本文共 14530 字，大约阅读时间需要 48 分钟。

前言：之前在 梳理了对wpa_supplicant 启动参数的解析以及存储，对整体的初始化未作探究，继续梳理一下。

 

1.初始化流程梳理

1.1 os_program_init

int main(int argc, char *argv[]){	int c, i;	struct wpa_interface *ifaces, *iface;	int iface_count, exitcode = -1;	struct wpa_params params;	struct wpa_global *global;	if (os_program_init())		return -1;

这部分声明了一些局部变量，之后调用os_program_init()进行初始化。看下os_program_init()所做工作。

搜索发现有5个文件定义了该方法，看下Android.mk文件

137 ifndef CONFIG_OS 138 ifdef CONFIG_NATIVE_WINDOWS 139 CONFIG_OS=win32 140 else 141 CONFIG_OS=unix 142 endif 143 endif 144  145 ifeq ($(CONFIG_OS), internal) 146 L_CFLAGS += -DOS_NO_C_LIB_DEFINES 147 endif 148  149 OBJS += src/utils/os_$(CONFIG_OS).c 150 OBJS_p += src/utils/os_$(CONFIG_OS).c 151 OBJS_c += src/utils/os_$(CONFIG_OS).c

这里表示如果没有指定CONFIG_OS宏，则看下有没有指定CONFIG_NATIVE_WINDOWS，若指定了那么CONFIG_OS就是win32，否则是unix。

看到这里其实对上OS名称，这里其实是对操作系统进行区分，另一方面表示wpa_s是支持多操作系统的，比如win32和unix。

本文分析的主要还是Android系统，Android系统在如下config文件有定义。

vim +248 ./wpa_supplicant/android.config

244 # Select wrapper for operating system and C library specific functions245 # unix = UNIX/POSIX like systems (default)246 # win32 = Windows systems247 # none = Empty template248 CONFIG_OS=unix

众所周知，Android底层是基于Linux，属于unix。

这里再回头看下os_program_init()这个方法自然是调用的os_unix.c中的方法。

int os_program_init(void){#ifdef ANDROID	struct __user_cap_header_struct header;	struct __user_cap_data_struct cap;	struct group *grp = getgrnam("wifi");	gid_t gid_wifi = grp ? grp->gr_gid : 0;	struct passwd *pwd = getpwnam("wifi");	uid_t uid_wifi = pwd ? pwd->pw_uid : 0;	/*	 * We ignore errors here since errors are normal if we	 * are already running as non-root.	 */#ifdef ANDROID_SETGROUPS_OVERRIDE	gid_t groups[] = { ANDROID_SETGROUPS_OVERRIDE };	if (!gid_wifi || !uid_wifi) return -1;#else /* ANDROID_SETGROUPS_OVERRIDE */	gid_t groups[3];	if (!gid_wifi || !uid_wifi) return -1;	groups[0] = gid_wifi;	grp = getgrnam("inet");	groups[1] = grp ? grp->gr_gid : 0;	if (!groups[1]) return -1;	grp = getgrnam("keystore");	groups[2] = grp ? grp->gr_gid : 0;	if (!groups[2]) return -1;#endif /* ANDROID_SETGROUPS_OVERRIDE */	setgroups(ARRAY_SIZE(groups), groups);	prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0);	setgid(gid_wifi);	setuid(uid_wifi);	header.version = _LINUX_CAPABILITY_VERSION;	header.pid = 0;	cap.effective = cap.permitted =		(1 << CAP_NET_ADMIN) | (1 << CAP_NET_RAW);	cap.inheritable = 0;	capset(&header, &cap);#endif /* ANDROID */	return 0;}

如何初始化简单看起来分为2个部分，group和capset的处理。

1）group(参考)

相关函数：initgroups, getgroup, getgid, setgid头文件：#include 
   
    定义函数：int setgroups(size_t size, const gid_t * list);函数说明：setgroups()用来将list 数组中所标明的组加入到目前进程的组设置中. 参数size 为list()的gid_t 数目, 最大值为NGROUP(32)。返回值：设置成功则返回0, 如有错误则返回-1.错误代码：EFAULT：参数list 数组地址不合法.EPERM：权限不足, 必须是root 权限EINVAL：参数size 值大于NGROUP(32).
   

获取了wifi的gid、inet的gid和keystore的gid，然后设置了一下。

2）capset(参考)

capset 设置了进程权限，获取net相关权限？

总体说来是权限相关的设置。

 

1.2 wpa_supplicant中的log

os_memset(&params, 0, sizeof(params));	params.wpa_debug_level = MSG_INFO;

这里定义了wpa_s的初始化log等级为MSG_INFO.

/**	 * wpa_debug_level - Debugging verbosity level (e.g., MSG_INFO)	 */	int wpa_debug_level;

在 src/utils/wpa_debug.h 中声明了所有等级

/* Debugging function - conditional printf and hex dump. Driver wrappers can * use these for debugging purposes. */enum {	MSG_EXCESSIVE, MSG_MSGDUMP, MSG_DEBUG, MSG_INFO, MSG_WARNING, MSG_ERROR};

简单看下这个等级的作用，随便打开一个wpa_s中带log的文件

wpa_printf(MSG_DEBUG, "WPS: Own DH private key not available");

该log打印方法是在src/utils/wpa_debug.c中定义的

void wpa_printf(int level, const char *fmt, ...){	va_list ap;	va_start(ap, fmt);	if (level >= wpa_debug_level) {#ifdef CONFIG_ANDROID_LOG		__android_log_vprint(wpa_to_android_level(level),				     ANDROID_LOG_NAME, fmt, ap);#else /* CONFIG_ANDROID_LOG */#ifdef CONFIG_DEBUG_SYSLOG		if (wpa_debug_syslog) {			vsyslog(syslog_priority(level), fmt, ap);		} else {#endif /* CONFIG_DEBUG_SYSLOG */		wpa_debug_print_timestamp();#ifdef CONFIG_DEBUG_FILE		if (out_file) {			vfprintf(out_file, fmt, ap);			fprintf(out_file, "\n");		} else {#endif /* CONFIG_DEBUG_FILE */		vprintf(fmt, ap);		printf("\n");#ifdef CONFIG_DEBUG_FILE		}#endif /* CONFIG_DEBUG_FILE */#ifdef CONFIG_DEBUG_SYSLOG		}#endif /* CONFIG_DEBUG_SYSLOG */#endif /* CONFIG_ANDROID_LOG */	}	va_end(ap);#ifdef CONFIG_DEBUG_LINUX_TRACING	if (wpa_debug_tracing_file != NULL) {		va_start(ap, fmt);		fprintf(wpa_debug_tracing_file, WPAS_TRACE_PFX, level);		vfprintf(wpa_debug_tracing_file, fmt, ap);		fprintf(wpa_debug_tracing_file, "\n");		fflush(wpa_debug_tracing_file);		va_end(ap);	}#endif /* CONFIG_DEBUG_LINUX_TRACING */}

简单说来就是和Android一样，MSG_INFO, MSG_WARNING, MSG_ERROR等级的log才能打印出来。

 

1.3 wpa_supplicant_fd_workaround

static void wpa_supplicant_fd_workaround(int start){#ifdef __linux__	static int fd[3] = { -1, -1, -1 };	int i;	/* When started from pcmcia-cs scripts, wpa_supplicant might start with	 * fd 0, 1, and 2 closed. This will cause some issues because many	 * places in wpa_supplicant are still printing out to stdout. As a	 * workaround, make sure that fd's 0, 1, and 2 are not used for other	 * sockets. */	if (start) {		for (i = 0; i < 3; i++) {			fd[i] = open("/dev/null", O_RDWR);			if (fd[i] > 2) {				close(fd[i]);				fd[i] = -1;				break;			}		}	} else {		for (i = 0; i < 3; i++) {			if (fd[i] >= 0) {				close(fd[i]);				fd[i] = -1;			}		}	}#endif /* __linux__ */}

参考

如果使用了pcmcia-cs scripts来启动wpa_supplicant，这个时候fd 0，1，2是关闭的。（注意: 习惯上，标准输入fd为0，标准输出为1，标准错误为2） 

由于在wpa_supplicant中会使用stdout来输出，如果不管0,1,2三个文件描述符可能会出现一些错误。  所以，就有了该函数。  下面来分析一下该函数:  如果不使用pcmcia-cs scripts，那么第一次调用fd[i] = open("/dev/null", O_RDWR)时，fd[i]取值就是3（开启应用程序时，会默认启动0,1,2三个文件），第二次就是4...  后面紧跟了一个判断，如果fd[i]大于2，就close(fd[i])。整个函数相当与什么都没有做。  如果使用了pcmcia-cs scripts，依据上面的注释，三次调用fd[i] = open("/dev/null", O_RDWR)时，fd[i]取值就是0,1,2;即相当于，将标准输入、标准输出、标准错误重定向到/dev/null中。避免了其他socket使用0,1,2这三个文件描述符而导致的程序出错。 

说的很明白了=-=

 

1.4 wpa_supplicant_init

/** * wpa_supplicant_init - Initialize %wpa_supplicant * @params: Parameters for %wpa_supplicant * Returns: Pointer to global %wpa_supplicant data, or %NULL on failure * * This function is used to initialize %wpa_supplicant. After successful * initialization, the returned data pointer can be used to add and remove * network interfaces, and eventually, to deinitialize %wpa_supplicant. */struct wpa_global * wpa_supplicant_init(struct wpa_params *params){	struct wpa_global *global;	int ret, i;	if (params == NULL)		return NULL;#ifdef CONFIG_DRIVER_NDIS	{		void driver_ndis_init_ops(void);		driver_ndis_init_ops();	}#endif /* CONFIG_DRIVER_NDIS */#ifndef CONFIG_NO_WPA_MSG	wpa_msg_register_ifname_cb(wpa_supplicant_msg_ifname_cb);#endif /* CONFIG_NO_WPA_MSG */	if (params->wpa_debug_file_path)		wpa_debug_open_file(params->wpa_debug_file_path);	else		wpa_debug_setup_stdout();	if (params->wpa_debug_syslog)		wpa_debug_open_syslog();	if (params->wpa_debug_tracing) {		ret = wpa_debug_open_linux_tracing();		if (ret) {			wpa_printf(MSG_ERROR,				   "Failed to enable trace logging");			return NULL;		}	}	ret = eap_register_methods();	if (ret) {		wpa_printf(MSG_ERROR, "Failed to register EAP methods");		if (ret == -2)			wpa_printf(MSG_ERROR, "Two or more EAP methods used "				   "the same EAP type.");		return NULL;	}	global = os_zalloc(sizeof(*global));	if (global == NULL)		return NULL;	dl_list_init(&global->p2p_srv_bonjour);	dl_list_init(&global->p2p_srv_upnp);	global->params.daemonize = params->daemonize;	global->params.wait_for_monitor = params->wait_for_monitor;	global->params.dbus_ctrl_interface = params->dbus_ctrl_interface;	if (params->pid_file)		global->params.pid_file = os_strdup(params->pid_file);	if (params->ctrl_interface)		global->params.ctrl_interface =			os_strdup(params->ctrl_interface);	if (params->ctrl_interface_group)		global->params.ctrl_interface_group =			os_strdup(params->ctrl_interface_group);	if (params->override_driver)		global->params.override_driver =			os_strdup(params->override_driver);	if (params->override_ctrl_interface)		global->params.override_ctrl_interface =			os_strdup(params->override_ctrl_interface);#ifdef CONFIG_MATCH_IFACE	global->params.match_iface_count = params->match_iface_count;	if (params->match_iface_count) {		global->params.match_ifaces =			os_calloc(params->match_iface_count,				  sizeof(struct wpa_interface));		os_memcpy(global->params.match_ifaces,			  params->match_ifaces,			  params->match_iface_count *			  sizeof(struct wpa_interface));	}#endif /* CONFIG_MATCH_IFACE */#ifdef CONFIG_P2P	if (params->conf_p2p_dev)		global->params.conf_p2p_dev =			os_strdup(params->conf_p2p_dev);#endif /* CONFIG_P2P */	wpa_debug_level = global->params.wpa_debug_level =		params->wpa_debug_level;	wpa_debug_show_keys = global->params.wpa_debug_show_keys =		params->wpa_debug_show_keys;	wpa_debug_timestamp = global->params.wpa_debug_timestamp =		params->wpa_debug_timestamp;	wpa_printf(MSG_DEBUG, "wpa_supplicant v" VERSION_STR);	if (eloop_init()) {		wpa_printf(MSG_ERROR, "Failed to initialize event loop");		wpa_supplicant_deinit(global);		return NULL;	}	random_init(params->entropy_file);	global->ctrl_iface = wpa_supplicant_global_ctrl_iface_init(global);	if (global->ctrl_iface == NULL) {		wpa_supplicant_deinit(global);		return NULL;	}	if (wpas_notify_supplicant_initialized(global)) {		wpa_supplicant_deinit(global);		return NULL;	}	for (i = 0; wpa_drivers[i]; i++)		global->drv_count++;	if (global->drv_count == 0) {		wpa_printf(MSG_ERROR, "No drivers enabled");		wpa_supplicant_deinit(global);		return NULL;	}	global->drv_priv = os_calloc(global->drv_count, sizeof(void *));	if (global->drv_priv == NULL) {		wpa_supplicant_deinit(global);		return NULL;	}#ifdef CONFIG_WIFI_DISPLAY	if (wifi_display_init(global) < 0) {		wpa_printf(MSG_ERROR, "Failed to initialize Wi-Fi Display");		wpa_supplicant_deinit(global);		return NULL;	}#endif /* CONFIG_WIFI_DISPLAY */	eloop_register_timeout(WPA_SUPPLICANT_CLEANUP_INTERVAL, 0,			       wpas_periodic, global, NULL);	return global;}

将之前从配置中读取的参数赋值初始化。

 

1.5 wpa_supplicant_add_iface

/** * wpa_supplicant_add_iface - Add a new network interface * @global: Pointer to global data from wpa_supplicant_init() * @iface: Interface configuration options * @parent: Parent interface or %NULL to assign new interface as parent * Returns: Pointer to the created interface or %NULL on failure * * This function is used to add new network interfaces for %wpa_supplicant. * This can be called before wpa_supplicant_run() to add interfaces before the * main event loop has been started. In addition, new interfaces can be added * dynamically while %wpa_supplicant is already running. This could happen, * e.g., when a hotplug network adapter is inserted. */struct wpa_supplicant * wpa_supplicant_add_iface(struct wpa_global *global,						 struct wpa_interface *iface,						 struct wpa_supplicant *parent){	struct wpa_supplicant *wpa_s;	struct wpa_interface t_iface;	struct wpa_ssid *ssid;	if (global == NULL || iface == NULL)		return NULL;	wpa_s = wpa_supplicant_alloc(parent);	if (wpa_s == NULL)		return NULL;	wpa_s->global = global;	t_iface = *iface;	if (global->params.override_driver) {		wpa_printf(MSG_DEBUG, "Override interface parameter: driver "			   "('%s' -> '%s')",			   iface->driver, global->params.override_driver);		t_iface.driver = global->params.override_driver;	}	if (global->params.override_ctrl_interface) {		wpa_printf(MSG_DEBUG, "Override interface parameter: "			   "ctrl_interface ('%s' -> '%s')",			   iface->ctrl_interface,			   global->params.override_ctrl_interface);		t_iface.ctrl_interface =			global->params.override_ctrl_interface;	}	if (wpa_supplicant_init_iface(wpa_s, &t_iface)) {		wpa_printf(MSG_DEBUG, "Failed to add interface %s",			   iface->ifname);		wpa_supplicant_deinit_iface(wpa_s, 0, 0);		return NULL;	}	/* Notify the control interfaces about new iface */	if (wpas_notify_iface_added(wpa_s)) {		wpa_supplicant_deinit_iface(wpa_s, 1, 0);		return NULL;	}	/* Notify the control interfaces about new networks for non p2p mgmt	 * ifaces. */	if (iface->p2p_mgmt == 0) {		for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next)			wpas_notify_network_added(wpa_s, ssid);	}	wpa_s->next = global->ifaces;	global->ifaces = wpa_s;	wpa_dbg(wpa_s, MSG_DEBUG, "Added interface %s", wpa_s->ifname);	wpa_supplicant_set_state(wpa_s, WPA_DISCONNECTED);#ifdef CONFIG_P2P	if (wpa_s->global->p2p == NULL &&	    !wpa_s->global->p2p_disabled && !wpa_s->conf->p2p_disabled &&	    (wpa_s->drv_flags & WPA_DRIVER_FLAGS_DEDICATED_P2P_DEVICE) &&	    wpas_p2p_add_p2pdev_interface(		    wpa_s, wpa_s->global->params.conf_p2p_dev) < 0) {		wpa_printf(MSG_INFO,			   "P2P: Failed to enable P2P Device interface");		/* Try to continue without. P2P will be disabled. */	}#endif /* CONFIG_P2P */	return wpa_s;}

从之前可以看到一共有两个接口，p2p和wifi

vim +699 ./device/google/marlin/init.common.rcservice wpa_supplicant /vendor/bin/hw/wpa_supplicant \    -ip2p0 -Dnl80211 -c/data/misc/wifi/p2p_supplicant.conf \    -I/vendor/etc/wifi/p2p_supplicant_overlay.conf -N \    -iwlan0 -Dnl80211 -c/data/misc/wifi/wpa_supplicant.conf \    -I/vendor/etc/wifi/wpa_supplicant_overlay.conf \    -O/data/misc/wifi/sockets -puse_p2p_group_interface=1 \    -e/data/misc/wifi/entropy.bin -g@android:wpa_wlan0#   we will start as root and wpa_supplicant will switch to user wifi#   after setting up the capabilities required for WEXT#   user wifi#   group wifi inet keystore    class main    socket wpa_wlan0 dgram 660 wifi wifi    disabled    oneshot--------------------- 作者：i加加 来源：CSDN 原文：https://blog.csdn.net/sinat_20059415/article/details/83449860 版权声明：本文为博主原创文章，转载请附上博文链接！

 

1.6 wpa_supplicant_run

/** * wpa_supplicant_run - Run the %wpa_supplicant main event loop * @global: Pointer to global data from wpa_supplicant_init() * Returns: 0 after successful event loop run, -1 on failure * * This function starts the main event loop and continues running as long as * there are any remaining events. In most cases, this function is running as * long as the %wpa_supplicant process in still in use. */int wpa_supplicant_run(struct wpa_global *global){	struct wpa_supplicant *wpa_s;	if (global->params.daemonize &&	    (wpa_supplicant_daemon(global->params.pid_file) ||	     eloop_sock_requeue()))		return -1;#ifdef CONFIG_MATCH_IFACE	if (wpa_supplicant_match_existing(global))		return -1;#endif	if (global->params.wait_for_monitor) {		for (wpa_s = global->ifaces; wpa_s; wpa_s = wpa_s->next)			if (wpa_s->ctrl_iface && !wpa_s->p2p_mgmt)				wpa_supplicant_ctrl_iface_wait(					wpa_s->ctrl_iface);	}	eloop_register_signal_terminate(wpa_supplicant_terminate, global);	eloop_register_signal_reconfig(wpa_supplicant_reconfig, global);	eloop_run();	return 0;}

 

有很多debug的log，后续自己编译下改下log等级再梳理吧，待续。。。

 

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