MFC r310088, r310090, r310095

r310088:
Put the undocumented df feature of mounting filesystems from device
nodes
under an ifdef.  Leave enabled.

Reviewed by:	cem
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D8513

r310090:
Mount filesystems without executable permissions since they should never
be used.

Reviewed by:	cem
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D8513

r310095:
Use nmount(2) rather than the obsolete mount(2).

Reviewed by:	cem
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D8513

2 files changed, 40 insertions, 4 deletions

diff --git a/bin/df/Makefile b/bin/df/Makefile
index df6574c..2dde4cc 100644
--- a/bin/df/Makefile
+++ b/bin/df/Makefile
@@ -9,6 +9,9 @@ SRCS=	df.c vfslist.c
 
 CFLAGS+= -I${MOUNT}
 
+CFLAGS+= -DMOUNT_CHAR_DEVS
+SRCS+=	getmntopts.c
+
 DPADD=	${LIBUTIL}
 LDADD=	-lutil
 
diff --git a/bin/df/df.c b/bin/df/df.c
index ba87055..3c10878 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -50,10 +50,15 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 #include <sys/mount.h>
 #include <sys/sysctl.h>
+#ifdef MOUNT_CHAR_DEVS
 #include <ufs/ufs/ufsmount.h>
+#endif
 #include <err.h>
 #include <libutil.h>
 #include <locale.h>
+#ifdef MOUNT_CHAR_DEVS
+#include <mntopts.h>
+#endif
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -97,7 +102,9 @@ imax(int a, int b)
 
 static int	aflag = 0, cflag, hflag, iflag, kflag, lflag = 0, nflag, Tflag;
 static int	thousands;
+#ifdef MOUNT_CHAR_DEVS
 static struct	ufs_args mdev;
+#endif
 
 int
 main(int argc, char *argv[])
@@ -106,11 +113,21 @@ main(int argc, char *argv[])
 	struct statfs statfsbuf, totalbuf;
 	struct maxwidths maxwidths;
 	struct statfs *mntbuf;
+#ifdef MOUNT_CHAR_DEVS
+	struct iovec *iov = NULL;
+#endif
 	const char *fstype;
-	char *mntpath, *mntpt;
+#ifdef MOUNT_CHAR_DEVS
+	char *mntpath;
+	char errmsg[255] = {0};
+#endif
+	char *mntpt;
 	const char **vfslist;
 	int i, mntsize;
 	int ch, rv;
+#ifdef MOUNT_CHAR_DEVS
+	int iovlen = 0;
+#endif
 
 	fstype = "ufs";
 	(void)setlocale(LC_ALL, "");
@@ -215,6 +232,7 @@ main(int argc, char *argv[])
 				rv = 1;
 				continue;
 			}
+#ifdef MOUNT_CHAR_DEVS
 		} else if (S_ISCHR(stbuf.st_mode)) {
 			if ((mntpt = getmntpt(*argv)) == NULL) {
 				mdev.fspec = *argv;
@@ -231,9 +249,23 @@ main(int argc, char *argv[])
 					free(mntpath);
 					continue;
 				}
-				if (mount(fstype, mntpt, MNT_RDONLY,
-				    &mdev) != 0) {
-					warn("%s", *argv);
+				if (iov != NULL)
+					free_iovec(&iov, &iovlen);
+				build_iovec_argf(&iov, &iovlen, "fstype", "%s",
+				    fstype);
+				build_iovec_argf(&iov, &iovlen, "fspath", "%s",
+				    mntpath);
+				build_iovec_argf(&iov, &iovlen, "from", "%s",
+				    *argv);
+				build_iovec(&iov, &iovlen, "errmsg", errmsg,
+				    sizeof(errmsg));
+				if (nmount(iov, iovlen,
+				    MNT_RDONLY|MNT_NOEXEC) < 0) {
+					if (errmsg[0])
+						warn("%s: %s", *argv,
+						    errmsg);
+					else
+						warn("%s", *argv);
 					rv = 1;
 					(void)rmdir(mntpt);
 					free(mntpath);
@@ -252,6 +284,7 @@ main(int argc, char *argv[])
 				free(mntpath);
 				continue;
 			}
+#endif
 		} else
 			mntpt = *argv;