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-rw-r--r--sys/boot/i386/zfsboot/zfsboot.c944
1 files changed, 944 insertions, 0 deletions
diff --git a/sys/boot/i386/zfsboot/zfsboot.c b/sys/boot/i386/zfsboot/zfsboot.c
new file mode 100644
index 0000000..9b0a465
--- /dev/null
+++ b/sys/boot/i386/zfsboot/zfsboot.c
@@ -0,0 +1,944 @@
+/*-
+ * Copyright (c) 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are freely
+ * permitted provided that the above copyright notice and this
+ * paragraph and the following disclaimer are duplicated in all
+ * such forms.
+ *
+ * This software is provided "AS IS" and without any express or
+ * implied warranties, including, without limitation, the implied
+ * warranties of merchantability and fitness for a particular
+ * purpose.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/diskmbr.h>
+#include <sys/reboot.h>
+#include <sys/queue.h>
+
+#include <machine/bootinfo.h>
+#include <machine/elf.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+
+#include <a.out.h>
+
+#include <btxv86.h>
+
+#include "zfsboot.h"
+#include "lib.h"
+
+#define IO_KEYBOARD 1
+#define IO_SERIAL 2
+
+#define SECOND 18 /* Circa that many ticks in a second. */
+
+#define RBX_ASKNAME 0x0 /* -a */
+#define RBX_SINGLE 0x1 /* -s */
+/* 0x2 is reserved for log2(RB_NOSYNC). */
+/* 0x3 is reserved for log2(RB_HALT). */
+/* 0x4 is reserved for log2(RB_INITNAME). */
+#define RBX_DFLTROOT 0x5 /* -r */
+#define RBX_KDB 0x6 /* -d */
+/* 0x7 is reserved for log2(RB_RDONLY). */
+/* 0x8 is reserved for log2(RB_DUMP). */
+/* 0x9 is reserved for log2(RB_MINIROOT). */
+#define RBX_CONFIG 0xa /* -c */
+#define RBX_VERBOSE 0xb /* -v */
+#define RBX_SERIAL 0xc /* -h */
+#define RBX_CDROM 0xd /* -C */
+/* 0xe is reserved for log2(RB_POWEROFF). */
+#define RBX_GDB 0xf /* -g */
+#define RBX_MUTE 0x10 /* -m */
+/* 0x11 is reserved for log2(RB_SELFTEST). */
+/* 0x12 is reserved for boot programs. */
+/* 0x13 is reserved for boot programs. */
+#define RBX_PAUSE 0x14 /* -p */
+#define RBX_QUIET 0x15 /* -q */
+#define RBX_NOINTR 0x1c /* -n */
+/* 0x1d is reserved for log2(RB_MULTIPLE) and is just misnamed here. */
+#define RBX_DUAL 0x1d /* -D */
+/* 0x1f is reserved for log2(RB_BOOTINFO). */
+
+/* pass: -a, -s, -r, -d, -c, -v, -h, -C, -g, -m, -p, -D */
+#define RBX_MASK (OPT_SET(RBX_ASKNAME) | OPT_SET(RBX_SINGLE) | \
+ OPT_SET(RBX_DFLTROOT) | OPT_SET(RBX_KDB ) | \
+ OPT_SET(RBX_CONFIG) | OPT_SET(RBX_VERBOSE) | \
+ OPT_SET(RBX_SERIAL) | OPT_SET(RBX_CDROM) | \
+ OPT_SET(RBX_GDB ) | OPT_SET(RBX_MUTE) | \
+ OPT_SET(RBX_PAUSE) | OPT_SET(RBX_DUAL))
+
+/* Hint to loader that we came from ZFS */
+#define KARGS_FLAGS_ZFS 0x4
+
+#define PATH_CONFIG "/boot.config"
+#define PATH_BOOT3 "/boot/loader"
+#define PATH_KERNEL "/boot/kernel/kernel"
+
+#define ARGS 0x900
+#define NOPT 14
+#define NDEV 3
+#define MEM_BASE 0x12
+#define MEM_EXT 0x15
+#define V86_CY(x) ((x) & 1)
+#define V86_ZR(x) ((x) & 0x40)
+
+#define DRV_HARD 0x80
+#define DRV_MASK 0x7f
+
+#define TYPE_AD 0
+#define TYPE_DA 1
+#define TYPE_MAXHARD TYPE_DA
+#define TYPE_FD 2
+
+#define OPT_SET(opt) (1 << (opt))
+#define OPT_CHECK(opt) ((opts) & OPT_SET(opt))
+
+extern uint32_t _end;
+
+static const char optstr[NOPT] = "DhaCcdgmnpqrsv"; /* Also 'P', 'S' */
+static const unsigned char flags[NOPT] = {
+ RBX_DUAL,
+ RBX_SERIAL,
+ RBX_ASKNAME,
+ RBX_CDROM,
+ RBX_CONFIG,
+ RBX_KDB,
+ RBX_GDB,
+ RBX_MUTE,
+ RBX_NOINTR,
+ RBX_PAUSE,
+ RBX_QUIET,
+ RBX_DFLTROOT,
+ RBX_SINGLE,
+ RBX_VERBOSE
+};
+
+static const char *const dev_nm[NDEV] = {"ad", "da", "fd"};
+static const unsigned char dev_maj[NDEV] = {30, 4, 2};
+
+struct dsk {
+ unsigned drive;
+ unsigned type;
+ unsigned unit;
+ unsigned slice;
+ unsigned part;
+ unsigned start;
+ int init;
+};
+static char cmd[512];
+static char kname[1024];
+static uint32_t opts;
+static int comspeed = SIOSPD;
+static struct bootinfo bootinfo;
+static uint32_t bootdev;
+static uint8_t ioctrl = IO_KEYBOARD;
+
+/* Buffers that must not span a 64k boundary. */
+#define READ_BUF_SIZE 8192
+struct dmadat {
+ char rdbuf[READ_BUF_SIZE]; /* for reading large things */
+ char secbuf[READ_BUF_SIZE]; /* for MBR/disklabel */
+};
+static struct dmadat *dmadat;
+
+void exit(int);
+static void load(void);
+static int parse(void);
+static void printf(const char *,...);
+static void putchar(int);
+static uint32_t memsize(void);
+static int drvread(struct dsk *, void *, unsigned, unsigned);
+static int keyhit(unsigned);
+static int xputc(int);
+static int xgetc(int);
+static int getc(int);
+
+static void memcpy(void *, const void *, int);
+static void
+memcpy(void *dst, const void *src, int len)
+{
+ const char *s = src;
+ char *d = dst;
+
+ while (len--)
+ *d++ = *s++;
+}
+
+static void
+strcpy(char *dst, const char *src)
+{
+ while (*src)
+ *dst++ = *src++;
+ *dst++ = 0;
+}
+
+static void
+strcat(char *dst, const char *src)
+{
+ while (*dst)
+ dst++;
+ while (*src)
+ *dst++ = *src++;
+ *dst++ = 0;
+}
+
+static int
+strcmp(const char *s1, const char *s2)
+{
+ for (; *s1 == *s2 && *s1; s1++, s2++);
+ return (unsigned char)*s1 - (unsigned char)*s2;
+}
+
+static const char *
+strchr(const char *s, char ch)
+{
+ for (; *s; s++)
+ if (*s == ch)
+ return s;
+ return 0;
+}
+
+static int
+memcmp(const void *p1, const void *p2, size_t n)
+{
+ const char *s1 = (const char *) p1;
+ const char *s2 = (const char *) p2;
+ for (; n > 0 && *s1 == *s2; s1++, s2++, n--);
+ if (n)
+ return (unsigned char)*s1 - (unsigned char)*s2;
+ else
+ return 0;
+}
+
+static void
+memset(void *p, char val, size_t n)
+{
+ char *s = (char *) p;
+ while (n--)
+ *s++ = val;
+}
+
+static void *
+malloc(size_t n)
+{
+ static char *heap_next;
+ static char *heap_end;
+
+ if (!heap_next) {
+ heap_next = (char *) dmadat + sizeof(*dmadat);
+ heap_end = (char *) (640*1024);
+ }
+
+ char *p = heap_next;
+ if (p + n > heap_end) {
+ printf("malloc failure\n");
+ for (;;)
+ ;
+ return 0;
+ }
+ heap_next += n;
+ return p;
+}
+
+static size_t
+strlen(const char *s)
+{
+ size_t len = 0;
+ while (*s++)
+ len++;
+ return len;
+}
+
+static char *
+strdup(const char *s)
+{
+ char *p = malloc(strlen(s) + 1);
+ strcpy(p, s);
+ return p;
+}
+
+#include "zfsimpl.c"
+
+/*
+ * Read from a dnode (which must be from a ZPL filesystem).
+ */
+static int
+zfs_read(spa_t *spa, const dnode_phys_t *dnode, off_t *offp, void *start, size_t size)
+{
+ const znode_phys_t *zp = (const znode_phys_t *) dnode->dn_bonus;
+ size_t n;
+ int rc;
+
+ n = size;
+ if (*offp + n > zp->zp_size)
+ n = zp->zp_size - *offp;
+
+ rc = dnode_read(spa, dnode, *offp, start, n);
+ if (rc)
+ return (-1);
+ *offp += n;
+
+ return (n);
+}
+
+/*
+ * Current ZFS pool
+ */
+spa_t *spa;
+
+/*
+ * A wrapper for dskread that doesn't have to worry about whether the
+ * buffer pointer crosses a 64k boundary.
+ */
+static int
+vdev_read(vdev_t *vdev, void *priv, off_t off, void *buf, size_t bytes)
+{
+ char *p;
+ unsigned int lba, nb;
+ struct dsk *dsk = (struct dsk *) priv;
+
+ if ((off & (DEV_BSIZE - 1)) || (bytes & (DEV_BSIZE - 1)))
+ return -1;
+
+ p = buf;
+ lba = off / DEV_BSIZE;
+ while (bytes > 0) {
+ nb = bytes / DEV_BSIZE;
+ if (nb > READ_BUF_SIZE / DEV_BSIZE)
+ nb = READ_BUF_SIZE / DEV_BSIZE;
+ if (drvread(dsk, dmadat->rdbuf, lba, nb))
+ return -1;
+ memcpy(p, dmadat->rdbuf, nb * DEV_BSIZE);
+ p += nb * DEV_BSIZE;
+ lba += nb;
+ bytes -= nb * DEV_BSIZE;
+ }
+
+ return 0;
+}
+
+static int
+xfsread(const dnode_phys_t *dnode, off_t *offp, void *buf, size_t nbyte)
+{
+ if ((size_t)zfs_read(spa, dnode, offp, buf, nbyte) != nbyte) {
+ printf("Invalid %s\n", "format");
+ return -1;
+ }
+ return 0;
+}
+
+static inline uint32_t
+memsize(void)
+{
+ v86.addr = MEM_EXT;
+ v86.eax = 0x8800;
+ v86int();
+ return v86.eax;
+}
+
+static inline void
+getstr(void)
+{
+ char *s;
+ int c;
+
+ s = cmd;
+ for (;;) {
+ switch (c = xgetc(0)) {
+ case 0:
+ break;
+ case '\177':
+ case '\b':
+ if (s > cmd) {
+ s--;
+ printf("\b \b");
+ }
+ break;
+ case '\n':
+ case '\r':
+ *s = 0;
+ return;
+ default:
+ if (s - cmd < sizeof(cmd) - 1)
+ *s++ = c;
+ putchar(c);
+ }
+ }
+}
+
+static inline void
+putc(int c)
+{
+ v86.addr = 0x10;
+ v86.eax = 0xe00 | (c & 0xff);
+ v86.ebx = 0x7;
+ v86int();
+}
+
+/*
+ * Try to detect a device supported by the legacy int13 BIOS
+ */
+static int
+int13probe(int drive)
+{
+ v86.ctl = V86_FLAGS;
+ v86.addr = 0x13;
+ v86.eax = 0x800;
+ v86.edx = drive;
+ v86int();
+
+ if (!(v86.efl & 0x1) && /* carry clear */
+ ((v86.edx & 0xff) != (drive & DRV_MASK))) { /* unit # OK */
+ if ((v86.ecx & 0x3f) == 0) { /* absurd sector size */
+ return(0); /* skip device */
+ }
+ return (1);
+ }
+ return(0);
+}
+
+static void
+probe_drive(struct dsk *dsk, spa_t **spap)
+{
+ struct dos_partition *dp;
+ char *sec;
+ unsigned i;
+
+ if (!int13probe(dsk->drive))
+ return;
+
+ /*
+ * If we find a vdev on the whole disk, stop here. Otherwise dig
+ * out the MBR and probe each slice in turn for a vdev.
+ */
+ if (vdev_probe(vdev_read, dsk, spap) == 0)
+ return;
+
+ sec = dmadat->secbuf;
+ dsk->start = 0;
+ if (drvread(dsk, sec, DOSBBSECTOR, 1))
+ return;
+ dp = (void *)(sec + DOSPARTOFF);
+
+ for (i = 0; i < NDOSPART; i++) {
+ if (!dp[i].dp_typ)
+ continue;
+ dsk->start = dp[i].dp_start;
+ if (vdev_probe(vdev_read, dsk, spap) == 0) {
+ /*
+ * We record the first pool we find (we will try to boot
+ * from that one.
+ */
+ spap = 0;
+
+ /*
+ * This slice had a vdev. We need a new dsk structure now
+ * sice the vdev now owns this one.
+ */
+ struct dsk *newdsk;
+ newdsk = malloc(sizeof(struct dsk));
+ *newdsk = *dsk;
+ dsk = newdsk;
+ }
+ }
+}
+
+int
+main(void)
+{
+ int autoboot, i;
+ dnode_phys_t dn;
+ off_t off;
+ struct dsk *dsk;
+
+ dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
+ v86.ctl = V86_FLAGS;
+
+ dsk = malloc(sizeof(struct dsk));
+ dsk->drive = *(uint8_t *)PTOV(ARGS);
+ dsk->type = dsk->drive & DRV_HARD ? TYPE_AD : TYPE_FD;
+ dsk->unit = dsk->drive & DRV_MASK;
+ dsk->slice = *(uint8_t *)PTOV(ARGS + 1) + 1;
+ dsk->part = 0;
+ dsk->start = 0;
+ dsk->init = 0;
+
+ bootinfo.bi_version = BOOTINFO_VERSION;
+ bootinfo.bi_size = sizeof(bootinfo);
+ bootinfo.bi_basemem = 0; /* XXX will be filled by loader or kernel */
+ bootinfo.bi_extmem = memsize();
+ bootinfo.bi_memsizes_valid++;
+ bootinfo.bi_bios_dev = dsk->drive;
+
+ bootdev = MAKEBOOTDEV(dev_maj[dsk->type],
+ dsk->slice, dsk->unit, dsk->part),
+
+ /* Process configuration file */
+
+ autoboot = 1;
+
+ zfs_init();
+
+ /*
+ * Probe the boot drive first - we will try to boot from whatever
+ * pool we find on that drive.
+ */
+ probe_drive(dsk, &spa);
+
+ /*
+ * Probe the rest of the drives that the bios knows about. This
+ * will find any other available pools and it may fill in missing
+ * vdevs for the boot pool.
+ */
+ for (i = 0; i < 4; i++) {
+ if ((i | DRV_HARD) == *(uint8_t *)PTOV(ARGS))
+ continue;
+
+ dsk = malloc(sizeof(struct dsk));
+ dsk->drive = i | DRV_HARD;
+ dsk->type = dsk->drive & TYPE_AD;
+ dsk->unit = i;
+ dsk->slice = 0;
+ dsk->part = 0;
+ dsk->start = 0;
+ dsk->init = 0;
+ probe_drive(dsk, 0);
+ }
+
+ /*
+ * If we didn't find a pool on the boot drive, default to the
+ * first pool we found, if any.
+ */
+ if (!spa) {
+ spa = STAILQ_FIRST(&zfs_pools);
+ if (!spa) {
+ printf("No ZFS pools located, can't boot\n");
+ for (;;)
+ ;
+ }
+ }
+
+ zfs_mount_pool(spa);
+
+ if (zfs_lookup(spa, PATH_CONFIG, &dn) == 0) {
+ off = 0;
+ xfsread(&dn, &off, cmd, sizeof(cmd));
+ }
+
+ if (*cmd) {
+ if (parse())
+ autoboot = 0;
+ if (!OPT_CHECK(RBX_QUIET))
+ printf("%s: %s", PATH_CONFIG, cmd);
+ /* Do not process this command twice */
+ *cmd = 0;
+ }
+
+ /*
+ * Try to exec stage 3 boot loader. If interrupted by a keypress,
+ * or in case of failure, try to load a kernel directly instead.
+ */
+
+ if (autoboot && !*kname) {
+ memcpy(kname, PATH_BOOT3, sizeof(PATH_BOOT3));
+ if (!keyhit(3*SECOND)) {
+ load();
+ memcpy(kname, PATH_KERNEL, sizeof(PATH_KERNEL));
+ }
+ }
+
+ /* Present the user with the boot2 prompt. */
+
+ for (;;) {
+ if (!autoboot || !OPT_CHECK(RBX_QUIET))
+ printf("\nFreeBSD/i386 boot\n"
+ "Default: %s:%s\n"
+ "boot: ",
+ spa->spa_name, kname);
+ if (ioctrl & IO_SERIAL)
+ sio_flush();
+ if (!autoboot || keyhit(5*SECOND))
+ getstr();
+ else if (!autoboot || !OPT_CHECK(RBX_QUIET))
+ putchar('\n');
+ autoboot = 0;
+ if (parse())
+ putchar('\a');
+ else
+ load();
+ }
+}
+
+/* XXX - Needed for btxld to link the boot2 binary; do not remove. */
+void
+exit(int x)
+{
+}
+
+static void
+load(void)
+{
+ union {
+ struct exec ex;
+ Elf32_Ehdr eh;
+ } hdr;
+ static Elf32_Phdr ep[2];
+ static Elf32_Shdr es[2];
+ caddr_t p;
+ dnode_phys_t dn;
+ off_t off;
+ uint32_t addr, x;
+ int fmt, i, j;
+
+ if (zfs_lookup(spa, kname, &dn)) {
+ return;
+ }
+ off = 0;
+ if (xfsread(&dn, &off, &hdr, sizeof(hdr)))
+ return;
+ if (N_GETMAGIC(hdr.ex) == ZMAGIC)
+ fmt = 0;
+ else if (IS_ELF(hdr.eh))
+ fmt = 1;
+ else {
+ printf("Invalid %s\n", "format");
+ return;
+ }
+ if (fmt == 0) {
+ addr = hdr.ex.a_entry & 0xffffff;
+ p = PTOV(addr);
+ off = PAGE_SIZE;
+ if (xfsread(&dn, &off, p, hdr.ex.a_text))
+ return;
+ p += roundup2(hdr.ex.a_text, PAGE_SIZE);
+ if (xfsread(&dn, &off, p, hdr.ex.a_data))
+ return;
+ p += hdr.ex.a_data + roundup2(hdr.ex.a_bss, PAGE_SIZE);
+ bootinfo.bi_symtab = VTOP(p);
+ memcpy(p, &hdr.ex.a_syms, sizeof(hdr.ex.a_syms));
+ p += sizeof(hdr.ex.a_syms);
+ if (hdr.ex.a_syms) {
+ if (xfsread(&dn, &off, p, hdr.ex.a_syms))
+ return;
+ p += hdr.ex.a_syms;
+ if (xfsread(&dn, &off, p, sizeof(int)))
+ return;
+ x = *(uint32_t *)p;
+ p += sizeof(int);
+ x -= sizeof(int);
+ if (xfsread(&dn, &off, p, x))
+ return;
+ p += x;
+ }
+ } else {
+ off = hdr.eh.e_phoff;
+ for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) {
+ if (xfsread(&dn, &off, ep + j, sizeof(ep[0])))
+ return;
+ if (ep[j].p_type == PT_LOAD)
+ j++;
+ }
+ for (i = 0; i < 2; i++) {
+ p = PTOV(ep[i].p_paddr & 0xffffff);
+ off = ep[i].p_offset;
+ if (xfsread(&dn, &off, p, ep[i].p_filesz))
+ return;
+ }
+ p += roundup2(ep[1].p_memsz, PAGE_SIZE);
+ bootinfo.bi_symtab = VTOP(p);
+ if (hdr.eh.e_shnum == hdr.eh.e_shstrndx + 3) {
+ off = hdr.eh.e_shoff + sizeof(es[0]) *
+ (hdr.eh.e_shstrndx + 1);
+ if (xfsread(&dn, &off, &es, sizeof(es)))
+ return;
+ for (i = 0; i < 2; i++) {
+ memcpy(p, &es[i].sh_size, sizeof(es[i].sh_size));
+ p += sizeof(es[i].sh_size);
+ off = es[i].sh_offset;
+ if (xfsread(&dn, &off, p, es[i].sh_size))
+ return;
+ p += es[i].sh_size;
+ }
+ }
+ addr = hdr.eh.e_entry & 0xffffff;
+ }
+ bootinfo.bi_esymtab = VTOP(p);
+ bootinfo.bi_kernelname = VTOP(kname);
+ __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
+ bootdev,
+ KARGS_FLAGS_ZFS,
+ (uint32_t) spa->spa_guid,
+ (uint32_t) (spa->spa_guid >> 32),
+ VTOP(&bootinfo));
+}
+
+static int
+parse()
+{
+ char *arg = cmd;
+ char *ep, *p, *q;
+ const char *cp;
+ //unsigned int drv;
+ int c, i, j;
+
+ while ((c = *arg++)) {
+ if (c == ' ' || c == '\t' || c == '\n')
+ continue;
+ for (p = arg; *p && *p != '\n' && *p != ' ' && *p != '\t'; p++);
+ ep = p;
+ if (*p)
+ *p++ = 0;
+ if (c == '-') {
+ while ((c = *arg++)) {
+ if (c == 'P') {
+ if (*(uint8_t *)PTOV(0x496) & 0x10) {
+ cp = "yes";
+ } else {
+ opts |= OPT_SET(RBX_DUAL) | OPT_SET(RBX_SERIAL);
+ cp = "no";
+ }
+ printf("Keyboard: %s\n", cp);
+ continue;
+ } else if (c == 'S') {
+ j = 0;
+ while ((unsigned int)(i = *arg++ - '0') <= 9)
+ j = j * 10 + i;
+ if (j > 0 && i == -'0') {
+ comspeed = j;
+ break;
+ }
+ /* Fall through to error below ('S' not in optstr[]). */
+ }
+ for (i = 0; c != optstr[i]; i++)
+ if (i == NOPT - 1)
+ return -1;
+ opts ^= OPT_SET(flags[i]);
+ }
+ ioctrl = OPT_CHECK(RBX_DUAL) ? (IO_SERIAL|IO_KEYBOARD) :
+ OPT_CHECK(RBX_SERIAL) ? IO_SERIAL : IO_KEYBOARD;
+ if (ioctrl & IO_SERIAL)
+ sio_init(115200 / comspeed);
+ } if (c == '?') {
+ dnode_phys_t dn;
+
+ if (zfs_lookup(spa, arg, &dn) == 0) {
+ zap_list(spa, &dn);
+ }
+ return -1;
+ } else {
+ arg--;
+
+ /*
+ * Report pool status if the comment is 'status'. Lets
+ * hope no-one wants to load /status as a kernel.
+ */
+ if (!strcmp(arg, "status")) {
+ spa_all_status();
+ return -1;
+ }
+
+ /*
+ * If there is a colon, switch pools.
+ */
+ q = (char *) strchr(arg, ':');
+ if (q) {
+ spa_t *newspa;
+
+ *q++ = 0;
+ newspa = spa_find_by_name(arg);
+ if (newspa) {
+ spa = newspa;
+ zfs_mount_pool(spa);
+ } else {
+ printf("\nCan't find ZFS pool %s\n", arg);
+ return -1;
+ }
+ arg = q;
+ }
+ if ((i = ep - arg)) {
+ if ((size_t)i >= sizeof(kname))
+ return -1;
+ memcpy(kname, arg, i + 1);
+ }
+ }
+ arg = p;
+ }
+ return 0;
+}
+
+static void
+printf(const char *fmt,...)
+{
+ va_list ap;
+ char buf[10];
+ char *s;
+ unsigned u;
+ int c;
+ int minus;
+ int prec;
+ int len;
+ int pad;
+
+ va_start(ap, fmt);
+ while ((c = *fmt++)) {
+ if (c == '%') {
+ minus = 0;
+ prec = 0;
+ nextfmt:
+ c = *fmt++;
+ switch (c) {
+ case '-':
+ minus = 1;
+ goto nextfmt;
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ prec = 10 * prec + (c - '0');
+ goto nextfmt;
+ case 'c':
+ putchar(va_arg(ap, int));
+ continue;
+ case 's':
+ s = va_arg(ap, char *);
+ if (prec) {
+ len = strlen(s);
+ if (len < prec)
+ pad = prec - len;
+ else
+ pad = 0;
+ if (minus)
+ while (pad--)
+ putchar(' ');
+ for (; *s; s++)
+ putchar(*s);
+ if (!minus)
+ while (pad--)
+ putchar(' ');
+ } else {
+ for (; *s; s++)
+ putchar(*s);
+ }
+ continue;
+ case 'u':
+ u = va_arg(ap, unsigned);
+ s = buf;
+ do
+ *s++ = '0' + u % 10U;
+ while (u /= 10U);
+ while (--s >= buf)
+ putchar(*s);
+ continue;
+ }
+ }
+ putchar(c);
+ }
+ va_end(ap);
+ return;
+}
+
+static void
+putchar(int c)
+{
+ if (c == '\n')
+ xputc('\r');
+ xputc(c);
+}
+
+static int
+drvread(struct dsk *dsk, void *buf, unsigned lba, unsigned nblk)
+{
+ static unsigned c = 0x2d5c7c2f;
+
+ lba += dsk->start;
+ if (!OPT_CHECK(RBX_QUIET))
+ printf("%c\b", c = c << 8 | c >> 24);
+ v86.ctl = V86_ADDR | V86_CALLF | V86_FLAGS;
+ v86.addr = XREADORG; /* call to xread in boot1 */
+ v86.es = VTOPSEG(buf);
+ v86.eax = lba;
+ v86.ebx = VTOPOFF(buf);
+ v86.ecx = lba >> 16;
+ v86.edx = nblk << 8 | dsk->drive;
+ v86int();
+ v86.ctl = V86_FLAGS;
+ if (V86_CY(v86.efl)) {
+ printf("error %u lba %u\n", v86.eax >> 8 & 0xff, lba);
+ return -1;
+ }
+ return 0;
+}
+
+static int
+keyhit(unsigned ticks)
+{
+ uint32_t t0, t1;
+
+ if (OPT_CHECK(RBX_NOINTR))
+ return 0;
+ t0 = 0;
+ for (;;) {
+ if (xgetc(1))
+ return 1;
+ t1 = *(uint32_t *)PTOV(0x46c);
+ if (!t0)
+ t0 = t1;
+ if (t1 < t0 || t1 >= t0 + ticks)
+ return 0;
+ }
+}
+
+static int
+xputc(int c)
+{
+ if (ioctrl & IO_KEYBOARD)
+ putc(c);
+ if (ioctrl & IO_SERIAL)
+ sio_putc(c);
+ return c;
+}
+
+static int
+xgetc(int fn)
+{
+ if (OPT_CHECK(RBX_NOINTR))
+ return 0;
+ for (;;) {
+ if (ioctrl & IO_KEYBOARD && getc(1))
+ return fn ? 1 : getc(0);
+ if (ioctrl & IO_SERIAL && sio_ischar())
+ return fn ? 1 : sio_getc();
+ if (fn)
+ return 0;
+ }
+}
+
+static int
+getc(int fn)
+{
+ /*
+ * The extra comparison against zero is an attempt to work around
+ * what appears to be a bug in QEMU and Bochs. Both emulators
+ * sometimes report a key-press with scancode one and ascii zero
+ * when no such key is pressed in reality. As far as I can tell,
+ * this only happens shortly after a reboot.
+ */
+ v86.addr = 0x16;
+ v86.eax = fn << 8;
+ v86int();
+ return fn == 0 ? v86.eax & 0xff : (!V86_ZR(v86.efl) && (v86.eax & 0xff));
+}
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