Fix to make making a bootable cd possible again.

ow that the image has grown beyond the 1.44M that fits on a floppy.
(previously, the floppy emulation mode was used for cd's.)

the boot cd now uses 'no emulation mode,' where an image is provided on
the cd that is loaded and executed directly. this is the boot monitor.

in order to make this work (the entry point is the same as where the
image is loaded, and the boot monitor needs its a.out header too) and
keep compatability with the same code being used for regular booting, i
prepended 16 bytes that jumps over its header so execution can start
there.

to be able to read the CD (mostly in order to read the boot image),
boot has to use the already present 'extended read' call, but address
the CD using 2k sectors.

boot/Makefile

@@ -36,9 +36,16 @@ rawfs86.o:	rawfs.c rawfs.o
 	-cmp -s rawfs.o rawfs86.o && ln -f rawfs.o rawfs86.o
 
 boot:	boothead.s boot.o bootimage.o rawfs86.o
-	$(LD86) -o $@ \
+	$(LD86) -o bootexec \
 		boothead.s boot.o bootimage.o rawfs86.o $(LIBS)
-	install -S 8kb boot
+	install -S 12kb bootexec
+	# This is code that is executed when used on a bootable
+	# CD, as its entry point is the start of the file then.
+	# It jumps over the a.out header into the part of the
+	# code in boothead.s where the code knows it's booting
+	# from CD if entered there.
+	( printf '\xeb\x3e              ' ; cat bootexec ) >boot
+	chmod 755 boot
 
 edparams.o:	boot.c
 	ln -f boot.c edparams.c

boot/boot.c

@@ -122,6 +122,44 @@ char *bios_err(int err)
 	return "Unknown error";
 }
 
+/* CD's are addressed in 2048-byte sectors.
+ * In order to be able to read CD's but maintain the same interface of 512-byte
+ * sector addressing, we check if the device is a CD in readsectors() and if so,
+ * read it into our own buffer first 
+ */
+int readsectors(u32_t bufaddr, u32_t sector, U8_t count)
+{
+#define CDSECTOR_SIZE 2048
+	static char cdbuf[CDSECTOR_SIZE];
+	static i32_t cdbuf_sec = -1;
+	i32_t cdsec;
+
+	if(device != cddevice) {
+		return biosreadsectors(bufaddr, sector, count);
+	}
+
+	while(count > 0) {
+		u32_t offset;
+#define FACTOR (CDSECTOR_SIZE/SECTOR_SIZE)
+		cdsec = sector / FACTOR;
+		offset = (sector % FACTOR) * SECTOR_SIZE;
+		if(cdsec != cdbuf_sec) {
+			int r;
+			if((r=biosreadsectors(mon2abs(cdbuf), cdsec, 1)) != 0) {
+				printf("error %d\n", r);
+				return r;
+			}
+			cdbuf_sec = cdsec;
+		}
+		raw_copy(bufaddr, mon2abs(cdbuf) + offset, SECTOR_SIZE);
+		bufaddr += SECTOR_SIZE;
+		count--;
+		sector++;
+	}
+
+	return 0;
+}
+
 char *unix_err(int err)
 /* Translate the few errors rawfs can give. */
 {
@@ -515,6 +553,12 @@ void initialize(void)
 	}
 #endif
 
+	/* If we were booted from CD, remember what device it was. */
+	if(cdbooted)
+		cddevice = device;
+	else
+		cddevice = 0xff;	/* Invalid. */
+
 	/* Set the new caddr for relocate. */
 	caddr= newaddr;
 
@@ -564,6 +608,14 @@ void initialize(void)
 			readerr(masterpos, r); exit(1);
 		}
 
+		/* If we're a CD, we know what we want. */
+		if(device == cddevice) {
+			p = 1;	/* We know this is the root FS. */
+			lowsec = table[p]->lowsec;
+			bootdev.primary = p;
+			break;	/* Found! */
+		}
+
 		/* See if you can find "lowsec" back. */
 		for (p= 0; p < NR_PARTITIONS; p++) {
 			if (lowsec - table[p]->lowsec < table[p]->size) break;
@@ -590,12 +642,17 @@ void initialize(void)
 		bootdev.primary= p;
 		masterpos= table[p]->lowsec;
 	}
-	strcpy(bootdev.name, "d0p0");
+
-	bootdev.name[1] += (device - 0x80);
+	if(device == cddevice) {
-	bootdev.name[3] += bootdev.primary;
+		strcpy(bootdev.name, CDNAME);
-	if (bootdev.secondary >= 0) {
+	} else {
-		strcat(bootdev.name, "s0");
+		strcpy(bootdev.name, "d0p0");
-		bootdev.name[5] += bootdev.secondary;
+		bootdev.name[1] += (device - 0x80);
+		bootdev.name[3] += bootdev.primary;
+		if (bootdev.secondary >= 0) {
+			strcat(bootdev.name, "s0");
+			bootdev.name[5] += bootdev.secondary;
+		}
 	}
 
 	/* Find out about the video hardware. */
@@ -1087,7 +1144,7 @@ dev_t name2dev(char *name)
 	n= name;
 	if (strncmp(n, "/dev/", 5) == 0) n+= 5;
 
-	if (strcmp(n, "ram") == 0) {
+	if (strcmp(n, "ram") == 0 || strcmp(n, CDNAME) == 0) {
 		dev= DEV_RAM;
 	} else
 	if (n[0] == 'f' && n[1] == 'd' && numeric(n+2)) {
@@ -1879,7 +1936,6 @@ void monitor(void)
 void boot(void)
 /* Load Minix and start it, among other things. */
 {
-
 	/* Initialize tables. */
 	initialize();
 
@@ -1928,8 +1984,7 @@ void main(int argc, char **argv)
 		fatal(bootdev.name);
 
 	/* Check if it is a bootable Minix device. */
-	if (readsectors(mon2abs(bootcode), lowsec, 1) != 0
+	if (readsectors(mon2abs(bootcode), lowsec, 1) != 0) {
-		|| memcmp(bootcode, boot_magic, sizeof(boot_magic)) != 0) {
 		fprintf(stderr, "edparams: %s: not a bootable Minix device\n",
 			bootdev.name);
 		exit(1);

boot/boot.h

@@ -58,6 +58,9 @@ EXTERN u32_t caddr, daddr;	/* Code and data address of the boot program. */
 EXTERN u32_t runsize;		/* Size of this program. */
 
 EXTERN u16_t device;		/* Drive being booted from. */
+EXTERN u16_t cddevice;		/* Drive that is CD if known. */
+
+#define CDNAME	"cd"		/* Name of the CD device. */
 
 typedef struct {		/* One chunk of free memory. */
 	u32_t	base;		/* Start byte. */
@@ -66,6 +69,7 @@ typedef struct {		/* One chunk of free memory. */
 
 EXTERN memory mem[3];		/* List of available memory. */
 EXTERN int mon_return;		/* Monitor stays in memory? */
+EXTERN int cdbooted;		/* Did we boot from CD? (Set by boothead.s.) */
 
 typedef struct bios_env
 {
@@ -101,6 +105,9 @@ int readsectors(u32_t bufaddr, u32_t sector, U8_t count);
 			/* Read 1 or more sectors from "device". */
 int writesectors(u32_t bufaddr, u32_t sector, U8_t count);
 			/* Write 1 or more sectors to "device". */
+
+int biosreadsectors(u32_t bufaddr, u32_t sector, U8_t count);
+
 int getch(void);
 			/* Read a keypress. */
 void scan_keyboard(void);	

boot/boothead.s

@@ -41,19 +41,30 @@
 .extern _rem_part				! To pass partition info
 .extern _k_flags				! Special kernel flags
 .extern _mem					! Free memory list
+.extern _cdbooted				! Whether we booted from CD
+.extern _cddevice				! Whether we booted from CD
 
 .text
 
-! Set segment registers and stack pointer using the programs own header!
+! We assume boot is always linked with a short (32 byte) a.out header and has
-! The header is either 32 bytes (short form) or 48 bytes (long form).  The
+! 16 bytes of its own prefix, so 48 bytes to skip. bootblock jumps into us
-! bootblock will jump to address 0x10030 in both cases, calling one of the
+! at offset 0x30, cd boot code at 0x40
-! two jmpf instructions below.
 
-	jmpf	boot, LOADSEG+3	! Set cs right (skipping long a.out header)
+	! Set cs right
-	.space	11		! jmpf + 11 = 16 bytes
+	! (skip short a.out header plus 16 byte preefix)
-	jmpf	boot, LOADSEG+2	! Set cs right (skipping short a.out header)
+	jmpf	boot, LOADSEG+3		
+	.space	11
+
+	! entry point when booting from CD
+	jmpf	cdboot, LOADSEG+3
+	.space	11
+cdboot:
+	mov	bx, #1
+	jmp	commonboot
 boot:
-	mov	ax, #LOADSEG
+	mov	bx, #0
+commonboot:
+	mov	ax, #LOADSEG+1
 	mov	ds, ax		! ds = header
 
 	movb	al, a_flags
@@ -96,6 +107,7 @@ sepID:
 	mov	_device, dx	! Boot device (probably 0x00 or 0x80)
 	mov	_rem_part+0, si	! Remote partition table offset
 	pop	_rem_part+2	! and segment (saved es)
+	mov	_cdbooted, bx	! Booted from CD? (bx set above)
 
 ! Remember the current video mode for restoration on exit.
 	movb	ah, #0x0F	! Get current video mode
@@ -117,7 +129,7 @@ sepID:
 	mov	_daddr+0, ax
 	mov	_daddr+2, dx
 	push	ds
-	mov	ax, #LOADSEG
+	mov	ax, #LOADSEG+1
 	mov	ds, ax		! Back to the header once more
 	mov	ax, a_total+0
 	mov	dx, a_total+2	! dx:ax = data + bss + heap + stack
@@ -416,6 +428,8 @@ _dev_open:
 	push	es
 	push	di		! Save registers used by BIOS calls
 	movb	dl, _device	! The default device
+	cmpb	dl, _cddevice
+	je	cdopen
 	cmpb	dl, #0x80	! Floppy < 0x80, winchester >= 0x80
 	jae	winchester
 floppy:
@@ -463,6 +477,10 @@ winchester:
 	jc	geoerr		! No such drive?
 	andb	cl, #0x3F	! cl = max sector number (1-origin)
 	incb	dh		! dh = 1 + max head number (0-origin)
+	jmp geoboth
+cdopen:
+	movb	cl, #0x3F	! Think up geometry for CD's
+	movb	dh, #0x2
 geoboth:
 	movb	sectors, cl	! Sectors per track
 	movb	al, cl		! al = sectors per track
@@ -515,20 +533,20 @@ _dev_boundary:
 	neg	ax		! ax = (sector % sectors) == 0
 	ret
 
-! int readsectors(u32_t bufaddr, u32_t sector, u8_t count)
+! int biosreadsectors(u32_t bufaddr, u32_t sector, u8_t count)
 ! int writesectors(u32_t bufaddr, u32_t sector, u8_t count)
 !	Read/write several sectors from/to disk or floppy.  The buffer must
 !	be between 64K boundaries!  Count must fit in a byte.  The external
 !	variables _device, sectors and secspcyl describe the disk and its
 !	geometry.  Returns 0 for success, otherwise the BIOS error code.
 !
-.define _readsectors, _writesectors
+.define _biosreadsectors, _writesectors
 _writesectors:
 	push	bp
 	mov	bp, sp
 	movb	13(bp), #0x03	! Code for a disk write
 	jmp	rwsec
-_readsectors:
+_biosreadsectors:
 	push	bp
 	mov	bp, sp
 	movb	13(bp), #0x02	! Code for a disk read
@@ -555,6 +573,9 @@ more:	mov	ax, 8(bp)
 	mov	dx, 10(bp)	! dx:ax = abs sector.  Divide it by sectors/cyl
 	cmp	dx, #[1024*255*63-255]>>16  ! Near 8G limit?
 	jae	bigdisk
+	mov	si, _device	
+	cmp	si, _cddevice	! Is it a CD?
+	je	bigdisk		! CD's need extended read.
 	div	secspcyl	! ax = cylinder, dx = sector within cylinder
 	xchg	ax, dx		! ax = sector within cylinder, dx = cylinder
 	movb	ch, dl		! ch = low 8 bits of cylinder
@@ -1512,5 +1533,3 @@ p_mcs_desc:
 	.comm	bus, 2		! Saved return value of _get_bus
 	.comm	unchar, 2	! Char returned by ungetch(c)
 	.comm	line, 2		! Serial line I/O port to copy console I/O to.
-
-

boot/installboot.c

@@ -496,7 +496,8 @@ void make_bootable(enum howto how, char *device, char *bootblock,
 			boothdr.a_magic[0]= !A_MAGIC0;
 		} else {
 			readblock(addr, buf, block_size);
-			memcpy(&boothdr, buf, sizeof(struct exec));
+			/* Must skip 16 bytes of 'boot' as that contains code. */
+			memcpy(&boothdr, buf + 16, sizeof(struct exec));
 		}
 		bootf= nil;
 		dummy.process= boothdr;

commands/simple/writeisofs.c

@@ -108,6 +108,7 @@ struct bc_validation {
 
 #define INDICATE_BOOTABLE	0x88
 
+#define BOOTMEDIA_UNSPECIFIED	-1
 #define BOOTMEDIA_NONE		0
 #define BOOTMEDIA_120M		1
 #define BOOTMEDIA_144M		2
@@ -160,7 +161,8 @@ struct node {
 };
 
 int n_reserved_pathtableentries = 0, n_used_pathtableentries = 0;
-int harddisk_emulation = 0;
+int bootmedia = BOOTMEDIA_UNSPECIFIED;
+unsigned long bootseg = 0;
 int system_type = 0;
 
 int get_system_type(int fd);
@@ -736,15 +738,17 @@ writebootcatalog(int fd, int  *currentsector, int imagesector, int imagesectors)
 	memset(&initial, 0, sizeof(initial));
 
 	initial.indicator = INDICATE_BOOTABLE;
-	if (harddisk_emulation)
+	initial.media = bootmedia;
+	initial.seg = (u_int16_t) (bootseg & 0xFFFF);
+	initial.sectors = 1;
+	if (bootmedia == BOOTMEDIA_HARDDISK)
 	{
-		initial.media = BOOTMEDIA_HARDDISK;
 		initial.type = system_type;
 	}
-	else
+	if (bootmedia == BOOTMEDIA_NONE)
-		initial.media = BOOTMEDIA_144M;
+	{
-	/* initial.sectors = imagesectors; */
+		initial.sectors = imagesectors;
-	initial.sectors = 1;
+	}
 	initial.startsector = imagesector;
 
 	written += Write(fd, &initial, sizeof(initial));
@@ -857,10 +861,24 @@ main(int argc, char *argv[])
 		return 1;
 	}
 
-	while ((ch = getopt(argc, argv, "Rb:hl:")) != -1) {
+	while ((ch = getopt(argc, argv, "b:s:Rb:hl:nf")) != -1) {
 		switch(ch) {
+			case 's':
+				if(optarg[0] != '0' || optarg[1] != 'x') {
+					fprintf(stderr, "%s: -s<hex>\n",
+						argv[0]);
+					return 1;
+				}
+				bootseg = strtoul(optarg+2, NULL, 16);
+				break;
 			case 'h':
-				harddisk_emulation= 1;
+				bootmedia= BOOTMEDIA_HARDDISK;
+				break;
+			case 'n':
+				bootmedia= BOOTMEDIA_NONE;
+				break;
+			case 'f':
+				bootmedia= BOOTMEDIA_144M;
 				break;
 			case 'l':
 				label = optarg;
@@ -881,8 +899,23 @@ main(int argc, char *argv[])
 	argc -= optind;
 	argv += optind;
 
+	/* Args check */
+
 	if(argc != 2) {
-		fprintf(stderr, "usage: %s [-l <label>] [-b <bootfloppyimage>] <dir> <isofile>\n",
+		fprintf(stderr, "usage: %s [-l <label>] [-b <bootimage> [-n] [-f] [-h] [-s <bootsegment>] ] <dir> <isofile>\n",
+			prog);
+		return 1;
+	}
+
+	if((bootimage && bootmedia == BOOTMEDIA_UNSPECIFIED) ||
+		(!bootimage && bootmedia != BOOTMEDIA_UNSPECIFIED)) {
+		fprintf(stderr, "%s: provide both boot image and boot type or neither.\n",
+			prog);
+		return 1;
+	}
+
+	if(!bootimage && bootseg) {
+		fprintf(stderr, "%s: boot seg provided but no boot image\n",
 			prog);
 		return 1;
 	}
@@ -971,9 +1004,9 @@ main(int argc, char *argv[])
 		/* write the boot catalog */
 		fprintf(stderr, " * writing the boot catalog\n");
 		bootcatalogsector = currentsector;
-		if (harddisk_emulation)
+		if (bootmedia == BOOTMEDIA_HARDDISK)
 			system_type = get_system_type(bootfd);
-		writebootcatalog(fd, &currentsector, imagesector, imagesectors);
+		writebootcatalog(fd, &currentsector, 0, 0);
 
 		/* write boot image */
 		fprintf(stderr, " * writing the boot image\n");

tools/mkboot

@@ -9,10 +9,10 @@ mdec=/usr/mdec	# bootstraps
 
 # Check arguments.
 case "$#:$1" in
-1:bootable | 1:hdboot | [12]:fdboot | [123]:cdfdboot )
+1:bootable | 1:hdboot | [12]:fdboot )
 	action=$1 dev=$2 size=$3
 	;;
-*)	echo "Usage: $0 [bootable | hdboot | fdboot [device]] | cdfdboot [device [size]]" >&2
+*)	echo "Usage: $0 [bootable | hdboot | fdboot [device]]" >&2
 	exit 1
 esac
 
@@ -161,53 +161,6 @@ fdboot)
 	edparams $dev 'main(){delay 2000;boot}; save' || exit
 	echo "Test kernel installed on $dev"
 	;;
-
-cdfdboot)
-	# cdfdboot: Make a boot floppy image to go on a CD for booting from.
-	if [ -z "$dev" ]
-	then
-		ramdisk `expr 1440 \* 1024` 2>/dev/null
-		dev=/dev/ram
-	fi
-	if [ -z "$size" ]
-	then
-		size=1440
-	fi
-	umount $dev 2>/dev/null
-	if mkfs -B 1024 -b $size -i 512 $dev || exit 1
-	then :
-	else
-		echo "mkfs of $dev failed."
-		exit 1;
-	fi
-
-	# Install /dev, /boot
-	mount $dev /mnt || exit 1
-	mkdir /mnt/dev
-	mkdir /mnt/boot
-	mkdir /mnt/boot/image
-	( cd /mnt/dev && sh /usr/src/commands/scripts/MAKEDEV.sh std )
-	cp -p image /mnt/boot/image || exit 1
-	cp -p ../boot/boot /mnt/boot/boot || exit 1
-	umount $dev || exit 1
-	installboot -d $dev ../boot/bootblock boot/boot || exit 1
-	edparams $dev '
-unset bootopts;
-unset servers;
-unset rootdev;
-unset leader;
-unset image;
-disable=inet;
-bootcd=1;
-cdproberoot=1;
-ata_id_timeout=2;
-bootbig(1, Regular MINIX 3) { unset image; boot }
-leader() { echo \n--- Welcome to MINIX 3. This is the boot monitor. ---\n\nChoose an option from the menu or press ESC if you need to do anything special.\nOtherwise I will boot with my defaults in 10 seconds.\n\n };
-main(){trap 10000 boot; menu; };
-save' || exit
-
-	# copy image
-	dd if=$dev of=cdfdimage bs=1024 count=$size
 esac
 sync
 exit 0

tools/release.sh

@@ -107,7 +107,7 @@ usr=/dev/c0d7p0s2
 RELEASEDIR=/usr/r
 RELEASEPACKAGE=${RELEASEDIR}/usr/install/packages
 RELEASEPACKAGESOURCES=${RELEASEDIR}/usr/install/package-sources
-IMAGE=cdfdimage
+IMAGE=../boot/boot
 ROOTIMAGE=rootimage
 CDFILES=/usr/tmp/cdreleasefiles
 sh tell_config OS_RELEASE . OS_VERSION >/tmp/rel.$$
@@ -210,7 +210,7 @@ then
 fi
 
 echo " * Cleanup old files"
-rm -rf $RELEASEDIR $IMG $IMAGE $ROOTIMAGE $CDFILES image*
+rm -rf $RELEASEDIR $IMG $ROOTIMAGE $CDFILES image*
 mkdir -p $CDFILES || exit
 mkdir -p $RELEASEDIR
 mkfs -i 2000 -B $BS -b $ROOTBLOCKS $TMPDISK3 || exit
@@ -288,18 +288,20 @@ then
 #define _SVN_REVISION \"$REVTAG\"
 #endif" >>$RELEASEDIR/usr/src/include/minix/sys_config.h
 
+# output image name
+if [ "$USB" -ne 0 ]; then
+	IMG=${IMG_BASE}_${REVTAG}.img
+else
+	IMG=${IMG_BASE}_${REVTAG}.iso
+fi
+
 else
 	( cd .. && make depend && make clean )
 	srcdir=/usr/$SRC
 	( cd $srcdir && tar cf - . ) | ( cd $RELEASEDIR/usr && mkdir $SRC && cd $SRC && tar xf - )
 	REVTAG=copy
 	REVISION=unknown
-fi
+	IMG=${IMG_BASE}_copy.iso
-
-if [ "$USB" -ne 0 ]; then
-	IMG=${IMG_BASE}_${REVTAG}.img
-else
-	IMG=${IMG_BASE}_${REVTAG}.iso
 fi
 
 echo " * Fixups for owners and modes of dirs and files"
@@ -354,26 +356,37 @@ umount $TMPDISK1 || exit
 umount $TMPDISK2 || exit
 umount $TMPDISK3 || exit
 
+# Boot monitor variables for boot CD
+edparams $TMPDISK3 'unset bootopts;
+unset servers;
+unset rootdev;
+unset leader;
+unset image;
+disable=inet;
+bootcd=1;
+cdproberoot=1;
+ata_id_timeout=2;
+bootbig(1, Regular MINIX 3) { unset image; boot }
+leader() { echo \n--- Welcome to MINIX 3. This is the boot monitor. ---\n\nChoose an option from the menu or press ESC if you need to do anything special.\nOtherwise I will boot with my defaults in 10 seconds.\n\n }; main(){trap 10000 boot; menu; };
+save' 
+
 (cd ../boot && make)
 dd if=$TMPDISK3 of=$ROOTIMAGE bs=$BS count=$ROOTBLOCKS
-sh mkboot cdfdboot $TMPDISK3 $ROOTKB
-# image no longer fits on a floppy
-#cp $IMAGE $CDFILES/bootflop.img
 cp release/cd/* $CDFILES || true
 echo "This is Minix version $version_pretty prepared `date`." >$CDFILES/VERSION.TXT
 
-h_opt=
+boottype=-n
 bootimage=$IMAGE
 if [ "$HDEMU" -ne 0 ]; then
 	make_hdimage
-	h_opt='-h'
+	boottype='-h'
 	bootimage=hdimage
 fi
 
 if [ "$USB" -ne 0 ]; then
 	mv $bootimage $IMG
 else
-	writeisofs -l MINIX -b $bootimage $h_opt $CDFILES $IMG || exit 1
+	writeisofs -s0x1000 -l MINIX -b $bootimage $boottype $CDFILES $IMG || exit 1
 
 	if [ "$HDEMU" -eq 0 ]
 	then