nginx设计解读--模块化设计及程序初始化

本文链接：https://blog.youkuaiyun.com/qiuxuezhong06/article/details/47082951

Nginx依赖的库如下：

[qxz@qiuxuezhong-test-dev001-sjhl tools]$ldd /usr/local/nginx/sbin/nginx

linux-vdso.so.1=> (0x00007fffbbfff000)

libpthread.so.0=> /lib64/libpthread.so.0 (0x0000003267c00000)

libcrypt.so.1=> /lib64/libcrypt.so.1 (0x0000003269800000)

libpcre.so.1=> /usr/local/lib/libpcre.so.1 (0x00002b23b7b4a000)

libcrypto.so.10=> /usr/lib64/libcrypto.so.10 (0x0000003e2b400000)

libz.so.1=> /lib64/libz.so.1 (0x0000003268000000)

libc.so.6=> /lib64/libc.so.6 (0x0000003267400000)

/lib64/ld-linux-x86-64.so.2(0x0000003267000000)

libfreebl3.so=> /usr/lib64/libfreebl3.so (0x0000003269c00000)

libdl.so.2=> /lib64/libdl.so.2 (0x0000003267800000)

ngx_cycle_s包含了内存池、连接池、文件等，因此属于资源的管理者，应该是pbrpc中的RpcServer

struct ngx_cycle_s {

void ****conf_ctx;

ngx_pool_t *pool;

ngx_log_t *log;

ngx_log_t new_log;

ngx_uint_t log_use_stderr; /* unsigned log_use_stderr:1; */

ngx_connection_t **files;

ngx_connection_t *free_connections;

ngx_uint_t free_connection_n;

ngx_queue_t reusable_connections_queue;

ngx_array_t listening;

ngx_array_t paths;

ngx_list_t open_files;

ngx_list_t shared_memory;

ngx_uint_t connection_n;

ngx_uint_t files_n;

ngx_connection_t *connections;

ngx_event_t *read_events;

ngx_event_t *write_events;

ngx_cycle_t *old_cycle;

ngx_str_t conf_file;

ngx_str_t conf_param;

ngx_str_t conf_prefix;

ngx_str_t prefix;

ngx_str_t lock_file;

ngx_str_t hostname;

};

其中conf_ctx;为甚要用4级指针？

ngx_add_inherited_sockets函数中，查看了是否有环境变量NGINX,用于识别是否需要平滑升级。

Nginx注册模块是在main函数之前，

如下：

3 = 0

(gdb) watch ngx_max_module

Hardware watchpoint 2: ngx_max_module

(gdb) p ngx_modules[0]

$4 = (ngx_module_t *) 0x6806c0<ngx_core_module>

(gdb) p ngx_modules[1]

$5 = (ngx_module_t *) 0x680c60<ngx_errlog_module>

(gdb) p ngx_modules[2]

$6 = (ngx_module_t *) 0x6815c0<ngx_conf_module>

(gdb) p ngx_modules[4]

$7 = (ngx_module_t *) 0x681720<ngx_event_core_module>

(gdb) p ngx_modules[5]

$8 = (ngx_module_t *) 0x681e20<ngx_epoll_module>

(gdb) p ngx_modules[6]

$9 = (ngx_module_t *) 0x682060<ngx_regex_module>

(gdb) p ngx_modules[7]

$10 = (ngx_module_t *) 0x6821e0<ngx_http_module>

(gdb) p ngx_modules[8]

$11 = (ngx_module_t *) 0x6824c0<ngx_http_core_module>

(gdb) p ngx_modules[9]

$12 = (ngx_module_t *) 0x685ce0<ngx_http_log_module>

(gdb) p ngx_modules[11]

$13 = (ngx_module_t *) 0x6877a0<ngx_http_static_module>

(gdb) p ngx_modules[10]

$14 = (ngx_module_t *) 0x687000<ngx_http_upstream_module>

(gdb) p ngx_modules[12]

$15 = (ngx_module_t *) 0x689660<ngx_http_autoindex_module>

(gdb) p ngx_modules[13]

$16 = (ngx_module_t *) 0x6878c0<ngx_http_index_module>

(gdb) p ngx_modules[14]

$17 = (ngx_module_t *) 0x689860<ngx_http_auth_basic_module>

(gdb) p ngx_modules[1]

$18 = (ngx_module_t *) 0x680c60<ngx_errlog_module>

(gdb) p ngx_modules[15]

$19 = (ngx_module_t *) 0x689a40<ngx_http_access_module>

(gdb) p ngx_modules[16]

$20 = (ngx_module_t *) 0x689c20<ngx_http_limit_conn_module>

(gdb) p ngx_modules[17]

$21 = (ngx_module_t *) 0x689f60<ngx_http_limit_req_module>

(gdb) p ngx_modules[18]

$22 = (ngx_module_t *) 0x68a260<ngx_http_geo_module>

(gdb) p ngx_modules[19]

$23 = (ngx_module_t *) 0x68a3c0<ngx_http_map_module>

(gdb) p ngx_modules[20]

$24 = (ngx_module_t *) 0x68a5c0<ngx_http_split_clients_module>

(gdb) p ngx_modules[21]

$25 = (ngx_module_t *) 0x68a720<ngx_http_referer_module>

(gdb) p ngx_modules[22]

$26 = (ngx_module_t *) 0x68a920<ngx_http_rewrite_module>

(gdb) p ngx_modules[23]

$27 = (ngx_module_t *) 0x68bb00<ngx_http_proxy_module>

(gdb) p ngx_modules[24]

$28 = (ngx_module_t *) 0x68c940<ngx_http_fastcgi_module>

(gdb) p ngx_modules[25]

$29 = (ngx_module_t *) 0x68d580<ngx_http_uwsgi_module>

(gdb) p ngx_modules[26]

$30 = (ngx_module_t *) 0x68e140<ngx_http_scgi_module>

(gdb) p ngx_modules[27]

$31 = (ngx_module_t *) 0x68e340<ngx_http_memcached_module>

(gdb) p ngx_modules[28]

$32 = (ngx_module_t *) 0x68e720<ngx_http_empty_gif_module>

(gdb) p ngx_modules[29]

$33 = (ngx_module_t *) 0x68ea60<ngx_http_browser_module>

(gdb) p ngx_modules[30]

$34 = (ngx_module_t *) 0x68eca0<ngx_http_upstream_ip_hash_module>

(gdb) p ngx_modules[31]

$35 = (ngx_module_t *) 0x68ee00<ngx_http_upstream_least_conn_module>

(gdb) p ngx_modules[32]

$36 = (ngx_module_t *) 0x68efa0<ngx_http_upstream_keepalive_module>

(gdb) p ngx_modules[33]

$37 = (ngx_module_t *) 0x6858c0<ngx_http_write_filter_module>

(gdb) p ngx_modules[34]

$38 = (ngx_module_t *) 0x6857a0<ngx_http_header_filter_module>

(gdb) p ngx_modules[35]

$39 = (ngx_module_t *) 0x687a60<ngx_http_chunked_filter_module>

(gdb) p ngx_modules[36]

$40 = (ngx_module_t *) 0x687ca0<ngx_http_range_header_filter_module>

(gdb) p ngx_modules[37]

$41 = (ngx_module_t *) 0x6881e0<ngx_http_gzip_filter_module>

(gdb) p ngx_modules[50]

$42 = (ngx_module_t *) 0x326747a8a0<malloc>

(gdb) p ngx_modules[40]

$43 = (ngx_module_t *) 0x688ea0<ngx_http_charset_filter_module>

(gdb) p ngx_modules[45]

$44 = (ngx_module_t *) 0x688020<ngx_http_not_modified_filter_module>

(gdb) p ngx_modules[48]

$45 = (ngx_module_t *) 0x7fffffffe4f8

(gdb) p ngx_modules[47]

$46 = (ngx_module_t *) 0x0

这么多模块是怎么初始化的？

是在make命令自动生成的文件ngx_modules.c中

ngx_module_t *ngx_modules[] = {

&ngx_core_module,

&ngx_errlog_module,

&ngx_conf_module,

&ngx_events_module,

&ngx_event_core_module,

&ngx_epoll_module,

&ngx_regex_module,

&ngx_http_module,

&ngx_http_core_module,

&ngx_http_log_module,

&ngx_http_upstream_module,

&ngx_http_static_module,

&ngx_http_autoindex_module,

&ngx_http_index_module,

&ngx_http_auth_basic_module,

&ngx_http_access_module,

&ngx_http_limit_conn_module,

&ngx_http_limit_req_module,

&ngx_http_geo_module,

&ngx_http_map_module,

&ngx_http_split_clients_module,

&ngx_http_referer_module,

&ngx_http_rewrite_module,

&ngx_http_proxy_module,

&ngx_http_fastcgi_module,

&ngx_http_uwsgi_module,

&ngx_http_scgi_module,

&ngx_http_memcached_module,

&ngx_http_empty_gif_module,

&ngx_http_browser_module,

&ngx_http_upstream_ip_hash_module,

&ngx_http_upstream_least_conn_module,

&ngx_http_upstream_keepalive_module,

&ngx_http_write_filter_module,

&ngx_http_header_filter_module,

&ngx_http_chunked_filter_module,

&ngx_http_range_header_filter_module,

&ngx_http_gzip_filter_module,

&ngx_http_postpone_filter_module,

&ngx_http_ssi_filter_module,

&ngx_http_charset_filter_module,

&ngx_http_userid_filter_module,

&ngx_http_headers_filter_module,

&ngx_http_copy_filter_module,

&ngx_http_range_body_filter_module,

&ngx_http_not_modified_filter_module,

NULL

};

nginx模块化

ngx_listening_s相当于pbrpc中的acceptor，用于监听网络连接请求，创建新的连接。

配置模块相当于配置文件解析模块，在pbrpc中，配置文件直接使用proto定义的。配置模块的解析函数：ngx_conf_parse，其中会依据配置的命令，调用相应cmd中的handler函数。

模块的定义如下：

struct ngx_module_s {

ngx_uint_t ctx_index;

ngx_uint_t index;

ngx_uint_t spare0;

ngx_uint_t spare1;

ngx_uint_t spare2;

ngx_uint_t spare3;

ngx_uint_t version;

void *ctx;

ngx_command_t *commands;

ngx_uint_t type;

ngx_int_t (*init_master)(ngx_log_t *log);

ngx_int_t (*init_module)(ngx_cycle_t *cycle);

ngx_int_t (*init_process)(ngx_cycle_t *cycle);

ngx_int_t (*init_thread)(ngx_cycle_t *cycle);

void (*exit_thread)(ngx_cycle_t *cycle);

void (*exit_process)(ngx_cycle_t *cycle);

void (*exit_master)(ngx_cycle_t *cycle);

uintptr_t spare_hook0;

uintptr_t spare_hook1;

uintptr_t spare_hook2;

uintptr_t spare_hook3;

uintptr_t spare_hook4;

uintptr_t spare_hook5;

uintptr_t spare_hook6;

uintptr_t spare_hook7;

};

在ngx_spawn_process

中使用了folk的系统调用，子进程返回后调用了ngx_worker_process_cycle。

ngx_process_events_and_timers是事件处理函数。

struct ngx_listening_s {

ngx_socket_t fd;

struct sockaddr *sockaddr;

socklen_t socklen; /* size of sockaddr */

size_t addr_text_max_len;

ngx_str_t addr_text;

int type;

int backlog;

int rcvbuf;

int sndbuf;

#if (NGX_HAVE_KEEPALIVE_TUNABLE)

int keepidle;

int keepintvl;

int keepcnt;

#endif

/* handler of accepted connection */

ngx_connection_handler_pt handler;

void *servers; /* array of ngx_http_in_addr_t, for example */

ngx_log_t log;

ngx_log_t *logp;

size_t pool_size;

/* should be here because of the AcceptEx() preread */

size_t post_accept_buffer_size;

/* should be here because of the deferred accept */

ngx_msec_t post_accept_timeout;

ngx_listening_t *previous;

ngx_connection_t *connection;

unsigned open:1;

unsigned remain:1;

unsigned ignore:1;

unsigned bound:1; /* already bound */

unsigned inherited:1; /* inherited from previous process */

unsigned nonblocking_accept:1;

unsigned listen:1;

unsigned nonblocking:1;

unsigned shared:1; /* shared between threads or processes */

unsigned addr_ntop:1;

#if (NGX_HAVE_INET6 && defined IPV6_V6ONLY)

unsigned ipv6only:1;

#endif

unsigned keepalive:2;

#if (NGX_HAVE_DEFERRED_ACCEPT)

unsigned deferred_accept:1;

unsigned delete_deferred:1;

unsigned add_deferred:1;

#ifdef SO_ACCEPTFILTER

char *accept_filter;

#endif

#if (NGX_HAVE_SETFIB)

int setfib;

#endif

#if (NGX_HAVE_TCP_FASTOPEN)

int fastopen;

#endif

};

为什么需要性能链表？多个监听端口

Ngx_connection_s相当于Tcp_connection

struct ngx_connection_s {

void *data;

ngx_event_t *read;

ngx_event_t *write;

ngx_socket_t fd;

ngx_recv_pt recv;

ngx_send_pt send;

ngx_recv_chain_pt recv_chain;

ngx_send_chain_pt send_chain;

ngx_listening_t *listening;

off_t sent;

ngx_log_t *log;

ngx_pool_t *pool;

struct sockaddr *sockaddr;

socklen_t socklen;

ngx_str_t addr_text;

ngx_str_t proxy_protocol_addr;

#if (NGX_SSL)

ngx_ssl_connection_t *ssl;

#endif

struct sockaddr *local_sockaddr;

socklen_t local_socklen;

ngx_buf_t *buffer;

ngx_queue_t queue;

ngx_atomic_uint_t number;

ngx_uint_t requests;

unsigned buffered:8;

unsigned log_error:3; /* ngx_connection_log_error_e */

unsigned unexpected_eof:1;

unsigned timedout:1;

unsigned error:1;

unsigned destroyed:1;

unsigned idle:1;

unsigned reusable:1;

unsigned close:1;

unsigned sendfile:1;

unsigned sndlowat:1;

unsigned tcp_nodelay:2; /* ngx_connection_tcp_nodelay_e */

unsigned tcp_nopush:2; /* ngx_connection_tcp_nopush_e */

unsigned need_last_buf:1;

#if (NGX_HAVE_IOCP)

unsigned accept_context_updated:1;

#endif

#if (NGX_HAVE_AIO_SENDFILE)

unsigned aio_sendfile:1;

unsigned busy_count:2;

ngx_buf_t *busy_sendfile;

#endif

#if (NGX_THREADS)

ngx_atomic_t lock;

#endif

};

参考：

http://blog.youkuaiyun.com/livelylittlefish/article/details/6571497