From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265001AbUFVQDn (ORCPT ); Tue, 22 Jun 2004 12:03:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264929AbUFVQBY (ORCPT ); Tue, 22 Jun 2004 12:01:24 -0400 Received: from 41.150.104.212.access.eclipse.net.uk ([212.104.150.41]:54941 "EHLO voidhawk.shadowen.org") by vger.kernel.org with ESMTP id S265009AbUFVP50 (ORCPT ); Tue, 22 Jun 2004 11:57:26 -0400 Date: Tue, 22 Jun 2004 16:57:03 +0100 From: Andy Whitcroft Message-Id: <200406221557.i5MFv3YN020056@voidhawk.shadowen.org> To: linux-kernel@vger.kernel.org Subject: [PATCH] consolidate in kernel configuration Cc: akpm@osdl.org, apw@shadowen.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org It appears that when we enable CONFIG_IKCONFIG and CONFIG_IKCONFIG_PROC that we actually include two different copies of the .config file. One plain text and one compressed. The plain text one used when extracting from the binary is also not recovered cleanly. The patch below removes this duplication using the same compressed version for both purposes. Hopefully this will also make it more reasonable to default this option to on. -apw === 8< ==== Being able to recover the configuration from a kernel is very useful and it would be nice to default this option to Yes. Currently, to have the config available both from the image (using extract-ikconfig) and via /proc we keep two copies of the original .config in the kernel. One in plain text and one gzip compressed. This is not optimal. This patch removes the plain text version of the configuration and updates the extraction tools to locate and use the gzip'd version of the file. This has the added bonus of providing us with the exact same results in both cases, the original .config; including the comments. Signed-off-by: Andy Whitcroft --- diff -X /home/apw/brief/lib/vdiff.excl -rupN reference/kernel/Makefile current/kernel/Makefile --- reference/kernel/Makefile 2004-06-18 23:21:16.000000000 +0100 +++ current/kernel/Makefile 2004-06-22 16:29:29.000000000 +0100 @@ -34,23 +34,7 @@ ifneq ($(CONFIG_IA64),y) CFLAGS_sched.o := $(PROFILING) -fno-omit-frame-pointer endif -# configs.o uses generated files - dependecies must be listed explicitly -$(obj)/configs.o: $(obj)/ikconfig.h - -ifdef CONFIG_IKCONFIG_PROC $(obj)/configs.o: $(obj)/config_data.h -endif - -# ikconfig.h contains all the selected config entries - generated -# from top-level Makefile and .config. Info from ikconfig.h can -# be extracted from the kernel binary. - -quiet_cmd_ikconfig = IKCFG $@ - cmd_ikconfig = $(CONFIG_SHELL) $< .config $(srctree)/Makefile > $@ - -targets += ikconfig.h -$(obj)/ikconfig.h: scripts/mkconfigs .config Makefile FORCE - $(call if_changed,ikconfig) # config_data.h contains the same information as ikconfig.h but gzipped. # Info from config_data can be extracted from /proc/config* @@ -59,7 +43,7 @@ $(obj)/config_data.gz: .config FORCE $(call if_changed,gzip) quiet_cmd_ikconfiggz = IKCFG $@ - cmd_ikconfiggz = cat $< | scripts/bin2c kernel_config_data > $@ + cmd_ikconfiggz = (echo "const char kernel_config_data[] = MAGIC_START"; cat $< | scripts/bin2c; echo "MAGIC_END;") > $@ targets += config_data.h $(obj)/config_data.h: $(obj)/config_data.gz FORCE $(call if_changed,ikconfiggz) diff -X /home/apw/brief/lib/vdiff.excl -rupN reference/kernel/configs.c current/kernel/configs.c --- reference/kernel/configs.c 2004-06-18 19:48:47.000000000 +0100 +++ current/kernel/configs.c 2004-06-22 16:29:29.000000000 +0100 @@ -34,13 +34,26 @@ /**************************************************/ /* the actual current config file */ -/* This one is for extraction from the kernel binary file image. */ -#include "ikconfig.h" +/* + * Define kernel_config_data and kernel_config_data_size, which contains the + * wrapped and compressed configuration file. The file is first compressed + * with gzip and then bounded by two eight byte magic numbers to allow + * extraction from a binary kernel image: + * + * IKCFG_ST + * + * IKCFG_ED + */ +#define MAGIC_START "IKCFG_ST" +#define MAGIC_END "IKCFG_ED" +#include "config_data.h" -#ifdef CONFIG_IKCONFIG_PROC -/* This is the data that can be read from /proc/config.gz. */ -#include "config_data.h" +#define MAGIC_SIZE (sizeof(MAGIC_START) - 1) +#define kernel_config_data_size \ + (sizeof(kernel_config_data) - MAGIC_SIZE * 2) + +#ifdef CONFIG_IKCONFIG_PROC /**************************************************/ /* globals and useful constants */ @@ -58,7 +71,7 @@ ikconfig_read_current(struct file *file, return 0; count = min(len, (size_t)(kernel_config_data_size - pos)); - if(copy_to_user(buf, kernel_config_data + pos, count)) + if (copy_to_user(buf, kernel_config_data + MAGIC_SIZE + pos, count)) return -EFAULT; *offset += count; diff -X /home/apw/brief/lib/vdiff.excl -rupN reference/scripts/extract-ikconfig current/scripts/extract-ikconfig --- reference/scripts/extract-ikconfig 2004-01-09 06:59:45.000000000 +0000 +++ current/scripts/extract-ikconfig 2004-06-22 16:29:29.000000000 +0100 @@ -1,9 +1,31 @@ -#! /bin/bash +#!/bin/sh # extracts .config info from a [b]zImage file # uses: binoffset (new), dd, zcat, strings, grep # $arg1 is [b]zImage filename -TMPFILE="" +binoffset="./scripts/binoffset" + +IKCFG_ST="0x49 0x4b 0x43 0x46 0x47 0x5f 0x53 0x54" +IKCFG_ED="0x49 0x4b 0x43 0x46 0x47 0x5f 0x45 0x44" +function dump_config { + typeset file="$1" + + start=`$binoffset $file $IKCFG_ST 2>/dev/null` + [ "$?" != "0" ] && start="-1" + if [ "$start" -eq "-1" ]; then + return + fi + end=`$binoffset $file $IKCFG_ED 2>/dev/null` + + let start="$start + 8" + let size="$end - $start" + + head --bytes="$end" "$file" | tail --bytes="$size" | zcat + + clean_up + exit 0 +} + usage() { @@ -12,8 +34,7 @@ usage() clean_up() { - if [ -z $ISCOMP ] - then + if [ "$TMPFILE" != "" ]; then rm -f $TMPFILE fi } @@ -21,46 +42,36 @@ clean_up() if [ $# -lt 1 ] then usage - exit + exit 1 fi -image=$1 +TMPFILE="/tmp/ikconfig-$$" +image="$1" -# There are two gzip headers, as well as arches which don't compress their -# kernel. -GZHDR="0x1f 0x8b 0x08 0x00" -if [ `binoffset $image $GZHDR >/dev/null 2>&1 ; echo $?` -ne 0 ] -then - GZHDR="0x1f 0x8b 0x08 0x08" - if [ `binoffset $image $GZHDR >/dev/null 2>&1 ; echo $?` -ne 0 ] - then - ISCOMP=0 - fi -fi +# vmlinux: Attempt to dump the configuration from the file directly +dump_config "$image" -PID=$$ +GZHDR1="0x1f 0x8b 0x08 0x00" +GZHDR2="0x1f 0x8b 0x08 0x08" -# Extract and uncompress the kernel image if necessary -if [ -z $ISCOMP ] -then - TMPFILE="/tmp/`basename $image`.vmlin.$PID" - dd if=$image bs=1 skip=`binoffset $image $GZHDR` 2> /dev/null | zcat > $TMPFILE -else - TMPFILE=$image +# vmlinux.gz: Check for a compressed images +off=`$binoffset "$image" $GZHDR1 2>/dev/null` +[ "$?" != "0" ] && off="-1" +if [ "$off" -eq "-1" ]; then + off=`$binoffset "$image" $GZHDR2 2>/dev/null` + [ "$?" != "0" ] && off="-1" fi - -# Look for strings. -strings $TMPFILE | grep "CONFIG_BEGIN=n" > /dev/null -if [ $? -eq 0 ] -then - strings $TMPFILE | awk "/CONFIG_BEGIN=n/,/CONFIG_END=n/" > $image.oldconfig.$PID -else - echo "ERROR: Unable to extract kernel configuration information." - echo " This kernel image may not have the config info." - clean_up - exit 1 +if [ "$off" -eq "0" ]; then + zcat <"$image" >"$TMPFILE" + dump_config "$TMPFILE" +elif [ "$off" -ne "-1" ]; then + (dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \ + zcat >"$TMPFILE" + dump_config "$TMPFILE" fi -echo "Kernel configuration written to $image.oldconfig.$PID" +echo "ERROR: Unable to extract kernel configuration information." +echo " This kernel image may not have the config info." + clean_up -exit 0 +exit 1