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.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_FREEBSD_H_INCLUDED_
#define _NGX_FREEBSD_H_INCLUDED_


void ngx_debug_init(void);
ngx_chain_t *ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in,
    off_t limit);

extern int         ngx_freebsd_kern_osreldate;
extern int         ngx_freebsd_hw_ncpu;
extern u_long      ngx_freebsd_net_inet_tcp_sendspace;

extern ngx_uint_t  ngx_freebsd_sendfile_nbytes_bug;
extern ngx_uint_t  ngx_freebsd_use_tcp_nopush;
extern ngx_uint_t  ngx_debug_malloc;


#endif /* _NGX_FREEBSD_H_INCLUDED_ */