1 files changed, 164 insertions, 0 deletions
diff --git a/usr/src/lib/libzfsbootenv/common/lzbe_device.c b/usr/src/lib/libzfsbootenv/common/lzbe_device.c
new file mode 100644
index 0000000000..670efd8b06
--- /dev/null
+++ b/usr/src/lib/libzfsbootenv/common/lzbe_device.c
@@ -0,0 +1,164 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+/*
+ * Copyright 2020 Toomas Soome <tsoome@me.com>
+ */
+
+#include <sys/types.h>
+#include <string.h>
+#include <libzfs.h>
+#include <libzfsbootenv.h>
+#include <sys/zfs_bootenv.h>
+#include <sys/vdev_impl.h>
+
+/*
+ * Store device name to zpool label bootenv area.
+ * This call will set bootenv version to VB_NVLIST, if bootenv currently
+ * does contain other version, then old data will be replaced.
+ */
+int
+lzbe_set_boot_device(const char *pool, lzbe_flags_t flag, const char *device)
+{
+	libzfs_handle_t *hdl;
+	zpool_handle_t *zphdl;
+	nvlist_t *nv;
+	char *descriptor;
+	uint64_t version;
+	int rv = -1;
+
+	if (pool == NULL || *pool == '\0')
+		return (rv);
+
+	if ((hdl = libzfs_init()) == NULL)
+		return (rv);
+
+	zphdl = zpool_open(hdl, pool);
+	if (zphdl == NULL) {
+		libzfs_fini(hdl);
+		return (rv);
+	}
+
+	switch (flag) {
+	case lzbe_add:
+		rv = zpool_get_bootenv(zphdl, &nv);
+		if (rv == 0) {
+			/*
+			 * We got the nvlist, check for version.
+			 * if version is missing or is not VB_NVLIST,
+			 * create new list.
+			 */
+			rv = nvlist_lookup_uint64(nv, BOOTENV_VERSION,
+			    &version);
+			if (rv == 0 && version == VB_NVLIST)
+				break;
+
+			/* Drop this nvlist */
+			fnvlist_free(nv);
+		}
+		/* FALLTHROUGH */
+	case lzbe_replace:
+		nv = fnvlist_alloc();
+		break;
+	default:
+		return (rv);
+	}
+
+	/* version is mandatory */
+	fnvlist_add_uint64(nv, BOOTENV_VERSION, VB_NVLIST);
+
+	/*
+	 * If device name is empty, remove boot device configuration.
+	 */
+	if ((device == NULL || *device == '\0')) {
+		if (nvlist_exists(nv, OS_BOOTONCE))
+			fnvlist_remove(nv, OS_BOOTONCE);
+	} else {
+		/*
+		 * Use device name directly if it does start with
+		 * prefix "zfs:". Otherwise, add prefix and sufix.
+		 */
+		if (strncmp(device, "zfs:", 4) == 0) {
+			fnvlist_add_string(nv, OS_BOOTONCE, device);
+		} else {
+			descriptor = NULL;
+			if (asprintf(&descriptor, "zfs:%s:", device) > 0)
+				fnvlist_add_string(nv, OS_BOOTONCE, descriptor);
+			else
+				rv = ENOMEM;
+			free(descriptor);
+		}
+	}
+
+	rv = zpool_set_bootenv(zphdl, nv);
+	if (rv != 0)
+		fprintf(stderr, "%s\n", libzfs_error_description(hdl));
+
+	fnvlist_free(nv);
+	zpool_close(zphdl);
+	libzfs_fini(hdl);
+	return (rv);
+}
+
+/*
+ * Return boot device name from bootenv, if set.
+ */
+int
+lzbe_get_boot_device(const char *pool, char **device)
+{
+	libzfs_handle_t *hdl;
+	zpool_handle_t *zphdl;
+	nvlist_t *nv;
+	char *val;
+	int rv = -1;
+
+	if (pool == NULL || *pool == '\0' || device == NULL)
+		return (rv);
+
+	if ((hdl = libzfs_init()) == NULL)
+		return (rv);
+
+	zphdl = zpool_open(hdl, pool);
+	if (zphdl == NULL) {
+		libzfs_fini(hdl);
+		return (rv);
+	}
+
+	rv = zpool_get_bootenv(zphdl, &nv);
+	if (rv == 0) {
+		rv = nvlist_lookup_string(nv, OS_BOOTONCE, &val);
+		if (rv == 0) {
+			/*
+			 * zfs device descriptor is in form of "zfs:dataset:",
+			 * we only do need dataset name.
+			 */
+			if (strncmp(val, "zfs:", 4) == 0) {
+				val += 4;
+				val = strdup(val);
+				if (val != NULL) {
+					size_t len = strlen(val);
+
+					if (val[len - 1] == ':')
+						val[len - 1] = '\0';
+					*device = val;
+				} else {
+					rv = ENOMEM;
+				}
+			} else {
+				rv = EINVAL;
+			}
+		}
+		nvlist_free(nv);
+	}
+
+	zpool_close(zphdl);
+	libzfs_fini(hdl);
+	return (rv);
+}