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       imclient  -  (library)  authenticating  callback interface to IMAP/IMSP


       #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, intflags);
       void imclient_clearflags (struct imclient *imclient, intflags);
       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 *
       void imclient_processoneevent (struct imclient *imclient);
       int imclient_authenticate (struct imclient *imclient, struct
       sasl_client **availmech, const char *service, const char *user, int
       int imclient_havetls ();
       int imclient_starttls (struct imclient *imclient, char *cert_file, char
       *key_file, char *CAfile, char *CApath);


       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.

            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.

            Closes and frees the imclient connection.

            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+

            Clears the flags specified by the flags argument on the imclient

            Returns a  char * pointer to the name of the server connected to
            by imclient.

            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 over write  the text of
            untagged data.

            Sends a new command to the imclient connection.  finishproc 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_authenticate() 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
               %% for %
               %a for an IMAP atom
               %s for an astring (which will be quoted or literalized as
               %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)

            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

            Processes one input or output event on the imclient connection.

            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
            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.

            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.

            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.


       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[] = {
       struct imclient *imclient;
       char server[] = "" ;
       char port[] = "imap";

       void fatal(char* message, int rc) {
           fprintf(stderr, "fatal error: %s\n", message);

       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) {

       main() {
           char* capability_string;
           int nc;

           if (imclient_connect(&imclient, server, port)) {
                 "error: Couldn't connect to %s %s\n",
                 server, port);

           if (imclient_authenticate(imclient, login_sasl_client, "imap"
                            /* service */,
                            NULL /* user */, SASL_PROT_ANY)) {

           imclient_addcallback(imclient, "CAPABILITY",

           nc = 1;

           imclient_send(imclient, end_command,
                   (void*) &nc, "CAPABILITY");

           while(nc > 0) {

           if (strstr("LITERAL+", capability_string)) {
            imclient_setflags(imclient, IMCLIENT_CONN_NONSYNCLITERAL);

           imclient_send(imclient, NULL, NULL, "LOGOUT");

           printf("capability text is: %s\n", capability_string);



       No known bugs.


       cyradm, imapd, imspd, RFC2033 (IMAP LITERAL+ extension), RFC2060
       (IMAP4rev1 specification), and select(2)


       IMAP, ACAP, IMSP, Kerberos, Authentication


       Copyright 1997-2002, Carnegie Mellon University.  All Rights Reserved.

       See the source distribution for copying information.