SRV(3) 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 bul-
letin board on which processes may post open file descrip-
tors 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/myserv 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", 1, 0666);
sprint(buf, "%d", p[0]);
write(fd, buf, strlen(buf));
close(fd);
close(p[0]);
write(p[1], "hello", 5);
At this point, any process may open and read /srv/namedpipe
to receive the hello string. Data written to /srv/namedpipe
will be received by executing
read(p[1], buf, sizeof buf);
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SRV(3) SRV(3)
in the above process.
SOURCE
/sys/src/9/port/devsrv.c
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