_libssh2_channel_write: removed 32500 size limit

Neither _libssh2_channel_write nor sftp_write now have the 32500 size
limit anymore and instead the channel writing function now has its own
logic to send data in multiple calls until everything is sent.

src/channel.c

@@ -1969,7 +1969,7 @@ _libssh2_channel_packet_data_len(LIBSSH2_CHANNEL * channel, int stream_id)
 }
 
 /*
- * _libssh2_channel_write
+ * channel_write
  *
  * Send data to a channel. Note that if this returns EAGAIN, the caller must
  * call this function again with the SAME input arguments.
@@ -1977,8 +1977,8 @@ _libssh2_channel_packet_data_len(LIBSSH2_CHANNEL * channel, int stream_id)
  * Returns: number of bytes sent, or if it returns a negative number, that is
  * the error code!
  */
-ssize_t
-_libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
+static ssize_t
+channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
               const unsigned char *buf, size_t buflen)
 {
     LIBSSH2_SESSION *session = channel->session;
@@ -2103,6 +2103,73 @@ _libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
     return LIBSSH2_ERROR_INVAL; /* reaching this point is really bad */
 }
 
+/*
+ * _libssh2_channel_write
+ *
+ * Send data to a channel. Note that if this returns EAGAIN, the caller must
+ * call this function again with the SAME input arguments.
+ *
+ * Returns: number of bytes sent, or if it returns a negative number, that is
+ * the error code!
+ */
+ssize_t
+_libssh2_channel_write(LIBSSH2_CHANNEL *channel, int stream_id,
+                       const unsigned char *buf, size_t buflen)
+{
+    LIBSSH2_SESSION *session = channel->session;
+    int rc = 0;
+    ssize_t wrote = 0;
+
+    if(channel->transport_buf) {
+        /* previous EAGAIN situation, take care of this first */
+        rc = channel_write(channel,
+                           channel->transport_streamid,
+                           channel->transport_buf,
+                           channel->transport_buflen);
+        if(rc == LIBSSH2_ERROR_EAGAIN)
+            /* still EAGAIN, get out */
+            return rc;
+        else if(rc < 0)
+            return rc;
+
+        if(rc != channel->transport_buflen) {
+            /* previous buffer not drained yet */
+            channel->transport_buf += rc;
+            channel->transport_buflen -= rc;
+            return LIBSSH2_ERROR_EAGAIN;
+        }
+
+        /* all is sent, clear the buf pointer */
+        channel->transport_buf = NULL;
+    }
+
+    do {
+        rc = channel_write(channel, stream_id, buf, buflen);
+
+        if(rc < 0) {
+            if(rc == LIBSSH2_ERROR_EAGAIN) {
+                /* store the buf/buflen pair and use that in the next call
+                   again to flush the transport layer */
+                channel->transport_streamid = stream_id;
+                channel->transport_buf = buf;
+                channel->transport_buflen = buflen;
+                if(wrote)
+                    return wrote;
+
+                /* nothing written, return EAGAIN */
+                return rc;
+            }
+            return rc;
+        }
+        wrote += rc;
+        buf += rc;
+        buflen -= rc;
+
+    } while(buflen);
+
+    return wrote;
+}
+
 /*
  * libssh2_channel_write_ex
  *

src/libssh2_priv.h

@@ -401,6 +401,10 @@ struct _LIBSSH2_CHANNEL
     size_t write_packet_len;
     size_t write_bufwrite;
 
+    int transport_streamid;
+    const unsigned char *transport_buf;
+    size_t transport_buflen;
+
     /* State variables used in libssh2_channel_close() */
     libssh2_nonblocking_states close_state;
     unsigned char close_packet[5];
@@ -416,6 +420,7 @@ struct _LIBSSH2_CHANNEL
 
     /* State variables used in libssh2_channel_handle_extended_data2() */
     libssh2_nonblocking_states extData2_state;
+
 };
 
 struct _LIBSSH2_LISTENER

src/sftp.c

@@ -1400,10 +1400,6 @@ static ssize_t sftp_write(LIBSSH2_SFTP_HANDLE *handle, const char *buffer,
     unsigned char *s, *data;
     int rc;
 
-    /* we limit this to just send a single SSH packet at a time */
-    if(count > 32500)
-        count = 32500;
-
     packet_len = handle->handle_len + count + 25;
 
     if (sftp->write_state == libssh2_NB_state_idle) {