Provided by: cyrus-dev_3.0.13-5_amd64 
NAME
imclient - Cyrus IMAP documentation
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 (*finishproc)(),
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);
int imclient_havetls ();
int imclient_starttls (struct imclient *imclient, char *cert_file,
char *key_file, char *CAfile, char *CApath);
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.la.
All of the imclient functions begin with the prefix imclient and take 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 successful, it returns 0 and sets the
imclient argument to a pointer to an imclient struct. The imclient struct
represents the current connection, flags, and callbacks. 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 connection. 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 keyword. 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_authenticate() on the connection. The
callback function may overwrite the text of untagged data.
imclient_send()
Sends a new command to the imclient connection. finishproc and finishrock are the
function and rock called when the command completes. functionproc may be a null
pointer, in which case no callback is made. The callback function may not call the
functions imclient_close(), imclient_send(), imclient_eof(),
imclient_processoneevent(), or imclient_authenticate() on the connection. The
argument fmt is a printf(3) 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 literalized 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 separated 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 protection 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.
imclient_havetls()
Returns a Boolean indicating whether the imclient library was compiled with TLS
(SSL) support. If so, imclient_starttls() may be used to secure the IMAP
connection.
imclient_starttls()
Issues a STARTTLS command on an existing IMAP connection and negotiates the secure
link. The cert_file and key_file arguments specify the client certificate and
secret key to use to authenticate ourselves to the server. If client
authentication is not needed, set both of these arguments to NULL.
The CAfile and CApath arguments specify a file or directory, respectively, of CA
certificates for validating server certificates. (See
SSL_CTX_load_verify_locations(3) for details.) If both of these are NULL, the
client will be unable to validate the server's certificate, in which case the
connection may succeed but a warning will be printed to stdout.
EXAMPLES
The following code is a possible skeleton of imclient that relies on Kerberos to do
authentication. This code performs an IMAP CAPABILITY request and prints out the result.
#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\en", 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\en",
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\en", capability_string);
free(capability_string);
}
BUGS
No known bugs.
SEE ALSO
cyradm(8), imapd(8), RFC 2033 (IMAP LITERAL+ extension), RFC 2060 (IMAP4rev1
specification), and select(2)
KEYWORDS
IMAP, ACAP, IMSP, Kerberos, Authentication
AUTHOR
The Cyrus Team, Nic Bernstein (Onlight)
COPYRIGHT
1993-2017, The Cyrus Team