diff options
| author | Jeffrey Walton <noloader@gmail.com> | 2016-09-17 12:23:02 -0400 |
|---|---|---|
| committer | Jeffrey Walton <noloader@gmail.com> | 2016-09-17 12:23:02 -0400 |
| commit | 3815b908ab669331ff99f3599086d69967dd43c6 (patch) | |
| tree | 54cca57b58a6a9a81de3df9d35c962a601fcfd0f /ossig.h | |
| parent | 91ca6c117de7ce68526e96f4f75e4813c69577dc (diff) | |
| download | cryptopp-git-3815b908ab669331ff99f3599086d69967dd43c6.tar.gz | |
Add ossig.h. Move SignalHandler to ossig.h
This avoids a circular dependency between misc.h and trap.h. It also allows us to logically segregate and group code to replace C++ handlers, like set_terminate
Diffstat (limited to 'ossig.h')
| -rw-r--r-- | ossig.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/ossig.h b/ossig.h new file mode 100644 index 00000000..44a74a5b --- /dev/null +++ b/ossig.h @@ -0,0 +1,112 @@ +// ossig.h - written and placed in the public domain by Jeffrey Walton
+// Copyright assigned to Crypto++ project.
+
+//! \file ossig.h
+//! \brief Utility class for trapping OS signals.
+//! \since Crypto++ 5.6.5
+
+#ifndef CRYPTOPP_OS_SIGNAL_H
+#define CRYPTOPP_OS_SIGNAL_H
+
+#include "config.h"
+
+#if defined(CRYPTOPP_BSD_AVAILABLE) || defined(CRYPTOPP_UNIX_AVAILABLE)
+# include <signal.h>
+#endif
+
+NAMESPACE_BEGIN(CryptoPP)
+
+// ************** Unix and Linux compatibles ***************
+
+#if defined(CRYPTOPP_BSD_AVAILABLE) || defined(CRYPTOPP_UNIX_AVAILABLE) || defined(CRYPTOPP_DOXYGEN_PROCESSING)
+//! \brief Signal handler function pointer
+//! \sa SignalHandler
+extern "C" {
+ typedef void (*SignalHandlerFn) (int);
+};
+
+//! Signal handler for Linux and Unix compatibles
+//! \tparam S Signal number
+//! \tparam O Flag indicating exsting handler should be overwriiten
+//! \details SignalHandler() can be used to install a signal handler with the signature
+//! <tt>void handler_fn(int)</tt>. If <tt>SignalHandlerFn</tt> is not <tt>NULL</tt>, then
+//! the sigaction is set to the function and the sigaction flags is set to the flags.
+//! If <tt>SignalHandlerFn</tt> is <tt>NULL</tt>, then a default handler is installed
+//! using sigaction flags set to 0. The default handler only returns from the call.
+//! \details Upon destruction the previous signal handler is restored if the former signal handler
+//! was replaced.
+//! \warning Do not use SignalHandler in a code block that uses <tt>setjmp</tt> or <tt>longjmp</tt>
+//! because the destructor may not run.
+//! \since Crypto++ 5.6.5
+//! \sa SignalHandlerFn, \ref CRYPTOPP_ASSERT "CRYPTOPP_ASSERT", DebugTrapHandler
+template <int S, bool O=false>
+struct SignalHandler
+{
+ //! \brief Construct a signal handler
+ //! \param pfn Pointer to a signal handler function
+ //! \param flags Flags to use with the signal handler
+ //! \details SignalHandler() installs a signal handler with the signature
+ //! <tt>void handler_fn(int)</tt>. If <tt>SignalHandlerFn</tt> is not <tt>NULL</tt>, then
+ //! the sigaction is set to the function and the sigaction flags is set to the flags.
+ //! If <tt>SignalHandlerFn</tt> is <tt>NULL</tt>, then a default handler is installed
+ //! using sigaction flags set to 0. The default handler only returns from the call.
+ //! \details Upon destruction the previous signal handler is restored if the former signal handler
+ //! was overwritten.
+ //! \warning Do not use SignalHandler in a code block that uses <tt>setjmp</tt> or <tt>longjmp</tt>
+ //! because the destructor may not run. <tt>setjmp</tt> is why cpu.cpp does not use SignalHandler
+ //! during CPU feature testing.
+ //! \since Crypto++ 5.6.5
+ SignalHandler(SignalHandlerFn pfn = 0, int flags = 0) : m_installed(false)
+ {
+ // http://pubs.opengroup.org/onlinepubs/007908799/xsh/sigaction.html
+ struct sigaction new_handler;
+ // memset(&new_handler, 0x00, sizeof(new_handler));
+
+ do
+ {
+ int ret = 0;
+
+ ret = sigaction (S, 0, &m_old);
+ if (ret != 0) break; // Failed
+
+ // Don't step on another's handler if Overwrite=false
+ if (m_old.sa_handler != 0 && !O) break;
+
+ // Set up the structure to specify the action.
+ new_handler.sa_handler = (pfn ? pfn : &SignalHandler::NullHandler);
+ new_handler.sa_flags = (pfn ? flags : 0);
+
+ ret = sigemptyset (&new_handler.sa_mask);
+ if (ret != 0) break; // Failed
+
+ // Install it
+ ret = sigaction (S, &new_handler, 0);
+ if (ret != 0) break; // Failed
+
+ m_installed = true;
+
+ } while(0);
+ }
+
+ ~SignalHandler()
+ {
+ if (m_installed)
+ sigaction (S, &m_old, 0);
+ }
+
+private:
+ struct sigaction m_old;
+ bool m_installed;
+
+ static void NullHandler(int /*unused*/) { /* continue*/ }
+
+private:
+ // Not copyable
+ SignalHandler(const SignalHandler &);
+ void operator=(const SignalHandler &);
+};
+#endif
+
+NAMESPACE_END
+
+#endif // CRYPTOPP_OS_SIGNAL_H
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