static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
inherited = (u_char *) getenv(NGINX_VAR);
if (inherited == NULL) {
return NGX_OK;
}
printf("inherited: %s\n", inherited);
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
for (p = inherited, v = p; *p; p++) {
if (*p == ':' || *p == ';') {
s = ngx_atoi(v, p - v);
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
v = p + 1;
ls = ngx_array_push(&cycle->listening);
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;
}
}
if (v != p) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring", v);
}
ngx_inherited = 1;
return ngx_set_inherited_sockets(cycle);
}
// 参考:http://blog.csdn.net/livelylittlefish/article/details/7277607
static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
inherited = (u_char *) getenv(NGINX_VAR); // 从environ 中查看是否设置了NGINX_VAR这个环境变量。若设置了，则要SOCKET继承
if (inherited == NULL) {
return NGX_OK;
}
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
// 为了便于调试，设置 export NGINX="16000:16500:16600;"
for (p = inherited, v = p; *p; p++) {
if (*p == ':' || *p == ';') {
s = ngx_atoi(v, p - v);
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
v = p + 1;
ls = ngx_array_push(&cycle->listening);
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;
}
}
// 全局变量，定义于/os/unix/ngx_process_cycle.c 文件中
ngx_inherited = 1;
// 定义于./core/ngx_connection.c 文件中
return ngx_set_inherited_sockets(cycle);
}
/*继承socket*/
static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
//#define NGINX_VAR "NGINX"
inherited = (u_char *) getenv(NGINX_VAR); // 查看是否有设置NGINX这个环境变量
if (inherited == NULL) {//直接返回
return NGX_OK;
}
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
for (p = inherited, v = p; *p; p++) {
if (*p == ':' || *p == ';') { //通过冒号或分号去除列表中的socket
s = ngx_atoi(v, p - v);
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
v = p + 1;
ls = ngx_array_push(&cycle->listening); //保存取出来的socket
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;
}
}
ngx_inherited = 1; //标记继承工作的结束
return ngx_set_inherited_sockets(cycle);
}
/*
图8-6中的第2步实际上就是在调用表812中的ngx_add_inherited_ sockets方法。Nginx在不重启服务升级时，也就是我们说过的平滑升级（参见1.9节）时，
它会不重启master进程而启动新版本的Nginx程序。这样，旧版本的master进程会通过execve系统调用来启动新版本的master进程（先fork出子进程再
调用exec来运行新程序），这时旧版本的master进程必须要通过一种方式告诉新版本的master进程这是在平滑升级，并且传递一些必要的信息。Nginx是通过环
境变量来传递这些信息的，新版本的master进程通过ngx_add_inherited_sockets方法由环境变量里读取平滑升级信息，并对旧版本Nginx服务监听的句柄做继承处理。
*/
static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
//getenv()用来取得参数envvar环境变量的内容。参数envvar为环境变量的名称，如果该变量存在则会返回指向该内容的指针
inherited = (u_char *) getenv(NGINX_VAR); //获取环境变量 这里的"NGINX_VAR"是宏定义，值为"NGINX"
if (inherited == NULL) {
return NGX_OK;
}
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
//初始化ngx_cycle.listening数组，并且数组中包含10个元素
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
for (p = inherited, v = p; *p; p++) { //遍历环境变量
if (*p == ':' || *p == ';') {//环境变量的值以':'or';'分开
s = ngx_atoi(v, p - v); //转换十进制sockets
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
v = p + 1;
ls = ngx_array_push(&cycle->listening); //返回新分配的数组指针地址(在参考的blog里面这里解释可能有点错误)
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;//保存socket文件描述符到数组中
}
}
ngx_inherited = 1; //表示已经的得到要继承的socket
return ngx_set_inherited_sockets(cycle);
}
/*
* Nginx在不重启服务升级时，即平滑升级的时候，它会不重启master进程而启动新版本的nginx程序。
* 这样旧版本的master进程会通过execve系统调用来启动新版本的master进程。这是旧版本的master
* 进程必须通过一种方式告诉新版本的master进程这是在平滑升级，并且传递一些必要的信息。Nginx
* 是通过环境变量(NGINX)来传递这些信息的。新版本的master进程通过ngx_add_inherited_sockets()
* 方法由环境变量里读取平滑升级信息，并对旧版本Nginx服务监听的句柄做继承处理。
*/
static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
/*获取环境变量,NGINX*/
inherited = (u_char *) getenv(NGINX_VAR);
/*如果inherited为NULL，表明不是平滑升级，及环境变量NGINX是空的*/
if (inherited == NULL) {
return NGX_OK;
}
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
/*初始化cycle->listening动态数组，初始情况下为十个ngx_listening_t元素*/
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
/*遍历环境变量，获取旧版本Nginx服务所监听的socket句柄，做继承处理*/
for (p = inherited, v = p; *p; p++) {
if (*p == ':' || *p == ';') {
s = ngx_atoi(v, p - v); //字符串转整数
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
/*在这个循环遍历处理过程中，v始终都指向下一个待转换的字符串形式的socket句柄的开始处*/
/*这种处理方法值得学习*/
v = p + 1;
/*将解析得到的socket句柄存放在动态数组cycle->listening中*/
ls = ngx_array_push(&cycle->listening);
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;
}
}
if (v != p) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring", v);
}
ngx_inherited = 1; //对旧版本nginx服务监听的socket句柄进行了继承标志位。
/*根据从旧版本Nginx中继承来的socket句柄，初始化socket对应的ngx_listening_t结构体的成员*/
return ngx_set_inherited_sockets(cycle);
}
// 检查NGINX环境变量，获取之前监听的socket
static ngx_int_t
ngx_add_inherited_sockets(ngx_cycle_t *cycle)
{
u_char *p, *v, *inherited;
ngx_int_t s;
ngx_listening_t *ls;
// 获取环境变量，NGINX_VAR定义在nginx.h，值是"NGINX"
inherited = (u_char *) getenv(NGINX_VAR);
// 无变量则直接
if (inherited == NULL) {
return NGX_OK;
}
ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
"using inherited sockets from \"%s\"", inherited);
// 清空cycle的监听端口数组
if (ngx_array_init(&cycle->listening, cycle->pool, 10,
sizeof(ngx_listening_t))
!= NGX_OK)
{
return NGX_ERROR;
}
// 从环境变量字符串里切分出socket
for (p = inherited, v = p; *p; p++) {
// 分隔符是:/;
if (*p == ':' || *p == ';') {
s = ngx_atoi(v, p - v);
if (s == NGX_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring the rest"
" of the variable", v);
break;
}
v = p + 1;
ls = ngx_array_push(&cycle->listening);
if (ls == NULL) {
return NGX_ERROR;
}
ngx_memzero(ls, sizeof(ngx_listening_t));
ls->fd = (ngx_socket_t) s;
}
}
if (v != p) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"invalid socket number \"%s\" in " NGINX_VAR
" environment variable, ignoring", v);
}
ngx_inherited = 1;
// in ngx_connection.c
return ngx_set_inherited_sockets(cycle);
}
