lib/libtnfctl/sym.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 (c) 1994, by Sun Microsytems, Inc.
 */

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

/*
 * Routines that
 *  - return an address for a symbol name
 *  - return a symbol name for an address
 */

#ifndef DEBUG
#define NDEBUG  1
#endif

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/procfs.h>
#include <sys/stat.h>
#include <assert.h>
#include <note.h>

#include "tnfctl_int.h"
#include "dbg.h"


/*
 * Typedefs
 */

typedef struct sym_args {
    char        *sa_name;
    uintptr_t   sa_addr;
} sym_args_t;
NOTE(SCHEME_PROTECTS_DATA("always automatic", sym_args))

/*
 * Declarations
 */

static tnfctl_errcode_t sym_findname_in_obj(int objfd, uintptr_t baseaddr,
    uintptr_t symaddr, char **symname);

static tnfctl_errcode_t sym_match(char *name, uintptr_t addr, void *sym_entry,
    tnfctl_elf_search_t *search_info_p);

static tnfctl_errcode_t sym_matchname(char *name, uintptr_t addr,
    void *sym_entry,
    tnfctl_elf_search_t *search_info_p);


/* ---------------------------------------------------------------- */
/* ----------------------- Public Functions ----------------------- */
/* ---------------------------------------------------------------- */

/*
 * _tnfctl_sym_find_in_obj() - determines the virtual address of the supplied
 * symbol in the object file specified by fd.
 */
tnfctl_errcode_t
_tnfctl_sym_find_in_obj(int objfd, uintptr_t baseaddr, const char *symname,
        uintptr_t *symaddr)
{
    tnfctl_errcode_t    prexstat = TNFCTL_ERR_NONE;
    sym_args_t      symargs;
    tnfctl_elf_search_t search_info;

    DBG_TNF_PROBE_1(_tnfctl_sym_find_in_obj_1, "libtnfctl",
            "sunw%verbosity 3",
            tnf_string, searching_for, symname);

    symargs.sa_name = (char *) symname;
    /* clear output argument in advance */
    symargs.sa_addr = 0;

    search_info.section_func = _tnfctl_traverse_dynsym;
    search_info.record_func = sym_match;
    search_info.record_data = &symargs;

    prexstat = _tnfctl_traverse_object(objfd, baseaddr, &search_info);
    if (prexstat)
        return (prexstat);

    /* check if we found symbol address */
    if (symargs.sa_addr == 0) {
        return (TNFCTL_ERR_BADARG);
    }

    *symaddr = symargs.sa_addr;
    return (TNFCTL_ERR_NONE);
}


/*
 * _tnfctl_sym_find() - determines the virtual address of the supplied symbol
 * in the process.
 */
tnfctl_errcode_t
_tnfctl_sym_find(tnfctl_handle_t *hndl, const char *symname, uintptr_t *symaddr)
{
    boolean_t   release_lock;
    tnfctl_errcode_t    prexstat = TNFCTL_ERR_NONE;
    objlist_t   *obj;

    DBG_TNF_PROBE_1(_tnfctl_sym_find_start, "libtnfctl",
            "start _tnfctl_sym_find; sunw%verbosity 3",
            tnf_string, searching_for, symname);

    /*LINTED statement has no consequent: else*/
    LOCK(hndl, prexstat, release_lock);

    /* for every object in list, search for symbol */
    for (obj = hndl->objlist; obj; obj = obj->next) {
        if (obj->old == B_TRUE)
            continue;   /* don't examine dlclose'd libs */

        /* return value of TNFCTL_ERR_BADARG means symbol not found */
        prexstat = _tnfctl_sym_find_in_obj(obj->objfd,
            obj->baseaddr, symname, symaddr);
        if (prexstat == TNFCTL_ERR_NONE)
            /* symbol found */
            break;
        else if (prexstat != TNFCTL_ERR_BADARG)
            /* error condition */
            break;
        /* continue loop on TNFCTL_ERR_BADARG */
    }

    /*LINTED statement has no consequent: else*/
    UNLOCK(hndl, release_lock);

    DBG_TNF_PROBE_0(_tnfctl_sym_find_end, "libtnfctl",
            "end _tnfctl_sym_find; sunw%verbosity 3");

    return (prexstat);
}

/*
 * _tnfctl_sym_obj_find() - determines the virtual address of the supplied
 *  symbol in the object specified by base name
 */
tnfctl_errcode_t
_tnfctl_sym_obj_find(tnfctl_handle_t *hndl, const char *lib_base_name,
    const char *symname, uintptr_t *symaddr)
{
    tnfctl_errcode_t    prexstat = TNFCTL_ERR_NONE;
    objlist_t   *obj, *found_obj;
    const char *str_ptr;

    assert((hndl->mode == INTERNAL_MODE) ?
        (MUTEX_HELD(&_tnfctl_lmap_lock)) : 1);

    DBG_TNF_PROBE_1(_tnfctl_sym_obj_find_start, "libtnfctl",
            "start _tnfctl_sym_obj_find; sunw%verbosity 3",
            tnf_string, searching_for, symname);

    found_obj = NULL;
    /* for every object in list ... */
    for (obj = hndl->objlist; obj; obj = obj->next) {
        if (obj->old == B_TRUE)
            continue;   /* don't examine dlclose'd libs */

        if (obj->objname == NULL)
            continue;

        /* find the last occurrence of / in the name */
        str_ptr = strrchr(obj->objname, '/');
        if (str_ptr == NULL) {
            str_ptr = obj->objname;
        } else {
            str_ptr++;  /* bump up past '/' */
        }

        /* XXX - use strcoll ? */
        if (strcmp(str_ptr, lib_base_name) == 0) {
            found_obj = obj;
            break;
        }
    }
    /* return value of TNFCTL_ERR_BADARG means symbol not found */
    if (found_obj == NULL)
        return (TNFCTL_ERR_BADARG);

    prexstat = _tnfctl_sym_find_in_obj(found_obj->objfd,
            found_obj->baseaddr, symname, symaddr);

    DBG_TNF_PROBE_0(_tnfctl_sym_obj_find_end, "libtnfctl",
            "end _tnfctl_sym_obj_find; sunw%verbosity 3");

    return (prexstat);
}

/*
 * _tnfctl_sym_findname() - determines the name of a function from its address.
 */
tnfctl_errcode_t
_tnfctl_sym_findname(tnfctl_handle_t *hndl, uintptr_t symaddr,
    char **symname)
{
    boolean_t   release_lock;
    tnfctl_errcode_t    prexstat = TNFCTL_ERR_NONE;
    objlist_t   *obj;

    DBG_TNF_PROBE_1(_tnfctl_sym_findname_start, "libtnfctl",
            "start _tnfctl_sym_findname; sunw%verbosity 3",
            tnf_opaque, searching_for, symaddr);

    /*LINTED statement has no consequent: else*/
    LOCK(hndl, prexstat, release_lock);

    /* for every object in list, search for name */
    for (obj = hndl->objlist; obj; obj = obj->next) {
        if (obj->old == B_TRUE)
            continue;   /* don't examine dlclose'd libs */
        /* return value of TNFCTL_ERR_BADARG means symbol not found */
        prexstat = sym_findname_in_obj(obj->objfd,
            obj->baseaddr, symaddr, symname);
        if (prexstat == TNFCTL_ERR_NONE)
            /* symbol found */
            break;
        else if (prexstat != TNFCTL_ERR_BADARG)
            /* error condition */
            break;
        /* continue loop on TNFCTL_ERR_BADARG */
    }

    /*LINTED statement has no consequent: else*/
    UNLOCK(hndl, release_lock);

    DBG_TNF_PROBE_0(_tnfctl_sym_findname_end, "libtnfctl",
            "end _tnfctl_sym_findname; sunw%verbosity 3");

    return (prexstat);
}


/* ---------------------------------------------------------------- */
/* ----------------------- Private Functions ---------------------- */
/* ---------------------------------------------------------------- */

/*
 * sym_findname_in_obj() - determines the name of the supplied
 * address in the specified object file.
 */
static tnfctl_errcode_t
sym_findname_in_obj(int objfd, uintptr_t baseaddr, uintptr_t symaddr,
    char **symname)
{
    tnfctl_errcode_t    prexstat = TNFCTL_ERR_NONE;
    sym_args_t  symargs;
    tnfctl_elf_search_t search_info;

    DBG_TNF_PROBE_1(sym_findname_in_obj_1, "libtnfctl",
            "sunw%verbosity 3",
            tnf_opaque, searching_for, symaddr);

    /* clear output argument in advance */
    symargs.sa_name = NULL;
    symargs.sa_addr = symaddr;

    search_info.section_func = _tnfctl_traverse_dynsym;
    search_info.record_func = sym_matchname;
    search_info.record_data = &symargs;

    prexstat = _tnfctl_traverse_object(objfd, baseaddr, &search_info);
    if (prexstat)
        return (prexstat);

    /* check if we found symbol address */
    if (symargs.sa_name == NULL) {
        return (TNFCTL_ERR_BADARG);
    }

    *symname = symargs.sa_name;
    return (TNFCTL_ERR_NONE);
}

/*
 * sym_match() - function to be called on each symbol in a dynsym section.
 *      Used to find the address of a symbol.
 */
static tnfctl_errcode_t
sym_match(char *name, uintptr_t addr, void *sym_entry,
    tnfctl_elf_search_t *search_info_p)
{
    sym_args_t  *symargs_p = (sym_args_t *) search_info_p->record_data;
    Elf3264_Sym *sym = (Elf3264_Sym *) sym_entry;
#if 0
    printf("enter sym_match: \n");
    if (symargs_p->sa_name != 0)
        printf("(symargs_p->sa_name) = %s\n", symargs_p->sa_name);
    else
        printf("symargs_p->sa_name = 0\n");
    if (name != 0)
        printf("(name) = %s\n", name);
    else
        printf("name = 0\n");
#endif

#ifdef VERYVERBOSE
    (void) fprintf(stderr, "sym_match: checking \"%s\"\n", name);
#endif

    if ((sym->st_shndx != SHN_UNDEF) &&
            (strcmp(name, symargs_p->sa_name) == 0)) {

        DBG_TNF_PROBE_2(sym_match_1, "libtnfctl",
            "sunw%verbosity 2; sunw%debug '\tMatched Symbol'",
            tnf_string, symbol, name,
            tnf_opaque, address_found, addr);

        symargs_p->sa_addr = addr;
    }
#if 0
    printf("leaving sym_match\n");
#endif
    return (TNFCTL_ERR_NONE);
}


/*
 * sym_matchname() - function to be called on each symbol in a dynsym
 * section. Used to find the name of a symbol whose address is known.
 */
static tnfctl_errcode_t
sym_matchname(char *name, uintptr_t addr, void *sym_entry,
    tnfctl_elf_search_t * search_info_p)
{
    sym_args_t  *symargs_p = (sym_args_t *) search_info_p->record_data;
    Elf3264_Sym *sym = (Elf3264_Sym *) sym_entry;

#ifdef VERYVERBOSE
    (void) fprintf(stderr, "sym_matchname: checking \"%s\"\n", name);
#endif

    if ((sym->st_shndx != SHN_UNDEF) &&
            symargs_p->sa_addr == addr) {

        DBG_TNF_PROBE_2(sym_matchname_1, "libtnfctl",
            "sunw%verbosity 2; sunw%debug '\tMatched Name'",
            tnf_string, symbol_found, name,
            tnf_opaque, address, addr);

        symargs_p->sa_name = strdup(name);
    }

    return (TNFCTL_ERR_NONE);
}