- djm@cvs.openbsd.org 2013/07/25 00:56:52

     [sftp-client.c sftp-client.h sftp.1 sftp.c]
     sftp support for resuming partial downloads; patch mostly by Loganaden
     Velvindron/AfriNIC with some tweaks by me; feedback and ok dtucker@

1 files changed, 52 insertions, 23 deletions

diff --git a/sftp-client.c b/sftp-client.c
index ab035c713..cb4efd3ea 100644
--- a/sftp-client.c
+++ b/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.100 2013/06/01 22:34:50 dtucker Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.101 2013/07/25 00:56:51 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -112,7 +112,7 @@ send_msg(struct sftp_conn *conn, Buffer *m)
         iov[1].iov_len = buffer_len(m);
 
         if (atomiciov6(writev, conn->fd_out, iov, 2,
-            conn->limit_kbps > 0 ? sftpio : NULL, &conn->bwlimit_out) != 
+            conn->limit_kbps > 0 ? sftpio : NULL, &conn->bwlimit_out) !=
             buffer_len(m) + sizeof(mlen))
                 fatal("Couldn't send packet: %s", strerror(errno));
 
@@ -988,16 +988,17 @@ send_read_request(struct sftp_conn *conn, u_int id, u_int64_t offset,
 
 int
 do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
-    Attrib *a, int pflag)
+    Attrib *a, int pflag, int resume)
 {
         Attrib junk;
         Buffer msg;
         char *handle;
-        int local_fd, status = 0, write_error;
-        int read_error, write_errno;
-        u_int64_t offset, size;
+        int local_fd = -1, status = 0, write_error;
+        int read_error, write_errno, reordered = 0;
+        u_int64_t offset = 0, size, highwater;
         u_int handle_len, mode, type, id, buflen, num_req, max_req;
         off_t progress_counter;
+        struct stat st;
         struct request {
                 u_int id;
                 u_int len;
@@ -1050,21 +1051,36 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
                 return(-1);
         }
 
-        local_fd = open(local_path, O_WRONLY | O_CREAT | O_TRUNC,
+        local_fd = open(local_path, O_WRONLY | O_CREAT | (resume ? : O_TRUNC),
             mode | S_IWUSR);
         if (local_fd == -1) {
                 error("Couldn't open local file \"%s\" for writing: %s",
                     local_path, strerror(errno));
-                do_close(conn, handle, handle_len);
-                buffer_free(&msg);
-                free(handle);
-                return(-1);
+                goto fail;
+        }
+        offset = highwater = 0;
+        if (resume) {
+                if (fstat(local_fd, &st) == -1) {
+                        error("Unable to stat local file \"%s\": %s",
+                            local_path, strerror(errno));
+                        goto fail;
+                }
+                if ((size_t)st.st_size > size) {
+                        error("Unable to resume download of \"%s\": "
+                            "local file is larger than remote", local_path);
+ fail:
+                        do_close(conn, handle, handle_len);
+                        buffer_free(&msg);
+                        free(handle);
+                        return -1;
+                }
+                offset = highwater = st.st_size;
         }
 
         /* Read from remote and write to local */
-        write_error = read_error = write_errno = num_req = offset = 0;
+        write_error = read_error = write_errno = num_req = 0;
         max_req = 1;
-        progress_counter = 0;
+        progress_counter = offset;
 
         if (showprogress && size != 0)
                 start_progress_meter(remote_path, size, &progress_counter);
@@ -1139,6 +1155,10 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
                                 write_error = 1;
                                 max_req = 0;
                         }
+                        else if (!reordered && req->offset <= highwater)
+                                highwater = req->offset + len;
+                        else if (!reordered && req->offset > highwater)
+                                reordered = 1;
                         progress_counter += len;
                         free(data);
 
@@ -1187,7 +1207,15 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
         /* Sanity check */
         if (TAILQ_FIRST(&requests) != NULL)
                 fatal("Transfer complete, but requests still in queue");
-
+        /* Truncate at highest contiguous point to avoid holes on interrupt */
+        if (read_error || write_error || interrupted) {
+                if (reordered && resume) {
+                        error("Unable to resume download of \"%s\": "
+                            "server reordered requests", local_path);
+                }
+                debug("truncating at %llu", (unsigned long long)highwater);
+                ftruncate(local_fd, highwater);
+        }
         if (read_error) {
                 error("Couldn't read from remote file \"%s\" : %s",
                     remote_path, fx2txt(status));
@@ -1199,7 +1227,8 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
                 do_close(conn, handle, handle_len);
         } else {
                 status = do_close(conn, handle, handle_len);
-
+                if (interrupted)
+                        status = -1;
                 /* Override umask and utimes if asked */
 #ifdef HAVE_FCHMOD
                 if (pflag && fchmod(local_fd, mode) == -1)
@@ -1227,7 +1256,7 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 
 static int
 download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
-    Attrib *dirattrib, int pflag, int printflag, int depth)
+    Attrib *dirattrib, int pflag, int printflag, int depth, int resume)
 {
         int i, ret = 0;
         SFTP_DIRENT **dir_entries;
@@ -1280,11 +1309,11 @@ download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
                                 continue;
                         if (download_dir_internal(conn, new_src, new_dst,
                             &(dir_entries[i]->a), pflag, printflag,
-                            depth + 1) == -1)
+                            depth + 1, resume) == -1)
                                 ret = -1;
                 } else if (S_ISREG(dir_entries[i]->a.perm) ) {
                         if (do_download(conn, new_src, new_dst,
-                            &(dir_entries[i]->a), pflag) == -1) {
+                            &(dir_entries[i]->a), pflag, resume) == -1) {
                                 error("Download of file %s to %s failed",
                                     new_src, new_dst);
                                 ret = -1;
@@ -1317,7 +1346,7 @@ download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 
 int
 download_dir(struct sftp_conn *conn, char *src, char *dst,
-    Attrib *dirattrib, int pflag, int printflag)
+    Attrib *dirattrib, int pflag, int printflag, int resume)
 {
         char *src_canon;
         int ret;
@@ -1328,7 +1357,7 @@ download_dir(struct sftp_conn *conn, char *src, char *dst,
         }
 
         ret = download_dir_internal(conn, src_canon, dst,
-            dirattrib, pflag, printflag, 0);
+            dirattrib, pflag, printflag, 0, resume);
         free(src_canon);
         return ret;
 }
@@ -1553,7 +1582,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
         a.perm &= 01777;
         if (!pflag)
                 a.flags &= ~SSH2_FILEXFER_ATTR_ACMODTIME;
-        
+
         status = do_mkdir(conn, dst, &a, 0);
         /*
          * we lack a portable status for errno EEXIST,
@@ -1563,7 +1592,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
         if (status != SSH2_FX_OK) {
                 if (status != SSH2_FX_FAILURE)
                         return -1;
-                if (do_stat(conn, dst, 0) == NULL) 
+                if (do_stat(conn, dst, 0) == NULL)
                         return -1;
         }
 
@@ -1571,7 +1600,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
                 error("Failed to open dir \"%s\": %s", src, strerror(errno));
                 return -1;
         }
-        
+
         while (((dp = readdir(dirp)) != NULL) && !interrupted) {
                 if (dp->d_ino == 0)
                         continue;