flexnbd: Split the proxy mode out into its own binary.

"flexnbd-proxy ..." should be identical in operation to "flexnbd proxy ..."

src/proxy-main.c

@@ -0,0 +1,172 @@
+#include <signal.h>
+#include <sys/signalfd.h>
+
+#include "mode.h"
+#include "util.h"
+#include "sockutil.h"
+#include "proxy.h"
+
+
+static struct option proxy_options[] = {
+	GETOPT_HELP,
+	GETOPT_ADDR,
+	GETOPT_PORT,
+	GETOPT_CONNECT_ADDR,
+	GETOPT_CONNECT_PORT,
+	GETOPT_BIND,
+	GETOPT_QUIET,
+	GETOPT_VERBOSE,
+	{0}
+};
+static char proxy_short_options[] = "hl:p:C:P:b:" SOPT_QUIET SOPT_VERBOSE;
+static char proxy_help_text[] =
+	"Usage: flexnbd-proxy <options>\n\n"
+	"Resiliently proxy an NBD connection between client and server\n\n"
+	HELP_LINE
+	"\t--" OPT_ADDR ",-l <ADDR>\tThe address we will bind to as a proxy.\n"
+	"\t--" OPT_PORT ",-p <PORT>\tThe port we will bind to as a proxy.\n"
+	"\t--" OPT_CONNECT_ADDR ",-C <ADDR>\tAddress of the proxied server.\n"
+	"\t--" OPT_CONNECT_PORT ",-P <PORT>\tPort of the proxied server.\n"
+	"\t--" OPT_BIND ",-b <ADDR>\tThe address we connect from, as a proxy.\n"
+	QUIET_LINE
+	VERBOSE_LINE;
+
+void read_proxy_param(
+			int c,
+			char **downstream_addr,
+			char **downstream_port,
+			char **upstream_addr,
+			char **upstream_port,
+			char **bind_addr )
+{
+	switch( c ) {
+		case 'h' :
+			fprintf( stdout, "%s\n", proxy_help_text );
+			exit( 0 );
+			break;
+		case 'l':
+			*downstream_addr = optarg;
+			break;
+		case 'p':
+			*downstream_port = optarg;
+			break;
+		case 'C':
+			*upstream_addr = optarg;
+			break;
+		case 'P':
+			*upstream_port = optarg;
+			break;
+		case 'b':
+			*bind_addr = optarg;
+			break;
+		case 'q':
+			log_level = QUIET_LOG_LEVEL;
+			break;
+		case 'v':
+			log_level = VERBOSE_LOG_LEVEL;
+			break;
+		default:
+			exit_err( proxy_help_text );
+			break;
+	}
+}
+
+/* Stolen from flexnbd.c, wil change in the near future so no point DRYing */
+int build_signal_fd(void)
+{
+	sigset_t mask;
+	int sfd;
+
+	sigemptyset( &mask );
+	sigaddset( &mask, SIGTERM );
+	sigaddset( &mask, SIGQUIT );
+	sigaddset( &mask, SIGINT );
+
+	FATAL_UNLESS( 0 == pthread_sigmask( SIG_BLOCK, &mask, NULL ),
+			"Signal blocking failed" );
+
+	sfd = signalfd( -1, &mask, 0 );
+	FATAL_IF( -1 == sfd, "Failed to get a signal fd" );
+
+	return sfd;
+}
+
+struct proxier* flexnbd_create_proxying(
+	int signal_fd,
+	char* s_downstream_address,
+	char* s_downstream_port,
+	char* s_upstream_address,
+	char* s_upstream_port,
+	char* s_upstream_bind
+)
+{
+	struct proxier* proxy =  proxy_create(
+		signal_fd,
+		s_downstream_address,
+		s_downstream_port,
+		s_upstream_address,
+		s_upstream_port,
+		s_upstream_bind
+	);
+
+	return proxy;
+}
+
+
+int main( int argc, char *argv[] )
+{
+	int c;
+	struct proxier * proxy;
+	char *downstream_addr = NULL;
+	char *downstream_port = NULL;
+	char *upstream_addr   = NULL;
+	char *upstream_port   = NULL;
+	char *bind_addr       = NULL;
+	int signal_fd;
+	int success;
+
+	signal(SIGPIPE, SIG_IGN); /* calls to splice() unhelpfully throw this */
+	error_init();
+
+	while (1) {
+		c = getopt_long( argc, argv, proxy_short_options, proxy_options, NULL );
+		if ( -1 == c ) { break; }
+		read_proxy_param( c,
+				&downstream_addr,
+				&downstream_port,
+				&upstream_addr,
+				&upstream_port,
+				&bind_addr
+		);
+	}
+
+	if ( NULL == downstream_addr || NULL == downstream_port ){
+		fprintf( stderr, "both --addr and --port are required.\n" );
+		exit_err( proxy_help_text );
+	} else if ( NULL == upstream_addr || NULL == upstream_port ){
+		fprintf( stderr, "both --conn-addr and --conn-port are required.\n" );
+		exit_err( proxy_help_text );
+	}
+
+	signal_fd = build_signal_fd();
+
+	proxy = flexnbd_create_proxying(
+		signal_fd,
+		downstream_addr,
+		downstream_port,
+		upstream_addr,
+		upstream_port,
+		bind_addr
+	);
+
+	info(
+		"Proxying between %s %s (downstream) and %s %s (upstream)",
+		downstream_addr, downstream_port, upstream_addr, upstream_port
+	);
+
+    success = do_proxy( proxy );
+    sock_try_close( signal_fd );
+
+	return success ? 0 : 1;
+}
+