view src/os/unix/ngx_process.h @ 8106:8852f39311de

Fixed segfault when switching off master process during upgrade. Binary upgrades are not supported without master process, but it is, however, possible, that nginx running with master process is asked to upgrade binary, and the configuration file as available on disk at this time includes "master_process off;". If this happens, listening sockets inherited from the previous binary will have ls[i].previous set. But the old cycle on initial process startup, including startup after binary upgrade, is destroyed by ngx_init_cycle() once configuration parsing is complete. As a result, an attempt to dereference ls[i].previous in ngx_event_process_init() accesses already freed memory. Fix is to avoid looking into ls[i].previous if the old cycle is already freed. With this change it is also no longer needed to clear ls[i].previous in worker processes, so the relevant code was removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Nov 2022 23:48:53 +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_ */