Give loaders more control over the Forth initialization process. In

particular, allow loaders to define the name of the RC script the
interpreter needs to use. Use this new-found control to have the
PXE loader (when compiled with TFTP support and not NFS support)
read from ${bootfile}.4th, where ${bootfile} is the name of the
file fetched by the PXE firmware.

The normal startup process involves reading the following files:
1.  /boot/boot.4th
2.  /boot/loader.rc or alternatively /boot/boot.conf

When these come from a FreeBSD-defined file system, this is all
good. But when we boot over the network, subdirectories and fixed
file names are often painful to administrators and there's really
no way for them to change the behaviour of the loader.

Obtained from:	Juniper Networks, Inc.

3 files changed, 30 insertions, 1 deletions

diff --git a/sys/boot/i386/libi386/libi386.h b/sys/boot/i386/libi386/libi386.h
index f7dc379..24d6f56 100644
--- a/sys/boot/i386/libi386/libi386.h
+++ b/sys/boot/i386/libi386/libi386.h
@@ -121,4 +121,5 @@ int	bi_load32(char *args, int *howtop, int *bootdevp, vm_offset_t *bip,
 	    vm_offset_t *modulep, vm_offset_t *kernend);
 int	bi_load64(char *args, vm_offset_t *modulep, vm_offset_t *kernend);
 
+char	*pxe_default_rc(void);
 void	pxe_enable(void *pxeinfo);
diff --git a/sys/boot/i386/libi386/pxe.c b/sys/boot/i386/libi386/pxe.c
index 49814dd..93969c2 100644
--- a/sys/boot/i386/libi386/pxe.c
+++ b/sys/boot/i386/libi386/pxe.c
@@ -694,3 +694,26 @@ readudp(struct iodesc *h, void *pkt, size_t len, time_t timeout)
 	uh->uh_sport = udpread_p->s_port;
 	return udpread_p->buffer_size;
 }
+
+char *
+pxe_default_rc(void)
+{
+	char *rc;
+	size_t count, rcsz;
+
+	/* XXX It may not be a good idea to modify the PXE boot file. */
+	rc = (char *)bootplayer.bootfile;
+	rcsz = sizeof(bootplayer.bootfile);
+
+	/* Ignore how we define rc and rcsz above -- it can change. */
+	if (rcsz < 6)
+		return (NULL);
+	if (*rc == '\0') {
+		strncpy(rc, "pxeboot", rcsz);
+		rc[rcsz - 1] = '\0';
+	}
+	count = strlen(rc);
+	strncat(rc, ".4th", rcsz - count - 1);
+	printf("PXE: loading Forth from %s\n", rc);
+	return (rc);
+}
diff --git a/sys/boot/i386/loader/main.c b/sys/boot/i386/loader/main.c
index 84ae713..13f9335 100644
--- a/sys/boot/i386/loader/main.c
+++ b/sys/boot/i386/loader/main.c
@@ -192,7 +192,12 @@ main(void)
     
     bios_getsmap();
 
-    interact();			/* doesn't return */
+#ifdef LOADER_TFTP_SUPPORT
+    if (kargs->bootflags & KARGS_FLAGS_PXE)
+	interact(pxe_default_rc());
+    else
+#endif
+    interact(NULL);
 
     /* if we ever get here, it is an error */
     return (1);