base之modules

因为想知道poky的base版本在启动阶段加载了哪些驱动模块，所以花时间研究了一下。

1.通过ipkg管理系统查阅信息(以rfcomm.ko为例):

"/usr/lib/ipkg/info/kernel-module-rfcomm.control"

Package: kernel-module-rfcommVersion: 2.6.22.5-moko11+svnr3238-r15Description: rfcomm kernel module; Bluetooth RFCOMM ver 1.8Section: kernelPriority: optionalMaintainer: OpenedHand <[e-mail]>Architecture: fic-gta01OE: linux-openmokoHomepage: unknownDepends: update-modules, kernel-2.6.22.5-moko11, kernel-module-l2cap, kernel-module-bluetoothSource: http://kernel.org//pub/linux/kernel/v2.6/linux-2.6.22.tar.bz2 http://kernel.org//pub/linux/kernel/v2.6/patch-2.6.22.5.bz2;patch=1 svn://svn.openmoko.org/branches/src/target/kernel/2.6.22.x;module=patches;proto=http file://fix-EVIOCGRAB-semantics-2.6.22.5.patch;patch=1 file://fix-gta01-flowcontrol2-2.6.22.5.patch;patch=1 file://gta-vibro-pwm-suspend.patch;patch=1 file://tweak_power_button.patch;patch=1 file://break_suspend_cycle.patch;patch=1 http://www.rpsys.net/openzaurus/patches/archive/input_power-r9.patch;patch=1 file://defconfig-2.6.22.5

"/usr/lib/ipkg/info/kernel-module-rfcomm.list"

/etc/modutils/rfcomm/etc/modprobe.d/rfcomm.conf/lib/modules/2.6.22.5-moko11/kernel/net/bluetooth/rfcomm/rfcomm.ko

"/usr/lib/ipkg/info/kernel-module-rfcomm.postinst"

#!/bin/shif [ -n "$D" ]; thenarm-poky-linux-gnueabi-depmod-2.6 -A -b $D -F /home/nebsp/pinky-3.1.1/build/tmp/staging/fic-gta01-poky-linux-gnueabi/kernel/System.map-2.6.22.5-moko11 2.6.22.5-moko11elsedepmod -aupdate-modules || truefiif [ x"$D" = "x" ]; thenmodprobe rfcomm || truefi

"/usr/lib/ipkg/info/kernel-module-rfcomm.postrm"

#!/bin/shupdate-modules || true

 

从"status"文件中查阅到:

Package: kernel-module-rfcommVersion: 2.6.22.5-moko11+svnr3238-r15Depends: update-modules, kernel-2.6.22.5-moko11, kernel-module-l2cap, kernel-module-bluetoothStatus: install ok installedArchitecture: fic-gta01

status为"install ok installed"说明postinst执行成功，通过"build/tmp/cross/bin/arm-poky-linux-gnueabi-depmod-2.6"在/lib/modules/`uname -r`下建立了相关的dep及map信息。

 

2.关于update-modules

它是"/usr/sbin"下一可执行脚本程序

#!/bin/sh## This is the update-modules script for Debian GNU/Linux.# Copyright 1998-2001 Wichert Akkerman <[e-mail]># Licensed under the GNU GPL, version 2#MODCONFFILE=/etc/modules.confMODCONFTMPFILE="${MODCONFFILE}.$$"MODULESFILE=/etc/modulesMODULESTMPFILE="${MODULESFILE}.$$"ARCHDIR=/etc/modutils/archCPUDIR=/etc/modutils/cpuHEADER="### This file is automatically generated by update-modules"set -eif [ "$1" = "force" ] ; thenforce=1elseforce=fi# Reset the sorting order since we depend on itLC_COLLATE=Cexport LC_COLLATEdepdir(){dep=`grep '[[:space:]]*depfile' "${MODCONFFILE}" | tail -n 1 | sed -e 's/depfile=//' -e 's,/[^/]*$,,'`if [ -z "$dep" ] ; thendep="/lib/modules/`uname -r`"fiecho $dep}arch() {local model=`uname -m`case $model ini[0-9]86) model=i386; ;;sun4u) model=sparc64; ;;arm*) model=arm; ;;ppc) model=powerpc; ;;esacecho $model}archmodel() {local arch=`arch`local model=""if [ $arch = "m68k" ]; thenif [ -f /proc/hardware ]; thenmodel=`sed -ne 's/^Model:[[:space:]]*//p' /proc/hardware`case $model inAtari*) model="atari"; ;;Amiga*) model="amiga"; ;;Macintosh*) model="mac"; ;;Motorola*) model="MVME"; ;;*) model="generic"; ;;esacmodel=".${model}"elseecho "/proc/hardware does not exist, assuming general m68k system"model=".generic"fielif [ $arch = "powerpc" ]; thenif [ -f /proc/cpuinfo ]; thenmodel=`sed -ne 's/^machine[[:space:]]*:[[:space:]]*//p' /proc/cpuinfo`case $model inAmiga*) model="apus"; ;;Power*) model="pmac"; ;;*) model="generic"; ;;esacmodel=".${model}"elseecho "/proc/cpuinfo does not exist, assuming general powerpc system"model=".generic"fifiecho "${arch}${model}"}checkoverwrite() {local cfgfile="$1"if [ -f "$cfgfile" ]; thenif ! sed -ne 1p "$cfgfile" | grep -q "^$HEADER" ; thenecho "Error: the current $cfgfile is not automatically generated." >&2if [ -z "$force" ]; thenecho "Use /"update-modules force/" to force (re)generation."exit 1elseecho "force specified, (re)generating file anyway."fififi}createfile() {cat <<EOF > "$1"$HEADER"## Please do not edit this file directly. If you want to change or add# anything please take a look at the files in /etc/modutils and read# the manpage for update-modules.#EOF}addfile() {local src="$1"local tgt="$2"echo "### update-modules: start processing $src" >> "$tgt"if [ -x "$src" ]; thenif ! "$src" >> "$tgt" ; thenecho "Error while executing $src, aborting" >&2exit 1fielsecat "$src" >> "$tgt"ficat <<EOF >> "$tgt"### update-modules: end processing $cfgEOF}checkoverwrite "$MODCONFFILE"if [ 0 -ne "`id -u`" ]; thenecho "You have to be root to do this." >&2exit 2fimodel=`archmodel`oldmodel=$modelwhile [ ! -f "${ARCHDIR}/${model}" ]; dooldmodel=$modelmodel=`echo $oldmodel | sed -e 's//.[^.]/+//'`if [ "$model" = "$oldmodel" ]; thenbreakfiecho "Configuration for $oldmodel not found, trying $model"doneCONF="${ARCHDIR}/${model}"if [ ! -f "$CONF" ]; then## echo "Architecture-specific modutils configuration not found, using defaults"CONF="${ARCHDIR}/generic"fi[ -e "$MODCONFFILE" ] && cp -f "$MODCONFFILE" "${MODCONFFILE}.old"createfile "$MODCONFTMPFILE"createfile "$MODULESTMPFILE"for cfg in /etc/modutils/* $CONF ; doif [ -f "$cfg" ]; then # this check is necesarry to skip /etc/modutils/archsif echo $cfg | grep -q '/.dpkg-[a-z]*/|~$' ; then trueelif echo $cfg | grep -q '/.conf$' ; thenaddfile "$cfg" "$MODCONFTMPFILE"elseaddfile "$cfg" "$MODULESTMPFILE"fifidonefirst_time=0if [ ! -f $MODULESFILE ]; then first_time=1fimv "$MODCONFTMPFILE" "$MODCONFFILE"mv "$MODULESTMPFILE" "$MODULESFILE"if [ $first_time -eq 1 ]; then /etc/init.d/modutils.sh || truefi# We also call depmod here to stop insmod from complaining that modules.conf# is more recent then modules.dep#if [ -d "`depdir`" -a -f /proc/modules ]thendepmod -A || truefiexit 0

主要完成的工作就是把"/etc/modutils"目录下的"*.conf"文件的内容集中到"/etc/modules.conf"，把其他文件的内容集中到"/etc/modules"。

 

系统在启动阶段会调用"/etc/rcS.d/S20modutils.sh"

#!/bin/shLOAD_MODULE=modprobe[ -f /proc/modules ] || exit 0[ -f /etc/modules ] || exit 0[ -e /sbin/modprobe ] || LOAD_MODULE=insmodif [ ! -e /sbin/depmod ]; then[ -f /lib/modules/`uname -r`/modules.dep ] || LOAD_MODULE=insmodelse [ "$VERBOSE" != no ] && echo "Calculating module dependencies ..."depmod -Aefi[ "$VERBOSE" != no ] && echo -n "Loading modules: "(cat /etc/modules; echo; ) |while read module argsdocase "$module" in/#*|"") continue ;;esac[ "$VERBOSE" != no ] && echo -n "$module "eval "$LOAD_MODULE $module $args >/dev/null 2>&1"done[ "$VERBOSE" != no ] && echoexit 0

即根据"/etc/modules"中的内容自动加载驱动模块。可见通过update-modules工具可以实现模块在启动阶段的自动加载，当然了事前还必须在"/etc/modutils"目录下放置相应文件，譬如"/etc/modutils/rfcomm"。

 

3.关于rootfs在板上第一次启动的初始化问题

poky环境下构建出来的rootfs在板上第一次启动，调用到"/etc/rcS.d/S20modutils.sh"时，"/etc/modules"还不存在，因此那些在构建时被指定为自动加载模式的驱动模块在这个时候失去了正常的加载机会，怎么办???(惊恐ing)。

呵呵，update-modules中有一段代码需要在这时补充说明一下:

first_time=0if [ ! -f $MODULESFILE ]; then first_time=1fiif [ $first_time -eq 1 ]; then /etc/init.d/modutils.sh || truefi

这里的"first_time"用来定义构建出来的rootfs第一次在板子上启动的时刻，因为"/etc/modules"必定会在第一次启动时创建出来，而之后的每次启动，"/etc/modules"都是已经存在的了，"first_time"必不为"1"。这段代码就是专为第一次启动的初始化问题设计的。但是系统如何保证在第一次启动的时候必定会调用到update-modules呢? 这个是由update-modules这个软件包本身来提供支持的。

"/usr/lib/ipkg/info/update-modules.postinst"

if [ "x$D" != "x" ]; thenexit 1fiupdate-modules

再看"status"文件中的信息

Package: update-modulesVersion: 1.0-r6Depends: module-init-tools-depmodStatus: install ok unpackedArchitecture: all

显然系统在执行到"/etc/rcS.d/S98configure"时就会调用update-modules。一切尽在不言中。。。

 

4.关于"/etc/modutils"和"/etc/modprobe.d"

"/meta/packages/linux/linux-openmoko_2.6.22.5.bb"中定义了一些变量

################################################################ module configs specific to this kernel## usbmodule_autoload_ohci-hcd = "ohci-hcd"module_autoload_hci_usb = "hci_usb"module_autoload_g_ether = "g_ether"# audiomodule_autoload_snd-soc-neo1973-wm8753 = "snd-soc-neo1973-wm8753"module_autoload_snd-soc-neo1973-gta02-wm8753 = "snd-soc-neo1973-gta02-wm8753"module_autoload_snd-pcm-oss = "snd-pcm-oss"module_autoload_snd-mixer-oss = "snd-mixer-oss"# sd/mmcmodule_autoload_s3cmci = "s3cmci"

"/meta/classes/kernel.bbclass"中也定义了一些变量

# autoload defaults (alphabetically sorted)module_autoload_hidp = "hidp"module_autoload_ipv6 = "ipv6"module_autoload_ipsec = "ipsec"module_autoload_ircomm-tty = "ircomm-tty"module_autoload_rfcomm = "rfcomm"module_autoload_sa1100-rtc = "sa1100-rtc"# alias defaults (alphabetically sorted)module_conf_af_packet = "alias net-pf-17 af_packet"module_conf_bluez = "alias net-pf-31 bluez"module_conf_bnep = "alias bt-proto-4 bnep"module_conf_hci_uart = "alias tty-ldisc-15 hci_uart"module_conf_l2cap = "alias bt-proto-0 l2cap"module_conf_sco = "alias bt-proto-2 sco"module_conf_rfcomm = "alias bt-proto-3 rfcomm"

"module_autoload_*"表示为这些模块提供自动加载功能。

"module_conf_*"表示为这些模块提供配置文件。

# If autoloading is requested, output /etc/modutils/<name> and append# appropriate modprobe commands to the postinstautoload = bb.data.getVar('module_autoload_%s' % basename, d, 1)if autoload:name = '%s/etc/modutils/%s' % (dvar, basename)f = open(name, 'w')for m in autoload.split():f.write('%s/n' % m)f.close()postinst = bb.data.getVar('pkg_postinst_%s' % pkg, d, 1)if not postinst:bb.fatal("pkg_postinst_%s not defined" % pkg)postinst += bb.data.getVar('autoload_postinst_fragment', d, 1) % autoloadbb.data.setVar('pkg_postinst_%s' % pkg, postinst, d)# Write out any modconf fragmentmodconf = bb.data.getVar('module_conf_%s' % basename, d, 1)if modconf:if bb.data.getVar("KERNEL_MAJOR_VERSION", d, 1) == "2.6":name = '%s/etc/modprobe.d/%s.conf' % (dvar, basename)else:name = '%s/etc/modutils/%s.conf' % (dvar, basename)f = open(name, 'w')f.write("%s/n" % modconf)f.close()

对于autoload:在"/etc/modutils"目录下创建相应文件并构造"postinst"。

对于modconf:如果内核主版本为2.6，则在"/etc/modprobe.d"下创建".conf"文件；否则在"/etc/modutils"下创建".conf"文件。原因在分析"module-init-tools-3.2.2"软件包的"modprobe.c"源码后可知:

dirname = NOFAIL(malloc(strlen(buf.release) + sizeof(MODULE_DIR) + 1));sprintf(dirname, "%s/%s", MODULE_DIR, buf.release);aliasfilename = NOFAIL(malloc(strlen(dirname) + sizeof("/modules.alias")));sprintf(aliasfilename, "%s/modules.alias", dirname);symfilename = NOFAIL(malloc(strlen(dirname) + sizeof("/modules.symbols")));sprintf(symfilename, "%s/modules.symbols", dirname);

modprobe参考了"/lib/modules"目录下的"modules.alias"、"modules.symbols"。

static void read_depends(const char *dirname, const char *start_name, struct list_head *list){char *modules_dep_name;char *line;FILE *modules_dep;int done = 0;asprintf(&modules_dep_name, "%s/%s", dirname, "modules.dep");modules_dep = fopen(modules_dep_name, "r");if (!modules_dep)fatal("Could not load %s: %s/n", modules_dep_name, strerror(errno));/* Stop at first line, as we can have duplicates (eg. symlinks from boot/ */while (!done && (line = getline_wrapped(modules_dep, NULL)) != NULL) {done = add_modules_dep_line(line, start_name, list);free(line);}fclose(modules_dep);free(modules_dep_name);}

modprobe参考了"/lib/modules"目录下的"modules.dep"。

/* Simple format, ignore lines starting with #, one command per line. Returns true or false. */static int read_config(const char *filename, const char *name, int dump_only, int removing, struct module_options **options, struct module_command **commands, struct module_alias **aliases, struct module_blacklist **blacklist){DIR *dir;int ret = 0;/* ignore everything in this directory */if (streq(filename, "/etc/modprobe.d/arch"))return 1;/* Reiser4 has file/directory duality: treat it as both. */dir = opendir(filename);if (dir) {struct dirent *i;while ((i = readdir(dir)) != NULL) {if (!streq(i->d_name,".") && !streq(i->d_name,"..")) {char sub[strlen(filename) + 1 + strlen(i->d_name) + 1];sprintf(sub, "%s/%s", filename, i->d_name);if (!read_config(sub, name, dump_only, removing, options, commands, aliases, blacklist))warn("Failed to open" " config file %s: %s/n", sub, strerror(errno));}}closedir(dir);ret = 1;}if (read_config_file(filename, name, dump_only, removing, options, commands, aliases, blacklist))ret = 1;return ret;}static const char *default_configs[] = {"/etc/modprobe.conf","/etc/modprobe.d",};static void read_toplevel_config(const char *filename, const char *name, int dump_only, int removing, struct module_options **options, struct module_command **commands, struct module_alias **aliases, struct module_blacklist **blacklist){unsigned int i;if (filename) {if (!read_config(filename, name, dump_only, removing, options, commands, aliases, blacklist))fatal("Failed to open config file %s: %s/n", filename, strerror(errno));return;}/* Try defaults. */for (i = 0; i < ARRAY_SIZE(default_configs); i++) {if (read_config(default_configs[i], name, dump_only, removing,options, commands, aliases, blacklist))return;}}

modprobe参考了"/etc/modprobe.conf"文件及"/etc/modprobe.d"目录。