m_utek.c

unix系统下top命令的源代码

	 *  Place pointers to each valid proc structure in pref[].
	 *  Process slots that are actually in use have a non-zero
	 *  status field.  Processes with SSYS set are system
	 *  processes---these get ignored unless show_sysprocs is set.
	 */
	if (pp->p_stat != 0 && pp->p_pid != 0 &&
	    (show_system || ((pp->p_flag & SSYS) == 0)))
	{
	    total_procs++;
	    process_states[pp->p_stat]++;
	    if ((pp->p_stat != SZOMB) &&
		(show_idle || (pp->p_pctcpu != 0) || (pp->p_stat == SRUN)) &&
		(!show_uid || pp->p_uid == (uid_t)sel->uid))
	    {
		*prefp++ = pp;
		active_procs++;
	    }
	}
    }

    /* if requested, sort the "interesting" processes */
    if (compare != NULL)
    {
	qsort((char *)pref, active_procs, sizeof(struct proc *), compare);
    }

    /* remember active and total counts */
    si->p_total = total_procs;
    si->p_active = pref_len = active_procs;

    /* pass back a handle */
    handle.next_proc = pref;
    handle.remaining = active_procs;
    return((caddr_t)&handle);
}

char fmt[MAX_COLS] = "";		/* static area where result is built */

/* define what weighted cpu is.  */
#define weighted_cpu(pct, pp) ((pp)->p_time == 0 ? 0.0 : \
			 ((pct) / (1.0 - exp((pp)->p_time * logcpu))))

char *format_next_process(handle, get_userid)

caddr_t handle;
char *(*get_userid)();

{
    register struct proc *pp;
    register long cputime;
    register double pct;
    struct user u;
    struct handle *hp;

    /* find and remember the next proc structure */
    hp = (struct handle *)handle;
    pp = *(hp->next_proc++);
    hp->remaining--;
    

    /* get the process's user struct and set cputime */
    if (getu(pp, &u) == -1)
    {
	(void) strcpy(u.u_comm, "<swapped>");
	cputime = 0;
    }
    else
    {
	/* set u_comm for system processes */
	if (u.u_comm[0] == '\0')
	{
	    if (pp->p_pid == 0)
	    {
		(void) strcpy(u.u_comm, "Swapper");
	    }
	    else if (pp->p_pid == 2)
	    {
		(void) strcpy(u.u_comm, "Pager");
	    }
	}

	cputime = u.u_ru.ru_utime.tv_sec + u.u_ru.ru_stime.tv_sec;
    }

    /* calculate the base for cpu percentages */
    pct = pctdouble(pp->p_pctcpu);

    /* format this entry */
    sprintf(fmt,
	    Proc_format,
	    pp->p_pid,
	    (*get_userid)(pp->p_uid),
	    pp->p_pri - PZERO,
	    pp->p_nice - NZERO,
	    format_k(pagetok(PROCSIZE(pp))),
	    format_k(pagetok(pp->p_rssize)),
	    state_abbrev[pp->p_stat],
	    format_time(cputime),
	    100.0 * weighted_cpu(pct, pp),
	    100.0 * pct,
	    printable(u.u_comm));

    /* return the result */
    return(fmt);
}

/*
 *  getu(p, u) - get the user structure for the process whose proc structure
 *	is pointed to by p.  The user structure is put in the buffer pointed
 *	to by u.  Return 0 if successful, -1 on failure (such as the process
 *	being swapped out).
 */

getu(p, u)

register struct proc *p;
struct user *u;

{
    struct pte uptes[UPAGES];
    register caddr_t upage;
    register struct pte *pte;
    register nbytes, n;

    /*
     *  Check if the process is currently loaded or swapped out.  The way we
     *  get the u area is totally different for the two cases.  For this
     *  application, we just don't bother if the process is swapped out.
     */
    if ((p->p_flag & SLOAD) == 0)
    {
	return(-1);
    }

    /*
     *  Process is currently in memory, we hope!
     */
    if (!getkval((unsigned long)p->p_addr, (int *)uptes, sizeof(uptes),
		"!p->p_addr"))
    {
	/* we can't seem to get to it, so pretend it's swapped out */
	return(-1);
    } 
    upage = (caddr_t)u;
    pte = uptes;
    for (nbytes = sizeof(struct user); nbytes > 0; nbytes -= NBPG)
    {
    	(void) lseek(mem, (long)(pte++->pg_pfnum * NBPG), 0);
	n = MIN(nbytes, NBPG);
	if (read(mem, upage, n) != n)
	{
	    /* we can't seem to get to it, so pretend it's swapped out */
	    return(-1);
	}
	upage += n;
    }
    return(0);
}

/*
 * check_nlist(nlst) - checks the nlist to see if any symbols were not
 *		found.  For every symbol that was not found, a one-line
 *		message is printed to stderr.  The routine returns the
 *		number of symbols NOT found.
 */

int check_nlist(nlst)

register struct nlist *nlst;

{
    register int i;

    /* check to see if we got ALL the symbols we requested */
    /* this will write one line to stderr for every symbol not found */

    i = 0;
    while (nlst->n_name != NULL)
    {
	if (nlst->n_type == 0)
	{
	    /* this one wasn't found */
	    fprintf(stderr, "kernel: no symbol named `%s'\n", nlst->n_name);
	    i = 1;
	}
	nlst++;
    }

    return(i);
}


/*
 *  getkval(offset, ptr, size, refstr) - get a value out of the kernel.
 *	"offset" is the byte offset into the kernel for the desired value,
 *  	"ptr" points to a buffer into which the value is retrieved,
 *  	"size" is the size of the buffer (and the object to retrieve),
 *  	"refstr" is a reference string used when printing error meessages,
 *	    if "refstr" starts with a '!', then a failure on read will not
 *  	    be fatal (this may seem like a silly way to do things, but I
 *  	    really didn't want the overhead of another argument).
 *  	
 */

getkval(offset, ptr, size, refstr)

unsigned long offset;
int *ptr;
int size;
char *refstr;

{
    if (lseek(kmem, (long)offset, 0) == -1)
    {
	if (*refstr == '!')
	{
	    refstr++;
	}
	fprintf(stderr, "%s: lseek to %s: %s\n",
	    KMEM, refstr, sys_errlist[errno]);
	quit(22);
    }
    if (read(kmem, (char *)ptr, size) == -1)
    {
	if (*refstr == '!')
	{
	    /* we lost the race with the kernel, process isn't in memory */
	    return(0);
	} 
	else 
	{
	    fprintf(stderr, "%s: reading %s: %s\n",
		KMEM, refstr, sys_errlist[errno]);
	    quit(23);
	}
    }
    return(1);
}
    
/* comparison routine for qsort */

/*
 *  proc_compare - comparison function for "qsort"
 *	Compares the resource consumption of two processes using five
 *  	distinct keys.  The keys (in descending order of importance) are:
 *  	percent cpu, cpu ticks, state, resident set size, total virtual
 *  	memory usage.  The process states are ordered as follows (from least
 *  	to most important):  WAIT, zombie, sleep, stop, start, run.  The
 *  	array declaration below maps a process state index into a number
 *  	that reflects this ordering.
 */

static unsigned char sorted_state[] =
{
    0,	/* not used		*/
    3,	/* sleep		*/
    1,	/* ABANDONED (WAIT)	*/
    6,	/* run			*/
    5,	/* start		*/
    2,	/* zombie		*/
    4	/* stop			*/
};
 
proc_compare(pp1, pp2)

struct proc **pp1;
struct proc **pp2;

{
    register struct proc *p1;
    register struct proc *p2;
    register int result;
    register pctcpu lresult;

    /* remove one level of indirection */
    p1 = *pp1;
    p2 = *pp2;

    /* compare percent cpu (pctcpu) */
    if ((lresult = p2->p_pctcpu - p1->p_pctcpu) == 0)
    {
	/* use cpticks to break the tie */
	if ((result = p2->p_cpticks - p1->p_cpticks) == 0)
	{
	    /* use process state to break the tie */
	    if ((result = sorted_state[p2->p_stat] -
			  sorted_state[p1->p_stat])  == 0)
	    {
		/* use priority to break the tie */
		if ((result = p2->p_pri - p1->p_pri) == 0)
		{
		    /* use resident set size (rssize) to break the tie */
		    if ((result = p2->p_rssize - p1->p_rssize) == 0)
		    {
			/* use total memory to break the tie */
			result = PROCSIZE(p2) - PROCSIZE(p1);
		    }
		}
	    }
	}
    }
    else
    {
	result = lresult < 0 ? -1 : 1;
    }

    return(result);
}

/*
 * proc_owner(pid) - returns the uid that owns process "pid", or -1 if
 *		the process does not exist.
 *		It is EXTREMLY IMPORTANT that this function work correctly.
 *		If top runs setuid root (as in SVR4), then this function
 *		is the only thing that stands in the way of a serious
 *		security problem.  It validates requests for the "kill"
 *		and "renice" commands.
 */

int proc_owner(pid)

int pid;

{
    register int cnt;
    register struct proc **prefp;
    register struct proc *pp;

    prefp = pref;
    cnt = pref_len;
    while (--cnt >= 0)
    {
	if ((pp = *prefp++)->p_pid == pid)
	{
	    return((int)pp->p_uid);
	}
    }
    return(-1);
}