term% cat index.txt SRV(3) Library Functions Manual SRV(3)
NAME
srv - server registry
SYNOPSIS
bind #s /srv
#s/service1
#s/service2
...
DESCRIPTION
The srv device provides a one-level directory holding already-open
channels to services. In effect, srv is a bulletin board on which pro‐
cesses may post open file descriptors to make them available to other
processes.
To install a channel, create a new file such as /srv/myserv and then
write a text string (suitable for strtoul; see atof(2)) giving the file
descriptor number of an open file. Any process may then open /srv/my‐
serv to acquire another reference to the open file that was registered.
An entry in srv holds a reference to the associated file even if no
process has the file open. Removing the file from /srv releases that
reference.
It is an error to write more than one number into a server file, or to
create a file with a name that is already being used.
EXAMPLE
To drop one end of a pipe into /srv, that is, to create a named pipe:
int fd, p[2];
char buf[32];
pipe(p);
fd = create("/srv/namedpipe", OWRITE, 0666);
fprint(fd, "%d", p[0]);
close(fd);
close(p[0]);
fprint(p[1], "hello");
At this point, any process may open and read /srv/namedpipe to receive
the hello string. Data written to /srv/namedpipe can be received by
executing
read(p[1], buf, sizeof buf);
in the above process.
SOURCE
/sys/src/9/port/devsrv.c
SRV(3)