IMCLIENT(3)IMCLIENT(3)NAMEimclient library - authenticating callback interface to
IMAP/IMSP servers
SYNOPSIS
#include <cyrus/imclient.h>
int imclient_connect(struct imclient **imclient, const
char *host, const char *port);
void imclient_close (struct imclient *imclient);
void imclient_setflags(struct imclient *imclient, int-
flags);
void imclient_clearflags (struct imclient *imclient, int-
flags);
char* imclient_servername (struct imclient *imclient);
void imclient_addcallback (struct imclient * imclient
,...);
void imclient_send (struct imclient *imclient, void (*fin-
ishproc)(), void *finishrock, const char *fmt, ...);
void imclient_getselectinfo (struct imclient *imclient,
int *fd, int * wanttowrite);
void imclient_processoneevent (struct imclient *imclient);
int imclient_authenticate (struct imclient *imclient,
struct sasl_client **availmech, const char *service, const
char *user, int protallowed);
DESCRIPTION
The imclient library functions are distributed with Cyrus
IMAP and IMSP. These functions are used for building
IMAP/IMSP client software. These functions handle Kerberos
authentication and can set callbacks based on the keyword
in untagged replies or based on the command tag at the end
of command replies.
Users must link with the -lcyrus switch, and must supply a
function called fatal to be called in case of any error
within libcyrus.a.
All of the imclient functions begin with the prefix
imclient and takes an argument of type struct imclient *
as the first argument which is initialized by
imclient_connect and freed by imclient_close.
See below for a description of each function.
imclient_connect()
Connects the client server to the host. If success-
ful, it returns 0 and sets the imclient argument to a
pointer to an imclient struct. The imclient struct
represents the current connection, flags, and call-
backs. On failure, the current errno is returned if a
system call failed, -1 is returned if the host name
was not found, and -2 is returned if the service
name was not found.
imclient_close()
Closes and frees the imclient connection.
imclient_setflags()
Sets the flags specified by the flags argument on the
imclient connection. Currently the only flag allowed
is IMCLIENT_CONN_NONSYNCLITERAL (this flag indicates
that the server supports non-synchronizing literals
described by the LITERAL+ extension).
imclient_clearflags()
Clears the flags specified by the flags argument on
the imclient connection.
imclient_servername()
Returns a char * pointer to the name of the server
connected to by imclient.
imclient_addcallback()
Adds an untagged data callback to the imclient con-
nection. The function imclient_addcallback takes
callbacks of the type imclient_proc_t which is
defined to be:
typedef void imclient_proc_t (struct imclient
*imclient, void *rock, struct imclient_reply
*reply);
and struct imclient_reply * is defined to be:
struct imclient_reply {
char *keyword;
long msgno;
char *text;
};
After the first argument imclient, there can be zero
or more instances of the set of keyword, flags, proc,
and rock, each adding or changing a single callback.
Each instance adds or changes the callback for key-
word. The argument, flags, specifies information
about the parsing of the untagged data. proc and
rock specify the callback function and rock to invoke
when the untagged data is received. proc may be a
null pointer, in which case no function is invoked.
The callback function may not call the functions
imclient_close(), imclient_send(), imclient_eof(),
imclient_processoneevent(), or imclient_authenti-
cate() on the connection. The callback function may
over write the text of untagged data.
imclient_send()
Sends a new command to the imclient connection. fin-
ishproc and finnishrock are the function and rock
called when the command completes. functionproc may
be a null pointer, in which case no callback is made.
The call back function may not call the functions
imclient_close(), imclient_send(), imclient_eof(),
imclient_processoneevent(), or imclient_authenti-
cate() on the connection. The argument, fmt , is a
print like specification of the command. It must not
include the tag as the tag is automatically added by
imclient_send(). The defined %-sequences are:
%% for %
%a for an IMAP atom
%s for an astring (which will be quoted or liter-
alized as needed)
%d for a decimal
%u for an unsigned decimal
%v for #astring (argument is a null-terminated
array of char * which are written as space sepa-
rated astrings)
imclient_getselectinfo()
Gets the information for calling select(2). fd is
filled in with the file descriptor to select(2) for
read. wanttowrite is filled in with a nonzero value
if select should be used for write as well.
imclient_processoneevent()
Processes one input or output event on the imclient
connection.
imclient_authenticate()
Authenticates the imclient connection using one of
the mechanisms in availmech. The argument, user, if
not NULL, specifies the user to authenticate as. If
the user is NULL, the current user is used. The
argument protallowed is a bitmask of permissible pro-
tection mechanisms.
On success, 0 is returned. On failure (i.e., "BAD"
keyboard, or no authentication mechanisms worked), 1
is returned. On extreme failure (premature "OK"), 2
is returned.
EXAMPLES
The following code is a possible skeletion of imclient
that relies on Kerberos to do authentication. This code
preforms an IMAP CAPABILITY request and prints out the
result.
struct sasl_client;
#include <cyrus/xmalloc.h> /* example uses xstrdup */
#include <cyrus/sasl.h>
#include <cyrus/imclient.h>
#include <stdio.h>
extern struct sasl_client krb_sasl_client;
struct sasl_client *login_sasl_client[] = {
&krb_sasl_client,
NULL
};
struct imclient *imclient;
char server[] = "cyrus.andrew.cmu.edu" ;
char port[] = "imap";
void fatal(char* message, int rc) {
fprintf(stderr, "fatal error: %s\n", message);
exit(rc);
}
static void callback_capability(struct imclient *imclient,
void *rock,
struct imclient_reply *reply) {
if (reply->text != NULL) {
*((char**)rock) = xstrdup( reply->text );
}
}
static void end_command (struct imclient *connection, void*
rock, struct imclient_reply *inmsg) {
(*(int*)rock)--;
}
main() {
char* capability_string;
int nc;
if (imclient_connect(&imclient, server, port)) {
fprintf(stderr,
"error: Couldn't connect to %s %s\n",
server, port);
exit(1);
}
if (imclient_authenticate(imclient, login_sasl_client, "imap"
/* service */,
NULL /* user */, SASL_PROT_ANY)) {
exit(1);
}
imclient_addcallback(imclient, "CAPABILITY",
CALLBACK_NOLITERAL,
callback_capability,
&capability_string,
NULL);
nc = 1;
imclient_send(imclient, end_command,
(void*) &nc, "CAPABILITY");
while(nc > 0) {
imclient_processoneevent(imclient);
}
if (strstr("LITERAL+", capability_string)) {
imclient_setflags(imclient, IMCLIENT_CONN_NONSYNCLITERAL);
}
imclient_send(imclient, NULL, NULL, "LOGOUT");
imclient_close(imclient);
printf("capability text is: %s\n", capability_string);
free(capability_string);
}
BUGS
No known bugs.
SEE ALSO
cyradm, imapd, imspd, RFC2033 (IMAP LITERAL+ extension),
RFC2060 (IMAP4rev1 specification), and select(2)KEYWORDS
IMAP, ACAP, IMSP, Kerberos, Authentication
COPYRIGHT
Copyright 1997-2002, Carnegie Mellon University. All
Rights Reserved.
See the source distribution for copying information.
9 August 1997 IMCLIENT(3)
