From 862b02f8947039e9a7f5d6ae47b547e3bf295988 Mon Sep 17 00:00:00 2001
From: Richard Hsu <richardhsu.cs@gmail.com>
Date: Tue, 4 Apr 2017 19:26:29 -0700
Subject: [PATCH] Telnet: Write full buffer instead of byte-by-byte

Previous TODO wanting to write in chunks. We should support writing more
at once since some TELNET servers may respond immediately upon first
byte written such as WHOIS servers.

Closes #1389
---
 lib/telnet.c            | 80 +++++++++++++++++++++++++----------------
 tests/data/Makefile.inc |  2 +-
 tests/data/test1399     | 43 ++++++++++++++++++++++
 3 files changed, 94 insertions(+), 31 deletions(-)
 create mode 100644 tests/data/test1399

diff --git a/lib/telnet.c b/lib/telnet.c
index dd93f3530..155d4b260 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -1220,43 +1220,63 @@ CURLcode telrcv(struct connectdata *conn,
 }
 
 /* Escape and send a telnet data block */
-/* TODO: write large chunks of data instead of one byte at a time */
 static CURLcode send_telnet_data(struct connectdata *conn,
                                  char *buffer, ssize_t nread)
 {
-  unsigned char outbuf[2];
-  ssize_t bytes_written, total_written;
-  int out_count;
+  ssize_t escapes, i, j, outlen;
+  unsigned char *outbuf = NULL;
   CURLcode result = CURLE_OK;
+  ssize_t bytes_written, total_written;
 
-  while(!result && nread--) {
-    outbuf[0] = *buffer++;
-    out_count = 1;
-    if(outbuf[0] == CURL_IAC)
-      outbuf[out_count++] = CURL_IAC;
+  /* Determine size of new buffer after escaping */
+  escapes = 0;
+  for(i = 0; i < nread; i++)
+    if((unsigned char)buffer[i] == CURL_IAC)
+      escapes++;
+  outlen = nread + escapes;
 
-    total_written = 0;
-    do {
-      /* Make sure socket is writable to avoid EWOULDBLOCK condition */
-      struct pollfd pfd[1];
-      pfd[0].fd = conn->sock[FIRSTSOCKET];
-      pfd[0].events = POLLOUT;
-      switch(Curl_poll(pfd, 1, -1)) {
-        case -1:                    /* error, abort writing */
-        case 0:                     /* timeout (will never happen) */
-          result = CURLE_SEND_ERROR;
-          break;
-        default:                    /* write! */
-          bytes_written = 0;
-          result = Curl_write(conn, conn->sock[FIRSTSOCKET],
-                              outbuf+total_written, out_count-total_written,
-                              &bytes_written);
-          total_written += bytes_written;
-          break;
-      }
-      /* handle partial write */
-    } while(!result && total_written < out_count);
+  if(outlen == nread)
+    outbuf = (unsigned char *)buffer;
+  else {
+    outbuf = malloc(nread + escapes + 1);
+    if(!outbuf)
+      return CURLE_OUT_OF_MEMORY;
+
+    j = 0;
+    for(i = 0; i < nread; i++) {
+      outbuf[j++] = buffer[i];
+      if((unsigned char)buffer[i] == CURL_IAC)
+        outbuf[j++] = CURL_IAC;
+    }
+    outbuf[j] = '\0';
   }
+
+  total_written = 0;
+  while(!result && total_written < outlen) {
+    /* Make sure socket is writable to avoid EWOULDBLOCK condition */
+    struct pollfd pfd[1];
+    pfd[0].fd = conn->sock[FIRSTSOCKET];
+    pfd[0].events = POLLOUT;
+    switch(Curl_poll(pfd, 1, -1)) {
+      case -1:                    /* error, abort writing */
+      case 0:                     /* timeout (will never happen) */
+        result = CURLE_SEND_ERROR;
+        break;
+      default:                    /* write! */
+        bytes_written = 0;
+        result = Curl_write(conn, conn->sock[FIRSTSOCKET],
+                            outbuf + total_written,
+                            outlen - total_written,
+                            &bytes_written);
+        total_written += bytes_written;
+        break;
+    }
+  }
+
+  /* Free malloc copy if escaped */
+  if(outbuf != (unsigned char *)buffer)
+    free(outbuf);
+
   return result;
 }
 
diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 9e573f6aa..94439bccd 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -146,7 +146,7 @@ test1364 test1365 test1366 test1367 test1368 test1369 test1370 test1371 \
 test1372 test1373 test1374 test1375 test1376 test1377 test1378 test1379 \
 test1380 test1381 test1382 test1383 test1384 test1385 test1386 test1387 \
 test1388 test1389 test1390 test1391 test1392 test1393 test1394 test1395 \
-test1396 test1397 test1398 \
+test1396 test1397 test1398 test1399 \
 \
 test1400 test1401 test1402 test1403 test1404 test1405 test1406 test1407 \
 test1408 test1409 test1410 test1411 test1412 test1413 test1414 test1415 \
diff --git a/tests/data/test1399 b/tests/data/test1399
new file mode 100644
index 000000000..830960532
--- /dev/null
+++ b/tests/data/test1399
@@ -0,0 +1,43 @@
+<testcase>
+<info>
+<keywords>
+TELNET
+UPLOAD
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<features>
+telnet
+</features>
+<name>
+TELNET check stdin to HTTP
+</name>
+<stdin>
+GET /we/want/1399 HTTP/1.0
+
+</stdin>
+<command option="no-output">
+telnet://%HOSTIP:%HTTPPORT
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+GET /we/want/1399 HTTP/1.0
+
+</protocol>
+</verify>
+</testcase>