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。]

/* This file contains the main program of the process manager and some related
 * procedures.  When MINIX starts up, the kernel runs for a little while,
 * initializing itself and its tasks, and then it runs PM and FS.  Both PM
 * and FS initialize themselves as far as they can. PM asks the kernel for
 * all free memory and starts serving requests.
 *
 * The entry points into this file are:
 *   main:	starts PM running
 *   setreply:	set the reply to be sent to process making an PM system call
 */

#include "pm.h"
#include <minix/keymap.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <signal.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <string.h>
#include "mproc.h"
#include "param.h"

#include "../../kernel/const.h"
#include "../../kernel/config.h"
#include "../../kernel/type.h"
#include "../../kernel/proc.h"

FORWARD _PROTOTYPE( void get_work, (void)				);
FORWARD _PROTOTYPE( void pm_init, (void)				);
FORWARD _PROTOTYPE( int get_nice_value, (int queue)			);
FORWARD _PROTOTYPE( void get_mem_chunks, (struct memory *mem_chunks) 	);
FORWARD _PROTOTYPE( void patch_mem_chunks, (struct memory *mem_chunks, 
	struct mem_map *map_ptr) 	);

#define click_to_round_k(n) \
	((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))

/*===========================================================================*
 *				main					     *
 *===========================================================================*/
PUBLIC int main()
{
/* Main routine of the process manager. */
  int result, s, proc_nr;
  struct mproc *rmp;
  sigset_t sigset;

  pm_init();			/* initialize process manager tables */

  /* This is PM's main loop-  get work and do it, forever and forever. */
  while (TRUE) {
	get_work();		/* wait for an PM system call */

	/* Check for system notifications first. Special cases. */
	if (call_nr == SYN_ALARM) {
		pm_expire_timers(m_in.NOTIFY_TIMESTAMP);
		result = SUSPEND;		/* don't reply */
	} else if (call_nr == SYS_SIG) {	/* signals pending */
		sigset = m_in.NOTIFY_ARG;
		if (sigismember(&sigset, SIGKSIG))  (void) ksig_pending();
		result = SUSPEND;		/* don't reply */
	}
	/* Else, if the system call number is valid, perform the call. */
	else if ((unsigned) call_nr >= NCALLS) {
		result = ENOSYS;
	} else {
		result = (*call_vec[call_nr])();
	}

	/* Send the results back to the user to indicate completion. */
	if (result != SUSPEND) setreply(who, result);

	swap_in();		/* maybe a process can be swapped in? */

	/* Send out all pending reply messages, including the answer to
	 * the call just made above.  The processes must not be swapped out.
	 */
	for (proc_nr=0, rmp=mproc; proc_nr < NR_PROCS; proc_nr++, rmp++) {
		/* In the meantime, the process may have been killed by a
		 * signal (e.g. if a lethal pending signal was unblocked)
		 * without the PM realizing it. If the slot is no longer in
		 * use or just a zombie, don't try to reply.
		 */
		if ((rmp->mp_flags & (REPLY | ONSWAP | IN_USE | ZOMBIE)) ==
		   (REPLY | IN_USE)) {
			if ((s=send(proc_nr, &rmp->mp_reply)) != OK) {
				panic(__FILE__,"PM can't reply to", proc_nr);
			}
			rmp->mp_flags &= ~REPLY;
		}
	}
  }
  return(OK);
}

/*===========================================================================*
 *				get_work				     *
 *===========================================================================*/
PRIVATE void get_work()
{
/* Wait for the next message and extract useful information from it. */
  if (receive(ANY, &m_in) != OK) panic(__FILE__,"PM receive error", NO_NUM);
  who = m_in.m_source;		/* who sent the message */
  call_nr = m_in.m_type;	/* system call number */

  /* Process slot of caller. Misuse PM's own process slot if the kernel is
   * calling. This can happen in case of synchronous alarms (CLOCK) or or 
   * event like pending kernel signals (SYSTEM).
   */
  mp = &mproc[who < 0 ? PM_PROC_NR : who];
}

/*===========================================================================*
 *				setreply				     *
 *===========================================================================*/
PUBLIC void setreply(proc_nr, result)
int proc_nr;			/* process to reply to */
int result;			/* result of call (usually OK or error #) */
{
/* Fill in a reply message to be sent later to a user process.  System calls
 * may occasionally fill in other fields, this is only for the main return
 * value, and for setting the "must send reply" flag.
 */
  register struct mproc *rmp = &mproc[proc_nr];

  rmp->mp_reply.reply_res = result;
  rmp->mp_flags |= REPLY;	/* reply pending */

  if (rmp->mp_flags & ONSWAP)
	swap_inqueue(rmp);	/* must swap this process back in */
}

/*===========================================================================*
 *				pm_init					     *
 *===========================================================================*/
PRIVATE void pm_init()
{
/* Initialize the process manager. 
 * Memory use info is collected from the boot monitor, the kernel, and
 * all processes compiled into the system image. Initially this information
 * is put into an array mem_chunks. Elements of mem_chunks are struct memory,
 * and hold base, size pairs in units of clicks. This array is small, there
 * should be no more than 8 chunks. After the array of chunks has been built
 * the contents are used to initialize the hole list. Space for the hole list
 * is reserved as an array with twice as many elements as the maximum number
 * of processes allowed. It is managed as a linked list, and elements of the
 * array are struct hole, which, in addition to storage for a base and size in 
 * click units also contain space for a link, a pointer to another element.
*/
  int s;
  static struct boot_image image[NR_BOOT_PROCS];
  register struct boot_image *ip;
  static char core_sigs[] = { SIGQUIT, SIGILL, SIGTRAP, SIGABRT,
			SIGEMT, SIGFPE, SIGUSR1, SIGSEGV, SIGUSR2 };
  static char ign_sigs[] = { SIGCHLD, SIGWINCH };
  static char mess_sigs[] = { SIGTERM, SIGHUP, SIGABRT, SIGQUIT };
  register struct mproc *rmp;
  register int i;
  register char *sig_ptr;
  phys_clicks total_clicks, minix_clicks, free_clicks;
  message mess;
  struct mem_map mem_map[NR_LOCAL_SEGS];
  struct memory mem_chunks[NR_MEMS];

  /* Initialize process table, including timers. */
  for (rmp=&mproc[0]; rmp<&mproc[NR_PROCS]; rmp++) {
	tmr_inittimer(&rmp->mp_timer);
  }

  /* Build the set of signals which cause core dumps, and the set of signals
   * that are by default ignored.
   */
  sigemptyset(&core_sset);
  for (sig_ptr = core_sigs; sig_ptr < core_sigs+sizeof(core_sigs); sig_ptr++)
	sigaddset(&core_sset, *sig_ptr);
  sigemptyset(&ign_sset);
  for (sig_ptr = ign_sigs; sig_ptr < ign_sigs+sizeof(ign_sigs); sig_ptr++)
	sigaddset(&ign_sset, *sig_ptr);

  /* Obtain a copy of the boot monitor parameters and the kernel info struct.  
   * Parse the list of free memory chunks. This list is what the boot monitor 
   * reported, but it must be corrected for the kernel and system processes.
   */
  if ((s=sys_getmonparams(monitor_params, sizeof(monitor_params))) != OK)
      panic(__FILE__,"get monitor params failed",s);
  get_mem_chunks(mem_chunks);
  if ((s=sys_getkinfo(&kinfo)) != OK)
      panic(__FILE__,"get kernel info failed",s);

  /* Get the memory map of the kernel to see how much memory it uses. */
  if ((s=get_mem_map(SYSTASK, mem_map)) != OK)
  	panic(__FILE__,"couldn't get memory map of SYSTASK",s);
  minix_clicks = (mem_map[S].mem_phys+mem_map[S].mem_len)-mem_map[T].mem_phys;
  patch_mem_chunks(mem_chunks, mem_map);

  /* Initialize PM's process table. Request a copy of the system image table