MFC r295836:

ifconfig(8): can't use 'name' or 'description' when creating interface with auto numbering

If one does 'ifconfig tap create name blah', it will return error because the
'name' command doesn't properly populate the request sent to ioctl(...). The
'description' command has the same bug, and is also fixed with this patch.

If one does 'ifconfig tap create mtu 9000 name blah', it DOES work, but 'tap0'
(or other sequence number) is echoed, instead of the expected 'blah'. (assuming
the name change actually succeeded)

PR:		    206876
Submitted by:       Marie Helene Kvello-Aune <marieheleneka@gmail.com>
Differential Revision:      https://reviews.freebsd.org/D5341

3 files changed, 24 insertions, 2 deletions

diff --git a/sbin/ifconfig/ifclone.c b/sbin/ifconfig/ifclone.c
index 6a60d41..0eda438 100644
--- a/sbin/ifconfig/ifclone.c
+++ b/sbin/ifconfig/ifclone.c
@@ -144,11 +144,12 @@ ifclonecreate(int s, void *arg)
 	}
 
 	/*
-	 * If we get a different name back than we put in, print it.
+	 * If we get a different name back than we put in, update record and
+	 * indicate it should be printed later.
 	 */
 	if (strncmp(name, ifr.ifr_name, sizeof(name)) != 0) {
 		strlcpy(name, ifr.ifr_name, sizeof(name));
-		printf("%s\n", name);
+		printifname = 1;
 	}
 }
 
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index 19bd1ac..47b75c3 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -93,6 +93,7 @@ int	clearaddr;
 int	newaddr = 1;
 int	verbose;
 int	noload;
+int	printifname = 0;
 
 int	supmedia = 0;
 int	printkeys = 0;		/* Print keying material for interfaces. */
@@ -108,6 +109,8 @@ static struct afswtch *af_getbyname(const char *name);
 static struct afswtch *af_getbyfamily(int af);
 static void af_other_status(int);
 
+void printifnamemaybe(void);
+
 static struct option *opts = NULL;
 
 void
@@ -141,6 +144,12 @@ usage(void)
 	exit(1);
 }
 
+void printifnamemaybe()
+{
+	if (printifname)
+		printf("%s\n", name);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -156,6 +165,12 @@ main(int argc, char *argv[])
 	size_t iflen;
 
 	all = downonly = uponly = namesonly = noload = verbose = 0;
+	
+	/*
+	 * Ensure we print interface name when expected to,
+	 * even if we terminate early due to error.
+	 */
+	atexit(printifnamemaybe);
 
 	/* Parse leading line options */
 	strlcpy(options, "adklmnuv", sizeof(options));
@@ -856,6 +871,8 @@ setifname(const char *val, int dummy __unused, int s,
     const struct afswtch *afp)
 {
 	char *newname;
+	
+	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
 
 	newname = strdup(val);
 	if (newname == NULL)
@@ -865,6 +882,7 @@ setifname(const char *val, int dummy __unused, int s,
 		free(newname);
 		err(1, "ioctl SIOCSIFNAME (set name)");
 	}
+	printifname = 1;
 	strlcpy(name, newname, sizeof(name));
 	free(newname);
 }
@@ -876,6 +894,8 @@ setifdescr(const char *val, int dummy __unused, int s,
 {
 	char *newdescr;
 
+	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
+	
 	ifr.ifr_buffer.length = strlen(val) + 1;
 	if (ifr.ifr_buffer.length == 1) {
 		ifr.ifr_buffer.buffer = newdescr = NULL;
diff --git a/sbin/ifconfig/ifconfig.h b/sbin/ifconfig/ifconfig.h
index 6df9acf..ada224f 100644
--- a/sbin/ifconfig/ifconfig.h
+++ b/sbin/ifconfig/ifconfig.h
@@ -133,6 +133,7 @@ extern	int supmedia;
 extern	int printkeys;
 extern	int newaddr;
 extern	int verbose;
+extern	int printifname;
 
 void	setifcap(const char *, int value, int s, const struct afswtch *);