libzdb: Initial breakout of libzdb

Step 1 in trying to slowly rip the zdb functions out of zdb.c
to allow people to play with more flexible things to leverage
zdb's functionality.

No promises on any functions or structs being stable, now or probably
in general unless someone builds a more polished abstraction, the
goal at the moment is to slowly untangle the global state usage
in zdb...

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #15804

lib/libzdb/Makefile.am

@@ -0,0 +1,7 @@
+libzdb_la_CFLAGS = $(AM_CFLAGS) $(LIBRARY_CFLAGS)
+libzdb_la_CFLAGS += -fvisibility=hidden
+
+noinst_LTLIBRARIES += libzdb.la
+
+libzdb_la_SOURCES = \
+	%D%/libzdb.c

lib/libzdb/libzdb.c

@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <getopt.h>
+#include <openssl/evp.h>
+#include <sys/zfs_context.h>
+#include <sys/spa.h>
+#include <sys/spa_impl.h>
+#include <sys/dmu.h>
+#include <sys/zap.h>
+#include <sys/fs/zfs.h>
+#include <sys/zfs_znode.h>
+#include <sys/zfs_sa.h>
+#include <sys/sa.h>
+#include <sys/sa_impl.h>
+#include <sys/vdev.h>
+#include <sys/vdev_impl.h>
+#include <sys/metaslab_impl.h>
+#include <sys/dmu_objset.h>
+#include <sys/dsl_dir.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dsl_pool.h>
+#include <sys/dsl_bookmark.h>
+#include <sys/dbuf.h>
+#include <sys/zil.h>
+#include <sys/zil_impl.h>
+#include <sys/stat.h>
+#include <sys/resource.h>
+#include <sys/dmu_send.h>
+#include <sys/dmu_traverse.h>
+#include <sys/zio_checksum.h>
+#include <sys/zio_compress.h>
+#include <sys/zfs_fuid.h>
+#include <sys/arc.h>
+#include <sys/arc_impl.h>
+#include <sys/ddt.h>
+#include <sys/zfeature.h>
+#include <sys/abd.h>
+#include <sys/blkptr.h>
+#include <sys/dsl_crypt.h>
+#include <sys/dsl_scan.h>
+#include <sys/btree.h>
+#include <sys/brt.h>
+#include <sys/brt_impl.h>
+#include <zfs_comutil.h>
+#include <sys/zstd/zstd.h>
+
+#include <libnvpair.h>
+#include <libzutil.h>
+
+#include <libzdb.h>
+
+const char *
+zdb_ot_name(dmu_object_type_t type)
+{
+	if (type < DMU_OT_NUMTYPES)
+		return (dmu_ot[type].ot_name);
+	else if ((type & DMU_OT_NEWTYPE) &&
+	    ((type & DMU_OT_BYTESWAP_MASK) < DMU_BSWAP_NUMFUNCS))
+		return (dmu_ot_byteswap[type & DMU_OT_BYTESWAP_MASK].ob_name);
+	else
+		return ("UNKNOWN");
+}
+
+int
+livelist_compare(const void *larg, const void *rarg)
+{
+	const blkptr_t *l = larg;
+	const blkptr_t *r = rarg;
+
+	/* Sort them according to dva[0] */
+	uint64_t l_dva0_vdev, r_dva0_vdev;
+	l_dva0_vdev = DVA_GET_VDEV(&l->blk_dva[0]);
+	r_dva0_vdev = DVA_GET_VDEV(&r->blk_dva[0]);
+	if (l_dva0_vdev < r_dva0_vdev)
+		return (-1);
+	else if (l_dva0_vdev > r_dva0_vdev)
+		return (+1);
+
+	/* if vdevs are equal, sort by offsets. */
+	uint64_t l_dva0_offset;
+	uint64_t r_dva0_offset;
+	l_dva0_offset = DVA_GET_OFFSET(&l->blk_dva[0]);
+	r_dva0_offset = DVA_GET_OFFSET(&r->blk_dva[0]);
+	if (l_dva0_offset < r_dva0_offset) {
+		return (-1);
+	} else if (l_dva0_offset > r_dva0_offset) {
+		return (+1);
+	}
+
+	/*
+	 * Since we're storing blkptrs without cancelling FREE/ALLOC pairs,
+	 * it's possible the offsets are equal. In that case, sort by txg
+	 */
+	if (l->blk_birth < r->blk_birth) {
+		return (-1);
+	} else if (l->blk_birth > r->blk_birth) {
+		return (+1);
+	}
+	return (0);
+}