main.c

Minix3.11的源码。[MINIX 3是一个为高可靠性应用而设计的自由且简洁的类UNIX系统。]

   * that is defined at the kernel level to see which slots to fill in.
   */
  if (OK != (s=sys_getimage(image))) 
  	panic(__FILE__,"couldn't get image table: %d\n", s);
  procs_in_use = 0;				/* start populating table */
  printf("Building process table:");		/* show what's happening */
  for (ip = &image[0]; ip < &image[NR_BOOT_PROCS]; ip++) {		
  	if (ip->proc_nr >= 0) {			/* task have negative nrs */
  		procs_in_use += 1;		/* found user process */

		/* Set process details found in the image table. */
		rmp = &mproc[ip->proc_nr];	
  		strncpy(rmp->mp_name, ip->proc_name, PROC_NAME_LEN); 
		rmp->mp_parent = RS_PROC_NR;
		rmp->mp_nice = get_nice_value(ip->priority);
  		sigemptyset(&rmp->mp_sig2mess);
  		sigemptyset(&rmp->mp_ignore);	
  		sigemptyset(&rmp->mp_sigmask);
  		sigemptyset(&rmp->mp_catch);
		if (ip->proc_nr == INIT_PROC_NR) {	/* user process */
  			rmp->mp_pid = INIT_PID;
			rmp->mp_flags |= IN_USE; 
		}
		else {					/* system process */
  			rmp->mp_pid = get_free_pid();
			rmp->mp_flags |= IN_USE | DONT_SWAP | PRIV_PROC; 
#if DEAD_CODE
  			for (sig_ptr = mess_sigs; 
				sig_ptr < mess_sigs+sizeof(mess_sigs); 
				sig_ptr++)
			sigaddset(&rmp->mp_sig2mess, *sig_ptr);
#endif
		}

  		/* Get memory map for this process from the kernel. */
		if ((s=get_mem_map(ip->proc_nr, rmp->mp_seg)) != OK)
  			panic(__FILE__,"couldn't get process entry",s);
		if (rmp->mp_seg[T].mem_len != 0) rmp->mp_flags |= SEPARATE;
		minix_clicks += rmp->mp_seg[S].mem_phys + 
			rmp->mp_seg[S].mem_len - rmp->mp_seg[T].mem_phys;
  		patch_mem_chunks(mem_chunks, rmp->mp_seg);

		/* Tell FS about this system process. */
		mess.PR_PROC_NR = ip->proc_nr;
		mess.PR_PID = rmp->mp_pid;
  		if (OK != (s=send(FS_PROC_NR, &mess)))
			panic(__FILE__,"can't sync up with FS", s);
  		printf(" %s", ip->proc_name);	/* display process name */
  	}
  }
  printf(".\n");				/* last process done */

  /* Override some details. INIT, PM, FS and RS are somewhat special. */
  mproc[PM_PROC_NR].mp_pid = PM_PID;		/* PM has magic pid */
  mproc[RS_PROC_NR].mp_parent = INIT_PROC_NR;	/* INIT is root */
  sigfillset(&mproc[PM_PROC_NR].mp_ignore); 	/* guard against signals */
  sigfillset(&mproc[FS_PROC_NR].mp_sig2mess); 	/* forward signals */
  sigfillset(&mproc[TTY_PROC_NR].mp_sig2mess); 	/* forward signals */
  sigfillset(&mproc[MEM_PROC_NR].mp_sig2mess); 	/* forward signals */

  /* Tell FS that no more system processes follow and synchronize. */
  mess.PR_PROC_NR = NONE;
  if (sendrec(FS_PROC_NR, &mess) != OK || mess.m_type != OK)
	panic(__FILE__,"can't sync up with FS", NO_NUM);

#if ENABLE_BOOTDEV
  /* Possibly we must correct the memory chunks for the boot device. */
  if (kinfo.bootdev_size > 0) {
      mem_map[T].mem_phys = kinfo.bootdev_base >> CLICK_SHIFT;
      mem_map[T].mem_len = 0;
      mem_map[D].mem_len = (kinfo.bootdev_size+CLICK_SIZE-1) >> CLICK_SHIFT;
      patch_mem_chunks(mem_chunks, mem_map);
  }
#endif /* ENABLE_BOOTDEV */

  /* Initialize tables to all physical memory and print memory information. */
  printf("Physical memory:");
  mem_init(mem_chunks, &free_clicks);
  total_clicks = minix_clicks + free_clicks;
  printf(" total %u KB,", click_to_round_k(total_clicks));
  printf(" system %u KB,", click_to_round_k(minix_clicks));
  printf(" free %u KB.\n", click_to_round_k(free_clicks));
}

/*===========================================================================*
 *				get_nice_value				     *
 *===========================================================================*/
PRIVATE int get_nice_value(queue)
int queue;				/* store mem chunks here */
{
/* Processes in the boot image have a priority assigned. The PM doesn't know
 * about priorities, but uses 'nice' values instead. The priority is between 
 * MIN_USER_Q and MAX_USER_Q. We have to scale between PRIO_MIN and PRIO_MAX.
 */ 
  int nice_val = (queue - USER_Q) * (PRIO_MAX-PRIO_MIN+1) / 
      (MIN_USER_Q-MAX_USER_Q+1);
  if (nice_val > PRIO_MAX) nice_val = PRIO_MAX;	/* shouldn't happen */
  if (nice_val < PRIO_MIN) nice_val = PRIO_MIN;	/* shouldn't happen */
  return nice_val;
}

#if _WORD_SIZE == 2
/* In real mode only 1M can be addressed, and in 16-bit protected we can go
 * no further than we can count in clicks.  (The 286 is further limited by
 * its 24 bit address bus, but we can assume in that case that no more than
 * 16M memory is reported by the BIOS.)
 */
#define MAX_REAL	0x00100000L
#define MAX_16BIT	(0xFFF0L << CLICK_SHIFT)
#endif

/*===========================================================================*
 *				get_mem_chunks				     *
 *===========================================================================*/
PRIVATE void get_mem_chunks(mem_chunks)
struct memory *mem_chunks;			/* store mem chunks here */
{
/* Initialize the free memory list from the 'memory' boot variable.  Translate
 * the byte offsets and sizes in this list to clicks, properly truncated. Also
 * make sure that we don't exceed the maximum address space of the 286 or the
 * 8086, i.e. when running in 16-bit protected mode or real mode.
 */
  long base, size, limit;
  char *s, *end;			/* use to parse boot variable */ 
  int i, done = 0;
  struct memory *memp;
#if _WORD_SIZE == 2
  unsigned long max_address;
  struct machine machine;
  if (OK != (i=sys_getmachine(&machine)))
	panic(__FILE__, "sys_getmachine failed", i);
#endif

  /* Initialize everything to zero. */
  for (i = 0; i < NR_MEMS; i++) {
	memp = &mem_chunks[i];		/* next mem chunk is stored here */
	memp->base = memp->size = 0;
  }
  
  /* The available memory is determined by MINIX' boot loader as a list of 
   * (base:size)-pairs in boothead.s. The 'memory' boot variable is set in
   * in boot.s.  The format is "b0:s0,b1:s1,b2:s2", where b0:s0 is low mem,
   * b1:s1 is mem between 1M and 16M, b2:s2 is mem above 16M. Pairs b1:s1 
   * and b2:s2 are combined if the memory is adjacent. 
   */
  s = find_param("memory");		/* get memory boot variable */
  for (i = 0; i < NR_MEMS && !done; i++) {
	memp = &mem_chunks[i];		/* next mem chunk is stored here */
	base = size = 0;		/* initialize next base:size pair */
	if (*s != 0) {			/* get fresh data, unless at end */	

	    /* Read fresh base and expect colon as next char. */ 
	    base = strtoul(s, &end, 0x10);		/* get number */
	    if (end != s && *end == ':') s = ++end;	/* skip ':' */ 
	    else *s=0;			/* terminate, should not happen */

	    /* Read fresh size and expect comma or assume end. */ 
	    size = strtoul(s, &end, 0x10);		/* get number */
	    if (end != s && *end == ',') s = ++end;	/* skip ',' */
	    else done = 1;
	}
	limit = base + size;	
#if _WORD_SIZE == 2
	max_address = machine.protected ? MAX_16BIT : MAX_REAL;
	if (limit > max_address) limit = max_address;
#endif
	base = (base + CLICK_SIZE-1) & ~(long)(CLICK_SIZE-1);
	limit &= ~(long)(CLICK_SIZE-1);
	if (limit <= base) continue;
	memp->base = base >> CLICK_SHIFT;
	memp->size = (limit - base) >> CLICK_SHIFT;
  }
}

/*===========================================================================*
 *				patch_mem_chunks			     *
 *===========================================================================*/
PRIVATE void patch_mem_chunks(mem_chunks, map_ptr)
struct memory *mem_chunks;			/* store mem chunks here */
struct mem_map *map_ptr;			/* memory to remove */
{
/* Remove server memory from the free memory list. The boot monitor
 * promises to put processes at the start of memory chunks. The 
 * tasks all use same base address, so only the first task changes
 * the memory lists. The servers and init have their own memory
 * spaces and their memory will be removed from the list. 
 */
  struct memory *memp;
  for (memp = mem_chunks; memp < &mem_chunks[NR_MEMS]; memp++) {
	if (memp->base == map_ptr[T].mem_phys) {
		memp->base += map_ptr[T].mem_len + map_ptr[D].mem_len;
		memp->size -= map_ptr[T].mem_len + map_ptr[D].mem_len;
	}
  }
}