socket-event(8) System Manager's Manual socket-event(8)NAME
socket - event signalling that a socket connection has been made
SYNOPSIS
socket PROTO=PROTO PORT=PORT ADDR=ADDR
socket PROTO=PROTO PATH=PATH
DESCRIPTION
The socket event is generated by the upstart-socket-bridge(8) daemon when a socket connection is made whose details match the socket event
condition and environment specified in a jobs start on or stop on stanza.
When an incoming connection is detected, the file descriptor representing the socket is passed to the job in question to allow it to
accept(2) the connection. Additionally, the environment variable UPSTART_JOB will contain the name of the event ("socket") and the environ-
ment variable UPSTART_FDS will contain the number of the file descriptor corresponding to the listening socket.
EXAMPLES
Internet socket
Start web server when first client connects from localhost:
start on socket PROTO=inet PORT=80 ADDR=127.0.0.1
Local socket
start on socket PROTO=unix PATH=/var/run/.s.pgsql.1234
Abstract socket
start on socket PROTO=unix PATH=@/at/upstart/example
AUTHOR
Written by Scott James Remnant <scott@netsplit.com>
Manual page written by James Hunt <james.hunt@ubuntu.com>
BUGS
Report bugs at <https://launchpad.net/upstart/+bugs>
COPYRIGHT
Copyright (C) 2011 Canonical Ltd.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
LAR PURPOSE.
SEE ALSO init(5)init(8)socket(2)socket(7)upstart-socket-bridge(8)upstart 2011-03-08 socket-event(8)
Check Out this Related Man Page
accept(2) System Calls Manual accept(2)Name
accept - accept a connection on a socket
Syntax
#include <sys/types.h>
#include <sys/socket.h>
accept(s, addr, addrlen)
int ns, s;
struct sockaddr *addr;
int *addrlen;
Description
The system call accepts a connection on a socket. The argument s is a socket that has been created with the call, bound to an address with
the call and is listening for connections after a call. The system call extracts the first connection on the queue of pending connections,
creates a new socket with the same properties of s and allocates a new file descriptor, ns, for the socket. If no pending connections are
present on the queue, and the socket is not marked as nonblocking, blocks the caller until a connection is present. If the socket is
marked nonblocking and no pending connections are present on the queue, returns an error. The accepted socket, ns, cannot be used to
accept more connections. The original socket s remains open.
The argument addr is a result parameter that is filled in with the address of the connecting entity, as known to the communications layer.
The exact format of the addr parameter is determined by the domain in which the communication is occurring. The addrlen is a value-result
parameter; it should initially contain the amount of space pointed to by addr. On return, addr contains the actual length in bytes of the
address returned. This call is used with connection-based socket types, currently with SOCK_STREAM.
You can use the call for the purposes of doing an call by selecting the socket for reading.
Return Values
The call returns -1 on error. If the call succeeds, it returns a non-negative integer which is a descriptor for the accepted socket.
Diagnostics
The call fails if:
[EBADF] The descriptor is invalid.
[ENOTSOCK] The descriptor references a file, not a socket.
[EOPNOTSUPP] The referenced socket is not of type SOCK_STREAM.
[EFAULT] The addr parameter is not in a writable part of the user address space.
[EWOULDBLOCK] The socket is marked nonblocking and no connections are present to be accepted.
See Alsobind(2), connect(2), listen(2), select(2), socket(2)accept(2)