ctf_create.c

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/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only.
 * See the file usr/src/LICENSING.NOTICE in this distribution or
 * http://www.opensolaris.org/license/ for details.
 */

#pragma ident	"@(#)ctf_create.c	1.2	04/10/22 SMI"

#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <ctf_impl.h>

/*
 * This static string is used as the template for initially populating a
 * dynamic container's string table.  We always store \0 in the first byte,
 * and we use the generic string "PARENT" to mark this container's parent
 * if one is associated with the container using ctf_import().
 */
static const char _CTF_STRTAB_TEMPLATE[] = "\0PARENT";

/*
 * To create an empty CTF container, we just declare a zeroed header and call
 * ctf_bufopen() on it.  If ctf_bufopen succeeds, we mark the new container r/w
 * and initialize the dynamic members.  We set dtstrlen to 1 to reserve the
 * first byte of the string table for a \0 byte, and we start assigning type
 * IDs at 1 because type ID 0 is used as a sentinel.
 */
ctf_file_t *
ctf_create(int *errp)
{
	static const ctf_header_t hdr = { { CTF_MAGIC, CTF_VERSION, 0 } };

	ctf_sect_t cts;
	ctf_file_t *fp;

	cts.cts_name = _CTF_SECTION;
	cts.cts_type = SHT_PROGBITS;
	cts.cts_flags = 0;
	cts.cts_data = &hdr;
	cts.cts_size = sizeof (hdr);
	cts.cts_entsize = 1;
	cts.cts_offset = 0;

	if ((fp = ctf_bufopen(&cts, NULL, NULL, errp)) != NULL) {
		fp->ctf_flags |= LCTF_RDWR;
		fp->ctf_dtstrlen = sizeof (_CTF_STRTAB_TEMPLATE);
		fp->ctf_dtnextid = 1;
		fp->ctf_dtoldid = 0;
	}

	return (fp);
}

static uchar_t *
ctf_copy_smembers(ctf_dtdef_t *dtd, uint_t soff, uchar_t *t)
{
	ctf_dmdef_t *dmd = ctf_list_next(&dtd->dtd_u.dtu_members);
	ctf_member_t ctm;

	for (; dmd != NULL; dmd = ctf_list_next(dmd)) {
		if (dmd->dmd_name) {
			ctm.ctm_name = soff;
			soff += strlen(dmd->dmd_name) + 1;
		} else
			ctm.ctm_name = 0;

		ctm.ctm_type = (ushort_t)dmd->dmd_type;
		ctm.ctm_offset = (ushort_t)dmd->dmd_offset;

		bcopy(&ctm, t, sizeof (ctm));
		t += sizeof (ctm);
	}

	return (t);
}

static uchar_t *
ctf_copy_lmembers(ctf_dtdef_t *dtd, uint_t soff, uchar_t *t)
{
	ctf_dmdef_t *dmd = ctf_list_next(&dtd->dtd_u.dtu_members);
	ctf_lmember_t ctlm;

	for (; dmd != NULL; dmd = ctf_list_next(dmd)) {
		if (dmd->dmd_name) {
			ctlm.ctlm_name = soff;
			soff += strlen(dmd->dmd_name) + 1;
		} else
			ctlm.ctlm_name = 0;

		ctlm.ctlm_type = (ushort_t)dmd->dmd_type;
		ctlm.ctlm_pad = 0;
		ctlm.ctlm_offsethi = CTF_OFFSET_TO_LMEMHI(dmd->dmd_offset);
		ctlm.ctlm_offsetlo = CTF_OFFSET_TO_LMEMLO(dmd->dmd_offset);

		bcopy(&ctlm, t, sizeof (ctlm));
		t += sizeof (ctlm);
	}

	return (t);
}

static uchar_t *
ctf_copy_emembers(ctf_dtdef_t *dtd, uint_t soff, uchar_t *t)
{
	ctf_dmdef_t *dmd = ctf_list_next(&dtd->dtd_u.dtu_members);
	ctf_enum_t cte;

	for (; dmd != NULL; dmd = ctf_list_next(dmd)) {
		cte.cte_name = soff;
		cte.cte_value = dmd->dmd_value;
		soff += strlen(dmd->dmd_name) + 1;
		bcopy(&cte, t, sizeof (cte));
		t += sizeof (cte);
	}

	return (t);
}

static uchar_t *
ctf_copy_membnames(ctf_dtdef_t *dtd, uchar_t *s)
{
	ctf_dmdef_t *dmd = ctf_list_next(&dtd->dtd_u.dtu_members);
	size_t len;

	for (; dmd != NULL; dmd = ctf_list_next(dmd)) {
		if (dmd->dmd_name == NULL)
			continue; /* skip anonymous members */
		len = strlen(dmd->dmd_name) + 1;
		bcopy(dmd->dmd_name, s, len);
		s += len;
	}

	return (s);
}

/*
 * If the specified CTF container is writable and has been modified, reload
 * this container with the updated type definitions.  In order to make this
 * code and the rest of libctf as simple as possible, we perform updates by
 * taking the dynamic type definitions and creating an in-memory CTF file
 * containing the definitions, and then call ctf_bufopen() on it.  This not
 * only leverages ctf_bufopen(), but also avoids having to bifurcate the rest
 * of the library code with different lookup paths for static and dynamic
 * type definitions.  We are therefore optimizing greatly for lookup over
 * update, which we assume will be an uncommon operation.  We perform one
 * extra trick here for the benefit of callers and to keep our code simple:
 * ctf_bufopen() will return a new ctf_file_t, but we want to keep the fp
 * constant for the caller, so after ctf_bufopen() returns, we use bcopy to
 * swap the interior of the old and new ctf_file_t's, and then free the old.
 */
int
ctf_update(ctf_file_t *fp)
{
	ctf_file_t ofp, *nfp;
	ctf_header_t hdr;
	ctf_dtdef_t *dtd;
	ctf_sect_t cts;

	uchar_t *s, *s0, *t;
	size_t size;
	void *buf;
	int err;

	if (!(fp->ctf_flags & LCTF_RDWR))
		return (ctf_set_errno(fp, ECTF_RDONLY));

	if (!(fp->ctf_flags & LCTF_DIRTY))
		return (0); /* no update required */

	/*
	 * Fill in an initial CTF header.  We will leave the label, object,
	 * and function sections empty and only output a header, type section,
	 * and string table.  The type section begins at a 4-byte aligned
	 * boundary past the CTF header itself (at relative offset zero).
	 */
	bzero(&hdr, sizeof (hdr));
	hdr.cth_magic = CTF_MAGIC;
	hdr.cth_version = CTF_VERSION;

	if (fp->ctf_flags & LCTF_CHILD)
		hdr.cth_parname = 1; /* i.e. _CTF_STRTAB_TEMPLATE[1] */

	/*
	 * Iterate through the dynamic type definition list and compute the
	 * size of the CTF type section we will need to generate.
	 */
	for (size = 0, dtd = ctf_list_next(&fp->ctf_dtdefs);
	    dtd != NULL; dtd = ctf_list_next(dtd)) {

		uint_t kind = CTF_INFO_KIND(dtd->dtd_data.ctt_info);
		uint_t vlen = CTF_INFO_VLEN(dtd->dtd_data.ctt_info);

		if (dtd->dtd_data.ctt_size != CTF_LSIZE_SENT)
			size += sizeof (ctf_stype_t);
		else
			size += sizeof (ctf_type_t);

		switch (kind) {
		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
			size += sizeof (uint_t);
			break;
		case CTF_K_ARRAY:
			size += sizeof (ctf_array_t);
			break;
		case CTF_K_FUNCTION:
			size += sizeof (ushort_t) * (vlen + (vlen & 1));
			break;
		case CTF_K_STRUCT:
		case CTF_K_UNION:
			if (dtd->dtd_data.ctt_size < CTF_LSTRUCT_THRESH)
				size += sizeof (ctf_member_t) * vlen;
			else
				size += sizeof (ctf_lmember_t) * vlen;
			break;
		case CTF_K_ENUM:
			size += sizeof (ctf_enum_t) * vlen;
			break;
		}
	}

	/*
	 * Fill in the string table offset and size, compute the size of the
	 * entire CTF buffer we need, and then allocate a new buffer and
	 * bcopy the finished header to the start of the buffer.
	 */
	hdr.cth_stroff = hdr.cth_typeoff + size;
	hdr.cth_strlen = fp->ctf_dtstrlen;
	size = sizeof (ctf_header_t) + hdr.cth_stroff + hdr.cth_strlen;

	if ((buf = ctf_data_alloc(size)) == MAP_FAILED)
		return (ctf_set_errno(fp, EAGAIN));

	bcopy(&hdr, buf, sizeof (ctf_header_t));
	t = (uchar_t *)buf + sizeof (ctf_header_t);
	s = s0 = (uchar_t *)buf + sizeof (ctf_header_t) + hdr.cth_stroff;

	bcopy(_CTF_STRTAB_TEMPLATE, s, sizeof (_CTF_STRTAB_TEMPLATE));
	s += sizeof (_CTF_STRTAB_TEMPLATE);

	/*
	 * We now take a final lap through the dynamic type definition list and
	 * copy the appropriate type records and strings to the output buffer.
	 */
	for (dtd = ctf_list_next(&fp->ctf_dtdefs);
	    dtd != NULL; dtd = ctf_list_next(dtd)) {

		uint_t kind = CTF_INFO_KIND(dtd->dtd_data.ctt_info);
		uint_t vlen = CTF_INFO_VLEN(dtd->dtd_data.ctt_info);

		ctf_array_t cta;
		uint_t encoding;
		size_t len;

		if (dtd->dtd_name != NULL) {
			dtd->dtd_data.ctt_name = (uint_t)(s - s0);
			len = strlen(dtd->dtd_name) + 1;
			bcopy(dtd->dtd_name, s, len);
			s += len;
		} else
			dtd->dtd_data.ctt_name = 0;

		if (dtd->dtd_data.ctt_size != CTF_LSIZE_SENT)
			len = sizeof (ctf_stype_t);
		else
			len = sizeof (ctf_type_t);

		bcopy(&dtd->dtd_data, t, len);
		t += len;

		switch (kind) {
		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
			if (kind == CTF_K_INTEGER) {
				encoding = CTF_INT_DATA(
				    dtd->dtd_u.dtu_enc.cte_format,
				    dtd->dtd_u.dtu_enc.cte_offset,
				    dtd->dtd_u.dtu_enc.cte_bits);
			} else {
				encoding = CTF_FP_DATA(
				    dtd->dtd_u.dtu_enc.cte_format,
				    dtd->dtd_u.dtu_enc.cte_offset,
				    dtd->dtd_u.dtu_enc.cte_bits);
			}
			bcopy(&encoding, t, sizeof (encoding));
			t += sizeof (encoding);
			break;

		case CTF_K_ARRAY:
			cta.cta_contents = (ushort_t)
			    dtd->dtd_u.dtu_arr.ctr_contents;
			cta.cta_index = (ushort_t)
			    dtd->dtd_u.dtu_arr.ctr_index;
			cta.cta_nelems = dtd->dtd_u.dtu_arr.ctr_nelems;
			bcopy(&cta, t, sizeof (cta));
			t += sizeof (cta);
			break;

		case CTF_K_FUNCTION: {
			ushort_t *argv = (ushort_t *)(uintptr_t)t;
			uint_t argc;

			for (argc = 0; argc < vlen; argc++)
				*argv++ = (ushort_t)dtd->dtd_u.dtu_argv[argc];

			if (vlen & 1)
				*argv++ = 0; /* pad to 4-byte boundary */

			t = (uchar_t *)argv;
			break;
		}

		case CTF_K_STRUCT:
		case CTF_K_UNION:
			if (dtd->dtd_data.ctt_size < CTF_LSTRUCT_THRESH)
				t = ctf_copy_smembers(dtd, (uint_t)(s - s0), t);
			else
				t = ctf_copy_lmembers(dtd, (uint_t)(s - s0), t);
			s = ctf_copy_membnames(dtd, s);
			break;

		case CTF_K_ENUM:
			t = ctf_copy_emembers(dtd, (uint_t)(s - s0), t);
			s = ctf_copy_membnames(dtd, s);
			break;
		}
	}

	/*
	 * Finally, we are ready to ctf_bufopen() the new container.  If this
	 * is successful, we then switch nfp and fp and free the old container.
	 */
	ctf_data_protect(buf, size);
	cts.cts_name = _CTF_SECTION;
	cts.cts_type = SHT_PROGBITS;
	cts.cts_flags = 0;
	cts.cts_data = buf;
	cts.cts_size = size;
	cts.cts_entsize = 1;
	cts.cts_offset = 0;

	if ((nfp = ctf_bufopen(&cts, NULL, NULL, &err)) == NULL) {
		ctf_data_free(buf, size);
		return (ctf_set_errno(fp, err));
	}

	(void) ctf_setmodel(nfp, ctf_getmodel(fp));
	(void) ctf_import(nfp, fp->ctf_parent);

	nfp->ctf_refcnt = fp->ctf_refcnt;
	nfp->ctf_flags |= fp->ctf_flags & ~LCTF_DIRTY;
	nfp->ctf_data.cts_data = NULL; /* force ctf_data_free() on close */
	nfp->ctf_dtdefs = fp->ctf_dtdefs;
	nfp->ctf_dtstrlen = fp->ctf_dtstrlen;
	nfp->ctf_dtnextid = fp->ctf_dtnextid;
	nfp->ctf_dtoldid = fp->ctf_dtnextid - 1;

	bzero(&fp->ctf_dtdefs, sizeof (ctf_list_t));
	bcopy(fp, &ofp, sizeof (ctf_file_t));
	bcopy(nfp, fp, sizeof (ctf_file_t));
	bcopy(&ofp, nfp, sizeof (ctf_file_t));

	/*
	 * 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_bufopen().
	 */
	fp->ctf_lookups[0].ctl_hash = &fp->ctf_structs;
	fp->ctf_lookups[1].ctl_hash = &fp->ctf_unions;
	fp->ctf_lookups[2].ctl_hash = &fp->ctf_enums;
	fp->ctf_lookups[3].ctl_hash = &fp->ctf_names;

	nfp->ctf_refcnt = 1; /* force nfp to be freed */
	ctf_close(nfp);

	return (0);
}

/*
 * Discard all of the dynamic type definitions that have been added to the
 * container since the last call to ctf_update().  We locate such types by
 * scanning the list and deleting elements that have type IDs greater than
 * ctf_dtoldid, which is set by ctf_update(), above.
 */
int
ctf_discard(ctf_file_t *fp)
{
	ctf_dtdef_t *dtd, *ntd;
	ctf_dmdef_t *dmd, *nmd;
	size_t len;

	if (!(fp->ctf_flags & LCTF_RDWR))
		return (ctf_set_errno(fp, ECTF_RDONLY));

	if (!(fp->ctf_flags & LCTF_DIRTY))
		return (0); /* no update required */

	for (dtd = ctf_list_next(&fp->ctf_dtdefs); dtd != NULL; dtd = ntd) {
		if (dtd->dtd_type <= fp->ctf_dtoldid)
			continue; /* skip types that have been committed */

		switch (CTF_INFO_KIND(dtd->dtd_data.ctt_info)) {
		case CTF_K_STRUCT:
		case CTF_K_UNION:
		case CTF_K_ENUM:
			for (dmd = ctf_list_next(&dtd->dtd_u.dtu_members);
			    dmd != NULL; dmd = nmd) {
				if (dmd->dmd_name != NULL) {
					len = strlen(dmd->dmd_name) + 1;
					ctf_free(dmd->dmd_name, len);
					fp->ctf_dtstrlen -= len;