Restored db_elf.c from the Attic. This will be used for a quick fix for

the longstanding brokenness of symbols in ddb at boot time.  It doesn't
compile and is not attached to the build yet.

1 files changed, 381 insertions, 0 deletions

diff --git a/sys/ddb/db_elf.c b/sys/ddb/db_elf.c
new file mode 100644
index 0000000..b4fd53d
--- /dev/null
+++ b/sys/ddb/db_elf.c
@@ -0,0 +1,381 @@
+/* $FreeBSD$ */
+/*	$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