zfs label bootenv should store data as nvlist

nvlist does allow us to support different data types and systems.

To encapsulate user data to/from nvlist, the libzfsbootenv library is
provided.

Reviewed-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes #10774

lib/libzfsbootenv/.gitignore

@@ -0,0 +1 @@
+/libzfsbootenv.pc

lib/libzfsbootenv/Makefile.am

@@ -0,0 +1,32 @@
+include $(top_srcdir)/config/Rules.am
+
+pkgconfig_DATA = libzfsbootenv.pc
+
+lib_LTLIBRARIES = libzfsbootenv.la
+
+if BUILD_FREEBSD
+DEFAULT_INCLUDES += -I$(top_srcdir)/include/os/freebsd/zfs
+endif
+if BUILD_LINUX
+DEFAULT_INCLUDES += -I$(top_srcdir)/include/os/linux/zfs
+endif
+
+USER_C = \
+	lzbe_device.c \
+	lzbe_pair.c \
+	lzbe_util.c
+
+dist_libzfsbootenv_la_SOURCES = \
+	$(USER_C)
+
+libzfsbootenv_la_LIBADD = \
+	$(abs_top_builddir)/lib/libzfs/libzfs.la \
+	$(abs_top_builddir)/lib/libnvpair/libnvpair.la
+
+libzfsbootenv_la_LDFLAGS =
+
+if !ASAN_ENABLED
+libzfsbootenv_la_LDFLAGS += -Wl,-z,defs
+endif
+
+libzfsbootenv_la_LDFLAGS += -version-info 1:0:0

lib/libzfsbootenv/libzfsbootenv.pc.in

@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: libzfsbootenv
+Description: LibZFSBootENV library
+Version: @VERSION@
+URL: https://zfsonlinux.org
+Requires: libzfs libnvpair
+Cflags: -I${includedir}
+Libs: -L${libdir} -lzfsbootenv

lib/libzfsbootenv/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);
+}

lib/libzfsbootenv/lzbe_pair.c

@@ -0,0 +1,329 @@
+/*
+ * 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>
+
+/*
+ * Get or create nvlist. If key is not NULL, get nvlist from bootenv,
+ * otherwise return bootenv.
+ */
+int
+lzbe_nvlist_get(const char *pool, const char *key, void **ptr)
+{
+	libzfs_handle_t *hdl;
+	zpool_handle_t *zphdl;
+	nvlist_t *nv;
+	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);
+	}
+
+	rv = zpool_get_bootenv(zphdl, &nv);
+	if (rv == 0) {
+		nvlist_t *nvl, *dup;
+
+		if (key != NULL) {
+			rv = nvlist_lookup_nvlist(nv, key, &nvl);
+			if (rv == 0) {
+				rv = nvlist_dup(nvl, &dup, 0);
+				nvlist_free(nv);
+				if (rv == 0)
+					nv = dup;
+				else
+					nv = NULL;
+			} else {
+				nvlist_free(nv);
+				rv = nvlist_alloc(&nv, NV_UNIQUE_NAME, 0);
+			}
+		}
+		*ptr = nv;
+	}
+
+	zpool_close(zphdl);
+	libzfs_fini(hdl);
+	return (rv);
+}
+
+int
+lzbe_nvlist_set(const char *pool, const char *key, void *ptr)
+{
+	libzfs_handle_t *hdl;
+	zpool_handle_t *zphdl;
+	nvlist_t *nv;
+	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);
+	}
+
+	if (key != NULL) {
+		rv = zpool_get_bootenv(zphdl, &nv);
+		if (rv == 0) {
+			rv = nvlist_add_nvlist(nv, key, ptr);
+			if (rv == 0)
+				rv = zpool_set_bootenv(zphdl, nv);
+			nvlist_free(nv);
+		}
+	} else {
+		rv = zpool_set_bootenv(zphdl, ptr);
+	}
+
+	zpool_close(zphdl);
+	libzfs_fini(hdl);
+	return (rv);
+}
+
+/*
+ * free nvlist we got via lzbe_nvlist_get()
+ */
+void
+lzbe_nvlist_free(void *ptr)
+{
+	nvlist_free(ptr);
+}
+
+static const char *typenames[] = {
+	"DATA_TYPE_UNKNOWN",
+	"DATA_TYPE_BOOLEAN",
+	"DATA_TYPE_BYTE",
+	"DATA_TYPE_INT16",
+	"DATA_TYPE_UINT16",
+	"DATA_TYPE_INT32",
+	"DATA_TYPE_UINT32",
+	"DATA_TYPE_INT64",
+	"DATA_TYPE_UINT64",
+	"DATA_TYPE_STRING",
+	"DATA_TYPE_BYTE_ARRAY",
+	"DATA_TYPE_INT16_ARRAY",
+	"DATA_TYPE_UINT16_ARRAY",
+	"DATA_TYPE_INT32_ARRAY",
+	"DATA_TYPE_UINT32_ARRAY",
+	"DATA_TYPE_INT64_ARRAY",
+	"DATA_TYPE_UINT64_ARRAY",
+	"DATA_TYPE_STRING_ARRAY",
+	"DATA_TYPE_HRTIME",
+	"DATA_TYPE_NVLIST",
+	"DATA_TYPE_NVLIST_ARRAY",
+	"DATA_TYPE_BOOLEAN_VALUE",
+	"DATA_TYPE_INT8",
+	"DATA_TYPE_UINT8",
+	"DATA_TYPE_BOOLEAN_ARRAY",
+	"DATA_TYPE_INT8_ARRAY",
+	"DATA_TYPE_UINT8_ARRAY"
+};
+
+static int
+nvpair_type_from_name(const char *name)
+{
+	unsigned i;
+
+	for (i = 0; i < ARRAY_SIZE(typenames); i++) {
+		if (strcmp(name, typenames[i]) == 0)
+			return (i);
+	}
+	return (0);
+}
+
+/*
+ * Add pair defined by key, type and value into nvlist.
+ */
+int
+lzbe_add_pair(void *ptr, const char *key, const char *type, void *value,
+    size_t size)
+{
+	nvlist_t *nv = ptr;
+	data_type_t dt;
+	int rv = 0;
+
+	if (ptr == NULL || key == NULL || value == NULL)
+		return (rv);
+
+	if (type == NULL)
+		type = "DATA_TYPE_STRING";
+	dt = nvpair_type_from_name(type);
+	if (dt == DATA_TYPE_UNKNOWN)
+		return (EINVAL);
+
+	switch (dt) {
+	case DATA_TYPE_BYTE:
+		if (size != sizeof (uint8_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_byte(nv, key, *(uint8_t *)value);
+		break;
+
+	case DATA_TYPE_INT16:
+		if (size != sizeof (int16_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_int16(nv, key, *(int16_t *)value);
+		break;
+
+	case DATA_TYPE_UINT16:
+		if (size != sizeof (uint16_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_uint16(nv, key, *(uint16_t *)value);
+		break;
+
+	case DATA_TYPE_INT32:
+		if (size != sizeof (int32_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_int32(nv, key, *(int32_t *)value);
+		break;
+
+	case DATA_TYPE_UINT32:
+		if (size != sizeof (uint32_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_uint32(nv, key, *(uint32_t *)value);
+		break;
+
+	case DATA_TYPE_INT64:
+		if (size != sizeof (int64_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_int64(nv, key, *(int64_t *)value);
+		break;
+
+	case DATA_TYPE_UINT64:
+		if (size != sizeof (uint64_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_uint64(nv, key, *(uint64_t *)value);
+		break;
+
+	case DATA_TYPE_STRING:
+		rv = nvlist_add_string(nv, key, value);
+		break;
+
+	case DATA_TYPE_BYTE_ARRAY:
+		rv = nvlist_add_byte_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_INT16_ARRAY:
+		rv = nvlist_add_int16_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_UINT16_ARRAY:
+		rv = nvlist_add_uint16_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_INT32_ARRAY:
+		rv = nvlist_add_int32_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_UINT32_ARRAY:
+		rv = nvlist_add_uint32_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_INT64_ARRAY:
+		rv = nvlist_add_int64_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_UINT64_ARRAY:
+		rv = nvlist_add_uint64_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_STRING_ARRAY:
+		rv = nvlist_add_string_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_NVLIST:
+		rv = nvlist_add_nvlist(nv, key, (nvlist_t *)value);
+		break;
+
+	case DATA_TYPE_NVLIST_ARRAY:
+		rv = nvlist_add_nvlist_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_BOOLEAN_VALUE:
+		if (size != sizeof (boolean_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_boolean_value(nv, key, *(boolean_t *)value);
+		break;
+
+	case DATA_TYPE_INT8:
+		if (size != sizeof (int8_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_int8(nv, key, *(int8_t *)value);
+		break;
+
+	case DATA_TYPE_UINT8:
+		if (size != sizeof (uint8_t)) {
+			rv = EINVAL;
+			break;
+		}
+		rv = nvlist_add_uint8(nv, key, *(uint8_t *)value);
+		break;
+
+	case DATA_TYPE_BOOLEAN_ARRAY:
+		rv = nvlist_add_boolean_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_INT8_ARRAY:
+		rv = nvlist_add_int8_array(nv, key, value, size);
+		break;
+
+	case DATA_TYPE_UINT8_ARRAY:
+		rv = nvlist_add_uint8_array(nv, key, value, size);
+		break;
+
+	default:
+		return (ENOTSUP);
+	}
+
+	return (rv);
+}
+
+int
+lzbe_remove_pair(void *ptr, const char *key)
+{
+
+	return (nvlist_remove_all(ptr, key));
+}

lib/libzfsbootenv/lzbe_util.c

@@ -0,0 +1,39 @@
+/*
+ * 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>
+
+/*
+ * Output bootenv information.
+ */
+int
+lzbe_bootenv_print(const char *pool, const char *nvlist, FILE *of)
+{
+	nvlist_t *nv;
+	int rv = -1;
+
+	if (pool == NULL || *pool == '\0' || of == NULL)
+		return (rv);
+
+	rv = lzbe_nvlist_get(pool, nvlist, (void **)&nv);
+	if (rv == 0) {
+		nvlist_print(of, nv);
+		nvlist_free(nv);
+	}
+
+	return (rv);
+}