NAME
nfssvc —
NFS services
SYNOPSIS
#include
<unistd.h>
#include <nfs/nfs.h>
int
nfssvc(int
flags, void
*argstructp);
DESCRIPTION
The
nfssvc()
function is used by NFS daemons to pass information into 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 two
structures depending on which bits are set in flags.
To enter an
nfsd(8) daemon into the kernel,
nfssvc()
is called with the flag NFSSVC_NFSD and a pointer to
a structure:
struct nfsd_srvargs {
struct nfsd *nsd_nfsd; /* Pointer to in kernel nfsd struct */
uid_t nsd_uid; /* Effective uid mapped to cred */
u_int32_t nsd_haddr; /* IP address of client */
struct xucred 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 */
u_int32_t nsd_ttl; /* credential ttl (sec) */
};
To add further sockets for processing by the
nfsd(8) server daemons the master
nfsd(8) daemon calls
nfssvc()
with the flag NFSSVC_ADDSOCK and a pointer to a
structure:
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
- [
EPERM] - The caller is not the superuser.
- [
EINVAL] - The flag argument consisted of incompatible or otherwise unsupported bits.
SEE ALSO
HISTORY
The nfssvc function 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. 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.