4.4BSD/usr/share/man/cat2/nfssvc.0

NFSSVC(2)                   BSD Programmer's Manual                  NFSSVC(2)

NNAAMMEE
     nnffssssvvcc - NFS services

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<uunniissttdd..hh>>
     ##iinncclluuddee <<nnffss//nnffss..hh>>

     _i_n_t
     nnffssssvvcc(_i_n_t _f_l_a_g_s, _v_o_i_d _*_a_r_g_s_t_r_u_c_t_p);

DDEESSCCRRIIPPTTIIOONN
     The nnffssssvvcc() function is used by the NFS daemons to pass information into
     and out of the kernel and also to enter the kernel as a server daemon.
     The _f_l_a_g_s argument consists of several bits that show what action is to
     be taken once in the kernel and the _a_r_g_s_t_r_u_c_t_p points to one of three
     structures depending on which bits are set in flags.

     On the client side, nfsiod(8) calls nnffssssvvcc() with the _f_l_a_g_s argument set
     to NFSSVC_BIOD and _a_r_g_s_t_r_u_c_t_p set to NULL to enter the kernel as a block
     I/O server daemon.  For NNQQNNFFSS, mount_nfs(8) calls nnffssssvvcc() with the
     NFSSVC_MNTD flag, optionally or'd with the flags NFSSVC_GOTAUTH and
     NFSSVC_AUTHINFAIL along with a pointer to a

     struct nfsd_cargs {
             char            *ncd_dirp;      /* Mount dir path */
             uid_t           ncd_authuid;    /* Effective uid */
             int             ncd_authtype;   /* Type of authenticator */
             int             ncd_authlen;    /* Length of authenticator string */
             char            *ncd_authstr;   /* Authenticator string */
     };

     structure.  The initial call has only the NFSSVC_MNTD flag set to specify
     service for the mount point.  If the mount point is using Kerberos, then
     the mount_nfs(8) daemon will return from nnffssssvvcc() with errno == ENEEDAUTH
     whenever the client side requires an ``rcmd'' authentication ticket for
     the user.  Mount_nfs(8) will attempt to get the Kerberos ticket, and if
     successful will call nnffssssvvcc() with the flags NFSSVC_MNTD and
     NFSSVC_GOTAUTH after filling the ticket into the ncd_authstr field and
     setting the ncd_authlen and ncd_authtype fields of the nfsd_cargs struc-
     ture.  If mount_nfs(8) failed to get the ticket, nnffssssvvcc() will be called
     with the flags NFSSVC_MNTD, NFSSVC_GOTAUTH and NFSSVC_AUTHINFAIL to de-
     note a failed authentication attempt.

     On the server side, nnffssssvvcc() is called with the flag NFSSVC_NFSD and a
     pointer to a

     struct nfsd_srvargs {
             struct nfsd     *nsd_nfsd;      /* Pointer to in kernel nfsd struct */
             uid_t           nsd_uid;        /* Effective uid mapped to cred */
             u_long          nsd_haddr;      /* Ip address of client */
             struct ucred    nsd_cr;         /* Cred. uid maps to */
             int             nsd_authlen;    /* Length of auth string (ret) */
             char            *nsd_authstr;   /* Auth string (ret) */
     };

     to enter the kernel as an nfsd(8) daemon.  Whenever an nfsd(8) daemon re-
     ceives a Kerberos authentication ticket, it will return from nnffssssvvcc()
     with errno == ENEEDAUTH.  The nfsd(8) will attempt to authenticate the
     ticket and generate a set of credentials on the server for the ``user
     id'' specified in the field nsd_uid.  This is done by first authenticat-
     ing the Kerberos ticket and then mapping the Kerberos principal to a lo-
     cal name and getting a set of credentials for that user via.  getpwnam(3)
     and getgrouplist(3).  If successful, the nfsd(8) will call nnffssssvvcc() with
     the NFSSVC_NFSD and NFSSVC_AUTHIN flags set to pass the credential map-
     ping in nsd_cr into the kernel to be cached on the server socket for that
     client.  If the authentication failed, nfsd(8) calls nnffssssvvcc() with the
     flags NFSSVC_NFSD and NFSSVC_AUTHINFAIL to denote an authentication fail-
     ure.

     The master nfsd(8) server daemon calls nnffssssvvcc() with the flag
     NFSSVC_ADDSOCK and a pointer to a

     struct nfsd_args {
             int     sock;           /* Socket to serve */
             caddr_t name;           /* Client address for connection based sockets */
             int     namelen;        /* Length of name */
     };

     to pass a server side NFS socket into the kernel for servicing by the
     nfsd(8) daemons.

RREETTUURRNN VVAALLUUEESS
     Normally nnffssssvvcc does not return unless the server is terminated by a sig-
     nal when a value of 0 is returned.  Otherwise, -1 is returned and the
     global variable _e_r_r_n_o is set to specify the error.

EERRRROORRSS
     [ENEEDAUTH]  This special error value is really used for authentication
                  support, particularly Kerberos, as explained above.

     [EPERM]      The caller is not the super-user.

SSEEEE AALLSSOO
     nfsd(8),  mount_nfs(8),  nfsiod(8)

HHIISSTTOORRYY
     The nnffssssvvcc function first appeared in 4.4BSD.

BBUUGGSS
     The nnffssssvvcc system call is designed specifically for the NFS support dae-
     mons and as such is specific to their requirements.  It should really re-
     turn values to indicate the need for authentication support, since
     ENEEDAUTH is not really an error.  Several fields of the argument struc-
     tures are assumed to be valid and sometimes to be unchanged from a previ-
     ous call, such that nnffssssvvcc must be used with extreme care.

4.4BSD                           June 9, 1993                                2