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Diffstat (limited to 'ACE/ace/Sig_Handler.h')
| -rw-r--r-- | ACE/ace/Sig_Handler.h | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/ACE/ace/Sig_Handler.h b/ACE/ace/Sig_Handler.h new file mode 100644 index 00000000000..3e7e80891d3 --- /dev/null +++ b/ACE/ace/Sig_Handler.h @@ -0,0 +1,237 @@ +// -*- C++ -*- + +//============================================================================= +/** + * @file Sig_Handler.h + * + * $Id$ + * + * @author Douglas C. Schmidt <schmidt@cs.wustl.edu> + */ +//============================================================================= + +#ifndef ACE_SIGNAL_HANDLER_H +#define ACE_SIGNAL_HANDLER_H +#include /**/ "ace/pre.h" + +#include /**/ "ace/ACE_export.h" + +#if !defined (ACE_LACKS_PRAGMA_ONCE) +# pragma once +#endif /* ACE_LACKS_PRAGMA_ONCE */ + +#include "ace/Event_Handler.h" + +ACE_BEGIN_VERSIONED_NAMESPACE_DECL + +class ACE_Sig_Action; + +/** + * @class ACE_Sig_Handler + * + * @brief 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 + * @a signum. When a signal occurs that corresponds to this + * @a signum, the @c handle_signal method of the registered + * ACE_Event_Handler is invoked automatically. + */ +class ACE_Export ACE_Sig_Handler +{ +public: + /// Default constructor. + ACE_Sig_Handler (void); + + /// Destructor + virtual ~ACE_Sig_Handler (void); + + // = Registration and removal methods. + /** + * Add a new ACE_Event_Handler and a new sigaction associated with + * @a signum. Passes back the existing ACE_Event_Handler and its + * sigaction if pointers are non-zero. Returns -1 on failure and >= + * 0 on success. + */ + 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); + + /** + * Remove the ACE_Event_Handler currently associated with + * @a signum. @a 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 @a signum + * is invalid. + */ + virtual int remove_handler (int signum, + ACE_Sig_Action *new_disp = 0, + ACE_Sig_Action *old_disp = 0, + int sigkey = -1); + + // Set/get signal status. + /// True if there is a pending signal. + static int sig_pending (void); + + /// Reset the value of <sig_pending_> so that no signal is pending. + static void sig_pending (int); + + // = Set/get the handler associated with a particular signal. + + /// Return the ACE_Sig_Handler associated with @a signum. + virtual ACE_Event_Handler *handler (int signum); + + /// Set a new ACE_Event_Handler that is associated with @a signum. + /// Return the existing handler. + virtual ACE_Event_Handler *handler (int signum, ACE_Event_Handler *); + + /** + * Callback routine registered with sigaction(2) that dispatches the + * <handle_signal> method of the appropriate pre-registered + * ACE_Event_Handler. + */ + static void dispatch (int, siginfo_t *, + ucontext_t *); + + /// Dump the state of an object. + void dump (void) const; + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + +protected: + // = These methods and data members are shared by derived classes. + + /** + * Set a new ACE_Event_Handler that is associated with @a signum. + * Return the existing handler. Does not acquire any locks so that + * it can be called from a signal handler, such as <dispatch>. + */ + static ACE_Event_Handler *handler_i (int signum, + ACE_Event_Handler *); + + /** + * This implementation method is called by <register_handler> and + * @c dispatch. It doesn't do any locking so that it can be called + * within a signal handler, such as @c dispatch. It adds a new + * ACE_Event_Handler and a new sigaction associated with @a signum. + * Passes back the existing ACE_Event_Handler and its sigaction if + * pointers are non-zero. Returns -1 on failure and >= 0 on + * success. + */ + static 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); + + /// Check whether the SIGNUM is within the legal range of signals. + static int in_range (int signum); + + /// Keeps track of whether a signal is pending. + static sig_atomic_t sig_pending_; + +private: + /// Array used to store one user-defined Event_Handler for every + /// signal. + static ACE_Event_Handler *signal_handlers_[ACE_NSIG]; +}; + +/** + * @class ACE_Sig_Handlers + * + * @brief This is an alternative signal handling dispatcher for ACE. It + * allows a list of signal handlers to be registered for each + * signal. It also makes SA_RESTART the default mode. + * + * Using this class a program can register one or more + * ACE_Event_Handler with the ACE_Sig_Handler in order to + * handle a designated @a signum. When a signal occurs that + * corresponds to this @a signum, the <handle_signal> methods of + * all the registered ACE_Event_Handlers are invoked + * automatically. + */ +class ACE_Export ACE_Sig_Handlers : public ACE_Sig_Handler +{ +public: + // = Registration and removal methods. + /** + * Add a new ACE_Event_Handler and a new sigaction associated with + * @a signum. Passes back the existing ACE_Event_Handler and its + * sigaction if pointers are non-zero. Returns -1 on failure and + * a <sigkey> that is >= 0 on success. + */ + 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); + + /** + * Remove an ACE_Event_Handler currently associated with @a signum. + * We remove the handler if (1) its sigkey> matches the @a sigkey + * passed as a parameter or (2) if we've been told to remove all the + * handlers, i.e., @a sigkey == -1. If a new disposition is given it + * is installed and the previous disposition is returned (if desired + * by the caller). Returns 0 on success and -1 if @a signum is + * invalid. + */ + virtual int remove_handler (int signum, + ACE_Sig_Action *new_disp = 0, + ACE_Sig_Action *old_disp = 0, + int sigkey = -1); + + // = Set/get the handler associated with a particular signal. + + /// Return the head of the list of <ACE_Sig_Handler>s associated with + /// SIGNUM. + virtual ACE_Event_Handler *handler (int signum); + + /** + * Set a new ACE_Event_Handler that is associated with SIGNUM at + * the head of the list of signals. Return the existing handler + * that was at the head. + */ + virtual ACE_Event_Handler *handler (int signum, + ACE_Event_Handler *); + + /** + * Callback routine registered with sigaction(2) that dispatches the + * <handle_signal> method of all the pre-registered + * ACE_Event_Handlers for @a signum + */ + static void dispatch (int signum, siginfo_t *, ucontext_t *); + + /// Dump the state of an object. + void dump (void) const; + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + +private: + /** + * Keeps track of the id that uniquely identifies each registered + * signal handler. This id can be used to cancel a timer via the + * <remove_handler> method. + */ + static int sigkey_; + + /// If this is true then a 3rd party library has registered a + /// handler... + static bool third_party_sig_handler_; +}; + +ACE_END_VERSIONED_NAMESPACE_DECL + +#if defined (__ACE_INLINE__) +#include "ace/Sig_Handler.inl" +#endif /* __ACE_INLINE__ */ + +#include /**/ "ace/post.h" +#endif /* ACE_SIG_HANDLER_H */ |