1 /* $NetBSD: master_proto.h,v 1.3 2025/02/25 19:15:46 christos Exp $ */ 2 3 /*++ 4 /* NAME 5 /* master_proto 3h 6 /* SUMMARY 7 /* master process protocol 8 /* SYNOPSIS 9 /* #include <master_proto.h> 10 /* DESCRIPTION 11 /* .nf 12 13 /* 14 * Transport names. The master passes the transport name on the command 15 * line, and thus the name is part of the master to child protocol. 16 */ 17 #define MASTER_XPORT_NAME_UNIX "unix" /* local IPC */ 18 #define MASTER_XPORT_NAME_FIFO "fifo" /* local IPC */ 19 #define MASTER_XPORT_NAME_INET "inet" /* non-local IPC */ 20 #define MASTER_XPORT_NAME_PASS "pass" /* local IPC */ 21 #define MASTER_XPORT_NAME_UXDG "unix-dgram" /* local IPC */ 22 23 /* 24 * Format of a status message sent by a child process to the process 25 * manager. Since this is between processes on the same machine we need not 26 * worry about byte order and word length. 27 */ 28 typedef struct MASTER_STATUS { 29 int pid; /* process ID */ 30 unsigned gen; /* child generation number */ 31 int avail; /* availability */ 32 } MASTER_STATUS; 33 34 #define MASTER_GEN_NAME "GENERATION" /* passed via environment */ 35 36 #define MASTER_STAT_TAKEN 0 /* this one is occupied */ 37 #define MASTER_STAT_AVAIL 1 /* this process is idle */ 38 39 extern int master_notify(int, unsigned, int); /* encapsulate status msg */ 40 41 /* 42 * File descriptors inherited from the master process. The flow control pipe 43 * is read by receive processes and is written to by send processes. If 44 * receive processes get too far ahead they will pause for a brief moment. 45 */ 46 #define MASTER_FLOW_READ 3 47 #define MASTER_FLOW_WRITE 4 48 49 /* 50 * File descriptors inherited from the master process. All processes that 51 * provide a given service share the same status file descriptor, and listen 52 * on the same service socket(s). The kernel decides what process gets the 53 * next connection. Usually the number of listening processes is small, so 54 * one connection will not cause a "thundering herd" effect. When no process 55 * listens on a given socket, the master process will. MASTER_LISTEN_FD is 56 * actually the lowest-numbered descriptor of a sequence of descriptors to 57 * listen on. 58 */ 59 #define MASTER_STATUS_FD 5 /* shared channel to parent */ 60 #define MASTER_LISTEN_FD 6 /* accept connections here */ 61 62 /* LICENSE 63 /* .ad 64 /* .fi 65 /* The Secure Mailer license must be distributed with this software. 66 /* AUTHOR(S) 67 /* Wietse Venema 68 /* IBM T.J. Watson Research 69 /* P.O. Box 704 70 /* Yorktown Heights, NY 10598, USA 71 /* 72 /* Wietse Venema 73 /* Google, Inc. 74 /* 111 8th Avenue 75 /* New York, NY 10011, USA 76 /*--*/ 77