401 lines
10 KiB
C
401 lines
10 KiB
C
/* $NetBSD: db_elf.c,v 1.7 1998/12/04 20:18:05 thorpej Exp $ */
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/*-
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* Copyright (c) 1997 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <machine/db_machdep.h>
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#include <ddb/db_sym.h>
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#include <ddb/db_output.h>
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#include <ddb/db_extern.h>
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#ifdef DB_ELF_SYMBOLS
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#ifndef DB_ELFSIZE
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#error Must define DB_ELFSIZE!
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#endif
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#define ELFSIZE DB_ELFSIZE
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#include <sys/exec_elf.h>
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#define CONCAT(x,y) __CONCAT(x,y)
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#define ELFDEFNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
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static char *db_elf_find_strtab __P((db_symtab_t *));
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#define STAB_TO_SYMSTART(stab) ((Elf_Sym *)((stab)->start))
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#define STAB_TO_SYMEND(stab) ((Elf_Sym *)((stab)->end))
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#define STAB_TO_EHDR(stab) ((Elf_Ehdr *)((stab)->private))
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#define STAB_TO_SHDR(stab, e) ((Elf_Shdr *)((stab)->private + (e)->e_shoff))
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boolean_t db_elf_sym_init __P((int, void *, void *, const char *));
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db_sym_t db_elf_lookup __P((db_symtab_t *, char *));
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db_sym_t db_elf_search_symbol __P((db_symtab_t *, db_addr_t,
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db_strategy_t, db_expr_t *));
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void db_elf_symbol_values __P((db_symtab_t *, db_sym_t,
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char **, db_expr_t *));
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boolean_t db_elf_line_at_pc __P((db_symtab_t *, db_sym_t,
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char **, int *, db_expr_t));
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boolean_t db_elf_sym_numargs __P((db_symtab_t *, db_sym_t, int *,
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char **));
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db_symformat_t db_symformat_elf = {
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"ELF",
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db_elf_sym_init,
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db_elf_lookup,
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db_elf_search_symbol,
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db_elf_symbol_values,
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db_elf_line_at_pc,
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db_elf_sym_numargs,
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};
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/*
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* Find the symbol table and strings; tell ddb about them.
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*/
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boolean_t
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db_elf_sym_init(symsize, symtab, esymtab, name)
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int symsize; /* size of symbol table */
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void *symtab; /* pointer to start of symbol table */
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void *esymtab; /* pointer to end of string table,
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for checking - rounded up to integer
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boundary */
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const char *name;
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{
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Elf_Ehdr *elf;
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Elf_Shdr *shp;
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Elf_Sym *symp, *symtab_start, *symtab_end;
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char *strtab_start, *strtab_end;
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int i;
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if (ALIGNED_POINTER(symtab, long) == 0) {
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printf("[ %s symbol table has bad start address %p ]\n",
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name, symtab);
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return (FALSE);
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}
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symtab_start = symtab_end = NULL;
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strtab_start = strtab_end = NULL;
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/*
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* The format of the symbols loaded by the boot program is:
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*
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* Elf exec header
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* first section header
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* . . .
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* . . .
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* last section header
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* first symbol or string table section
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* . . .
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* . . .
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* last symbol or string table section
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*/
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/*
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* Validate the Elf header.
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*/
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elf = (Elf_Ehdr *)symtab;
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if (memcmp(elf->e_ident, Elf_e_ident, Elf_e_siz) != 0)
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goto badheader;
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switch (elf->e_machine) {
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ELFDEFNAME(MACHDEP_ID_CASES)
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default:
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goto badheader;
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}
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/*
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* We need to avoid the section header string table (small string
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* table which names the sections). We do this by assuming that
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* the following two conditions will be true:
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*
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* (1) .shstrtab will be smaller than one page.
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* (2) .strtab will be larger than one page.
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*
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* When we encounter what we think is the .shstrtab, we change
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* its section type Elf_sht_null so that it will be ignored
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* later.
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*/
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shp = (Elf_Shdr *)(symtab + elf->e_shoff);
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for (i = 0; i < elf->e_shnum; i++) {
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switch (shp[i].sh_type) {
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case Elf_sht_strtab:
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if (shp[i].sh_size < NBPG) {
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shp[i].sh_type = Elf_sht_null;
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continue;
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}
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if (strtab_start != NULL)
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goto multiple_strtab;
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strtab_start = (char *)(symtab + shp[i].sh_offset);
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strtab_end = (char *)(symtab + shp[i].sh_offset +
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shp[i].sh_size);
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break;
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case Elf_sht_symtab:
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if (symtab_start != NULL)
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goto multiple_symtab;
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symtab_start = (Elf_Sym *)(symtab + shp[i].sh_offset);
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symtab_end = (Elf_Sym *)(symtab + shp[i].sh_offset +
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shp[i].sh_size);
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break;
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default:
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/* Ignore all other sections. */
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break;
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}
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}
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/*
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* Now, sanity check the symbols against the string table.
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*/
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if (symtab_start == NULL || strtab_start == NULL ||
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ALIGNED_POINTER(symtab_start, long) == 0 ||
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ALIGNED_POINTER(strtab_start, long) == 0)
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goto badheader;
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for (symp = symtab_start; symp < symtab_end; symp++)
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if (symp->st_name + strtab_start > strtab_end)
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goto badheader;
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/*
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* Link the symbol table into the debugger.
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*/
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if (db_add_symbol_table((char *)symtab_start,
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(char *)symtab_end, name, (char *)symtab) != -1) {
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printf("[ preserving %lu bytes of %s ELF symbol table ]\n",
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(u_long)roundup((esymtab - symtab), sizeof(u_long)), name);
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return (TRUE);
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}
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return (FALSE);
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badheader:
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printf("[ %s ELF symbol table not valid ]\n", name);
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return (FALSE);
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multiple_strtab:
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printf("[ %s has multiple ELF string tables ]\n", name);
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return (FALSE);
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multiple_symtab:
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printf("[ %s has multiple ELF symbol tables ]\n", name);
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return (FALSE);
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}
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/*
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* Internal helper function - return a pointer to the string table
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* for the current symbol table.
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*/
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static char *
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db_elf_find_strtab(stab)
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db_symtab_t *stab;
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{
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Elf_Ehdr *elf = STAB_TO_EHDR(stab);
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Elf_Shdr *shp = STAB_TO_SHDR(stab, elf);
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int i;
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for (i = 0; i < elf->e_shnum; i++) {
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if (shp[i].sh_type == Elf_sht_strtab)
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return (stab->private + shp[i].sh_offset);
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}
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return (NULL);
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}
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/*
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* Lookup the symbol with the given name.
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*/
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db_sym_t
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db_elf_lookup(stab, symstr)
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db_symtab_t *stab;
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char *symstr;
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{
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Elf_Sym *symp, *symtab_start, *symtab_end;
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char *strtab;
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symtab_start = STAB_TO_SYMSTART(stab);
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symtab_end = STAB_TO_SYMEND(stab);
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strtab = db_elf_find_strtab(stab);
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if (strtab == NULL)
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return ((db_sym_t)0);
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for (symp = symtab_start; symp < symtab_end; symp++) {
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if (symp->st_name != 0 &&
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db_eqname(strtab + symp->st_name, symstr, 0))
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return ((db_sym_t)symp);
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}
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return ((db_sym_t)0);
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}
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/*
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* Search for the symbol with the given address (matching within the
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* provided threshold).
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*/
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db_sym_t
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db_elf_search_symbol(symtab, off, strategy, diffp)
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db_symtab_t *symtab;
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db_addr_t off;
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db_strategy_t strategy;
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db_expr_t *diffp; /* in/out */
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{
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Elf_Sym *rsymp, *symp, *symtab_start, *symtab_end;
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db_expr_t diff = *diffp;
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symtab_start = STAB_TO_SYMSTART(symtab);
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symtab_end = STAB_TO_SYMEND(symtab);
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rsymp = NULL;
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for (symp = symtab_start; symp < symtab_end; symp++) {
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if (symp->st_name == 0)
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continue;
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#if 0
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/* This prevents me from seeing anythin in locore.s -- eeh */
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if (ELF_SYM_TYPE(symp->st_info) != Elf_estt_object &&
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ELF_SYM_TYPE(symp->st_info) != Elf_estt_func)
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continue;
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#endif
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if (off >= symp->st_value) {
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if ((off - symp->st_value) < diff) {
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diff = off - symp->st_value;
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rsymp = symp;
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if (diff == 0) {
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if (strategy == DB_STGY_PROC &&
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ELF_SYM_TYPE(symp->st_info) ==
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Elf_estt_func &&
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ELF_SYM_BIND(symp->st_info) !=
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Elf_estb_local)
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break;
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if (strategy == DB_STGY_ANY &&
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ELF_SYM_BIND(symp->st_info) !=
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Elf_estb_local)
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break;
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}
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} else if ((off - symp->st_value) == diff) {
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if (rsymp == NULL)
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rsymp = symp;
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else if (ELF_SYM_BIND(rsymp->st_info) ==
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Elf_estb_local &&
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ELF_SYM_BIND(symp->st_info) !=
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Elf_estb_local) {
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/* pick the external symbol */
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rsymp = symp;
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}
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}
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}
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}
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if (rsymp == NULL)
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*diffp = off;
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else
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*diffp = diff;
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return ((db_sym_t)rsymp);
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}
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/*
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* Return the name and value for a symbol.
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*/
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void
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db_elf_symbol_values(symtab, sym, namep, valuep)
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db_symtab_t *symtab;
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db_sym_t sym;
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char **namep;
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db_expr_t *valuep;
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{
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Elf_Sym *symp = (Elf_Sym *)sym;
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char *strtab;
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if (namep) {
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strtab = db_elf_find_strtab(symtab);
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if (strtab == NULL)
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*namep = NULL;
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else
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*namep = strtab + symp->st_name;
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}
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if (valuep)
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*valuep = symp->st_value;
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}
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/*
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* Return the file and line number of the current program counter
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* if we can find the appropriate debugging symbol.
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*/
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boolean_t
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db_elf_line_at_pc(symtab, cursym, filename, linenum, off)
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db_symtab_t *symtab;
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db_sym_t cursym;
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char **filename;
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int *linenum;
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db_expr_t off;
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{
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/*
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* XXX We don't support this (yet).
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*/
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return (FALSE);
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}
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/*
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* Returns the number of arguments to a function and their
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* names if we can find the appropriate debugging symbol.
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*/
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boolean_t
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db_elf_sym_numargs(symtab, cursym, nargp, argnamep)
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db_symtab_t *symtab;
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db_sym_t cursym;
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int *nargp;
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char **argnamep;
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{
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/*
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* XXX We don't support this (yet).
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*/
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return (FALSE);
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}
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#endif /* DB_ELF_SYMBOLS */
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