ctf_open.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

/*
 * 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_open.c	1.7	04/03/20 SMI"

#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 ushort_t
get_kind_v1(ushort_t info)
{
	return (CTF_INFO_KIND_V1(info));
}

static ushort_t
get_kind_v2(ushort_t info)
{
	return (CTF_INFO_KIND(info));
}

static ushort_t
get_root_v1(ushort_t info)
{
	return (CTF_INFO_ISROOT_V1(info));
}

static ushort_t
get_root_v2(ushort_t info)
{
	return (CTF_INFO_ISROOT(info));
}

static ushort_t
get_vlen_v1(ushort_t info)
{
	return (CTF_INFO_VLEN_V1(info));
}

static ushort_t
get_vlen_v2(ushort_t info)
{
	return (CTF_INFO_VLEN(info));
}

static const ctf_fileops_t ctf_fileops[] = {
	{ NULL, NULL },
	{ get_kind_v1, get_root_v1, get_vlen_v1 },
	{ get_kind_v2, get_root_v2, get_vlen_v2 },
};

/*
 * 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;

	ushort_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 += sizeof (ushort_t);
			break;

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

			*xp = funcoff;

			info = *(ushort_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 += sizeof (ushort_t); /* skip pad */
			else
				funcoff += sizeof (ushort_t) * (vlen + 2);
			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 *hp)
{
	/* LINTED - pointer alignment */
	const ctf_type_t *tbuf = (ctf_type_t *)(fp->ctf_buf + hp->cth_typeoff);
	/* LINTED - pointer alignment */
	const ctf_type_t *tend = (ctf_type_t *)(fp->ctf_buf + hp->cth_stroff);

	ulong_t pop[CTF_K_MAX + 1] = { 0 };
	const ctf_type_t *tp;
	ushort_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 = hp->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++) {
		ushort_t kind = LCTF_INFO_KIND(fp, tp->ctt_info);
		ulong_t vlen = LCTF_INFO_VLEN(fp, tp->ctt_info);
		ssize_t size, increment;

		size_t vbytes;
		uint_t n;

		(void) ctf_get_ctt_size(fp, tp, &size, &increment);

		switch (kind) {
		case CTF_K_INTEGER:
		case CTF_K_FLOAT:
			vbytes = sizeof (uint_t);
			break;
		case CTF_K_ARRAY:
			vbytes = sizeof (ctf_array_t);
			break;
		case CTF_K_FUNCTION:
			vbytes = sizeof (ushort_t) * (vlen + (vlen & 1));
			break;
		case CTF_K_STRUCT:
		case CTF_K_UNION:
			if (fp->ctf_version == CTF_VERSION_1 ||
			    size < CTF_LSTRUCT_THRESH) {
				ctf_member_t *mp = (ctf_member_t *)
				    ((uintptr_t)tp + increment);

				vbytes = sizeof (ctf_member_t) * vlen;
				for (n = vlen; n != 0; n--, mp++)
					child |= CTF_TYPE_ISCHILD(mp->ctm_type);
			} else {
				ctf_lmember_t *lmp = (ctf_lmember_t *)
				    ((uintptr_t)tp + increment);

				vbytes = sizeof (ctf_lmember_t) * vlen;
				for (n = vlen; n != 0; n--, lmp++)
					child |=
					    CTF_TYPE_ISCHILD(lmp->ctlm_type);
			}
			break;
		case CTF_K_ENUM:
			vbytes = sizeof (ctf_enum_t) * vlen;
			break;
		case CTF_K_FORWARD:
		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 |= CTF_TYPE_ISCHILD(tp->ctt_type);
			vbytes = 0;
			break;
		default:
			ctf_dprintf("detected invalid CTF kind -- %u\n", kind);
			return (ECTF_CORRUPT);
		}
		tp = (ctf_type_t *)((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] + pop[CTF_K_FORWARD])) != 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 (ushort_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 (ushort_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++) {
		ushort_t kind = LCTF_INFO_KIND(fp, tp->ctt_info);
		ulong_t vlen = LCTF_INFO_VLEN(fp, tp->ctt_info);
		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);
		name = ctf_strptr(fp, tp->ctt_name);

		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,
				    CTF_INDEX_TO_TYPE(id, child), tp->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 = CTF_INDEX_TO_TYPE(id, child);
			}
			vbytes = sizeof (uint_t);
			break;

		case CTF_K_ARRAY:
			vbytes = sizeof (ctf_array_t);
			break;

		case CTF_K_FUNCTION:
			err = ctf_hash_insert(&fp->ctf_names, fp,
			    CTF_INDEX_TO_TYPE(id, child), tp->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);
			vbytes = sizeof (ushort_t) * (vlen + (vlen & 1));
			break;

		case CTF_K_STRUCT:
			/*
			 * If a struct's name is already present as a forward
			 * tag, then replace the tag with the struct definition.
			 */
			if ((hep = ctf_hash_lookup(&fp->ctf_structs, fp,
			    name, strlen(name))) == NULL) {
				err = ctf_hash_insert(&fp->ctf_structs, fp,
				    CTF_INDEX_TO_TYPE(id, child), tp->ctt_name);
				if (err != 0 && err != ECTF_STRTAB)
					return (err);
			} else
				hep->h_type = CTF_INDEX_TO_TYPE(id, child);

			if (fp->ctf_version == CTF_VERSION_1 ||
			    size < CTF_LSTRUCT_THRESH)
				vbytes = sizeof (ctf_member_t) * vlen;
			else {
				vbytes = sizeof (ctf_lmember_t) * vlen;
				nlstructs++;
			}
			break;

		case CTF_K_UNION:
			err = ctf_hash_insert(&fp->ctf_unions, fp,
			    CTF_INDEX_TO_TYPE(id, child), tp->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);

			if (fp->ctf_version == CTF_VERSION_1 ||
			    size < CTF_LSTRUCT_THRESH)
				vbytes = sizeof (ctf_member_t) * vlen;
			else {
				vbytes = sizeof (ctf_lmember_t) * vlen;
				nlunions++;
			}
			break;

		case CTF_K_ENUM:
			err = ctf_hash_insert(&fp->ctf_enums, fp,
			    CTF_INDEX_TO_TYPE(id, child), tp->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,
			    CTF_INDEX_TO_TYPE(id, child), tp->ctt_name);
			if (err != 0 && err != ECTF_STRTAB)
				return (err);
			vbytes = 0;
			break;

		case CTF_K_FORWARD:
			/*
			 * Only insert forward tags into the struct hash if the
			 * struct or tag name is not already present.
			 */
			if (ctf_hash_lookup(&fp->ctf_structs, fp,
			    name, strlen(name)) == NULL) {
				err = ctf_hash_insert(&fp->ctf_structs, fp,
				    CTF_INDEX_TO_TYPE(id, child), tp->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 (CTF_TYPE_ISCHILD(tp->ctt_type) == child &&
			    CTF_TYPE_TO_INDEX(tp->ctt_type) <= fp->ctf_typemax)
				fp->ctf_ptrtab[
				    CTF_TYPE_TO_INDEX(tp->ctt_type)] = id;
			/*FALLTHRU*/

		case CTF_K_VOLATILE:
		case CTF_K_CONST:
		case CTF_K_RESTRICT:
			err = ctf_hash_insert(&fp->ctf_names, fp,
			    CTF_INDEX_TO_TYPE(id, child), tp->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 = (ctf_type_t *)((uintptr_t)tp + increment + vbytes);