NAME
nfssvc — NFS servicesLIBRARY
Standard C Library (libc, -lc)SYNOPSIS
#include <sys/param.h>#include <sys/mount.h>
#include <sys/time.h>
#include <nfs/rpcv2.h>
#include <nfsserver/nfs.h>
#include <unistd.h> int
nfssvc(int flags, void *argstructp);
DESCRIPTION
The nfssvc() system call 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 flags argument consists of several bits that show what action is to be taken once in the kernel and the argstructp points to one of three structures depending on which bits are set in flags. On the client side, nfsiod(8) calls nfssvc() with the flags argument set toNFSSVC_BIOD and
argstructp set to
NULL to enter the kernel as a block I/O
server daemon. For NQNFS, mount_nfs(8) calls
nfssvc() 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 */
u_char *ncd_authstr; /* Authenticator string */
int ncd_verflen; /* and the verifier */
u_char *ncd_verfstr;
NFSKERBKEY_T ncd_key; /* Session key */
};
NFSSVC_MNTD flag set to specify service for
the mount point. If the mount point is using Kerberos, then the
mount_nfs(8) utility will return from
nfssvc() with
errno ==
ENEEDAUTH whenever the client side requires
an ``rcmd'' authentication ticket for the user. The
mount_nfs(8) utility will attempt to get the
Kerberos ticket, and if successful will call
nfssvc() 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 structure. If mount_nfs(8)
failed to get the ticket, nfssvc() will be called
with the flags NFSSVC_MNTD,
NFSSVC_GOTAUTH and
NFSSVC_AUTHINFAIL to denote a failed
authentication attempt.
On the server side, nfssvc() 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 */
uint32_t nsd_haddr; /* Ip address of client */
struct ucred nsd_cr; /* Cred. uid maps to */
int nsd_authlen; /* Length of auth string (ret) */
u_char *nsd_authstr; /* Auth string (ret) */
int nsd_verflen; /* and the verifier */
u_char *nsd_verfstr;
struct timeval nsd_timestamp; /* timestamp from verifier */
uint32_t nsd_ttl; /* credential ttl (sec) */
NFSKERBKEY_T nsd_key; /* Session key */
};
ENEEDAUTH. The
nfsd(8) utility 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 authenticating the
Kerberos ticket and then mapping the Kerberos principal to a local name and
getting a set of credentials for that user via
getpwnam(3) and
getgrouplist(3). If successful, the
nfsd(8) utility will call
nfssvc() with the
NFSSVC_NFSD and
NFSSVC_AUTHIN flags set to pass the
credential mapping in nsd_cr into the kernel to be cached on the server socket
for that client. If the authentication failed,
nfsd(8) calls
nfssvc() with the flags
NFSSVC_NFSD and
NFSSVC_AUTHINFAIL to denote an
authentication failure.
The master nfsd(8) server daemon calls
nfssvc() 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 */
};
RETURN VALUES
Normally nfssvc() does not return unless the server is terminated by a signal when a value of 0 is returned. Otherwise, -1 is returned and the global variable errno is set to specify the error.ERRORS
- [
ENEEDAUTH] - This special error value is really used for authentication support, particularly Kerberos, as explained above.
- [
EPERM] - The caller is not the super-user.
SEE ALSO
mount_nfs(8), nfsd(8), nfsiod(8)HISTORY
The nfssvc() system call first appeared in 4.4BSD.BUGS
The nfssvc() system call is designed specifically for the NFS support daemons and as such is specific to their requirements. It should really return values to indicate the need for authentication support, sinceENEEDAUTH is not really an error.
Several fields of the argument structures are assumed to be valid and
sometimes to be unchanged from a previous call, such that
nfssvc() must be used with extreme care.| June 9, 1993 | Debian |