NetBSD/sys/ddb/db_elf.c

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/* $NetBSD: db_elf.c,v 1.2 1997/09/05 21:46:59 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 <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>
#include <ddb/db_extern.h>
#ifdef DB_ELF_SYMBOLS
#ifndef DB_ELFSIZE
#error Must define DB_ELFSIZE!
#endif
#define ELFSIZE DB_ELFSIZE
#include <sys/exec_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))
/*
* 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 (bcmp(elf->e_ident, Elf_e_ident, Elf_e_siz) != 0)
goto badheader;
switch (elf->e_machine) {
ELFDEFNAME(MACHDEP_ID_CASES)
default:
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 *)(symtab + elf->e_shoff);
for (i = 0; i < elf->e_shnum; i++) {
switch (shp[i].sh_type) {
case Elf_sht_strtab:
if (shp[i].sh_size < NBPG) {
shp[i].sh_type = Elf_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 Elf_sht_symtab:
if (symtab_start != NULL)
goto multiple_symtab;
symtab_start = (Elf_Sym *)(symtab + shp[i].sh_offset);
symtab_end = (Elf_Sym *)(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.
*/
if (db_add_symbol_table((char *)symtab_start,
(char *)symtab_end, name, (char *)symtab) != -1)
db_printf("[ preserving %lu bytes of %s symbol table ]\n",
(u_long)roundup((esymtab - symtab), sizeof(u_long)), name);
return;
badheader:
db_printf("[ %s symbol table not valid ]\n", name);
return;
multiple_strtab:
db_printf("[ %s has multiple string tables ]\n", name);
return;
multiple_symtab:
db_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 == Elf_sht_strtab)
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_SYM_TYPE(symp->st_info) != Elf_estt_object &&
ELF_SYM_TYPE(symp->st_info) != Elf_estt_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_SYM_TYPE(symp->st_info) ==
Elf_estt_func &&
ELF_SYM_BIND(symp->st_info) !=
Elf_estb_local)
break;
if (strategy == DB_STGY_ANY &&
ELF_SYM_BIND(symp->st_info) !=
Elf_estb_local)
break;
}
} else if ((off - symp->st_value) == diff) {
if (rsymp == NULL)
rsymp = symp;
else if (ELF_SYM_BIND(rsymp->st_info) ==
Elf_estb_local &&
ELF_SYM_BIND(symp->st_info) !=
Elf_estb_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.
*/
void
ddb_init(sym_start, sym_end)
void *sym_start, *sym_end;
{
if (sym_end > sym_start)
X_db_sym_init(sym_start, sym_end, "netbsd");
}
#endif /* DB_ELF_SYMBOLS */