TH PLUMB 2
SH NAME
eplumb, plumbfree, plumbopen, plumbsend, plumbsendtext, plumblookup, plumbpack, plumbpackattr, plumbaddattr, plumbdelattr, plumbrecv, plumbunpack, plumbunpackpartial, plumbunpackattr, Plumbmsg \- plumb messages
SH SYNOPSIS
B #include <u.h>
br
B #include <libc.h>
br
B #include <plumb.h>
PP
ta \w'\fLPlumbattr* 'u
PP
B
int plumbopen(char *port, int omode)
PP
B
int plumbsend(int fd, Plumbmsg *m)
PP
B
int plumbsendtext(int fd, char *src, char *dst, char *wdir, char *data)
PP
B
void plumbfree(Plumbmsg *m)
PP
B
Plumbmsg* plumbrecv(int fd)
PP
B
char* plumbpack(Plumbmsg *m, int *np)
PP
B
Plumbmsg* plumbunpack(char *buf, int n)
PP
B
Plumbmsg* plumbunpackpartial(char *buf, int n, int *morep)
PP
B
char* plumbpackattr(Plumbattr *a)
PP
B
Plumbattr* plumbunpackattr(char *a)
PP
B
char* plumblookup(Plumbattr *a, char *name)
PP
B
Plumbattr* plumbaddattr(Plumbattr *a, Plumbattr *new)
PP
B
Plumbattr* plumbdelattr(Plumbattr *a, char *name)
PP
B
int eplumb(int key, char *port)
SH DESCRIPTION
These routines manipulate
IR plumb (6)
messages, transmitting them, receiving them, and
converting them between text and these data structures:
IP
EX
ta 6n +\w'\fLPlumbattr 'u +\w'ndata; 'u
typedef
struct Plumbmsg
{
char *src;
char *dst;
char *wdir;
char *type;
Plumbattr *attr;
int ndata;
char *data;
} Plumbmsg;
typedef
struct Plumbattr
{
char *name;
char *value;
Plumbattr *next;
} Plumbattr;
EE
PP
I Plumbopen
opens the named plumb
IR port ,
using
IR open (2)
mode
IR omode .
If
I port
begins with a slash, it is taken as a literal file name;
otherwise
I plumbopen
searches for the location of the
IR plumber (4)
service and opens the port there.
PP
For programs using the
IR event (2)
interface,
I eplumb
registers, using the given
IR key ,
receipt of messages from the named
IR port .
PP
I Plumbsend
formats and writes message
I m
to the file descriptor
IR fd ,
which will usually be the result of
B plumbopen("send",
BR OWRITE) .
I Plumbsendtext
is a simplified version for text-only messages; it assumes
B type
is
BR text ,
sets
B attr
to nil,
and sets
B ndata
to
BI strlen( data )\f1.
PP
I Plumbfree
frees all the data associated with the message
IR m ,
all the components of which must therefore have been allocated with
IR malloc (2).
PP
I Plumbrecv
returns the next message available on the file descriptor
IR fd ,
or nil for error.
PP
I Plumbpack
encodes message
I m
as a character string in the format of
IR plumb (6) ,
setting
BI * np
to the length in bytes of the string.
I Plumbunpack
does the inverse, translating the
I n
bytes of
I buf
into a
BR Plumbmsg .
PP
I Plumbunpackpartial
enables unpacking of messages that arrive in pieces.
The first call to
I plumbunpackpartial
for a given message must be sufficient to unpack the header;
subsequent calls permit unpacking messages with long data sections.
For each call,
I buf
points to the beginning of the complete message received so far, and
I n
reports the total number of bytes received for that message.
If the message is complete, the return value will be as in
IR plumbunpack .
If not, and
I morep
is not null, the return value will be
B nil
and
BR * morep
will be set to the number of bytes remaining to be read for this message to be complete
(recall that the byte count is in the header).
Those bytes should be read by the caller, placed at location
IB buf + n \f1,
and the message unpacked again.
If an error is encountered, the return value will be
B nil
and
BI * morep
will be zero.
PP
I Plumbpackattr
converts the list
I a
of
B Plumbattr
structures into a null-terminated string.
If an attribute value contains white space, quote characters, or equal signs,
the value will be quoted appropriately.
A newline character will terminate processing.
I Plumbunpackattr
converts the null-terminated string
I a
back into a list of
I Plumbattr
structures.
PP
I Plumblookup
searches the
B Plumbattr
list
I a
for an attribute with the given
I name
and returns the associated value.
The returned string is the original value, not a copy.
If the attribute has no value, the returned value will be the empty string;
if the attribute does not occur in the list at all, the value will be nil.
PP
I Plumbaddattr
appends the
I new
B Plumbattr
(which may be a list) to the attribute list
IR a
and returns the new list.
I Plumbdelattr
searches the list
I a
for the first attribute with name
I name
and deletes it from the list, returning the resulting list.
I Plumbdelattr
is a no-op if no such attribute exists.
SH SOURCE
B /sys/src/libplumb
SH SEE ALSO
IR plumb (1),
IR event (2),
IR plumber (4),
IR plumb (6)
SH DIAGNOSTICS
When appropriate, including when a
I plumbsend
fails, these routine set
IR errstr .
