common/mdb/mdb_ctf.c

/*
 * 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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <mdb/mdb_ctf.h>
#include <mdb/mdb_ctf_impl.h>
#include <mdb/mdb_err.h>
#include <mdb/mdb_modapi.h>
#include <mdb/mdb_string.h>
#include <mdb/mdb.h>
#include <mdb/mdb_debug.h>

#include <libctf.h>
#include <string.h>

typedef struct tnarg {
	mdb_tgt_t *tn_tgt;		/* target to use for lookup */
	const char *tn_name;		/* query string to lookup */
	ctf_file_t *tn_fp;		/* CTF container from match */
	ctf_id_t tn_id;			/* CTF type ID from match */
} tnarg_t;

typedef struct type_iter {
	mdb_ctf_type_f *ti_cb;
	void *ti_arg;
	ctf_file_t *ti_fp;
} type_iter_t;

typedef struct member_iter {
	mdb_ctf_member_f *mi_cb;
	void *mi_arg;
	ctf_file_t *mi_fp;
} member_iter_t;

typedef struct type_visit {
	mdb_ctf_visit_f *tv_cb;
	void *tv_arg;
	ctf_file_t *tv_fp;
} type_visit_t;

typedef struct mbr_info {
	const char *mbr_member;
	ulong_t *mbr_offp;
	mdb_ctf_id_t *mbr_typep;
} mbr_info_t;

static void
set_ctf_id(mdb_ctf_id_t *p, ctf_file_t *fp, ctf_id_t id)
{
	mdb_ctf_impl_t *mcip = (mdb_ctf_impl_t *)p;

	mcip->mci_fp = fp;
	mcip->mci_id = id;
}

/*
 * Callback function for mdb_tgt_object_iter used from name_to_type, below,
 * to search the CTF namespace for a given object file.
 */
/*ARGSUSED*/
static int
obj_lookup(void *data, const mdb_map_t *mp, const char *name)
{
	tnarg_t *tnp = data;
	ctf_file_t *fp;
	ctf_id_t id;

	if ((fp = mdb_tgt_name_to_ctf(tnp->tn_tgt, name)) != NULL &&
	    (id = ctf_lookup_by_name(fp, tnp->tn_name)) != CTF_ERR) {
		tnp->tn_fp = fp;
		tnp->tn_id = id;

		/*
		 * We may have found a forward declaration.  If we did, we'll
		 * note the ID and file pointer, but we'll keep searching in
		 * an attempt to find the real thing.  If we found something
		 * real (i.e. not a forward), we stop the iteration.
		 */
		return (ctf_type_kind(fp, id) == CTF_K_FORWARD ? 0 : -1);
	}

	return (0);
}

/*
 * Convert a string type name with an optional leading object specifier into
 * the corresponding CTF file container and type ID.  If an error occurs, we
 * print an appropriate message and return NULL.
 */
static ctf_file_t *
name_to_type(mdb_tgt_t *t, const char *cname, ctf_id_t *idp)
{
	const char *object = MDB_TGT_OBJ_EXEC;
	ctf_file_t *fp = NULL;
	ctf_id_t id;
	tnarg_t arg;
	char *p, *s;
	char buf[MDB_SYM_NAMLEN];
	char *name = &buf[0];

	(void) mdb_snprintf(buf, sizeof (buf), "%s", cname);

	if ((p = strrsplit(name, '`')) != NULL) {
		/*
		 * We need to shuffle things around a little to support
		 * type names of the form "struct module`name".
		 */
		if ((s = strsplit(name, ' ')) != NULL) {
			bcopy(cname + (s - name), name, (p - s) - 1);
			name[(p - s) - 1] = '\0';
			bcopy(cname, name + (p - s), s - name);
			p = name + (p - s);
		}
		if (*name != '\0')
			object = name;
		name = p;
	}

	/*
	 * Attempt to look up the name in the primary object file.  If this
	 * fails and the name was unscoped, search all remaining object files.
	 */
	if (((fp = mdb_tgt_name_to_ctf(t, object)) == NULL ||
	    (id = ctf_lookup_by_name(fp, name)) == CTF_ERR ||
	    ctf_type_kind(fp, id) == CTF_K_FORWARD) &&
	    object == MDB_TGT_OBJ_EXEC) {

		arg.tn_tgt = t;
		arg.tn_name = name;
		arg.tn_fp = NULL;
		arg.tn_id = CTF_ERR;

		(void) mdb_tgt_object_iter(t, obj_lookup, &arg);

		if (arg.tn_id != CTF_ERR) {
			fp = arg.tn_fp;
			id = arg.tn_id;
		}
	}

	if (fp == NULL)
		return (NULL); /* errno is set for us */

	if (id == CTF_ERR) {
		(void) set_errno(ctf_to_errno(ctf_errno(fp)));
		return (NULL);
	}

	*idp = id;
	return (fp);
}

/*
 * Check to see if there is ctf data in the given object. This is useful
 * so that we don't enter some loop where every call to lookup fails.
 */
int
mdb_ctf_enabled_by_object(const char *object)
{
	mdb_tgt_t *t = mdb.m_target;

	return (mdb_tgt_name_to_ctf(t, object) != NULL);
}

int
mdb_ctf_lookup_by_name(const char *name, mdb_ctf_id_t *p)
{
	ctf_file_t *fp = NULL;
	mdb_ctf_impl_t *mcip = (mdb_ctf_impl_t *)p;
	mdb_tgt_t *t = mdb.m_target;

	if (mcip == NULL)
		return (set_errno(EINVAL));

	if ((fp = name_to_type(t, name, &mcip->mci_id)) == NULL) {
		mdb_ctf_type_invalidate(p);
		return (-1); /* errno is set for us */
	}

	mcip->mci_fp = fp;

	return (0);
}

int
mdb_ctf_lookup_by_symbol(const GElf_Sym *symp, const mdb_syminfo_t *sip,
    mdb_ctf_id_t *p)
{
	ctf_file_t *fp = NULL;
	mdb_ctf_impl_t *mcip = (mdb_ctf_impl_t *)p;
	mdb_tgt_t *t = mdb.m_target;

	if (mcip == NULL)
		return (set_errno(EINVAL));

	if (symp == NULL || sip == NULL) {
		mdb_ctf_type_invalidate(p);
		return (set_errno(EINVAL));
	}

	if ((fp = mdb_tgt_addr_to_ctf(t, symp->st_value)) == NULL) {
		mdb_ctf_type_invalidate(p);
		return (-1); /* errno is set for us */
	}

	if ((mcip->mci_id = ctf_lookup_by_symbol(fp, sip->sym_id)) == CTF_ERR) {
		mdb_ctf_type_invalidate(p);
		return (set_errno(ctf_to_errno(ctf_errno(fp))));
	}

	mcip->mci_fp = fp;

	return (0);
}

int
mdb_ctf_lookup_by_addr(uintptr_t addr, mdb_ctf_id_t *p)
{
	GElf_Sym sym;
	mdb_syminfo_t si;
	char name[MDB_SYM_NAMLEN];
	const mdb_map_t *mp;
	mdb_tgt_t *t = mdb.m_target;
	const char *obj, *c;

	if (p == NULL)
		return (set_errno(EINVAL));

	if (mdb_tgt_lookup_by_addr(t, addr, MDB_TGT_SYM_EXACT, name,
	    sizeof (name), NULL, NULL) == -1) {
		mdb_ctf_type_invalidate(p);
		return (-1); /* errno is set for us */
	}

	if ((c = strrsplit(name, '`')) != NULL) {
		obj = name;
	} else {
		if ((mp = mdb_tgt_addr_to_map(t, addr)) == NULL) {
			mdb_ctf_type_invalidate(p);
			return (-1); /* errno is set for us */
		}

		obj = mp->map_name;
		c = name;
	}

	if (mdb_tgt_lookup_by_name(t, obj, c, &sym, &si) == -1) {
		mdb_ctf_type_invalidate(p);
		return (-1); /* errno is set for us */
	}

	return (mdb_ctf_lookup_by_symbol(&sym, &si, p));
}

int
mdb_ctf_module_lookup(const char *name, mdb_ctf_id_t *p)
{
	ctf_file_t *fp;
	ctf_id_t id;
	mdb_module_t *mod;

	if ((mod = mdb_get_module()) == NULL)
		return (set_errno(EMDB_CTX));

	if ((fp = mod->mod_ctfp) == NULL)
		return (set_errno(EMDB_NOCTF));

	if ((id = ctf_lookup_by_name(fp, name)) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(fp))));

	set_ctf_id(p, fp, id);

	return (0);
}

/*ARGSUSED*/
int
mdb_ctf_func_info(const GElf_Sym *symp, const mdb_syminfo_t *sip,
    mdb_ctf_funcinfo_t *mfp)
{
	ctf_file_t *fp = NULL;
	ctf_funcinfo_t f;
	mdb_tgt_t *t = mdb.m_target;
	char name[MDB_SYM_NAMLEN];
	const mdb_map_t *mp;
	mdb_syminfo_t si;
	int err;

	if (symp == NULL || mfp == NULL)
		return (set_errno(EINVAL));

	/*
	 * In case the input symbol came from a merged or private symbol table,
	 * re-lookup the address as a symbol, and then perform a fully scoped
	 * lookup of that symbol name to get the mdb_syminfo_t for its CTF.
	 */
	if ((fp = mdb_tgt_addr_to_ctf(t, symp->st_value)) == NULL ||
	    (mp = mdb_tgt_addr_to_map(t, symp->st_value)) == NULL ||
	    mdb_tgt_lookup_by_addr(t, symp->st_value, MDB_TGT_SYM_FUZZY,
	    name, sizeof (name), NULL, NULL) != 0)
		return (-1); /* errno is set for us */

	if (strchr(name, '`') != NULL)
		err = mdb_tgt_lookup_by_scope(t, name, NULL, &si);
	else
		err = mdb_tgt_lookup_by_name(t, mp->map_name, name, NULL, &si);

	if (err != 0)
		return (-1); /* errno is set for us */

	if (ctf_func_info(fp, si.sym_id, &f) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(fp))));

	set_ctf_id(&mfp->mtf_return, fp, f.ctc_return);
	mfp->mtf_argc = f.ctc_argc;
	mfp->mtf_flags = f.ctc_flags;
	mfp->mtf_symidx = si.sym_id;

	return (0);
}

int
mdb_ctf_func_args(const mdb_ctf_funcinfo_t *funcp, uint_t len,
    mdb_ctf_id_t *argv)
{
	ctf_file_t *fp;
	ctf_id_t cargv[32];
	int i;

	if (len > (sizeof (cargv) / sizeof (cargv[0])))
		return (set_errno(EINVAL));

	if (funcp == NULL || argv == NULL)
		return (set_errno(EINVAL));

	fp = mdb_ctf_type_file(funcp->mtf_return);

	if (ctf_func_args(fp, funcp->mtf_symidx, len, cargv) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(fp))));

	for (i = MIN(len, funcp->mtf_argc) - 1; i >= 0; i--) {
		set_ctf_id(&argv[i], fp, cargv[i]);
	}

	return (0);
}

void
mdb_ctf_type_invalidate(mdb_ctf_id_t *idp)
{
	set_ctf_id(idp, NULL, CTF_ERR);
}

int
mdb_ctf_type_valid(mdb_ctf_id_t id)
{
	return (((mdb_ctf_impl_t *)&id)->mci_id != CTF_ERR);
}

int
mdb_ctf_type_cmp(mdb_ctf_id_t aid, mdb_ctf_id_t bid)
{
	mdb_ctf_impl_t *aidp = (mdb_ctf_impl_t *)&aid;
	mdb_ctf_impl_t *bidp = (mdb_ctf_impl_t *)&bid;

	return (ctf_type_cmp(aidp->mci_fp, aidp->mci_id,
	    bidp->mci_fp, bidp->mci_id));
}

int
mdb_ctf_type_resolve(mdb_ctf_id_t mid, mdb_ctf_id_t *outp)
{
	ctf_id_t id;
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&mid;

	if ((id = ctf_type_resolve(idp->mci_fp, idp->mci_id)) == CTF_ERR) {
		if (outp)
			mdb_ctf_type_invalidate(outp);
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));
	}

	if (outp != NULL)
		set_ctf_id(outp, idp->mci_fp, id);

	return (0);
}

char *
mdb_ctf_type_name(mdb_ctf_id_t id, char *buf, size_t len)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	char *ret;

	if (!mdb_ctf_type_valid(id)) {
		(void) set_errno(EINVAL);
		return (NULL);
	}

	ret = ctf_type_name(idp->mci_fp, idp->mci_id, buf, len);
	if (ret == NULL)
		(void) set_errno(ctf_to_errno(ctf_errno(idp->mci_fp)));

	return (ret);
}

ssize_t
mdb_ctf_type_size(mdb_ctf_id_t id)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	ssize_t ret;

	if ((ret = ctf_type_size(idp->mci_fp, idp->mci_id)) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	return (ret);
}

int
mdb_ctf_type_kind(mdb_ctf_id_t id)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	int ret;

	if ((ret = ctf_type_kind(idp->mci_fp, idp->mci_id)) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	return (ret);
}

int
mdb_ctf_type_reference(mdb_ctf_id_t mid, mdb_ctf_id_t *outp)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&mid;
	ctf_id_t id;

	if ((id = ctf_type_reference(idp->mci_fp, idp->mci_id)) == CTF_ERR) {
		if (outp)
			mdb_ctf_type_invalidate(outp);
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));
	}

	if (outp != NULL)
		set_ctf_id(outp, idp->mci_fp, id);

	return (0);
}


int
mdb_ctf_type_encoding(mdb_ctf_id_t id, ctf_encoding_t *ep)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;

	if (ctf_type_encoding(idp->mci_fp, idp->mci_id, ep) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	return (0);
}

/*
 * callback proxy for mdb_ctf_type_visit
 */
static int
type_cb(const char *name, ctf_id_t type, ulong_t off, int depth, void *arg)
{
	type_visit_t *tvp = arg;
	mdb_ctf_id_t id;

	set_ctf_id(&id, tvp->tv_fp, type);

	return (tvp->tv_cb(name, id, off, depth, tvp->tv_arg));
}

int
mdb_ctf_type_visit(mdb_ctf_id_t id, mdb_ctf_visit_f *func, void *arg)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	type_visit_t tv;
	int ret;

	tv.tv_cb = func;
	tv.tv_arg = arg;
	tv.tv_fp = idp->mci_fp;

	ret = ctf_type_visit(idp->mci_fp, idp->mci_id, type_cb, &tv);

	if (ret == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	return (ret);
}

int
mdb_ctf_array_info(mdb_ctf_id_t id, mdb_ctf_arinfo_t *arp)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	ctf_arinfo_t car;

	if (ctf_array_info(idp->mci_fp, idp->mci_id, &car) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	set_ctf_id(&arp->mta_contents, idp->mci_fp, car.ctr_contents);
	set_ctf_id(&arp->mta_index, idp->mci_fp, car.ctr_index);

	arp->mta_nelems = car.ctr_nelems;

	return (0);
}

const char *
mdb_ctf_enum_name(mdb_ctf_id_t id, int value)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	const char *ret;

	if ((ret = ctf_enum_name(idp->mci_fp, idp->mci_id, value)) == NULL)
		(void) set_errno(ctf_to_errno(ctf_errno(idp->mci_fp)));

	return (ret);
}

/*
 * callback proxy for mdb_ctf_member_iter
 */
static int
member_iter_cb(const char *name, ctf_id_t type, ulong_t off, void *data)
{
	member_iter_t *mip = data;
	mdb_ctf_id_t id;

	set_ctf_id(&id, mip->mi_fp, type);

	return (mip->mi_cb(name, id, off, mip->mi_arg));
}

int
mdb_ctf_member_iter(mdb_ctf_id_t id, mdb_ctf_member_f *cb, void *data)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;
	member_iter_t mi;
	int ret;

	mi.mi_cb = cb;
	mi.mi_arg = data;
	mi.mi_fp = idp->mci_fp;

	ret = ctf_member_iter(idp->mci_fp, idp->mci_id, member_iter_cb, &mi);

	if (ret == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(idp->mci_fp))));

	return (ret);
}

int
mdb_ctf_enum_iter(mdb_ctf_id_t id, mdb_ctf_enum_f *cb, void *data)
{
	mdb_ctf_impl_t *idp = (mdb_ctf_impl_t *)&id;

	return (ctf_enum_iter(idp->mci_fp, idp->mci_id, cb, data));
}

/*
 * callback proxy for mdb_ctf_type_iter
 */
static int
type_iter_cb(ctf_id_t type, void *data)
{
	type_iter_t *tip = data;
	mdb_ctf_id_t id;

	set_ctf_id(&id, tip->ti_fp, type);

	return (tip->ti_cb(id, tip->ti_arg));
}

int
mdb_ctf_type_iter(const char *object, mdb_ctf_type_f *cb, void *data)
{
	ctf_file_t *fp;
	mdb_tgt_t *t = mdb.m_target;
	int ret;
	type_iter_t ti;

	if ((fp = mdb_tgt_name_to_ctf(t, object)) == NULL)
		return (-1);

	ti.ti_cb = cb;
	ti.ti_arg = data;
	ti.ti_fp = fp;

	if ((ret = ctf_type_iter(fp, type_iter_cb, &ti)) == CTF_ERR)
		return (set_errno(ctf_to_errno(ctf_errno(fp))));

	return (ret);
}

/* utility functions */

ctf_id_t
mdb_ctf_type_id(mdb_ctf_id_t id)
{
	return (((mdb_ctf_impl_t *)&id)->mci_id);
}

ctf_file_t *
mdb_ctf_type_file(mdb_ctf_id_t id)
{
	return (((mdb_ctf_impl_t *)&id)->mci_fp);
}

static int
member_info_cb(const char *name, mdb_ctf_id_t id, ulong_t off, void *data)
{
	mbr_info_t *mbrp = data;

	if (strcmp(name, mbrp->mbr_member) == 0) {
		if (mbrp->mbr_offp != NULL)
			*(mbrp->mbr_offp) = off;
		if (mbrp->mbr_typep != NULL)
			*(mbrp->mbr_typep) = id;

		return (1);
	}

	return (0);
}

int
mdb_ctf_member_info(mdb_ctf_id_t id, const char *member, ulong_t *offp,
    mdb_ctf_id_t *typep)
{
	mbr_info_t mbr;
	int rc;

	mbr.mbr_member = member;
	mbr.mbr_offp = offp;
	mbr.mbr_typep = typep;

	rc = mdb_ctf_member_iter(id, member_info_cb, &mbr);

	/* couldn't get member list */
	if (rc == -1)
		return (-1); /* errno is set for us */

	/* not a member */
	if (rc == 0)
		return (set_errno(EMDB_CTFNOMEMB));

	return (0);
}

int
mdb_ctf_offsetof(mdb_ctf_id_t id, const char *member, ulong_t *retp)
{
	return (mdb_ctf_member_info(id, member, retp, NULL));
}

/*ARGSUSED*/
static int
num_members_cb(const char *name, mdb_ctf_id_t id, ulong_t off, void *data)
{
	int *count = data;
	*count = *count + 1;
	return (0);
}

int
mdb_ctf_num_members(mdb_ctf_id_t id)
{
	int count = 0;

	if (mdb_ctf_member_iter(id, num_members_cb, &count) != 0)
		return (-1); /* errno is set for us */

	return (count);
}

typedef struct mbr_contains {
	char **mbc_bufp;
	size_t *mbc_lenp;
	ulong_t *mbc_offp;
	mdb_ctf_id_t *mbc_idp;
	ssize_t mbc_total;
} mbr_contains_t;

static int
offset_to_name_cb(const char *name, mdb_ctf_id_t id, ulong_t off, void *data)
{
	mbr_contains_t *mbc = data;
	ulong_t size;
	ctf_encoding_t e;
	size_t n;

	if (*mbc->mbc_offp < off)
		return (0);

	if (mdb_ctf_type_encoding(id, &e) == -1)
		size = mdb_ctf_type_size(id) * NBBY;
	else
		size = e.cte_bits;

	if (off + size <= *mbc->mbc_offp)
		return (0);

	n = mdb_snprintf(*mbc->mbc_bufp, *mbc->mbc_lenp, "%s", name);
	mbc->mbc_total += n;
	if (n > *mbc->mbc_lenp)
		n = *mbc->mbc_lenp;

	*mbc->mbc_lenp -= n;
	*mbc->mbc_bufp += n;

	*mbc->mbc_offp -= off;
	*mbc->mbc_idp = id;

	return (1);
}

ssize_t
mdb_ctf_offset_to_name(mdb_ctf_id_t id, ulong_t off, char *buf, size_t len,
    int dot, mdb_ctf_id_t *midp, ulong_t *moffp)
{
	size_t size;
	size_t n;
	mbr_contains_t mbc;

	if (!mdb_ctf_type_valid(id))
		return (set_errno(EINVAL));

	/*
	 * Quick sanity check to make sure the given offset is within
	 * this scope of this type.
	 */
	if (mdb_ctf_type_size(id) * NBBY <= off)
		return (set_errno(EINVAL));

	mbc.mbc_bufp = &buf;
	mbc.mbc_lenp = &len;
	mbc.mbc_offp = &off;
	mbc.mbc_idp = &id;
	mbc.mbc_total = 0;

	*buf = '\0';

	for (;;) {
		/*
		 * Check for an exact match.
		 */
		if (off == 0)
			break;

		(void) mdb_ctf_type_resolve(id, &id);

		/*
		 * Find the member that contains this offset.
		 */
		switch (mdb_ctf_type_kind(id)) {
		case CTF_K_ARRAY: {
			mdb_ctf_arinfo_t ar;
			uint_t index;

			(void) mdb_ctf_array_info(id, &ar);
			size = mdb_ctf_type_size(ar.mta_contents) * NBBY;
			index = off / size;

			id = ar.mta_contents;
			off %= size;

			n = mdb_snprintf(buf, len, "[%u]", index);
			mbc.mbc_total += n;
			if (n > len)
				n = len;

			buf += n;
			len -= n;
			break;
		}

		case CTF_K_STRUCT: {
			int ret;

			/*
			 * Find the member that contains this offset
			 * and continue.
			 */

			if (dot) {
				mbc.mbc_total++;
				if (len != 0) {
					*buf++ = '.';
					*buf = '\0';
					len--;
				}
			}

			ret = mdb_ctf_member_iter(id, offset_to_name_cb, &mbc);
			if (ret == -1)
				return (-1); /* errno is set for us */

			/*
			 * If we did not find a member containing this offset
			 * (due to holes in the structure), return EINVAL.
			 */
			if (ret == 0)
				return (set_errno(EINVAL));

			break;
		}

		case CTF_K_UNION:
			/*
			 * Treat unions like atomic entities since we can't
			 * do more than guess which member of the union
			 * might be the intended one.
			 */
			goto done;

		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
		case CTF_K_POINTER:
		case CTF_K_ENUM:
			goto done;

		default:
			return (set_errno(EINVAL));
		}

		dot = 1;
	}
done:
	if (midp != NULL)
		*midp = id;
	if (moffp != NULL)
		*moffp = off;

	return (mbc.mbc_total);
}

/*
 * Check if two types are structurally the same rather than logically
 * the same. That is to say that two types are equal if they have the
 * same logical structure rather than having the same ids in CTF-land.
 */
static int type_equals(mdb_ctf_id_t, mdb_ctf_id_t);

static int
type_equals_cb(const char *name, mdb_ctf_id_t amem, ulong_t aoff, void *data)
{
	mdb_ctf_id_t b = *(mdb_ctf_id_t *)data;
	ulong_t boff;
	mdb_ctf_id_t bmem;

	/*
	 * Look up the corresponding member in the other composite type.
	 */
	if (mdb_ctf_member_info(b, name, &boff, &bmem) != 0)
		return (1);

	/*
	 * We don't allow members to be shuffled around.
	 */
	if (aoff != boff)
		return (1);

	return (type_equals(amem, bmem) ? 0 : 1);
}

static int
type_equals(mdb_ctf_id_t a, mdb_ctf_id_t b)
{
	size_t asz, bsz;
	int akind, bkind;
	mdb_ctf_arinfo_t aar, bar;

	/*
	 * Resolve both types down to their fundamental types, and make
	 * sure their sizes and kinds match.
	 */
	if (mdb_ctf_type_resolve(a, &a) != 0 ||
	    mdb_ctf_type_resolve(b, &b) != 0 ||
	    (asz = mdb_ctf_type_size(a)) == -1UL ||
	    (bsz = mdb_ctf_type_size(b)) == -1UL ||
	    (akind = mdb_ctf_type_kind(a)) == -1 ||
	    (bkind = mdb_ctf_type_kind(b)) == -1 ||
	    asz != bsz || akind != bkind) {
		return (0);
	}

	switch (akind) {
	case CTF_K_INTEGER:
	case CTF_K_FLOAT:
	case CTF_K_POINTER:
		/*
		 * For pointers we could be a little stricter and require
		 * both pointers to reference types which look vaguely
		 * similar (for example, we could insist that the two types
		 * have the same name). However, all we really care about
		 * here is that the structure of the two types are the same,
		 * and, in that regard, one pointer is as good as another.
		 */
		return (1);

	case CTF_K_UNION:
	case CTF_K_STRUCT:
		/*
		 * The test for the number of members is only strictly
		 * necessary for unions since we'll find other problems with
		 * structs. However, the extra check will do no harm.
		 */
		return (mdb_ctf_num_members(a) == mdb_ctf_num_members(b) &&
		    mdb_ctf_member_iter(a, type_equals_cb, &b) == 0);

	case CTF_K_ARRAY:
		return (mdb_ctf_array_info(a, &aar) == 0 &&
		    mdb_ctf_array_info(b, &bar) == 0 &&
		    aar.mta_nelems == bar.mta_nelems &&
		    type_equals(aar.mta_index, bar.mta_index) &&
		    type_equals(aar.mta_contents, bar.mta_contents));
	}

	return (0);
}


typedef struct member {
	char		*m_modbuf;
	char		*m_tgtbuf;
	mdb_ctf_id_t	m_tgtid;
	uint_t		m_flags;
} member_t;

static int vread_helper(mdb_ctf_id_t, char *, mdb_ctf_id_t, char *, uint_t);

static int
member_cb(const char *name, mdb_ctf_id_t modmid, ulong_t modoff, void *data)
{
	member_t *mp = data;
	char *modbuf = mp->m_modbuf;
	mdb_ctf_id_t tgtmid;
	char *tgtbuf = mp->m_tgtbuf;
	ulong_t tgtoff;

	if (mdb_ctf_member_info(mp->m_tgtid, name, &tgtoff, &tgtmid) != 0) {
		if (mp->m_flags & MDB_CTF_VREAD_IGNORE_ABSENT)
			return (0);
		else
			return (set_errno(EMDB_CTFNOMEMB));
	}

	return (vread_helper(modmid, modbuf + modoff / NBBY,
	    tgtmid, tgtbuf + tgtoff / NBBY, mp->m_flags));
}


static int
vread_helper(mdb_ctf_id_t modid, char *modbuf,
    mdb_ctf_id_t tgtid, char *tgtbuf, uint_t flags)
{
	size_t modsz, tgtsz;
	int modkind, tgtkind;
	member_t mbr;
	int ret;
	mdb_ctf_arinfo_t tar, mar;
	int i;

	/*
	 * Resolve the types to their canonical form.
	 */
	(void) mdb_ctf_type_resolve(modid, &modid);
	(void) mdb_ctf_type_resolve(tgtid, &tgtid);

	if ((modkind = mdb_ctf_type_kind(modid)) == -1)
		return (-1); /* errno is set for us */
	if ((tgtkind = mdb_ctf_type_kind(tgtid)) == -1)
		return (-1); /* errno is set for us */

	if (tgtkind != modkind)
		return (set_errno(EMDB_INCOMPAT));

	switch (modkind) {
	case CTF_K_INTEGER:
	case CTF_K_FLOAT:
	case CTF_K_POINTER:
		if ((modsz = mdb_ctf_type_size(modid)) == -1UL)
			return (-1); /* errno is set for us */

		if ((tgtsz = mdb_ctf_type_size(tgtid)) == -1UL)
			return (-1); /* errno is set for us */

		/*
		 * If the sizes don't match we need to be tricky to make
		 * sure that the caller gets the correct data.
		 */
		if (modsz < tgtsz) {
			if (!(flags & MDB_CTF_VREAD_IGNORE_GROW))
				return (set_errno(EMDB_INCOMPAT));
#ifdef _BIG_ENDIAN
			bcopy(tgtbuf + tgtsz - modsz, modbuf, modsz);
#else
			bcopy(tgtbuf, modbuf, modsz);
#endif
		} else if (modsz > tgtsz) {
			bzero(modbuf, modsz);
#ifdef _BIG_ENDIAN
			bcopy(tgtbuf, modbuf + modsz - tgtsz, tgtsz);
#else
			bcopy(tgtbuf, modbuf, tgtsz);
#endif
		} else {
			bcopy(tgtbuf, modbuf, modsz);
		}

		return (0);

	case CTF_K_STRUCT:
		mbr.m_modbuf = modbuf;
		mbr.m_tgtbuf = tgtbuf;
		mbr.m_tgtid = tgtid;
		mbr.m_flags = flags;

		return (mdb_ctf_member_iter(modid, member_cb, &mbr));

	case CTF_K_UNION:

		/*
		 * Unions are a little tricky. The only time it's truly
		 * safe to read in a union is if no part of the union or
		 * any of its component types have changed. We allow the
		 * consumer to ignore unions. The correct use of this
		 * feature is to read the containing structure, figure
		 * out which component of the union is valid, compute
		 * the location of that in the target and then read in
		 * that part of the structure.
		 */
		if (flags & MDB_CTF_VREAD_IGNORE_UNIONS)
			return (0);

		if (!type_equals(modid, tgtid))
			return (set_errno(EMDB_INCOMPAT));

		modsz = mdb_ctf_type_size(modid);
		tgtsz = mdb_ctf_type_size(tgtid);

		ASSERT(modsz == tgtsz);

		bcopy(tgtbuf, modbuf, modsz);

		return (0);

	case CTF_K_ARRAY:
		if (mdb_ctf_array_info(tgtid, &tar) != 0)
			return (-1); /* errno is set for us */
		if (mdb_ctf_array_info(modid, &mar) != 0)
			return (-1); /* errno is set for us */

		if (tar.mta_nelems != mar.mta_nelems)
			return (set_errno(EMDB_INCOMPAT));

		if ((modsz = mdb_ctf_type_size(mar.mta_contents)) == -1UL)
			return (-1); /* errno is set for us */

		if ((tgtsz = mdb_ctf_type_size(tar.mta_contents)) == -1UL)
			return (-1); /* errno is set for us */

		for (i = 0; i < tar.mta_nelems; i++) {
			ret = vread_helper(mar.mta_contents, modbuf + i * modsz,
			    tar.mta_contents, tgtbuf + i * tgtsz, flags);

			if (ret != 0)
				return (ret);
		}

		return (0);
	}

	return (set_errno(EMDB_INCOMPAT));
}


int
mdb_ctf_vread(void *modbuf, const char *typename, uintptr_t addr, uint_t flags)
{
	ctf_file_t *mfp;
	ctf_id_t mid;
	void *tgtbuf;
	size_t size;
	mdb_ctf_id_t tgtid;
	mdb_ctf_id_t modid;
	mdb_module_t *mod;

	if ((mod = mdb_get_module()) == NULL || (mfp = mod->mod_ctfp) == NULL)
		return (set_errno(EMDB_NOCTF));

	if ((mid = ctf_lookup_by_name(mfp, typename)) == CTF_ERR) {
		mdb_dprintf(MDB_DBG_CTF, "couldn't find module's ctf data\n");
		return (set_errno(ctf_to_errno(ctf_errno(mfp))));
	}

	set_ctf_id(&modid, mfp, mid);

	if (mdb_ctf_lookup_by_name(typename, &tgtid) != 0) {
		mdb_dprintf(MDB_DBG_CTF, "couldn't find target's ctf data\n");
		return (set_errno(EMDB_NOCTF));
	}

	/*
	 * Read the data out of the target's address space.
	 */
	if ((size = mdb_ctf_type_size(tgtid)) == -1UL)
		return (-1); /* errno is set for us */

	tgtbuf = mdb_alloc(size, UM_SLEEP | UM_GC);

	if (mdb_vread(tgtbuf, size, addr) < 0)
		return (-1); /* errno is set for us */

	return (vread_helper(modid, modbuf, tgtid, tgtbuf, flags));
}

int
mdb_ctf_readsym(void *buf, const char *typename, const char *name, uint_t flags)
{
	GElf_Sym sym;

	if (mdb_lookup_by_name(name, &sym) != 0)
		return (-1); /* errno is set for us */

	return (mdb_ctf_vread(buf, typename, sym.st_value, flags));
}

ctf_file_t *
mdb_ctf_bufopen(const void *ctf_va, size_t ctf_size, const void *sym_va,
    Shdr *symhdr, const void *str_va, Shdr *strhdr, int *errp)
{
	ctf_sect_t ctdata, symtab, strtab;

	ctdata.cts_name = ".SUNW_ctf";
	ctdata.cts_type = SHT_PROGBITS;
	ctdata.cts_flags = 0;
	ctdata.cts_data = ctf_va;
	ctdata.cts_size = ctf_size;
	ctdata.cts_entsize = 1;
	ctdata.cts_offset = 0;

	symtab.cts_name = ".symtab";
	symtab.cts_type = symhdr->sh_type;
	symtab.cts_flags = symhdr->sh_flags;
	symtab.cts_data = sym_va;
	symtab.cts_size = symhdr->sh_size;
	symtab.cts_entsize = symhdr->sh_entsize;
	symtab.cts_offset = symhdr->sh_offset;

	strtab.cts_name = ".strtab";
	strtab.cts_type = strhdr->sh_type;
	strtab.cts_flags = strhdr->sh_flags;
	strtab.cts_data = str_va;
	strtab.cts_size = strhdr->sh_size;
	strtab.cts_entsize = strhdr->sh_entsize;
	strtab.cts_offset = strhdr->sh_offset;

	return (ctf_bufopen(&ctdata, &symtab, &strtab, errp));
}