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view src/os/unix/ngx_process.h @ 9270:3d455e37abf8

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Core: PID file writing synchronization. Now, ngx_daemon() does not call exit() in the parent process immediately, but instead waits for the child process to signal it actually started (and wrote the PID file if configured to). This ensures that the PID file already exists when the parent process exits. To make sure that signal handlers won't cause unexpected logging in the parent process if the child process dies (for example, due to errors when writing the PID file), ngx_init_signals() is moved to the child process. This resolves "PID file ... not readable (yet?) after start" and "Failed to parse PID from file..." errors as observed with systemd. Note that the errors observed are considered to be a bug in systemd, which isn't able to work properly with traditional Unix daemons. Still, the workaround is implemented to make sure there will be no OS vendor patches trying to address this.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 13 May 2024 06:13:22 +0300
parents 8b84d60ef13d
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_PROCESS_H_INCLUDED_
#define _NGX_PROCESS_H_INCLUDED_


#include <ngx_setaffinity.h>
#include <ngx_setproctitle.h>


typedef pid_t       ngx_pid_t;

#define NGX_INVALID_PID  -1

typedef void (*ngx_spawn_proc_pt) (ngx_cycle_t *cycle, void *data);

typedef struct {
    ngx_pid_t           pid;
    int                 status;
    ngx_socket_t        channel[2];

    ngx_spawn_proc_pt   proc;
    void               *data;
    char               *name;

    unsigned            respawn:1;
    unsigned            just_spawn:1;
    unsigned            detached:1;
    unsigned            exiting:1;
    unsigned            exited:1;
} ngx_process_t;


typedef struct {
    char         *path;
    char         *name;
    char *const  *argv;
    char *const  *envp;
} ngx_exec_ctx_t;


#define NGX_MAX_PROCESSES         1024

#define NGX_PROCESS_NORESPAWN     -1
#define NGX_PROCESS_JUST_SPAWN    -2
#define NGX_PROCESS_RESPAWN       -3
#define NGX_PROCESS_JUST_RESPAWN  -4
#define NGX_PROCESS_DETACHED      -5


#define ngx_getpid   getpid
#define ngx_getppid  getppid

#ifndef ngx_log_pid
#define ngx_log_pid  ngx_pid
#endif


ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle,
    ngx_spawn_proc_pt proc, void *data, char *name, ngx_int_t respawn);
ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx);
ngx_int_t ngx_init_signals(ngx_log_t *log);
void ngx_debug_point(void);


#if (NGX_HAVE_SCHED_YIELD)
#define ngx_sched_yield()  sched_yield()
#else
#define ngx_sched_yield()  usleep(1)
#endif


extern int            ngx_argc;
extern char         **ngx_argv;
extern char         **ngx_os_argv;

extern ngx_pid_t      ngx_pid;
extern ngx_pid_t      ngx_parent;
extern ngx_socket_t   ngx_channel;
extern ngx_int_t      ngx_process_slot;
extern ngx_int_t      ngx_last_process;
extern ngx_process_t  ngx_processes[NGX_MAX_PROCESSES];


#endif /* _NGX_PROCESS_H_INCLUDED_ */