Make utmp entries using utempter

configure.ac

@@ -12,6 +12,7 @@ AC_PROG_CXX
 AC_PROG_RANLIB
 
 # Checks for libraries.
+AC_SEARCH_LIBS([utempter_remove_added_record], [utempter], , AC_MSG_ERROR([Unable to find libutempter.]))
 
 # Checks for header files.
 AC_CHECK_HEADERS([arpa/inet.h fcntl.h langinfo.h limits.h locale.h netinet/in.h stddef.h stdint.h stdlib.h string.h sys/ioctl.h sys/socket.h sys/time.h termios.h unistd.h wchar.h wctype.h])

debian/control

@@ -2,7 +2,7 @@ Source: mosh
 Section: net
 Priority: optional
 Maintainer: Keith Winstein <keithw@mit.edu>
-Build-Depends: debhelper (>= 8.0.0), autotools-dev, protobuf-compiler, libprotobuf-dev, dh-autoreconf, pkg-config
+Build-Depends: debhelper (>= 8.0.0), autotools-dev, protobuf-compiler, libprotobuf-dev, dh-autoreconf, pkg-config, libutempter-dev
 Standards-Version: 3.9.2
 Homepage: http://mosh.mit.edu
 Vcs-Git: git://github.com/keithw/mosh.git
@@ -10,7 +10,7 @@ Vcs-Browser: http://github.com/keithw/mosh
 
 Package: mosh
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}, libprotobuf-lite7, libio-pty-perl, openssh-client
+Depends: ${shlibs:Depends}, ${misc:Depends}, libprotobuf-lite7, libio-pty-perl, openssh-client, libutempter0
 Description: Mobile shell that supports roaming and intelligent local echo
  Mosh is a remote terminal application that supports:
    - intermittent network connectivity,

src/frontend/Makefile.am

@@ -1,7 +1,7 @@
 AM_CPPFLAGS = -I$(srcdir)/../statesync -I$(srcdir)/../terminal -I$(srcdir)/../network -I$(srcdir)/../crypto -I$(builddir)/../protobufs -I$(srcdir)/../util
 AM_CXXFLAGS = --std=c++0x -pedantic -Werror -Wall -Wextra -Weffc++ -fno-default-inline -pipe
 LIBS = $(protobuf_lite_LIBS)
-LDADD = ../crypto/libmoshcrypto.a ../network/libmoshnetwork.a ../statesync/libmoshstatesync.a ../terminal/libmoshterminal.a ../util/libmoshutil.a ../protobufs/libmoshprotos.a -lutil -lrt -lm
+LDADD = ../crypto/libmoshcrypto.a ../network/libmoshnetwork.a ../statesync/libmoshstatesync.a ../terminal/libmoshterminal.a ../util/libmoshutil.a ../protobufs/libmoshprotos.a -lutil -lrt -lm -lutempter
 
 bin_PROGRAMS = mosh-client mosh-server
 

src/frontend/mosh-server.cc

@@ -31,6 +31,10 @@
 #include <typeinfo>
 #include <signal.h>
 #include <sys/signalfd.h>
+#include <utempter.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
 
 #include "completeterminal.h"
 #include "swrite.h"
@@ -126,7 +130,7 @@ int main( int argc, char *argv[] )
   }
 
   /* Fork child process */
-  pid_t child = forkpty( &master, NULL, &child_termios, NULL );
+  pid_t child = forkpty( &master, NULL, &child_termios, &window_size );
 
   if ( child == -1 ) {
     perror( "forkpty" );
@@ -178,6 +182,11 @@ int main( int argc, char *argv[] )
     exit( 0 );
   } else {
     /* parent */
+    /* make utmp entry */
+    char tmp[ 64 ];
+    snprintf( tmp, 64, "mosh [%d]", getpid() );
+    utempter_add_record( master, tmp );
+
     try {
       serve( master, terminal, network );
     } catch ( Network::NetworkException e ) {
@@ -192,6 +201,8 @@ int main( int argc, char *argv[] )
       perror( "close" );
       exit( 1 );
     }
+
+    utempter_remove_added_record();
   }
 
   printf( "\n[mosh-server is exiting.]\n" );
@@ -228,6 +239,10 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
 
   uint64_t last_remote_num = network.get_remote_state_num();
 
+  bool connected_utmp = false;
+  struct in_addr saved_addr;
+  saved_addr.s_addr = 0;
+
   while ( 1 ) {
     try {
       int active_fds = poll( pollfds, 3, network.wait_time() );
@@ -271,6 +286,20 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
 	  if ( swrite( host_fd, terminal_to_host.c_str(), terminal_to_host.length() ) < 0 ) {
 	    break;
 	  }
+
+	  /* update utmp entry if we have become "connected" */
+	  if ( (!connected_utmp)
+	       || ( saved_addr.s_addr != network.get_remote_ip().s_addr ) ) {
+	    utempter_remove_added_record();
+
+	    saved_addr = network.get_remote_ip();
+
+	    char tmp[ 64 ];
+	    snprintf( tmp, 64, "%s via mosh [%d]", inet_ntoa( saved_addr ), getpid() );
+	    utempter_add_record( host_fd, tmp );
+
+	    connected_utmp = true;
+	  }
 	}
       }
       
@@ -350,6 +379,19 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
 	break;
       }
 
+      /* update utmp if has been more than 10 seconds since heard from client */
+      if ( connected_utmp ) {
+	if ( network.get_latest_remote_state().timestamp < Network::timestamp() - 10000 ) {
+	  utempter_remove_added_record();
+
+	  char tmp[ 64 ];
+	  snprintf( tmp, 64, "mosh [%d]", getpid() );
+	  utempter_add_record( host_fd, tmp );
+
+	  connected_utmp = false;
+	}
+      }
+
       network.tick();
     } catch ( Network::NetworkException e ) {
       fprintf( stderr, "%s: %s\n", e.function.c_str(), strerror( e.the_errno ) );

src/network/network.h

@@ -117,6 +117,8 @@ namespace Network {
 
     uint64_t timeout( void ) const;
     double get_SRTT( void ) const { return SRTT; }
+
+    const struct in_addr & get_remote_ip( void ) const { return remote_addr.sin_addr; }
   };
 }
 

src/network/networktransport.h

@@ -101,6 +101,8 @@ namespace Network {
     uint64_t get_sent_state_late_acked( void ) const { return sent_state_late_acked; }
 
     unsigned int send_interval( void ) const { return sender.send_interval(); }
+
+    const struct in_addr & get_remote_ip( void ) const { return connection.get_remote_ip(); }
   };
 }