Simple actions dispatching on terminal emulator

termemu.cpp

@@ -0,0 +1,186 @@
+#include <pty.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <errno.h>
+#include <poll.h>
+#include <string.h>
+#include <locale.h>
+#include <langinfo.h>
+#include <wchar.h>
+#include <assert.h>
+#include <wctype.h>
+#include <iostream>
+#include <typeinfo>
+
+#include "terminal.hpp"
+
+#ifndef __STDC_ISO_10646__
+#error "Must have __STDC_ISO_10646__"
+#endif
+
+const size_t buf_size = 1024;
+
+void emulate_terminal( int fd );
+int copy( int src, int dest );
+int termemu( int fd, Terminal::Emulator *terminal );
+
+int main( int argc __attribute__((unused)),
+	  char *argv[] __attribute__((unused)),
+	  char *envp[] )
+{
+  int master;
+  struct termios saved_termios, raw_termios, child_termios;
+
+  if ( NULL == setlocale( LC_ALL, "" ) ) {
+    perror( "setlocale" );
+    exit( 1 );
+  }
+
+  if ( strcmp( nl_langinfo( CODESET ), "UTF-8" ) != 0 ) {
+    fprintf( stderr, "rtm requires a UTF-8 locale.\n" );
+    exit( 1 );
+  }
+
+  if ( tcgetattr( STDIN_FILENO, &saved_termios ) < 0 ) {
+    perror( "tcgetattr" );
+    exit( 1 );
+  }
+
+  child_termios = saved_termios;
+
+  if ( !(child_termios.c_iflag & IUTF8) ) {
+    fprintf( stderr, "Warning: Locale is UTF-8 but termios IUTF8 flag not set. Setting IUTF8 flag.\n" );
+    child_termios.c_iflag |= IUTF8;
+  }
+
+  pid_t child = forkpty( &master, NULL, &child_termios, NULL );
+
+  if ( child == -1 ) {
+    perror( "forkpty" );
+    exit( 1 );
+  }
+
+  if ( child == 0 ) {
+    /* child */
+    if ( chdir( "/" ) < 0 ) {
+      perror( "chdir" );
+      exit( 1 );
+    }
+
+    char *my_argv[ 2 ];
+    my_argv[ 0 ] = strdup( "/bin/bash" );
+    assert( my_argv[ 0 ] );
+
+    my_argv[ 1 ] = NULL;
+
+    if ( execve( "/bin/bash", my_argv, envp ) < 0 ) {
+      perror( "execve" );
+      exit( 1 );
+    }
+    exit( 0 );
+  } else {
+    /* parent */
+    raw_termios = saved_termios;
+
+    cfmakeraw( &raw_termios );
+
+    if ( tcsetattr( STDIN_FILENO, TCSANOW, &raw_termios ) < 0 ) {
+      perror( "tcsetattr" );
+      exit( 1 );
+    }
+
+    emulate_terminal( master );
+
+    if ( tcsetattr( STDIN_FILENO, TCSANOW, &saved_termios ) < 0 ) {
+      perror( "tcsetattr" );
+      exit( 1 );
+    }
+  }
+
+  return 0;
+}
+
+void emulate_terminal( int fd )
+{
+  Terminal::Emulator terminal( 80, 24 );
+  struct pollfd pollfds[ 2 ];
+
+  pollfds[ 0 ].fd = STDIN_FILENO;
+  pollfds[ 0 ].events = POLLIN;
+
+  pollfds[ 1 ].fd = fd;
+  pollfds[ 1 ].events = POLLIN;
+
+  while ( 1 ) {
+    int active_fds = poll( pollfds, 2, -1 );
+    if ( active_fds <= 0 ) {
+      perror( "poll" );
+      return;
+    }
+
+    if ( pollfds[ 0 ].revents & POLLIN ) {
+      if ( copy( STDIN_FILENO, fd ) < 0 ) {
+	return;
+      }
+    } else if ( pollfds[ 1 ].revents & POLLIN ) {
+      if ( termemu( fd, &terminal ) < 0 ) {
+	return;
+      }
+    } else if ( (pollfds[ 0 ].revents | pollfds[ 1 ].revents)
+		& (POLLERR | POLLHUP | POLLNVAL) ) {
+      return;
+    } else {
+      fprintf( stderr, "poll mysteriously woken up\n" );
+    }
+  }
+}
+
+int copy( int src, int dest )
+{
+  char buf[ buf_size ];
+
+  ssize_t bytes_read = read( src, buf, buf_size );
+  if ( bytes_read == 0 ) { /* EOF */
+    return -1;
+  } else if ( bytes_read < 0 ) {
+    perror( "read" );
+    return -1;
+  } else {
+    ssize_t total_bytes_written = 0;
+    while ( total_bytes_written < bytes_read ) {
+      ssize_t bytes_written = write( dest, buf + total_bytes_written,
+				     bytes_read - total_bytes_written );
+      if ( bytes_written <= 0 ) {
+	perror( "write" );
+	return -1;
+      } else {
+	total_bytes_written += bytes_written;
+      }
+    }
+  }
+
+  return 0;
+}
+
+int termemu( int fd, Terminal::Emulator *terminal )
+{
+  char buf[ buf_size ];
+
+  /* fill buffer if possible */
+  ssize_t bytes_read = read( fd, buf, buf_size );
+  if ( bytes_read == 0 ) { /* EOF */
+    return -1;
+  } else if ( bytes_read < 0 ) {
+    perror( "read" );
+    return -1;
+  }
+
+  /* feed to terminal */
+  for ( int i = 0; i < bytes_read; i++ ) {
+    terminal->input( buf[ i ] );
+  }
+
+  return 0;
+}