Nginx Source (4) main process

Connect to the above.

Nginx in a single process run up in the console, read core/nginx.c in the main method, before the initialization of the code, first not carefully read, easy to fall into the delicate ring. Directly find the definition of ngx_single_process_cycle, in os/unix/ngx_process_cycle.c.

Add the following code to the first for loop:

  for  (i =  0 ; ngx_modules[i]; i++) { char  * p = NULL;  if  (Ngx_modules[i]->commands! = NULL) {p = ngx_modules[i]->commands->name.data; }  if  (ngx_modules[i]->init_process) { if  (Ngx_modules[i]->init_process (c ycle) = = Ngx_error) {/* fatal */  exit  ( 2 );  printf  ( "[ngx_process_cycle] module ctx_index=%d index=%d name=%s init process\n" , n Gx_modules[i]->ctx_index, Ngx_modules[i]->index, p); }  else  { printf  ( "[ngx_process_cycle] module ctx_index=%d index=%d Name=%s\n ", Ngx_modules[i]->ctx_index, Ngx_modules[i]->index, p); }}  printf  ( "[ngx_process_cycle] for ngx_modules init done\n" ); 

The function is to print which modules and related indexes and names are in the current nginx.

In the second for loop, the main is the Ngx_process_events method, find this is a macro, and then this macro is a global variable, because we load the Epoll module, so in event/modules/ngx_epoll_module.c
Code found in:

ngx_event_actions = ngx_epoll_module_ctx.actions;

The discovery Ngx_process_events method is actually the Ngx_epoll_process_events method in the actions in the Ngx_epoll_module_ctx module. In this method, find the place where the Epoll_wait method is called, plus the following code:

printf("[ngx_epoll_module] epoll wait\n");    events = epoll_wait(ep, event_list, nevents, timer);    printf("[ngx_epoll_module] epoll wait ---\n");

Re-make run result:

[main] to start ngx_single_process_cycle
[Ngx_process_cycle] Module ctx_index=0 index=0 Name=daemon
[Ngx_process_cycle] Module ctx_index=0 index=1 name=error_log
[Ngx_process_cycle] Module ctx_index=0 index=2 name=include
[Ngx_process_cycle] Module ctx_index=0 index=3 name=events
[Ngx_process_cycle] Module ctx_index=0 index=4 name=connections init process
[Ngx_process_cycle] Module ctx_index=1 index=5 Name=rtsig_signo
[Ngx_process_cycle] Module ctx_index=2 index=6 name=epoll_events
[Ngx_process_cycle] Module ctx_index=0 index=7 name=http
[Ngx_process_cycle] Module ctx_index=0 index=8 name=server
[Ngx_process_cycle] Module ctx_index=1 index=9 name=log_format
[Ngx_process_cycle] Module ctx_index=2 index=10 name= (NULL)
[Ngx_process_cycle] Module ctx_index=3 index=11 name=index
[Ngx_process_cycle] Module ctx_index=4 index=12 name=allow
[Ngx_process_cycle] Module ctx_index=5 index=13 name=rewrite
[Ngx_process_cycle] Module ctx_index=6 index=14 name=proxy_pass
[Ngx_process_cycle] Module ctx_index=7 index=15 name= (NULL)
[Ngx_process_cycle] Module ctx_index=8 index=16 name= (NULL)
[Ngx_process_cycle] Module ctx_index=9 index=17 name= (NULL)
[Ngx_process_cycle] Module ctx_index=10 index=18 name= (NULL)
[Ngx_process_cycle] Module ctx_index=11 index=19 name=gzip
[Ngx_process_cycle] Module ctx_index=12 index=20 name=charset_map
[Ngx_process_cycle] Module ctx_index=13 index=21 Name=userid
[Ngx_process_cycle] Module ctx_index=14 index=22 name=expires
[Ngx_process_cycle] Module ctx_index=15 index=23 name=output_buffers
[Ngx_process_cycle] Module ctx_index=16 index=24 name= (NULL)
[Ngx_process_cycle] Module ctx_index=17 index=25 name= (NULL)
[Ngx_process_cycle] for ngx_modules init done
[Ngx_epoll_module] Epoll wait
^c[ngx_epoll_module] Epoll wait-

There are 25 modules found, only the Connections module has the Init_process method, and some modules name is empty. Finally, the program entered into the Epoll module, blocking at the epoll_wait call, CTRL + C launched after the execution of the following print statements.

Here can take a closer look at the Nginx definition of the module, see the code when it is easy to find the actual type of nginx in the _t end, and if the type is defined by the structure of the actual type is _s end, nginx_module_s is defined in the Core/ngx_ In the Conf_file.h file:

struct ngx_module_s {    ngx_uint_t       ctx_index;    ngx_uint_t       index;    void            *ctx;    ngx_command_t   *commands;    ngx_uint_t       type;    ngx_int_t      (*init_module)(ngx_cycle_t *cycle);    ngx_int_t      (*init_process)(ngx_cycle_t *cycle);#if 0    ngx_int_t      (*init_thread)(ngx_cycle_t *cycle);#endif};

There are two index numbers, as well as commands and 3 functions, and what they mean to use later.

There are two other structural bodies ngx_event_module_t and ngx_event_actions_t; The latter is a member of the former, the former is the Nginx event module, but the abstract, specific to a platform will have a different type, here is Epoll.
ngx_event_module_t as follows:

typedef struct {    ngx_str_t              *name;    void                 *(*create_conf*cycle);    char                 *(*init_conf*cycle*conf);    ngx_event_actions_t     actions;} ngx_event_module_t;

Epoll examples are as follows:

ngx_event_module_t Ngx_epoll_module_ctx = {&epoll_name, ngx_epoll_create_conf,/ * Create configuration * /Ngx_epoll_init_conf,/ * INIT configuration * /{ngx_epoll_add_event,/ * Add an event * /Ngx_epoll_del_event,/ * Delete an event * /Ngx_epoll_add_event,/ * Enable an event * /Ngx_epoll_del_event,/ * Disable an event * /Ngx_epoll_add_connection,/ * Add an connection * /Ngx_epoll_del_connection,/ * Delete an connection * /NULL,/ * Process the changes * /Ngx_epoll_process_events,/ * Process the events * /Ngx_epoll_init,/ * Init the events * *Ngx_epoll_done,/* Done the events * /}};

Just as the actions members in ngx_event_module_t are defined in NGX_EPOLL_MODULE_CTX as Epoll related functions, the preceding ngx_process_events is concatenated by the following two lines of code:
In Event/ngx_event.h

#define ngx_process_events   ngx_event_actions.process_events

In event/modules/ngx_epoll_module.c

   ngx_event_actions = ngx_epoll_module_ctx.actions;

Ngx_event_actions is defined as a global variable in event/ngx_event.c:

ngx_event_actions_t               ngx_event_actions;

Next look at the use of Epoll in Nginx.

To be Continued ...

The above describes the Nginx source (4) main process, including the aspects of the content, I hope that the PHP tutorial interested in a friend helpful.

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