do not set O_TRUNC when opening destination file.

It prevents `mscp localhost:hoge ~/hoge` from truncating the source
file. See https://bugzilla.mindrot.org/show_bug.cgi?id=3431.

https://github.com/upa/mscp/issues/1

4 files changed, 33 insertions, 8 deletions

diff --git a/src/fileops.c b/src/fileops.c
index 994dd77..d9587ef 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -293,15 +293,24 @@ int mscp_lseek(mf *f, size_t off)
 	return ret;
 }
 
-int mscp_chmod(const char *path, mode_t mode, sftp_session sftp)
+int mscp_setstat(const char *path, mode_t mode, size_t size, sftp_session sftp)
 {
 	int ret;
 
 	if (sftp) {
-		ret = sftp_chmod(sftp, path, mode);
+		struct sftp_attributes_struct attr;
+		memset(&attr, 0, sizeof(attr));
+		attr.permissions = mode;
+		attr.size = size;
+		attr.flags = (SSH_FILEXFER_ATTR_PERMISSIONS|SSH_FILEXFER_ATTR_SIZE);
+		ret = sftp_setstat(sftp, path, &attr);
 		sftp_err_to_errno(sftp);
-	} else
-		ret = chmod(path, mode);
+	} else {
+		if ((ret = chmod(path, mode)) < 0)
+			return ret;
+		if ((ret = truncate(path, size)) < 0)
+			return ret;
+	}
 
 	return ret;
 }
diff --git a/src/fileops.h b/src/fileops.h
index ede9c48..8dc6e5b 100644
--- a/src/fileops.h
+++ b/src/fileops.h
@@ -46,7 +46,11 @@ typedef struct mf_struct mf;
 mf *mscp_open(const char *path, int flags, mode_t mode, sftp_session sftp);
 void mscp_close(mf *f);
 int mscp_lseek(mf *f, size_t off);
-int mscp_chmod(const char *path, mode_t mode, sftp_session sftp);
+
+/* mscp_setstat() involves chmod and truncate. It executes both at
+ * once via a single SFTP command (sftp_setstat()).
+ */
+int mscp_setstat(const char *path, mode_t mode, size_t size, sftp_session sftp);
 
 /* remote glob */
 int mscp_glob(const char *pattern, int flags, glob_t *pglob, sftp_session sftp);
diff --git a/src/path.c b/src/path.c
index e35ff06..254f8c3 100644
--- a/src/path.c
+++ b/src/path.c
@@ -334,8 +334,9 @@ static int touch_dst_path(struct path *p, sftp_session sftp)
                 *needle = '/';
         }
 
-        /* open file with O_TRUNC to set file size 0 */
-	f = mscp_open(p->dst_path, O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR, sftp);
+	/* Do not set O_TRUNC here. Instead, do mscp_setstat() at the
+	 * end. see https://bugzilla.mindrot.org/show_bug.cgi?id=3431 */
+	f = mscp_open(p->dst_path, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR, sftp);
 	if (!f) {
 		mscp_set_error("mscp_open %s: %s\n", p->dst_path, strerrno());
 		return -1;
@@ -574,7 +575,9 @@ int copy_chunk(FILE *msg_fp, struct chunk *c,
 
 	if (refcnt_dec(&c->p->refcnt) == 0) {
 		c->p->state = FILE_STATE_DONE;
-		mscp_chmod(c->p->dst_path, c->p->mode, dst_sftp);
+		if (mscp_setstat(c->p->dst_path, c->p->mode, c->p->size, dst_sftp) < 0)
+			mpr_err(msg_fp, "failed to chmod and truncate %s: %s\n",
+				c->p->path, strerrno());
 		mpr_info(msg_fp, "copy done: %s\n", c->p->path);
 	}
 
diff --git a/test/test_e2e.py b/test/test_e2e.py
index 841c3be..c63a09e 100644
--- a/test/test_e2e.py
+++ b/test/test_e2e.py
@@ -227,6 +227,15 @@ def test_override_dst_having_larger_size(mscp, src_prefix, dst_prefix):
     src.cleanup()
     dst.cleanup()
 
+@pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
+def test_dont_truncate_dst(mscp, src_prefix, dst_prefix):
+    f = File("srcanddst", size = 1024 * 1024 * 128).make()
+    md5_before = f.md5sum()
+    run2ok([mscp, "-H", "-vvv", src_prefix + f.path, dst_prefix + f.path])
+    md5_after = f.md5sum()
+    assert md5_before == md5_after
+    f.cleanup()
+
 compressions = ["yes", "no", "none"]
 @pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
 @pytest.mark.parametrize("compress", compressions)