Use libstddjb's selfpipe instead of signalfd

Use selfpipe in our client, server, and examples.

src/examples/Makefile.am

@@ -18,6 +18,8 @@ parse_LDADD = ../terminal/libmoshterminal.a ../util/libmoshutil.a -lutil $(BOOST
 termemu_SOURCES = termemu.cc
 termemu_CPPFLAGS = -I$(srcdir)/../terminal -I$(srcdir)/../util -I$(srcdir)/../statesync -I$(builddir)/../protobufs
 termemu_LDADD = ../terminal/libmoshterminal.a ../util/libmoshutil.a ../statesync/libmoshstatesync.a ../protobufs/libmoshprotos.a -lutil $(BOOST_LDFLAGS) $(protobuf_LIBS)
+termemu_CPPFLAGS += $(STDDJB_CPPFLAGS)
+termemu_LDADD += $(STDDJB_LDFLAGS)
 
 ntester_SOURCES = ntester.cc
 ntester_CPPFLAGS = -I$(srcdir)/../statesync -I$(srcdir)/../terminal -I$(srcdir)/../network -I$(srcdir)/../crypto -I$(builddir)/../protobufs $(BOOST_CPPFLAGS)

src/examples/termemu.cc

@@ -35,7 +35,6 @@
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-#include <sys/signalfd.h>
 #include <termios.h>
 #include <sys/types.h>
 #include <pwd.h>
@@ -51,6 +50,10 @@
 #include "completeterminal.h"
 #include "swrite.h"
 
+extern "C" {
+#include "selfpipe.h"
+}
+
 const size_t buf_size = 16384;
 
 void emulate_terminal( int fd );
@@ -193,19 +196,14 @@ bool tick( Terminal::Framebuffer &state, const Terminal::Framebuffer &new_frame
 void emulate_terminal( int fd )
 {
   /* establish WINCH fd and start listening for signal */
-  sigset_t signal_mask;
+  int signal_fd = selfpipe_init();
-  assert( sigemptyset( &signal_mask ) == 0 );
+  if ( signal_fd < 0 ) {
-  assert( sigaddset( &signal_mask, SIGWINCH ) == 0 );
+    perror( "selfpipe" );
-
-  /* stop "ignoring" WINCH signal */
-  assert( sigprocmask( SIG_BLOCK, &signal_mask, NULL ) == 0 );
-
-  int winch_fd = signalfd( -1, &signal_mask, 0 );
-  if ( winch_fd < 0 ) {
-    perror( "signalfd" );
     return;
   }
 
+  assert( selfpipe_trap(SIGWINCH) == 0 );
+
   /* get current window size */
   struct winsize window_size;
   if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {
@@ -231,7 +229,7 @@ void emulate_terminal( int fd )
   pollfds[ 1 ].fd = fd;
   pollfds[ 1 ].events = POLLIN;
 
-  pollfds[ 2 ].fd = winch_fd;
+  pollfds[ 2 ].fd = signal_fd;
   pollfds[ 2 ].events = POLLIN;
 
   swrite( STDOUT_FILENO, Terminal::Emulator::open().c_str() );
@@ -240,7 +238,9 @@ void emulate_terminal( int fd )
 
   while ( 1 ) {
     int active_fds = poll( pollfds, 3, poll_timeout );
-    if ( active_fds < 0 ) {
+    if ( active_fds < 0 && errno == EINTR ) {
+      continue;
+    } else if ( active_fds < 0 ) {
       perror( "poll" );
       break;
     }
@@ -287,9 +287,7 @@ void emulate_terminal( int fd )
       }
     } else if ( pollfds[ 2 ].revents & POLLIN ) {
       /* resize */
-      struct signalfd_siginfo info;
+      assert( selfpipe_read() == SIGWINCH );
-      assert( read( winch_fd, &info, sizeof( info ) ) == sizeof( info ) );
-      assert( info.ssi_signo == SIGWINCH );
 
       /* get new size */
       if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {

src/frontend/Makefile.am

@@ -1,6 +1,8 @@
 AM_CPPFLAGS = -I$(srcdir)/../statesync -I$(srcdir)/../terminal -I$(srcdir)/../network -I$(srcdir)/../crypto -I$(builddir)/../protobufs -I$(srcdir)/../util $(BOOST_CPPFLAGS) $(protobuf_CFLAGS)
 AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(PICKY_CXXFLAGS) -fno-default-inline -pipe
 LDADD = ../crypto/libmoshcrypto.a ../network/libmoshnetwork.a ../statesync/libmoshstatesync.a ../terminal/libmoshterminal.a ../util/libmoshutil.a ../protobufs/libmoshprotos.a -lutil -lm $(protobuf_LIBS)
+AM_CPPFLAGS += $(STDDJB_CPPFLAGS)
+LDADD += $(STDDJB_LDFLAGS)
 
 bin_PROGRAMS = mosh-client mosh-server
 

src/frontend/mosh-server.cc

@@ -18,13 +18,13 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <locale.h>
 #include <string.h>
 #include <langinfo.h>
 #include <termios.h>
 #include <unistd.h>
 #include <stdio.h>
-#include <pty.h>
 #include <stdlib.h>
 #include <poll.h>
 #include <sys/ioctl.h>
@@ -32,7 +32,6 @@
 #include <pwd.h>
 #include <typeinfo>
 #include <signal.h>
-#include <sys/signalfd.h>
 #ifdef HAVE_UTEMPTER
 #include <utempter.h>
 #endif
@@ -40,10 +39,20 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+extern "C" {
+#include "selfpipe.h"
+}
+
 #include "completeterminal.h"
 #include "swrite.h"
 #include "user.h"
 
+#if HAVE_PTY_H
+#include <pty.h>
+#elif HAVE_UTIL_H
+#include <util.h>
+#endif
+
 #include "networktransport.cc"
 
 typedef Network::Transport< Terminal::Complete, Network::UserStream > ServerConnection;
@@ -222,18 +231,15 @@ int main( int argc, char *argv[] )
 void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network )
 {
   /* establish fd for shutdown signals */
-  sigset_t signal_mask;
+  int signal_fd = selfpipe_init();
-
+  if ( signal_fd < 0 ) {
-  assert( sigemptyset( &signal_mask ) == 0 );
+    perror( "selfpipe" );
-  assert( sigaddset( &signal_mask, SIGTERM ) == 0 );
-  assert( sigaddset( &signal_mask, SIGINT ) == 0 );
-
-  int shutdown_signal_fd = signalfd( -1, &signal_mask, 0 );
-  if ( shutdown_signal_fd < 0 ) {
-    perror( "signalfd" );
     return;
   }
 
+  assert( selfpipe_trap( SIGTERM ) == 0 );
+  assert( selfpipe_trap( SIGINT ) == 0 );
+
   /* prepare to poll for events */
   struct pollfd pollfds[ 3 ];
 
@@ -243,7 +249,7 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
   pollfds[ 1 ].fd = host_fd;
   pollfds[ 1 ].events = POLLIN;
 
-  pollfds[ 2 ].fd = shutdown_signal_fd;
+  pollfds[ 2 ].fd = signal_fd;
   pollfds[ 2 ].events = POLLIN;
 
   uint64_t last_remote_num = network.get_remote_state_num();
@@ -266,7 +272,9 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
       }
 
       int active_fds = poll( pollfds, 3, poll_timeout );
-      if ( active_fds < 0 ) {
+      if ( active_fds < 0 && errno == EINTR ) {
+	continue;
+      } else if ( active_fds < 0 ) {
 	perror( "poll" );
 	break;
       }
@@ -364,12 +372,11 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
 
       if ( pollfds[ 2 ].revents & POLLIN ) {
 	/* shutdown signal */
-	struct signalfd_siginfo the_siginfo;
+	int signo = selfpipe_read();
-	ssize_t bytes_read = read( pollfds[ 2 ].fd, &the_siginfo, sizeof( the_siginfo ) );
+	if ( signo == 0 ) {
-	if ( bytes_read == 0 ) {
 	  break;
-	} else if ( bytes_read < 0 ) {
+	} else if ( signo < 0 ) {
-	  perror( "read" );
+	  perror( "selfpipe_read" );
 	  break;
 	}
 

src/frontend/stmclient.cc

@@ -18,6 +18,7 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <locale.h>
 #include <string.h>
 #include <langinfo.h>
@@ -29,7 +30,6 @@
 #include <sys/types.h>
 #include <pwd.h>
 #include <signal.h>
-#include <sys/signalfd.h>
 #include <time.h>
 
 #if HAVE_PTY_H
@@ -38,6 +38,10 @@
 #include <util.h>
 #endif
 
+extern "C" {
+#include "selfpipe.h"
+}
+
 #include "stmclient.h"
 #include "swrite.h"
 #include "completeterminal.h"
@@ -101,37 +105,21 @@ void STMClient::shutdown( void )
 void STMClient::main_init( void )
 {
   /* establish WINCH fd and start listening for signal */
-  sigset_t signal_mask;
+  signal_fd = selfpipe_init();
-  assert( sigemptyset( &signal_mask ) == 0 );
+  if ( signal_fd < 0 ) {
-  assert( sigaddset( &signal_mask, SIGWINCH ) == 0 );
+    perror( "selfpipe" );
-
-  /* stop "ignoring" WINCH signal */
-  assert( sigprocmask( SIG_BLOCK, &signal_mask, NULL ) == 0 );
-
-  winch_fd = signalfd( -1, &signal_mask, 0 );
-  if ( winch_fd < 0 ) {
-    perror( "signalfd" );
     return;
   }
 
+  assert( selfpipe_trap(SIGWINCH) == 0 );
+
   /* establish fd for shutdown signals */
-  assert( sigemptyset( &signal_mask ) == 0 );
+  assert( selfpipe_trap( SIGTERM ) == 0 );
-  assert( sigaddset( &signal_mask, SIGTERM ) == 0 );
+  assert( selfpipe_trap( SIGINT ) == 0 );
-  assert( sigaddset( &signal_mask, SIGINT ) == 0 );
+  assert( selfpipe_trap( SIGHUP ) == 0 );
-  assert( sigaddset( &signal_mask, SIGHUP ) == 0 );
+  assert( selfpipe_trap( SIGPIPE ) == 0 );
-  assert( sigaddset( &signal_mask, SIGPIPE ) == 0 );
+  assert( selfpipe_trap( SIGTSTP ) == 0 );
-  assert( sigaddset( &signal_mask, SIGTSTP ) == 0 );
+  assert( selfpipe_trap( SIGCONT ) == 0 );
-  assert( sigaddset( &signal_mask, SIGSTOP ) == 0 );
-  assert( sigaddset( &signal_mask, SIGCONT ) == 0 );
-
-  /* don't let signals kill us */
-  assert( sigprocmask( SIG_BLOCK, &signal_mask, NULL ) == 0 );
-
-  shutdown_signal_fd = signalfd( -1, &signal_mask, 0 );
-  if ( shutdown_signal_fd < 0 ) {
-    perror( "signalfd" );
-    return;
-  }
 
   /* get initial window size */
   if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {
@@ -256,10 +244,6 @@ bool STMClient::process_user_input( int fd )
 
 bool STMClient::process_resize( void )
 {
-  struct signalfd_siginfo info;
-  assert( read( winch_fd, &info, sizeof( info ) ) == sizeof( info ) );
-  assert( info.ssi_signo == SIGWINCH );
-  
   /* get new size */
   if ( ioctl( STDIN_FILENO, TIOCGWINSZ, &window_size ) < 0 ) {
     perror( "ioctl TIOCGWINSZ" );
@@ -287,7 +271,7 @@ void STMClient::main( void )
   main_init();
 
   /* prepare to poll for events */
-  struct pollfd pollfds[ 4 ];
+  struct pollfd pollfds[ 3 ];
 
   pollfds[ 0 ].fd = network->fd();
   pollfds[ 0 ].events = POLLIN;
@@ -295,18 +279,17 @@ void STMClient::main( void )
   pollfds[ 1 ].fd = STDIN_FILENO;
   pollfds[ 1 ].events = POLLIN;
 
-  pollfds[ 2 ].fd = winch_fd;
+  pollfds[ 2 ].fd = signal_fd;
   pollfds[ 2 ].events = POLLIN;
 
-  pollfds[ 3 ].fd = shutdown_signal_fd;
-  pollfds[ 3 ].events = POLLIN;
-
   while ( 1 ) {
     try {
       output_new_frame();
 
-      int active_fds = poll( pollfds, 4, min( network->wait_time(), overlays.wait_time() ) );
+      int active_fds = poll( pollfds, 3, min( network->wait_time(), overlays.wait_time() ) );
-      if ( active_fds < 0 ) {
+      if ( active_fds < 0 && errno == EINTR ) {
+	continue;
+      } else if ( active_fds < 0 ) {
 	perror( "poll" );
 	break;
       }
@@ -329,20 +312,13 @@ void STMClient::main( void )
       }
 
       if ( pollfds[ 2 ].revents & POLLIN ) {
+	int signo = selfpipe_read();
+
+	if ( signo == SIGWINCH ) {
 	  /* resize */
 	  if ( !process_resize() ) { return; }
-      }
+	} else if ( signo > 0 ) {
-
-      if ( pollfds[ 3 ].revents & POLLIN ) {
 	  /* shutdown signal */
-	struct signalfd_siginfo the_siginfo;
-	ssize_t bytes_read = read( pollfds[ 3 ].fd, &the_siginfo, sizeof( the_siginfo ) );
-	if ( bytes_read == 0 ) {
-	  break;
-	} else if ( bytes_read < 0 ) {
-	  perror( "read" );
-	  break;
-	}
 
 	  if ( !network->has_remote_addr() ) {
 	    break;
@@ -351,6 +327,7 @@ void STMClient::main( void )
 	    network->start_shutdown();
 	  }
 	}
+      }
 
       if ( (pollfds[ 0 ].revents)
 	   & (POLLERR | POLLHUP | POLLNVAL) ) {

src/frontend/stmclient.h

@@ -36,7 +36,7 @@ private:
 
   struct termios saved_termios, raw_termios;
 
-  int winch_fd, shutdown_signal_fd;
+  int signal_fd;
   struct winsize window_size;
 
   Terminal::Framebuffer *local_framebuffer;
@@ -56,7 +56,7 @@ public:
   STMClient( const char *s_ip, int s_port, const char *s_key, const char *predict_mode )
     : ip( s_ip ), port( s_port ), key( s_key ),
       saved_termios(), raw_termios(),
-      winch_fd(), shutdown_signal_fd(),
+      signal_fd(),
       window_size(),
       local_framebuffer( NULL ),
       overlays(),