Make the autofs(5) -hosts map more robust, primarily to make it correctly

handle NFS shares containing whitespace. This also adds the -E parameter
to showmount(8).

Reviewed by:	emaste@, jhibbits@, wblock@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5649

3 files changed, 39 insertions, 8 deletions

diff --git a/etc/autofs/special_hosts b/etc/autofs/special_hosts
index f81449d..c498546 100644
--- a/etc/autofs/special_hosts
+++ b/etc/autofs/special_hosts
@@ -10,8 +10,8 @@ if [ $# -eq 0 ]; then
 	exit 0
 fi
 
-out=`showmount -e "$1"`
+out=`showmount -E "$1"`
 [ $? -eq 0 ] || exit 1
 echo "$out" | awk -v host="$1" \
-    'NR > 1 { printf "%s\t%s:%s ", $1, host, $1 } END { printf "\n" }'
+    '{ printf "\"%s\"\t\"%s:%s\" ", $0, host, $0 } END { printf "\n" }'
 
diff --git a/usr.bin/showmount/showmount.8 b/usr.bin/showmount/showmount.8
index 2831593..692c6d6 100644
--- a/usr.bin/showmount/showmount.8
+++ b/usr.bin/showmount/showmount.8
@@ -31,7 +31,7 @@
 .\"     @(#)showmount.8	8.3 (Berkeley) 3/29/95
 .\" $FreeBSD$
 .\"
-.Dd August 16, 2014
+.Dd March 20, 2016
 .Dt SHOWMOUNT 8
 .Os
 .Sh NAME
@@ -40,6 +40,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl a | d
+.Op Fl E
 .Op Fl e
 .Op Fl 1
 .Op Fl 3
@@ -73,6 +74,12 @@ List all mount points in the form:
 .Ed
 .It Fl d
 List directory paths of mount points instead of hosts.
+.It Fl E
+Show the
+.Ar host Ns 's
+exports list in a script-friendly format.
+Client addresses and the header are not shown, and special
+characters are escaped.
 .It Fl e
 Show the
 .Ar host Ns 's
diff --git a/usr.bin/showmount/showmount.c b/usr.bin/showmount/showmount.c
index d0da570..46e58e4 100644
--- a/usr.bin/showmount/showmount.c
+++ b/usr.bin/showmount/showmount.c
@@ -61,13 +61,15 @@ static const char rcsid[] =
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <vis.h>
 
 /* Constant defs */
 #define	ALL	1
 #define	DIRS	2
 
-#define	DODUMP		0x1
-#define	DOEXPORTS	0x2
+#define	DODUMP			0x1
+#define	DOEXPORTS		0x2
+#define	DOPARSABLEEXPORTS	0x4
 
 struct mountlist {
 	struct mountlist *ml_left;
@@ -108,13 +110,14 @@ int tcp_callrpc(const char *host, int prognum, int versnum, int procnum,
 int
 main(int argc, char **argv)
 {
+	char strvised[MNTPATHLEN * 4 + 1];
 	register struct exportslist *exp;
 	register struct grouplist *grp;
 	register int rpcs = 0, mntvers = 3;
 	const char *host;
-	int ch, estat;
+	int ch, estat, nbytes;
 
-	while ((ch = getopt(argc, argv, "ade13")) != -1)
+	while ((ch = getopt(argc, argv, "adEe13")) != -1)
 		switch (ch) {
 		case 'a':
 			if (type == 0) {
@@ -130,6 +133,9 @@ main(int argc, char **argv)
 			} else
 				usage();
 			break;
+		case 'E':
+			rpcs |= DOPARSABLEEXPORTS;
+			break;
 		case 'e':
 			rpcs |= DOEXPORTS;
 			break;
@@ -146,6 +152,13 @@ main(int argc, char **argv)
 	argc -= optind;
 	argv += optind;
 
+	if ((rpcs & DOPARSABLEEXPORTS) != 0) {
+		if ((rpcs & DOEXPORTS) != 0)
+			errx(1, "-E cannot be used with -e");
+		if ((rpcs & DODUMP) != 0)
+			errx(1, "-E cannot be used with -a or -d");
+	}
+
 	if (argc > 0)
 		host = *argv;
 	else
@@ -161,7 +174,7 @@ main(int argc, char **argv)
 			clnt_perrno(estat);
 			errx(1, "can't do mountdump rpc");
 		}
-	if (rpcs & DOEXPORTS)
+	if (rpcs & (DOEXPORTS | DOPARSABLEEXPORTS))
 		if ((estat = tcp_callrpc(host, MOUNTPROG, mntvers,
 			MOUNTPROC_EXPORT, (xdrproc_t)xdr_void, (char *)0,
 			(xdrproc_t)xdr_exportslist, (char *)&exportslist)) != 0) {
@@ -202,6 +215,17 @@ main(int argc, char **argv)
 			exp = exp->ex_next;
 		}
 	}
+	if (rpcs & DOPARSABLEEXPORTS) {
+		exp = exportslist;
+		while (exp) {
+			nbytes = strsnvis(strvised, sizeof(strvised),
+			    exp->ex_dirp, VIS_GLOB | VIS_NL, "\"'$");
+			if (nbytes == -1)
+				err(1, "strsnvis");
+			printf("%s\n", strvised);
+			exp = exp->ex_next;
+		}
+	}
 	exit(0);
 }