Merge pull request #898 from MichaelRiss/selectFix

select function: return error condition when network connection fails

5 files changed, 516 insertions, 2 deletions

diff --git a/src/library.js b/src/library.js
index 166a015f..b63ac955 100644
--- a/src/library.js
+++ b/src/library.js
@@ -7297,11 +7297,17 @@ LibraryManager.library = {
     // exceptfds not supported
     // timeout is always 0 - fully async
     assert(!exceptfds);
+    
+    var errorCondition = 0;
 
     function canRead(info) {
       // make sure hasData exists. 
       // we do create it when the socket is connected, 
       // but other implementations may create it lazily
+      if ((info.socket.readyState == WebSocket.CLOSING || info.socket.readyState == WebSocket.CLOSED) && info.inQueue.length == 0) {
+        errorCondition = -1;
+        return false;
+      }
       return info.hasData && info.hasData();
     }
 
@@ -7309,6 +7315,10 @@ LibraryManager.library = {
       // make sure socket exists. 
       // we do create it when the socket is connected, 
       // but other implementations may create it lazily
+      if ((info.socket.readyState == WebSocket.CLOSING || info.socket.readyState == WebSocket.CLOSED)) {
+        errorCondition = -1;
+        return false;
+      }
       return info.socket && (info.socket.readyState == info.socket.OPEN);
     }
 
@@ -7340,8 +7350,13 @@ LibraryManager.library = {
       return bitsSet;
     }
 
-    return checkfds(nfds, readfds, canRead)
-         + checkfds(nfds, writefds, canWrite);
+    var totalHandles = checkfds(nfds, readfds, canRead) + checkfds(nfds, writefds, canWrite);
+    if (errorCondition) {
+      ___setErrNo(ERRNO_CODES.EBADF);
+      return -1;
+    } else {
+      return totalHandles;
+    }
   },
 
   // pty.h
diff --git a/tests/runner.py b/tests/runner.py
index b0338855..a3c74f03 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -11862,6 +11862,71 @@ elif 'browser' in str(sys.argv):
       finally:
         self.clean_pids()
 
+    def test_websockets_select_server_down(self):
+      def closedServer(q):
+        import socket
+
+        q.put(None) # No sub-process to start
+        ssock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        ssock.bind(("127.0.0.1", 8994))
+      try:
+        with self.WebsockHarness(8994, closedServer):
+          self.btest('websockets_select.c', expected='266')
+      finally:
+        self.clean_pids()
+
+    def test_websockets_select_server_closes_connection(self):
+      def closingServer(q):
+        import socket
+
+        q.put(None) # No sub-process to start
+        ssock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        ssock.bind(("127.0.0.1", 8994))
+        ssock.listen(2)
+        while True:
+          csock, addr = ssock.accept()
+          print "Connection from %s" % repr(addr)
+          csock.send("1234567")
+          csock.close()
+
+      try:
+        with self.WebsockHarness(8994, closingServer):
+          self.btest('websockets_select_server_closes_connection.c', expected='266')
+      finally:
+        self.clean_pids()
+
+    def test_websockets_select_server_closes_connection_rw(self):
+      def closingServer_rw(q):
+        import socket
+
+        q.put(None) # No sub-process to start
+        ssock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        ssock.bind(("127.0.0.1", 8998))
+        ssock.listen(2)
+        while True:
+          csock, addr = ssock.accept()
+          print "Connection from %s" % repr(addr)
+          readArray = bytearray(10)
+          #readBuffer = buffer(readArray)
+          bytesRead = 0
+          # Let the client start to write data
+          while (bytesRead < 10):
+            (readBytes, address) = csock.recvfrom_into( readArray, 10 )
+            bytesRead += readBytes
+          print "server: 10 bytes read"
+          # Now we write a message on our own ...
+          csock.send("0123456789")
+          print "server: 10 bytes written"
+          # And immediately close the connection
+          csock.close()
+          print "server: connection closed"
+
+      try:
+        with self.WebsockHarness(8998, closingServer_rw):
+          self.btest('websockets_select_server_closes_connection_rw.c', expected='266')
+      finally:
+        self.clean_pids()
+
     def test_enet(self):
       try_delete(self.in_dir('enet'))
       shutil.copytree(path_from_root('tests', 'enet'), self.in_dir('enet'))
diff --git a/tests/websockets_select.c b/tests/websockets_select.c
new file mode 100644
index 00000000..b8ab9091
--- /dev/null
+++ b/tests/websockets_select.c
@@ -0,0 +1,95 @@
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <assert.h>
+#if EMSCRIPTEN
+#include <emscripten.h>
+#endif
+
+#define EXPECTED_BYTES 5
+
+int SocketFD;
+
+int done = 0;
+
+void iter(void *arg) {  
+  fd_set sett;
+  FD_ZERO(&sett);
+  FD_SET(SocketFD, &sett);
+  
+  // The error should happen here
+  int select_says_yes = select(64, &sett, NULL, NULL, NULL);
+  if( select_says_yes == -1 ){
+    printf( "Connection to websocket server failed as expected." );
+    perror( "Error message" );
+    int result = 266;
+    REPORT_RESULT();
+    done = 1;
+  }
+
+  assert(!select_says_yes);
+  done = 1;
+}
+
+// This is for testing a websocket connection to a closed server port.
+// The connect call will succeed (due to the asynchronous websocket
+// behavior) but once the underlying websocket system realized that 
+// the connection cannot be established, the next select call will fail.
+int main(void)
+{
+  struct sockaddr_in stSockAddr;
+  int Res;
+  SocketFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+  if (-1 == SocketFD)
+  {
+    perror("cannot create socket");
+    exit(EXIT_FAILURE);
+  }
+
+  memset(&stSockAddr, 0, sizeof(stSockAddr));
+
+  stSockAddr.sin_family = AF_INET;
+  stSockAddr.sin_port = htons(
+#if EMSCRIPTEN
+    8995
+#else
+    8994
+#endif
+  );
+  Res = inet_pton(AF_INET, "127.0.0.1", &stSockAddr.sin_addr);
+
+  if (0 > Res) {
+    perror("error: first parameter is not a valid address family");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  } else if (0 == Res) {
+    perror("char string (second parameter does not contain valid ipaddress)");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  }
+
+  // This call should succeed (even if the server port is closed)
+  if (-1 == connect(SocketFD, (struct sockaddr *)&stSockAddr, sizeof(stSockAddr))) {
+    perror("connect failed");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+
+  }
+
+#if EMSCRIPTEN
+  emscripten_set_main_loop(iter, 0, 0);
+#else
+  while (!done) iter(NULL);
+#endif
+
+  return EXIT_SUCCESS;
+}
+
diff --git a/tests/websockets_select_server_closes_connection.c b/tests/websockets_select_server_closes_connection.c
new file mode 100644
index 00000000..6ce6d311
--- /dev/null
+++ b/tests/websockets_select_server_closes_connection.c
@@ -0,0 +1,126 @@
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <assert.h>
+#if EMSCRIPTEN
+#include <emscripten.h>
+#endif
+
+#define EXPECTED_BYTES 5
+
+int SocketFD;
+
+int done = 0;
+
+void iter(void *arg) {  
+  static char readbuf[1024];
+  static int readPos = 0;
+  
+  fd_set sett;
+  FD_ZERO(&sett);
+  FD_SET(SocketFD, &sett);
+  
+  if( readPos < 7 ){
+    // still reading
+    int selectRes = select(64, &sett, NULL, NULL, NULL);
+    
+    if( selectRes == 0 )
+      return;
+    
+    if( selectRes == -1 ){
+      perror( "Connection to websocket server failed" );
+      exit(EXIT_FAILURE);
+    }
+    if( selectRes > 0 ){
+      assert(FD_ISSET(SocketFD, &sett));
+      
+      int bytesRead = recv( SocketFD, readbuf+readPos, 7-readPos, 0 );
+      readPos += bytesRead;
+    }
+  } else {
+    // here the server should have closed the connection
+    int selectRes = select(64, &sett, NULL, NULL, NULL);
+    
+    if( selectRes == 0 )
+      return;
+    
+    if( selectRes == -1 ){
+      perror( "Connection to websocket server failed as expected" );
+      int result = 266;
+      REPORT_RESULT();
+      emscripten_cancel_main_loop();
+      done = 1;
+    } 
+    
+    if( selectRes > 0 ){
+      printf( "Error: socket should not show up on select call anymore.\n" );
+      exit(EXIT_FAILURE);
+    }     
+  }
+  
+  return;
+}
+
+// Scenario: the server sends data and closes the connection after 7 bytes. 
+// This test should provoke the situation in which the underlying 
+// tcp connection has been torn down already but there is still data 
+// in the inQueue. The select call has to succeed as long the queue
+// still contains data and only then start to throw errors.
+int main(void)
+{
+  struct sockaddr_in stSockAddr;
+  int Res;
+  SocketFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+  if (-1 == SocketFD)
+  {
+    perror("cannot create socket");
+    exit(EXIT_FAILURE);
+  }
+
+  memset(&stSockAddr, 0, sizeof(stSockAddr));
+
+  stSockAddr.sin_family = AF_INET;
+  stSockAddr.sin_port = htons(
+#if EMSCRIPTEN
+    8995
+#else
+    8994
+#endif
+  );
+  Res = inet_pton(AF_INET, "127.0.0.1", &stSockAddr.sin_addr);
+
+  if (0 > Res) {
+    perror("error: first parameter is not a valid address family");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  } else if (0 == Res) {
+    perror("char string (second parameter does not contain valid ipaddress)");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  }
+
+  // This call should succeed (even if the server port is closed)
+  if (-1 == connect(SocketFD, (struct sockaddr *)&stSockAddr, sizeof(stSockAddr))) {
+    perror("connect failed");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+
+  }
+
+#if EMSCRIPTEN
+  emscripten_set_main_loop(iter, 0, 0);
+#else
+  while (!done) iter(NULL);
+#endif
+
+  return EXIT_SUCCESS;
+}
+
diff --git a/tests/websockets_select_server_closes_connection_rw.c b/tests/websockets_select_server_closes_connection_rw.c
new file mode 100644
index 00000000..dd0913bf
--- /dev/null
+++ b/tests/websockets_select_server_closes_connection_rw.c
@@ -0,0 +1,213 @@
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <assert.h>
+#if EMSCRIPTEN
+#include <emscripten.h>
+#endif
+
+#define EXPECTED_BYTES 5
+
+int SocketFD;
+
+int done = 0;
+
+void iter(void *arg) {
+  static int state = 0;
+  static char writebuf[] = "01234567890123456789";
+  static int writePos = 0;
+  static char readbuf[1024];
+  static int readPos = 0;
+  int selectRes;
+  ssize_t transferAmount;
+  fd_set sett;
+  
+  
+  switch( state ){
+    case 0:
+      // writing 10 bytes to the server
+      
+      // the socket in the read file descriptors has to result in a 0 return value
+      // because the connection exists, but there is no data yet
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, &sett, NULL, NULL, NULL);
+      if( selectRes != 0 ){
+        printf( "case 0: read select != 0\n" );
+        exit(EXIT_FAILURE);
+      }
+      
+      // the socket in the write file descriptors has to result in either a 0 or 1
+      // the connection either is setting up or is established and writing is possible
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, NULL, &sett, NULL, NULL);
+      if( selectRes == -1 ){
+        printf( "case 0: write select == -1\n" );
+        exit(EXIT_FAILURE);
+      }
+      if( selectRes == 0 ){
+        return;
+      }
+      
+      // send a single byte
+      transferAmount = send( SocketFD, writebuf+writePos, 1, 0 );
+      writePos += transferAmount;
+   
+      // after 10 bytes switch to next state
+      if( writePos >= 10 ){
+        state = 1;
+      }
+      break;
+      
+    case 1:
+      // wait until we can read one byte to make sure the server
+      // has sent the data and then closed the connection
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, &sett, NULL, NULL, NULL);
+      if( selectRes == -1 ){
+        printf( "case 1: read selectRes == -1\n" );
+        exit(EXIT_FAILURE);
+      }
+      if( selectRes == 0 )
+        return;
+
+      // read a single byte
+      transferAmount = recv( SocketFD, readbuf+readPos, 1, 0 );
+      readPos += transferAmount;
+   
+      // if successfully reading 1 byte, switch to next state
+      if( readPos >= 1 ){
+        state = 2;
+      }
+      break;
+    
+    case 2:
+      // calling select with the socket in the write file descriptors has
+      // to fail because the tcp network connection is already down
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, NULL, &sett, NULL, NULL);
+      if( selectRes != -1 ){
+        printf( "case 2: write selectRes != -1\n" );
+        exit(EXIT_FAILURE);
+      }
+
+      // calling select with the socket in the read file descriptors 
+      // has to succeed because there is still data in the inQueue
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, &sett, NULL, NULL, NULL);
+      if( selectRes != 1 ){
+        printf( "case 2: read selectRes != 1\n" );
+        exit(EXIT_FAILURE);
+      }
+      if( selectRes == 0 )
+        return;
+      
+      // read a single byte
+      transferAmount = recv( SocketFD, readbuf+readPos, 1, 0 );
+      readPos += transferAmount;
+      
+      // with 10 bytes read the inQueue is empty => switch state
+      if( readPos >= 10 ){
+        state = 3;
+      }
+      break;
+      
+    case 3:
+      // calling select with the socket in the read file descriptors 
+      // now also has to fail as the inQueue is empty
+      FD_ZERO( &sett );
+      FD_SET(SocketFD, &sett);
+      selectRes = select(64, &sett, NULL, NULL, NULL);
+      if( selectRes != -1 ){
+        printf( "case 3: read selectRes != -1\n" );
+        exit(EXIT_FAILURE);
+      }
+      
+      // report back success, the 266 is just an arbitrary value without 
+      // deeper meaning
+      int result = 266;
+      REPORT_RESULT();
+      break;
+      
+    default:
+      printf( "Impossible state!\n" );
+      exit(EXIT_FAILURE);
+      break;
+  }
+  
+  return;
+}
+
+// This test checks for an intended asymmetry in the behavior of the select function.
+// Scenario: the client sends data to the server. After 10 received bytes the 
+// server sends 10 bytes on its own and immediately afterwards closes the connection.
+// This mimics a typical connect-request-response-disconnect situation.
+// After the server closed the connection select calls with the socket in the write file 
+// descriptors have to fail as the tcp connection is already down and there is no way 
+// anymore to send data. 
+// Select calls with the socket in the read file descriptor list still have to succeed 
+// as there are still 10 bytes to read from the inQueue. So, for the same socket the 
+// select call behaves differently depending on whether the socket is listed in the
+// read or write file descriptors.
+int main(void)
+{
+  struct sockaddr_in stSockAddr;
+  int Res;
+  SocketFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+
+  if (-1 == SocketFD)
+  {
+    perror("cannot create socket");
+    exit(EXIT_FAILURE);
+  }
+
+  memset(&stSockAddr, 0, sizeof(stSockAddr));
+
+  stSockAddr.sin_family = AF_INET;
+  stSockAddr.sin_port = htons(
+#if EMSCRIPTEN
+    8999
+#else
+    8998
+#endif
+  );
+  Res = inet_pton(AF_INET, "127.0.0.1", &stSockAddr.sin_addr);
+
+  if (0 > Res) {
+    perror("error: first parameter is not a valid address family");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  } else if (0 == Res) {
+    perror("char string (second parameter does not contain valid ipaddress)");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+  }
+
+  // This call should succeed (even if the server port is closed)
+  if (-1 == connect(SocketFD, (struct sockaddr *)&stSockAddr, sizeof(stSockAddr))) {
+    perror("connect failed");
+    close(SocketFD);
+    exit(EXIT_FAILURE);
+
+  }
+
+#if EMSCRIPTEN
+  emscripten_set_main_loop(iter, 0, 0);
+#else
+  while (!done) iter(NULL);
+#endif
+
+  return EXIT_SUCCESS;
+}
+