Modify nfsd.c to add support for the experimental nfs server.

This includes the addition of a new flag "-4" that will force
use of the experimental server with nfsv4 support in it. This
commit also adds two new man pages to the repository that are
NFSv4 specific. One describes the file used by the server to
restart nfsv4 services safely. The other is a brief overview
of nfsv4 and its setup.

Reviewed by:	dfr
Approved by:	kib (mentor)

1 files changed, 108 insertions, 25 deletions

diff --git a/usr.sbin/nfsd/nfsd.c b/usr.sbin/nfsd/nfsd.c
index 788d1c2..9afe62c 100644
--- a/usr.sbin/nfsd/nfsd.c
+++ b/usr.sbin/nfsd/nfsd.c
@@ -48,6 +48,7 @@ static const char rcsid[] =
 #include <sys/syslog.h>
 #include <sys/wait.h>
 #include <sys/mount.h>
+#include <sys/fcntl.h>
 #include <sys/linker.h>
 #include <sys/module.h>
 
@@ -59,6 +60,7 @@ static const char rcsid[] =
 #include <nfs/rpcv2.h>
 #include <nfs/nfsproto.h>
 #include <nfsserver/nfs.h>
+#include <nfs/nfssvc.h>
 
 #include <err.h>
 #include <errno.h>
@@ -77,11 +79,14 @@ int	debug = 1;
 int	debug = 0;
 #endif
 
+#define	NFSD_STABLERESTART	"/var/db/nfs-stablerestart"
 #define	MAXNFSDCNT	256
 #define	DEFNFSDCNT	 4
 pid_t	children[MAXNFSDCNT];	/* PIDs of children */
 int	nfsdcnt;		/* number of children */
 int	new_syscall;
+int	run_v4server = 0;	/* Force running of nfsv4 server */
+int	nfssvc_nfsd;		/* Set to correct NFSSVC_xxx flag */
 
 void	cleanup(int);
 void	child_cleanup(int);
@@ -112,6 +117,7 @@ void	usage(void);
  *	-d - unregister with rpcbind
  *	-t - support tcp nfs clients
  *	-u - support udp nfs clients
+ *	-4 - forces it to run a server that supports nfsv4
  * followed by "n" which is the number of nfsds' to fork off
  */
 int
@@ -131,20 +137,15 @@ main(int argc, char **argv)
 	int tcp6sock, ip6flag, tcpflag, tcpsock;
 	int udpflag, ecode, s, srvcnt;
 	int bindhostc, bindanyflag, rpcbreg, rpcbregcnt;
+	int stablefd, nfssvc_addsock;
 	char **bindhost = NULL;
 	pid_t pid;
 
-	if (modfind("nfsserver") < 0) {
-		/* Not present in kernel, try loading it */
-		if (kldload("nfsserver") < 0 || modfind("nfsserver") < 0)
-			errx(1, "NFS server is not available");
-	}
-
 	nfsdcnt = DEFNFSDCNT;
 	unregister = reregister = tcpflag = maxsock = 0;
 	bindanyflag = udpflag = connect_type_cnt = bindhostc = 0;
-#define	GETOPT	"ah:n:rdtu"
-#define	USAGE	"[-ardtu] [-n num_servers] [-h bindip]"
+#define	GETOPT	"ah:n:rdtu4"
+#define	USAGE	"[-ardtu4] [-n num_servers] [-h bindip]"
 	while ((ch = getopt(argc, argv, GETOPT)) != -1)
 		switch (ch) {
 		case 'a':
@@ -179,6 +180,9 @@ main(int argc, char **argv)
 		case 'u':
 			udpflag = 1;
 			break;
+		case '4':
+			run_v4server = 1;
+			break;
 		default:
 		case '?':
 			usage();
@@ -203,6 +207,25 @@ main(int argc, char **argv)
 		}
 	}
 
+	/*
+	 * If the "-4" option was specified OR only the nfsd module is
+	 * found in the server, run "nfsd".
+	 * Otherwise, try and run "nfsserver".
+	 */
+	if (run_v4server > 0) {
+		if (modfind("nfsd") < 0) {
+			/* Not present in kernel, try loading it */
+			if (kldload("nfsd") < 0 || modfind("nfsd") < 0)
+				errx(1, "NFS server is not available");
+		}
+	} else if (modfind("nfsserver") < 0 && modfind("nfsd") >= 0) {
+		run_v4server = 1;
+	} else if (modfind("nfsserver") < 0) {
+		/* Not present in kernel, try loading it */
+		if (kldload("nfsserver") < 0 || modfind("nfsserver") < 0)
+			errx(1, "NFS server is not available");
+	}
+
 	ip6flag = 1;
 	s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 	if (s == -1) {
@@ -328,15 +351,47 @@ main(int argc, char **argv)
 	openlog("nfsd", LOG_PID, LOG_DAEMON);
 
 	/*
-	 * Figure out if the kernel supports the new-style
-	 * NFSSVC_NFSD. Old kernels will return ENXIO because they
-	 * don't recognise the flag value, new ones will return EINVAL
-	 * because argp is NULL.
+	 * For V4, we open the stablerestart file and call nfssvc()
+	 * to get it loaded. This is done before the daemons do the
+	 * regular nfssvc() call to service NFS requests.
+	 * (This way the file remains open until the last nfsd is killed
+	 *  off.)
+	 * Note that this file is not created by this daemon and can
+	 * only be relocated by recompiling the daemon, in order to
+	 * minimize accidentally starting up with the wrong file.
+	 * If should be created as an empty file Read and Write for
+	 * root before the first time you run NFS v4 and should never
+	 * be re-initialized if at all possible. It should live on a
+	 * local, non-volatile storage device that does not do hardware
+	 * level write-back caching. (See SCSI doc for more information
+	 * on how to prevent write-back caching on SCSI disks.)
 	 */
-	new_syscall = FALSE;
-	if (nfssvc(NFSSVC_NFSD, NULL) < 0 && errno == EINVAL)
+	if (run_v4server > 0) {
+		stablefd = open(NFSD_STABLERESTART, O_RDWR, 0);
+		if (stablefd < 0) {
+			syslog(LOG_ERR, "Can't open %s\n", NFSD_STABLERESTART);
+			exit(1);
+		}
+		if (nfssvc(NFSSVC_STABLERESTART, (caddr_t)&stablefd) < 0) {
+			syslog(LOG_ERR, "Can't read stable storage file\n");
+			exit(1);
+		}
+		nfssvc_addsock = NFSSVC_NFSDADDSOCK;
+		nfssvc_nfsd = NFSSVC_NFSDNFSD;
 		new_syscall = TRUE;
-	new_syscall = FALSE;
+	} else {
+		nfssvc_addsock = NFSSVC_ADDSOCK;
+		nfssvc_nfsd = NFSSVC_NFSD;
+		/*
+		 * Figure out if the kernel supports the new-style
+		 * NFSSVC_NFSD. Old kernels will return ENXIO because they
+		 * don't recognise the flag value, new ones will return EINVAL
+		 * because argp is NULL.
+		 */
+		new_syscall = FALSE;
+		if (nfssvc(NFSSVC_NFSD, NULL) < 0 && errno == EINVAL)
+			new_syscall = TRUE;
+	}
 
 	if (!new_syscall) {
 		/* If we use UDP only, we start the last server below. */
@@ -413,7 +468,7 @@ main(int argc, char **argv)
 				addsockargs.sock = sock;
 				addsockargs.name = NULL;
 				addsockargs.namelen = 0;
-				if (nfssvc(NFSSVC_ADDSOCK, &addsockargs) < 0) {
+				if (nfssvc(nfssvc_addsock, &addsockargs) < 0) {
 					syslog(LOG_ERR, "can't Add UDP socket");
 					nfsd_exit(1);
 				}
@@ -481,7 +536,7 @@ main(int argc, char **argv)
 				addsockargs.sock = sock;
 				addsockargs.name = NULL;
 				addsockargs.namelen = 0;
-				if (nfssvc(NFSSVC_ADDSOCK, &addsockargs) < 0) {
+				if (nfssvc(nfssvc_addsock, &addsockargs) < 0) {
 					syslog(LOG_ERR,
 					    "can't add UDP6 socket");
 					nfsd_exit(1);
@@ -711,7 +766,7 @@ main(int argc, char **argv)
 					addsockargs.sock = msgsock;
 					addsockargs.name = (caddr_t)&inetpeer;
 					addsockargs.namelen = len;
-					nfssvc(NFSSVC_ADDSOCK, &addsockargs);
+					nfssvc(nfssvc_addsock, &addsockargs);
 					(void)close(msgsock);
 				} else if (FD_ISSET(tcpsock, &v6bits)) {
 					len = sizeof(inet6peer);
@@ -733,7 +788,7 @@ main(int argc, char **argv)
 					addsockargs.sock = msgsock;
 					addsockargs.name = (caddr_t)&inet6peer;
 					addsockargs.namelen = len;
-					nfssvc(NFSSVC_ADDSOCK, &addsockargs);
+					nfssvc(nfssvc_addsock, &addsockargs);
 					(void)close(msgsock);
 				}
 			}
@@ -861,19 +916,47 @@ nfsd_exit(int status)
 void
 start_server(int master)
 {
-	char principal[128];
-	char hostname[128];
+	char principal[MAXHOSTNAMELEN + 5];
 	struct nfsd_nfsd_args nfsdargs;
-	int status;
+	int status, error;
+	char hostname[MAXHOSTNAMELEN + 1], *cp;
+	struct addrinfo *aip, hints;
 
 	status = 0;
 	if (new_syscall) {
-		gethostname(hostname, sizeof(hostname));
-		snprintf(principal, sizeof(principal), "nfs@%s", hostname);
+		gethostname(hostname, sizeof (hostname));
+		snprintf(principal, sizeof (principal), "nfs@%s", hostname);
+		if ((cp = strchr(hostname, '.')) == NULL ||
+		    *(cp + 1) == '\0') {
+			/* If not fully qualified, try getaddrinfo() */
+			memset((void *)&hints, 0, sizeof (hints));
+			hints.ai_flags = AI_CANONNAME;
+			error = getaddrinfo(hostname, NULL, &hints, &aip);
+			if (error == 0) {
+				if (aip->ai_canonname != NULL &&
+				    (cp = strchr(aip->ai_canonname, '.')) !=
+				    NULL && *(cp + 1) != '\0')
+					snprintf(principal, sizeof (principal),
+					    "nfs@%s", aip->ai_canonname);
+				freeaddrinfo(aip);
+			}
+		}
 		nfsdargs.principal = principal;
 		nfsdargs.minthreads = nfsdcnt;
 		nfsdargs.maxthreads = nfsdcnt;
-		if (nfssvc(NFSSVC_NFSD, &nfsdargs) < 0) {
+		error = nfssvc(nfssvc_nfsd, &nfsdargs);
+		if (error < 0 && errno == EAUTH) {
+			/*
+			 * This indicates that it could not register the
+			 * rpcsec_gss credentials, usually because the
+			 * gssd daemon isn't running.
+			 * (only the experimental server with nfsv4)
+			 */
+			syslog(LOG_ERR, "No gssd, using AUTH_SYS only");
+			principal[0] = '\0';
+			error = nfssvc(nfssvc_nfsd, &nfsdargs);
+		}
+		if (error < 0) {
 			syslog(LOG_ERR, "nfssvc: %m");
 			status = 1;
 		}