copystr(9): Move to deprecate (attempt #2)

This reapplies logical r360944 and r360946 (reverting r360955), with fixed
copystr() stand-in replacement macro.  Eventually the goal is to convert
consumers and kill the macro, but for a first step it helps if the macro is
correct.

Prior commit message:

Unlike the other copy*() functions, it does not serve to copy from one
address space to another or protect against potential faults.  It's just
an older incarnation of the now-more-common strlcpy().

Add a coccinelle script to tools/ which can be used to mechanically
convert existing instances where replacement with strlcpy is trivial.
In the two cases which matched, fuse_vfsops.c and union_vfsops.c, the
code was further refactored manually to simplify.

Replace the declaration of copystr() in systm.h with a small macro
wrapper around strlcpy (with correction from brooks@ -- thanks).

Remove N redundant MI implementations of copystr.  For MIPS, this
entailed inlining the assembler copystr into the only consumer,
copyinstr, and making the latter a leaf function.

Reviewed by:		jhb (earlier version)
Discussed with:		brooks (thanks!)
Differential Revision:	https://reviews.freebsd.org/D24672

2 files changed, 4 insertions, 11 deletions

diff --git a/sys/fs/fuse/fuse_vfsops.c b/sys/fs/fuse/fuse_vfsops.c
index 484a0da216e2..93e2b922b765 100644
--- a/sys/fs/fuse/fuse_vfsops.c
+++ b/sys/fs/fuse/fuse_vfsops.c
@@ -303,8 +303,6 @@ fuse_vfsop_mount(struct mount *mp)
 	int daemon_timeout;
 	int fd;
 
-	size_t len;
-
 	struct cdev *fdev;
 	struct fuse_data *data = NULL;
 	struct thread *td;
@@ -437,8 +435,8 @@ fuse_vfsop_mount(struct mount *mp)
 		strlcat(mp->mnt_stat.f_fstypename, ".", MFSNAMELEN);
 		strlcat(mp->mnt_stat.f_fstypename, subtype, MFSNAMELEN);
 	}
-	copystr(fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &len);
-	bzero(mp->mnt_stat.f_mntfromname + len, MNAMELEN - len);
+	memset(mp->mnt_stat.f_mntfromname, 0, MNAMELEN);
+	strlcpy(mp->mnt_stat.f_mntfromname, fspec, MNAMELEN);
 	mp->mnt_iosize_max = MAXPHYS;
 
 	/* Now handshaking with daemon */
diff --git a/sys/fs/unionfs/union_vfsops.c b/sys/fs/unionfs/union_vfsops.c
index d002fb5ef98a..b65696e34c8e 100644
--- a/sys/fs/unionfs/union_vfsops.c
+++ b/sys/fs/unionfs/union_vfsops.c
@@ -83,7 +83,6 @@ unionfs_domount(struct mount *mp)
 	char           *tmp;
 	char           *ep;
 	int		len;
-	size_t		done;
 	int		below;
 	uid_t		uid;
 	gid_t		gid;
@@ -304,12 +303,8 @@ unionfs_domount(struct mount *mp)
 	 */
 	vfs_getnewfsid(mp);
 
-	len = MNAMELEN - 1;
-	tmp = mp->mnt_stat.f_mntfromname;
-	copystr((below ? "<below>:" : "<above>:"), tmp, len, &done);
-	len -= done - 1;
-	tmp += done - 1;
-	copystr(target, tmp, len, NULL);
+	snprintf(mp->mnt_stat.f_mntfromname, MNAMELEN, "<%s>:%s",
+	    below ? "below" : "above", target);
 
 	UNIONFSDEBUG("unionfs_mount: from %s, on %s\n",
 	    mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);