m68k: fixup_next_boot_floppy tool (actually writes the disklabel)

Next floppies actually do have a "disk label" (partitionning scheme),
the boot block being later on the disk.

This commit generates an identical label to the image I have here (but
not the copies at other sectors), including the checksum.

Change-Id: I7f939c26e70e3626d9af7a3eb342cfd32c298e3d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3098
Reviewed-by: Alex von Gluck IV <[email protected]>

src/tools/Jamfile

@@ -95,6 +95,7 @@ SubInclude HAIKU_TOP src tools cppunit ;
 SubInclude HAIKU_TOP src tools create_repository_config ;
 SubInclude HAIKU_TOP src tools elfsymbolpatcher ;
 SubInclude HAIKU_TOP src tools fixup_amiga_boot_checksum ;
+SubInclude HAIKU_TOP src tools fixup_next_boot_floppy ;
 SubInclude HAIKU_TOP src tools fixup_tos_boot_checksum ;
 SubInclude HAIKU_TOP src tools fs_shell ;
 SubInclude HAIKU_TOP src tools gensyscalls ;

src/tools/fixup_next_boot_floppy/Jamfile

@@ -0,0 +1,16 @@
+SubDir HAIKU_TOP src tools fixup_next_boot_floppy ;
+
+#UseHeaders [ FDirName $(HAIKU_TOP) headers build ] : true ;
+
+#if ! $(HOST_PLATFORM_HAIKU_COMPATIBLE) {
+#	UseHeaders [ FDirName $(HAIKU_TOP) headers build os ] : true ;
+#	UseHeaders [ FDirName $(HAIKU_TOP) headers build os support ] : true ;
+#}
+
+#UsePrivateHeaders kernel ;
+UseHeaders [ FDirName $(HAIKU_TOP) headers private kernel platform next_m68k ] : true ;
+
+BuildPlatformMain <build>fixup_next_boot_floppy
+	: fixup_next_boot_floppy.c
+	:
+;

src/tools/fixup_next_boot_floppy/fixup_next_boot_floppy.c

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2020, François Revol, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+
+#include <disklabel.h>
+
+/* for now we actually write all of the disk label here. */
+
+//#define DL_SIZE (sizeof(disklabel))
+#define DL_SIZE (offsetof(struct disk_label, dl_un.DL_v3_checksum) + sizeof(uint16_t))
+#define SUM_CNT (offsetof(struct disk_label, dl_un.DL_v3_checksum) / sizeof(uint16_t))
+
+// could not get ByteOrder.h to include
+#define H2B32 htonl
+#define H2B16 htons
+#define B2H16 ntohs
+
+// see https://unix.superglobalmegacorp.com/darwin01/newsrc/machdep/i386/checksum_16.c.html
+static uint16_t checksum_16(uint16_t *p, int count)
+{
+	uint32_t sum = 0;
+	for (;count--;)
+		sum += B2H16(*p++);
+	// sum both shorts
+	sum = (sum & 0x0ffff) + (sum >> 16);
+	if (sum > 65535)
+		sum -= 65535;
+	return sum;
+}
+
+int main(int argc, char **argv)
+{
+	int fd;
+	unsigned int i;
+	uint16_t sum;
+	struct disk_label disklabel = {
+		H2B32(DL_V3),
+		H2B32(0),
+		H2B32(0),
+		"NextBoot",//"HaikuBoot",
+		H2B32(0),
+		H2B32(0xa991637a), //H2B32(0x4841494b), // dl_tag: 'HAIK'
+		"Sony MPX-111N 2880-512", // same as NS image, not sure it matters
+		"removable_rw_floppy",
+		H2B32(1024), // !! 1024 bytes / sector !!
+		H2B32(2),
+		H2B32(9),
+		H2B32(80),
+		H2B32(300),
+		H2B16(96),
+		H2B16(0),
+		H2B16(0),
+		H2B16(0),
+		H2B16(0),
+		H2B16(0),
+		H2B32(0x20),H2B32(0xffffffff),	// boot block locations XXX: move it closer to start?
+		"fdmach", //"haiku_loader",
+		"silly", //"schredder",
+		'a', 'b',
+		// partitions
+		{
+			// Nextstep uses this:
+			{ H2B32(0), H2B32(0x540), H2B16(0x2000), H2B16(0x400), 't', H2B16(0x20), H2B16(0x800), 0, 1, "", 1, "4.3BSD"},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""},
+			{ H2B32(-1), H2B32(-1), H2B16(-1), H2B16(-1), 0, H2B16(-1), H2B16(-1), -1, 0, "", 0, ""}
+		}
+	};
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		return 1;
+	}
+	//XXX: implement support simple checksum of existing label?
+	/*
+	if (read(fd, bootblock, DL_SIZE) < DL_SIZE) {
+		perror("read");
+		return 1;
+	}
+	*/
+	sum = checksum_16((uint16_t *)&disklabel, SUM_CNT);
+	fprintf(stderr, "checksum: 0x%04x\n", sum);
+	disklabel.dl_un.DL_v3_checksum = H2B16(sum);
+	lseek(fd, 0LL, SEEK_SET);
+	write(fd, &disklabel, DL_SIZE);
+	return 0;
+}