mount_nfs: Only create a mounttab file entry is nmount(2) succeeds

mount_nfs creates entries in the mounttab file and umount removes
them.  Entries in the mounttab file ae used by rpc.umntall to
notify the NFS server that NFSv3 entries need to be removed when
they have not been removed by umount.

Without this patch, an enty will be created in the mounttab file,
even if the nmount(2) syscall fails for the mount.  This patch
modifies the code so that the mounttab entry is only created
after nmount(2) succeeds.

This change only affects NFSv3 and only affects how showmount
displays NFSv3 mounts.

MFC after:	2 weeks

1 files changed, 12 insertions, 8 deletions

diff --git a/sbin/mount_nfs/mount_nfs.c b/sbin/mount_nfs/mount_nfs.c
index 898a6dc9d724..6ea861193df8 100644
--- a/sbin/mount_nfs/mount_nfs.c
+++ b/sbin/mount_nfs/mount_nfs.c
@@ -139,7 +139,7 @@ enum tryret {
 
 static int	sec_name_to_num(const char *sec);
 static const char	*sec_num_to_name(int num);
-static int	getnfsargs(char *, struct iovec **iov, int *iovlen);
+static int	getnfsargs(char **, char **, struct iovec **iov, int *iovlen);
 /* void	set_rpc_maxgrouplist(int); */
 static struct netconfig *getnetconf_cached(const char *netid);
 static const char	*netidbytype(int af, int sotype);
@@ -156,7 +156,7 @@ main(int argc, char *argv[])
 	int c;
 	struct iovec *iov;
 	int num, iovlen;
-	char *mntname, *p, *spec, *tmp;
+	char *host, *mntname, *p, *spec, *tmp;
 	char mntpath[MAXPATHLEN], errmsg[255];
 	char hostname[MAXHOSTNAMELEN + 1], gssn[MAXHOSTNAMELEN + 50];
 	const char *gssname, *nmount_errstr;
@@ -461,7 +461,7 @@ main(int argc, char *argv[])
 		    __DECONST(void *, gssname), strlen(gssname) + 1);
 	}
 
-	if (!getnfsargs(spec, &iov, &iovlen))
+	if (!getnfsargs(&spec, &host, &iov, &iovlen))
 		exit(1);
 
 	/* resolve the mountpoint with realpath(3) */
@@ -479,6 +479,9 @@ main(int argc, char *argv[])
 		else
 			err(1, "nmount: %s%s%s", mntpath, errmsg[0] ? ", " : "",
 			    errmsg);
+	} else if (mountmode != V4 && !add_mtab(host, spec)) {
+		/* Add mounted file system to PATH_MOUNTTAB */
+		warnx("can't update %s for %s:%s", PATH_MOUNTTAB, host, spec);
 	}
 
 	exit(0);
@@ -568,15 +571,16 @@ rtm_ifinfo_sleep(time_t sec)
 }
 
 static int
-getnfsargs(char *spec, struct iovec **iov, int *iovlen)
+getnfsargs(char **specp, char **hostpp, struct iovec **iov, int *iovlen)
 {
 	struct addrinfo hints, *ai_nfs, *ai;
 	enum tryret ret;
 	int ecode, speclen, remoteerr, offset, have_bracket = 0;
-	char *hostp, *delimp, *errstr;
+	char *hostp, *delimp, *errstr, *spec;
 	size_t len;
 	static char nam[MNAMELEN + 1], pname[MAXHOSTNAMELEN + 5];
 
+	spec = *specp;
 	if (*spec == '[' && (delimp = strchr(spec + 1, ']')) != NULL &&
 	    *(delimp + 1) == ':') {
 		hostp = spec + 1;
@@ -718,9 +722,9 @@ getnfsargs(char *spec, struct iovec **iov, int *iovlen)
 	freeaddrinfo(ai_nfs);
 
 	build_iovec(iov, iovlen, "hostname", nam, (size_t)-1);
-	/* Add mounted file system to PATH_MOUNTTAB */
-	if (mountmode != V4 && !add_mtab(hostp, spec))
-		warnx("can't update %s for %s:%s", PATH_MOUNTTAB, hostp, spec);
+
+	*specp = spec;
+	*hostpp = hostp;
 	return (1);
 }