xref: /freebsd/cddl/contrib/opensolaris/common/ctf/ctf_open.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
 */

#include <ctf_impl.h>
#include <sys/mman.h>
#include <sys/zmod.h>

static const ctf_dmodel_t _libctf_models[] = {
	{ "ILP32", CTF_MODEL_ILP32, 4, 1, 2, 4, 4 },
	{ "LP64", CTF_MODEL_LP64, 8, 1, 2, 4, 8 },
	{ NULL, 0, 0, 0, 0, 0, 0 }
};

const char _CTF_SECTION[] = ".SUNW_ctf";
const char _CTF_NULLSTR[] = "";

int _libctf_version = CTF_VERSION;	/* library client version */
int _libctf_debug = 0;			/* debugging messages enabled */

static uint_t
get_kind_v2(uint_t info)
{
	return (CTF_V2_INFO_KIND((ushort_t)info));
}

static uint_t
get_root_v2(uint_t info)
{
	return (CTF_V2_INFO_ISROOT((ushort_t)info));
}

static uint_t
get_vlen_v2(uint_t info)
{
	return (CTF_V2_INFO_VLEN((ushort_t)info));
}

static uint_t
get_max_vlen_v2(void)
{
	return (CTF_V2_MAX_VLEN);
}

static uint_t
get_max_size_v2(void)
{
	return (CTF_V2_MAX_SIZE);
}

static uint_t
get_max_type_v2(void)
{
	return (CTF_V2_MAX_TYPE);
}

static uint_t
get_lsize_sent_v2(void)
{
	return (CTF_V2_LSIZE_SENT);
}

static uint_t
get_lstruct_thresh_v2(void)
{
	return (CTF_V2_LSTRUCT_THRESH);
}

static uint_t
type_info_v2(uint_t kind, uint_t isroot, uint_t len)
{
	return (CTF_V2_TYPE_INFO(kind, isroot, len));
}

static int
type_isparent_v2(uint_t id)
{
	return (CTF_V2_TYPE_ISPARENT(id));
}

static int
type_ischild_v2(uint_t id)
{
	return (CTF_V2_TYPE_ISCHILD(id));
}

static uint_t
type_to_index_v2(uint_t t)
{
	return (CTF_V2_TYPE_TO_INDEX(t));
}

static uint_t
index_to_type_v2(uint_t id, uint_t child)
{
	return (CTF_V2_INDEX_TO_TYPE(id, child));
}

static uint_t
get_kind_v3(uint_t info)
{
	return (CTF_V3_INFO_KIND(info));
}

static uint_t
get_root_v3(uint_t info)
{
	return (CTF_V3_INFO_ISROOT(info));
}

static uint_t
get_vlen_v3(uint_t info)
{
	return (CTF_V3_INFO_VLEN(info));
}

static uint_t
get_max_vlen_v3(void)
{
	return (CTF_V3_MAX_VLEN);
}

static uint_t
get_max_size_v3(void)
{
	return (CTF_V3_MAX_SIZE);
}

static uint_t
get_max_type_v3(void)
{
	return (CTF_V3_MAX_TYPE);
}

static uint_t
get_lsize_sent_v3(void)
{
	return (CTF_V3_LSIZE_SENT);
}

static uint_t
get_lstruct_thresh_v3(void)
{
	return (CTF_V3_LSTRUCT_THRESH);
}

static uint_t
type_info_v3(uint_t kind, uint_t isroot, uint_t len)
{
	return (CTF_V3_TYPE_INFO(kind, isroot, len));
}

static int
type_isparent_v3(uint_t id)
{
	return (CTF_V3_TYPE_ISPARENT(id));
}

static int
type_ischild_v3(uint_t id)
{
	return (CTF_V3_TYPE_ISCHILD(id));
}

static uint_t
type_to_index_v3(uint_t t)
{
	return (CTF_V3_TYPE_TO_INDEX(t));
}

static uint_t
index_to_type_v3(uint_t id, uint_t child)
{
	return (CTF_V3_INDEX_TO_TYPE(id, child));
}

#define	CTF_FILEOPS_ENTRY(v)				\
	{ 						\
	  .ctfo_get_kind = get_kind_v ## v,		\
	  .ctfo_get_root = get_root_v ## v,		\
	  .ctfo_get_vlen = get_vlen_v ## v,		\
	  .ctfo_get_max_vlen = get_max_vlen_v ## v,	\
	  .ctfo_get_max_size = get_max_size_v ## v,	\
	  .ctfo_get_max_type = get_max_type_v ## v,	\
	  .ctfo_get_lsize_sent = get_lsize_sent_v ## v,	\
	  .ctfo_get_lstruct_thresh = get_lstruct_thresh_v ## v,	\
	  .ctfo_type_info = type_info_v ## v,		\
	  .ctfo_type_isparent = type_isparent_v ## v,	\
	  .ctfo_type_ischild = type_ischild_v ## v,	\
	  .ctfo_type_to_index = type_to_index_v ## v,	\
	  .ctfo_index_to_type = index_to_type_v ## v	\
	}

static const ctf_fileops_t ctf_fileops[] = {
	{ NULL, NULL },
	{ NULL, NULL },
	CTF_FILEOPS_ENTRY(2),
	CTF_FILEOPS_ENTRY(3),
};

/*
 * Convert a 32-bit ELF symbol into GElf (Elf64) and return a pointer to it.
 */
static Elf64_Sym *
sym_to_gelf(const Elf32_Sym *src, Elf64_Sym *dst)
{
	dst->st_name = src->st_name;
	dst->st_value = src->st_value;
	dst->st_size = src->st_size;
	dst->st_info = src->st_info;
	dst->st_other = src->st_other;
	dst->st_shndx = src->st_shndx;

	return (dst);
}

/*
 * Initialize the symtab translation table by filling each entry with the
 * offset of the CTF type or function data corresponding to each STT_FUNC or
 * STT_OBJECT entry in the symbol table.
 */
static int
init_symtab(ctf_file_t *fp, const ctf_header_t *hp,
    const ctf_sect_t *sp, const ctf_sect_t *strp)
{
	const uchar_t *symp = sp->cts_data;
	uint_t *xp = fp->ctf_sxlate;
	uint_t *xend = xp + fp->ctf_nsyms;

	uint_t objtoff = hp->cth_objtoff;
	uint_t funcoff = hp->cth_funcoff;

	uint_t info, vlen;

	Elf64_Sym sym, *gsp;
	const char *name;

	/*
	 * The CTF data object and function type sections are ordered to match
	 * the relative order of the respective symbol types in the symtab.
	 * If no type information is available for a symbol table entry, a
	 * pad is inserted in the CTF section.  As a further optimization,
	 * anonymous or undefined symbols are omitted from the CTF data.
	 */
	for (; xp < xend; xp++, symp += sp->cts_entsize) {
		if (sp->cts_entsize == sizeof (Elf32_Sym))
			gsp = sym_to_gelf((Elf32_Sym *)(uintptr_t)symp, &sym);
		else
			gsp = (Elf64_Sym *)(uintptr_t)symp;

		if (gsp->st_name < strp->cts_size)
			name = (const char *)strp->cts_data + gsp->st_name;
		else
			name = _CTF_NULLSTR;

		if (gsp->st_name == 0 || gsp->st_shndx == SHN_UNDEF ||
		    strcmp(name, "_START_") == 0 ||
		    strcmp(name, "_END_") == 0) {
			*xp = -1u;
			continue;
		}

		switch (ELF64_ST_TYPE(gsp->st_info)) {
		case STT_OBJECT:
			if (objtoff >= hp->cth_funcoff ||
			    (gsp->st_shndx == SHN_ABS && gsp->st_value == 0)) {
				*xp = -1u;
				break;
			}

			*xp = objtoff;
			objtoff += fp->ctf_idwidth;
			break;

		case STT_FUNC:
			if (funcoff >= hp->cth_typeoff) {
				*xp = -1u;
				break;
			}

			*xp = funcoff;

			info = *(uint_t *)((uintptr_t)fp->ctf_buf + funcoff);
			vlen = LCTF_INFO_VLEN(fp, info);

			/*
			 * If we encounter a zero pad at the end, just skip it.
			 * Otherwise skip over the function and its return type
			 * (+2) and the argument list (vlen).
			 */
			if (LCTF_INFO_KIND(fp, info) == CTF_K_UNKNOWN &&
			    vlen == 0)
				funcoff += fp->ctf_idwidth;
			else
				funcoff +=
				    roundup2(fp->ctf_idwidth * (vlen + 2), 4);
			break;

		default:
			*xp = -1u;
			break;
		}
	}

	ctf_dprintf("loaded %lu symtab entries\n", fp->ctf_nsyms);
	return (0);
}

/*
 * Initialize the type ID translation table with the byte offset of each type,
 * and initialize the hash tables of each named type.
 */
static int
init_types(ctf_file_t *fp, const ctf_header_t *cth)
{
	const void *tbuf = (const void *)(fp->ctf_buf + cth->cth_typeoff);
	const void *tend = (const void *)(fp->ctf_buf + cth->cth_stroff);

	ulong_t pop[CTF_K_MAX + 1] = { 0 };
	const void *tp;
	ctf_hash_t *hp;
	uint_t id, dst;
	uint_t *xp;

	/*
	 * We initially determine whether the container is a child or a parent
	 * based on the value of cth_parname.  To support containers that pre-
	 * date cth_parname, we also scan the types themselves for references
	 * to values in the range reserved for child types in our first pass.
	 */
	int child = cth->cth_parname != 0;
	int nlstructs = 0, nlunions = 0;
	int err;

	/*
	 * We make two passes through the entire type section.  In this first
	 * pass, we count the number of each type and the total number of types.
	 */
	for (tp = tbuf; tp < tend; fp->ctf_typemax++) {
		ssize_t size, increment;

		size_t vbytes;
		uint_t kind, n, type, vlen;

		(void) ctf_get_ctt_size(fp, tp, &size, &increment);
		ctf_get_ctt_info(fp, tp, &kind, &vlen, NULL);
		ctf_get_ctt_index(fp, tp, NULL, &type, NULL);

		switch (kind) {
		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
			vbytes = sizeof (uint_t);
			break;
		case CTF_K_ARRAY:
			if (fp->ctf_version == CTF_VERSION_2)
				vbytes = sizeof (struct ctf_array_v2);
			else
				vbytes = sizeof (struct ctf_array_v3);
			break;
		case CTF_K_FUNCTION:
			vbytes = roundup2(fp->ctf_idwidth * vlen, 4);
			break;
		case CTF_K_STRUCT:
		case CTF_K_UNION: {
			size_t increment1;
			uint_t type;
			const void *mp =
			    (const void *)((uintptr_t)tp + increment);

			vbytes = 0;
			for (n = vlen; n != 0; n--, mp += increment1) {
				ctf_get_ctm_info(fp, mp, size, &increment1, &type,
				    NULL, NULL);
				child |= LCTF_TYPE_ISCHILD(fp, type);
				vbytes += increment1;
			}
			break;
		}
		case CTF_K_ENUM:
			vbytes = sizeof (ctf_enum_t) * vlen;
			break;
		case CTF_K_FORWARD:
			/*
			 * For forward declarations, ctt_type is the CTF_K_*
			 * kind for the tag, so bump that population count too.
			 * If ctt_type is unknown, treat the tag as a struct.
			 */
			if (type == CTF_K_UNKNOWN || type >= CTF_K_MAX)
				pop[CTF_K_STRUCT]++;
			else
				pop[type]++;
			/*FALLTHRU*/
		case CTF_K_UNKNOWN:
			vbytes = 0;
			break;
		case CTF_K_POINTER:
		case CTF_K_TYPEDEF:
		case CTF_K_VOLATILE:
		case CTF_K_CONST:
		case CTF_K_RESTRICT:
			child |= LCTF_TYPE_ISCHILD(fp, type);
			vbytes = 0;
			break;
		default:
			ctf_dprintf("detected invalid CTF kind -- %u\n", kind);
			return (ECTF_CORRUPT);
		}
		tp = (const void *)((uintptr_t)tp + increment + vbytes);
		pop[kind]++;
	}

	/*
	 * If we detected a reference to a child type ID, then we know this
	 * container is a child and may have a parent's types imported later.
	 */
	if (child) {
		ctf_dprintf("CTF container %p is a child\n", (void *)fp);
		fp->ctf_flags |= LCTF_CHILD;
	} else
		ctf_dprintf("CTF container %p is a parent\n", (void *)fp);

	/*
	 * Now that we've counted up the number of each type, we can allocate
	 * the hash tables, type translation table, and pointer table.
	 */
	if ((err = ctf_hash_create(&fp->ctf_structs, pop[CTF_K_STRUCT])) != 0)
		return (err);

	if ((err = ctf_hash_create(&fp->ctf_unions, pop[CTF_K_UNION])) != 0)
		return (err);

	if ((err = ctf_hash_create(&fp->ctf_enums, pop[CTF_K_ENUM])) != 0)
		return (err);

	if ((err = ctf_hash_create(&fp->ctf_names,
	    pop[CTF_K_INTEGER] + pop[CTF_K_FLOAT] + pop[CTF_K_FUNCTION] +
	    pop[CTF_K_TYPEDEF] + pop[CTF_K_POINTER] + pop[CTF_K_VOLATILE] +
	    pop[CTF_K_CONST] + pop[CTF_K_RESTRICT])) != 0)
		return (err);

	fp->ctf_txlate = ctf_alloc(sizeof (uint_t) * (fp->ctf_typemax + 1));
	fp->ctf_ptrtab = ctf_alloc(sizeof (uint_t) * (fp->ctf_typemax + 1));

	if (fp->ctf_txlate == NULL || fp->ctf_ptrtab == NULL)
		return (EAGAIN); /* memory allocation failed */

	xp = fp->ctf_txlate;
	*xp++ = 0; /* type id 0 is used as a sentinel value */

	bzero(fp->ctf_txlate, sizeof (uint_t) * (fp->ctf_typemax + 1));
	bzero(fp->ctf_ptrtab, sizeof (uint_t) * (fp->ctf_typemax + 1));

	/*
	 * In the second pass through the types, we fill in each entry of the
	 * type and pointer tables and add names to the appropriate hashes.
	 */
	for (id = 1, tp = tbuf; tp < tend; xp++, id++) {
		const struct ctf_type_v3 *ctt = tp;
		uint_t kind, type, vlen;
		ssize_t size, increment;

		const char *name;
		size_t vbytes;
		ctf_helem_t *hep;
		ctf_encoding_t cte;

		(void) ctf_get_ctt_size(fp, tp, &size, &increment);
		ctf_get_ctt_info(fp, tp, &kind, &vlen, NULL);
		ctf_get_ctt_index(fp, tp, NULL, &type, NULL);
		name = ctf_type_rname(fp, tp);

		switch (kind) {
		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
			/*
			 * Only insert a new integer base type definition if
			 * this type name has not been defined yet.  We re-use
			 * the names with different encodings for bit-fields.
			 */
			if ((hep = ctf_hash_lookup(&fp->ctf_names, fp,
			    name, strlen(name))) == NULL) {
				err = ctf_hash_insert(&fp->ctf_names, fp,
				    LCTF_INDEX_TO_TYPE(fp, id, child),
				    ctt->ctt_name);
				if (err != 0 && err != ECTF_STRTAB)
					return (err);
			} else if (ctf_type_encoding(fp, hep->h_type,
			    &cte) == 0 && cte.cte_bits == 0) {
				/*
				 * Work-around SOS8 stabs bug: replace existing
				 * intrinsic w/ same name if it was zero bits.
				 */
				hep->h_type = LCTF_INDEX_TO_TYPE(fp, id, child);
			}
			vbytes = sizeof (uint_t);
			break;

		case CTF_K_ARRAY:
			if (fp->ctf_version == CTF_VERSION_2)
				vbytes = sizeof (struct ctf_array_v2);
			else
				vbytes = sizeof (struct ctf_array_v3);
			break;

		case CTF_K_FUNCTION:
			err = ctf_hash_insert(&fp->ctf_names, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);
			vbytes = roundup2(fp->ctf_idwidth * vlen, 4);
			break;

		case CTF_K_STRUCT:
			err = ctf_hash_define(&fp->ctf_structs, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);

			if (err != 0 && err != ECTF_STRTAB)
				return (err);

			if (fp->ctf_version == CTF_VERSION_2) {
				if (size < LCTF_LSTRUCT_THRESH(fp))
					vbytes = sizeof (struct ctf_member_v2) *
					    vlen;
				else {
					vbytes =
					    sizeof (struct ctf_lmember_v2) *
					    vlen;
					nlstructs++;
				}
			} else {
				if (size < LCTF_LSTRUCT_THRESH(fp))
					vbytes = sizeof (struct ctf_member_v3) *
					    vlen;
				else {
					vbytes =
					    sizeof (struct ctf_lmember_v3) *
					    vlen;
					nlstructs++;
				}
			}
			break;

		case CTF_K_UNION:
			err = ctf_hash_define(&fp->ctf_unions, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);

			if (err != 0 && err != ECTF_STRTAB)
				return (err);

			if (fp->ctf_version == CTF_VERSION_2) {
				if (size < LCTF_LSTRUCT_THRESH(fp))
					vbytes = sizeof (struct ctf_member_v2) *
					    vlen;
				else {
					vbytes =
					    sizeof (struct ctf_lmember_v2) *
					    vlen;
					nlunions++;
				}
			} else {
				if (size < LCTF_LSTRUCT_THRESH(fp))
					vbytes = sizeof (struct ctf_member_v3) *
					    vlen;
				else {
					vbytes =
					    sizeof (struct ctf_lmember_v3) *
					    vlen;
					nlunions++;
				}
			}
			break;

		case CTF_K_ENUM:
			err = ctf_hash_define(&fp->ctf_enums, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);

			if (err != 0 && err != ECTF_STRTAB)
				return (err);

			vbytes = sizeof (ctf_enum_t) * vlen;
			break;

		case CTF_K_TYPEDEF:
			err = ctf_hash_insert(&fp->ctf_names, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);
			vbytes = 0;
			break;

		case CTF_K_FORWARD:
			/*
			 * Only insert forward tags into the given hash if the
			 * type or tag name is not already present.
			 */
			switch (type) {
			case CTF_K_STRUCT:
				hp = &fp->ctf_structs;
				break;
			case CTF_K_UNION:
				hp = &fp->ctf_unions;
				break;
			case CTF_K_ENUM:
				hp = &fp->ctf_enums;
				break;
			default:
				hp = &fp->ctf_structs;
			}

			if (ctf_hash_lookup(hp, fp,
			    name, strlen(name)) == NULL) {
				err = ctf_hash_insert(hp, fp,
				    LCTF_INDEX_TO_TYPE(fp, id, child),
				    ctt->ctt_name);
				if (err != 0 && err != ECTF_STRTAB)
					return (err);
			}
			vbytes = 0;
			break;

		case CTF_K_POINTER:
			/*
			 * If the type referenced by the pointer is in this CTF
			 * container, then store the index of the pointer type
			 * in fp->ctf_ptrtab[ index of referenced type ].
			 */
			if (LCTF_TYPE_ISCHILD(fp, type) == child &&
			    LCTF_TYPE_TO_INDEX(fp, type) <= fp->ctf_typemax)
				fp->ctf_ptrtab[
				    LCTF_TYPE_TO_INDEX(fp, type)] = id;
			/*FALLTHRU*/

		case CTF_K_VOLATILE:
		case CTF_K_CONST:
		case CTF_K_RESTRICT:
			err = ctf_hash_insert(&fp->ctf_names, fp,
			    LCTF_INDEX_TO_TYPE(fp, id, child), ctt->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);
			/*FALLTHRU*/

		default:
			vbytes = 0;
			break;
		}

		*xp = (uint_t)((uintptr_t)tp - (uintptr_t)fp->ctf_buf);
		tp = (const void *)((uintptr_t)tp + increment + vbytes);
	}

	ctf_dprintf("%lu total types processed\n", fp->ctf_typemax);
	ctf_dprintf("%u enum names hashed\n", ctf_hash_size(&fp->ctf_enums));
	ctf_dprintf("%u struct names hashed (%d long)\n",
	    ctf_hash_size(&fp->ctf_structs), nlstructs);
	ctf_dprintf("%u union names hashed (%d long)\n",
	    ctf_hash_size(&fp->ctf_unions), nlunions);
	ctf_dprintf("%u base type names hashed\n",
	    ctf_hash_size(&fp->ctf_names));

	/*
	 * Make an additional pass through the pointer table to find pointers
	 * that point to anonymous typedef nodes.  If we find one, modify the
	 * pointer table so that the pointer is also known to point to the
	 * node that is referenced by the anonymous typedef node.
	 */
	for (id = 1; id <= fp->ctf_typemax; id++) {
		if ((dst = fp->ctf_ptrtab[id]) != 0) {
			uint_t index, kind;
			int ischild;

			tp = LCTF_INDEX_TO_TYPEPTR(fp, id);
			ctf_get_ctt_info(fp, tp, &kind, NULL, NULL);
			ctf_get_ctt_index(fp, tp, &index, NULL, &ischild);

			if (kind == CTF_K_TYPEDEF &&
			    strcmp(ctf_type_rname(fp, tp), "") == 0 &&
			    ischild == child && index <= fp->ctf_typemax)
				fp->ctf_ptrtab[index] = dst;
		}
	}

	return (0);
}

/*
 * Decode the specified CTF buffer and optional symbol table and create a new
 * CTF container representing the symbolic debugging information.  This code
 * can be used directly by the debugger, or it can be used as the engine for
 * ctf_fdopen() or ctf_open(), below.
 */
ctf_file_t *
ctf_bufopen(const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
    const ctf_sect_t *strsect, int *errp)
{
	const ctf_preamble_t *pp;
	ctf_header_t hp;
	ctf_file_t *fp;
	void *buf, *base;
	size_t size, hdrsz;
	int err;

	if (ctfsect == NULL || ((symsect == NULL) != (strsect == NULL)))
		return (ctf_set_open_errno(errp, EINVAL));

	if (symsect != NULL && symsect->cts_entsize != sizeof (Elf32_Sym) &&
	    symsect->cts_entsize != sizeof (Elf64_Sym))
		return (ctf_set_open_errno(errp, ECTF_SYMTAB));

	if (symsect != NULL && symsect->cts_data == NULL)
		return (ctf_set_open_errno(errp, ECTF_SYMBAD));

	if (strsect != NULL && strsect->cts_data == NULL)
		return (ctf_set_open_errno(errp, ECTF_STRBAD));

	if (ctfsect->cts_size < sizeof (ctf_preamble_t))
		return (ctf_set_open_errno(errp, ECTF_NOCTFBUF));

	pp = (const ctf_preamble_t *)ctfsect->cts_data;

	ctf_dprintf("ctf_bufopen: magic=0x%x version=%u\n",
	    pp->ctp_magic, pp->ctp_version);

	/*
	 * Validate each part of the CTF header (either V1 or V2).
	 * First, we validate the preamble (common to all versions).  At that
	 * point, we know specific header version, and can validate the
	 * version-specific parts including section offsets and alignments.
	 */
	if (pp->ctp_magic != CTF_MAGIC)
		return (ctf_set_open_errno(errp, ECTF_NOCTFBUF));

	if (pp->ctp_version == CTF_VERSION_2 ||
	    pp->ctp_version == CTF_VERSION_3) {
		if (ctfsect->cts_size < sizeof (ctf_header_t))
			return (ctf_set_open_errno(errp, ECTF_NOCTFBUF));

		bcopy(ctfsect->cts_data, &hp, sizeof (hp));
		hdrsz = sizeof (ctf_header_t);

	} else
		return (ctf_set_open_errno(errp, ECTF_CTFVERS));

	size = hp.cth_stroff + hp.cth_strlen;

	ctf_dprintf("ctf_bufopen: uncompressed size=%lu\n", (ulong_t)size);

	if (hp.cth_lbloff > size || hp.cth_objtoff > size ||
	    hp.cth_funcoff > size || hp.cth_typeoff > size ||
	    hp.cth_stroff > size)
		return (ctf_set_open_errno(errp, ECTF_CORRUPT));

	if (hp.cth_lbloff > hp.cth_objtoff ||
	    hp.cth_objtoff > hp.cth_funcoff ||
	    hp.cth_funcoff > hp.cth_typeoff ||
	    hp.cth_typeoff > hp.cth_stroff)
		return (ctf_set_open_errno(errp, ECTF_CORRUPT));

	if ((hp.cth_lbloff & 3) || (hp.cth_objtoff & 1) ||
	    (hp.cth_funcoff & 1) || (hp.cth_typeoff & 3))
		return (ctf_set_open_errno(errp, ECTF_CORRUPT));

	/*
	 * Once everything is determined to be valid, attempt to decompress
	 * the CTF data buffer if it is compressed.  Otherwise we just put
	 * the data section's buffer pointer into ctf_buf, below.
	 */
	if (hp.cth_flags & CTF_F_COMPRESS) {
		size_t srclen, dstlen;
		const void *src;
		int rc = Z_OK;

		if (ctf_zopen(errp) == NULL)
			return (NULL); /* errp is set for us */

		if ((base = ctf_data_alloc(size + hdrsz)) == MAP_FAILED)
			return (ctf_set_open_errno(errp, ECTF_ZALLOC));

		bcopy(ctfsect->cts_data, base, hdrsz);
		((ctf_preamble_t *)base)->ctp_flags &= ~CTF_F_COMPRESS;
		buf = (uchar_t *)base + hdrsz;

		src = (uchar_t *)ctfsect->cts_data + hdrsz;
		srclen = ctfsect->cts_size - hdrsz;
		dstlen = size;

		if ((rc = z_uncompress(buf, &dstlen, src, srclen)) != Z_OK) {
			ctf_dprintf("zlib inflate err: %s\n", z_strerror(rc));
			ctf_data_free(base, size + hdrsz);
			return (ctf_set_open_errno(errp, ECTF_DECOMPRESS));
		}

		if (dstlen != size) {
			ctf_dprintf("zlib inflate short -- got %lu of %lu "
			    "bytes\n", (ulong_t)dstlen, (ulong_t)size);
			ctf_data_free(base, size + hdrsz);
			return (ctf_set_open_errno(errp, ECTF_CORRUPT));
		}

		ctf_data_protect(base, size + hdrsz);

	} else {
		base = (void *)ctfsect->cts_data;
		buf = (uchar_t *)base + hdrsz;
	}

	/*
	 * Once we have uncompressed and validated the CTF data buffer, we can
	 * proceed with allocating a ctf_file_t and initializing it.
	 */
	if ((fp = ctf_alloc(sizeof (ctf_file_t))) == NULL)
		return (ctf_set_open_errno(errp, EAGAIN));

	bzero(fp, sizeof (ctf_file_t));
	fp->ctf_version = hp.cth_version;
	fp->ctf_idwidth = fp->ctf_version == CTF_VERSION_2 ? 2 : 4;
	fp->ctf_fileops = &ctf_fileops[hp.cth_version];
	bcopy(ctfsect, &fp->ctf_data, sizeof (ctf_sect_t));

	if (symsect != NULL) {
		bcopy(symsect, &fp->ctf_symtab, sizeof (ctf_sect_t));
		bcopy(strsect, &fp->ctf_strtab, sizeof (ctf_sect_t));
	}

	if (fp->ctf_data.cts_name != NULL)
		fp->ctf_data.cts_name = ctf_strdup(fp->ctf_data.cts_name);
	if (fp->ctf_symtab.cts_name != NULL)
		fp->ctf_symtab.cts_name = ctf_strdup(fp->ctf_symtab.cts_name);
	if (fp->ctf_strtab.cts_name != NULL)
		fp->ctf_strtab.cts_name = ctf_strdup(fp->ctf_strtab.cts_name);

	if (fp->ctf_data.cts_name == NULL)
		fp->ctf_data.cts_name = _CTF_NULLSTR;
	if (fp->ctf_symtab.cts_name == NULL)
		fp->ctf_symtab.cts_name = _CTF_NULLSTR;
	if (fp->ctf_strtab.cts_name == NULL)
		fp->ctf_strtab.cts_name = _CTF_NULLSTR;

	fp->ctf_str[CTF_STRTAB_0].cts_strs = (const char *)buf + hp.cth_stroff;
	fp->ctf_str[CTF_STRTAB_0].cts_len = hp.cth_strlen;

	if (strsect != NULL) {
		fp->ctf_str[CTF_STRTAB_1].cts_strs = strsect->cts_data;
		fp->ctf_str[CTF_STRTAB_1].cts_len = strsect->cts_size;
	}

	fp->ctf_base = base;
	fp->ctf_buf = buf;
	fp->ctf_size = size + hdrsz;

	/*
	 * If we have a parent container name and label, store the relocated
	 * string pointers in the CTF container for easy access later.
	 */
	if (hp.cth_parlabel != 0)
		fp->ctf_parlabel = ctf_strptr(fp, hp.cth_parlabel);
	if (hp.cth_parname != 0)
		fp->ctf_parname = ctf_strptr(fp, hp.cth_parname);

	ctf_dprintf("ctf_bufopen: parent name %s (label %s)\n",
	    fp->ctf_parname ? fp->ctf_parname : "<NULL>",
	    fp->ctf_parlabel ? fp->ctf_parlabel : "<NULL>");

	/*
	 * If we have a symbol table section, allocate and initialize
	 * the symtab translation table, pointed to by ctf_sxlate.
	 */
	if (symsect != NULL) {
		fp->ctf_nsyms = symsect->cts_size / symsect->cts_entsize;
		fp->ctf_sxlate = ctf_alloc(fp->ctf_nsyms * sizeof (uint_t));

		if (fp->ctf_sxlate == NULL) {
			(void) ctf_set_open_errno(errp, EAGAIN);
			goto bad;
		}

		if ((err = init_symtab(fp, &hp, symsect, strsect)) != 0) {
			(void) ctf_set_open_errno(errp, err);
			goto bad;
		}
	}

	if ((err = init_types(fp, &hp)) != 0) {
		(void) ctf_set_open_errno(errp, err);
		goto bad;
	}

	/*
	 * Initialize the ctf_lookup_by_name top-level dictionary.  We keep an
	 * array of type name prefixes and the corresponding ctf_hash to use.
	 * NOTE: This code must be kept in sync with the code in ctf_update().
	 */
	fp->ctf_lookups[0].ctl_prefix = "struct";
	fp->ctf_lookups[0].ctl_len = strlen(fp->ctf_lookups[0].ctl_prefix);
	fp->ctf_lookups[0].ctl_hash = &fp->ctf_structs;
	fp->ctf_lookups[1].ctl_prefix = "union";
	fp->ctf_lookups[1].ctl_len = strlen(fp->ctf_lookups[1].ctl_prefix);
	fp->ctf_lookups[1].ctl_hash = &fp->ctf_unions;
	fp->ctf_lookups[2].ctl_prefix = "enum";
	fp->ctf_lookups[2].ctl_len = strlen(fp->ctf_lookups[2].ctl_prefix);
	fp->ctf_lookups[2].ctl_hash = &fp->ctf_enums;
	fp->ctf_lookups[3].ctl_prefix = _CTF_NULLSTR;
	fp->ctf_lookups[3].ctl_len = strlen(fp->ctf_lookups[3].ctl_prefix);
	fp->ctf_lookups[3].ctl_hash = &fp->ctf_names;
	fp->ctf_lookups[4].ctl_prefix = NULL;
	fp->ctf_lookups[4].ctl_len = 0;
	fp->ctf_lookups[4].ctl_hash = NULL;

	if (symsect != NULL) {
		if (symsect->cts_entsize == sizeof (Elf64_Sym))
			(void) ctf_setmodel(fp, CTF_MODEL_LP64);
		else
			(void) ctf_setmodel(fp, CTF_MODEL_ILP32);
	} else
		(void) ctf_setmodel(fp, CTF_MODEL_NATIVE);

	fp->ctf_refcnt = 1;
	return (fp);

bad:
	ctf_close(fp);
	return (NULL);
}

/*
 * Dupliate a ctf_file_t and its underlying section information into a new
 * container. This works by copying the three ctf_sect_t's of the original
 * container if they exist and passing those into ctf_bufopen. To copy those, we
 * mmap anonymous memory with ctf_data_alloc and bcopy the data across. It's not
 * the cheapest thing, but it's what we've got.
 */
ctf_file_t *
ctf_dup(ctf_file_t *ofp)
{
	ctf_file_t *fp;
	ctf_sect_t ctfsect, symsect, strsect;
	ctf_sect_t *ctp, *symp, *strp;
	void *cbuf, *symbuf, *strbuf;
	int err;

	cbuf = symbuf = strbuf = NULL;
	/*
	 * The ctfsect isn't allowed to not exist, but the symbol and string
	 * section might not. We only need to copy the data of the section, not
	 * the name, as ctf_bufopen will take care of that.
	 */
	bcopy(&ofp->ctf_data, &ctfsect, sizeof (ctf_sect_t));
	cbuf = ctf_data_alloc(ctfsect.cts_size);
	if (cbuf == NULL) {
		(void) ctf_set_errno(ofp, ECTF_MMAP);
		return (NULL);
	}

	bcopy(ctfsect.cts_data, cbuf, ctfsect.cts_size);
	ctf_data_protect(cbuf, ctfsect.cts_size);
	ctfsect.cts_data = cbuf;
	ctfsect.cts_offset = 0;
	ctp = &ctfsect;

	if (ofp->ctf_symtab.cts_data != NULL) {
		bcopy(&ofp->ctf_symtab, &symsect, sizeof (ctf_sect_t));
		symbuf = ctf_data_alloc(symsect.cts_size);
		if (symbuf == NULL) {
			(void) ctf_set_errno(ofp, ECTF_MMAP);
			goto err;
		}
		bcopy(symsect.cts_data, symbuf, symsect.cts_size);
		ctf_data_protect(symbuf, symsect.cts_size);
		symsect.cts_data = symbuf;
		symsect.cts_offset = 0;
		symp = &symsect;
	} else {
		symp = NULL;
	}

	if (ofp->ctf_strtab.cts_data != NULL) {
		bcopy(&ofp->ctf_strtab, &strsect, sizeof (ctf_sect_t));
		strbuf = ctf_data_alloc(strsect.cts_size);
		if (strbuf == NULL) {
			(void) ctf_set_errno(ofp, ECTF_MMAP);
			goto err;
		}
		bcopy(strsect.cts_data, strbuf, strsect.cts_size);
		ctf_data_protect(strbuf, strsect.cts_size);
		strsect.cts_data = strbuf;
		strsect.cts_offset = 0;
		strp = &strsect;
	} else {
		strp = NULL;
	}

	fp = ctf_bufopen(ctp, symp, strp, &err);
	if (fp == NULL) {
		(void) ctf_set_errno(ofp, err);
		goto err;
	}

	fp->ctf_flags |= LCTF_MMAP;

	return (fp);

err:
	ctf_data_free(cbuf, ctfsect.cts_size);
	if (symbuf != NULL)
		ctf_data_free(symbuf, symsect.cts_size);
	if (strbuf != NULL)
		ctf_data_free(strbuf, strsect.cts_size);
	return (NULL);
}

/*
 * Close the specified CTF container and free associated data structures.  Note
 * that ctf_close() is a reference counted operation: if the specified file is
 * the parent of other active containers, its reference count will be greater
 * than one and it will be freed later when no active children exist.
 */
void
ctf_close(ctf_file_t *fp)
{
	ctf_dtdef_t *dtd, *ntd;

	if (fp == NULL)
		return; /* allow ctf_close(NULL) to simplify caller code */

	ctf_dprintf("ctf_close(%p) refcnt=%u\n", (void *)fp, fp->ctf_refcnt);

	if (fp->ctf_refcnt > 1) {
		fp->ctf_refcnt--;
		return;
	}

	if (fp->ctf_parent != NULL)
		ctf_close(fp->ctf_parent);

	/*
	 * Note, to work properly with reference counting on the dynamic
	 * section, we must delete the list in reverse.
	 */
	for (dtd = ctf_list_prev(&fp->ctf_dtdefs); dtd != NULL; dtd = ntd) {
		ntd = ctf_list_prev(dtd);
		ctf_dtd_delete(fp, dtd);
	}

	ctf_free(fp->ctf_dthash, fp->ctf_dthashlen * sizeof (ctf_dtdef_t *));

	if (fp->ctf_flags & LCTF_MMAP) {
		if (fp->ctf_data.cts_data != NULL)
			ctf_sect_munmap(&fp->ctf_data);
		if (fp->ctf_symtab.cts_data != NULL)
			ctf_sect_munmap(&fp->ctf_symtab);
		if (fp->ctf_strtab.cts_data != NULL)
			ctf_sect_munmap(&fp->ctf_strtab);
	}

	if (fp->ctf_data.cts_name != _CTF_NULLSTR &&
	    fp->ctf_data.cts_name != NULL) {
		ctf_free((char *)fp->ctf_data.cts_name,
		    strlen(fp->ctf_data.cts_name) + 1);
	}

	if (fp->ctf_symtab.cts_name != _CTF_NULLSTR &&
	    fp->ctf_symtab.cts_name != NULL) {
		ctf_free((char *)fp->ctf_symtab.cts_name,
		    strlen(fp->ctf_symtab.cts_name) + 1);
	}

	if (fp->ctf_strtab.cts_name != _CTF_NULLSTR &&
	    fp->ctf_strtab.cts_name != NULL) {
		ctf_free((char *)fp->ctf_strtab.cts_name,
		    strlen(fp->ctf_strtab.cts_name) + 1);
	}

	if (fp->ctf_base != fp->ctf_data.cts_data && fp->ctf_base != NULL)
		ctf_data_free((void *)fp->ctf_base, fp->ctf_size);

	if (fp->ctf_sxlate != NULL)
		ctf_free(fp->ctf_sxlate, sizeof (uint_t) * fp->ctf_nsyms);

	if (fp->ctf_txlate != NULL) {
		ctf_free(fp->ctf_txlate,
		    sizeof (uint_t) * (fp->ctf_typemax + 1));
	}

	if (fp->ctf_ptrtab != NULL) {
		ctf_free(fp->ctf_ptrtab,
		    sizeof (uint_t) * (fp->ctf_typemax + 1));
	}

	ctf_hash_destroy(&fp->ctf_structs);
	ctf_hash_destroy(&fp->ctf_unions);
	ctf_hash_destroy(&fp->ctf_enums);
	ctf_hash_destroy(&fp->ctf_names);

	ctf_free(fp, sizeof (ctf_file_t));
}

/*
 * Return the CTF handle for the parent CTF container, if one exists.
 * Otherwise return NULL to indicate this container has no imported parent.
 */
ctf_file_t *
ctf_parent_file(ctf_file_t *fp)
{
	return (fp->ctf_parent);
}

/*
 * Return the name of the parent CTF container, if one exists.  Otherwise
 * return NULL to indicate this container is a root container.
 */
const char *
ctf_parent_name(ctf_file_t *fp)
{
	return (fp->ctf_parname);
}

/*
 * Import the types from the specified parent container by storing a pointer
 * to it in ctf_parent and incrementing its reference count.  Only one parent
 * is allowed: if a parent already exists, it is replaced by the new parent.
 */
int
ctf_import(ctf_file_t *fp, ctf_file_t *pfp)
{
	if (fp == NULL || fp == pfp || (pfp != NULL && pfp->ctf_refcnt == 0))
		return (ctf_set_errno(fp, EINVAL));

	if (pfp != NULL && pfp->ctf_dmodel != fp->ctf_dmodel)
		return (ctf_set_errno(fp, ECTF_DMODEL));

	if (fp->ctf_parent != NULL)
		ctf_close(fp->ctf_parent);

	if (pfp != NULL) {
		fp->ctf_flags |= LCTF_CHILD;
		pfp->ctf_refcnt++;
	}

	fp->ctf_parent = pfp;
	return (0);
}

/*
 * Set the data model constant for the CTF container.
 */
int
ctf_setmodel(ctf_file_t *fp, int model)
{
	const ctf_dmodel_t *dp;

	for (dp = _libctf_models; dp->ctd_name != NULL; dp++) {
		if (dp->ctd_code == model) {
			fp->ctf_dmodel = dp;
			return (0);
		}
	}

	return (ctf_set_errno(fp, EINVAL));
}

/*
 * Return the data model constant for the CTF container.
 */
int
ctf_getmodel(ctf_file_t *fp)
{
	return (fp->ctf_dmodel->ctd_code);
}

void
ctf_setspecific(ctf_file_t *fp, void *data)
{
	fp->ctf_specific = data;
}

void *
ctf_getspecific(ctf_file_t *fp)
{
	return (fp->ctf_specific);
}