低成本嵌入式Linux开发方案：通过配置文件实现参数设置

在产品出厂时通常会默认一套基本参数配置，但为了尽可能适配每个用户的不同应用场景，最好有一个建议的修改配置的方式而不需要修改核心系统。

通常情况下，通过设置一个config.json的配置文件，让用户修改这个文件即可完成系统参数配置。

本文实现了一个简易的配置功能，即系统上电之后从TF卡中读取config.json配置文件，然后根据配置文件更新系统配置

逐步配置

配置/mnt/sdcard/config.json文件

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{
    "Network": {
        "address": "192.168.137.10",
        "netmask": "255.255.255.0",
        "gateway": "192.168.137.1",
        "dns": ["192.168.137.1", "8.8.8.8", "8.8.4.4"]
    }
}

配置/usr/bin/configure_network.sh文件

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nano /usr/bin/configure_network.sh

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#!/bin/sh

# 配置文件路径
CONFIG_FILE="/mnt/sdcard/config.json"
LOG_FILE="/var/log/network_config.log"

# 创建日志函数
log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

# 检查配置文件是否存在
if [ ! -f "$CONFIG_FILE" ]; then
    log "错误：配置文件 $CONFIG_FILE 不存在!"
    exit 1
fi

# 提取配置值的函数
get_config_value() {
    # $1 = JSON 键名
    grep "\"$1\":" "$CONFIG_FILE" | \
    awk -F': ' '{print $2}' | \
    sed 's/[",]//g' | \
    tr -d ' '
}

# 提取DNS服务器列表 - 修复版本
get_dns_servers() {
    # 提取dns数组部分
    awk '/"dns": \[/,/\]/' "$CONFIG_FILE" | \
    grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+'
}

# 提取配置
log "从配置文件提取网络设置..."
ADDRESS=$(get_config_value "address")
NETMASK=$(get_config_value "netmask")
GATEWAY=$(get_config_value "gateway")
DNS_SERVERS=$(get_dns_servers)

log "解析的配置:"
log "  IP地址: ${ADDRESS:-未找到}"
log "  子网掩码: ${NETMASK:-未找到}"
log "  网关: ${GATEWAY:-未找到}"
log "  DNS服务器: ${DNS_SERVERS:-未找到}"

# 验证配置是否可用
if [ -z "$ADDRESS" ] || [ -z "$NETMASK" ] || [ -z "$GATEWAY" ] || [ -z "$DNS_SERVERS" ]; then
    log "错误：关键网络参数缺失!"
    exit 2
fi

# 配置网络接口
log "配置 eth0..."
ifconfig eth0 "$ADDRESS" netmask "$NETMASK"

# 配置网关
log "设置默认网关..."
route add default gw "$GATEWAY" >/dev/null 2>&1

# 配置DNS
log "更新 DNS 配置..."
echo "# Generated by network config script" > /etc/resolv.conf
for server in $DNS_SERVERS; do
    echo "nameserver $server" >> /etc/resolv.conf
done

# 验证配置
log "验证网络配置:"
ifconfig eth0 | grep -q "inet addr:$ADDRESS" && log "IP地址配置成功" || log "IP地址配置失败"
ip route | grep -q "default via $GATEWAY" && log "网关配置成功" || log "网关配置失败"
grep -q "$GATEWAY" /etc/resolv.conf && log "DNS配置成功" || log "DNS配置失败"

log "网络配置完成!"

添加权限

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chmod +x /usr/bin/configure_network.sh

创建日志文件

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mkdir -p /var/log

测试运行脚本

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/usr/bin/configure_network.sh

创建自启动文件

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nano /etc/init.d/S99network-config

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#!/bin/sh

start() {
    echo "Starting network configuration"
    # 等待网络接口可用
    while [ ! -e /sys/class/net/eth0 ]; do
        sleep 1
    done
    # 等待TF卡挂载
    sleep 3
    /usr/bin/configure_network.sh
}

stop() {
    echo "Stopping network configuration service"
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart|reload)
        stop
        start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart}"
        exit 1
esac

exit 0

加权限

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chmod +x /etc/init.d/S99network-config

创建目录

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mkdir -p /etc/rc.d

链接文件

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ln -s /etc/init.d/S99network-config /etc/rc.d/S99network-config

测试自启动

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/etc/init.d/S99network-config start

一键脚本

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nano setup.sh

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#!/bin/sh

# 创建并配置网络设置脚本
cat > /usr/bin/configure_network.sh << 'EOF'
#!/bin/sh

# 配置文件路径
CONFIG_FILE="/mnt/sdcard/config.json"
LOG_FILE="/var/log/network_config.log"

# 创建日志函数
log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

# 检查配置文件是否存在
if [ ! -f "$CONFIG_FILE" ]; then
    log "错误：配置文件 $CONFIG_FILE 不存在!"
    exit 1
fi

# 提取配置值的函数
get_config_value() {
    # $1 = JSON 键名
    grep "\"$1\":" "$CONFIG_FILE" | \
    awk -F': ' '{print $2}' | \
    sed 's/[",]//g' | \
    tr -d ' '
}

# 提取DNS服务器列表
get_dns_servers() {
    # 提取dns数组部分
    awk '/"dns": \[/,/\]/' "$CONFIG_FILE" | \
    grep -Eo '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+'
}

# 提取配置
log "从配置文件提取网络设置..."
ADDRESS=$(get_config_value "address")
NETMASK=$(get_config_value "netmask")
GATEWAY=$(get_config_value "gateway")
DNS_SERVERS=$(get_dns_servers)

log "解析的配置:"
log "  IP地址: ${ADDRESS:-未找到}"
log "  子网掩码: ${NETMASK:-未找到}"
log "  网关: ${GATEWAY:-未找到}"
log "  DNS服务器: ${DNS_SERVERS:-未找到}"

# 验证配置是否可用
if [ -z "$ADDRESS" ] || [ -z "$NETMASK" ] || [ -z "$GATEWAY" ] || [ -z "$DNS_SERVERS" ]; then
    log "错误：关键网络参数缺失!"
    exit 2
fi

# 配置网络接口
log "配置 eth0..."
ifconfig eth0 "$ADDRESS" netmask "$NETMASK"

# 配置网关
log "设置默认网关..."
route add default gw "$GATEWAY" >/dev/null 2>&1

# 配置DNS
log "更新 DNS 配置..."
echo "# Generated by network config script" > /etc/resolv.conf
for server in $DNS_SERVERS; do
    echo "nameserver $server" >> /etc/resolv.conf
done

# 验证配置
log "验证网络配置:"
ifconfig eth0 | grep -q "inet addr:$ADDRESS" && log "IP地址配置成功" || log "IP地址配置失败"
ip route | grep -q "default via $GATEWAY" && log "网关配置成功" || log "网关配置失败"
grep -q "$GATEWAY" /etc/resolv.conf && log "DNS配置成功" || log "DNS配置失败"

log "网络配置完成!"
EOF

# 设置权限
chmod +x /usr/bin/configure_network.sh

# 创建日志目录
mkdir -p /var/log

# 创建自启动服务文件
cat > /etc/init.d/S99network-config << 'EOF'
#!/bin/sh

start() {
    echo "Starting network configuration"
    # 等待网络接口可用
    while [ ! -e /sys/class/net/eth0 ]; do
        sleep 1
    done
    # 等待TF卡挂载
    sleep 3
    /usr/bin/configure_network.sh
}

stop() {
    echo "Stopping network configuration service"
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart|reload)
        stop
        start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart}"
        exit 1
esac

exit 0
EOF

# 设置服务权限
chmod +x /etc/init.d/S99network-config

# 创建rc.d目录（如果不存在）
mkdir -p /etc/rc.d

# 创建符号链接
ln -sf /etc/init.d/S99network-config /etc/rc.d/S99network-config

# 测试服务
echo "正在测试网络配置服务..."
/etc/init.d/S99network-config start

echo "所有配置已完成！"
echo "网络配置脚本已安装到 /usr/bin/configure_network.sh"
echo "自启动服务已安装到 /etc/init.d/S99network-config"

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chmod +x setup.sh

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./setup.sh