all reads from stdin and writes to stdout will be retried until the

whole operation completes or an unrecoverable condition is detected

tests/server/sockfilt.c

@@ -98,6 +98,7 @@ static volatile int sigpipe;  /* Why? It's not used */
 
 const char *serverlogfile = (char *)DEFAULT_LOGFILE;
 
+bool verbose = FALSE;
 bool use_ipv6 = FALSE;
 unsigned short port = DEFAULT_PORT;
 unsigned short connectport = 0; /* if non-zero, we activate this mode */
@@ -109,6 +110,118 @@ enum sockmode {
   ACTIVE_DISCONNECT  /* as a client, disconnected from server */
 };
 
+/*
+ * fullread is a wrapper around the read() function. This will repeat the call
+ * to read() until it actually has read the complete number of bytes indicated
+ * in nbytes or it fails with a condition that cannot be handled with a simple
+ * retry of the read call.
+ */
+
+static ssize_t fullread(int filedes, void *buffer, size_t nbytes)
+{
+  int error;
+  ssize_t rc;
+  ssize_t nread = 0;
+
+  do {
+    rc = read(filedes, (unsigned char *)buffer + nread, nbytes - nread);
+
+    if(rc < 0) {
+      error = ERRNO;
+      if((error == EINTR) || (error == EAGAIN))
+        continue;
+      logmsg("unrecoverable read() failure: %s", strerror(error));
+      return -1;
+    }
+
+    if(rc == 0) {
+      logmsg("got 0 reading from stdin");
+      return 0;
+    }
+
+    nread += rc;
+
+  } while((size_t)nread < nbytes);
+
+  if(verbose)
+    logmsg("read %ld bytes", (long)nread);
+
+  return nread;
+}
+
+/*
+ * fullwrite is a wrapper around the write() function. This will repeat the
+ * call to write() until it actually has written the complete number of bytes
+ * indicated in nbytes or it fails with a condition that cannot be handled
+ * with a simple retry of the write call.
+ */
+
+static ssize_t fullwrite(int filedes, const void *buffer, size_t nbytes)
+{
+  int error;
+  ssize_t wc;
+  ssize_t nwrite = 0;
+
+  do {
+    wc = write(filedes, (unsigned char *)buffer + nwrite, nbytes - nwrite);
+
+    if(wc < 0) {
+      error = ERRNO;
+      if((error == EINTR) || (error == EAGAIN))
+        continue;
+      logmsg("unrecoverable write() failure: %s", strerror(error));
+      return -1;
+    }
+
+    if(wc == 0) {
+      logmsg("put 0 writing to stdout");
+      return 0;
+    }
+
+    nwrite += wc;
+
+  } while((size_t)nwrite < nbytes);
+
+  if(verbose)
+    logmsg("wrote %ld bytes", (long)nwrite);
+
+  return nwrite;
+}
+
+/*
+ * read_stdin tries to read from stdin nbytes into the given buffer. This is a
+ * blocking function that will only return TRUE when nbytes have actually been
+ * read or FALSE when an unrecoverable error has been detected. Failure of this
+ * function is an indication that the whole program should terminate.
+ */
+
+static bool read_stdin(void *buffer, size_t nbytes)
+{
+  ssize_t nread = fullread(fileno(stdin), buffer, nbytes);
+  if(nread != (ssize_t)nbytes) {
+    logmsg("exiting...");
+    return FALSE;
+  }
+  return TRUE;
+}
+
+/*
+ * write_stdout tries to write to stdio nbytes from the given buffer. This is a
+ * blocking function that will only return TRUE when nbytes have actually been
+ * written or FALSE when an unrecoverable error has been detected. Failure of
+ * this function is an indication that the whole program should terminate.
+ */
+
+static bool write_stdout(const void *buffer, size_t nbytes)
+{
+  ssize_t nwrite = fullwrite(fileno(stdout), buffer, nbytes);
+  if(nwrite != (ssize_t)nbytes) {
+    logmsg("exiting...");
+    return FALSE;
+  }
+  return TRUE;
+}
+
 static void lograw(unsigned char *buffer, ssize_t len)
 {
   char data[120];
@@ -171,7 +284,6 @@ static bool juggle(curl_socket_t *sockfdp,
   curl_socket_t sockfd;
   curl_socket_t maxfd;
   ssize_t rc;
-  ssize_t nread_stdin;
   ssize_t nread_socket;
   ssize_t bytes_written;
   ssize_t buffer_len;
@@ -184,8 +296,10 @@ static bool juggle(curl_socket_t *sockfdp,
 #ifdef HAVE_GETPPID
   /* As a last resort, quit if sockfilt process becomes orphan. Just in case
      parent ftpserver process has died without killing its sockfilt children */
-  if(getppid() <= 1)
+  if(getppid() <= 1) {
+    logmsg("process becomes orphan, exiting");
     return FALSE;
+  }
 #endif
 
   timeout.tv_sec = 120;
@@ -246,17 +360,19 @@ static bool juggle(curl_socket_t *sockfdp,
 
   } /* switch(*mode) */
 
+
   do {
-    rc = select(maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout);
+
+    rc = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout);
+
   } while((rc == -1) && (SOCKERRNO == EINTR));
 
-  switch(rc) {
+  if(rc < 0)
-  case -1:
     return FALSE;
 
-  case 0: /* timeout! */
+  if(rc == 0)
+    /* timeout */
     return TRUE;
-  }
 
 
   if(FD_ISSET(fileno(stdin), &fds_read)) {
@@ -274,96 +390,86 @@ static bool juggle(curl_socket_t *sockfdp,
 
        DATA - plain pass-thru data
     */
-    nread_stdin = read(fileno(stdin), buffer, 5);
-    if(5 == nread_stdin) {
 
-      logmsg("Received %c%c%c%c (on stdin)",
+    if(!read_stdin(buffer, 5))
-             buffer[0], buffer[1], buffer[2], buffer[3] );
+      return FALSE;
 
-      if(!memcmp("PING", buffer, 4)) {
+    logmsg("Received %c%c%c%c (on stdin)",
-        /* send reply on stdout, just proving we are alive */
+           buffer[0], buffer[1], buffer[2], buffer[3] );
-        write(fileno(stdout), "PONG\n", 5);
-      }
 
-      else if(!memcmp("PORT", buffer, 4)) {
+    if(!memcmp("PING", buffer, 4)) {
-        /* Question asking us what PORT number we are listening to.
+      /* send reply on stdout, just proving we are alive */
-           Replies to PORT with "IPv[num]/[port]" */
+      if(!write_stdout("PONG\n", 5))
-        sprintf((char *)buffer, "IPv%d/%d\n", use_ipv6?6:4, (int)port);
+        return FALSE;
-        buffer_len = (ssize_t)strlen((char *)buffer);
+    }
-        snprintf(data, sizeof(data), "PORT\n%04x\n", buffer_len);
+
-        write(fileno(stdout), data, 10);
+    else if(!memcmp("PORT", buffer, 4)) {
-        write(fileno(stdout), buffer, buffer_len);
+      /* Question asking us what PORT number we are listening to.
-      }
+         Replies to PORT with "IPv[num]/[port]" */
-      else if(!memcmp("QUIT", buffer, 4)) {
+      sprintf((char *)buffer, "IPv%d/%d\n", use_ipv6?6:4, (int)port);
-        /* just die */
+      buffer_len = (ssize_t)strlen((char *)buffer);
-        logmsg("quits");
+      snprintf(data, sizeof(data), "PORT\n%04x\n", buffer_len);
+      if(!write_stdout(data, 10))
+        return FALSE;
+      if(!write_stdout(buffer, buffer_len))
+        return FALSE;
+    }
+    else if(!memcmp("QUIT", buffer, 4)) {
+      /* just die */
+      logmsg("quits");
+      return FALSE;
+    }
+    else if(!memcmp("DATA", buffer, 4)) {
+      /* data IN => data OUT */
+
+      if(!read_stdin(buffer, 5))
+        return FALSE;
+
+      buffer[5] = '\0';
+
+      buffer_len = (ssize_t)strtol((char *)buffer, NULL, 16);
+      if (buffer_len > (ssize_t)sizeof(buffer)) {
+        logmsg("ERROR: Buffer size (%ld bytes) too small for data size "
+               "(%ld bytes)", (long)sizeof(buffer), (long)buffer_len);
         return FALSE;
       }
-      else if(!memcmp("DATA", buffer, 4)) {
+      logmsg("> %d bytes data, server => client", buffer_len);
-        /* data IN => data OUT */
 
-        if(5 != read(fileno(stdin), buffer, 5))
+      if(!read_stdin(buffer, buffer_len))
+        return FALSE;
+
+      lograw(buffer, buffer_len);
+
+      if(*mode == PASSIVE_LISTEN) {
+        logmsg("*** We are disconnected!");
+        if(!write_stdout("DISC\n", 5))
           return FALSE;
-        buffer[5] = '\0';
-
-        buffer_len = (ssize_t)strtol((char *)buffer, NULL, 16);
-        if (buffer_len > (ssize_t)sizeof(buffer)) {
-          logmsg("ERROR: Buffer size (%ld bytes) too small for data size "
-                 "(%ld bytes)", (long)sizeof(buffer), (long)buffer_len);
-          return FALSE;
-        }
-        logmsg("> %d bytes data, server => client", buffer_len);
-
-        /*
-         * To properly support huge data chunks, we need to repeat the call
-         * to read() until we're done or it fails.
-         */
-        nread_stdin = 0;
-        do {
-          /* get data in the buffer at the correct position */
-          rc = read(fileno(stdin), &buffer[nread_stdin],
-                    buffer_len - nread_stdin);
-          logmsg("read %d bytes", rc);
-          if(rc <= 0)
-            return FALSE;
-          nread_stdin += rc;
-        } while (nread_stdin < buffer_len);
-
-        lograw(buffer, buffer_len);
-
-        if(*mode == PASSIVE_LISTEN) {
-          logmsg("*** We are disconnected!");
-          write(fileno(stdout), "DISC\n", 5);
-        }
-        else {
-          /* send away on the socket */
-          bytes_written = swrite(sockfd, buffer, buffer_len);
-          if(bytes_written != buffer_len) {
-            logmsg("Not all data was sent. Bytes to send: %d sent: %d", 
-                   buffer_len, bytes_written);
-          }
-        }
       }
-      else if(!memcmp("DISC", buffer, 4)) {
+      else {
-        /* disconnect! */
+        /* send away on the socket */
-        write(fileno(stdout), "DISC\n", 5);
+        bytes_written = swrite(sockfd, buffer, buffer_len);
-        if(sockfd != CURL_SOCKET_BAD) {
+        if(bytes_written != buffer_len) {
-          logmsg("====> Client forcibly disconnected");
+          logmsg("Not all data was sent. Bytes to send: %d sent: %d", 
-          sclose(sockfd);
+                 buffer_len, bytes_written);
-          *sockfdp = CURL_SOCKET_BAD;
-          if(*mode == PASSIVE_CONNECT)
-            *mode = PASSIVE_LISTEN;
-          else
-            *mode = ACTIVE_DISCONNECT;
         }
-        else
-          logmsg("attempt to close already dead connection");
-        return TRUE;
       }
     }
-    else if(-1 == nread_stdin) {
+    else if(!memcmp("DISC", buffer, 4)) {
-      logmsg("read %d from stdin, exiting", nread_stdin);
+      /* disconnect! */
-      return FALSE;
+      if(!write_stdout("DISC\n", 5))
+        return FALSE;
+      if(sockfd != CURL_SOCKET_BAD) {
+        logmsg("====> Client forcibly disconnected");
+        sclose(sockfd);
+        *sockfdp = CURL_SOCKET_BAD;
+        if(*mode == PASSIVE_CONNECT)
+          *mode = PASSIVE_LISTEN;
+        else
+          *mode = ACTIVE_DISCONNECT;
+      }
+      else
+        logmsg("attempt to close already dead connection");
+      return TRUE;
     }
   }
 
@@ -378,7 +484,8 @@ static bool juggle(curl_socket_t *sockfdp,
         logmsg("accept() failed");
       else {
         logmsg("====> Client connect");
-        write(fileno(stdout), "CNCT\n", 5);
+        if(!write_stdout("CNCT\n", 5))
+          return FALSE;
         *sockfdp = sockfd; /* store the new socket */
         *mode = PASSIVE_CONNECT; /* we have connected */
       }
@@ -390,7 +497,8 @@ static bool juggle(curl_socket_t *sockfdp,
 
     if(nread_socket <= 0) {
       logmsg("====> Client disconnect");
-      write(fileno(stdout), "DISC\n", 5);
+      if(!write_stdout("DISC\n", 5))
+        return FALSE;
       sclose(sockfd);
       *sockfdp = CURL_SOCKET_BAD;
       if(*mode == PASSIVE_CONNECT)
@@ -401,8 +509,10 @@ static bool juggle(curl_socket_t *sockfdp,
     }
 
     snprintf(data, sizeof(data), "DATA\n%04x\n", nread_socket);
-    write(fileno(stdout), data, 10);
+    if(!write_stdout(data, 10))
-    write(fileno(stdout), buffer, nread_socket);
+      return FALSE;
+    if(!write_stdout(buffer, nread_socket))
+      return FALSE;
 
     logmsg("< %d bytes data, client => server", nread_socket);
     lograw(buffer, nread_socket);
@@ -537,6 +647,10 @@ int main(int argc, char *argv[])
              );
       return 0;
     }
+    else if(!strcmp("--verbose", argv[arg])) {
+      verbose = TRUE;
+      arg++;
+    }
     else if(!strcmp("--pidfile", argv[arg])) {
       arg++;
       if(argc>arg)
@@ -585,6 +699,7 @@ int main(int argc, char *argv[])
     else {
       puts("Usage: sockfilt [option]\n"
            " --version\n"
+           " --verbose\n"
            " --logfile [file]\n"
            " --pidfile [file]\n"
            " --ipv4\n"
@@ -689,7 +804,9 @@ int main(int argc, char *argv[])
   while(juggle(&msgsock, sock, &mode));
 
   sclose(sock);
+  unlink(pidname);
 
+  logmsg("sockfilt exits");
   return 0;
 }