Support transfering empty files to target host. Fixes #36725 (#45751)

changelogs/fragments/dd-put-empty-files.yaml

@@ -0,0 +1,7 @@
+bugfixes:
+- docker connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)
+- chroot connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)
+- jail connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)
+- kubectl connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)
+- libvirt_lxc connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)
+- zone connection - Support empty files with copying to target (https://github.com/ansible/ansible/issues/36725)

lib/ansible/plugins/connection/chroot.py

@@ -148,8 +148,12 @@ class Connection(ConnectionBase):
         out_path = shlex_quote(self._prefix_login_path(out_path))
         try:
             with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+                if not os.fstat(in_file.fileno()).st_size:
+                    count = ' count=0'
+                else:
+                    count = ''
                 try:
-                    p = self._buffered_exec_command('dd of=%s bs=%s' % (out_path, BUFSIZE), stdin=in_file)
+                    p = self._buffered_exec_command('dd of=%s bs=%s%s' % (out_path, BUFSIZE, count), stdin=in_file)
                 except OSError:
                     raise AnsibleError("chroot connection requires dd command in the chroot")
                 try:

lib/ansible/plugins/connection/docker.py

@@ -246,9 +246,13 @@ class Connection(ConnectionBase):
         # running containers, so we use docker exec to implement this
         # Although docker version 1.8 and later provide support, the
         # owner and group of the files are always set to root
-        args = self._build_exec_cmd([self._play_context.executable, "-c", "dd of=%s bs=%s" % (out_path, BUFSIZE)])
-        args = [to_bytes(i, errors='surrogate_or_strict') for i in args]
         with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+            if not os.fstat(in_file.fileno()).st_size:
+                count = ' count=0'
+            else:
+                count = ''
+            args = self._build_exec_cmd([self._play_context.executable, "-c", "dd of=%s bs=%s%s" % (out_path, BUFSIZE, count)])
+            args = [to_bytes(i, errors='surrogate_or_strict') for i in args]
             try:
                 p = subprocess.Popen(args, stdin=in_file,
                                      stdout=subprocess.PIPE, stderr=subprocess.PIPE)

lib/ansible/plugins/connection/jail.py

@@ -158,8 +158,12 @@ class Connection(ConnectionBase):
         out_path = shlex_quote(self._prefix_login_path(out_path))
         try:
             with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+                if not os.fstat(in_file.fileno()).st_size:
+                    count = ' count=0'
+                else:
+                    count = ''
                 try:
-                    p = self._buffered_exec_command('dd of=%s bs=%s' % (out_path, BUFSIZE), stdin=in_file)
+                    p = self._buffered_exec_command('dd of=%s bs=%s%s' % (out_path, BUFSIZE, count), stdin=in_file)
                 except OSError:
                     raise AnsibleError("jail connection requires dd command in the jail")
                 try:

lib/ansible/plugins/connection/kubectl.py

@@ -300,9 +300,13 @@ class Connection(ConnectionBase):
         out_path = shlex_quote(out_path)
         # kubectl doesn't have native support for copying files into
         # running containers, so we use kubectl exec to implement this
-        args = self._build_exec_cmd([self._play_context.executable, "-c", "dd of=%s bs=%s" % (out_path, BUFSIZE)])
-        args = [to_bytes(i, errors='surrogate_or_strict') for i in args]
         with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+            if not os.fstat(in_file.fileno()).st_size:
+                count = ' count=0'
+            else:
+                count = ''
+            args = self._build_exec_cmd([self._play_context.executable, "-c", "dd of=%s bs=%s%s" % (out_path, BUFSIZE, count)])
+            args = [to_bytes(i, errors='surrogate_or_strict') for i in args]
             try:
                 p = subprocess.Popen(args, stdin=in_file,
                                      stdout=subprocess.PIPE, stderr=subprocess.PIPE)

lib/ansible/plugins/connection/libvirt_lxc.py

@@ -138,8 +138,12 @@ class Connection(ConnectionBase):
         out_path = shlex_quote(self._prefix_login_path(out_path))
         try:
             with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+                if not os.fstat(in_file.fileno()).st_size:
+                    count = ' count=0'
+                else:
+                    count = ''
                 try:
-                    p = self._buffered_exec_command('dd of=%s bs=%s' % (out_path, BUFSIZE), stdin=in_file)
+                    p = self._buffered_exec_command('dd of=%s bs=%s%s' % (out_path, BUFSIZE, count), stdin=in_file)
                 except OSError:
                     raise AnsibleError("chroot connection requires dd command in the chroot")
                 try:

lib/ansible/plugins/connection/zone.py

@@ -157,8 +157,12 @@ class Connection(ConnectionBase):
         out_path = shlex_quote(self._prefix_login_path(out_path))
         try:
             with open(in_path, 'rb') as in_file:
+                if not os.fstat(in_file.fileno()).st_size:
+                    count = ' count=0'
+                else:
+                    count = ''
                 try:
-                    p = self._buffered_exec_command('dd of=%s bs=%s' % (out_path, BUFSIZE), stdin=in_file)
+                    p = self._buffered_exec_command('dd of=%s bs=%s%s' % (out_path, BUFSIZE, count), stdin=in_file)
                 except OSError:
                     raise AnsibleError("jail connection requires dd command in the jail")
                 try: