其他分享
首页 > 其他分享> > openwrt/scripts/kconfig.pl 理解

openwrt/scripts/kconfig.pl 理解

作者:互联网

openwrt/scripts/kconfig.pl 理解

目的

理解 openwrt/scripts/kconfig.pl ,了解.config 的生成

开始

一般的编译内核

.config 是由 make xxx_defconfig 生成的

在OpenWrt 中则更复杂些

涉及的文件有

需要理清上述文件的关系,摘取编译时的输出如下:

/openwrt/scripts/kconfig.pl  + + /openwrt/target/linux/generic/config-4.14 /openwrt/target/linux/sunxi/config-4.14 /openwrt/target/linux/sunxi/cortexa7/config-default > /openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_glibc_eabi/linux-sunxi_cortexa7/linux-4.14.63/.config.target
awk '/^(#[[:space:]]+)?CONFIG_KERNEL/{sub("CONFIG_KERNEL_","CONFIG_");print}' /openwrt/.config >> /openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_glibc_eabi/linux-sunxi_cortexa7/linux-4.14.63/.config.target

为理解 openwrt/scripts/kconfig.pl 的用途,创建 A.config B.config C.config

$ cat A.config 
CONFIG_A=y
$ cat B.config 
CONFIG_B=y
$ cat C.config 
CONFIG_C=y
$ /openwrt/scripts/kconfig.pl + + A.config B.config C.config 
CONFIG_A=y
CONFIG_B=y
CONFIG_C=y

可见 /openwrt/scripts/kconfig.pl + + 作用是将三个文件的配置拼成一个。

那当三个文件存在冲突时,输出会怎么样呢。

我们修改 C.config

$ vi C.config 
CONFIG_C=y
CONFIG_B=m

输出如下:

$ /openwrt/scripts/kconfig.pl + + A.config B.config C.config 
CONFIG_A=y
CONFIG_B=m
CONFIG_C=y

可见C.config 会覆盖 B.config

再验证 B 是否覆盖 A

$ vi B.config 
CONFIG_B=y
CONFIG_A=m
$ /openwrt/scripts/kconfig.pl + + A.config B.config C.config 
CONFIG_A=m
CONFIG_B=y
CONFIG_C=y

确实是 B > A

总结:当存在冲突时,优先顺序是 C > B > A 。

kconfig.pl 其它用法

$ cat A.config 
CONFIG_A=y
CONFIG_B=y
CONFIG_ALL=y
$ cat B.config 
CONFIG_B=y
CONFIG_A=m

减法 -

$ /openwrt/scripts/kconfig.pl -  A.config B.config
CONFIG_ALL=y

与 &

$ /openwrt/scripts/kconfig.pl \&  A.config B.config 
CONFIG_B=y

diff >

$ /openwrt/scripts/kconfig.pl \>  A.config B.config 
CONFIG_A=m

m+

$ /openwrt/scripts/kconfig.pl m+ A.config B.config
CONFIG_A=y
CONFIG_ALL=y
CONFIG_B=y

源码

#!/usr/bin/env perl
# 
# Copyright (C) 2006 Felix Fietkau <nbd@nbd.name>
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#

use warnings;
use strict;

my @arg;
my $PREFIX = "CONFIG_";

sub set_config($$$$) {
        my $config = shift;
        my $idx = shift;
        my $newval = shift;
        my $mod_plus = shift;

        if (!defined($config->{$idx}) or !$mod_plus or
            $config->{$idx} eq '#undef' or $newval eq 'y') {
                $config->{$idx} = $newval;
        }
}

sub load_config($$) {
        my $file = shift;
        my $mod_plus = shift;
        my %config;

        open FILE, "$file" or die "can't open file '$file'";
        while (<FILE>) {
                chomp;
                /^$PREFIX(.+?)=(.+)/ and do {
                        set_config(\%config, $1, $2, $mod_plus);
                        next;
                };
                /^# $PREFIX(.+?) is not set/ and do {
                        set_config(\%config, $1, "#undef", $mod_plus);
                        next;
                };
                /^#/ and next;
                /^(.+)$/ and warn "WARNING: can't parse line: $1\n";
        }
        return \%config;
}


sub config_and($$) {
        my $cfg1 = shift;
        my $cfg2 = shift;
        my %config;

        foreach my $config (keys %$cfg1) {
                my $val1 = $cfg1->{$config};
                my $val2 = $cfg2->{$config};
                $val2 and ($val1 eq $val2) and do {
                        $config{$config} = $val1;
                };
        }
        return \%config;
}


sub config_add($$$) {
        my $cfg1 = shift;
        my $cfg2 = shift;
        my $mod_plus = shift;
        my %config;

        for ($cfg1, $cfg2) {
                my %cfg = %$_;

                foreach my $config (keys %cfg) {
                        if ($mod_plus and $config{$config}) {
                                next if $config{$config} eq "y";
                                next if $cfg{$config} eq '#undef';
                        }
                        $config{$config} = $cfg{$config};
                }
        }
        return \%config;
}

sub config_diff($$$) {
        my $cfg1 = shift;
        my $cfg2 = shift;
        my $new_only = shift;
        my %config;

        foreach my $config (keys %$cfg2) {
                if (!defined($cfg1->{$config}) or $cfg1->{$config} ne $cfg2->{$config}) {
                        next if $new_only and !defined($cfg1->{$config}) and $cfg2->{$config} eq '#undef';
                        $config{$config} = $cfg2->{$config};
                }
        }
        return \%config
}

sub config_sub($$) {
        my $cfg1 = shift;
        my $cfg2 = shift;
        my %config = %{$cfg1};

        foreach my $config (keys %$cfg2) {
                delete $config{$config};
        }
        return \%config;
}

sub print_cfgline($$) {
        my $name = shift;
        my $val = shift;
        if ($val eq '#undef' or $val eq 'n') {
                print "# $PREFIX$name is not set\n";
        } else {
                print "$PREFIX$name=$val\n";
        }
}


sub dump_config($) {
        my $cfg = shift;
        die "argument error in dump_config" unless ($cfg);
        my %config = %$cfg;
        foreach my $config (sort keys %config) {
                print_cfgline($config, $config{$config});
        }
}

sub parse_expr {
        my $pos = shift;
        my $mod_plus = shift;
        my $arg = $arg[$$pos++];

        die "Parse error" if (!$arg);

        if ($arg eq '&') {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos);
                return config_and($arg1, $arg2);
        } elsif ($arg =~ /^\+/) {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos);
                return config_add($arg1, $arg2, 0);
        } elsif ($arg =~ /^m\+/) {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos, 1);
                return config_add($arg1, $arg2, 1);
        } elsif ($arg eq '>') {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos);
                return config_diff($arg1, $arg2, 0);
        } elsif ($arg eq '>+') {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos);
                return config_diff($arg1, $arg2, 1);
        } elsif ($arg eq '-') {
                my $arg1 = parse_expr($pos);
                my $arg2 = parse_expr($pos);
                return config_sub($arg1, $arg2);
        } else {
                return load_config($arg, $mod_plus);
        }
}

while (@ARGV > 0 and $ARGV[0] =~ /^-\w+$/) {
        my $cmd = shift @ARGV;
        if ($cmd =~ /^-n$/) {
                $PREFIX = "";
        } elsif ($cmd =~ /^-p$/) {
                $PREFIX = shift @ARGV;
        } else {
                die "Invalid option: $cmd\n";
        }
}
@arg = @ARGV;

my $pos = 0;
dump_config(parse_expr(\$pos));
die "Parse error" if ($arg[$pos]);

标签:CONFIG,kconfig,config,pos,pl,shift,my,openwrt
来源: https://blog.csdn.net/agave7/article/details/116710711