Make all exception classes inherit from std::exception

This refactors out a very common pattern of formatting "%s: %s" with
e.function.c_str() and strerror( e.the_errno ) into just the what()
method of NetworkException. It's also a prerequisite for making cleaner
public API for any exceptions we throw, and allows us to more easily
get exceptions passed back to us to handle.

src/crypto/crypto.h

@@ -38,18 +38,21 @@
 #include <string.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <exception>
 
 using std::string;
 
 long int myatoi( const char *str );
 
 namespace Crypto {
-  class CryptoException {
+  class CryptoException : public std::exception {
   public:
     string text;
     bool fatal;
     CryptoException( string s_text, bool s_fatal = false )
       : text( s_text ), fatal( s_fatal ) {};
+    const char *what() const throw () { return text.c_str(); }
+    ~CryptoException() throw () {}
   };
 
   /* 16-byte-aligned buffer, with length. */

src/examples/decrypt.cc

@@ -62,7 +62,7 @@ int main( int argc, char *argv[] )
 	     (long)message.nonce.val() );
     cout << message.text;
   } catch ( const CryptoException &e ) {
-    cerr << e.text << endl;
+    cerr << e.what() << endl;
     exit( 1 );
   }
 

src/examples/encrypt.cc

@@ -63,7 +63,7 @@ int main( int argc, char *argv[] )
 
     cout << ciphertext;
   } catch ( const CryptoException &e ) {
-    cerr << e.text << endl;
+    cerr << e.what() << endl;
     exit( 1 );
   }
 

src/examples/ntester.cc

@@ -66,7 +66,7 @@ int main( int argc, char *argv[] )
       n = new Transport<UserStream, UserStream>( me, remote, NULL, NULL );
     }
   } catch ( const CryptoException &e ) {
-    fprintf( stderr, "Fatal error: %s\n", e.text.c_str() );
+    fprintf( stderr, "Fatal error: %s\n", e.what() );
     exit( 1 );
   }
 
@@ -98,7 +98,7 @@ int main( int argc, char *argv[] )
 	  }
 	}
       } catch ( const CryptoException &e ) {
-	fprintf( stderr, "Cryptographic error: %s\n", e.text.c_str() );
+	fprintf( stderr, "Cryptographic error: %s\n", e.what() );
       }
     }
   } else {
@@ -164,10 +164,10 @@ int main( int argc, char *argv[] )
 	  n->recv();
 	}
       } catch ( const NetworkException &e ) {
-	fprintf( stderr, "%s: %s\r\n", e.function.c_str(), strerror( e.the_errno ) );
+	fprintf( stderr, "%s\n", e.what() );
 	break;
       } catch ( const CryptoException &e ) {
-	fprintf( stderr, "Cryptographic error: %s\n", e.text.c_str() );
+	fprintf( stderr, "Cryptographic error: %s\n", e.what() );
       }
     }
 

src/frontend/mosh-client.cc

@@ -34,7 +34,6 @@
 #include "version.h"
 
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 #include "stmclient.h"
@@ -177,11 +176,11 @@ int main( int argc, char *argv[] )
 
     client.shutdown();
   } catch ( const Network::NetworkException& e ) {
-    fprintf( stderr, "Network exception: %s: %s\r\n",
-	     e.function.c_str(), strerror( e.the_errno ) );
+    fprintf( stderr, "Network exception: %s\r\n",
+	     e.what() );
   } catch ( const Crypto::CryptoException& e ) {
     fprintf( stderr, "Crypto exception: %s\r\n",
-	     e.text.c_str() );
+	     e.what() );
   } catch ( const std::string& s ) {
     fprintf( stderr, "Error: %s\r\n", s.c_str() );
   }

src/frontend/mosh-server.cc

@@ -311,12 +311,12 @@ int main( int argc, char *argv[] )
   try {
     return run_server( desired_ip, desired_port, command_path, command_argv, colors, verbose, with_motd );
   } catch ( const Network::NetworkException& e ) {
-    fprintf( stderr, "Network exception: %s: %s\n",
-	     e.function.c_str(), strerror( e.the_errno ) );
+    fprintf( stderr, "Network exception: %s\n",
+	     e.what() );
     return 1;
   } catch ( const Crypto::CryptoException& e ) {
     fprintf( stderr, "Crypto exception: %s\n",
-	     e.text.c_str() );
+	     e.what() );
     return 1;
   }
 }
@@ -491,11 +491,11 @@ int run_server( const char *desired_ip, const char *desired_port,
     try {
       serve( master, terminal, *network );
     } catch ( const Network::NetworkException& e ) {
-      fprintf( stderr, "Network exception: %s: %s\n",
-	       e.function.c_str(), strerror( e.the_errno ) );
+      fprintf( stderr, "Network exception: %s\n",
+	       e.what() );
     } catch ( const Crypto::CryptoException& e ) {
       fprintf( stderr, "Crypto exception: %s\n",
-	       e.text.c_str() );
+	       e.what() );
     }
 
     #ifdef HAVE_UTEMPTER
@@ -727,13 +727,13 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
 
       network.tick();
     } catch ( const Network::NetworkException& e ) {
-      fprintf( stderr, "%s: %s\n", e.function.c_str(), strerror( e.the_errno ) );
+      fprintf( stderr, "%s\n", e.what() );
       spin();
     } catch ( const Crypto::CryptoException& e ) {
       if ( e.fatal ) {
         throw;
       } else {
-        fprintf( stderr, "Crypto exception: %s\n", e.text.c_str() );
+        fprintf( stderr, "Crypto exception: %s\n", e.what() );
       }
     }
   }

src/frontend/stmclient.cc

@@ -568,7 +568,7 @@ void STMClient::main( void )
         throw;
       } else {
         wchar_t tmp[ 128 ];
-        swprintf( tmp, 128, L"Crypto exception: %s", e.text.c_str() );
+        swprintf( tmp, 128, L"Crypto exception: %s", e.what() );
         overlays.get_notification_engine().set_notification_string( wstring( tmp ) );
       }
     }

src/frontend/terminaloverlay.h

@@ -40,6 +40,7 @@
 
 #include <vector>
 #include <limits.h>
+#include <exception>
 
 namespace Overlay {
   using namespace Terminal;
@@ -173,10 +174,10 @@ namespace Overlay {
       show_quit_keystroke = s_show_quit_keystroke;
     }
 
-    void set_network_exception( const NetworkException &e )
+    void set_network_exception( const std::exception &e )
     {
       wchar_t tmp[ 128 ];
-      swprintf( tmp, 128, L"%s: %s", e.function.c_str(), strerror( e.the_errno ) );
+      swprintf( tmp, 128, L"%s", e.what() );
 
       message = tmp;
       message_is_network_exception = true;

src/network/network.cc

@@ -260,9 +260,9 @@ Connection::Connection( const char *desired_ip, const char *desired_port ) /* se
     try {
       if ( try_bind( desired_ip, desired_port_low, desired_port_high ) ) { return; }
     } catch ( const NetworkException& e ) {
-      fprintf( stderr, "Error binding to IP %s: %s: %s\n",
+      fprintf( stderr, "Error binding to IP %s: %s\n",
 	       desired_ip,
-	       e.function.c_str(), strerror( e.the_errno ) );
+	       e.what() );
     }
   }
 
@@ -270,8 +270,8 @@ Connection::Connection( const char *desired_ip, const char *desired_port ) /* se
   try {
     if ( try_bind( NULL, desired_port_low, desired_port_high ) ) { return; }
   } catch ( const NetworkException& e ) {
-    fprintf( stderr, "Error binding to any interface: %s: %s\n",
-	     e.function.c_str(), strerror( e.the_errno ) );
+    fprintf( stderr, "Error binding to any interface: %s\n",
+	     e.what() );
     throw; /* this time it's fatal */
   }
 

src/network/network.h

@@ -41,6 +41,8 @@
 #include <math.h>
 #include <vector>
 #include <assert.h>
+#include <exception>
+#include <string.h>
 
 #include "crypto.h"
 
@@ -53,12 +55,18 @@ namespace Network {
   uint16_t timestamp16( void );
   uint16_t timestamp_diff( uint16_t tsnew, uint16_t tsold );
 
-  class NetworkException {
+  class NetworkException : public std::exception {
   public:
     string function;
     int the_errno;
-    NetworkException( string s_function, int s_errno ) : function( s_function ), the_errno( s_errno ) {}
-    NetworkException() : function( "<none>" ), the_errno( 0 ) {}
+  private:
+    string my_what;
+  public:
+    NetworkException( string s_function="<none>", int s_errno=0)
+      : function( s_function ), the_errno( s_errno ),
+        my_what(function + ": " + strerror(the_errno)) {}
+    const char *what() const throw () { return my_what.c_str(); }
+    ~NetworkException() throw () {}
   };
 
   enum Direction {

src/tests/encrypt-decrypt.cc

@@ -144,7 +144,7 @@ int main( int argc, char *argv[] ) {
       test_one_session();
     } catch ( const CryptoException& e ) {
       fprintf( stderr, "Crypto exception: %s\r\n",
-               e.text.c_str() );
+               e.what() );
       fatal_assert( false );
     }
   }