gptboot.c revision 57090
1258945Sroberto/*
2258945Sroberto * Copyright (c) 1998 Robert Nordier
3258945Sroberto * All rights reserved.
4258945Sroberto *
5258945Sroberto * Redistribution and use in source and binary forms are freely
6258945Sroberto * permitted provided that the above copyright notice and this
7258945Sroberto * paragraph and the following disclaimer are duplicated in all
8258945Sroberto * such forms.
9258945Sroberto *
10258945Sroberto * This software is provided "AS IS" and without any express or
11258945Sroberto * implied warranties, including, without limitation, the implied
12258945Sroberto * warranties of merchantability and fitness for a particular
13258945Sroberto * purpose.
14258945Sroberto */
15258945Sroberto
16258945Sroberto/*
17258945Sroberto * $FreeBSD: head/sys/boot/i386/gptboot/gptboot.c 57090 2000-02-09 19:23:46Z ru $
18258945Sroberto */
19258945Sroberto
20258945Sroberto#include <sys/param.h>
21258945Sroberto#include <sys/reboot.h>
22258945Sroberto#include <sys/diskslice.h>
23258945Sroberto#include <sys/disklabel.h>
24258945Sroberto#include <sys/dirent.h>
25258945Sroberto#include <machine/bootinfo.h>
26258945Sroberto
27258945Sroberto#include <ufs/ffs/fs.h>
28258945Sroberto#include <ufs/ufs/dinode.h>
29258945Sroberto
30258945Sroberto#include <stdarg.h>
31258945Sroberto
32258945Sroberto#include <a.out.h>
33258945Sroberto#include <elf.h>
34258945Sroberto
35258945Sroberto#include <btxv86.h>
36258945Sroberto
37258945Sroberto#include "lib.h"
38258945Sroberto
39258945Sroberto#define RBX_ASKNAME	0x0	/* -a */
40258945Sroberto#define RBX_SINGLE	0x1	/* -s */
41258945Sroberto#define RBX_DFLTROOT	0x5	/* -r */
42258945Sroberto#define RBX_KDB 	0x6	/* -d */
43258945Sroberto#define RBX_CONFIG	0xa	/* -c */
44258945Sroberto#define RBX_VERBOSE	0xb	/* -v */
45258945Sroberto#define RBX_SERIAL	0xc	/* -h */
46258945Sroberto#define RBX_CDROM	0xd	/* -C */
47258945Sroberto#define RBX_GDB 	0xf	/* -g */
48258945Sroberto#define RBX_DUAL	0x1d	/* -D */
49258945Sroberto#define RBX_PROBEKBD	0x1e	/* -P */
50258945Sroberto
51258945Sroberto#define RBX_MASK	0xffff
52258945Sroberto
53258945Sroberto#define PATH_CONFIG	"/boot.config"
54258945Sroberto#define PATH_BOOT3	"/boot/loader"
55258945Sroberto#define PATH_KERNEL	"/kernel"
56258945Sroberto
57258945Sroberto#define ARGS		0x900
58258945Sroberto#define NOPT		11
59258945Sroberto#define BSIZEMAX	8192
60258945Sroberto#define NDEV		5
61#define MEM_BASE	0x12
62#define MEM_EXT 	0x15
63#define V86_CY(x)	((x) & 1)
64#define V86_ZR(x)	((x) & 0x40)
65
66#define DRV_HARD	0x80
67#define DRV_MASK	0x7f
68
69#define TYPE_AD		0
70#define TYPE_WD		1
71#define TYPE_WFD 	2
72#define TYPE_FD		3
73#define TYPE_DA		4
74
75extern uint32_t _end;
76
77static const char optstr[NOPT] = "DhaCcdgPrsv";
78static const unsigned char flags[NOPT] = {
79    RBX_DUAL,
80    RBX_SERIAL,
81    RBX_ASKNAME,
82    RBX_CDROM,
83    RBX_CONFIG,
84    RBX_KDB,
85    RBX_GDB,
86    RBX_PROBEKBD,
87    RBX_DFLTROOT,
88    RBX_SINGLE,
89    RBX_VERBOSE
90};
91
92static const char *const dev_nm[] = {"ad", "wd", "  ", "fd", "da"};
93static const unsigned dev_maj[] = {30, 0, 1, 2, 4};
94
95static struct dsk {
96    unsigned drive;
97    unsigned type;
98    unsigned unit;
99    unsigned slice;
100    unsigned part;
101    unsigned start;
102    int init;
103    int meta;
104} dsk;
105static char cmd[512];
106static char kname[1024];
107static uint32_t opts;
108static struct bootinfo bootinfo;
109static int ls;
110static uint32_t fs_off;
111static uint8_t ioctrl = 0x1;
112
113void exit(int);
114static void load(const char *);
115static int parse(char *);
116static void readfile(const char *, void *, size_t);
117static ino_t lookup(const char *);
118static int fsfind(const char *, ino_t *);
119static int xfsread(ino_t, void *, size_t);
120static ssize_t fsread(ino_t, void *, size_t);
121static int dskread(void *, unsigned, unsigned);
122static int printf(const char *,...);
123static void getstr(char *, int);
124static int putchar(int);
125static int getchar(void);
126static void *memcpy(void *, const void *, size_t);
127static int strcmp(const char *, const char *);
128static void *malloc(size_t);
129static uint32_t memsize(int);
130static uint32_t drvinfo(int);
131static int drvread(void *, unsigned, unsigned);
132static int keyhit(unsigned);
133static int xputc(int);
134static int xgetc(int);
135static void putc(int);
136static int getc(int);
137
138int
139main(void)
140{
141    int autoboot, i;
142
143    v86.ctl = V86_FLAGS;
144    dsk.drive = *(uint8_t *)PTOV(ARGS);
145    dsk.type = dsk.drive & DRV_HARD ? TYPE_AD : TYPE_FD;
146    dsk.unit = dsk.drive & DRV_MASK;
147    dsk.slice = *(uint8_t *)PTOV(ARGS + 1) + 1;
148    bootinfo.bi_version = BOOTINFO_VERSION;
149    bootinfo.bi_size = sizeof(bootinfo);
150    bootinfo.bi_basemem = memsize(MEM_BASE);
151    bootinfo.bi_extmem = memsize(MEM_EXT);
152    bootinfo.bi_memsizes_valid++;
153    for (i = 0; i < N_BIOS_GEOM; i++)
154	bootinfo.bi_bios_geom[i] = drvinfo(i);
155    autoboot = 2;
156    readfile(PATH_CONFIG, cmd, sizeof(cmd));
157    if (*cmd) {
158	printf("%s: %s", PATH_CONFIG, cmd);
159	if (parse(cmd))
160	    autoboot = 0;
161	*cmd = 0;
162    }
163    if (autoboot && !*kname) {
164	if (autoboot == 2) {
165	    memcpy(kname, PATH_BOOT3, sizeof(PATH_BOOT3));
166	    if (!keyhit(0x37)) {
167		load(kname);
168		autoboot = 1;
169	    }
170	}
171	if (autoboot == 1)
172	    memcpy(kname, PATH_KERNEL, sizeof(PATH_KERNEL));
173    }
174    for (;;) {
175	printf(" \n>> FreeBSD/i386 BOOT\n"
176	       "Default: %u:%s(%u,%c)%s\n"
177	       "boot: ",
178	       dsk.drive & DRV_MASK, dev_nm[dsk.type], dsk.unit,
179	       'a' + dsk.part, kname);
180	if (ioctrl & 0x2)
181	    sio_flush();
182	if (!autoboot || keyhit(0x5a))
183	    getstr(cmd, sizeof(cmd));
184	else
185	    putchar('\n');
186	autoboot = 0;
187	if (parse(cmd))
188	    putchar('\a');
189	else
190	    load(kname);
191    }
192}
193
194void
195exit(int x)
196{
197}
198
199static void
200load(const char *fname)
201{
202    union {
203	struct exec ex;
204	Elf32_Ehdr eh;
205    } hdr;
206    Elf32_Phdr ep[2];
207    Elf32_Shdr es[2];
208    caddr_t p;
209    ino_t ino;
210    uint32_t addr, x;
211    int fmt, i, j;
212
213    if (!(ino = lookup(fname))) {
214	if (!ls)
215	    printf("No %s\n", fname);
216	return;
217    }
218    if (xfsread(ino, &hdr, sizeof(hdr)))
219	return;
220    if (N_GETMAGIC(hdr.ex) == ZMAGIC)
221	fmt = 0;
222    else if (IS_ELF(hdr.eh))
223	fmt = 1;
224    else {
225	printf("Invalid %s\n", "format");
226	return;
227    }
228    if (fmt == 0) {
229	addr = hdr.ex.a_entry & 0xffffff;
230	p = PTOV(addr);
231	fs_off = PAGE_SIZE;
232	if (xfsread(ino, p, hdr.ex.a_text))
233	    return;
234	p += roundup2(hdr.ex.a_text, PAGE_SIZE);
235	if (xfsread(ino, p, hdr.ex.a_data))
236	    return;
237	p += hdr.ex.a_data + roundup2(hdr.ex.a_bss, PAGE_SIZE);
238	bootinfo.bi_symtab = VTOP(p);
239	memcpy(p, &hdr.ex.a_syms, sizeof(hdr.ex.a_syms));
240	p += sizeof(hdr.ex.a_syms);
241	if (hdr.ex.a_syms) {
242	    if (xfsread(ino, p, hdr.ex.a_syms))
243		return;
244	    p += hdr.ex.a_syms;
245	    if (xfsread(ino, p, sizeof(int)))
246		return;
247	    x = *(uint32_t *)p;
248	    p += sizeof(int);
249	    x -= sizeof(int);
250	    if (xfsread(ino, p, x))
251		return;
252	    p += x;
253	}
254    } else {
255	fs_off = hdr.eh.e_phoff;
256	for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
257	    if (xfsread(ino, ep + j, sizeof(ep[0])))
258		return;
259	    if (ep[j].p_type == PT_LOAD)
260		j++;
261	}
262	for (i = 0; i < 2; i++) {
263	    p = PTOV(ep[i].p_paddr & 0xffffff);
264	    fs_off = ep[i].p_offset;
265	    if (xfsread(ino, p, ep[i].p_filesz))
266		return;
267	}
268	p += roundup2(ep[1].p_memsz, PAGE_SIZE);
269	bootinfo.bi_symtab = VTOP(p);
270	if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
271	    fs_off = hdr.eh.e_shoff + sizeof(es[0]) *
272		(hdr.eh.e_shstrndx + 1);
273	    if (xfsread(ino, &es, sizeof(es)))
274		return;
275	    for (i = 0; i < 2; i++) {
276		memcpy(p, &es[i].sh_size, sizeof(es[i].sh_size));
277		p += sizeof(es[i].sh_size);
278		fs_off = es[i].sh_offset;
279		if (xfsread(ino, p, es[i].sh_size))
280		    return;
281		p += es[i].sh_size;
282	    }
283	}
284	addr = hdr.eh.e_entry & 0xffffff;
285    }
286    bootinfo.bi_esymtab = VTOP(p);
287    bootinfo.bi_kernelname = VTOP(fname);
288    bootinfo.bi_bios_dev = dsk.drive;
289    __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
290	   MAKEBOOTDEV(dev_maj[dsk.type], 0, dsk.slice, dsk.unit, dsk.part),
291	   0, 0, 0, VTOP(&bootinfo));
292}
293
294static int
295parse(char *arg)
296{
297    char *p, *q;
298    int drv, c, i;
299
300    while ((c = *arg++)) {
301	if (c == ' ')
302	    continue;
303	for (p = arg; *p && *p != '\n' && *p != ' '; p++);
304	if (*p)
305	    *p++ = 0;
306	if (c == '-') {
307	    while ((c = *arg++)) {
308		for (i = 0; c != optstr[i]; i++)
309		    if (i == NOPT - 1)
310			return -1;
311		opts ^= 1 << flags[i];
312	    }
313	    if (opts & 1 << RBX_PROBEKBD) {
314		i = *(uint8_t *)PTOV(0x496) & 0x10;
315		printf("Keyboard: %s\n", i ? "yes" : "no");
316		if (!i)
317		    opts |= 1 << RBX_DUAL | 1 << RBX_SERIAL;
318		opts &= ~(1 << RBX_PROBEKBD);
319	    }
320	    ioctrl = opts & 1 << RBX_DUAL ? 0x3 :
321		     opts & 1 << RBX_SERIAL ? 0x2 : 0x1;
322	    if (ioctrl & 0x2)
323	        sio_init();
324	} else {
325	    for (q = arg--; *q && *q != '('; q++);
326	    if (*q) {
327		drv = -1;
328		if (arg[1] == ':') {
329		    if (*arg < '0' || *arg > '9')
330			return -1;
331		    drv = *arg - '0';
332		    arg += 2;
333		}
334		if (q - arg != 2)
335		    return -1;
336		for (i = 0; arg[0] != dev_nm[i][0] ||
337			    arg[1] != dev_nm[i][1]; i++)
338		    if (i == NDEV - 1)
339			return -1;
340		dsk.type = i;
341		arg += 3;
342		if (arg[1] != ',' || *arg < '0' || *arg > '9')
343		    return -1;
344		dsk.unit = *arg - '0';
345		arg += 2;
346		dsk.slice = WHOLE_DISK_SLICE;
347		if (arg[1] == ',') {
348		    if (*arg < '0' || *arg > '0' + NDOSPART)
349			return -1;
350		    if ((dsk.slice = *arg - '0'))
351			dsk.slice++;
352		    arg += 2;
353		}
354		if (arg[1] != ')' || *arg < 'a' || *arg > 'p')
355		    return -1;
356		dsk.part = *arg - 'a';
357		arg += 2;
358		if (drv == -1)
359		    drv = dsk.unit;
360		dsk.drive = (dsk.type == TYPE_WD ||
361			     dsk.type == TYPE_AD ||
362			     dsk.type == TYPE_DA ? DRV_HARD : 0) + drv;
363		dsk.meta = 0;
364		fsread(0, NULL, 0);
365	    }
366	    if ((i = p - arg - !*(p - 1))) {
367		if (i >= sizeof(kname))
368		    return -1;
369		memcpy(kname, arg, i + 1);
370	    }
371	}
372	arg = p;
373    }
374    return 0;
375}
376
377static void
378readfile(const char *fname, void *buf, size_t size)
379{
380    ino_t ino;
381
382    if ((ino = lookup(fname)))
383	fsread(ino, buf, size);
384}
385
386static ino_t
387lookup(const char *path)
388{
389    char name[MAXNAMLEN + 1];
390    const char *s;
391    ino_t ino;
392    ssize_t n;
393    int dt;
394
395    ino = ROOTINO;
396    dt = DT_DIR;
397    for (;;) {
398	if (*path == '/')
399	    path++;
400	if (!*path)
401	    break;
402	for (s = path; *s && *s != '/'; s++);
403	if ((n = s - path) > MAXNAMLEN)
404	    return 0;
405	ls = *path == '?' && n == 1 && !*s;
406	memcpy(name, path, n);
407	name[n] = 0;
408	if ((dt = fsfind(name, &ino)) <= 0)
409	    break;
410	path = s;
411    }
412    return dt == DT_REG ? ino : 0;
413}
414
415static int
416fsfind(const char *name, ino_t * ino)
417{
418    char buf[DEV_BSIZE];
419    struct dirent *d;
420    char *s;
421    ssize_t n;
422
423    fs_off = 0;
424    while ((n = fsread(*ino, buf, DEV_BSIZE)) > 0)
425	for (s = buf; s < buf + DEV_BSIZE;) {
426	    d = (void *)s;
427	    if (ls)
428		printf("%s ", d->d_name);
429	    else if (!strcmp(name, d->d_name)) {
430		*ino = d->d_fileno;
431		return d->d_type;
432	    }
433	    s += d->d_reclen;
434	}
435    if (n != -1 && ls)
436	putchar('\n');
437    return 0;
438}
439
440static int
441xfsread(ino_t inode, void *buf, size_t nbyte)
442{
443    if (fsread(inode, buf, nbyte) != nbyte) {
444	printf("Invalid %s\n", "format");
445	return -1;
446    }
447    return 0;
448}
449
450static ssize_t
451fsread(ino_t inode, void *buf, size_t nbyte)
452{
453    static struct fs fs;
454    static struct dinode din;
455    static char *blkbuf;
456    static ufs_daddr_t *indbuf;
457    static ino_t inomap;
458    static ufs_daddr_t blkmap, indmap;
459    static unsigned fsblks;
460    char *s;
461    ufs_daddr_t lbn, addr;
462    size_t n, nb, off;
463
464    if (!dsk.meta) {
465	if (!blkbuf)
466	    blkbuf = malloc(BSIZEMAX);
467	inomap = 0;
468	if (dskread(blkbuf, SBOFF / DEV_BSIZE, SBSIZE / DEV_BSIZE))
469	    return -1;
470	memcpy(&fs, blkbuf, sizeof(fs));
471	if (fs.fs_magic != FS_MAGIC) {
472	    printf("Not ufs\n");
473	    return -1;
474	}
475	fsblks = fs.fs_bsize >> DEV_BSHIFT;
476	dsk.meta++;
477    }
478    if (!inode)
479	return 0;
480    if (inomap != inode) {
481	if (dskread(blkbuf, fsbtodb(&fs, ino_to_fsba(&fs, inode)),
482		    fsblks))
483	    return -1;
484	din = ((struct dinode *)blkbuf)[inode % INOPB(&fs)];
485	inomap = inode;
486	fs_off = 0;
487	blkmap = indmap = 0;
488    }
489    s = buf;
490    if (nbyte > (n = din.di_size - fs_off))
491	nbyte = n;
492    nb = nbyte;
493    while (nb) {
494	lbn = lblkno(&fs, fs_off);
495	if (lbn < NDADDR)
496	    addr = din.di_db[lbn];
497	else {
498	    if (indmap != din.di_ib[0]) {
499		if (!indbuf)
500		    indbuf = malloc(BSIZEMAX);
501		if (dskread(indbuf, fsbtodb(&fs, din.di_ib[0]),
502			    fsblks))
503		    return -1;
504		indmap = din.di_ib[0];
505	    }
506	    addr = indbuf[(lbn - NDADDR) % NINDIR(&fs)];
507	}
508	n = dblksize(&fs, &din, lbn);
509	if (blkmap != addr) {
510	    if (dskread(blkbuf, fsbtodb(&fs, addr), n >> DEV_BSHIFT))
511		return -1;
512	    blkmap = addr;
513	}
514	off = blkoff(&fs, fs_off);
515	n -= off;
516	if (n > nb)
517	    n = nb;
518	memcpy(s, blkbuf + off, n);
519	s += n;
520	fs_off += n;
521	nb -= n;
522    }
523    return nbyte;
524}
525
526static int
527dskread(void *buf, unsigned lba, unsigned nblk)
528{
529    static char *sec;
530    struct dos_partition *dp;
531    struct disklabel *d;
532    unsigned sl, i;
533
534    if (!dsk.meta) {
535	if (!sec)
536	    sec = malloc(DEV_BSIZE);
537	dsk.start = 0;
538	if (drvread(sec, DOSBBSECTOR, 1))
539	    return -1;
540	dp = (void *)(sec + DOSPARTOFF);
541	sl = dsk.slice;
542	if (sl < BASE_SLICE) {
543	    for (i = 0; i < NDOSPART; i++)
544		if (dp[i].dp_typ == DOSPTYP_386BSD &&
545		    (dp[i].dp_flag & 0x80 || sl < BASE_SLICE)) {
546		    sl = BASE_SLICE + i;
547		    if (dp[i].dp_flag & 0x80 ||
548			dsk.slice == COMPATIBILITY_SLICE)
549			break;
550		}
551	    if (dsk.slice == WHOLE_DISK_SLICE)
552		dsk.slice = sl;
553	}
554	if (sl != WHOLE_DISK_SLICE) {
555	    if (sl != COMPATIBILITY_SLICE)
556		dp += sl - BASE_SLICE;
557	    if (dp->dp_typ != DOSPTYP_386BSD) {
558		printf("Invalid %s\n", "slice");
559		return -1;
560	    }
561	    dsk.start = dp->dp_start;
562	}
563	if (drvread(sec, dsk.start + LABELSECTOR, 1))
564		return -1;
565	d = (void *)(sec + LABELOFFSET);
566	if (d->d_magic != DISKMAGIC || d->d_magic2 != DISKMAGIC) {
567	    if (dsk.part != RAW_PART) {
568		printf("Invalid %s\n", "label");
569		return -1;
570	    }
571	} else {
572	    if (!dsk.init) {
573		if (d->d_type == DTYPE_SCSI)
574		    dsk.type = TYPE_DA;
575		dsk.init++;
576	    }
577	    if (dsk.part >= d->d_npartitions ||
578		!d->d_partitions[dsk.part].p_size) {
579		printf("Invalid %s\n", "partition");
580		return -1;
581	    }
582	    dsk.start = d->d_partitions[dsk.part].p_offset;
583	}
584    }
585    return drvread(buf, dsk.start + lba, nblk);
586}
587
588static int
589printf(const char *fmt,...)
590{
591    static const char digits[16] = "0123456789abcdef";
592    va_list ap;
593    char buf[10];
594    char *s;
595    unsigned r, u;
596    int c;
597
598    va_start(ap, fmt);
599    while ((c = *fmt++)) {
600	if (c == '%') {
601	    c = *fmt++;
602	    switch (c) {
603	    case 'c':
604		putchar(va_arg(ap, int));
605		continue;
606	    case 's':
607		for (s = va_arg(ap, char *); *s; s++)
608		    putchar(*s);
609		continue;
610	    case 'u':
611	    case 'x':
612		r = c == 'u' ? 10U : 16U;
613		u = va_arg(ap, unsigned);
614		s = buf;
615		do
616		    *s++ = digits[u % r];
617		while (u /= r);
618		while (--s >= buf)
619		    putchar(*s);
620		continue;
621	    }
622	}
623	putchar(c);
624    }
625    va_end(ap);
626    return 0;
627}
628
629static void
630getstr(char *str, int size)
631{
632    char *s;
633    int c;
634
635    s = str;
636    do {
637	switch (c = getchar()) {
638	case 0:
639	    break;
640	case '\b':
641	case '\177':
642	    if (s > str) {
643		s--;
644		putchar('\b');
645		putchar(' ');
646	    } else
647		c = 0;
648	    break;
649	case '\n':
650	    *s = 0;
651	    break;
652	default:
653	    if (s - str < size - 1)
654		*s++ = c;
655	}
656	if (c)
657	    putchar(c);
658    } while (c != '\n');
659}
660
661static int
662putchar(int c)
663{
664    if (c == '\n')
665	xputc('\r');
666    return xputc(c);
667}
668
669static int
670getchar(void)
671{
672    int c;
673
674    c = xgetc(0);
675    if (c == '\r')
676	c = '\n';
677    return c;
678}
679
680static void *
681memcpy(void *dst, const void *src, size_t size)
682{
683    const char *s;
684    char *d;
685
686    for (d = dst, s = src; size; size--)
687	*d++ = *s++;
688    return dst;
689}
690
691static int
692strcmp(const char *s1, const char *s2)
693{
694    for (; *s1 == *s2 && *s1; s1++, s2++);
695    return (u_char)*s1 - (u_char)*s2;
696}
697
698static void *
699malloc(size_t size)
700{
701    static uint32_t next;
702    void *p;
703
704    if (!next)
705	next = roundup2(__base + _end, 0x10000) - __base;
706    p = (void *)next;
707    next += size;
708    return p;
709}
710
711static uint32_t
712memsize(int type)
713{
714    v86.addr = type;
715    v86.eax = 0x8800;
716    v86int();
717    return v86.eax;
718}
719
720static uint32_t
721drvinfo(int drive)
722{
723    v86.addr = 0x13;
724    v86.eax = 0x800;
725    v86.edx = DRV_HARD + drive;
726    v86int();
727    if (V86_CY(v86.efl))
728	return 0x4f010f;
729    return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
730	   (v86.edx & 0xff00) | (v86.ecx & 0x3f);
731}
732
733static int
734drvread(void *buf, unsigned lba, unsigned nblk)
735{
736    static unsigned c = 0x2d5c7c2f;
737
738    printf("%c\b", c = c << 8 | c >> 24);
739    v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
740    v86.addr = 0x704;		/* call to xread in boot1 */
741    v86.es = VTOPSEG(buf);
742    v86.eax = lba;
743    v86.ebx = VTOPOFF(buf);
744    v86.ecx = lba >> 16;
745    v86.edx = nblk << 8 | dsk.drive;
746    v86int();
747    v86.ctl = V86_FLAGS;
748    if (V86_CY(v86.efl)) {
749	printf("Disk error 0x%x (lba=0x%x)\n", v86.eax >> 8 & 0xff,
750	       lba);
751	return -1;
752    }
753    return 0;
754}
755
756static int
757keyhit(unsigned ticks)
758{
759    uint32_t t0, t1;
760
761    t0 = 0;
762    for (;;) {
763	if (xgetc(1))
764	    return 1;
765	t1 = *(uint32_t *)PTOV(0x46c);
766	if (!t0)
767	    t0 = t1;
768	if (t1 < t0 || t1 >= t0 + ticks)
769	    return 0;
770    }
771}
772
773static int
774xputc(int c)
775{
776    if (ioctrl & 0x1)
777	putc(c);
778    if (ioctrl & 0x2)
779	sio_putc(c);
780    return c;
781}
782
783static int
784xgetc(int fn)
785{
786    for (;;) {
787	if (ioctrl & 0x1 && getc(1))
788	    return fn ? 1 : getc(0);
789	if (ioctrl & 0x2 && sio_ischar())
790	    return fn ? 1 : sio_getc();
791	if (fn)
792	    return 0;
793    }
794}
795
796static void
797putc(int c)
798{
799    v86.addr = 0x10;
800    v86.eax = 0xe00 | (c & 0xff);
801    v86.ebx = 0x7;
802    v86int();
803}
804
805static int
806getc(int fn)
807{
808    v86.addr = 0x16;
809    v86.eax = fn << 8;
810    v86int();
811    return fn == 0 ? v86.eax & 0xff : !V86_ZR(v86.efl);
812}
813