For file backed md(4) devices output their source file via

'mdconfig -l -u <unit>'.
Bump version number, as this change breaks ABI/API.

3 files changed, 22 insertions, 8 deletions

diff --git a/sbin/mdconfig/mdconfig.c b/sbin/mdconfig/mdconfig.c
index 8aa34ac..083779d4 100644
--- a/sbin/mdconfig/mdconfig.c
+++ b/sbin/mdconfig/mdconfig.c
@@ -115,8 +115,11 @@ main(int argc, char **argv)
 				mdio.md_options = MD_CLUSTER | MD_AUTOUNIT | MD_COMPRESS;
 				cmdline = 2;
 			}
-			mdio.md_file = optarg;
-			fd = open(optarg, O_RDONLY);
+			if (realpath(optarg, mdio.md_file) == NULL) {
+				err(1, "could not find full path for %s",
+				    optarg);
+			}
+			fd = open(mdio.md_file, O_RDONLY);
 			if (fd < 0)
 				err(1, "could not open %s", optarg);
 			else if (mdio.md_mediasize == 0) {
@@ -300,6 +303,8 @@ query(const int fd, const int unit)
 	}
 	printf("\t");
 	prthumanval(mdio.md_mediasize);
+	if (mdio.md_type == MD_VNODE)
+		printf("\t%s", mdio.md_file);
 	printf("\n");
 
 	return (0);
diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 22e4a11..29bed2c 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -174,6 +174,7 @@ struct md_s {
 
 	/* MD_VNODE related fields */
 	struct vnode *vnode;
+	char file[PATH_MAX];
 	struct ucred *cred;
 
 	/* MD_SWAP related fields */
@@ -861,15 +862,19 @@ mdcreate_vnode(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
 	struct nameidata nd;
 	int error, flags;
 
+	if (strlcpy(sc->file, mdio->md_file, sizeof(sc->file)) >=
+	    sizeof(sc->file)) {
+		return (ENAMETOOLONG);
+	}
 	flags = FREAD|FWRITE;
-	NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, mdio->md_file, td);
+	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, sc->file, td);
 	error = vn_open(&nd, &flags, 0, -1);
 	if (error) {
 		NDFREE(&nd, NDF_ONLY_PNBUF);
 		if (error != EACCES && error != EPERM && error != EROFS)
 			return (error);
 		flags &= ~FWRITE;
-		NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, mdio->md_file, td);
+		NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, sc->file, td);
 		error = vn_open(&nd, &flags, 0, -1);
 	}
 	NDFREE(&nd, NDF_ONLY_PNBUF);
@@ -1097,11 +1102,15 @@ mdctlioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread
 		mdio->md_mediasize = sc->mediasize;
 		mdio->md_sectorsize = sc->sectorsize;
 		if (sc->type == MD_VNODE) {
-			/* XXX fill this in */
-			mdio->md_file = NULL;
+			if (strlcpy(mdio->md_file, sc->file,
+			    sizeof(mdio->md_file)) >= sizeof(mdio->md_file)) {
+				return (ENAMETOOLONG);
+			}
 		}
 		return (0);
 	case MDIOCLIST:
+		if (mdio->md_version != MDIOVERSION)
+			return (EINVAL);
 		i = 1;
 		LIST_FOREACH(sc, &md_softc_list, list) {
 			if (i == MDNPAD - 1)
diff --git a/sys/sys/mdioctl.h b/sys/sys/mdioctl.h
index e45c096..afc0cb8 100644
--- a/sys/sys/mdioctl.h
+++ b/sys/sys/mdioctl.h
@@ -54,20 +54,20 @@ struct md_ioctl {
 	unsigned	md_version;	/* Structure layout version */
 	unsigned	md_unit;	/* unit number */
 	enum md_types	md_type ;	/* type of disk */
-	char		*md_file;	/* pathname of file to mount */
 	off_t		md_mediasize;	/* size of disk in bytes */
 	unsigned	md_sectorsize;	/* sectorsize */
 	unsigned	md_options;	/* options */
 	u_int64_t	md_base;	/* base address */
 	int		md_fwheads;	/* firmware heads */
 	int		md_fwsectors;	/* firmware sectors */
+	char		md_file[PATH_MAX]; /* pathname of file to mount */
 	int		md_pad[MDNPAD];	/* padding for future ideas */
 };
 
 #define MD_NAME		"md"
 #define MD_MODNAME	"g_md"
 #define MDCTL_NAME	"mdctl"
-#define MDIOVERSION	0
+#define MDIOVERSION	1
 
 /*
  * Before you can use a unit, it must be configured with MDIOCSET.