Add DDB symbol support for ELF and KLD. The KLD support only supports global

symbols so its not too useful.  Changes to the kernel linker to allow it to
supply DDB with symbols will come later.
This commit is contained in:
dfr 1998-06-28 00:57:28 +00:00
parent 0cc7230297
commit f0112afdb9
2 changed files with 539 additions and 0 deletions

402
sys/ddb/db_elf.c Normal file
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/* $Id$ */
/* $NetBSD: db_elf.c,v 1.4 1998/05/03 18:49:54 thorpej Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "opt_ddb.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <machine/db_machdep.h>
#include <ddb/db_sym.h>
#include <ddb/db_output.h>
#ifdef DB_ELF_SYMBOLS
#ifndef DB_ELFSIZE
#error Must define DB_ELFSIZE!
#endif
#define ELFSIZE DB_ELFSIZE
#include <machine/elf.h>
#define CONCAT(x,y) __CONCAT(x,y)
#define ELFDEFNAME(x) CONCAT(Elf,CONCAT(ELFSIZE,CONCAT(_,x)))
static char *db_elf_find_strtab __P((db_symtab_t *));
#define STAB_TO_SYMSTART(stab) ((Elf_Sym *)((stab)->start))
#define STAB_TO_SYMEND(stab) ((Elf_Sym *)((stab)->end))
#define STAB_TO_EHDR(stab) ((Elf_Ehdr *)((stab)->private))
#define STAB_TO_SHDR(stab, e) ((Elf_Shdr *)((stab)->private + (e)->e_shoff))
#define Elf_Ehdr ELFDEFNAME(Ehdr)
#define Elf_Shdr ELFDEFNAME(Shdr)
#define Elf_Sym ELFDEFNAME(Sym)
#if ELFSIZE == 64
#define ELF_ST_TYPE(x) ELF64_ST_TYPE(x)
#define ELF_ST_BIND(x) ELF64_ST_BIND(x)
#else
#define ELF_ST_TYPE(x) ELF32_ST_TYPE(x)
#define ELF_ST_BIND(x) ELF32_ST_BIND(x)
#endif
void X_db_sym_init(void *symtab, void *esymtab, char *name);
/*
* Find the symbol table and strings; tell ddb about them.
*/
void
X_db_sym_init(symtab, esymtab, name)
void *symtab; /* pointer to start of symbol table */
void *esymtab; /* pointer to end of string table,
for checking - rounded up to integer
boundary */
char *name;
{
Elf_Ehdr *elf;
Elf_Shdr *shp;
Elf_Sym *symp, *symtab_start, *symtab_end;
char *strtab_start, *strtab_end;
int i;
if (ALIGNED_POINTER(symtab, long) == 0) {
printf("DDB: bad symbol table start address %p\n", symtab);
return;
}
symtab_start = symtab_end = NULL;
strtab_start = strtab_end = NULL;
/*
* The format of the symbols loaded by the boot program is:
*
* Elf exec header
* first section header
* . . .
* . . .
* last section header
* first symbol or string table section
* . . .
* . . .
* last symbol or string table section
*/
/*
* Validate the Elf header.
*/
elf = (Elf_Ehdr *)symtab;
if (elf->e_ident[EI_MAG0] != ELFMAG0
|| elf->e_ident[EI_MAG1] != ELFMAG1
|| elf->e_ident[EI_MAG2] != ELFMAG2
|| elf->e_ident[EI_MAG3] != ELFMAG3)
goto badheader;
if (!ELF_MACHINE_OK(elf->e_machine))
goto badheader;
/*
* We need to avoid the section header string table (small string
* table which names the sections). We do this by assuming that
* the following two conditions will be true:
*
* (1) .shstrtab will be smaller than one page.
* (2) .strtab will be larger than one page.
*
* When we encounter what we think is the .shstrtab, we change
* its section type Elf_sht_null so that it will be ignored
* later.
*/
shp = (Elf_Shdr *)((char*)symtab + elf->e_shoff);
for (i = 0; i < elf->e_shnum; i++) {
if (shp[i].sh_addr || i == elf->e_shstrndx)
continue;
switch (shp[i].sh_type) {
case SHT_STRTAB:
if (shp[i].sh_size < PAGE_SIZE) {
shp[i].sh_type = SHT_NULL;
continue;
}
if (strtab_start != NULL)
goto multiple_strtab;
strtab_start = (char *)symtab + shp[i].sh_offset;
strtab_end = (char *)symtab + shp[i].sh_offset +
shp[i].sh_size;
break;
case SHT_SYMTAB:
if (symtab_start != NULL)
goto multiple_symtab;
symtab_start = (Elf_Sym *)((char*)symtab + shp[i].sh_offset);
symtab_end = (Elf_Sym *)((char*)symtab + shp[i].sh_offset +
shp[i].sh_size);
break;
default:
/* Ignore all other sections. */
break;
}
}
/*
* Now, sanity check the symbols against the string table.
*/
if (symtab_start == NULL || strtab_start == NULL ||
ALIGNED_POINTER(symtab_start, long) == 0 ||
ALIGNED_POINTER(strtab_start, long) == 0)
goto badheader;
for (symp = symtab_start; symp < symtab_end; symp++)
if (symp->st_name + strtab_start > strtab_end)
goto badheader;
/*
* Link the symbol table into the debugger.
*/
db_add_symbol_table((char *)symtab_start,
(char *)symtab_end, name, (char *)symtab);
printf("[ preserving %lu bytes of %s symbol table ]\n",
(u_long)roundup(((char*)esymtab - (char*)symtab), sizeof(u_long)), name);
return;
badheader:
printf("[ %s symbol table not valid ]\n", name);
return;
multiple_strtab:
printf("[ %s has multiple string tables ]\n", name);
return;
multiple_symtab:
printf("[ %s has multiple symbol tables ]\n", name);
return;
}
/*
* Internal helper function - return a pointer to the string table
* for the current symbol table.
*/
static char *
db_elf_find_strtab(stab)
db_symtab_t *stab;
{
Elf_Ehdr *elf = STAB_TO_EHDR(stab);
Elf_Shdr *shp = STAB_TO_SHDR(stab, elf);
int i;
for (i = 0; i < elf->e_shnum; i++) {
if (shp[i].sh_type == SHT_STRTAB
&& !shp[i].sh_addr && i != elf->e_shstrndx)
return (stab->private + shp[i].sh_offset);
}
return (NULL);
}
/*
* Lookup the symbol with the given name.
*/
db_sym_t
X_db_lookup(stab, symstr)
db_symtab_t *stab;
char *symstr;
{
Elf_Sym *symp, *symtab_start, *symtab_end;
char *strtab;
symtab_start = STAB_TO_SYMSTART(stab);
symtab_end = STAB_TO_SYMEND(stab);
strtab = db_elf_find_strtab(stab);
if (strtab == NULL)
return ((db_sym_t)0);
for (symp = symtab_start; symp < symtab_end; symp++) {
if (symp->st_name != 0 &&
db_eqname(strtab + symp->st_name, symstr, 0))
return ((db_sym_t)symp);
}
return ((db_sym_t)0);
}
/*
* Search for the symbol with the given address (matching within the
* provided threshold).
*/
db_sym_t
X_db_search_symbol(symtab, off, strategy, diffp)
db_symtab_t *symtab;
db_addr_t off;
db_strategy_t strategy;
db_expr_t *diffp; /* in/out */
{
Elf_Sym *rsymp, *symp, *symtab_start, *symtab_end;
db_expr_t diff = *diffp;
symtab_start = STAB_TO_SYMSTART(symtab);
symtab_end = STAB_TO_SYMEND(symtab);
rsymp = NULL;
for (symp = symtab_start; symp < symtab_end; symp++) {
if (symp->st_name == 0)
continue;
if (ELF_ST_TYPE(symp->st_info) != STT_OBJECT &&
ELF_ST_TYPE(symp->st_info) != STT_FUNC)
continue;
if (off >= symp->st_value) {
if ((off - symp->st_value) < diff) {
diff = off - symp->st_value;
rsymp = symp;
if (diff == 0) {
if (strategy == DB_STGY_PROC &&
ELF_ST_TYPE(symp->st_info) ==
STT_FUNC &&
ELF_ST_BIND(symp->st_info) !=
STB_LOCAL)
break;
if (strategy == DB_STGY_ANY &&
ELF_ST_BIND(symp->st_info) !=
STB_LOCAL)
break;
}
} else if ((off - symp->st_value) == diff) {
if (rsymp == NULL)
rsymp = symp;
else if (ELF_ST_BIND(rsymp->st_info) ==
STB_LOCAL &&
ELF_ST_BIND(symp->st_info) !=
STB_LOCAL) {
/* pick the external symbol */
rsymp = symp;
}
}
}
}
if (rsymp == NULL)
*diffp = off;
else
*diffp = diff;
return ((db_sym_t)rsymp);
}
/*
* Return the name and value for a symbol.
*/
void
X_db_symbol_values(symtab, sym, namep, valuep)
db_symtab_t *symtab;
db_sym_t sym;
char **namep;
db_expr_t *valuep;
{
Elf_Sym *symp = (Elf_Sym *)sym;
char *strtab;
if (namep) {
strtab = db_elf_find_strtab(symtab);
if (strtab == NULL)
*namep = NULL;
else
*namep = strtab + symp->st_name;
}
if (valuep)
*valuep = symp->st_value;
}
/*
* Return the file and line number of the current program counter
* if we can find the appropriate debugging symbol.
*/
boolean_t
X_db_line_at_pc(symtab, cursym, filename, linenum, off)
db_symtab_t *symtab;
db_sym_t cursym;
char **filename;
int *linenum;
db_expr_t off;
{
/*
* XXX We don't support this (yet).
*/
return (FALSE);
}
/*
* Returns the number of arguments to a function and their
* names if we can find the appropriate debugging symbol.
*/
boolean_t
X_db_sym_numargs(symtab, cursym, nargp, argnamep)
db_symtab_t *symtab;
db_sym_t cursym;
int *nargp;
char **argnamep;
{
/*
* XXX We don't support this (yet).
*/
return (FALSE);
}
/*
* Initialization routine for Elf files.
*/
extern void *ksym_start, *ksym_end;
void
kdb_init()
{
if (ksym_end > ksym_start)
X_db_sym_init(ksym_start, ksym_end, "kernel");
}
#endif /* DB_ELF_SYMBOLS */

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/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id$
* from db_aout.c,v 1.20 1998/06/07 17:09:36 dfr Exp
*/
/*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
/*
* Symbol table routines for a.out format files.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/linker.h>
#include <machine/bootinfo.h>
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
extern linker_file_t linker_kernel_file;
#define KF linker_kernel_file
db_sym_t
X_db_lookup(stab, symstr)
db_symtab_t *stab;
char * symstr;
{
linker_sym_t sym;
if (!KF)
return 0;
if (KF->ops->lookup_symbol(KF, symstr, &sym) == 0)
return (db_sym_t) sym;
else
return (db_sym_t) 0;
}
db_sym_t
X_db_search_symbol(symtab, off, strategy, diffp)
db_symtab_t * symtab;
register
db_addr_t off;
db_strategy_t strategy;
db_expr_t *diffp; /* in/out */
{
linker_sym_t sym;
long diff;
if (!KF)
return 0;
if (KF->ops->search_symbol(KF, (caddr_t) off, &sym, &diff) == 0) {
*diffp = (db_expr_t) diff;
return (db_sym_t) sym;
}
return 0;
}
/*
* Return the name and value for a symbol.
*/
void
X_db_symbol_values(dbsym, namep, valuep)
db_sym_t dbsym;
char **namep;
db_expr_t *valuep;
{
linker_sym_t sym = (linker_sym_t) dbsym;
linker_symval_t symval;
KF->ops->symbol_values(KF, sym, &symval);
if (namep)
*namep = (char*) symval.name;
if (valuep)
*valuep = (db_expr_t) symval.value;
}
boolean_t
X_db_line_at_pc(symtab, cursym, filename, linenum, off)
db_symtab_t * symtab;
db_sym_t cursym;
char **filename;
int *linenum;
db_expr_t off;
{
return FALSE;
}
boolean_t
X_db_sym_numargs(symtab, cursym, nargp, argnamep)
db_symtab_t * symtab;
db_sym_t cursym;
int *nargp;
char **argnamep;
{
return FALSE;
}
/*
* Initialization routine for a.out files.
*/
void
kdb_init()
{
db_add_symbol_table(0, 0, "kernel", 0);
}