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       auth_generic - Generic authentication request


           #include <courierauth.h>

       int rc=auth_generic(const char *service, const char *authtype,
                           const char *authdata,
                           int (*callback_func) (struct authinfo *, void *),
                           void *callback_arg);


       auth_generic processes a generic authentication request. You do not
       want to use this function. You really want to use auth_login(3)[1].
       service specifies which so-called "service" is being authenticated;
       like “imap” or “pop3”.  service may or may not be used by the Courier
       authentication library´s configured back-end module.

       authtype specifies the format of the authentication request. Three
       authentication formats are defined in courierauth.h:


           authdata contains the following string: “userid\npassword\n”. That
           is, the userid being authenticated, an ASCII newline character, the
           password, and a second newline character.

           This format is used with CRAM-MD5 or CRAM-SHA1.  authdata contains
           the following string: “challenge\nresponse\n”.  challenge is the
           base64-encoded challenge, which is followed by an ASCII newline
           character.  response is a base64-encoded string that´s followed by
           a second newline character. The base64-encoded string consists of
           the responding userid, a space character, then the response to the
           challenge expressed as hexadecimal digits.


       callback_func will be invoked if auth_generic succeeds, and
       callback_func´s return value becomes the return value from auth_generic
       (which should be 0, by convention).  callback_func will not be invoked
       if an error occurs, which is reported by a non-zero return value from
       auth_generic. By convention, a positive return value indicates an
       internal, temporary failure, such as the authentication daemon process
       not running; a negative return value indicates that this request was
       processed, but it failed.

       The second argument to callback_func will be callback_arg, which is not
       interpreted by this function in any way. The first argument will be a
       pointer to the following structure:

       Example 1. struct authinfo

           struct authinfo {
                const char *sysusername;
                const uid_t *sysuserid;
                gid_t sysgroupid;
                const char *homedir;

                const char *address;
                const char *fullname;
                const char *maildir;
                const char *quota;
                const char *passwd;
                const char *clearpasswd;

                const char *options;

                } ;

       Description of the above fields:

           The authenticated login ID.

           The authenticated account´s userid and groupid can be looked up in
           the password file using address. If this field is NULL, obtain the
           userid and the groupid from sysuserid and sysgroupid.


           sysuserid may be NULL if sysusername is initialized, otherwise it´s
           a pointer to the account´s numeric userid.

           Account´s numeric groupid.  sysgroupid is only used when
           sysusername is NULL.

           This is the account´s full name. This field is optional, it may be

           The account´s home directory. This field cannot be NULL.

           The pathname to the account´s mailbox. This field is optional, it
           can be NULL in which case the default location is assumed.

           Optional maildir quota on the account´s mailbox (and NULL if no
           quota is set).

           The account´s encrypted password, if available. If the account has
           a cleartext password defined, this field can be set to NULL. The
           encrypted password can take several formats:

           ·   A traditional triple-DES crypted password, or a MD5+salt-hashed
               password, as used in Linux.

           ·    “{MD5}” followed by a base64-encoded MD5 hash of the password.

           ·    “{SHA}” followed by a base64-encoded SHA1 hash of the

           The account´s cleartext password, if available. If the account has
           an encrypted password defined, this field can be set to NULL.

           A comma-separated list of miscellaneous account options. See below
           for more information.

   Account options
       Depending on the configuration of the Courier authentication library,
       accounts may have individual options associated with them. If the
       authentication library configuration does not implement account
       options, the option string will be NULL. Otherwise it will be a
       comma-separated list of “option=value” settings.

       This is the account option implementation that´s used by Courier,
       Courier-IMAP, and SqWebMail packages. Some of the following information
       is obviously not applicable for a particular package. The inapplicable
       bits should be obvious.

       The following options are recognized by the various Courier packages:

       The application is responsible for enforcing all the “disabled” option.
       An authentication request for service “imap”, for example, will succeed
       provided that the userid and the password are valid, even if
       “disableimap=1” is set. The application´s callback_func should check
       for this condition, and return a negative return code.

           If "n" is 1, IMAP access to this account should be disabled.

           If "n" is 1, POP3 access to this account should be disabled.

           If "n" is 1, webmail access to this account should be disabled.

           If "n" is 1, this account should not have access to shared folders
           or be able to share its own folders with other people.

           This account is a member of access group name. Instead of granting
           access rights on individual mail folders to individual accounts,
           the access rights can be granted to an access group “name”, and all
           members of this group get the specified access rights.

           The access group name “administrators” is a reserved group. All
           accounts in the administrators group automatically receive all
           rights to all accessible folders.

           This option may be specified multiple times to specify that the
           account belongs to multiple account groups.

           Append "name" to the name of the top level virtual shared folder
           index file. This setting restricts which virtual shared folders
           this account could possibly access (and that´s on top of whatever
           else the access control lists say). See the virtual shared folder
           documentation for more information.

           For technical reasons, group names may not include comma, tab, "/"
           or "|" characters.


       authlib(3)[2], auth_login(3)[1], auth_getuserinfo(3)[3],
       auth_enumerate(3)[4], auth_passwd(3)[5], auth_getoption(3)[6].


        1. auth_login(3)

        2. authlib(3)

        3. auth_getuserinfo(3)

        4. auth_enumerate(3)

        5. auth_passwd(3)

        6. auth_getoption(3)