ifconfig: Add format shortcuts.

MFC after:	1 week
Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D45166

2 files changed, 37 insertions, 19 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index 99a4cf8c9751..72f4883a9e26 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd May 1, 2024
+.Dd May 12, 2024
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -135,7 +135,7 @@ and their associated
 .Ar format
 strings are:
 .Pp
-.Bl -tag -width ether
+.Bl -tag -width default
 .It Cm addr
 Adjust the display of inet and inet6 addresses:
 .Pp
@@ -200,6 +200,16 @@ Integer format, for example:
 .Ql prefixlen 64
 .El
 .El
+.Pp
+In addition, the following shortcuts are accepted:
+.Bl -tag -width default
+.It Cm default
+Resets all formats to their default values.
+.It Cm cidr
+Shortcut notation for
+.Cm inet:cidr,inet6:cidr .
+.El
+.Pp
 .It Fl G Ar groupname
 Exclude members of the specified
 .Ar groupname
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index 2cbe7a881bd0..a8bd5a0c89db 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -313,14 +313,10 @@ cmpifaddrs(struct ifaddrs *a, struct ifaddrs *b, struct ifa_queue *q)
 static void freeformat(void)
 {
 
-	if (f_inet != NULL)
-		free(f_inet);
-	if (f_inet6 != NULL)
-		free(f_inet6);
-	if (f_ether != NULL)
-		free(f_ether);
-	if (f_addr != NULL)
-		free(f_addr);
+	free(f_inet);
+	free(f_inet6);
+	free(f_ether);
+	free(f_addr);
 }
 
 static void setformat(char *input)
@@ -330,9 +326,18 @@ static void setformat(char *input)
 	formatstr = strdup(input);
 	while ((category = strsep(&formatstr, ",")) != NULL) {
 		modifier = strchr(category, ':');
-		if (modifier == NULL || modifier[1] == '\0') {
-			warnx("Skipping invalid format specification: %s\n",
-			    category);
+		if (modifier == NULL) {
+			if (strcmp(category, "default") == 0) {
+				freeformat();
+			} else if (strcmp(category, "cidr") == 0) {
+				free(f_inet);
+				f_inet = strdup(category);
+				free(f_inet6);
+				f_inet6 = strdup(category);
+			} else {
+				warnx("Skipping invalid format: %s\n",
+				    category);
+			}
 			continue;
 		}
 
@@ -340,14 +345,19 @@ static void setformat(char *input)
 		modifier[0] = '\0';
 		modifier++;
 
-		if (strcmp(category, "addr") == 0)
+		if (strcmp(category, "addr") == 0) {
+			free(f_addr);
 			f_addr = strdup(modifier);
-		else if (strcmp(category, "ether") == 0)
+		} else if (strcmp(category, "ether") == 0) {
+			free(f_ether);
 			f_ether = strdup(modifier);
-		else if (strcmp(category, "inet") == 0)
+		} else if (strcmp(category, "inet") == 0) {
+			free(f_inet);
 			f_inet = strdup(modifier);
-		else if (strcmp(category, "inet6") == 0)
+		} else if (strcmp(category, "inet6") == 0) {
+			free(f_inet6);
 			f_inet6 = strdup(modifier);
+		}
 	}
 	free(formatstr);
 }
@@ -612,8 +622,6 @@ main(int ac, char *av[])
 		.io_s = -1,
 	};
 
-	f_inet = f_inet6 = f_ether = f_addr = NULL;
-
 	lifh = ifconfig_open();
 	if (lifh == NULL)
 		err(EXIT_FAILURE, "ifconfig_open");