freebsd: add ifdefs around legacy ioctl support

Require that ZFS_LEGACY_SUPPORT be defined for legacy ioctl support to
be built.  For now, define it in zfs_ioctl_compat.h so support is always
built.  This will allow systems that need never support pre-openzfs
tools a mechanism to remove support at build time.  This code should
be removed once the need for tool compatability is gone.

No functional change at this time.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brooks Davis <brooks.davis@sri.com>
Closes #14127

include/os/freebsd/zfs/sys/zfs_ioctl_compat.h

@@ -37,6 +37,15 @@
 #include <sys/nvpair.h>
 #endif  /* _KERNEL */
 
+/*
+ * Legacy ioctl support allows compatibility with pre-OpenZFS tools on
+ * FreeBSD.  The need for it will eventually pass (perhaps after FreeBSD
+ * 12 is well out of support), at which point this code can be removed.
+ * For now, downstream consumers may choose to disable this code by
+ * removing the following define.
+ */
+#define	ZFS_LEGACY_SUPPORT
+
 #ifdef	__cplusplus
 extern "C" {
 #endif
@@ -82,6 +91,7 @@ typedef struct zfs_iocparm {
 } zfs_iocparm_t;
 
 
+#ifdef ZFS_LEGACY_SUPPORT
 #define	LEGACY_MAXPATHLEN 1024
 #define	LEGACY_MAXNAMELEN 256
 
@@ -135,6 +145,7 @@ typedef struct zfs_cmd_legacy {
 	uint64_t	zc_createtxg;
 	zfs_stat_t	zc_stat;
 } zfs_cmd_legacy_t;
+#endif
 
 
 #ifdef _KERNEL
@@ -145,10 +156,12 @@ nvlist_t *zfs_ioctl_compat_innvl(zfs_cmd_t *, nvlist_t *, const int,
 nvlist_t *zfs_ioctl_compat_outnvl(zfs_cmd_t *, nvlist_t *, const int,
     const int);
 #endif	/* _KERNEL */
+#ifdef ZFS_LEGACY_SUPPORT
 int zfs_ioctl_legacy_to_ozfs(int request);
 int zfs_ioctl_ozfs_to_legacy(int request);
 void zfs_cmd_legacy_to_ozfs(zfs_cmd_legacy_t *src, zfs_cmd_t *dst);
 void zfs_cmd_ozfs_to_legacy(zfs_cmd_t *src, zfs_cmd_legacy_t *dst);
+#endif
 
 void zfs_cmd_compat_put(zfs_cmd_t *, caddr_t, const int, const int);
 

lib/libzfs_core/os/freebsd/libzfs_core_ioctl.c

@@ -46,8 +46,11 @@ get_zfs_ioctl_version(void)
 static int
 zcmd_ioctl_compat(int fd, int request, zfs_cmd_t *zc, const int cflag)
 {
-	int newrequest, ret;
+	int ret;
+#ifdef ZFS_LEGACY_SUPPORT
+	int newrequest;
 	void *zc_c = NULL;
+#endif
 	unsigned long ncmd;
 	zfs_iocparm_t zp;
 
@@ -58,6 +61,7 @@ zcmd_ioctl_compat(int fd, int request, zfs_cmd_t *zc, const int cflag)
 		zp.zfs_cmd_size = sizeof (zfs_cmd_t);
 		zp.zfs_ioctl_version = ZFS_IOCVER_OZFS;
 		break;
+#ifdef ZFS_LEGACY_SUPPORT
 	case ZFS_CMD_COMPAT_LEGACY:
 		newrequest = zfs_ioctl_ozfs_to_legacy(request);
 		ncmd = _IOWR('Z', newrequest, zfs_iocparm_t);
@@ -67,6 +71,7 @@ zcmd_ioctl_compat(int fd, int request, zfs_cmd_t *zc, const int cflag)
 		zp.zfs_cmd_size = sizeof (zfs_cmd_legacy_t);
 		zp.zfs_ioctl_version = ZFS_IOCVER_LEGACY;
 		break;
+#endif
 	default:
 		abort();
 		return (EINVAL);
@@ -74,14 +79,18 @@ zcmd_ioctl_compat(int fd, int request, zfs_cmd_t *zc, const int cflag)
 
 	ret = ioctl(fd, ncmd, &zp);
 	if (ret) {
+#ifdef ZFS_LEGACY_SUPPORT
 		if (zc_c)
 			free(zc_c);
+#endif
 		return (ret);
 	}
+#ifdef ZFS_LEGACY_SUPPORT
 	if (zc_c) {
 		zfs_cmd_legacy_to_ozfs(zc_c, zc);
 		free(zc_c);
 	}
+#endif
 	return (ret);
 }
 
@@ -100,9 +109,11 @@ lzc_ioctl_fd(int fd, unsigned long request, zfs_cmd_t *zc)
 		zfs_ioctl_version = get_zfs_ioctl_version();
 
 	switch (zfs_ioctl_version) {
+#ifdef ZFS_LEGACY_SUPPORT
 		case ZFS_IOCVER_LEGACY:
 			cflag = ZFS_CMD_COMPAT_LEGACY;
 			break;
+#endif
 		case ZFS_IOCVER_OZFS:
 			cflag = ZFS_CMD_COMPAT_NONE;
 			break;

lib/libzpool/util.c

@@ -261,7 +261,9 @@ pool_active(void *unused, const char *name, uint64_t guid, boolean_t *isactive)
 	(void) unused, (void) guid;
 	zfs_iocparm_t zp;
 	zfs_cmd_t *zc = NULL;
+#ifdef ZFS_LEGACY_SUPPORT
 	zfs_cmd_legacy_t *zcl = NULL;
+#endif
 	unsigned long request;
 	int ret;
 
@@ -296,6 +298,7 @@ pool_active(void *unused, const char *name, uint64_t guid, boolean_t *isactive)
 		umem_free(zc, sizeof (zfs_cmd_t));
 
 		break;
+#ifdef ZFS_LEGACY_SUPPORT
 	case ZFS_IOCVER_LEGACY:
 		zcl = umem_zalloc(sizeof (zfs_cmd_legacy_t), UMEM_NOFAIL);
 
@@ -311,6 +314,7 @@ pool_active(void *unused, const char *name, uint64_t guid, boolean_t *isactive)
 		umem_free(zcl, sizeof (zfs_cmd_legacy_t));
 
 		break;
+#endif
 	default:
 		fprintf(stderr, "unrecognized zfs ioctl version %d", ver);
 		exit(1);

module/os/freebsd/zfs/kmod_core.c

@@ -124,7 +124,9 @@ zfsdev_ioctl(struct cdev *dev, ulong_t zcmd, caddr_t arg, int flag,
 	int vecnum;
 	zfs_iocparm_t *zp;
 	zfs_cmd_t *zc;
+#ifdef ZFS_LEGACY_SUPPORT
 	zfs_cmd_legacy_t *zcl;
+#endif
 	int rc, error;
 	void *uaddr;
 
@@ -133,7 +135,9 @@ zfsdev_ioctl(struct cdev *dev, ulong_t zcmd, caddr_t arg, int flag,
 	zp = (void *)arg;
 	uaddr = (void *)zp->zfs_cmd;
 	error = 0;
+#ifdef ZFS_LEGACY_SUPPORT
 	zcl = NULL;
+#endif
 
 	if (len != sizeof (zfs_iocparm_t)) {
 		printf("len %d vecnum: %d sizeof (zfs_cmd_t) %ju\n",
@@ -142,6 +146,7 @@ zfsdev_ioctl(struct cdev *dev, ulong_t zcmd, caddr_t arg, int flag,
 	}
 
 	zc = kmem_zalloc(sizeof (zfs_cmd_t), KM_SLEEP);
+#ifdef ZFS_LEGACY_SUPPORT
 	/*
 	 * Remap ioctl code for legacy user binaries
 	 */
@@ -157,22 +162,29 @@ zfsdev_ioctl(struct cdev *dev, ulong_t zcmd, caddr_t arg, int flag,
 			goto out;
 		}
 		zfs_cmd_legacy_to_ozfs(zcl, zc);
-	} else if (copyin(uaddr, zc, sizeof (zfs_cmd_t))) {
+	} else
+#endif
+	if (copyin(uaddr, zc, sizeof (zfs_cmd_t))) {
 		error = SET_ERROR(EFAULT);
 		goto out;
 	}
 	error = zfsdev_ioctl_common(vecnum, zc, 0);
+#ifdef ZFS_LEGACY_SUPPORT
 	if (zcl) {
 		zfs_cmd_ozfs_to_legacy(zc, zcl);
 		rc = copyout(zcl, uaddr, sizeof (*zcl));
-	} else {
+	} else
+#endif
+	{
 		rc = copyout(zc, uaddr, sizeof (*zc));
 	}
 	if (error == 0 && rc != 0)
 		error = SET_ERROR(EFAULT);
 out:
+#ifdef ZFS_LEGACY_SUPPORT
 	if (zcl)
 		kmem_free(zcl, sizeof (zfs_cmd_legacy_t));
+#endif
 	kmem_free(zc, sizeof (zfs_cmd_t));
 	MPASS(tsd_get(rrw_tsd_key) == NULL);
 	return (error);

module/os/freebsd/zfs/zfs_ioctl_compat.c

@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/cmn_err.h>
 #include <sys/zfs_ioctl_compat.h>
 
+#ifdef ZFS_LEGACY_SUPPORT
 enum zfs_ioc_legacy {
 	ZFS_IOC_LEGACY_NONE =	-1,
 	ZFS_IOC_LEGACY_FIRST =	0,
@@ -361,3 +362,4 @@ zfs_cmd_ozfs_to_legacy(zfs_cmd_t *src, zfs_cmd_legacy_t *dst)
 	    sizeof (zfs_cmd_t) - 8 - offsetof(zfs_cmd_t, zc_sendobj));
 	dst->zc_jailid = src->zc_zoneid;
 }
+#endif /* ZFS_LEGACY_SUPPORT */