sendrecv: split the I/O handling into private handler

Howard Chu brought the bulk work of this patch that properly
moves out the sending and recving of data to the parts of the
code that are properly responsible for the various ways of doing
so.

Daniel Stenberg assisted with polishing a few bits and fixed some
minor flaws in the original patch.

Another upside of this patch is that we now abuse CURLcodes less
with the "magic" -1 return codes and instead use CURLE_AGAIN more
consistently.

1 files changed, 34 insertions, 12 deletions

diff --git a/lib/ssh.c b/lib/ssh.c
index e4e5767c7..4a9309998 100644
--- a/lib/ssh.c
+++ b/lib/ssh.c
@@ -2464,6 +2464,9 @@ static CURLcode ssh_init(struct connectdata *conn)
   return CURLE_OK;
 }
 
+static Curl_recv scp_recv, sftp_recv;
+static Curl_send scp_send, sftp_send;
+
 /*
  * Curl_ssh_connect() gets called from Curl_protocol_connect() to allow us to
  * do protocol-specific actions at connect-time.
@@ -2489,6 +2492,13 @@ static CURLcode ssh_connect(struct connectdata *conn, bool *done)
   if(result)
     return result;
 
+  if(conn->protocol & PROT_SCP) {
+    conn->recv = scp_recv;
+    conn->send = scp_send;
+  } else {
+    conn->recv = sftp_recv;
+    conn->send = sftp_send;
+  }
   ssh = &conn->proto.sshc;
 
 #ifdef CURL_LIBSSH2_DEBUG
@@ -2703,8 +2713,8 @@ static CURLcode scp_done(struct connectdata *conn, CURLcode status,
 }
 
 /* return number of received (decrypted) bytes */
-ssize_t Curl_scp_send(struct connectdata *conn, int sockindex,
-                      const void *mem, size_t len)
+static ssize_t scp_send(struct connectdata *conn, int sockindex,
+                        const void *mem, size_t len, CURLcode *err)
 {
   ssize_t nwrite;
   (void)sockindex; /* we only support SCP on the fixed known primary socket */
@@ -2715,8 +2725,10 @@ ssize_t Curl_scp_send(struct connectdata *conn, int sockindex,
 
   ssh_block2waitfor(conn, (nwrite == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);
 
-  if(nwrite == LIBSSH2_ERROR_EAGAIN)
-    return 0;
+  if(nwrite == LIBSSH2_ERROR_EAGAIN) {
+    *err = CURLE_AGAIN;
+    nwrite = 0;
+  }
 
   return nwrite;
 }
@@ -2725,8 +2737,8 @@ ssize_t Curl_scp_send(struct connectdata *conn, int sockindex,
  * If the read would block (EWOULDBLOCK) we return -1. Otherwise we return
  * a regular CURLcode value.
  */
-ssize_t Curl_scp_recv(struct connectdata *conn, int sockindex,
-                      char *mem, size_t len)
+static ssize_t scp_recv(struct connectdata *conn, int sockindex,
+                        char *mem, size_t len, CURLcode *err)
 {
   ssize_t nread;
   (void)sockindex; /* we only support SCP on the fixed known primary socket */
@@ -2736,6 +2748,10 @@ ssize_t Curl_scp_recv(struct connectdata *conn, int sockindex,
     libssh2_channel_read(conn->proto.sshc.ssh_channel, mem, len);
 
   ssh_block2waitfor(conn, (nread == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);
+  if (nread == LIBSSH2_ERROR_EAGAIN) {
+    *err = CURLE_AGAIN;
+    nread = -1;
+  }
 
   return nread;
 }
@@ -2840,8 +2856,8 @@ static CURLcode sftp_done(struct connectdata *conn, CURLcode status,
 }
 
 /* return number of sent bytes */
-ssize_t Curl_sftp_send(struct connectdata *conn, int sockindex,
-                       const void *mem, size_t len)
+static ssize_t sftp_send(struct connectdata *conn, int sockindex,
+                         const void *mem, size_t len, CURLcode *err)
 {
   ssize_t nwrite;   /* libssh2_sftp_write() used to return size_t in 0.14
                        but is changed to ssize_t in 0.15. These days we don't
@@ -2852,8 +2868,10 @@ ssize_t Curl_sftp_send(struct connectdata *conn, int sockindex,
 
   ssh_block2waitfor(conn, (nwrite == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);
 
-  if(nwrite == LIBSSH2_ERROR_EAGAIN)
-    return 0;
+  if(nwrite == LIBSSH2_ERROR_EAGAIN) {
+    *err = CURLE_AGAIN;
+    nwrite = 0;
+  }
 
   return nwrite;
 }
@@ -2861,8 +2879,8 @@ ssize_t Curl_sftp_send(struct connectdata *conn, int sockindex,
 /*
  * Return number of received (decrypted) bytes
  */
-ssize_t Curl_sftp_recv(struct connectdata *conn, int sockindex,
-                       char *mem, size_t len)
+static ssize_t sftp_recv(struct connectdata *conn, int sockindex,
+                         char *mem, size_t len, CURLcode *err)
 {
   ssize_t nread;
   (void)sockindex;
@@ -2871,6 +2889,10 @@ ssize_t Curl_sftp_recv(struct connectdata *conn, int sockindex,
 
   ssh_block2waitfor(conn, (nread == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);
 
+  if(nread == LIBSSH2_ERROR_EAGAIN) {
+    *err = CURLE_AGAIN;
+    nread = -1;
+  }
   return nread;
 }