（一百零三）Android O wpa_supplicant初始化學習（二）
阿新 • • 發佈：2018-12-22
前言：之前在（一百零二）Android O wpa_supplicant初始化學習 梳理了對wpa_supplicant 啟動引數的解析以及儲存，對整體的初始化未作探究，繼續梳理一下。
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;
這部分聲明瞭一些區域性變數，之後呼叫os_program_init()進行初始化。看下os_program_init()所做工作。
搜尋發現有5個檔案定義了該方法，看下Android.mk檔案
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
這裡表示如果沒有指定CONFIG_OS巨集，則看下有沒有指定CONFIG_NATIVE_WINDOWS，若指定了那麼CONFIG_OS就是win32，否則是unix。
看到這裡其實對上OS名稱，這裡其實是對作業系統進行區分，另一方面表示wpa_s是支援多作業系統的，比如win32和unix。
本文分析的主要還是Android系統，Android系統在如下config檔案有定義。
vim +248 ./wpa_supplicant/android.config
244 # Select wrapper for operating system and C library specific functions 245 # unix = UNIX/POSIX like systems (default) 246 # win32 = Windows systems 247 # none = Empty template 248 CONFIG_OS=unix
眾所周知，Android底層是基於Linux，屬於unix。
這裡再回頭看下os_program_init()這個方法自然是呼叫的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;
}如何初始化簡單看起來分為2個部分，group和capset的處理。
1）group(參考https://blog.csdn.net/lina_acm/article/details/51911343)
相關函式：initgroups, getgroup, getgid, setgid
標頭檔案：#include <grp.h>
定義函式：int setgroups(size_t size, const gid_t * list);
函式說明：setgroups()用來將list 陣列中所標明的組加入到目前程序的組設定中. 引數size 為list()的gid_t 數目, 最大值為NGROUP(32)。
返回值：設定成功則返回0, 如有錯誤則返回-1.
錯誤程式碼：
EFAULT：引數list 陣列地址不合法.
EPERM：許可權不足, 必須是root 許可權
EINVAL：引數size 值大於NGROUP(32).獲取了wifi的gid、inet的gid和keystore的gid，然後設定了一下。
2）capset(參考https://blog.csdn.net/aa838260772/article/details/39584667)
capset 設定了程序許可權，獲取net相關許可權？
總體說來是許可權相關的設定。
1.2 wpa_supplicant中的log
os_memset(¶ms, 0, sizeof(params));
params.wpa_debug_level = MSG_INFO;這裡定義了wpa_s的初始化log等級為MSG_INFO.
/**
* wpa_debug_level - Debugging verbosity level (e.g., MSG_INFO)
*/
int wpa_debug_level;在 src/utils/wpa_debug.h 中聲明瞭所有等級
/* 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
};簡單看下這個等級的作用，隨便開啟一個wpa_s中帶log的檔案
wpa_printf(MSG_DEBUG, "WPS: Own DH private key not available");該log列印方法是在src/utils/wpa_debug.c中定義的
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 */
}
簡單說來就是和Android一樣，MSG_INFO, MSG_WARNING, MSG_ERROR等級的log才能打印出來。
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__ */
}參考http://www.it610.com/article/4927804.htm
如果使用了pcmcia-cs scripts來啟動wpa_supplicant，這個時候fd 0，1，2是關閉的。（注意: 習慣上，標準輸入fd為0，標準輸出為1，標準錯誤為2）
由於在wpa_supplicant中會使用stdout來輸出，如果不管0,1,2三個檔案描述符可能會出現一些錯誤。
所以，就有了該函式。
下面來分析一下該函式:
如果不使用pcmcia-cs scripts，那麼第一次呼叫fd[i] = open("/dev/null", O_RDWR)時，fd[i]取值就是3（開啟應用程式時，會預設啟動0,1,2三個檔案），第二次就是4...
後面緊跟了一個判斷，如果fd[i]大於2，就close(fd[i])。整個函式相當與什麼都沒有做。
如果使用了pcmcia-cs scripts，依據上面的註釋，三次呼叫fd[i] = open("/dev/null", O_RDWR)時，fd[i]取值就是0,1,2;即相當於，將標準輸入、標準輸出、標準錯誤重定向到/dev/null中。避免了其他socket使用0,1,2這三個檔案描述符而導致的程式出錯。
說的很明白了=-=
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;
}
將之前從配置中讀取的引數賦值初始化。
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;
}從之前可以看到一共有兩個介面，p2p和wifi
vim +699 ./device/google/marlin/init.common.rc
service 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 [email protected]: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
來源：CSDN
原文：https://blog.csdn.net/sinat_20059415/article/details/83449860
版權宣告：本文為博主原創文章，轉載請附上博文連結！
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，後續自己編譯下改下log等級再梳理吧，待續。。。