gptboot.c revision 40472 
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 *	$Id: boot2.c,v 1.8 1998/10/17 09:01:13 rnordier Exp $
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
27#include <ufs/ffs/fs.h>
28#include <ufs/ufs/dinode.h>
29
30#include <stdarg.h>
31
32#include <a.out.h>
33#include <elf.h>
34
35#include <btxv86.h>
36
37#include "lib.h"
38
39#define RBX_ASKNAME	0x0	/* -a */
40#define RBX_SINGLE	0x1	/* -s */
41#define RBX_DFLTROOT	0x5	/* -r */
42#define RBX_KDB 	0x6	/* -d */
43#define RBX_CONFIG	0xa	/* -c */
44#define RBX_VERBOSE	0xb	/* -v */
45#define RBX_SERIAL	0xc	/* -h */
46#define RBX_CDROM	0xd	/* -C */
47#define RBX_GDB 	0xf	/* -g */
48#define RBX_DUAL	0x1d	/* -D */
49#define RBX_PROBEKBD	0x1e	/* -P */
50
51#define RBX_MASK	0xffff
52
53#define PATH_CONFIG	"/boot.config"
54#define PATH_BOOT3	"/boot/loader"
55#define PATH_KERNEL	"/kernel"
56#define PATH_HELP	"boot.help"
57
58#define ARGS		0x800
59#define NOPT		11
60#define XOPT		2
61#define BSIZEMAX	8192
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#define DRV_HARD	0x80
69#define DRV_MASK	0x7f
70
71#define MAJ_WD		0
72#define MAJ_WFD 	1
73#define MAJ_FD		2
74#define MAJ_DA		4
75
76extern uint32_t _end;
77
78static const char optstr[NOPT] = "DhaCcdgPrsv";
79static const unsigned char flags[NOPT] = {
80    RBX_DUAL,
81    RBX_SERIAL,
82    RBX_ASKNAME,
83    RBX_CDROM,
84    RBX_CONFIG,
85    RBX_KDB,
86    RBX_GDB,
87    RBX_PROBEKBD,
88    RBX_DFLTROOT,
89    RBX_SINGLE,
90    RBX_VERBOSE
91};
92
93static const char *const dev_nm[] = {"wd", "  ", "fd", "  ", "da"};
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 char help[2048];
108static uint32_t opts;
109static struct bootinfo bootinfo;
110static int ls;
111static uint32_t fs_off;
112static uint8_t ioctrl = 0x1;
113
114void exit(int);
115static void load(const char *);
116static int parse(char *);
117static void readfile(const char *, void *, size_t);
118static ino_t lookup(const char *);
119static int fsfind(const char *, ino_t *);
120static int xfsread(ino_t, void *, size_t);
121static ssize_t fsread(ino_t, void *, size_t);
122static int dskread(void *, unsigned, unsigned);
123static int printf(const char *,...);
124static void getstr(char *, int);
125static int putchar(int);
126static int getchar(void);
127static void *memcpy(void *, const void *, size_t);
128static int strcmp(const char *, const char *);
129static void *malloc(size_t);
130static uint32_t memsize(int);
131static uint32_t drvinfo(int);
132static int drvread(void *, unsigned, unsigned);
133static int keyhit(unsigned);
134static int xputc(int);
135static int xgetc(int);
136static void putc(int);
137static int getc(int);
138
139int
140main(void)
141{
142    int autoboot, helpon, i;
143
144    v86.ctl = V86_FLAGS;
145    dsk.drive = *(uint8_t *)PTOV(ARGS);
146    dsk.type = dsk.drive & DRV_HARD ? MAJ_WD : MAJ_FD;
147    dsk.unit = dsk.drive & DRV_MASK;
148    dsk.slice = *(uint8_t *)PTOV(ARGS + 1) + 1;
149    bootinfo.bi_version = BOOTINFO_VERSION;
150    bootinfo.bi_size = sizeof(bootinfo);
151    bootinfo.bi_basemem = memsize(MEM_BASE);
152    bootinfo.bi_extmem = memsize(MEM_EXT);
153    bootinfo.bi_memsizes_valid++;
154    for (i = 0; i < N_BIOS_GEOM; i++)
155	bootinfo.bi_bios_geom[i] = drvinfo(i);
156    autoboot = 2;
157    helpon = 1;
158    readfile(PATH_HELP, help, sizeof(help));
159    readfile(PATH_CONFIG, cmd, sizeof(cmd));
160    if (*cmd) {
161	printf("%s: %s", PATH_CONFIG, cmd);
162	if (parse(cmd))
163	    autoboot = 0;
164    }
165    if (autoboot && !*kname) {
166	if (autoboot == 2) {
167	    memcpy(kname, PATH_BOOT3, sizeof(PATH_BOOT3));
168	    if (!keyhit(0x37)) {
169		load(kname);
170		autoboot = 1;
171	    }
172	}
173	if (autoboot == 1)
174	    memcpy(kname, PATH_KERNEL, sizeof(PATH_KERNEL));
175    }
176    for (;;) {
177	printf(" \n>> FreeBSD/i386 BOOT\n"
178	       "Default: %u:%s(%u,%c)%s\n"
179	       "%s"
180	       "boot: ",
181	       dsk.drive & DRV_MASK, dev_nm[dsk.type], dsk.unit,
182	       'a' + dsk.part, kname, helpon ? help : "");
183	if (ioctrl & 0x2)
184	    sio_flush();
185	if (!autoboot || keyhit(0x5a))
186	    getstr(cmd, sizeof(cmd));
187	autoboot = helpon = 0;
188	if (parse(cmd))
189	    helpon = 1;
190	else
191	    load(kname);
192    }
193}
194
195void
196exit(int x)
197{
198}
199
200static void
201load(const char *fname)
202{
203    union {
204	struct exec ex;
205	Elf32_Ehdr eh;
206    } hdr;
207    Elf32_Phdr ep[2];
208    Elf32_Shdr es[2];
209    caddr_t p;
210    ino_t ino;
211    uint32_t addr, x;
212    int fmt, i, j;
213
214    if (!(ino = lookup(fname))) {
215	if (!ls)
216	    printf("No %s\n", fname);
217	return;
218    }
219    if (xfsread(ino, &hdr, sizeof(hdr)))
220	return;
221    if (N_GETMAGIC(hdr.ex) == ZMAGIC)
222	fmt = 0;
223    else if (IS_ELF(hdr.eh))
224	fmt = 1;
225    else {
226	printf("Invalid %s\n", "format");
227	return;
228    }
229    if (fmt == 0) {
230	addr = hdr.ex.a_entry & 0xffffff;
231	p = PTOV(addr);
232	printf("%s=0x%x ", "text", (unsigned)hdr.ex.a_text);
233	fs_off = PAGE_SIZE;
234	if (xfsread(ino, p, hdr.ex.a_text))
235	    return;
236	p += roundup2(hdr.ex.a_text, PAGE_SIZE);
237	printf("%s=0x%x ", "data", (unsigned)hdr.ex.a_data);
238	if (xfsread(ino, p, hdr.ex.a_data))
239	    return;
240	p += hdr.ex.a_data;
241	printf("%s=0x%x ", "bss", (unsigned)hdr.ex.a_bss);
242	p += roundup2(hdr.ex.a_bss, PAGE_SIZE);
243	bootinfo.bi_symtab = VTOP(p);
244	memcpy(p, &hdr.ex.a_syms, sizeof(hdr.ex.a_syms));
245	p += sizeof(hdr.ex.a_syms);
246	printf("symbols=[");
247	printf("+0x%x", (unsigned)hdr.ex.a_syms);
248	if (hdr.ex.a_syms) {
249	    if (xfsread(ino, p, hdr.ex.a_syms))
250		return;
251	    p += hdr.ex.a_syms;
252	    if (xfsread(ino, p, sizeof(int)))
253		return;
254	    x = *(uint32_t *)p;
255	    p += sizeof(int);
256	    x -= sizeof(int);
257	    printf("+0x%x", x);
258	    if (xfsread(ino, p, x))
259		return;
260	    p += x;
261	}
262    } else {
263	fs_off = hdr.eh.e_phoff;
264	for (j = i = 0; i < hdr.eh.e_phoff && j < 2; i++) {
265	    if (xfsread(ino, ep + j, sizeof(ep[0])))
266		return;
267	    if (ep[j].p_type == PT_LOAD)
268		j++;
269	}
270	for (i = 0; i < 2; i++) {
271	    p = PTOV(ep[i].p_paddr & 0xffffff);
272	    printf("%s=0x%x ", !i ? "text" : "data", ep[i].p_filesz);
273	    fs_off = ep[i].p_offset;
274	    if (xfsread(ino, p, ep[i].p_filesz))
275		return;
276	}
277	printf("%s=0x%x ", "bss", ep[1].p_memsz - ep[1].p_filesz);
278	p += roundup2(ep[1].p_memsz, PAGE_SIZE);
279	bootinfo.bi_symtab = VTOP(p);
280	printf("symbols=[");
281	if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
282	    fs_off = hdr.eh.e_shoff + sizeof(es[0]) *
283		(hdr.eh.e_shstrndx + 1);
284	    if (xfsread(ino, &es, sizeof(es)))
285		return;
286	    for (i = 0; i < 2; i++) {
287		memcpy(p, &es[i].sh_size, sizeof(es[i].sh_size));
288		p += sizeof(es[i].sh_size);
289		printf("+0x%x", es[i].sh_size);
290		fs_off = es[i].sh_offset;
291		if (xfsread(ino, p, es[i].sh_size))
292		    return;
293		p += es[i].sh_size;
294	    }
295	}
296	addr = hdr.eh.e_entry & 0xffffff;
297    }
298    bootinfo.bi_esymtab = VTOP(p);
299    printf("]\nentry=0x%x\n", addr);
300    bootinfo.bi_kernelname = VTOP(fname);
301    __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
302	   MAKEBOOTDEV(dsk.type, 0, dsk.slice, dsk.unit, dsk.part),
303	   0, 0, 0, VTOP(&bootinfo));
304}
305
306static int
307parse(char *arg)
308{
309    char *p, *q;
310    int drv, c, i;
311
312    while ((c = *arg++)) {
313	if (c == ' ')
314	    continue;
315	for (p = arg; *p && *p != '\n' && *p != ' '; p++);
316	if (*p)
317	    *p++ = 0;
318	if (c == '-') {
319	    while ((c = *arg++)) {
320		for (i = 0; c != optstr[i]; i++)
321		    if (i == NOPT - 1)
322			return -1;
323		if (i < XOPT)
324		    opts ^= 1 << flags[i];
325		else
326		    opts |= 1 << flags[i];
327	    }
328	    if (opts & 1 << RBX_PROBEKBD) {
329		i = *(uint8_t *)PTOV(0x496) & 0x10;
330		printf("Keyboard: %s\n", i ? "yes" : "no");
331		if (!i)
332		    opts |= 1 << RBX_DUAL | 1 << RBX_SERIAL;
333	    }
334	    ioctrl = opts & 1 << RBX_DUAL ? 0x3 :
335		     opts & 1 << RBX_SERIAL ? 0x2 : 0x1;
336	    if (ioctrl & 0x2)
337	        sio_init();
338	} else {
339	    for (q = arg--; *q && *q != '('; q++);
340	    if (*q) {
341		drv = -1;
342		if (arg[1] == ':') {
343		    if (*arg < '0' || *arg > '9')
344			return -1;
345		    drv = *arg - '0';
346		    arg += 2;
347		}
348		if (q - arg != 2)
349		    return -1;
350		for (i = 0; arg[0] != dev_nm[i][0] ||
351			    arg[1] != dev_nm[i][1]; i++)
352		    if (i == NDEV - 1)
353			return -1;
354		dsk.type = i;
355		arg += 3;
356		if (arg[1] != ',' || *arg < '0' || *arg > '9')
357		    return -1;
358		dsk.unit = *arg - '0';
359		arg += 2;
360		dsk.slice = WHOLE_DISK_SLICE;
361		if (arg[1] == ',') {
362		    if (*arg < '0' || *arg > '0' + NDOSPART)
363			return -1;
364		    if ((dsk.slice = *arg - '0'))
365			dsk.slice++;
366		    arg += 2;
367		}
368		if (arg[1] != ')' || *arg < 'a' || *arg > 'p')
369		    return -1;
370		dsk.part = *arg - 'a';
371		arg += 2;
372		if (drv == -1)
373		    drv = dsk.unit;
374		dsk.drive = (dsk.type == MAJ_WD ||
375			     dsk.type == MAJ_DA ? DRV_HARD : 0) + drv;
376		dsk.meta = 0;
377		fsread(0, NULL, 0);
378	    }
379	    if ((i = p - arg - !*(p - 1))) {
380		if (i >= sizeof(kname))
381		    return -1;
382		memcpy(kname, arg, i + 1);
383	    }
384	}
385	arg = p;
386    }
387    return 0;
388}
389
390static void
391readfile(const char *fname, void *buf, size_t size)
392{
393    ino_t ino;
394
395    if ((ino = lookup(fname)))
396	fsread(ino, buf, size);
397}
398
399static ino_t
400lookup(const char *path)
401{
402    char name[MAXNAMLEN + 1];
403    const char *s;
404    ino_t ino;
405    ssize_t n;
406    int dt;
407
408    ino = ROOTINO;
409    dt = DT_DIR;
410    for (;;) {
411	if (*path == '/')
412	    path++;
413	if (!*path)
414	    break;
415	for (s = path; *s && *s != '/'; s++);
416	if ((n = s - path) > MAXNAMLEN)
417	    return 0;
418	ls = *path == '?' && n == 1 && !*s;
419	memcpy(name, path, n);
420	name[n] = 0;
421	if ((dt = fsfind(name, &ino)) <= 0)
422	    break;
423	path = s;
424    }
425    return dt == DT_REG ? ino : 0;
426}
427
428static int
429fsfind(const char *name, ino_t * ino)
430{
431    char buf[DEV_BSIZE];
432    struct dirent *d;
433    char *s;
434    ssize_t n;
435
436    fs_off = 0;
437    while ((n = fsread(*ino, buf, DEV_BSIZE)) > 0)
438	for (s = buf; s < buf + DEV_BSIZE;) {
439	    d = (void *)s;
440	    if (ls)
441		printf("%s ", d->d_name);
442	    else if (!strcmp(name, d->d_name)) {
443		*ino = d->d_fileno;
444		return d->d_type;
445	    }
446	    s += d->d_reclen;
447	}
448    if (n != -1 && ls)
449	putchar('\n');
450    return 0;
451}
452
453static int
454xfsread(ino_t inode, void *buf, size_t nbyte)
455{
456    if (fsread(inode, buf, nbyte) != nbyte) {
457	printf("Invalid %s\n", "format");
458	return -1;
459    }
460    return 0;
461}
462
463static ssize_t
464fsread(ino_t inode, void *buf, size_t nbyte)
465{
466    static struct fs fs;
467    static struct dinode din;
468    static char *blkbuf;
469    static ufs_daddr_t *indbuf;
470    static ino_t inomap;
471    static ufs_daddr_t blkmap, indmap;
472    static unsigned fsblks;
473    char *s;
474    ufs_daddr_t lbn, addr;
475    size_t n, nb, off;
476
477    if (!dsk.meta) {
478	if (!blkbuf)
479	    blkbuf = malloc(BSIZEMAX);
480	inomap = 0;
481	if (dskread(blkbuf, SBOFF / DEV_BSIZE, SBSIZE / DEV_BSIZE))
482	    return -1;
483	memcpy(&fs, blkbuf, sizeof(fs));
484	if (fs.fs_magic != FS_MAGIC) {
485	    printf("Not ufs\n");
486	    return -1;
487	}
488	fsblks = fs.fs_bsize >> DEV_BSHIFT;
489	dsk.meta = 1;
490    }
491    if (!inode)
492	return 0;
493    if (inomap != inode) {
494	if (dskread(blkbuf, fsbtodb(&fs, ino_to_fsba(&fs, inode)),
495		    fsblks))
496	    return -1;
497	din = ((struct dinode *)blkbuf)[inode % INOPB(&fs)];
498	inomap = inode;
499	fs_off = 0;
500	blkmap = indmap = 0;
501    }
502    s = buf;
503    if (nbyte > (n = din.di_size - fs_off))
504	nbyte = n;
505    nb = nbyte;
506    while (nb) {
507	lbn = lblkno(&fs, fs_off);
508	if (lbn < NDADDR)
509	    addr = din.di_db[lbn];
510	else {
511	    if (indmap != din.di_ib[0]) {
512		if (!indbuf)
513		    indbuf = malloc(BSIZEMAX);
514		if (dskread(indbuf, fsbtodb(&fs, din.di_ib[0]),
515			    fsblks))
516		    return -1;
517		indmap = din.di_ib[0];
518	    }
519	    addr = indbuf[(lbn - NDADDR) % NINDIR(&fs)];
520	}
521	n = dblksize(&fs, &din, lbn);
522	if (blkmap != addr) {
523	    if (dskread(blkbuf, fsbtodb(&fs, addr), n >> DEV_BSHIFT))
524		return -1;
525	    blkmap = addr;
526	}
527	off = blkoff(&fs, fs_off);
528	n -= off;
529	if (n > nb)
530	    n = nb;
531	memcpy(s, blkbuf + off, n);
532	s += n;
533	fs_off += n;
534	nb -= n;
535    }
536    return nbyte;
537}
538
539static int
540dskread(void *buf, unsigned lba, unsigned nblk)
541{
542    static char *sec;
543    struct dos_partition *dp;
544    struct disklabel *d;
545    unsigned sl, i;
546
547    if (!dsk.meta) {
548	if (!sec)
549	    sec = malloc(DEV_BSIZE);
550	dsk.start = 0;
551	if (drvread(sec, DOSBBSECTOR, 1))
552	    return -1;
553	dp = (void *)(sec + DOSPARTOFF);
554	sl = dsk.slice;
555	if (sl < BASE_SLICE) {
556	    for (i = 0; i < NDOSPART; i++)
557		if (dp[i].dp_typ == DOSPTYP_386BSD &&
558		    (dp[i].dp_flag & 0x80 || sl < BASE_SLICE)) {
559		    sl = BASE_SLICE + i;
560		    if (dp[i].dp_flag & 0x80 ||
561			dsk.slice == COMPATIBILITY_SLICE)
562			break;
563		}
564	    if (dsk.slice == WHOLE_DISK_SLICE)
565		dsk.slice = sl;
566	}
567	if (sl != WHOLE_DISK_SLICE) {
568	    if (sl != COMPATIBILITY_SLICE)
569		dp += sl - BASE_SLICE;
570	    if (dp->dp_typ != DOSPTYP_386BSD) {
571		printf("Invalid %s\n", "slice");
572		return -1;
573	    }
574	    dsk.start = dp->dp_start;
575	}
576	if (drvread(sec, dsk.start + LABELSECTOR, 1))
577		return -1;
578	d = (void *)(sec + LABELOFFSET);
579	if (d->d_magic != DISKMAGIC || d->d_magic2 != DISKMAGIC) {
580	    if (dsk.part != RAW_PART) {
581		printf("Invalid %s\n", "label");
582		return -1;
583	    }
584	} else {
585	    if (!dsk.init) {
586		if (d->d_type == DTYPE_SCSI)
587		    dsk.type = MAJ_DA;
588		dsk.init++;
589	    }
590	    if (dsk.part >= d->d_npartitions) {
591		printf("Invalid %s\n", "partition");
592		return -1;
593	    }
594	    dsk.start = d->d_partitions[dsk.part].p_offset;
595	}
596    }
597    return drvread(buf, dsk.start + lba, nblk);
598}
599
600static int
601printf(const char *fmt,...)
602{
603    static const char digits[16] = "0123456789abcdef";
604    va_list ap;
605    char buf[10];
606    char *s;
607    unsigned r, u;
608    int c;
609
610    va_start(ap, fmt);
611    while ((c = *fmt++)) {
612	if (c == '%') {
613	    c = *fmt++;
614	    switch (c) {
615	    case 'c':
616		putchar(va_arg(ap, int));
617		continue;
618	    case 's':
619		for (s = va_arg(ap, char *); *s; s++)
620		    putchar(*s);
621		continue;
622	    case 'u':
623	    case 'x':
624		r = c == 'u' ? 10U : 16U;
625		u = va_arg(ap, unsigned);
626		s = buf;
627		do
628		    *s++ = digits[u % r];
629		while (u /= r);
630		while (--s >= buf)
631		    putchar(*s);
632		continue;
633	    }
634	}
635	putchar(c);
636    }
637    va_end(ap);
638    return 0;
639}
640
641static void
642getstr(char *str, int size)
643{
644    char *s;
645    int c;
646
647    s = str;
648    do {
649	switch (c = getchar()) {
650	case '\b':
651	    if (s > str)
652		s--;
653	    break;
654	case '\n':
655	    *s = 0;
656	    break;
657	default:
658	    if (s - str < size - 1)
659		*s++ = c;
660	}
661	putchar(c);
662    } while (c != '\n');
663}
664
665static int
666putchar(int c)
667{
668    if (c == '\n')
669	xputc('\r');
670    return xputc(c);
671}
672
673static int
674getchar(void)
675{
676    int c;
677
678    c = xgetc(0);
679    if (c == '\r')
680	c = '\n';
681    return c;
682}
683
684static void *
685memcpy(void *dst, const void *src, size_t size)
686{
687    const char *s;
688    char *d;
689
690    for (d = dst, s = src; size; size--)
691	*d++ = *s++;
692    return dst;
693}
694
695static int
696strcmp(const char *s1, const char *s2)
697{
698    for (; *s1 == *s2 && *s1; s1++, s2++);
699    return (u_char)*s1 - (u_char)*s2;
700}
701
702static void *
703malloc(size_t size)
704{
705    static uint32_t next;
706    void *p;
707
708    if (!next)
709	next = roundup2(__base + _end, 0x10000) - __base;
710    p = (void *)next;
711    next += size;
712    return p;
713}
714
715static uint32_t
716memsize(int type)
717{
718    v86.addr = type;
719    v86.eax = 0x8800;
720    v86int();
721    return v86.eax;
722}
723
724static uint32_t
725drvinfo(int drive)
726{
727    v86.addr = 0x13;
728    v86.eax = 0x800;
729    v86.edx = DRV_HARD + drive;
730    v86int();
731    if (V86_CY(v86.efl))
732	return 0x4f010f;
733    return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
734	   (v86.edx & 0xff00) | (v86.ecx & 0x3f);
735}
736
737static int
738drvread(void *buf, unsigned lba, unsigned nblk)
739{
740    static unsigned c = 0x2d5c7c2f;
741
742    printf("%c\b", c = c << 8 | c >> 24);
743    v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
744    v86.addr = 0x604;
745    v86.eax = nblk;
746    v86.ebx = VTOPSEG(buf) << 16 | VTOPOFF(buf);
747    v86.ecx = lba;
748    v86.edx = 0x100 | dsk.drive;
749    v86int();
750    v86.ctl = V86_FLAGS;
751    if (V86_CY(v86.efl)) {
752	printf("Disk error 0x%x (lba=0x%x)\n", v86.eax >> 8 & 0xff,
753	       lba);
754	return -1;
755    }
756    return 0;
757}
758
759static int
760keyhit(unsigned ticks)
761{
762    uint32_t t0, t1;
763
764    t0 = 0;
765    for (;;) {
766	if (xgetc(1))
767	    return 1;
768	t1 = *(uint32_t *)PTOV(0x46c);
769	if (!t0)
770	    t0 = t1;
771	if (t1 < t0 || t1 >= t0 + ticks)
772	    return 0;
773    }
774}
775
776static int
777xputc(int c)
778{
779    if (ioctrl & 0x1)
780	putc(c);
781    if (ioctrl & 0x2)
782	sio_putc(c);
783    return c;
784}
785
786static int
787xgetc(int fn)
788{
789    for (;;) {
790	if (ioctrl & 0x1 && getc(1))
791	    return fn ? 1 : getc(0);
792	if (ioctrl & 0x2 && sio_ischar())
793	    return fn ? 1 : sio_getc();
794	if (fn)
795	    return 0;
796    }
797}
798
799static void
800putc(int c)
801{
802    v86.addr = 0x10;
803    v86.eax = 0xe00 | (c & 0xff);
804    v86.ebx = 0x7;
805    v86int();
806}
807
808static int
809getc(int fn)
810{
811    v86.addr = 0x16;
812    v86.eax = fn << 8;
813    v86int();
814    return fn == 0 ? v86.eax & 0xff : !V86_ZR(v86.efl);
815}
816