Nginx源码阅读（模块）

每个nginx模块，都是一个ngx_module_t类型的变量。根据ngx_module_t的type，所有nginx模块可以分为5种类型：

基本数据结构的定义

struct ngx_module_s {
    ngx_uint_t            ctx_index; // ctx_index表示当前模块在一类模块（type相同）中的序号
    ngx_uint_t            index; // index表示当前模块在所有模块中的序号

    char                 *name;

    ngx_uint_t            spare0;
    ngx_uint_t            spare1;

    ngx_uint_t            version;
    const char           *signature;

    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;
};

// 核心模块的ctx指向的数据结构 
typedef struct {
    ngx_str_t             name;
    void               *(*create_conf)(ngx_cycle_t *cycle);
    char               *(*init_conf)(ngx_cycle_t *cycle, void *conf);
} ngx_core_module_t;

// 事件模块的ctx指向的数据结构 
typedef struct {
    ngx_str_t              *name;

    void                 *(*create_conf)(ngx_cycle_t *cycle);
    char                 *(*init_conf)(ngx_cycle_t *cycle, void *conf);

    ngx_event_actions_t     actions;
} ngx_event_module_t;

// http模块的ctx指向的数据结构
typedef struct {
    ngx_int_t   (*preconfiguration)(ngx_conf_t *cf);
    ngx_int_t   (*postconfiguration)(ngx_conf_t *cf);

    void       *(*create_main_conf)(ngx_conf_t *cf);
    char       *(*init_main_conf)(ngx_conf_t *cf, void *conf);

    void       *(*create_srv_conf)(ngx_conf_t *cf);
    char       *(*merge_srv_conf)(ngx_conf_t *cf, void *prev, void *conf);

    void       *(*create_loc_conf)(ngx_conf_t *cf);
    char       *(*merge_loc_conf)(ngx_conf_t *cf, void *prev, void *conf);
} ngx_http_module_t;

// mail模块的ctx指向的数据结构
typedef struct {
    ngx_mail_protocol_t        *protocol;

    void                       *(*create_main_conf)(ngx_conf_t *cf);
    char                       *(*init_main_conf)(ngx_conf_t *cf, void *conf);

    void                       *(*create_srv_conf)(ngx_conf_t *cf);
    char                       *(*merge_srv_conf)(ngx_conf_t *cf, void *prev,
                                                  void *conf);
} ngx_mail_module_t;

struct ngx_command_s {
    ngx_str_t             name; // 命令名
    ngx_uint_t            type; // 命令类型
    char               *(*set)(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
    ngx_uint_t            conf;
    ngx_uint_t            offset;
    void                 *post;
};

6个核心模块的定义

// 定义核心模块ngx_core_module
static ngx_command_t  ngx_core_commands[] = {...};

static ngx_core_module_t  ngx_core_module_ctx = {
    ngx_string("core"),
    ngx_core_module_create_conf,
    ngx_core_module_init_conf
};

ngx_module_t  ngx_core_module = {
    NGX_MODULE_V1,
    &ngx_core_module_ctx,                  /* module context */
    ngx_core_commands,                     /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


// 定义核心模块ngx_errlog_module
static ngx_command_t  ngx_errlog_commands[] = {...};

static ngx_core_module_t  ngx_errlog_module_ctx = {
    ngx_string("errlog"),
    NULL,
    NULL
};

ngx_module_t  ngx_errlog_module = {
    NGX_MODULE_V1,
    &ngx_errlog_module_ctx,                /* module context */
    ngx_errlog_commands,                   /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


// 定义核心模块ngx_events_module
static ngx_command_t  ngx_events_commands[] = {...};

static ngx_core_module_t  ngx_events_module_ctx = {
    ngx_string("events"),
    NULL,
    ngx_event_init_conf
};

ngx_module_t  ngx_events_module = {
    NGX_MODULE_V1,
    &ngx_events_module_ctx,                /* module context */
    ngx_events_commands,                   /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


// 定义核心模块ngx_openssl_module
static ngx_command_t  ngx_openssl_commands[] = {...};

static ngx_core_module_t  ngx_openssl_module_ctx = {
    ngx_string("openssl"),
    ngx_openssl_create_conf,
    NULL
};

ngx_module_t  ngx_openssl_module = {
    NGX_MODULE_V1,
    &ngx_openssl_module_ctx,               /* module context */
    ngx_openssl_commands,                  /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    ngx_openssl_exit,                      /* exit master */
    NGX_MODULE_V1_PADDING
};


// 定义核心模块ngx_http_module
static ngx_command_t  ngx_http_commands[] = {...};

static ngx_core_module_t  ngx_http_module_ctx = {
    ngx_string("http"),
    NULL,
    NULL
};

ngx_module_t  ngx_http_module = {
    NGX_MODULE_V1,
    &ngx_http_module_ctx,                  /* module context */
    ngx_http_commands,                     /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


// 定义核心模块ngx_mail_module 
static ngx_command_t  ngx_mail_commands[] = {...};

static ngx_core_module_t  ngx_mail_module_ctx = {
    ngx_string("mail"),
    NULL,
    NULL
};

ngx_module_t  ngx_mail_module = {
    NGX_MODULE_V1,
    &ngx_mail_module_ctx,                  /* module context */
    ngx_mail_commands,                     /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
}; 

1个配置模块的定义

// 定义配置模块ngx_conf_module，其中ctx为空
static ngx_command_t  ngx_conf_commands[] = {...};

ngx_module_t  ngx_conf_module = {
    NGX_MODULE_V1,
    NULL,                                  /* module context */
    ngx_conf_commands,                     /* module directives */
    NGX_CONF_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    ngx_conf_flush_files,                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

事件模块的定义

// 定义事件模块ngx_event_core_module
static ngx_command_t  ngx_event_core_commands[] = {...};

ngx_event_module_t  ngx_event_core_module_ctx = {
    &event_core_name,
    ngx_event_core_create_conf,            /* create configuration */
    ngx_event_core_init_conf,              /* init configuration */

    { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }
};

ngx_module_t  ngx_event_core_module = {
    NGX_MODULE_V1,
    &ngx_event_core_module_ctx,            /* module context */
    ngx_event_core_commands,               /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    NULL,                                  /* init master */
    ngx_event_module_init,                 /* init module */
    ngx_event_process_init,                /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

http模块的定义

// 定义http模块ngx_http_core_module
static ngx_command_t  ngx_http_core_commands[] = {...}

static ngx_http_module_t  ngx_http_core_module_ctx = {
    ngx_http_core_preconfiguration,        /* preconfiguration */
    ngx_http_core_postconfiguration,       /* postconfiguration */

    ngx_http_core_create_main_conf,        /* create main configuration */
    ngx_http_core_init_main_conf,          /* init main configuration */

    ngx_http_core_create_srv_conf,         /* create server configuration */
    ngx_http_core_merge_srv_conf,          /* merge server configuration */

    ngx_http_core_create_loc_conf,         /* create location configuration */
    ngx_http_core_merge_loc_conf           /* merge location configuration */
};

ngx_module_t  ngx_http_core_module = {
    NGX_MODULE_V1,
    &ngx_http_core_module_ctx,             /* module context */
    ngx_http_core_commands,                /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

mail模块的定义

// 定义mail模块ngx_mail_core_module
static ngx_command_t  ngx_mail_core_commands[] = {...};

static ngx_mail_module_t  ngx_mail_core_module_ctx = {
    NULL,                                  /* protocol */

    ngx_mail_core_create_main_conf,        /* create main configuration */
    NULL,                                  /* init main configuration */

    ngx_mail_core_create_srv_conf,         /* create server configuration */
    ngx_mail_core_merge_srv_conf           /* merge server configuration */
};

ngx_module_t  ngx_mail_core_module = {
    NGX_MODULE_V1,
    &ngx_mail_core_module_ctx,             /* module context */
    ngx_mail_core_commands,                /* module directives */
    NGX_MAIL_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};

图解