Merge branch 'develop' into rav/saml_config_cleanup

2 files changed, 54 insertions, 40 deletions

diff --git a/docker/README.md b/docker/README.md
index 46bb9d2d99..d5879c2f2c 100644
--- a/docker/README.md
+++ b/docker/README.md
@@ -17,7 +17,7 @@ By default, the image expects a single volume, located at ``/data``, that will h
 * the appservices configuration.
 
 You are free to use separate volumes depending on storage endpoints at your
-disposal. For instance, ``/data/media`` coud be stored on a large but low
+disposal. For instance, ``/data/media`` could be stored on a large but low
 performance hdd storage while other files could be stored on high performance
 endpoints.
 
@@ -27,8 +27,8 @@ configuration file there. Multiple application services are supported.
 
 ## Generating a configuration file
 
-The first step is to genearte a valid config file. To do this, you can run the
-image with the `generate` commandline option.
+The first step is to generate a valid config file. To do this, you can run the
+image with the `generate` command line option.
 
 You will need to specify values for the `SYNAPSE_SERVER_NAME` and
 `SYNAPSE_REPORT_STATS` environment variable, and mount a docker volume to store
@@ -59,7 +59,7 @@ The following environment variables are supported in `generate` mode:
 * `SYNAPSE_CONFIG_PATH`: path to the file to be generated. Defaults to
   `<SYNAPSE_CONFIG_DIR>/homeserver.yaml`.
 * `SYNAPSE_DATA_DIR`: where the generated config will put persistent data
-  such as the datatase and media store. Defaults to `/data`.
+  such as the database and media store. Defaults to `/data`.
 * `UID`, `GID`: the user id and group id to use for creating the data
   directories. Defaults to `991`, `991`.
 
@@ -115,7 +115,7 @@ not given).
 
 To migrate from a dynamic configuration file to a static one, run the docker
 container once with the environment variables set, and `migrate_config`
-commandline option. For example:
+command line option. For example:
 
 ```
 docker run -it --rm \
diff --git a/docker/start.py b/docker/start.py
index 40a861f200..260f2d9943 100755
--- a/docker/start.py
+++ b/docker/start.py
@@ -41,8 +41,8 @@ def generate_config_from_template(config_dir, config_path, environ, ownership):
         config_dir (str): where to put generated config files
         config_path (str): where to put the main config file
         environ (dict): environment dictionary
-        ownership (str): "<user>:<group>" string which will be used to set
-            ownership of the generated configs
+        ownership (str|None): "<user>:<group>" string which will be used to set
+            ownership of the generated configs. If None, ownership will not change.
     """
     for v in ("SYNAPSE_SERVER_NAME", "SYNAPSE_REPORT_STATS"):
         if v not in environ:
@@ -105,24 +105,24 @@ def generate_config_from_template(config_dir, config_path, environ, ownership):
     log("Generating log config file " + log_config_file)
     convert("/conf/log.config", log_config_file, environ)
 
-    subprocess.check_output(["chown", "-R", ownership, "/data"])
-
     # Hopefully we already have a signing key, but generate one if not.
-    subprocess.check_output(
-        [
-            "su-exec",
-            ownership,
-            "python",
-            "-m",
-            "synapse.app.homeserver",
-            "--config-path",
-            config_path,
-            # tell synapse to put generated keys in /data rather than /compiled
-            "--keys-directory",
-            config_dir,
-            "--generate-keys",
-        ]
-    )
+    args = [
+        "python",
+        "-m",
+        "synapse.app.homeserver",
+        "--config-path",
+        config_path,
+        # tell synapse to put generated keys in /data rather than /compiled
+        "--keys-directory",
+        config_dir,
+        "--generate-keys",
+    ]
+
+    if ownership is not None:
+        subprocess.check_output(["chown", "-R", ownership, "/data"])
+        args = ["su-exec", ownership] + args
+
+    subprocess.check_output(args)
 
 
 def run_generate_config(environ, ownership):
@@ -130,7 +130,7 @@ def run_generate_config(environ, ownership):
 
     Args:
         environ (dict): env var dict
-        ownership (str): "userid:groupid" arg for chmod
+        ownership (str|None): "userid:groupid" arg for chmod. If None, ownership will not change.
 
     Never returns.
     """
@@ -149,9 +149,6 @@ def run_generate_config(environ, ownership):
         log("Creating log config %s" % (log_config_file,))
         convert("/conf/log.config", log_config_file, environ)
 
-    # make sure that synapse has perms to write to the data dir.
-    subprocess.check_output(["chown", ownership, data_dir])
-
     args = [
         "python",
         "-m",
@@ -170,12 +167,33 @@ def run_generate_config(environ, ownership):
         "--open-private-ports",
     ]
     # log("running %s" % (args, ))
-    os.execv("/usr/local/bin/python", args)
+
+    if ownership is not None:
+        args = ["su-exec", ownership] + args
+        os.execv("/sbin/su-exec", args)
+
+        # make sure that synapse has perms to write to the data dir.
+        subprocess.check_output(["chown", ownership, data_dir])
+    else:
+        os.execv("/usr/local/bin/python", args)
 
 
 def main(args, environ):
     mode = args[1] if len(args) > 1 else None
-    ownership = "{}:{}".format(environ.get("UID", 991), environ.get("GID", 991))
+    desired_uid = int(environ.get("UID", "991"))
+    desired_gid = int(environ.get("GID", "991"))
+    if (desired_uid == os.getuid()) and (desired_gid == os.getgid()):
+        ownership = None
+    else:
+        ownership = "{}:{}".format(desired_uid, desired_gid)
+
+    log(
+        "Container running as UserID %s:%s, ENV (or defaults) requests %s:%s"
+        % (os.getuid(), os.getgid(), desired_uid, desired_gid)
+    )
+
+    if ownership is None:
+        log("Will not perform chmod/su-exec as UserID already matches request")
 
     # In generate mode, generate a configuration and missing keys, then exit
     if mode == "generate":
@@ -227,16 +245,12 @@ def main(args, environ):
 
     log("Starting synapse with config file " + config_path)
 
-    args = [
-        "su-exec",
-        ownership,
-        "python",
-        "-m",
-        "synapse.app.homeserver",
-        "--config-path",
-        config_path,
-    ]
-    os.execv("/sbin/su-exec", args)
+    args = ["python", "-m", "synapse.app.homeserver", "--config-path", config_path]
+    if ownership is not None:
+        args = ["su-exec", ownership] + args
+        os.execv("/sbin/su-exec", args)
+    else:
+        os.execv("/usr/local/bin/python", args)
 
 
 if __name__ == "__main__":