/* $FreeBSD$ */ /* $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. */ #if defined(__ELF__) && defined(__alpha__) #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> #include <machine/elf.h> 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)) 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; const 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; const 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; c_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(void) { if (ksym_end > ksym_start) X_db_sym_init(ksym_start, ksym_end, "kernel"); } #endif