[PATCH v2 08/15] pesto: Add command line option parsing and debug messages

[David Gibson <david@gibson.dropbear.id.au>]

Add basic command line option parsing using getopt_long() to pesto.
Implement --help, --version, --quiet and --verbose options, along with a
debug() macro to print debugging messages when given the verbose option.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 common.h |  8 ++++++
 conf.c   | 45 +++++++++++++++++----------------
 passt.h  | 12 ++++-----
 pesto.c  | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++------
 util.h   |  8 ------
 5 files changed, 108 insertions(+), 42 deletions(-)

diff --git a/common.h b/common.h
index 76a95609..927d20a4 100644
--- a/common.h
+++ b/common.h
@@ -8,6 +8,14 @@
 #ifndef COMMON_H
 #define COMMON_H
 
+#define VERSION_BLOB							       \
+	VERSION "\n"							       \
+	"Copyright Red Hat\n"						       \
+	"GNU General Public License, version 2 or later\n"		       \
+	"  <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>\n"	       \
+	"This is free software: you are free to change and redistribute it.\n" \
+	"There is NO WARRANTY, to the extent permitted by law.\n\n"
+
 /* FPRINTF() intentionally silences cert-err33-c clang-tidy warnings */
 #define FPRINTF(f, ...)	(void)fprintf(f, __VA_ARGS__)
 
diff --git a/conf.c b/conf.c
index 031de352..e862b023 100644
--- a/conf.c
+++ b/conf.c
@@ -1146,6 +1146,9 @@ static void conf_print(const struct ctx *c)
 	char bufmac[ETH_ADDRSTRLEN], ifn[IFNAMSIZ];
 	int i;
 
+	if (c->fd_control_listen >= 0)
+		info("Configuration socket: %s", c->control_path);
+
 	if (c->ifi4 > 0 || c->ifi6 > 0) {
 		info("Template interface: %s%s%s%s%s",
 		     c->ifi4 > 0 ? if_indextoname(c->ifi4, ifn) : "",
@@ -1433,15 +1436,15 @@ static void conf_open_files(struct ctx *c)
 			die_perror("Couldn't open PID file %s", c->pidfile);
 	}
 
-	c->fd_conf = -1;
-	if (*c->conf_path) {
-		c->fd_conf_listen = sock_unix(c->conf_path);
-		if (c->fd_conf_listen < 0) {
+	c->fd_control = -1;
+	if (*c->control_path) {
+		c->fd_control_listen = sock_unix(c->control_path);
+		if (c->fd_control_listen < 0) {
 			die_perror("Couldn't open control socket %s",
-				   c->conf_path);
+				   c->control_path);
 		}
 	} else {
-		c->fd_conf_listen = -1;
+		c->fd_control_listen = -1;
 	}
 }
 
@@ -1486,13 +1489,13 @@ static void conf_sock_listen(const struct ctx *c)
 {
 	union epoll_ref ref = { .type = EPOLL_TYPE_CONF_LISTEN };
 
-	if (c->fd_conf_listen < 0)
+	if (c->fd_control_listen < 0)
 		return;
 
-	if (listen(c->fd_conf_listen, 0))
+	if (listen(c->fd_control_listen, 0))
 		die_perror("Couldn't listen on configuration socket");
 
-	ref.fd = c->fd_conf_listen;
+	ref.fd = c->fd_control_listen;
 	if (epoll_add(c->epollfd, EPOLLIN | EPOLLET, ref))
 		die_perror("Couldn't add configuration socket to epoll");
 }
@@ -1847,11 +1850,11 @@ void conf(struct ctx *c, int argc, char **argv)
 			c->fd_tap = -1;
 			break;
 		case 'c':
-			ret = snprintf(c->conf_path, sizeof(c->conf_path), "%s",
-				       optarg);
+			ret = snprintf(c->control_path, sizeof(c->control_path),
+				       "%s", optarg);
 			if (ret <= 0 || ret >= (int)sizeof(c->sock_path))
 				die("Invalid configuration path: %s", optarg);
-			c->fd_conf_listen = c->fd_conf = -1;
+			c->fd_control_listen = c->fd_control = -1;
 			break;
 		case 'F':
 			errno = 0;
@@ -2295,10 +2298,10 @@ void conf(struct ctx *c, int argc, char **argv)
 					FWD_SCAN);
 	}
 
+	conf_sock_listen(c);
+
 	if (!c->quiet)
 		conf_print(c);
-
-	conf_sock_listen(c);
 }
 
 /**
@@ -2322,7 +2325,7 @@ void conf_listen_handler(struct ctx *c, uint32_t events)
 		return;
 	}
 
-	fd = accept4(c->fd_conf_listen, NULL, NULL, SOCK_NONBLOCK);
+	fd = accept4(c->fd_control_listen, NULL, NULL, SOCK_NONBLOCK);
 	if (fd < 0) {
 		warn_perror("accept4() on configuration listening socket");
 		return;
@@ -2332,7 +2335,7 @@ void conf_listen_handler(struct ctx *c, uint32_t events)
 		warn_perror("Can't get configuration client credentials");
 
 	/* Another client is already connected: accept and close right away. */
-	if (c->fd_conf != -1) {
+	if (c->fd_control != -1) {
 		info("Discarding configuration client, PID %i", uc.pid);
 		goto fail;
 	}
@@ -2350,7 +2353,7 @@ void conf_listen_handler(struct ctx *c, uint32_t events)
 		goto fail;
 	}
 
-	c->fd_conf = fd;
+	c->fd_control = fd;
 	info("Accepted configuration client, PID %i", uc.pid);
 	if (!PESTO_PROTOCOL_VERSION) {
 		warn(
@@ -2375,7 +2378,7 @@ void conf_handler(struct ctx *c, uint32_t events)
 		ssize_t n;
 
 		do {
-			n = read(c->fd_conf, discard, sizeof(discard));
+			n = read(c->fd_control, discard, sizeof(discard));
 			if (n > 0)
 				debug("Discarded %zd bytes of config data", n);
 		} while (n > 0);
@@ -2398,7 +2401,7 @@ void conf_handler(struct ctx *c, uint32_t events)
 
 close:
 	debug("Closing configuration socket");
-	epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_conf, NULL);
-	close(c->fd_conf);
-	c->fd_conf = -1;
+	epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_control, NULL);
+	close(c->fd_control);
+	c->fd_control = -1;
 }
diff --git a/passt.h b/passt.h
index 6bb748fb..4245c4c8 100644
--- a/passt.h
+++ b/passt.h
@@ -158,7 +158,7 @@ struct ip6_ctx {
  * @foreground:		Run in foreground, don't log to stderr by default
  * @nofile:		Maximum number of open files (ulimit -n)
  * @sock_path:		Path for UNIX domain socket
- * @conf_path:		Path for configuration UNIX domain socket
+ * @control_path:	Path for control/configuration UNIX domain socket
  * @repair_path:	TCP_REPAIR helper path, can be "none", empty for default
  * @pcap:		Path for packet capture file
  * @pidfile:		Path to PID file, empty string if not configured
@@ -170,8 +170,8 @@ struct ip6_ctx {
  * @epollfd:		File descriptor for epoll instance
  * @fd_tap_listen:	File descriptor for listening AF_UNIX socket, if any
  * @fd_tap:		AF_UNIX socket, tuntap device, or pre-opened socket
- * @fd_conf_listen:	Listening configuration socket, if any
- * @fd_conf:		Configuration socket, if any
+ * @fd_control_listen:	Listening control/configuration socket, if any
+ * @fd_control:		Control/configuration socket, if any
  * @fd_repair_listen:	File descriptor for listening TCP_REPAIR socket, if any
  * @fd_repair:		Connected AF_UNIX socket for TCP_REPAIR helper
  * @our_tap_mac:	Pasta/passt's MAC on the tap link
@@ -227,7 +227,7 @@ struct ctx {
 	int foreground;
 	int nofile;
 	char sock_path[UNIX_PATH_MAX];
-	char conf_path[UNIX_PATH_MAX];
+	char control_path[UNIX_PATH_MAX];
 	char repair_path[UNIX_PATH_MAX];
 	char pcap[PATH_MAX];
 
@@ -245,8 +245,8 @@ struct ctx {
 	int epollfd;
 	int fd_tap_listen;
 	int fd_tap;
-	int fd_conf_listen;
-	int fd_conf;
+	int fd_control_listen;
+	int fd_control;
 	int fd_repair_listen;
 	int fd_repair;
 	unsigned char our_tap_mac[ETH_ALEN];
diff --git a/pesto.c b/pesto.c
index edc07e77..a8c134f5 100644
--- a/pesto.c
+++ b/pesto.c
@@ -15,6 +15,7 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <errno.h>
+#include <getopt.h>
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -42,6 +43,32 @@
 		exit(EXIT_FAILURE);					\
 	} while (0)
 
+#define debug(...)							\
+	do {								\
+		if (verbosity > 1) {					\
+			FPRINTF(stderr, __VA_ARGS__);			\
+			FPRINTF(stderr, "\n");				\
+		}							\
+	} while (0)
+
+/**
+ * usage() - Print usage, exit with given status code
+ * @name:	Executable name
+ * @f:		Stream to print usage info to
+ * @status:	Status code for exit(2)
+ */
+static void usage(const char *name, FILE *f, int status)
+{
+	FPRINTF(f, "Usage: %s [OPTION]... PATH\n", name);
+	FPRINTF(f,
+		"\n"
+		"  -v, --verbose		Be more verbose\n"
+		"  -q, --quiet		Be less verbose\n"
+		"  -h, --help		Display this help message and exit\n"
+		"  --version		Show version and exit\n");
+	exit(status);
+}
+
 /**
  * main() - Entry point and whole program with loop
  * @argc:	Argument count
@@ -56,13 +83,20 @@
  */
 int main(int argc, char **argv)
 {
+	const struct option options[] = {
+		{"quiet",	no_argument,		NULL,		'q' },
+		{"verbose",	no_argument,		NULL,		'v' },
+		{"help",	no_argument,		NULL,		'h' },
+		{"version",	no_argument,		NULL,		1 },
+		{ 0 },
+	};
 	struct sockaddr_un a = { AF_UNIX, "" };
+	const char *optstring = "vh";
 	struct pesto_hello hello;
 	struct sock_fprog prog;
+	int optname, ret, s;
 	uint32_t s_version;
-	int ret, s;
-
-	prctl(PR_SET_DUMPABLE, 0);
+	int verbosity = 1;
 
 	prog.len = (unsigned short)sizeof(filter_pesto) /
 				   sizeof(filter_pesto[0]);
@@ -71,15 +105,40 @@ int main(int argc, char **argv)
 	    prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog))
 		die("Failed to apply seccomp filter");
 
-	if (argc < 2)
-		die("Usage: %s CONTROLPATH", argv[0]);
+	do {
+		optname = getopt_long(argc, argv, optstring, options, NULL);
+
+		switch (optname) {
+		case -1:
+		case 0:
+			break;
+		case 'h':
+			usage(argv[0], stdout, EXIT_SUCCESS);
+			break;
+		case 'q':
+			verbosity--;
+			break;
+		case 'v':
+			verbosity++;
+			break;
+		case 1:
+			FPRINTF(stdout, "pesto ");
+			FPRINTF(stdout, VERSION_BLOB);
+			exit(EXIT_SUCCESS);
+		default:
+			usage(argv[0], stderr, EXIT_FAILURE);
+		}
+	} while (optname != -1);
+
+	if (argc - optind != 1)
+		usage(argv[0], stderr, EXIT_FAILURE);
 
 	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
 		die("Failed to create AF_UNIX socket: %s", strerror(errno));
 
-	ret = snprintf(a.sun_path, sizeof(a.sun_path), "%s", argv[1]);
+	ret = snprintf(a.sun_path, sizeof(a.sun_path), "%s", argv[optind]);
 	if (ret <= 0 || ret >= (int)sizeof(a.sun_path))
-		die("Invalid socket path \"%s\"", argv[1]);
+		die("Invalid socket path \"%s\"", argv[optind]);
 
 	ret = connect(s, (struct sockaddr *)&a, sizeof(a));
 	if (ret < 0) {
@@ -87,6 +146,8 @@ int main(int argc, char **argv)
 		    a.sun_path, strerror(errno));
 	}
 
+	debug("Connected to passt/pasta control socket");
+	
 	ret = seread_var(s, &hello);
 	if (ret < 0)
 		die("Couldn't read server greeting: %s", strerror(errno));
@@ -96,6 +157,8 @@ int main(int argc, char **argv)
 
 	s_version = ntohl(hello.version);
 
+	debug("Server protocol version: %"PRIu32, s_version);
+
 	if (s_version > PESTO_PROTOCOL_VERSION) {
 		die("Unknown server protocol version %"PRIu32" > %"PRIu32"\n",
 		    s_version, PESTO_PROTOCOL_VERSION);
diff --git a/util.h b/util.h
index e7993f4d..d7c397f6 100644
--- a/util.h
+++ b/util.h
@@ -21,14 +21,6 @@
 
 #include "log.h"
 
-#define VERSION_BLOB							       \
-	VERSION "\n"							       \
-	"Copyright Red Hat\n"						       \
-	"GNU General Public License, version 2 or later\n"		       \
-	"  <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>\n"	       \
-	"This is free software: you are free to change and redistribute it.\n" \
-	"There is NO WARRANTY, to the extent permitted by law.\n\n"
-
 #ifndef SECCOMP_RET_KILL_PROCESS
 #define SECCOMP_RET_KILL_PROCESS	SECCOMP_RET_KILL
 #endif
-- 
2.53.0