gptboot.c revision 92225 
1/*
2 * Copyright (c) 1998 Robert Nordier
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are freely
6 * permitted provided that the above copyright notice and this
7 * paragraph and the following disclaimer are duplicated in all
8 * such forms.
9 *
10 * This software is provided "AS IS" and without any express or
11 * implied warranties, including, without limitation, the implied
12 * warranties of merchantability and fitness for a particular
13 * purpose.
14 */
15
16/*
17 * $FreeBSD: head/sys/boot/i386/gptboot/gptboot.c 92225 2002-03-13 11:03:36Z ru $
18 */
19
20#include <sys/param.h>
21#include <sys/reboot.h>
22#include <sys/diskslice.h>
23#include <sys/disklabel.h>
24#include <sys/dirent.h>
25#include <machine/bootinfo.h>
26#include <machine/elf.h>
27
28#include <ufs/ffs/fs.h>
29#include <ufs/ufs/dinode.h>
30
31#include <stdarg.h>
32
33#include <a.out.h>
34
35#include <btxv86.h>
36
37#include "boot2.h"
38#include "lib.h"
39
40#define RBX_ASKNAME	0x0	/* -a */
41#define RBX_SINGLE	0x1	/* -s */
42#define RBX_DFLTROOT	0x5	/* -r */
43#define RBX_KDB 	0x6	/* -d */
44#define RBX_CONFIG	0xa	/* -c */
45#define RBX_VERBOSE	0xb	/* -v */
46#define RBX_SERIAL	0xc	/* -h */
47#define RBX_CDROM	0xd	/* -C */
48#define RBX_GDB 	0xf	/* -g */
49#define RBX_MUTE	0x10	/* -m */
50#define RBX_PAUSE	0x12	/* -p */
51#define RBX_DUAL	0x1d	/* -D */
52#define RBX_PROBEKBD	0x1e	/* -P */
53
54#define RBX_MASK	0x2005ffff
55
56#define PATH_CONFIG	"/boot.config"
57#define PATH_BOOT3	"/boot/loader"
58#define PATH_KERNEL	"/kernel"
59
60#define ARGS		0x900
61#define NOPT		13
62#define NDEV		5
63#define MEM_BASE	0x12
64#define MEM_EXT 	0x15
65#define V86_CY(x)	((x) & 1)
66#define V86_ZR(x)	((x) & 0x40)
67
68/*
69 * We use 4k `virtual' blocks for filesystem data, whatever the actual
70 * filesystem block size. FFS blocks are always a multiple of 4k.
71 */
72#define VBLKSIZE	4096
73#define VBLKMASK	(VBLKSIZE - 1)
74#define DBPERVBLK	(VBLKSIZE / DEV_BSIZE)
75#define IPERVBLK	(VBLKSIZE / sizeof(struct dinode))
76#define INDIRPERVBLK	(VBLKSIZE / sizeof(ufs_daddr_t))
77#define INO_TO_VBA(fs, x) (fsbtodb(fs, ino_to_fsba(fs, x)) + \
78    (ino_to_fsbo(fs, x) / IPERVBLK) * DBPERVBLK)
79#define INO_TO_VBO(fs, x) (ino_to_fsbo(fs, x) % IPERVBLK)
80#define FS_TO_VBA(fs, fsb, off) (fsbtodb(fs, fsb) + \
81    ((off) / VBLKSIZE) * DBPERVBLK)
82#define FS_TO_VBO(fs, fsb, off) ((off) & VBLKMASK)
83
84#define DRV_HARD	0x80
85#define DRV_MASK	0x7f
86
87#define TYPE_AD		0
88#define TYPE_WD		1
89#define TYPE_WFD 	2
90#define TYPE_FD		3
91#define TYPE_DA		4
92
93/* Buffers that must not span a 64k boundary. */
94static struct dmadat {
95	char blkbuf[VBLKSIZE];				/* filesystem blocks */
96	ufs_daddr_t indbuf[VBLKSIZE / sizeof(ufs_daddr_t)]; /* indir blocks */
97	char sbbuf[SBSIZE];				/* superblock */
98	char secbuf[DEV_BSIZE];				/* for MBR/disklabel */
99} *dmadat;
100
101extern uint32_t _end;
102
103static const char optstr[NOPT] = "DhaCcdgmPprsv";
104static const unsigned char flags[NOPT] = {
105    RBX_DUAL,
106    RBX_SERIAL,
107    RBX_ASKNAME,
108    RBX_CDROM,
109    RBX_CONFIG,
110    RBX_KDB,
111    RBX_GDB,
112    RBX_MUTE,
113    RBX_PROBEKBD,
114    RBX_PAUSE,
115    RBX_DFLTROOT,
116    RBX_SINGLE,
117    RBX_VERBOSE
118};
119
120static const char *const dev_nm[] = {"ad", "wd", "  ", "fd", "da"};
121static const unsigned dev_maj[] = {30, 0, 1, 2, 4};
122
123static struct dsk {
124    unsigned drive;
125    unsigned type;
126    unsigned unit;
127    unsigned slice;
128    unsigned part;
129    unsigned start;
130    int init;
131    int meta;
132} dsk;
133static char cmd[512];
134static char kname[1024];
135static uint32_t opts;
136static struct bootinfo bootinfo;
137static int ls;
138static uint32_t fs_off;
139static uint8_t ioctrl = 0x1;
140
141void exit(int);
142static void load(const char *);
143static int parse(char *);
144static ino_t lookup(const char *);
145static int xfsread(ino_t, void *, size_t);
146static ssize_t fsread(ino_t, void *, size_t);
147static int dskread(void *, unsigned, unsigned);
148static int printf(const char *,...);
149static int putchar(int);
150static void *memcpy(void *, const void *, size_t);
151static uint32_t memsize(int);
152static int drvread(void *, unsigned, unsigned);
153static int keyhit(unsigned);
154static int xputc(int);
155static int xgetc(int);
156static int getc(int);
157
158static inline void
159readfile(const char *fname, void *buf, size_t size)
160{
161    ino_t ino;
162
163    if ((ino = lookup(fname)))
164	fsread(ino, buf, size);
165}
166
167static inline int
168strcmp(const char *s1, const char *s2)
169{
170    for (; *s1 == *s2 && *s1; s1++, s2++);
171    return (u_char)*s1 - (u_char)*s2;
172}
173
174static inline int
175fsfind(const char *name, ino_t * ino)
176{
177    char buf[DEV_BSIZE];
178    struct dirent *d;
179    char *s;
180    ssize_t n;
181
182    fs_off = 0;
183    while ((n = fsread(*ino, buf, DEV_BSIZE)) > 0)
184	for (s = buf; s < buf + DEV_BSIZE;) {
185	    d = (void *)s;
186	    if (ls)
187		printf("%s ", d->d_name);
188	    else if (!strcmp(name, d->d_name)) {
189		*ino = d->d_fileno;
190		return d->d_type;
191	    }
192	    s += d->d_reclen;
193	}
194    if (n != -1 && ls)
195	putchar('\n');
196    return 0;
197}
198
199static inline int
200getchar(void)
201{
202    int c;
203
204    c = xgetc(0);
205    if (c == '\r')
206	c = '\n';
207    return c;
208}
209
210static inline void
211getstr(char *str, int size)
212{
213    char *s;
214    int c;
215
216    s = str;
217    do {
218	switch (c = getchar()) {
219	case 0:
220	    break;
221	case '\b':
222	case '\177':
223	    if (s > str) {
224		s--;
225		putchar('\b');
226		putchar(' ');
227	    } else
228		c = 0;
229	    break;
230	case '\n':
231	    *s = 0;
232	    break;
233	default:
234	    if (s - str < size - 1)
235		*s++ = c;
236	}
237	if (c)
238	    putchar(c);
239    } while (c != '\n');
240}
241
242static inline uint32_t
243drvinfo(int drive)
244{
245    v86.addr = 0x13;
246    v86.eax = 0x800;
247    v86.edx = DRV_HARD + drive;
248    v86int();
249    if (V86_CY(v86.efl))
250	return 0x4f010f;
251    return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
252	   (v86.edx & 0xff00) | (v86.ecx & 0x3f);
253}
254
255static inline void
256putc(int c)
257{
258    v86.addr = 0x10;
259    v86.eax = 0xe00 | (c & 0xff);
260    v86.ebx = 0x7;
261    v86int();
262}
263
264int
265main(void)
266{
267    int autoboot, i;
268
269    dmadat = (void *)(roundup2(__base + _end, 0x10000) - __base);
270    v86.ctl = V86_FLAGS;
271    dsk.drive = *(uint8_t *)PTOV(ARGS);
272    dsk.type = dsk.drive & DRV_HARD ? TYPE_AD : TYPE_FD;
273    dsk.unit = dsk.drive & DRV_MASK;
274    dsk.slice = *(uint8_t *)PTOV(ARGS + 1) + 1;
275    bootinfo.bi_version = BOOTINFO_VERSION;
276    bootinfo.bi_size = sizeof(bootinfo);
277    bootinfo.bi_basemem = memsize(MEM_BASE);
278    bootinfo.bi_extmem = memsize(MEM_EXT);
279    bootinfo.bi_memsizes_valid++;
280    for (i = 0; i < N_BIOS_GEOM; i++)
281	bootinfo.bi_bios_geom[i] = drvinfo(i);
282    autoboot = 2;
283    readfile(PATH_CONFIG, cmd, sizeof(cmd));
284    if (*cmd) {
285	printf("%s: %s", PATH_CONFIG, cmd);
286	if (parse(cmd))
287	    autoboot = 0;
288	*cmd = 0;
289    }
290    if (autoboot && !*kname) {
291	if (autoboot == 2) {
292	    memcpy(kname, PATH_BOOT3, sizeof(PATH_BOOT3));
293	    if (!keyhit(0x37)) {
294		load(kname);
295		autoboot = 1;
296	    }
297	}
298	if (autoboot == 1)
299	    memcpy(kname, PATH_KERNEL, sizeof(PATH_KERNEL));
300    }
301    for (;;) {
302	printf(" \n>> FreeBSD/i386 BOOT\n"
303	       "Default: %u:%s(%u,%c)%s\n"
304	       "boot: ",
305	       dsk.drive & DRV_MASK, dev_nm[dsk.type], dsk.unit,
306	       'a' + dsk.part, kname);
307	if (ioctrl & 0x2)
308	    sio_flush();
309	if (!autoboot || keyhit(0x5a))
310	    getstr(cmd, sizeof(cmd));
311	else
312	    putchar('\n');
313	autoboot = 0;
314	if (parse(cmd))
315	    putchar('\a');
316	else
317	    load(kname);
318    }
319}
320
321/* XXX - Needed for btxld to link the boot2 binary; do not remove. */
322void
323exit(int x)
324{
325}
326
327static void
328load(const char *fname)
329{
330    union {
331	struct exec ex;
332	Elf32_Ehdr eh;
333    } hdr;
334    Elf32_Phdr ep[2];
335    Elf32_Shdr es[2];
336    caddr_t p;
337    ino_t ino;
338    uint32_t addr, x;
339    int fmt, i, j;
340
341    if (!(ino = lookup(fname))) {
342	if (!ls)
343	    printf("No %s\n", fname);
344	return;
345    }
346    if (xfsread(ino, &hdr, sizeof(hdr)))
347	return;
348    if (N_GETMAGIC(hdr.ex) == ZMAGIC)
349	fmt = 0;
350    else if (IS_ELF(hdr.eh))
351	fmt = 1;
352    else {
353	printf("Invalid %s\n", "format");
354	return;
355    }
356    if (fmt == 0) {
357	addr = hdr.ex.a_entry & 0xffffff;
358	p = PTOV(addr);
359	fs_off = PAGE_SIZE;
360	if (xfsread(ino, p, hdr.ex.a_text))
361	    return;
362	p += roundup2(hdr.ex.a_text, PAGE_SIZE);
363	if (xfsread(ino, p, hdr.ex.a_data))
364	    return;
365	p += hdr.ex.a_data + roundup2(hdr.ex.a_bss, PAGE_SIZE);
366	bootinfo.bi_symtab = VTOP(p);
367	memcpy(p, &hdr.ex.a_syms, sizeof(hdr.ex.a_syms));
368	p += sizeof(hdr.ex.a_syms);
369	if (hdr.ex.a_syms) {
370	    if (xfsread(ino, p, hdr.ex.a_syms))
371		return;
372	    p += hdr.ex.a_syms;
373	    if (xfsread(ino, p, sizeof(int)))
374		return;
375	    x = *(uint32_t *)p;
376	    p += sizeof(int);
377	    x -= sizeof(int);
378	    if (xfsread(ino, p, x))
379		return;
380	    p += x;
381	}
382    } else {
383	fs_off = hdr.eh.e_phoff;
384	for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
385	    if (xfsread(ino, ep + j, sizeof(ep[0])))
386		return;
387	    if (ep[j].p_type == PT_LOAD)
388		j++;
389	}
390	for (i = 0; i < 2; i++) {
391	    p = PTOV(ep[i].p_paddr & 0xffffff);
392	    fs_off = ep[i].p_offset;
393	    if (xfsread(ino, p, ep[i].p_filesz))
394		return;
395	}
396	p += roundup2(ep[1].p_memsz, PAGE_SIZE);
397	bootinfo.bi_symtab = VTOP(p);
398	if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
399	    fs_off = hdr.eh.e_shoff + sizeof(es[0]) *
400		(hdr.eh.e_shstrndx + 1);
401	    if (xfsread(ino, &es, sizeof(es)))
402		return;
403	    for (i = 0; i < 2; i++) {
404		memcpy(p, &es[i].sh_size, sizeof(es[i].sh_size));
405		p += sizeof(es[i].sh_size);
406		fs_off = es[i].sh_offset;
407		if (xfsread(ino, p, es[i].sh_size))
408		    return;
409		p += es[i].sh_size;
410	    }
411	}
412	addr = hdr.eh.e_entry & 0xffffff;
413    }
414    bootinfo.bi_esymtab = VTOP(p);
415    bootinfo.bi_kernelname = VTOP(fname);
416    bootinfo.bi_bios_dev = dsk.drive;
417    __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
418	   MAKEBOOTDEV(dev_maj[dsk.type], 0, dsk.slice, dsk.unit, dsk.part),
419	   0, 0, 0, VTOP(&bootinfo));
420}
421
422static int
423parse(char *arg)
424{
425    char *p, *q;
426    int drv, c, i;
427
428    while ((c = *arg++)) {
429	if (c == ' ' || c == '\t' || c == '\n')
430	    continue;
431	for (p = arg; *p && *p != '\n' && *p != ' ' && *p != '\t'; p++);
432	if (*p)
433	    *p++ = 0;
434	if (c == '-') {
435	    while ((c = *arg++)) {
436		for (i = 0; c != optstr[i]; i++)
437		    if (i == NOPT - 1)
438			return -1;
439		opts ^= 1 << flags[i];
440	    }
441	    if (opts & 1 << RBX_PROBEKBD) {
442		i = *(uint8_t *)PTOV(0x496) & 0x10;
443		printf("Keyboard: %s\n", i ? "yes" : "no");
444		if (!i)
445		    opts |= 1 << RBX_DUAL | 1 << RBX_SERIAL;
446		opts &= ~(1 << RBX_PROBEKBD);
447	    }
448	    ioctrl = opts & 1 << RBX_DUAL ? 0x3 :
449		     opts & 1 << RBX_SERIAL ? 0x2 : 0x1;
450	    if (ioctrl & 0x2)
451	        sio_init();
452	} else {
453	    for (q = arg--; *q && *q != '('; q++);
454	    if (*q) {
455		drv = -1;
456		if (arg[1] == ':') {
457		    if (*arg < '0' || *arg > '9')
458			return -1;
459		    drv = *arg - '0';
460		    arg += 2;
461		}
462		if (q - arg != 2)
463		    return -1;
464		for (i = 0; arg[0] != dev_nm[i][0] ||
465			    arg[1] != dev_nm[i][1]; i++)
466		    if (i == NDEV - 1)
467			return -1;
468		dsk.type = i;
469		arg += 3;
470		if (arg[1] != ',' || *arg < '0' || *arg > '9')
471		    return -1;
472		dsk.unit = *arg - '0';
473		arg += 2;
474		dsk.slice = WHOLE_DISK_SLICE;
475		if (arg[1] == ',') {
476		    if (*arg < '0' || *arg > '0' + NDOSPART)
477			return -1;
478		    if ((dsk.slice = *arg - '0'))
479			dsk.slice++;
480		    arg += 2;
481		}
482		if (arg[1] != ')' || *arg < 'a' || *arg > 'p')
483		    return -1;
484		dsk.part = *arg - 'a';
485		arg += 2;
486		if (drv == -1)
487		    drv = dsk.unit;
488		dsk.drive = (dsk.type == TYPE_WD ||
489			     dsk.type == TYPE_AD ||
490			     dsk.type == TYPE_DA ? DRV_HARD : 0) + drv;
491		dsk.meta = 0;
492		fsread(0, NULL, 0);
493	    }
494	    if ((i = p - arg - !*(p - 1))) {
495		if (i >= sizeof(kname))
496		    return -1;
497		memcpy(kname, arg, i + 1);
498	    }
499	}
500	arg = p;
501    }
502    return 0;
503}
504
505static ino_t
506lookup(const char *path)
507{
508    char name[MAXNAMLEN + 1];
509    const char *s;
510    ino_t ino;
511    ssize_t n;
512    int dt;
513
514    ino = ROOTINO;
515    dt = DT_DIR;
516    for (;;) {
517	if (*path == '/')
518	    path++;
519	if (!*path)
520	    break;
521	for (s = path; *s && *s != '/'; s++);
522	if ((n = s - path) > MAXNAMLEN)
523	    return 0;
524	ls = *path == '?' && n == 1 && !*s;
525	memcpy(name, path, n);
526	name[n] = 0;
527	if ((dt = fsfind(name, &ino)) <= 0)
528	    break;
529	path = s;
530    }
531    return dt == DT_REG ? ino : 0;
532}
533static int
534xfsread(ino_t inode, void *buf, size_t nbyte)
535{
536    if (fsread(inode, buf, nbyte) != nbyte) {
537	printf("Invalid %s\n", "format");
538	return -1;
539    }
540    return 0;
541}
542
543static ssize_t
544fsread(ino_t inode, void *buf, size_t nbyte)
545{
546    static struct dinode din;
547    static ino_t inomap;
548    static daddr_t blkmap, indmap;
549    char *blkbuf;
550    ufs_daddr_t *indbuf;
551    struct fs *fs;
552    char *s;
553    ufs_daddr_t lbn, addr;
554    daddr_t vbaddr;
555    size_t n, nb, off, vboff;
556
557    blkbuf = dmadat->blkbuf;
558    indbuf = dmadat->indbuf;
559    fs = (struct fs *)dmadat->sbbuf;
560    if (!dsk.meta) {
561	inomap = 0;
562	if (dskread(fs, SBOFF / DEV_BSIZE, SBSIZE / DEV_BSIZE))
563	    return -1;
564	if (fs->fs_magic != FS_MAGIC) {
565	    printf("Not ufs\n");
566	    return -1;
567	}
568	dsk.meta++;
569    }
570    if (!inode)
571	return 0;
572    if (inomap != inode) {
573	if (dskread(blkbuf, INO_TO_VBA(fs, inode), DBPERVBLK))
574	    return -1;
575	din = ((struct dinode *)blkbuf)[INO_TO_VBO(fs, inode)];
576	inomap = inode;
577	fs_off = 0;
578	blkmap = indmap = 0;
579    }
580    s = buf;
581    if (nbyte > (n = din.di_size - fs_off))
582	nbyte = n;
583    nb = nbyte;
584    while (nb) {
585	lbn = lblkno(fs, fs_off);
586	off = blkoff(fs, fs_off);
587	if (lbn < NDADDR)
588	    addr = din.di_db[lbn];
589	else {
590	    vbaddr = FS_TO_VBA(fs, din.di_ib[0], sizeof(indbuf[0]) *
591		((lbn - NDADDR) % NINDIR(fs)));
592	    if (indmap != vbaddr) {
593		if (dskread(indbuf, vbaddr, DBPERVBLK))
594		    return -1;
595		indmap = vbaddr;
596	    }
597	    addr = indbuf[(lbn - NDADDR) % INDIRPERVBLK];
598	}
599	vbaddr = FS_TO_VBA(fs, addr, off);
600	vboff = FS_TO_VBO(fs, addr, off);
601	n = dblksize(fs, &din, lbn) - (off & ~VBLKMASK);
602	if (n > VBLKSIZE)
603		n = VBLKSIZE;
604	if (blkmap != vbaddr) {
605	    if (dskread(blkbuf, vbaddr, n >> DEV_BSHIFT))
606		return -1;
607	    blkmap = vbaddr;
608	}
609	n -= vboff;
610	if (n > nb)
611	    n = nb;
612	memcpy(s, blkbuf + vboff, n);
613	s += n;
614	fs_off += n;
615	nb -= n;
616    }
617    return nbyte;
618}
619
620static int
621dskread(void *buf, unsigned lba, unsigned nblk)
622{
623    struct dos_partition *dp;
624    struct disklabel *d;
625    char *sec;
626    unsigned sl, i;
627
628    if (!dsk.meta) {
629	sec = dmadat->secbuf;
630	dsk.start = 0;
631	if (drvread(sec, DOSBBSECTOR, 1))
632	    return -1;
633	dp = (void *)(sec + DOSPARTOFF);
634	sl = dsk.slice;
635	if (sl < BASE_SLICE) {
636	    for (i = 0; i < NDOSPART; i++)
637		if (dp[i].dp_typ == DOSPTYP_386BSD &&
638		    (dp[i].dp_flag & 0x80 || sl < BASE_SLICE)) {
639		    sl = BASE_SLICE + i;
640		    if (dp[i].dp_flag & 0x80 ||
641			dsk.slice == COMPATIBILITY_SLICE)
642			break;
643		}
644	    if (dsk.slice == WHOLE_DISK_SLICE)
645		dsk.slice = sl;
646	}
647	if (sl != WHOLE_DISK_SLICE) {
648	    if (sl != COMPATIBILITY_SLICE)
649		dp += sl - BASE_SLICE;
650	    if (dp->dp_typ != DOSPTYP_386BSD) {
651		printf("Invalid %s\n", "slice");
652		return -1;
653	    }
654	    dsk.start = dp->dp_start;
655	}
656	if (drvread(sec, dsk.start + LABELSECTOR, 1))
657		return -1;
658	d = (void *)(sec + LABELOFFSET);
659	if (d->d_magic != DISKMAGIC || d->d_magic2 != DISKMAGIC) {
660	    if (dsk.part != RAW_PART) {
661		printf("Invalid %s\n", "label");
662		return -1;
663	    }
664	} else {
665	    if (!dsk.init) {
666		if (d->d_type == DTYPE_SCSI)
667		    dsk.type = TYPE_DA;
668		dsk.init++;
669	    }
670	    if (dsk.part >= d->d_npartitions ||
671		!d->d_partitions[dsk.part].p_size) {
672		printf("Invalid %s\n", "partition");
673		return -1;
674	    }
675	    dsk.start = d->d_partitions[dsk.part].p_offset;
676	}
677    }
678    return drvread(buf, dsk.start + lba, nblk);
679}
680
681static int
682printf(const char *fmt,...)
683{
684    static const char digits[16] = "0123456789abcdef";
685    va_list ap;
686    char buf[10];
687    char *s;
688    unsigned r, u;
689    int c;
690
691    va_start(ap, fmt);
692    while ((c = *fmt++)) {
693	if (c == '%') {
694	    c = *fmt++;
695	    switch (c) {
696	    case 'c':
697		putchar(va_arg(ap, int));
698		continue;
699	    case 's':
700		for (s = va_arg(ap, char *); *s; s++)
701		    putchar(*s);
702		continue;
703	    case 'u':
704	    case 'x':
705		r = c == 'u' ? 10U : 16U;
706		u = va_arg(ap, unsigned);
707		s = buf;
708		do
709		    *s++ = digits[u % r];
710		while (u /= r);
711		while (--s >= buf)
712		    putchar(*s);
713		continue;
714	    }
715	}
716	putchar(c);
717    }
718    va_end(ap);
719    return 0;
720}
721
722static int
723putchar(int c)
724{
725    if (c == '\n')
726	xputc('\r');
727    return xputc(c);
728}
729
730static void *
731memcpy(void *dst, const void *src, size_t size)
732{
733    const char *s;
734    char *d;
735
736    for (d = dst, s = src; size; size--)
737	*d++ = *s++;
738    return dst;
739}
740
741static uint32_t
742memsize(int type)
743{
744    v86.addr = type;
745    v86.eax = 0x8800;
746    v86int();
747    return v86.eax;
748}
749
750static int
751drvread(void *buf, unsigned lba, unsigned nblk)
752{
753    static unsigned c = 0x2d5c7c2f;
754
755    printf("%c\b", c = c << 8 | c >> 24);
756    v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
757    v86.addr = XREADORG;		/* call to xread in boot1 */
758    v86.es = VTOPSEG(buf);
759    v86.eax = lba;
760    v86.ebx = VTOPOFF(buf);
761    v86.ecx = lba >> 16;
762    v86.edx = nblk << 8 | dsk.drive;
763    v86int();
764    v86.ctl = V86_FLAGS;
765    if (V86_CY(v86.efl)) {
766	printf("Disk error 0x%x (lba=0x%x)\n", v86.eax >> 8 & 0xff,
767	       lba);
768	return -1;
769    }
770    return 0;
771}
772
773static int
774keyhit(unsigned ticks)
775{
776    uint32_t t0, t1;
777
778    t0 = 0;
779    for (;;) {
780	if (xgetc(1))
781	    return 1;
782	t1 = *(uint32_t *)PTOV(0x46c);
783	if (!t0)
784	    t0 = t1;
785	if (t1 < t0 || t1 >= t0 + ticks)
786	    return 0;
787    }
788}
789
790static int
791xputc(int c)
792{
793    if (ioctrl & 0x1)
794	putc(c);
795    if (ioctrl & 0x2)
796	sio_putc(c);
797    return c;
798}
799
800static int
801xgetc(int fn)
802{
803    for (;;) {
804	if (ioctrl & 0x1 && getc(1))
805	    return fn ? 1 : getc(0);
806	if (ioctrl & 0x2 && sio_ischar())
807	    return fn ? 1 : sio_getc();
808	if (fn)
809	    return 0;
810    }
811}
812
813static int
814getc(int fn)
815{
816    v86.addr = 0x16;
817    v86.eax = fn << 8;
818    v86int();
819    return fn == 0 ? v86.eax & 0xff : !V86_ZR(v86.efl);
820}
821