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/*

 * mboot.c -- the master bootstrap (boot manager)

 */

#include "stdarg.h"

#include "biolib.h"

#define DEFAULT_PARTITION       ""      /* default boot partition number */

#define LINE_SIZE               80

#define SECTOR_SIZE             512

#define NPE                     (SECTOR_SIZE / sizeof(PartEntry))

#define DESCR_SIZE              20

unsigned int bootDisk = 0;       /* gets loaded by previous stage */

unsigned int startSector = 0;    /* gets loaded by previous stage */

unsigned int numSectors = 0;     /* gets loaded by previous stage */

typedef struct {

  unsigned long type;

  unsigned long start;

  unsigned long size;

  char descr[DESCR_SIZE];

} PartEntry;

PartEntry ptr[NPE];

int strlen(char *str) {

  int i;

  i = 0;

  while (*str++ != '\0') {

    i++;

  }

  return i;

}

void strcpy(char *dst, char *src) {

  while ((*dst++ = *src++) != '\0') ;

}

char getchar(void) {

  return getc();

}

void putchar(char c) {

  if (c == '\n') {

    putchar('\r');

  }

  putc(c);

}

void puts(char *s) {

  char c;

  while ((c = *s++) != '\0') {

    putchar(c);

  }

}

void getline(char *prompt, char *line, int n) {

  int i;

  char c;

  puts(prompt);

  puts(line);

  i = strlen(line);

  while (i < n - 1) {

    c = getchar();

    if (c >= ' ' && c < 0x7F) {

      putchar(c);

      line[i] = c;

      i++;

    } else

    if (c == '\r') {

      putchar('\n');

      line[i] = '\0';

      i = n - 1;

    } else

    if (c == '\b' || c == 0x7F) {

      if (i > 0) {

        putchar('\b');

        putchar(' ');

        putchar('\b');

        i--;

      }

    }

  }

  line[n - 1] = '\0';

}

int countPrintn(long n) {

  long a;

  int res;

  res = 0;

  if (n < 0) {

    res++;

    n = -n;

  }

  a = n / 10;

  if (a != 0) {

    res += countPrintn(a);

  }

  return res + 1;

}

void printn(long n) {

  long a;

  if (n < 0) {

    putchar('-');

    n = -n;

  }

  a = n / 10;

  if (a != 0) {

    printn(a);

  }

  putchar(n % 10 + '0');

}

void printf(char *fmt, ...) {

  va_list ap;

  char c;

  int n;

  unsigned int u;

  char *s;

  char filler;

  int width, count, i;

  va_start(ap, fmt);

  while (1) {

    while ((c = *fmt++) != '%') {

      if (c == '\0') {

        va_end(ap);

        return;

      }

      putchar(c);

    }

    c = *fmt++;

    if (c == '0') {

      filler = '0';

      c = *fmt++;

    } else {

      filler = ' ';

    }

    width = 0;

    if (c >= '0' && c <= '9') {

      width = c - '0';

      c = *fmt++;

    }

    if (c == 'd') {

      n = va_arg(ap, int);

      if (width > 0) {

        count = countPrintn(n);

        for (i = 0; i < width - count; i++) {

          putchar(filler);

        }

      }

      printn(n);

    } else

    if (c == 's') {

      s = va_arg(ap, char *);

      puts(s);

    } else

    if (c == 'c') {

      c = va_arg(ap, char);

      putchar(c);

    } else {

      putchar(c);

    }

  }

}

void halt(void) {

  printf("bootstrap halted\n");

  while (1) ;

}

void readDisk(unsigned int sector, unsigned char *buffer, int count) {

  int result;

  if (sector + count > numSectors) {

    printf("sector number exceeds disk or partition size\n");

    halt();

  }

  result = rwscts(bootDisk, 'r', sector + startSector,

                  (unsigned int) buffer & 0x3FFFFFFF, count);

  if (result != 0) {

    printf("disk read error\n");

    halt();

  }

}

unsigned int entryPoint;        /* where to continue from main() */

int main(void) {

  int i;

  char line[LINE_SIZE];

  char *p;

  int part;

  printf("Bootstrap manager executing...\n");

  strcpy(line, DEFAULT_PARTITION);

  readDisk(1, (unsigned char *) ptr, 1);

  while (1) {

    printf("\nPartitions:\n");

    printf(" # | b | description\n");

    printf("---+---+----------------------\n");

    for (i = 0; i < NPE; i++) {

      if (ptr[i].type != 0) {

        printf("%2d | %s | %s\n",

               i, ptr[i].type & 0x80000000 ? "*" : " ", ptr[i].descr);

      }

    }

    getline("\nBoot partition #: ", line, LINE_SIZE);

    part = 0;

    if (line[0] == '\0') {

      continue;

    }

    p = line;

    while (*p >= '0' && *p <= '9') {

      part = part * 10 + (*p - '0');

      p++;

    }

    if (*p != '\0' || part < 0 || part > 15) {

      printf("illegal partition number\n");

      continue;

    }

    if ((ptr[part].type & 0x7FFFFFFF) == 0) {

      printf("partition %d does not contain a file system\n", part);

      continue;

    }

    if ((ptr[part].type & 0x80000000) == 0) {

      printf("partition %d is not bootable\n", part);

      continue;

    }

    /* load boot sector of selected partition */

    readDisk(ptr[part].start, (unsigned char *) 0xC0000000, 1);

    /* check for signature */

    if ((*((unsigned char *) 0xC0000000 + SECTOR_SIZE - 2) != 0x55) ||

        (*((unsigned char *) 0xC0000000 + SECTOR_SIZE - 1) != 0xAA)) {

      printf("boot sector of partition %d has no signature\n", part);

      continue;

    }

    /* we have a valid boot sector, leave loop */

    break;

  }

  /* boot manager finished, now go executing loaded boot sector */

  startSector = ptr[part].start;

  numSectors = ptr[part].size;

  entryPoint = 0xC0000000;

  return 0;

}