ACE_Sig_Action sa ((ACE_SignalHandler) SIG_DFL, (sigset_t *) 0);
00260 
00261           ACE_Sig_Handler::signal_handlers_[signum] = 0;
00262 
00263           // Remove the current disposition by registering the default
00264           // disposition.
00265           sa.register_action (signum);
00266 
00267           // Allow the event handler to close down if necessary.
00268           eh->handle_close (ACE_INVALID_HANDLE,
00269                             ACE_Event_Handler::SIGNAL_MASK);
00270         }
00271 #if defined (ACE_WIN32)
00272       else
00273         // Win32 is weird in the sense that it resets the signal
00274         // disposition to SIG_DFL after a signal handler is
00275         // dispatched.  Therefore, to workaround this "feature" we
00276         // must re-register the <ACE_Event_Handler> with <signum>
00277         // explicitly.
00278         ACE_Sig_Handler::register_handler_i (signum,
00279                                              eh);
00280 #endif /* ACE_WIN32*/
00281     }
00282 }

void ACE_Sig_Handler::dump (  void   )  const
 

Dump the state of an object.

Reimplemented in ACE_Sig_Handlers.

Definition at line 64 of file Sig_Handler.cpp.

References ACE_TRACE.

Referenced by ACE_Select_Reactor_T< ACE_SELECT_REACTOR_TOKEN >::dump(). 

00065 {
00066 #if defined (ACE_HAS_DUMP)
00067   ACE_TRACE ("ACE_Sig_Handler::dump");
00068 #endif /* ACE_HAS_DUMP */
00069 }

ACE_Event_Handler * ACE_Sig_Handler::handler (  int  signum,
ACE_Event_Handler * 
)  [virtual]
 

Set a new ACE_Event_Handler that is associated with signum. Return the existing handler.

Reimplemented in ACE_Sig_Handlers.

Definition at line 127 of file Sig_Handler.cpp.

References ACE_TRACE, and handler_i(). 

00129 {
00130   ACE_TRACE ("ACE_Sig_Handler::handler");
00131   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00132     ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00133       (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00134     ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00135 
00136   return ACE_Sig_Handler::handler_i (signum, new_sh);
00137 }

ACE_Event_Handler * ACE_Sig_Handler::handler (  int  signum  )  [virtual]
 

Return the associated with signum.

Reimplemented in ACE_Sig_Handlers.

Definition at line 95 of file Sig_Handler.cpp.

References ACE_TRACE, in_range(), and signal_handlers_.

Referenced by ACE_Select_Reactor_T< ACE_SELECT_REACTOR_TOKEN >::handler_i(). 

00096 {
00097   ACE_TRACE ("ACE_Sig_Handler::handler");
00098   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00099     ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00100       (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00101     ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00102 
00103   if (ACE_Sig_Handler::in_range (signum))
00104     return ACE_Sig_Handler::signal_handlers_[signum];
00105   else
00106     return 0;
00107 }

ACE_Event_Handler * ACE_Sig_Handler::handler_i (  int  signum,
ACE_Event_Handler * 
)  [static, protected]
 

Set a new ACE_Event_Handler that is associated with signum. Return the existing handler. Does not acquire any locks so that it can be called from a signal handler, such as .

Definition at line 110 of file Sig_Handler.cpp.

References ACE_TRACE, in_range(), and signal_handlers_.

Referenced by handler(), and register_handler_i(). 

00112 {
00113   ACE_TRACE ("ACE_Sig_Handler::handler_i");
00114 
00115   if (ACE_Sig_Handler::in_range (signum))
00116     {
00117       ACE_Event_Handler *sh = ACE_Sig_Handler::signal_handlers_[signum];
00118 
00119       ACE_Sig_Handler::signal_handlers_[signum] = new_sh;
00120       return sh;
00121     }
00122   else
00123     return 0;
00124 }

ACE_INLINE int ACE_Sig_Handler::in_range (  int  signum  )  [static, protected]
 

Check whether the SIGNUM is within the legal range of signals.

Definition at line 11 of file Sig_Handler.inl.

References ACE_NSIG, and ACE_TRACE.

Referenced by dispatch(), handler(), handler_i(), ACE_Sig_Handlers::register_handler(), register_handler_i(), ACE_Sig_Handlers::remove_handler(), and remove_handler(). 

00012 {
00013   ACE_TRACE ("ACE_Sig_Handler::in_range");
00014   return signum > 0 && signum < ACE_NSIG;
00015 }

int ACE_Sig_Handler::register_handler (  int  signum,
ACE_Event_Handler *  new_sh,
ACE_Sig_Action *  new_disp = 0,
ACE_Event_Handler **  old_sh = 0,
ACE_Sig_Action *  old_disp = 0
)  [virtual]
 

Add a new ACE_Event_Handler and a new sigaction associated with signum. Passes back the existing ACE_Event_Handler and its sigaction if pointers are non-zero. Returns -1 on failure and >= 0 on success.

Reimplemented in ACE_Sig_Handlers.

Definition at line 183 of file Sig_Handler.cpp.

References ACE_TRACE, and register_handler_i().

Referenced by ACE_Async_Timer_Queue_Adapter< TQ >::ACE_Async_Timer_Queue_Adapter(), ACE_MMAP_Memory_Pool::ACE_MMAP_Memory_Pool(), ACE_Shared_Memory_Pool::ACE_Shared_Memory_Pool(), and ACE_Select_Reactor_T< ACE_SELECT_REACTOR_TOKEN >::register_handler(). 

00188 {
00189   ACE_TRACE ("ACE_Sig_Handler::register_handler");
00190   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00191     ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00192       (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00193     ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00194 
00195   return ACE_Sig_Handler::register_handler_i (signum,
00196                                               new_sh,
00197                                               new_disp,
00198                                               old_sh,
00199                                               old_disp);
00200 }

int ACE_Sig_Handler::register_handler_i (  int  signum,
ACE_Event_Handler *  new_sh,
ACE_Sig_Action *  new_disp = 0,
ACE_Event_Handler **  old_sh = 0,
ACE_Sig_Action *  old_disp = 0
)  [static, protected]
 

This implementation method is called by and dispatch. It doesn't do any locking so that it can be called within a signal handler, such as dispatch. It adds a new ACE_Event_Handler and a new sigaction associated with signum. Passes back the existing ACE_Event_Handler and its sigaction if pointers are non-zero. Returns -1 on failure and >= 0 on success.

Definition at line 144 of file Sig_Handler.cpp.

References ace_signal_handler_dispatcher, ACE_TRACE, ACE_Sig_Action::flags(), ACE_Sig_Action::handler(), handler_i(), in_range(), ACE_Sig_Action::register_action(), and SA_SIGINFO.

Referenced by dispatch(), and register_handler(). 

00149 {
00150   ACE_TRACE ("ACE_Sig_Handler::register_handler_i");
00151 
00152   if (ACE_Sig_Handler::in_range (signum))
00153     {
00154       ACE_Sig_Action sa; // Define a "null" action.
00155       ACE_Event_Handler *sh = ACE_Sig_Handler::handler_i (signum,
00156                                                           new_sh);
00157 
00158       // Return a pointer to the old <ACE_Sig_Handler> if the user
00159       // asks for this.
00160       if (old_sh != 0)
00161         *old_sh = sh;
00162 
00163       // Make sure that <new_disp> points to a valid location if the
00164       // user doesn't care...
00165       if (new_disp == 0)
00166         new_disp = &sa;
00167 
00168       new_disp->handler (ace_signal_handler_dispatcher);
00169 #if !defined (ACE_HAS_LYNXOS_SIGNALS)
00170       new_disp->flags (new_disp->flags () | SA_SIGINFO);
00171 #endif /* ACE_HAS_LYNXOS_SIGNALS */
00172       return new_disp->register_action (signum, old_disp);
00173     }
00174   else
00175     return -1;
00176 }

int ACE_Sig_Handler::remove_handler (  int  signum,
ACE_Sig_Action *  new_disp = 0,
ACE_Sig_Action *  old_disp = 0,
int  sigkey = -1
)  [virtual]
 

Remove the ACE_Event_Handler currently associated with signum. sigkey is ignored in this implementation since there is only one instance of a signal handler. Install the new disposition (if given) and return the previous disposition (if desired by the caller). Returns 0 on success and -1 if signum is invalid.

Reimplemented in ACE_Sig_Handlers.

Definition at line 205 of file Sig_Handler.cpp.

References ACE_TRACE, in_range(), ACE_Sig_Action::register_action(), SIG_DFL, and signal_handlers_.

Referenced by ACE_MMAP_Memory_Pool::handle_signal(), and ACE_Select_Reactor_T< ACE_SELECT_REACTOR_TOKEN >::remove_handler(). 

00209 {
00210   ACE_TRACE ("ACE_Sig_Handler::remove_handler");
00211   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00212     ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00213       (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00214     ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00215 
00216   if (ACE_Sig_Handler::in_range (signum))
00217     {
00218       ACE_Sig_Action sa (SIG_DFL, (sigset_t *) 0); // Define the default disposition.
00219 
00220       if (new_disp == 0)
00221         new_disp = &sa;
00222 
00223       ACE_Sig_Handler::signal_handlers_[signum] = 0;
00224 
00225       // Register either the new disposition or restore the default.
00226       return new_disp->register_action (signum, old_disp);
00227     }
00228 
00229     return -1;
00230 }

void ACE_Sig_Handler::sig_pending (  int   )  [static]
 

Reset the value of so that no signal is pending.

Definition at line 83 of file Sig_Handler.cpp.

References ACE_TRACE, and sig_pending_. 

00084 {
00085   ACE_TRACE ("ACE_Sig_Handler::sig_pending");
00086 
00087   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00088           ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00089           (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00090           ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00091   ACE_Sig_Handler::sig_pending_ = pending;
00092 }

int ACE_Sig_Handler::sig_pending (  void   )  [static]
 

True if there is a pending signal.

Definition at line 72 of file Sig_Handler.cpp.

References ACE_TRACE, and sig_pending_.

Referenced by ACE_Select_Reactor_T< ACE_SELECT_REACTOR_TOKEN >::dispatch(). 

00073 {
00074   ACE_TRACE ("ACE_Sig_Handler::sig_pending");
00075   ACE_MT (ACE_Recursive_Thread_Mutex *lock =
00076           ACE_Managed_Object<ACE_Recursive_Thread_Mutex>::get_preallocated_object
00077           (ACE_Object_Manager::ACE_SIG_HANDLER_LOCK);
00078           ACE_Guard<ACE_Recursive_Thread_Mutex> m (*lock));
00079   return ACE_Sig_Handler::sig_pending_ != 0;
00080 }

Member Data Documentation

ACE_Sig_Handler::ACE_ALLOC_HOOK_DECLARE
 

Declare the dynamic allocation hooks.

Reimplemented in ACE_Sig_Handlers.

Definition at line 105 of file Sig_Handler.h.

sig_atomic_t ACE_Sig_Handler::sig_pending_ = 0 [static, protected]
 

Keeps track of whether a signal is pending.

Definition at line 54 of file Sig_Handler.cpp.

Referenced by dispatch(), and sig_pending().

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_Event_Handler * ACE_Sig_Handler::signal_handlers_ [static, private]
 

Array used to store one user-defined Event_Handler for every signal.

Definition at line 51 of file Sig_Handler.cpp.

Referenced by dispatch(), handler(), handler_i(), and remove_handler().

The documentation for this class was generated from the following files:
Generated on Sun Jan 27 12:57:34 2008 for ACE by doxygen 1.3.6