libssh: added SFTP support

The SFTP back-end supports asynchronous reading only, limited
to 32-bit file length. Writing is synchronous with no other
limitations.

This also brings keyboard-interactive authentication.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>

1 files changed, 1527 insertions, 14 deletions

diff --git a/lib/ssh-libssh.c b/lib/ssh-libssh.c
index 6c05f6d2d..732aad7fa 100644
--- a/lib/ssh-libssh.c
+++ b/lib/ssh-libssh.c
@@ -7,7 +7,8 @@
  *
  * Copyright (C) 2017 Red Hat, Inc.
  *
- * Authors: Nikos Mavrogiannopoulos, Tomas Mraz, Stanislav Zidek, Robert Kolcun
+ * Authors: Nikos Mavrogiannopoulos, Tomas Mraz, Stanislav Zidek,
+ *          Robert Kolcun, Andreas Schneider
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -31,6 +32,7 @@
 #endif
 
 #include <libssh/libssh.h>
+#include <libssh/sftp.h>
 
 #ifdef HAVE_FCNTL_H
 #include <fcntl.h>
@@ -83,6 +85,12 @@
 #include "select.h"
 #include "warnless.h"
 
+/* for permission and open flags */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+
 /* The last 3 #include files should be in this order */
 #include "curl_printf.h"
 #include "curl_memory.h"
@@ -101,6 +109,19 @@ static CURLcode scp_doing(struct connectdata *conn, bool *dophase_done);
 static CURLcode scp_disconnect(struct connectdata *conn,
                                bool dead_connection);
 
+static CURLcode sftp_done(struct connectdata *conn,
+                          CURLcode, bool premature);
+static CURLcode sftp_doing(struct connectdata *conn,
+                           bool *dophase_done);
+static CURLcode sftp_disconnect(struct connectdata *conn, bool dead);
+static
+CURLcode sftp_perform(struct connectdata *conn,
+                      bool *connected,
+                      bool *dophase_done);
+
+static void sftp_quote(struct connectdata *conn);
+static void sftp_quote_stat(struct connectdata *conn);
+
 static int myssh_getsock(struct connectdata *conn, curl_socket_t *sock,
                          int numsocks);
 
@@ -136,6 +157,56 @@ const struct Curl_handler Curl_handler_scp = {
 };
 
 /*
+ * SFTP protocol handler.
+ */
+
+const struct Curl_handler Curl_handler_sftp = {
+  "SFTP",                               /* scheme */
+  myssh_setup_connection,               /* setup_connection */
+  myssh_do_it,                          /* do_it */
+  sftp_done,                            /* done */
+  ZERO_NULL,                            /* do_more */
+  myssh_connect,                        /* connect_it */
+  myssh_multi_statemach,                /* connecting */
+  sftp_doing,                           /* doing */
+  myssh_getsock,                        /* proto_getsock */
+  myssh_getsock,                        /* doing_getsock */
+  ZERO_NULL,                            /* domore_getsock */
+  myssh_perform_getsock,                /* perform_getsock */
+  sftp_disconnect,                      /* disconnect */
+  ZERO_NULL,                            /* readwrite */
+  ZERO_NULL,                            /* connection_check */
+  PORT_SSH,                             /* defport */
+  CURLPROTO_SFTP,                       /* protocol */
+  PROTOPT_DIRLOCK | PROTOPT_CLOSEACTION
+  | PROTOPT_NOURLQUERY                  /* flags */
+};
+
+static CURLcode sftp_error_to_CURLE(int err)
+{
+  switch(err) {
+    case SSH_FX_OK:
+      return CURLE_OK;
+
+    case SSH_FX_NO_SUCH_FILE:
+    case SSH_FX_NO_SUCH_PATH:
+      return CURLE_REMOTE_FILE_NOT_FOUND;
+
+    case SSH_FX_PERMISSION_DENIED:
+    case SSH_FX_WRITE_PROTECT:
+      return CURLE_REMOTE_ACCESS_DENIED;
+
+    case SSH_FX_FILE_ALREADY_EXISTS:
+      return CURLE_REMOTE_FILE_EXISTS;
+
+    default:
+      break;
+  }
+
+  return CURLE_SSH;
+}
+
+/*
  * SSH State machine related code
  */
 /* This is the ONLY way to change SSH state! */
@@ -349,6 +420,13 @@ cleanup:
   break; \
 }
 
+#define MOVE_TO_SFTP_CLOSE_STATE() { \
+  state(conn, SSH_SFTP_CLOSE); \
+  sshc->actualcode = sftp_error_to_CURLE(sftp_get_error(sshc->sftp_session)); \
+  rc = SSH_ERROR; \
+  break; \
+}
+
 #define MOVE_TO_LAST_AUTH \
   if(sshc->auth_methods & SSH_AUTH_METHOD_PASSWORD) { \
     rc = SSH_OK; \
@@ -359,6 +437,16 @@ cleanup:
     MOVE_TO_ERROR_STATE(CURLE_LOGIN_DENIED); \
   }
 
+#define MOVE_TO_TERTIARY_AUTH \
+  if(sshc->auth_methods & SSH_AUTH_METHOD_INTERACTIVE) { \
+    rc = SSH_OK; \
+    state(conn, SSH_AUTH_KEY_INIT); \
+    break; \
+  } \
+  else { \
+    MOVE_TO_LAST_AUTH; \
+  }
+
 #define MOVE_TO_SECONDARY_AUTH \
   if(sshc->auth_methods & SSH_AUTH_METHOD_GSSAPI_MIC) { \
     rc = SSH_OK; \
@@ -366,9 +454,73 @@ cleanup:
     break; \
   } \
   else { \
-    MOVE_TO_LAST_AUTH; \
+    MOVE_TO_TERTIARY_AUTH; \
   }
 
+static
+int myssh_auth_interactive(struct connectdata *conn)
+{
+  int rc;
+  struct ssh_conn *sshc = &conn->proto.sshc;
+  int nprompts;
+
+restart:
+  switch(sshc->kbd_state) {
+    case 0:
+      rc = ssh_userauth_kbdint(sshc->ssh_session, NULL, NULL);
+      if(rc == SSH_AUTH_AGAIN)
+        return SSH_AGAIN;
+
+      if(rc != SSH_AUTH_INFO)
+        return SSH_ERROR;
+
+      nprompts = ssh_userauth_kbdint_getnprompts(sshc->ssh_session);
+      if(nprompts == SSH_ERROR || nprompts != 1)
+        return SSH_ERROR;
+
+      rc = ssh_userauth_kbdint_setanswer(sshc->ssh_session, 0, conn->passwd);
+      if(rc < 0)
+        return SSH_ERROR;
+
+    /* fallthrough */
+    case 1:
+      sshc->kbd_state = 1;
+
+      rc = ssh_userauth_kbdint(sshc->ssh_session, NULL, NULL);
+      if(rc == SSH_AUTH_AGAIN)
+        return SSH_AGAIN;
+      else if(rc == SSH_AUTH_SUCCESS)
+        rc = SSH_OK;
+      else if(rc == SSH_AUTH_INFO) {
+        nprompts = ssh_userauth_kbdint_getnprompts(sshc->ssh_session);
+        if(nprompts != 0)
+          return SSH_ERROR;
+
+        sshc->kbd_state = 2;
+        goto restart;
+      }
+      else
+        rc = SSH_ERROR;
+      break;
+    case 2:
+      sshc->kbd_state = 2;
+
+      rc = ssh_userauth_kbdint(sshc->ssh_session, NULL, NULL);
+      if(rc == SSH_AUTH_AGAIN)
+        return SSH_AGAIN;
+      else if(rc == SSH_AUTH_SUCCESS)
+        rc = SSH_OK;
+      else
+        rc = SSH_ERROR;
+
+      break;
+    default:
+      return SSH_ERROR;
+  }
+
+  sshc->kbd_state = 0;
+  return rc;
+}
 
 /*
  * ssh_statemach_act() runs the SSH state machine as far as it can without
@@ -382,7 +534,9 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
   struct Curl_easy *data = conn->data;
   struct SSHPROTO *protop = data->req.protop;
   struct ssh_conn *sshc = &conn->proto.sshc;
-  int rc = SSH_NO_ERROR;
+  int rc = SSH_NO_ERROR, err;
+  char *new_readdir_line;
+  int seekerr = CURL_SEEKFUNC_OK;
   const char *err_msg;
   *block = 0;                   /* we're not blocking by default */
 
@@ -395,7 +549,7 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
       sshc->actualcode = CURLE_OK;
 
 #if 0
-      ssh_set_log_level(SSH_LOG_PACKET);
+      ssh_set_log_level(SSH_LOG_PROTOCOL);
 #endif
 
       /* Set libssh to non-blocking, since everything internally is
@@ -453,6 +607,9 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
         else if(sshc->auth_methods & SSH_AUTH_METHOD_GSSAPI_MIC) {
           state(conn, SSH_AUTH_GSSAPI);
         }
+        else if(sshc->auth_methods & SSH_AUTH_METHOD_INTERACTIVE) {
+          state(conn, SSH_AUTH_KEY_INIT);
+        }
         else if(sshc->auth_methods & SSH_AUTH_METHOD_PASSWORD) {
           state(conn, SSH_AUTH_PASS_INIT);
         }
@@ -538,7 +695,7 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
 
     case SSH_AUTH_GSSAPI:
       if(!(data->set.ssh_auth_types & CURLSSH_AUTH_GSSAPI)) {
-        MOVE_TO_LAST_AUTH;
+        MOVE_TO_TERTIARY_AUTH;
       }
 
       rc = ssh_userauth_gssapi(sshc->ssh_session);
@@ -555,7 +712,30 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
         break;
       }
 
-      MOVE_TO_LAST_AUTH;
+      MOVE_TO_TERTIARY_AUTH;
+      break;
+
+    case SSH_AUTH_KEY_INIT:
+      if(data->set.ssh_auth_types & CURLSSH_AUTH_KEYBOARD) {
+        state(conn, SSH_AUTH_KEY);
+      }
+      else {
+        MOVE_TO_LAST_AUTH;
+      }
+      break;
+
+    case SSH_AUTH_KEY:
+
+      /* Authentication failed. Continue with keyboard-interactive now. */
+      rc = myssh_auth_interactive(conn);
+      if(rc == SSH_AGAIN) {
+        break;
+      }
+      if(rc == SSH_OK) {
+        sshc->authed = TRUE;
+        infof(data, "completed keyboard interactive authentication\n");
+      }
+      state(conn, SSH_AUTH_DONE);
       break;
 
     case SSH_AUTH_PASS_INIT:
@@ -600,10 +780,887 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
       conn->sockfd = ssh_get_fd(sshc->ssh_session);
       conn->writesockfd = CURL_SOCKET_BAD;
 
+      if(conn->handler->protocol == CURLPROTO_SFTP) {
+        state(conn, SSH_SFTP_INIT);
+        break;
+      }
       infof(data, "SSH CONNECT phase done\n");
       state(conn, SSH_STOP);
       break;
 
+    case SSH_SFTP_INIT:
+      ssh_set_blocking(sshc->ssh_session, 1);
+
+      sshc->sftp_session = sftp_new(sshc->ssh_session);
+      if(!sshc->sftp_session) {
+        failf(data, "Failure initializing sftp session: %s",
+              ssh_get_error(sshc->ssh_session));
+        MOVE_TO_ERROR_STATE(CURLE_COULDNT_CONNECT);
+        break;
+      }
+
+      rc = sftp_init(sshc->sftp_session);
+      if(rc != SSH_OK) {
+        rc = sftp_get_error(sshc->sftp_session);
+        failf(data, "Failure initializing sftp session: %s",
+              ssh_get_error(sshc->ssh_session));
+        MOVE_TO_ERROR_STATE(sftp_error_to_CURLE(rc));
+        break;
+      }
+      state(conn, SSH_SFTP_REALPATH);
+      /* fall through */
+    case SSH_SFTP_REALPATH:
+      /*
+       * Get the "home" directory
+       */
+      sshc->homedir = sftp_canonicalize_path(sshc->sftp_session, ".");
+      if(sshc->homedir == NULL) {
+        MOVE_TO_ERROR_STATE(CURLE_COULDNT_CONNECT);
+      }
+      conn->data->state.most_recent_ftp_entrypath = sshc->homedir;
+
+      /* This is the last step in the SFTP connect phase. Do note that while
+         we get the homedir here, we get the "workingpath" in the DO action
+         since the homedir will remain the same between request but the
+         working path will not. */
+      DEBUGF(infof(data, "SSH CONNECT phase done\n"));
+      state(conn, SSH_STOP);
+      break;
+
+    case SSH_SFTP_QUOTE_INIT:
+
+      result = Curl_getworkingpath(conn, sshc->homedir, &protop->path);
+      if(result) {
+        sshc->actualcode = result;
+        state(conn, SSH_STOP);
+        break;
+      }
+
+      if(data->set.quote) {
+        infof(data, "Sending quote commands\n");
+        sshc->quote_item = data->set.quote;
+        state(conn, SSH_SFTP_QUOTE);
+      }
+      else {
+        state(conn, SSH_SFTP_GETINFO);
+      }
+      break;
+
+    case SSH_SFTP_POSTQUOTE_INIT:
+      if(data->set.postquote) {
+        infof(data, "Sending quote commands\n");
+        sshc->quote_item = data->set.postquote;
+        state(conn, SSH_SFTP_QUOTE);
+      }
+      else {
+        state(conn, SSH_STOP);
+      }
+      break;
+
+    case SSH_SFTP_QUOTE:
+      /* Send any quote commands */
+      sftp_quote(conn);
+      break;
+
+    case SSH_SFTP_NEXT_QUOTE:
+      Curl_safefree(sshc->quote_path1);
+      Curl_safefree(sshc->quote_path2);
+
+      sshc->quote_item = sshc->quote_item->next;
+
+      if(sshc->quote_item) {
+        state(conn, SSH_SFTP_QUOTE);
+      }
+      else {
+        if(sshc->nextstate != SSH_NO_STATE) {
+          state(conn, sshc->nextstate);
+          sshc->nextstate = SSH_NO_STATE;
+        }
+        else {
+          state(conn, SSH_SFTP_GETINFO);
+        }
+      }
+      break;
+
+    case SSH_SFTP_QUOTE_STAT:
+      sftp_quote_stat(conn);
+      break;
+
+    case SSH_SFTP_QUOTE_SETSTAT:
+      rc = sftp_setstat(sshc->sftp_session, sshc->quote_path2,
+                        sshc->quote_attrs);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        Curl_safefree(sshc->quote_path2);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "Attempt to set SFTP stats failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        /* sshc->actualcode = sftp_error_to_CURLE(err);
+         * we do not send the actual error; we return
+         * the error the libssh2 backend is returning */
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_SYMLINK:
+      rc = sftp_symlink(sshc->sftp_session, sshc->quote_path2,
+                        sshc->quote_path1);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        Curl_safefree(sshc->quote_path2);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "symlink command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_MKDIR:
+      rc = sftp_mkdir(sshc->sftp_session, sshc->quote_path1,
+                      (mode_t)data->set.new_directory_perms);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "mkdir command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_RENAME:
+      rc = sftp_rename(sshc->sftp_session, sshc->quote_path1,
+                       sshc->quote_path2);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        Curl_safefree(sshc->quote_path2);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "rename command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_RMDIR:
+      rc = sftp_rmdir(sshc->sftp_session, sshc->quote_path1);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "rmdir command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_UNLINK:
+      rc = sftp_unlink(sshc->sftp_session, sshc->quote_path1);
+      if(rc != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "rm command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        break;
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+
+    case SSH_SFTP_QUOTE_STATVFS:
+    {
+      sftp_statvfs_t statvfs;
+
+      statvfs = sftp_statvfs(sshc->sftp_session, sshc->quote_path1);
+      if(statvfs != 0 && !sshc->acceptfail) {
+        Curl_safefree(sshc->quote_path1);
+        err = sftp_get_error(sshc->sftp_session);
+        failf(data, "statvfs command failed: %s",
+              ssh_get_error(sshc->ssh_session));
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = CURLE_QUOTE_ERROR;
+        if(statvfs)
+          sftp_statvfs_free(statvfs);
+        break;
+      }
+      else {
+        char *tmp = aprintf("statvfs:\n"
+                            "f_bsize: %llu\n" "f_frsize: %llu\n"
+                            "f_blocks: %llu\n" "f_bfree: %llu\n"
+                            "f_bavail: %llu\n" "f_files: %llu\n"
+                            "f_ffree: %llu\n" "f_favail: %llu\n"
+                            "f_fsid: %llu\n" "f_flag: %llu\n"
+                            "f_namemax: %llu\n",
+                            statvfs->f_bsize, statvfs->f_frsize,
+                            statvfs->f_blocks, statvfs->f_bfree,
+                            statvfs->f_bavail, statvfs->f_files,
+                            statvfs->f_ffree, statvfs->f_favail,
+                            statvfs->f_fsid, statvfs->f_flag,
+                            statvfs->f_namemax);
+        sftp_statvfs_free(statvfs);
+
+        if(!tmp) {
+          result = CURLE_OUT_OF_MEMORY;
+          state(conn, SSH_SFTP_CLOSE);
+          sshc->nextstate = SSH_NO_STATE;
+          break;
+        }
+
+        result = Curl_client_write(conn, CLIENTWRITE_HEADER, tmp, strlen(tmp));
+        free(tmp);
+        if(result) {
+          state(conn, SSH_SFTP_CLOSE);
+          sshc->nextstate = SSH_NO_STATE;
+          sshc->actualcode = result;
+        }
+      }
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+      break;
+    }
+
+    case SSH_SFTP_GETINFO:
+      if(data->set.get_filetime) {
+        state(conn, SSH_SFTP_FILETIME);
+      }
+      else {
+        state(conn, SSH_SFTP_TRANS_INIT);
+      }
+      break;
+
+    case SSH_SFTP_FILETIME:
+    {
+      sftp_attributes attrs;
+
+      attrs = sftp_stat(sshc->sftp_session, protop->path);
+      if(attrs != 0) {
+        data->info.filetime = (long)attrs->mtime;
+        sftp_attributes_free(attrs);
+      }
+
+      state(conn, SSH_SFTP_TRANS_INIT);
+      break;
+    }
+
+    case SSH_SFTP_TRANS_INIT:
+      if(data->set.upload)
+        state(conn, SSH_SFTP_UPLOAD_INIT);
+      else {
+        if(protop->path[strlen(protop->path)-1] == '/')
+          state(conn, SSH_SFTP_READDIR_INIT);
+        else
+          state(conn, SSH_SFTP_DOWNLOAD_INIT);
+      }
+      break;
+
+    case SSH_SFTP_UPLOAD_INIT:
+    {
+      int flags;
+
+      if(data->state.resume_from != 0) {
+        sftp_attributes attrs;
+
+        if(data->state.resume_from < 0) {
+          attrs = sftp_stat(sshc->sftp_session, protop->path);
+          if(attrs != 0) {
+            curl_off_t size = attrs->size;
+            if(size < 0) {
+              failf(data, "Bad file size (%" CURL_FORMAT_CURL_OFF_T ")", size);
+              MOVE_TO_ERROR_STATE(CURLE_BAD_DOWNLOAD_RESUME);
+            }
+            data->state.resume_from = attrs->size;
+
+            sftp_attributes_free(attrs);
+          }
+          else {
+            data->state.resume_from = 0;
+          }
+        }
+      }
+
+      if(data->set.ftp_append)
+        /* Try to open for append, but create if nonexisting */
+        flags = O_WRONLY|O_CREAT|O_APPEND;
+      else if(data->state.resume_from > 0)
+        /* If we have restart position then open for append */
+        flags = O_WRONLY|O_APPEND;
+      else
+        /* Clear file before writing (normal behaviour) */
+        flags = O_WRONLY|O_APPEND|O_CREAT|O_TRUNC;
+
+      if(sshc->sftp_file)
+        sftp_close(sshc->sftp_file);
+      sshc->sftp_file =
+        sftp_open(sshc->sftp_session, protop->path,
+                  flags, (mode_t)data->set.new_file_perms);
+      if(!sshc->sftp_file) {
+        err = sftp_get_error(sshc->sftp_session);
+
+        if(((err == SSH_FX_NO_SUCH_FILE || err == SSH_FX_FAILURE ||
+             err == SSH_FX_NO_SUCH_PATH)) &&
+             (data->set.ftp_create_missing_dirs &&
+             (strlen(protop->path) > 1))) {
+               /* try to create the path remotely */
+               rc = 0;
+               sshc->secondCreateDirs = 1;
+               state(conn, SSH_SFTP_CREATE_DIRS_INIT);
+               break;
+        }
+        else {
+          MOVE_TO_SFTP_CLOSE_STATE();
+        }
+      }
+
+      /* If we have a restart point then we need to seek to the correct
+         position. */
+      if(data->state.resume_from > 0) {
+        /* Let's read off the proper amount of bytes from the input. */
+        if(conn->seek_func) {
+          seekerr = conn->seek_func(conn->seek_client, data->state.resume_from,
+                                    SEEK_SET);
+        }
+
+        if(seekerr != CURL_SEEKFUNC_OK) {
+          curl_off_t passed = 0;
+
+          if(seekerr != CURL_SEEKFUNC_CANTSEEK) {
+            failf(data, "Could not seek stream");
+            return CURLE_FTP_COULDNT_USE_REST;
+          }
+          /* seekerr == CURL_SEEKFUNC_CANTSEEK (can't seek to offset) */
+          do {
+            size_t readthisamountnow =
+              (data->state.resume_from - passed > data->set.buffer_size) ?
+              (size_t)data->set.buffer_size :
+              curlx_sotouz(data->state.resume_from - passed);
+
+            size_t actuallyread =
+              data->state.fread_func(data->state.buffer, 1,
+                                     readthisamountnow, data->state.in);
+
+            passed += actuallyread;
+            if((actuallyread == 0) || (actuallyread > readthisamountnow)) {
+              /* this checks for greater-than only to make sure that the
+                 CURL_READFUNC_ABORT return code still aborts */
+              failf(data, "Failed to read data");
+              MOVE_TO_ERROR_STATE(CURLE_FTP_COULDNT_USE_REST);
+            }
+          } while(passed < data->state.resume_from);
+        }
+
+        /* now, decrease the size of the read */
+        if(data->state.infilesize > 0) {
+          data->state.infilesize -= data->state.resume_from;
+          data->req.size = data->state.infilesize;
+          Curl_pgrsSetUploadSize(data, data->state.infilesize);
+        }
+
+        rc = sftp_seek64(sshc->sftp_file, data->state.resume_from);
+        if(rc != 0) {
+          MOVE_TO_SFTP_CLOSE_STATE();
+        }
+      }
+      if(data->state.infilesize > 0) {
+        data->req.size = data->state.infilesize;
+        Curl_pgrsSetUploadSize(data, data->state.infilesize);
+      }
+      /* upload data */
+      Curl_setup_transfer(conn, -1, -1, FALSE, NULL, FIRSTSOCKET, NULL);
+
+      /* not set by Curl_setup_transfer to preserve keepon bits */
+      conn->sockfd = conn->writesockfd;
+
+      /* store this original bitmask setup to use later on if we can't
+         figure out a "real" bitmask */
+      sshc->orig_waitfor = data->req.keepon;
+
+      /* we want to use the _sending_ function even when the socket turns
+         out readable as the underlying libssh sftp send function will deal
+         with both accordingly */
+      conn->cselect_bits = CURL_CSELECT_OUT;
+
+      /* since we don't really wait for anything at this point, we want the
+         state machine to move on as soon as possible so we set a very short
+         timeout here */
+      Curl_expire(data, 0, EXPIRE_RUN_NOW);
+
+      state(conn, SSH_STOP);
+      break;
+    }
+
+    case SSH_SFTP_CREATE_DIRS_INIT:
+      if(strlen(protop->path) > 1) {
+        sshc->slash_pos = protop->path + 1; /* ignore the leading '/' */
+        state(conn, SSH_SFTP_CREATE_DIRS);
+      }
+      else {
+        state(conn, SSH_SFTP_UPLOAD_INIT);
+      }
+      break;
+
+    case SSH_SFTP_CREATE_DIRS:
+      sshc->slash_pos = strchr(sshc->slash_pos, '/');
+      if(sshc->slash_pos) {
+        *sshc->slash_pos = 0;
+
+        infof(data, "Creating directory '%s'\n", protop->path);
+        state(conn, SSH_SFTP_CREATE_DIRS_MKDIR);
+        break;
+      }
+      state(conn, SSH_SFTP_UPLOAD_INIT);
+      break;
+
+    case SSH_SFTP_CREATE_DIRS_MKDIR:
+      /* 'mode' - parameter is preliminary - default to 0644 */
+      rc = sftp_mkdir(sshc->sftp_session, protop->path,
+                      (mode_t)data->set.new_directory_perms);
+      *sshc->slash_pos = '/';
+      ++sshc->slash_pos;
+      if(rc < 0) {
+        /*
+         * Abort if failure wasn't that the dir already exists or the
+         * permission was denied (creation might succeed further down the
+         * path) - retry on unspecific FAILURE also
+         */
+        err = sftp_get_error(sshc->sftp_session);
+        if((err != SSH_FX_FILE_ALREADY_EXISTS) &&
+           (err != SSH_FX_FAILURE) &&
+           (err != SSH_FX_PERMISSION_DENIED)) {
+          MOVE_TO_SFTP_CLOSE_STATE();
+        }
+        rc = 0; /* clear rc and continue */
+      }
+      state(conn, SSH_SFTP_CREATE_DIRS);
+      break;
+
+    case SSH_SFTP_READDIR_INIT:
+      Curl_pgrsSetDownloadSize(data, -1);
+      if(data->set.opt_no_body) {
+        state(conn, SSH_STOP);
+        break;
+      }
+
+      /*
+       * This is a directory that we are trying to get, so produce a directory
+       * listing
+       */
+      sshc->sftp_dir = sftp_opendir(sshc->sftp_session,
+                                    protop->path);
+      if(!sshc->sftp_dir) {
+        failf(data, "Could not open directory for reading: %s",
+              ssh_get_error(sshc->ssh_session));
+        MOVE_TO_SFTP_CLOSE_STATE();
+      }
+      state(conn, SSH_SFTP_READDIR);
+      break;
+
+    case SSH_SFTP_READDIR:
+
+      if(sshc->readdir_attrs)
+        sftp_attributes_free(sshc->readdir_attrs);
+
+      sshc->readdir_attrs = sftp_readdir(sshc->sftp_session, sshc->sftp_dir);
+      if(sshc->readdir_attrs) {
+        sshc->readdir_filename = sshc->readdir_attrs->name;
+        sshc->readdir_longentry = sshc->readdir_attrs->longname;
+        sshc->readdir_len = (int)strlen(sshc->readdir_filename);
+
+        if(data->set.ftp_list_only) {
+          char *tmpLine;
+
+          tmpLine = aprintf("%s\n", sshc->readdir_filename);
+          if(tmpLine == NULL) {
+            state(conn, SSH_SFTP_CLOSE);
+            sshc->actualcode = CURLE_OUT_OF_MEMORY;
+            break;
+          }
+          result = Curl_client_write(conn, CLIENTWRITE_BODY,
+                                     tmpLine, sshc->readdir_len + 1);
+          free(tmpLine);
+
+          if(result) {
+            state(conn, SSH_STOP);
+            break;
+          }
+          /* since this counts what we send to the client, we include the
+             newline in this counter */
+          data->req.bytecount += sshc->readdir_len + 1;
+
+          /* output debug output if that is requested */
+          if(data->set.verbose) {
+            Curl_debug(data, CURLINFO_DATA_OUT,
+                       (char *)sshc->readdir_filename,
+                       sshc->readdir_len, conn);
+          }
+        }
+        else {
+          sshc->readdir_currLen = (int)strlen(sshc->readdir_longentry);
+          sshc->readdir_totalLen = 80 + sshc->readdir_currLen;
+          sshc->readdir_line = calloc(sshc->readdir_totalLen, 1);
+          if(!sshc->readdir_line) {
+            state(conn, SSH_SFTP_CLOSE);
+            sshc->actualcode = CURLE_OUT_OF_MEMORY;
+            break;
+          }
+
+          memcpy(sshc->readdir_line, sshc->readdir_longentry,
+                 sshc->readdir_currLen);
+          if((sshc->readdir_attrs->flags & SSH_FILEXFER_ATTR_PERMISSIONS) &&
+             ((sshc->readdir_attrs->permissions & S_IFMT) ==
+              S_IFLNK)) {
+            sshc->readdir_linkPath = malloc(PATH_MAX + 1);
+            if(sshc->readdir_linkPath == NULL) {
+              state(conn, SSH_SFTP_CLOSE);
+              sshc->actualcode = CURLE_OUT_OF_MEMORY;
+              break;
+            }
+
+            snprintf(sshc->readdir_linkPath, PATH_MAX, "%s%s", protop->path,
+                     sshc->readdir_filename);
+
+            state(conn, SSH_SFTP_READDIR_LINK);
+            break;
+          }
+          state(conn, SSH_SFTP_READDIR_BOTTOM);
+          break;
+        }
+      }
+      else if(sshc->readdir_attrs == NULL && sftp_dir_eof(sshc->sftp_dir)) {
+        state(conn, SSH_SFTP_READDIR_DONE);
+        break;
+      }
+      else {
+        failf(data, "Could not open remote file for reading: %s",
+              ssh_get_error(sshc->ssh_session));
+        MOVE_TO_SFTP_CLOSE_STATE();
+        break;
+      }
+      break;
+
+    case SSH_SFTP_READDIR_LINK:
+      if(sshc->readdir_link_attrs)
+        sftp_attributes_free(sshc->readdir_link_attrs);
+
+      sshc->readdir_link_attrs = sftp_lstat(sshc->sftp_session,
+                                            sshc->readdir_linkPath);
+      if(sshc->readdir_link_attrs == 0) {
+        failf(data, "Could not read symlink for reading: %s",
+              ssh_get_error(sshc->ssh_session));
+        MOVE_TO_SFTP_CLOSE_STATE();
+      }
+
+      if(sshc->readdir_link_attrs->name == NULL) {
+        sshc->readdir_tmp = sftp_readlink(sshc->sftp_session,
+                                          sshc->readdir_linkPath);
+        if(sshc->readdir_filename == NULL)
+          sshc->readdir_len = 0;
+        else
+          sshc->readdir_len = (int)strlen(sshc->readdir_tmp);
+        sshc->readdir_longentry = NULL;
+        sshc->readdir_filename = sshc->readdir_tmp;
+      }
+      else {
+        sshc->readdir_len = (int)strlen(sshc->readdir_link_attrs->name);
+        sshc->readdir_filename = sshc->readdir_link_attrs->name;
+        sshc->readdir_longentry = sshc->readdir_link_attrs->longname;
+      }
+
+      Curl_safefree(sshc->readdir_linkPath);
+
+      /* get room for the filename and extra output */
+      sshc->readdir_totalLen += 4 + sshc->readdir_len;
+      new_readdir_line = Curl_saferealloc(sshc->readdir_line,
+                                          sshc->readdir_totalLen);
+      if(!new_readdir_line) {
+        sshc->readdir_line = NULL;
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->actualcode = CURLE_OUT_OF_MEMORY;
+        break;
+      }
+      sshc->readdir_line = new_readdir_line;
+
+      sshc->readdir_currLen += snprintf(sshc->readdir_line +
+                                        sshc->readdir_currLen,
+                                        sshc->readdir_totalLen -
+                                        sshc->readdir_currLen,
+                                        " -> %s",
+                                        sshc->readdir_filename);
+
+      sftp_attributes_free(sshc->readdir_link_attrs);
+      sshc->readdir_link_attrs = NULL;
+      sshc->readdir_filename = NULL;
+      sshc->readdir_longentry = NULL;
+
+      state(conn, SSH_SFTP_READDIR_BOTTOM);
+      /* fall through */
+    case SSH_SFTP_READDIR_BOTTOM:
+      sshc->readdir_currLen += snprintf(sshc->readdir_line +
+                                        sshc->readdir_currLen,
+                                        sshc->readdir_totalLen -
+                                        sshc->readdir_currLen, "\n");
+      result = Curl_client_write(conn, CLIENTWRITE_BODY,
+                                 sshc->readdir_line,
+                                 sshc->readdir_currLen);
+
+      if(!result) {
+
+        /* output debug output if that is requested */
+        if(data->set.verbose) {
+          Curl_debug(data, CURLINFO_DATA_OUT, sshc->readdir_line,
+                     sshc->readdir_currLen, conn);
+        }
+        data->req.bytecount += sshc->readdir_currLen;
+      }
+      Curl_safefree(sshc->readdir_line);
+      ssh_string_free_char(sshc->readdir_tmp);
+      sshc->readdir_tmp = NULL;
+
+      if(result) {
+        state(conn, SSH_STOP);
+      }
+      else
+        state(conn, SSH_SFTP_READDIR);
+      break;
+
+    case SSH_SFTP_READDIR_DONE:
+      sftp_closedir(sshc->sftp_dir);
+      sshc->sftp_dir = NULL;
+
+      /* no data to transfer */
+      Curl_setup_transfer(conn, -1, -1, FALSE, NULL, -1, NULL);
+      state(conn, SSH_STOP);
+      break;
+
+    case SSH_SFTP_DOWNLOAD_INIT:
+      /*
+       * Work on getting the specified file
+       */
+      if(sshc->sftp_file)
+        sftp_close(sshc->sftp_file);
+
+      sshc->sftp_file = sftp_open(sshc->sftp_session, protop->path,
+                                  O_RDONLY, (mode_t)data->set.new_file_perms);
+      if(!sshc->sftp_file) {
+        failf(data, "Could not open remote file for reading: %s",
+              ssh_get_error(sshc->ssh_session));
+
+        MOVE_TO_SFTP_CLOSE_STATE();
+      }
+
+      state(conn, SSH_SFTP_DOWNLOAD_STAT);
+      break;
+
+    case SSH_SFTP_DOWNLOAD_STAT:
+    {
+      sftp_attributes attrs;
+      curl_off_t size;
+
+      attrs = sftp_fstat(sshc->sftp_file);
+      if(!attrs ||
+              !(attrs->flags & SSH_FILEXFER_ATTR_SIZE) ||
+              (attrs->size == 0)) {
+        /*
+         * sftp_fstat didn't return an error, so maybe the server
+         * just doesn't support stat()
+         * OR the server doesn't return a file size with a stat()
+         * OR file size is 0
+         */
+        data->req.size = -1;
+        data->req.maxdownload = -1;
+        Curl_pgrsSetDownloadSize(data, -1);
+        size = 0;
+      }
+      else {
+        size = attrs->size;
+
+        sftp_attributes_free(attrs);
+
+        if(size < 0) {
+          failf(data, "Bad file size (%" CURL_FORMAT_CURL_OFF_T ")", size);
+          return CURLE_BAD_DOWNLOAD_RESUME;
+        }
+        if(conn->data->state.use_range) {
+          curl_off_t from, to;
+          char *ptr;
+          char *ptr2;
+          CURLofft to_t;
+          CURLofft from_t;
+
+          from_t = curlx_strtoofft(conn->data->state.range, &ptr, 0, &from);
+          if(from_t == CURL_OFFT_FLOW) {
+            return CURLE_RANGE_ERROR;
+          }
+          while(*ptr && (ISSPACE(*ptr) || (*ptr == '-')))
+            ptr++;
+          to_t = curlx_strtoofft(ptr, &ptr2, 0, &to);
+          if(to_t == CURL_OFFT_FLOW) {
+            return CURLE_RANGE_ERROR;
+          }
+          if((to_t == CURL_OFFT_INVAL) /* no "to" value given */
+             || (to >= size)) {
+            to = size - 1;
+          }
+          if(from_t) {
+            /* from is relative to end of file */
+            from = size - to;
+            to = size - 1;
+          }
+          if(from > size) {
+            failf(data, "Offset (%"
+                  CURL_FORMAT_CURL_OFF_T ") was beyond file size (%"
+                  CURL_FORMAT_CURL_OFF_T ")", from, size);
+            return CURLE_BAD_DOWNLOAD_RESUME;
+          }
+          if(from > to) {
+            from = to;
+            size = 0;
+          }
+          else {
+            size = to - from + 1;
+          }
+
+          rc = sftp_seek64(sshc->sftp_file, from);
+          if(rc != 0) {
+            MOVE_TO_SFTP_CLOSE_STATE();
+          }
+        }
+        data->req.size = size;
+        data->req.maxdownload = size;
+        Curl_pgrsSetDownloadSize(data, size);
+      }
+
+      /* We can resume if we can seek to the resume position */
+      if(data->state.resume_from) {
+        if(data->state.resume_from < 0) {
+          /* We're supposed to download the last abs(from) bytes */
+          if((curl_off_t)size < -data->state.resume_from) {
+            failf(data, "Offset (%"
+                  CURL_FORMAT_CURL_OFF_T ") was beyond file size (%"
+                  CURL_FORMAT_CURL_OFF_T ")",
+                  data->state.resume_from, size);
+            return CURLE_BAD_DOWNLOAD_RESUME;
+          }
+          /* download from where? */
+          data->state.resume_from += size;
+        }
+        else {
+          if((curl_off_t)size < data->state.resume_from) {
+            failf(data, "Offset (%" CURL_FORMAT_CURL_OFF_T
+                  ") was beyond file size (%" CURL_FORMAT_CURL_OFF_T ")",
+                  data->state.resume_from, size);
+            return CURLE_BAD_DOWNLOAD_RESUME;
+          }
+        }
+        /* Does a completed file need to be seeked and started or closed ? */
+        /* Now store the number of bytes we are expected to download */
+        data->req.size = size - data->state.resume_from;
+        data->req.maxdownload = size - data->state.resume_from;
+        Curl_pgrsSetDownloadSize(data,
+                                 size - data->state.resume_from);
+
+        rc = sftp_seek64(sshc->sftp_file, data->state.resume_from);
+        if(rc != 0) {
+          MOVE_TO_SFTP_CLOSE_STATE();
+        }
+      }
+    }
+
+    /* Setup the actual download */
+    if(data->req.size == 0) {
+      /* no data to transfer */
+      Curl_setup_transfer(conn, -1, -1, FALSE, NULL, -1, NULL);
+      infof(data, "File already completely downloaded\n");
+      state(conn, SSH_STOP);
+      break;
+    }
+    Curl_setup_transfer(conn, FIRSTSOCKET, data->req.size,
+                        FALSE, NULL, -1, NULL);
+
+    /* not set by Curl_setup_transfer to preserve keepon bits */
+    conn->writesockfd = conn->sockfd;
+
+    /* we want to use the _receiving_ function even when the socket turns
+       out writableable as the underlying libssh recv function will deal
+       with both accordingly */
+    conn->cselect_bits = CURL_CSELECT_IN;
+
+    if(result) {
+      /* this should never occur; the close state should be entered
+         at the time the error occurs */
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->actualcode = result;
+    }
+    else {
+      sshc->sftp_recv_state = 0;
+      state(conn, SSH_STOP);
+    }
+    break;
+
+    case SSH_SFTP_CLOSE:
+      if(sshc->sftp_file) {
+        sftp_close(sshc->sftp_file);
+        sshc->sftp_file = NULL;
+      }
+      if(protop)
+        Curl_safefree(protop->path);
+
+      DEBUGF(infof(data, "SFTP DONE done\n"));
+
+      /* Check if nextstate is set and move .nextstate could be POSTQUOTE_INIT
+         After nextstate is executed, the control should come back to
+         SSH_SFTP_CLOSE to pass the correct result back  */
+      if(sshc->nextstate != SSH_NO_STATE &&
+         sshc->nextstate != SSH_SFTP_CLOSE) {
+        state(conn, sshc->nextstate);
+        sshc->nextstate = SSH_SFTP_CLOSE;
+      }
+      else {
+        state(conn, SSH_STOP);
+        result = sshc->actualcode;
+      }
+      break;
+
+    case SSH_SFTP_SHUTDOWN:
+      /* during times we get here due to a broken transfer and then the
+         sftp_handle might not have been taken down so make sure that is done
+         before we proceed */
+
+      if(sshc->sftp_file) {
+        sftp_close(sshc->sftp_file);
+        sshc->sftp_file = NULL;
+      }
+
+      if(sshc->sftp_session) {
+        sftp_free(sshc->sftp_session);
+        sshc->sftp_session = NULL;
+      }
+
+      Curl_safefree(sshc->homedir);
+      conn->data->state.most_recent_ftp_entrypath = NULL;
+
+      state(conn, SSH_SESSION_DISCONNECT);
+      break;
+
+
     case SSH_SCP_TRANS_INIT:
       result = Curl_getworkingpath(conn, sshc->homedir, &protop->path);
       if(result) {
@@ -781,6 +1838,20 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
       DEBUGASSERT(sshc->ssh_session == NULL);
       DEBUGASSERT(sshc->scp_session == NULL);
 
+      if(sshc->readdir_tmp) {
+        ssh_string_free_char(sshc->readdir_tmp);
+        sshc->readdir_tmp = NULL;
+      }
+
+      if(sshc->quote_attrs)
+        sftp_attributes_free(sshc->quote_attrs);
+
+      if(sshc->readdir_attrs)
+        sftp_attributes_free(sshc->readdir_attrs);
+
+      if(sshc->readdir_link_attrs)
+        sftp_attributes_free(sshc->readdir_link_attrs);
+
       if(sshc->privkey)
         ssh_key_free(sshc->privkey);
       if(sshc->pubkey)
@@ -794,8 +1865,6 @@ static CURLcode myssh_statemach_act(struct connectdata *conn, bool *block)
 
       Curl_safefree(sshc->homedir);
 
-      Curl_safefree(sshc->readdir_filename);
-      Curl_safefree(sshc->readdir_longentry);
       Curl_safefree(sshc->readdir_line);
       Curl_safefree(sshc->readdir_linkPath);
 
@@ -877,7 +1946,7 @@ static void myssh_block2waitfor(struct connectdata *conn, bool block)
   if(block) {
     dir = ssh_get_poll_flags(sshc->ssh_session);
     if(dir & SSH_READ_PENDING) {
-      /* translate the libssh2 define bits into our own bit defines */
+      /* translate the libssh define bits into our own bit defines */
       conn->waitfor = KEEP_RECV;
     }
     else if(dir & SSH_WRITE_PENDING) {
@@ -961,8 +2030,8 @@ static CURLcode myssh_setup_connection(struct connectdata *conn)
   return CURLE_OK;
 }
 
-static Curl_recv scp_recv;
-static Curl_send scp_send;
+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
@@ -987,8 +2056,10 @@ static CURLcode myssh_connect(struct connectdata *conn, bool *done)
     conn->recv[FIRSTSOCKET] = scp_recv;
     conn->send[FIRSTSOCKET] = scp_send;
   }
-  else
-    return CURLE_SSH;
+  else {
+    conn->recv[FIRSTSOCKET] = sftp_recv;
+    conn->send[FIRSTSOCKET] = sftp_send;
+  }
 
   ssh = &conn->proto.sshc;
 
@@ -1110,7 +2181,7 @@ static CURLcode myssh_do_it(struct connectdata *conn, bool *done)
   if(conn->handler->protocol & CURLPROTO_SCP)
     result = scp_perform(conn, &connected, done);
   else
-    result = CURLE_SSH;
+    result = sftp_perform(conn, &connected, done);
 
   return result;
 }
@@ -1231,4 +2302,446 @@ static ssize_t scp_recv(struct connectdata *conn, int sockindex,
   return nread;
 }
 
+/*
+ * =============== SFTP ===============
+ */
+
+/*
+ ***********************************************************************
+ *
+ * sftp_perform()
+ *
+ * This is the actual DO function for SFTP. Get a file/directory according to
+ * the options previously setup.
+ */
+
+static
+CURLcode sftp_perform(struct connectdata *conn,
+                      bool *connected,
+                      bool *dophase_done)
+{
+  CURLcode result = CURLE_OK;
+
+  DEBUGF(infof(conn->data, "DO phase starts\n"));
+
+  *dophase_done = FALSE; /* not done yet */
+
+  /* start the first command in the DO phase */
+  state(conn, SSH_SFTP_QUOTE_INIT);
+
+  /* run the state-machine */
+  result = myssh_multi_statemach(conn, dophase_done);
+
+  *connected = conn->bits.tcpconnect[FIRSTSOCKET];
+
+  if(*dophase_done) {
+    DEBUGF(infof(conn->data, "DO phase is complete\n"));
+  }
+
+  return result;
+}
+
+/* called from multi.c while DOing */
+static CURLcode sftp_doing(struct connectdata *conn,
+                           bool *dophase_done)
+{
+  CURLcode result = myssh_multi_statemach(conn, dophase_done);
+  if(*dophase_done) {
+    DEBUGF(infof(conn->data, "DO phase is complete\n"));
+  }
+  return result;
+}
+
+/* BLOCKING, but the function is using the state machine so the only reason
+   this is still blocking is that the multi interface code has no support for
+   disconnecting operations that takes a while */
+static CURLcode sftp_disconnect(struct connectdata *conn, bool dead_connection)
+{
+  CURLcode result = CURLE_OK;
+  (void) dead_connection;
+
+  DEBUGF(infof(conn->data, "SSH DISCONNECT starts now\n"));
+
+  if(conn->proto.sshc.ssh_session) {
+    /* only if there's a session still around to use! */
+    state(conn, SSH_SFTP_SHUTDOWN);
+    result = myssh_block_statemach(conn, TRUE);
+  }
+
+  DEBUGF(infof(conn->data, "SSH DISCONNECT is done\n"));
+
+  return result;
+
+}
+
+static CURLcode sftp_done(struct connectdata *conn, CURLcode status,
+                               bool premature)
+{
+  struct ssh_conn *sshc = &conn->proto.sshc;
+
+  if(!status) {
+    /* Post quote commands are executed after the SFTP_CLOSE state to avoid
+       errors that could happen due to open file handles during POSTQUOTE
+       operation */
+    if(!status && !premature && conn->data->set.postquote) {
+      sshc->nextstate = SSH_SFTP_POSTQUOTE_INIT;
+      state(conn, SSH_SFTP_CLOSE);
+    }
+    else
+      state(conn, SSH_SFTP_CLOSE);
+  }
+  return myssh_done(conn, status);
+}
+
+/* return number of sent bytes */
+static ssize_t sftp_send(struct connectdata *conn, int sockindex,
+                         const void *mem, size_t len, CURLcode *err)
+{
+  ssize_t nwrite;
+  (void)sockindex;
+
+  nwrite = sftp_write(conn->proto.sshc.sftp_file, mem, len);
+
+  myssh_block2waitfor(conn, FALSE);
+
+#if 0 /* not returned by libssh on write */
+  if(nwrite == SSH_AGAIN) {
+    *err = CURLE_AGAIN;
+    nwrite = 0;
+  }
+  else
+#endif
+  if(nwrite < 0) {
+    *err = CURLE_SSH;
+    nwrite = -1;
+  }
+
+  return nwrite;
+}
+
+/*
+ * Return number of received (decrypted) bytes
+ * or <0 on error
+ */
+static ssize_t sftp_recv(struct connectdata *conn, int sockindex,
+                         char *mem, size_t len, CURLcode *err)
+{
+  ssize_t nread;
+  (void)sockindex;
+
+  if(len >= (size_t)1<<32)
+    len = (size_t)(1<<31)-1;
+
+  switch(conn->proto.sshc.sftp_recv_state) {
+    case 0:
+      conn->proto.sshc.sftp_file_index =
+            sftp_async_read_begin(conn->proto.sshc.sftp_file,
+                                  (uint32_t)len);
+      if(conn->proto.sshc.sftp_file_index < 0) {
+        *err = CURLE_RECV_ERROR;
+        return -1;
+      }
+
+      /* fall-through */
+    case 1:
+      conn->proto.sshc.sftp_recv_state = 1;
+
+      nread = sftp_async_read(conn->proto.sshc.sftp_file,
+                              mem, (uint32_t)len,
+                              conn->proto.sshc.sftp_file_index);
+
+      myssh_block2waitfor(conn, (nread == SSH_AGAIN)?TRUE:FALSE);
+
+      if(nread == SSH_AGAIN) {
+        *err = CURLE_AGAIN;
+        return -1;
+      }
+      else if(nread < 0) {
+        *err = CURLE_RECV_ERROR;
+        return -1;
+      }
+
+      conn->proto.sshc.sftp_recv_state = 0;
+      return nread;
+
+    default:
+      /* we never reach here */
+      return -1;
+  }
+}
+
+static void sftp_quote(struct connectdata *conn)
+{
+  const char *cp;
+  struct Curl_easy *data = conn->data;
+  struct SSHPROTO *protop = data->req.protop;
+  struct ssh_conn *sshc = &conn->proto.sshc;
+  CURLcode result;
+
+  /*
+   * Support some of the "FTP" commands
+   */
+  char *cmd = sshc->quote_item->data;
+  sshc->acceptfail = FALSE;
+
+  /* if a command starts with an asterisk, which a legal SFTP command never
+     can, the command will be allowed to fail without it causing any
+     aborts or cancels etc. It will cause libcurl to act as if the command
+     is successful, whatever the server reponds. */
+
+  if(cmd[0] == '*') {
+    cmd++;
+    sshc->acceptfail = TRUE;
+  }
+
+  if(strcasecompare("pwd", cmd)) {
+    /* output debug output if that is requested */
+    char *tmp = aprintf("257 \"%s\" is current directory.\n",
+                        protop->path);
+    if(!tmp) {
+      sshc->actualcode = CURLE_OUT_OF_MEMORY;
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      return;
+    }
+    if(data->set.verbose) {
+      Curl_debug(data, CURLINFO_HEADER_OUT, (char *) "PWD\n", 4, conn);
+      Curl_debug(data, CURLINFO_HEADER_IN, tmp, strlen(tmp), conn);
+    }
+    /* this sends an FTP-like "header" to the header callback so that the
+       current directory can be read very similar to how it is read when
+       using ordinary FTP. */
+    result = Curl_client_write(conn, CLIENTWRITE_HEADER, tmp, strlen(tmp));
+    free(tmp);
+    if(result) {
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = result;
+    }
+    else
+      state(conn, SSH_SFTP_NEXT_QUOTE);
+    return;
+  }
+  if(cmd) {
+    /*
+     * the arguments following the command must be separated from the
+     * command with a space so we can check for it unconditionally
+     */
+    cp = strchr(cmd, ' ');
+    if(cp == NULL) {
+      failf(data, "Syntax error in SFTP command. Supply parameter(s)!");
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = CURLE_QUOTE_ERROR;
+      return;
+    }
+
+    /*
+     * also, every command takes at least one argument so we get that
+     * first argument right now
+     */
+    result = Curl_get_pathname(&cp, &sshc->quote_path1);
+    if(result) {
+      if(result == CURLE_OUT_OF_MEMORY)
+        failf(data, "Out of memory");
+      else
+        failf(data, "Syntax error: Bad first parameter");
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = result;
+      return;
+    }
+
+    /*
+     * SFTP is a binary protocol, so we don't send text commands
+     * to the server. Instead, we scan for commands used by
+     * OpenSSH's sftp program and call the appropriate libssh
+     * functions.
+     */
+    if(strncasecompare(cmd, "chgrp ", 6) ||
+        strncasecompare(cmd, "chmod ", 6) ||
+        strncasecompare(cmd, "chown ", 6)) {
+      /* attribute change */
+
+      /* sshc->quote_path1 contains the mode to set */
+      /* get the destination */
+      result = Curl_get_pathname(&cp, &sshc->quote_path2);
+      if(result) {
+        if(result == CURLE_OUT_OF_MEMORY)
+          failf(data, "Out of memory");
+        else
+          failf(data, "Syntax error in chgrp/chmod/chown: "
+                "Bad second parameter");
+        Curl_safefree(sshc->quote_path1);
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = result;
+        return;
+      }
+      sshc->quote_attrs = NULL;
+      state(conn, SSH_SFTP_QUOTE_STAT);
+      return;
+    }
+    if(strncasecompare(cmd, "ln ", 3) ||
+        strncasecompare(cmd, "symlink ", 8)) {
+      /* symbolic linking */
+      /* sshc->quote_path1 is the source */
+      /* get the destination */
+      result = Curl_get_pathname(&cp, &sshc->quote_path2);
+      if(result) {
+        if(result == CURLE_OUT_OF_MEMORY)
+          failf(data, "Out of memory");
+        else
+          failf(data, "Syntax error in ln/symlink: Bad second parameter");
+        Curl_safefree(sshc->quote_path1);
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = result;
+        return;
+      }
+      state(conn, SSH_SFTP_QUOTE_SYMLINK);
+      return;
+    }
+    else if(strncasecompare(cmd, "mkdir ", 6)) {
+      /* create dir */
+      state(conn, SSH_SFTP_QUOTE_MKDIR);
+      return;
+    }
+    else if(strncasecompare(cmd, "rename ", 7)) {
+      /* rename file */
+      /* first param is the source path */
+      /* second param is the dest. path */
+      result = Curl_get_pathname(&cp, &sshc->quote_path2);
+      if(result) {
+        if(result == CURLE_OUT_OF_MEMORY)
+          failf(data, "Out of memory");
+        else
+          failf(data, "Syntax error in rename: Bad second parameter");
+        Curl_safefree(sshc->quote_path1);
+        state(conn, SSH_SFTP_CLOSE);
+        sshc->nextstate = SSH_NO_STATE;
+        sshc->actualcode = result;
+        return;
+      }
+      state(conn, SSH_SFTP_QUOTE_RENAME);
+      return;
+    }
+    else if(strncasecompare(cmd, "rmdir ", 6)) {
+      /* delete dir */
+      state(conn, SSH_SFTP_QUOTE_RMDIR);
+      return;
+    }
+    else if(strncasecompare(cmd, "rm ", 3)) {
+      state(conn, SSH_SFTP_QUOTE_UNLINK);
+      return;
+    }
+#ifdef HAS_STATVFS_SUPPORT
+    else if(strncasecompare(cmd, "statvfs ", 8)) {
+      state(conn, SSH_SFTP_QUOTE_STATVFS);
+      return;
+    }
+#endif
+
+    failf(data, "Unknown SFTP command");
+    Curl_safefree(sshc->quote_path1);
+    Curl_safefree(sshc->quote_path2);
+    state(conn, SSH_SFTP_CLOSE);
+    sshc->nextstate = SSH_NO_STATE;
+    sshc->actualcode = CURLE_QUOTE_ERROR;
+    return;
+  }
+
+  if(!sshc->quote_item) {
+    state(conn, SSH_SFTP_GETINFO);
+  }
+}
+
+static void sftp_quote_stat(struct connectdata *conn)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssh_conn *sshc = &conn->proto.sshc;
+  char *cmd = sshc->quote_item->data;
+  sshc->acceptfail = FALSE;
+
+  /* if a command starts with an asterisk, which a legal SFTP command never
+     can, the command will be allowed to fail without it causing any
+     aborts or cancels etc. It will cause libcurl to act as if the command
+     is successful, whatever the server reponds. */
+
+  if(cmd[0] == '*') {
+    cmd++;
+    sshc->acceptfail = TRUE;
+  }
+
+  /* We read the file attributes, store them in sshc->quote_attrs
+   * and modify them accordingly to command. Then we switch to
+   * QUOTE_SETSTAT state to write new ones.
+   */
+
+  if(sshc->quote_attrs)
+    sftp_attributes_free(sshc->quote_attrs);
+  sshc->quote_attrs = sftp_stat(sshc->sftp_session, sshc->quote_path2);
+  if(sshc->quote_attrs == NULL) {
+    Curl_safefree(sshc->quote_path1);
+    Curl_safefree(sshc->quote_path2);
+    failf(data, "Attempt to get SFTP stats failed: %d",
+          sftp_get_error(sshc->sftp_session));
+    state(conn, SSH_SFTP_CLOSE);
+    sshc->nextstate = SSH_NO_STATE;
+    sshc->actualcode = CURLE_QUOTE_ERROR;
+    return;
+  }
+
+  /* Now set the new attributes... */
+  if(strncasecompare(cmd, "chgrp", 5)) {
+    sshc->quote_attrs->gid = (uint32_t)strtoul(sshc->quote_path1, NULL, 10);
+    if(sshc->quote_attrs->gid == 0 && !ISDIGIT(sshc->quote_path1[0]) &&
+        !sshc->acceptfail) {
+      Curl_safefree(sshc->quote_path1);
+      Curl_safefree(sshc->quote_path2);
+      failf(data, "Syntax error: chgrp gid not a number");
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = CURLE_QUOTE_ERROR;
+      return;
+    }
+    sshc->quote_attrs->flags |= SSH_FILEXFER_ATTR_UIDGID;
+  }
+  else if(strncasecompare(cmd, "chmod", 5)) {
+    mode_t perms;
+    perms = (mode_t)strtoul(sshc->quote_path1, NULL, 8);
+    /* permissions are octal */
+    if(perms == 0 && !ISDIGIT(sshc->quote_path1[0])) {
+      Curl_safefree(sshc->quote_path1);
+      Curl_safefree(sshc->quote_path2);
+      failf(data, "Syntax error: chmod permissions not a number");
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = CURLE_QUOTE_ERROR;
+      return;
+    }
+    sshc->quote_attrs->permissions = perms;
+    sshc->quote_attrs->flags |= SSH_FILEXFER_ATTR_PERMISSIONS;
+  }
+  else if(strncasecompare(cmd, "chown", 5)) {
+    sshc->quote_attrs->uid = (uint32_t)strtoul(sshc->quote_path1, NULL, 10);
+    if(sshc->quote_attrs->uid == 0 && !ISDIGIT(sshc->quote_path1[0]) &&
+        !sshc->acceptfail) {
+      Curl_safefree(sshc->quote_path1);
+      Curl_safefree(sshc->quote_path2);
+      failf(data, "Syntax error: chown uid not a number");
+      state(conn, SSH_SFTP_CLOSE);
+      sshc->nextstate = SSH_NO_STATE;
+      sshc->actualcode = CURLE_QUOTE_ERROR;
+      return;
+    }
+    sshc->quote_attrs->flags |= SSH_FILEXFER_ATTR_UIDGID;
+  }
+
+  /* Now send the completed structure... */
+  state(conn, SSH_SFTP_QUOTE_SETSTAT);
+  return;
+}
+
+
 #endif                          /* USE_LIBSSH */