Change the following kernel options to environment variables:

    BOOTP -> bootp
    BOOTP_NFSROOT -> bootp.nfsroot
    BOOTP_NFSV3 -> bootp.nfsv3
    BOOTP_COMPAT -> bootp.compat
    BOOTP_WIRED_TO -> bootp.wired_to

This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:

    bootp="YES"
    bootp.nfsroot="YES"
    bootp.nfsv3="YES"
    bootp.wired_to="bge1"

or even setting the variables manually from the OK prompt.

17 files changed, 169 insertions, 143 deletions

diff --git a/sys/alpha/alpha/autoconf.c b/sys/alpha/alpha/autoconf.c
index d3ffb23..0cf7e65 100644
--- a/sys/alpha/alpha/autoconf.c
+++ b/sys/alpha/alpha/autoconf.c
@@ -27,7 +27,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_bootp.h"
 #include "opt_isa.h"
 #include "opt_nfs.h"
 #include "opt_nfsroot.h"
@@ -203,11 +202,12 @@ void
 cpu_rootconf()
 {
 #if defined(NFSCLIENT) && defined(NFS_ROOT)
-	int	order = 0;
-#if !defined(BOOTP_NFSROOT)
-	if (nfs_diskless_valid)
-#endif
-		rootdevnames[order++] = "nfs:";
+	char	*cp = NULL;
+
+	if (nfs_diskless_valid || (cp = getenv("bootp.nfsroot")) != NULL)
+		rootdevnames[0] = "nfs:";
+	if (cp != NULL)
+		freeenv(cp);
 #endif
 }
 SYSINIT(cpu_rootconf, SI_SUB_ROOT_CONF, SI_ORDER_FIRST, cpu_rootconf, NULL)
diff --git a/sys/amd64/amd64/autoconf.c b/sys/amd64/amd64/autoconf.c
index c646741..f5a4164 100644
--- a/sys/amd64/amd64/autoconf.c
+++ b/sys/amd64/amd64/autoconf.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
  * devices are determined (from possibilities mentioned in ioconf.c),
  * and the drivers are initialized.
  */
-#include "opt_bootp.h"
 #include "opt_isa.h"
 #include "opt_nfs.h"
 #include "opt_nfsroot.h"
@@ -143,15 +142,19 @@ configure_final(dummy)
 void
 cpu_rootconf()
 {
-#ifdef BOOTP
-        bootpc_init();
-#endif
+	char	*cp;
+
+	if ((cp = getenv("bootp")) != NULL) {
+        	bootpc_init();
+		freeenv(cp);
+	}
 #if defined(NFSCLIENT) && defined(NFS_ROOT)
-#if !defined(BOOTP_NFSROOT)
-	nfs_setup_diskless();
-	if (nfs_diskless_valid)
-#endif
+	if ((cp = getenv("bootp.nfsroot")) == NULL)
+		nfs_setup_diskless();
+	if (cp != NULL || nfs_diskless_valid)
 		rootdevnames[0] = "nfs:";
+	if (cp != NULL)
+		freeenv(cp);
 #endif
 }
 SYSINIT(cpu_rootconf, SI_SUB_ROOT_CONF, SI_ORDER_FIRST, cpu_rootconf, NULL)
diff --git a/sys/boot/common/dev_net.c b/sys/boot/common/dev_net.c
index b7ccbca..2e136c4 100644
--- a/sys/boot/common/dev_net.c
+++ b/sys/boot/common/dev_net.c
@@ -273,7 +273,7 @@ net_getparams(sock)
     /*  
      * If present, strip the server's address off of the rootpath
      * before passing it along.  This allows us to be compatible with
-     * the kernel's diskless (BOOTP_NFSROOT) booting conventions
+     * the kernel's diskless (kenv bootp.nfsroot=1) booting conventions
      */
     for (i = 0; rootpath[i] != '\0' && i < FNAME_SIZE; i++)
 	    if (rootpath[i] == ':')
diff --git a/sys/boot/common/loader.8 b/sys/boot/common/loader.8
index a77a828..958b33b 100644
--- a/sys/boot/common/loader.8
+++ b/sys/boot/common/loader.8
@@ -352,6 +352,29 @@ by the kernel during the boot phase.
 List of semicolon-separated search path for bootable kernels.
 The default is
 .Dq Li kernel;kernel.old .
+.It Va bootp
+Setting this variable tells the kernel to use BOOTP to obtain an IP address
+and hostname at boot time.
+The kernel must be built with
+.Dv NFSCLIENT
+and
+.Dv NFS_ROOT
+defined.
+.It Va bootp.compat
+Setting this variable enables a workaround for broken BOOTP daemons.
+.It Va bootp.nfsroot
+Setting this variable tells the kernel to NFS mount the root filesystem using
+BOOTP information.
+.It Va bootp.nfsv3
+Setting this variable tells the kernel to use NFS version 3 to mount the root
+filesystem.
+.It Va bootp.wired_to
+This variable may be set to the name of the interface that is to be used to
+boot from when
+.Va bootp
+is set.
+If it is not set, the system will attempt to boot from all available
+interfaces, using the first one found.
 .It Va console
 Defines the current console.
 .It Va currdev
diff --git a/sys/boot/forth/loader.conf b/sys/boot/forth/loader.conf
index 992ab06..db43699 100644
--- a/sys/boot/forth/loader.conf
+++ b/sys/boot/forth/loader.conf
@@ -67,6 +67,11 @@ module_path="/boot/kernel;/boot/modules"	# Set the module search path
 #boot_single=""		# Start system in single-user mode
 #boot_userconfig=""	# Run kernel's interactive device configuration program
 #boot_verbose=""	# Causes extra debugging information to be printed
+#bootp=""		# Use BOOTP to obtain an IP address at boot time
+#bootp.compat=""	# Enable a workaround for broken bootp daemons
+#bootp.nfsroot=""	# NFS mount the root filesystem using BOOTP info
+#bootp.nfsv3=""		# Use NFS v3 to mount the root filesystem
+#bootp.wired_to="fxp0"	# Use this interface only when bootp is enabled
 #init_path="/sbin/init:/sbin/oinit:/sbin/init.bak:/stand/sysinstall"
 			# Sets the list of init candidates
 #dumpdev="ad0s1b"	# Set device for crash dumps
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index fd1b42a..e1cbcad 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -2124,14 +2124,7 @@ device		pps
 device		lpbb
 device		pcfclock
 
-# Kernel BOOTP support
-
-options 	BOOTP		# Use BOOTP to obtain IP address/hostname
-				# Requires NFSCLIENT and NFS_ROOT
-options 	BOOTP_NFSROOT	# NFS mount root filesystem using BOOTP info
-options 	BOOTP_NFSV3	# Use NFS v3 to NFS mount root
-options 	BOOTP_COMPAT	# Workaround for broken bootp daemons.
-options 	BOOTP_WIRED_TO=fxp0 # Use interface fxp0 for BOOTP
+# Kernel BOOTP support - see loader(8)
 
 #
 # Add tie-ins for a hardware watchdog.  This only enables the hooks;
diff --git a/sys/conf/files b/sys/conf/files
index 7237d64..1638778 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1573,8 +1573,8 @@ netsmb/smb_trantcp.c		optional netsmb
 netsmb/smb_usr.c		optional netsmb
 nfs/nfs_common.c		optional nfsclient
 nfs/nfs_common.c		optional nfsserver
-nfsclient/bootp_subr.c		optional bootp nfsclient
-nfsclient/krpc_subr.c		optional bootp nfsclient
+nfsclient/bootp_subr.c		standard
+nfsclient/krpc_subr.c		optional nfsclient
 nfsclient/nfs_bio.c		optional nfsclient
 nfsclient/nfs_diskless.c	optional nfsclient nfs_root
 nfsclient/nfs_node.c		optional nfsclient
diff --git a/sys/conf/options b/sys/conf/options
index b593318..71cf0fe 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -310,11 +310,6 @@ ALTQ_CDNR		opt_altq.h
 ALTQ_PRIQ		opt_altq.h
 ALTQ_NOPCC		opt_altq.h
 ALTQ_DEBUG		opt_altq.h
-BOOTP			opt_bootp.h
-BOOTP_COMPAT		opt_bootp.h
-BOOTP_NFSROOT		opt_bootp.h
-BOOTP_NFSV3		opt_bootp.h
-BOOTP_WIRED_TO		opt_bootp.h
 BRIDGE			opt_bdg.h
 DEV_PF			opt_pf.h
 DEV_PFLOG		opt_pf.h
diff --git a/sys/i386/i386/autoconf.c b/sys/i386/i386/autoconf.c
index c213a68..3239c1d 100644
--- a/sys/i386/i386/autoconf.c
+++ b/sys/i386/i386/autoconf.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
  * devices are determined (from possibilities mentioned in ioconf.c),
  * and the drivers are initialized.
  */
-#include "opt_bootp.h"
 #include "opt_isa.h"
 #include "opt_nfs.h"
 #include "opt_nfsroot.h"
@@ -181,15 +180,19 @@ configure_final(dummy)
 void
 cpu_rootconf()
 {
-#ifdef BOOTP
-        bootpc_init();
-#endif
+	char	*cp;
+
+	if ((cp = getenv("bootp")) != NULL) {
+        	bootpc_init();
+		freeenv(cp);
+	}
 #if defined(NFSCLIENT) && defined(NFS_ROOT)
-#if !defined(BOOTP_NFSROOT)
-	nfs_setup_diskless();
-	if (nfs_diskless_valid)
-#endif
+	if ((cp = getenv("bootp.nfsroot")) == NULL)
+		nfs_setup_diskless();
+	if (cp != NULL || nfs_diskless_valid)
 		rootdevnames[0] = "nfs:";
+	if (cp != NULL)
+		freeenv(cp);
 #endif
 }
 SYSINIT(cpu_rootconf, SI_SUB_ROOT_CONF, SI_ORDER_FIRST, cpu_rootconf, NULL)
diff --git a/sys/i386/i386/locore.s b/sys/i386/i386/locore.s
index 72ef2bf..50f32d4 100644
--- a/sys/i386/i386/locore.s
+++ b/sys/i386/i386/locore.s
@@ -39,7 +39,6 @@
  *			and many others.
  */
 
-#include "opt_bootp.h"
 #include "opt_compat.h"
 #include "opt_nfsroot.h"
 #include "opt_pmap.h"
@@ -542,7 +541,6 @@ got_common_bi_size:
 	movsb
 
 #ifdef NFS_ROOT
-#ifndef BOOTP_NFSV3
 	/*
 	 * If we have a nfs_diskless structure copy it in
 	 */
@@ -557,7 +555,6 @@ got_common_bi_size:
 	movl	$R(nfs_diskless_valid),%edi
 	movl	$1,(%edi)
 #endif
-#endif
 
 	/*
 	 * The old style disk boot.
diff --git a/sys/ia64/ia64/autoconf.c b/sys/ia64/ia64/autoconf.c
index dcfd1b0..df2e03b 100644
--- a/sys/ia64/ia64/autoconf.c
+++ b/sys/ia64/ia64/autoconf.c
@@ -26,7 +26,6 @@
  * $FreeBSD$
  */
 
-#include "opt_bootp.h"
 #include "opt_isa.h"
 #include "opt_nfs.h"
 #include "opt_nfsroot.h"
@@ -54,9 +53,7 @@
 static void	configure(void *);
 SYSINIT(configure, SI_SUB_CONFIGURE, SI_ORDER_THIRD, configure, NULL)
 
-#ifdef BOOTP
 void bootpc_init(void);
-#endif
 
 #ifdef DEV_ISA
 #include <isa/isavar.h>
@@ -99,18 +96,18 @@ configure(void *dummy)
 void
 cpu_rootconf()
 {
-#if defined(NFSCLIENT) && defined(NFS_ROOT)
-	int	order = 0;
-#endif
+	char	*cp;
 
-#ifdef BOOTP
-	bootpc_init();
-#endif
+	if ((cp = getenv("bootp")) != NULL) {
+        	bootpc_init();
+		freeenv(cp);
+		cp = NULL;
+	}
 #if defined(NFSCLIENT) && defined(NFS_ROOT)
-#if !defined(BOOTP_NFSROOT)
-	if (nfs_diskless_valid)
-#endif
-		rootdevnames[order++] = "nfs:";
+	if (nfs_diskless_valid || (cp = getenv("bootp.nfsroot")) != NULL)
+		rootdevnames[0] = "nfs:";
+	if (cp != NULL)
+		freeenv(cp);
 #endif
 }
 SYSINIT(cpu_rootconf, SI_SUB_ROOT_CONF, SI_ORDER_FIRST, cpu_rootconf, NULL)
diff --git a/sys/modules/nfs4client/Makefile b/sys/modules/nfs4client/Makefile
index 723f571..0259817 100644
--- a/sys/modules/nfs4client/Makefile
+++ b/sys/modules/nfs4client/Makefile
@@ -6,7 +6,7 @@ KMOD=	nfs4client
 SRCS=	vnode_if.h \
 	nfs_bio.c nfs_lock.c nfs_node.c nfs_nfsiod.c \
 	nfs_common.c \
-	opt_inet.h opt_nfs.h opt_bootp.h opt_nfsroot.h \
+	opt_inet.h opt_nfs.h opt_nfsroot.h \
 	nfs4_dev.c nfs4_idmap.c nfs4_socket.c nfs4_subs.c \
 	nfs4_vfs_subs.c  nfs4_vfsops.c nfs4_vn_subs.c nfs4_vnops.c
 SRCS+=	opt_inet6.h
diff --git a/sys/modules/nfsclient/Makefile b/sys/modules/nfsclient/Makefile
index 11b83eb..688bd37 100644
--- a/sys/modules/nfsclient/Makefile
+++ b/sys/modules/nfsclient/Makefile
@@ -7,7 +7,7 @@ KMOD=	nfsclient
 SRCS=	vnode_if.h \
 	nfs_bio.c nfs_lock.c nfs_node.c nfs_socket.c nfs_subs.c nfs_nfsiod.c \
 	nfs_vfsops.c nfs_vnops.c nfs_common.c \
-	opt_inet.h opt_nfs.h opt_bootp.h opt_nfsroot.h
+	opt_inet.h opt_nfs.h opt_nfsroot.h
 SRCS+=	nfs4_dev.c nfs4_idmap.c nfs4_socket.c nfs4_subs.c \
 	nfs4_vfs_subs.c  nfs4_vfsops.c nfs4_vn_subs.c nfs4_vnops.c
 SRCS+=	opt_inet6.h
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 048f613..77c8c79 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -30,7 +30,6 @@
  * $FreeBSD$
  */
 
-#include "opt_bootp.h"
 #include "opt_ipfw.h"
 #include "opt_ipdn.h"
 #include "opt_ipdivert.h"
@@ -299,6 +298,7 @@ ip_input(struct mbuf *m)
 	struct ipq *fp;
 	struct in_ifaddr *ia = NULL;
 	struct ifaddr *ifa;
+	char   *cp;
 	int    i, checkif, hlen = 0;
 	u_short sum;
 	struct in_addr pkt_dst;
@@ -598,10 +598,11 @@ pass:
 				goto ours;
 			if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
 				goto ours;
-#ifdef BOOTP_COMPAT
-			if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
-				goto ours;
-#endif
+			if ((cp = getenv("bootp.compat")) != NULL) {
+				freeenv(cp);
+				if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
+					goto ours;
+			}
 		}
 	}
 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
diff --git a/sys/nfs4client/nfs4_vfsops.c b/sys/nfs4client/nfs4_vfsops.c
index e20d176..c9b3e3c 100644
--- a/sys/nfs4client/nfs4_vfsops.c
+++ b/sys/nfs4client/nfs4_vfsops.c
@@ -62,7 +62,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_bootp.h"
 #include "opt_nfsroot.h"
 
 #include <sys/param.h>
diff --git a/sys/nfsclient/bootp_subr.c b/sys/nfsclient/bootp_subr.c
index 2132ef5..d68a94f 100644
--- a/sys/nfsclient/bootp_subr.c
+++ b/sys/nfsclient/bootp_subr.c
@@ -43,8 +43,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_bootp.h"
-
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
@@ -590,6 +588,7 @@ bootpc_call(struct bootpc_globalcontext *gctx, struct thread *td)
 	int gotrootpath;
 	int retry;
 	const char *s;
+	char *cp;
 
 	NET_ASSERT_GIANT();
 
@@ -954,14 +953,19 @@ bootpc_call(struct bootpc_globalcontext *gctx, struct thread *td)
 		error = 0;
 		goto out;
 	}
-#ifndef BOOTP_NFSROOT
-	for (ifctx = gctx->interfaces; ifctx != NULL; ifctx = ifctx->next) {
-		if (bootpc_ifctx_isresolved(ifctx) != 0) {
-			error = 0;
-			goto out;
+
+	if ((cp = getenv("bootp.nfsroot")) != NULL)
+		freeenv(cp);
+	else {
+		for (ifctx = gctx->interfaces; ifctx != NULL;
+		    ifctx = ifctx->next) {
+			if (bootpc_ifctx_isresolved(ifctx) != 0) {
+				error = 0;
+				goto out;
+			}
 		}
 	}
-#endif
+
 	error = ETIMEDOUT;
 	goto out;
 
@@ -1641,10 +1645,9 @@ bootpc_init(void)
 	struct bootpc_ifcontext *ifctx, *nctx;	/* Interface BOOTP contexts */
 	struct bootpc_globalcontext *gctx; 	/* Global BOOTP context */
 	struct ifnet *ifp;
-	int error;
-#ifndef BOOTP_WIRED_TO
+	char *cp, *bootp_wired_to;
+	int bootp_nfsroot, error;
 	int ifcnt;
-#endif
 	struct nfsv3_diskless *nd;
 	struct thread *td;
 
@@ -1667,31 +1670,31 @@ bootpc_init(void)
 	/*
 	 * Find a network interface.
 	 */
-#ifdef BOOTP_WIRED_TO
-	printf("bootpc_init: wired to interface '%s'\n",
-	       __XSTRING(BOOTP_WIRED_TO));
-	allocifctx(gctx);
-#else
-	/*
-	 * Preallocate interface context storage, if another interface
-	 * attaches and wins the race, it won't be eligible for bootp.
-	 */
-	IFNET_RLOCK();
-	for (ifp = TAILQ_FIRST(&ifnet), ifcnt = 0;
-	     ifp != NULL;
-	     ifp = TAILQ_NEXT(ifp, if_link)) {
-		if ((ifp->if_flags &
-		     (IFF_LOOPBACK | IFF_POINTOPOINT | IFF_BROADCAST)) !=
-		    IFF_BROADCAST)
-			continue;
-		ifcnt++;
-	}
-	IFNET_RUNLOCK();
-	if (ifcnt == 0)
-		panic("bootpc_init: no eligible interfaces");
-	for (; ifcnt > 0; ifcnt--)
+	if ((bootp_wired_to = getenv("bootp.wired_to")) != NULL) {
+		printf("bootpc_init: wired to interface '%s'\n",
+		    bootp_wired_to);
 		allocifctx(gctx);
-#endif
+	} else {
+		/*
+		 * Preallocate interface context storage, if another interface
+		 * attaches and wins the race, it won't be eligible for bootp.
+		 */
+		IFNET_RLOCK();
+		for (ifp = TAILQ_FIRST(&ifnet), ifcnt = 0;
+		     ifp != NULL;
+		     ifp = TAILQ_NEXT(ifp, if_link)) {
+			if ((ifp->if_flags &
+			    (IFF_LOOPBACK | IFF_POINTOPOINT | IFF_BROADCAST)) !=
+			    IFF_BROADCAST)
+				continue;
+			ifcnt++;
+		}
+		IFNET_RUNLOCK();
+		if (ifcnt == 0)
+			panic("bootpc_init: no eligible interfaces");
+		for (; ifcnt > 0; ifcnt--)
+			allocifctx(gctx);
+	}
 
 	IFNET_RLOCK();
 	for (ifp = TAILQ_FIRST(&ifnet), ifctx = gctx->interfaces;
@@ -1699,29 +1702,24 @@ bootpc_init(void)
 	     ifp = TAILQ_NEXT(ifp, if_link)) {
 		strlcpy(ifctx->ireq.ifr_name, ifp->if_xname,
 		    sizeof(ifctx->ireq.ifr_name));
-#ifdef BOOTP_WIRED_TO
-		if (strcmp(ifctx->ireq.ifr_name,
-			   __XSTRING(BOOTP_WIRED_TO)) != 0)
-			continue;
-#else
-		if ((ifp->if_flags &
-		     (IFF_LOOPBACK | IFF_POINTOPOINT | IFF_BROADCAST)) !=
+		if (bootp_wired_to) {
+			if (strcmp(ifctx->ireq.ifr_name, bootp_wired_to) != 0)
+				continue;
+		} else if ((ifp->if_flags &
+		    (IFF_LOOPBACK | IFF_POINTOPOINT | IFF_BROADCAST)) !=
 		    IFF_BROADCAST)
 			continue;
-#endif
 		ifctx->ifp = ifp;
 		ifctx = ifctx->next;
 	}
 	IFNET_RUNLOCK();
 
 	if (gctx->interfaces == NULL || gctx->interfaces->ifp == NULL) {
-#ifdef BOOTP_WIRED_TO
-		panic("bootpc_init: Could not find interface specified "
-		      "by BOOTP_WIRED_TO: "
-		      __XSTRING(BOOTP_WIRED_TO));
-#else
-		panic("bootpc_init: no suitable interface");
-#endif
+		if (bootp_wired_to)
+			panic("bootpc_init: Could not find interface specified "
+			    "by bootp.wired_to: %s", bootp_wired_to);
+		else
+			panic("bootpc_init: no suitable interface");
 	}
 
 	for (ifctx = gctx->interfaces; ifctx != NULL; ifctx = ifctx->next)
@@ -1732,12 +1730,17 @@ bootpc_init(void)
 
 	error = bootpc_call(gctx, td);
 
+	if ((cp = getenv("bootp.nfsroot")) != NULL) {
+		freeenv(cp);
+		bootp_nfsroot = 1;
+	} else
+		bootp_nfsroot = 0;
+
 	if (error != 0) {
-#ifdef BOOTP_NFSROOT
-		panic("BOOTP call failed");
-#else
-		printf("BOOTP call failed\n");
-#endif
+		if (bootp_nfsroot)
+			panic("BOOTP call failed");
+		else
+			printf("BOOTP call failed\n");
 	}
 
 	mountopts(&nd->root_args, NULL);
@@ -1746,10 +1749,8 @@ bootpc_init(void)
 		if (bootpc_ifctx_isresolved(ifctx) != 0)
 			bootpc_decode_reply(nd, ifctx, gctx);
 
-#ifdef BOOTP_NFSROOT
-	if (gctx->gotrootpath == 0)
+	if (bootp_nfsroot && gctx->gotrootpath == 0)
 		panic("bootpc: No root path offered");
-#endif
 
 	for (ifctx = gctx->interfaces; ifctx != NULL; ifctx = ifctx->next) {
 		bootpc_adjust_interface(ifctx, gctx, td);
@@ -1795,6 +1796,8 @@ out:
 		free(ifctx, M_TEMP);
 	}
 	free(gctx, M_TEMP);
+	if (bootp_wired_to)
+		freeenv(bootp_wired_to);
 }
 
 /*
@@ -1807,27 +1810,31 @@ md_mount(struct sockaddr_in *mdsin, char *path, u_char *fhp, int *fhsizep,
     struct nfs_args *args, struct thread *td)
 {
 	struct mbuf *m;
+	char *cp;
 	int error;
 	int authunixok;
 	int authcount;
 	int authver;
 
-#ifdef BOOTP_NFSV3
-	/* First try NFS v3 */
-	/* Get port number for MOUNTD. */
-	error = krpc_portmap(mdsin, RPCPROG_MNT, RPCMNT_VER3,
-			     &mdsin->sin_port, td);
-	if (error == 0) {
-		m = xdr_string_encode(path, strlen(path));
+	if ((cp = getenv("bootp.nfsv3")) != NULL) {
+		/* First try NFS v3 */
+		/* Get port number for MOUNTD. */
+		freeenv(cp);
+		error = krpc_portmap(mdsin, RPCPROG_MNT, RPCMNT_VER3,
+		    &mdsin->sin_port, td);
+		if (error == 0) {
+			m = xdr_string_encode(path, strlen(path));
+
+			/* Do RPC to mountd. */
+			error = krpc_call(mdsin, RPCPROG_MNT, RPCMNT_VER3,
+			    RPCMNT_MOUNT, &m, NULL, td);
+		}
+		if (error == 0)
+			args->flags |= NFSMNT_NFSV3;
+	} else
+		error = 1;	/* Need to try NFS v2 */
 
-		/* Do RPC to mountd. */
-		error = krpc_call(mdsin, RPCPROG_MNT, RPCMNT_VER3,
-				  RPCMNT_MOUNT, &m, NULL, td);
-	}
-	if (error == 0) {
-		args->flags |= NFSMNT_NFSV3;
-	} else {
-#endif
+	if (error) {
 		/* Fallback to NFS v2 */
 
 		/* Get port number for MOUNTD. */
@@ -1843,10 +1850,7 @@ md_mount(struct sockaddr_in *mdsin, char *path, u_char *fhp, int *fhsizep,
 				  RPCMNT_MOUNT, &m, NULL, td);
 		if (error != 0)
 			return error;	/* message already freed */
-
-#ifdef BOOTP_NFSV3
 	}
-#endif
 
 	if (xdr_int_decode(&m, &error) != 0 || error != 0)
 		goto bad;
diff --git a/sys/nfsclient/nfs_vfsops.c b/sys/nfsclient/nfs_vfsops.c
index 9674628..ec63a7a 100644
--- a/sys/nfsclient/nfs_vfsops.c
+++ b/sys/nfsclient/nfs_vfsops.c
@@ -35,7 +35,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_bootp.h"
 #include "opt_nfsroot.h"
 
 #include <sys/param.h>
@@ -389,16 +388,23 @@ nfs_mountroot(struct mount *mp, struct thread *td)
 	struct nfsv3_diskless *nd = &nfsv3_diskless;
 	struct socket *so;
 	struct vnode *vp;
+	char *cp;
 	int error, i;
 	u_long l;
 	char buf[128];
 
 	GIANT_REQUIRED;		/* XXX until socket locking done */
 
-#if defined(BOOTP_NFSROOT) && defined(BOOTP)
-	bootpc_init();		/* use bootp to get nfs_diskless filled in */
-#elif defined(NFS_ROOT)
-	nfs_setup_diskless();
+	if ((cp = getenv("bootp")) != NULL) {
+		freeenv(cp);
+		if ((cp = getenv("bootp.nfsroot")) != NULL) {
+			freeenv(cp);
+			bootpc_init();		/* get nfs_diskless filled in */
+		}
+	}
+#if defined(NFS_ROOT)
+	if (cp == NULL)
+		nfs_setup_diskless();
 #endif
 
 	if (nfs_diskless_valid == 0)