wpa_supplicant源码剖析-main.c解析

这里记录了 wpa_supplicant 的命令行用法

static void usage(void) { int i; printf("%s\n\n%s\n" "usage:\n" " wpa_supplicant [-BddhKLqq" #ifdef CONFIG_DEBUG_SYSLOG "s" #endif /* CONFIG_DEBUG_SYSLOG */ "t" #ifdef CONFIG_CTRL_IFACE_DBUS_NEW "u" #endif /* CONFIG_CTRL_IFACE_DBUS_NEW */ "vW] [-P<pid file>] " "[-g<global ctrl>] \\\n" " [-G<group>] \\\n" " -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] " "[-p<driver_param>] \\\n" " [-b<br_ifname>] [-e<entropy file>]" #ifdef CONFIG_DEBUG_FILE " [-f<debug file>]" #endif /* CONFIG_DEBUG_FILE */ " \\\n" " [-o<override driver>] [-O<override ctrl>] \\\n" " [-N -i<ifname> -c<conf> [-C<ctrl>] " "[-D<driver>] \\\n" #ifdef CONFIG_P2P " [-m<P2P Device config file>] \\\n" #endif /* CONFIG_P2P */ " [-p<driver_param>] [-b<br_ifname>] [-I<config file>] " "...]\n" "\n" "drivers:\n", wpa_supplicant_version, wpa_supplicant_license); for (i = 0; wpa_drivers[i]; i++) { printf(" %s = %s\n", wpa_drivers[i]->name, wpa_drivers[i]->desc); } #ifndef CONFIG_NO_STDOUT_DEBUG printf("options:\n" " -b = optional bridge interface name\n" " -B = run daemon in the background\n" " -c = Configuration file\n" " -C = ctrl_interface parameter (only used if -c is not)\n" " -d = increase debugging verbosity (-dd even more)\n" " -D = driver name (can be multiple drivers: nl80211,wext)\n" " -e = entropy file\n" #ifdef CONFIG_DEBUG_FILE " -f = log output to debug file instead of stdout\n" #endif /* CONFIG_DEBUG_FILE */ " -g = global ctrl_interface\n" " -G = global ctrl_interface group\n" " -h = show this help text\n" " -i = interface name\n" " -I = additional configuration file\n" " -K = include keys (passwords, etc.) in debug output\n" " -L = show license (BSD)\n" #ifdef CONFIG_P2P " -m = Configuration file for the P2P Device interface\n" #endif /* CONFIG_P2P */ #ifdef CONFIG_MATCH_IFACE " -M = start describing new matching interface\n" #endif /* CONFIG_MATCH_IFACE */ " -N = start describing new interface\n" " -o = override driver parameter for new interfaces\n" " -O = override ctrl_interface parameter for new interfaces\n" " -p = driver parameters\n" " -P = PID file\n" " -q = decrease debugging verbosity (-qq even less)\n" #ifdef CONFIG_DEBUG_SYSLOG " -s = log output to syslog instead of stdout\n" #endif /* CONFIG_DEBUG_SYSLOG */ " -t = include timestamp in debug messages\n" #ifdef CONFIG_DEBUG_LINUX_TRACING " -T = record to Linux tracing in addition to logging\n" " (records all messages regardless of debug verbosity)\n" #endif /* CONFIG_DEBUG_LINUX_TRACING */ #ifdef CONFIG_CTRL_IFACE_DBUS_NEW " -u = enable DBus control interface\n" #endif /* CONFIG_CTRL_IFACE_DBUS_NEW */ " -v = show version\n" " -W = wait for a control interface monitor before starting\n"); printf("example:\n" " wpa_supplicant -D%s -iwlan0 -c/etc/wpa_supplicant.conf\n", wpa_drivers[0] ? wpa_drivers[0]->name : "nl80211"); #endif /* CONFIG_NO_STDOUT_DEBUG */ }

这里会将 0,1,2 文件描述符指向/dev/null，相当于关闭标准输入，标准输出，标准错误

将输入的参数处理完之后，使用参数对 wpa_supplicant 进行初始化

\wpa_supplicant\wpa_supplicant.c

日志相关初始化

注册 eap 协议相关回调函数

填充完用户传下来的参数之后初始化 eloop

这里主要是得到 epollfd 和 kqueuefd

这里进行 random 初始化，random 的作用是生成高质量随机数，可以用于会话加密

初始化全局控制接口

通知 wpa_supplicant 初始化了，这里主要是对 binder 进行初始化，以便于后续进行 rpc，通常手机厂商会在这里将 binder 去掉，加入 hidl 和 aidl 的初始化，一般通过 hidl 接口去调用 wpa_supplicant 的功能

回到 main 函数

这里初始化 fst，fst 是做 ap 切换时会话保持的

添加所有的 wlan 接口

这里面主要是进行驱动初始化及 wpa_supplicant 上下文初始化，后续作者会更新驱动初始化的内容

这里面是注册 wlan 上下文到 dbus，但是手机一般注册到 hidl

回到wpa_supplicant_add_iface

这里是将连接状态机设置为WPA_DISCONNECTED 状态

main 函数的最后去启动 wpa_supplicant