On Wed, 13 Sep 2017 14:54:43 -0700
Brandon Williams <bmw...@google.com> wrote:
> A normal request to git-daemon is structured as
> "command path/to/repo\0host=..\0" and due to a bug in an old version of
> git-daemon 73bb33a94 (daemon: Strictly parse the "extra arg" part of the
> command, 2009-06-04) we aren't able to place any extra args (separated
> by NULs) besides the host.
>
> In order to get around this limitation teach git-daemon to recognize
> additional request arguments hidden behind a second NUL byte. Requests
> can then be structured like:
> "command path/to/repo\0host=..\0\0version=1\0key=value\0". git-daemon
> can then parse out the extra arguments and set 'GIT_PROTOCOL'
> accordingly.
A test in this patch (if possible) would be nice, but it is probably
clearer to test this when one of the commands (e.g. upload-pack) is
done. Could a test be added to the next patch to verify (using
GIT_TRACE_PACKET, maybe) that the expected strings are sent? Then
mention in this commit message that this will be tested in the next
patch too.
> @@ -574,7 +583,7 @@ static void canonicalize_client(struct strbuf *out, const
> char *in)
> /*
> * Read the host as supplied by the client connection.
> */
> -static void parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
> +static char *parse_host_arg(struct hostinfo *hi, char *extra_args, int
> buflen)
> {
> char *val;
> int vallen;
> @@ -602,6 +611,39 @@ static void parse_host_arg(struct hostinfo *hi, char
> *extra_args, int buflen)
> if (extra_args < end && *extra_args)
> die("Invalid request");
> }
> +
> + return extra_args;
> +}
> +
> +static void parse_extra_args(struct argv_array *env, const char *extra_args,
> + int buflen)
> +{
> + const char *end = extra_args + buflen;
> + struct strbuf git_protocol = STRBUF_INIT;
> +
> + for (; extra_args < end; extra_args += strlen(extra_args) + 1) {
> + const char *arg = extra_args;
> +
> + /*
> + * Parse the extra arguments, adding most to 'git_protocol'
> + * which will be used to set the 'GIT_PROTOCOL' envvar in the
> + * service that will be run.
> + *
> + * If there ends up being a particular arg in the future that
> + * git-daemon needs to parse specificly (like the 'host' arg)
> + * then it can be parsed here and not added to 'git_protocol'.
> + */
> + if (*arg) {
> + if (git_protocol.len > 0)
> + strbuf_addch(&git_protocol, ':');
> + strbuf_addstr(&git_protocol, arg);
> + }
> + }
> +
> + if (git_protocol.len > 0)
> + argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s",
> + git_protocol.buf);
> + strbuf_release(&git_protocol);
> }
I would rewrite this with parse_extra_args() calling parse_host_arg()
instead (right now, you have 2 functions with 2 different meanings of
"extra_args"). If you want to keep this arrangement, though, add a
documentation comment about the meaning of the return value of
parse_host_arg().
