devcons.c

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"../port/error.h"

void	(*consdebug)(void) = nil;

Queue*	kbdq;			/* unprocessed console input */
Queue*	lineq;			/* processed console input */
Queue*	printq;			/* console output */

static struct
{
	QLock;

	int	raw;		/* true if we shouldn't process input */
	int	ctl;		/* number of opens to the control file */
	int	x;		/* index into line */
	char	line[1024];	/* current input line */

	Rune	c;
	int	count;
	int	repeat;
	int	ctlpoff;
} kbd;

char	sysname[NAMELEN];
vlong	fasthz;

static ulong	randomread(void*, ulong);
static void	randominit(void);
static void	seedrand(void);
static int	readtime(ulong, char*, int);
static int	readbintime(char*, int);
static int	writetime(char*, int);
static int	writebintime(char*, int);

void
printinit(void)
{
	lineq = qopen(2*1024, 0, 0, 0);
	if(lineq == nil)
		panic("printinit");
	qnoblock(lineq, 1);
}

int
consactive(void)
{
	if(printq)
		return qlen(printq) > 0;
	return 0;
}

void
prflush(void)
{
	while(consactive())
		;
}

/*
 *   Print a string on the console.  Convert \n to \r\n for serial
 *   line consoles.  Locking of the queues is left up to the screen
 *   or uart code.  Multi-line messages to serial consoles may get
 *   interspersed with other messages.
 */
static void
putstrn0(char *str, int n, int usewrite)
{
	int m;
	char *t;
	char buf[PRINTSIZE+2];

	/*
	 *  if there's an attached bit mapped display,
	 *  put the message there.  screenputs is defined
	 *  as a null macro for systems that have no such
	 *  display.
	 */
	screenputs(str, n);

	/*
	 *  if there's a serial line being used as a console,
	 *  put the message there.
	 */
	if(printq == 0)
		return;

	while(n > 0) {
		t = memchr(str, '\n', n);
		if(t) {
			m = t - str;
			memmove(buf, str, m);
			buf[m] = '\r';
			buf[m+1] = '\n';
			if(usewrite)
				qwrite(printq, buf, m+2);
			else
				qiwrite(printq, buf, m+2);
			str = t + 1;
			n -= m + 1;
		} else {
			if(usewrite)
				qwrite(printq, str, n);
			else
				qiwrite(printq, str, n);
			break;
		}
	}
}

void
putstrn(char *str, int n)
{
	putstrn0(str, n, 0);
}

int
snprint(char *s, int n, char *fmt, ...)
{
	va_list arg;

	va_start(arg, fmt);
	n = doprint(s, s+n, fmt, arg) - s;
	va_end(arg);
	return n;
}

int
sprint(char *s, char *fmt, ...)
{
	int n;
	va_list arg;

	va_start(arg, fmt);
	n = doprint(s, s+PRINTSIZE, fmt, arg) - s;
	va_end(arg);
	return n;
}

int noprint;

int
print(char *fmt, ...)
{
	int n;
	va_list arg;
	char buf[PRINTSIZE];

	if(noprint)
		return -1;

	va_start(arg, fmt);
	n = doprint(buf, buf+sizeof(buf), fmt, arg) - buf;
	va_end(arg);
	putstrn(buf, n);

	return n;
}

int
iprint(char *fmt, ...)
{
	int n, s;
	va_list arg;
	char buf[PRINTSIZE];

	s = splhi();
	va_start(arg, fmt);
	n = doprint(buf, buf+sizeof(buf), fmt, arg) - buf;
	va_end(arg);
	serialputs(buf, n);
//	screenputs(buf, n);
	splx(s);

	return n;
}

void
panic(char *fmt, ...)
{
	int n;
	va_list arg;
	char buf[PRINTSIZE];

	splhi();
	strcpy(buf, "panic: ");
	va_start(arg, fmt);
	n = doprint(buf+strlen(buf), buf+sizeof(buf), fmt, arg) - buf;
	va_end(arg);
	buf[n] = '\n';
	serialputs(buf, n+1);
	if(consdebug)
		consdebug();
	putstrn(buf, n+1);
	spllo();
	prflush();
	dumpstack();

	exit(1);
}

void
_assert(char *fmt)
{
	panic("assert failed: %s", fmt);
}

int
pprint(char *fmt, ...)
{
	int n;
	Chan *c;
	va_list arg;
	char buf[2*PRINTSIZE];

	if(up == nil || up->fgrp == nil)
		return 0;

	c = up->fgrp->fd[2];
	if(c==0 || (c->mode!=OWRITE && c->mode!=ORDWR))
		return 0;
	n = sprint(buf, "%s %lud: ", up->text, up->pid);
	va_start(arg, fmt);
	n = doprint(buf+n, buf+sizeof(buf), fmt, arg) - buf;
	va_end(arg);

	if(waserror())
		return 0;
	devtab[c->type]->write(c, buf, n, c->offset);
	poperror();

	lock(c);
	c->offset += n;
	unlock(c);

	return n;
}

void
echo(Rune r, char *buf, int n)
{
	static int ctrlt, pid;
	extern ulong etext;
	int x;

	/*
	 * ^p hack
	 */
	if(r==0x10 && cpuserver && !kbd.ctlpoff){
		lock(&active);
		active.exiting = 1;
		unlock(&active);
	}

	/*
	 * ^t hack BUG
	 */
	if(ctrlt == 2){
		ctrlt = 0;
		switch(r){
		case 0x14:
			break;	/* pass it on */
		case 's':
			dumpstack();
			break;
		case 'x':
			xsummary();
			ixsummary();
			mallocsummary();
			pagersummary();
			break;
		case 'd':
			if(consdebug == nil)
				consdebug = rdb;
			else
				consdebug = nil;
			print("consdebug now 0x%p\n", consdebug);
			return;
		case 'D':
			if(consdebug == nil)
				consdebug = rdb;
			consdebug();
			return;
		case 'p':
			x = spllo();
			procdump();
			splx(x);
			return;
		case 'q':
			scheddump();
			break;
		case 'k':
			if(!cpuserver)
				killbig();
			break;
		case 'r':
			exit(0);
			break;
		}
	}
	else if(r == 0x14){
		ctrlt++;
		return;
	}
	ctrlt = 0;
	if(kbd.raw)
		return;

	/*
	 *  finally, the actual echoing
	 */
	if(r == '\n'){
		if(printq)
			qiwrite(printq, "\r", 1);
	} else if(r == 0x15){
		buf = "^U\n";
		n = 3;
	}
	screenputs(buf, n);
	if(printq)
		qiwrite(printq, buf, n);
}

/*
 *  Called by a uart interrupt for console input.
 *
 *  turn '\r' into '\n' before putting it into the queue.
 */
int
kbdcr2nl(Queue *q, int ch)
{
	if(ch == '\r')
		ch = '\n';
	return kbdputc(q, ch);
}

/*
 *  Put character, possibly a rune, into read queue at interrupt time.
 *  Called at interrupt time to process a character.
 */
int
kbdputc(Queue*, int ch)
{
	int n;
	char buf[3];
	Rune r;

	r = ch;
	n = runetochar(buf, &r);
	if(n == 0)
		return 0;
	echo(r, buf, n);
	kbd.c = r;
	qproduce(kbdq, buf, n);
	return 0;
}

void
kbdrepeat(int rep)
{
	kbd.repeat = rep;
	kbd.count = 0;
}

void
kbdclock(void)
{
	if(kbd.repeat == 0)
		return;
	if(kbd.repeat==1 && ++kbd.count>HZ){
		kbd.repeat = 2;
		kbd.count = 0;
		return;
	}
	if(++kbd.count&1)
		kbdputc(kbdq, kbd.c);
}

enum{
	Qdir,
	Qauth,
	Qauthcheck,
	Qauthent,
	Qbintime,
	Qcons,
	Qconsctl,
	Qcputime,
	Qdrivers,
	Qkey,
	Qhostdomain,
	Qhostowner,
	Qnull,
	Qpgrpid,
	Qpid,
	Qppid,
	Qrandom,
	Qreboot,
	Qswap,
	Qsysname,
	Qsysstat,
	Qtime,
	Quser,
	Qzero,
};

enum
{
	VLNUMSIZE=	22,
};

static Dirtab consdir[]={
	"authenticate",	{Qauth},	0,		0666,
	"authcheck",	{Qauthcheck},	0,		0666,
	"authenticator", {Qauthent},	0,		0666,
	"bintime",	{Qbintime},	24,		0664,
	"cons",		{Qcons},	0,		0660,
	"consctl",	{Qconsctl},	0,		0220,
	"cputime",	{Qcputime},	6*NUMSIZE,	0444,
	"drivers",	{Qdrivers},	0,		0644,
	"hostdomain",	{Qhostdomain},	DOMLEN,		0664,
	"hostowner",	{Qhostowner},	NAMELEN,	0664,
	"key",		{Qkey},		DESKEYLEN,	0622,
	"null",		{Qnull},	0,		0666,
	"pgrpid",	{Qpgrpid},	NUMSIZE,	0444,
	"pid",		{Qpid},		NUMSIZE,	0444,
	"ppid",		{Qppid},	NUMSIZE,	0444,
	"random",	{Qrandom},	0,		0664,
	"reboot",	{Qreboot},	0,		0664,
	"swap",		{Qswap},	0,		0664,
	"sysname",	{Qsysname},	0,		0664,
	"sysstat",	{Qsysstat},	0,		0666,
	"time",		{Qtime},	NUMSIZE+3*VLNUMSIZE,	0664,
	"user",		{Quser},	NAMELEN,	0666,
	"zero",		{Qzero},	0,		0444,
};

int
readnum(ulong off, char *buf, ulong n, ulong val, int size)
{
	char tmp[64];

	snprint(tmp, sizeof(tmp), "%*.0lud", size-1, val);
	tmp[size-1] = ' ';
	if(off >= size)
		return 0;
	if(off+n > size)
		n = size-off;
	memmove(buf, tmp+off, n);
	return n;
}

int
readstr(ulong off, char *buf, ulong n, char *str)
{
	int size;

	size = strlen(str);
	if(off >= size)
		return 0;
	if(off+n > size)
		n = size-off;
	memmove(buf, str+off, n);
	return n;
}

static void
consinit(void)
{
	todinit();
	randominit();
}

static Chan*
consattach(char *spec)
{
	return devattach('c', spec);
}

static int
conswalk(Chan *c, char *name)
{
	return devwalk(c, name, consdir, nelem(consdir), devgen);
}

static void
consstat(Chan *c, char *dp)
{
	devstat(c, dp, consdir, nelem(consdir), devgen);
}

static Chan*
consopen(Chan *c, int omode)
{
	c->aux = 0;
	switch(c->qid.path){
	case Qconsctl:
		if(!iseve())
			error(Eperm);
		qlock(&kbd);
		kbd.ctl++;
		qunlock(&kbd);
		break;
	}
	return devopen(c, omode, consdir, nelem(consdir), devgen);
}

static void
consclose(Chan *c)
{
	/* last close of control file turns off raw */
	switch(c->qid.path){
	case Qconsctl:
		if(c->flag&COPEN){
			qlock(&kbd);
			if(--kbd.ctl == 0)
				kbd.raw = 0;
			qunlock(&kbd);
		}
		break;
	case Qauth:
	case Qauthcheck:
	case Qauthent:
		authclose(c);
	}
}

static long
consread(Chan *c, void *buf, long n, vlong off)
{
	ulong l;
	Mach *mp;
	char *b, *bp;
	char tmp[128];		/* must be >= 6*NUMSIZE */
	char *cbuf = buf;
	int ch, i, k, id, eol;
	vlong offset = off;

	if(n <= 0)
		return n;
	switch(c->qid.path & ~CHDIR){
	case Qdir:
		return devdirread(c, buf, n, consdir, nelem(consdir), devgen);

	case Qcons:
		qlock(&kbd);
		if(waserror()) {
			qunlock(&kbd);
			nexterror();
		}
		if(kbd.raw) {
			if(qcanread(lineq))
				n = qread(lineq, buf, n);
			else {
				/* read as much as possible */
				do {
					i = qread(kbdq, cbuf, n);
					cbuf += i;
					n -= i;
				} while (n>0 && qcanread(kbdq));
				n = cbuf - (char*)buf;
			}
		} else {
			while(!qcanread(lineq)) {
				qread(kbdq, &kbd.line[kbd.x], 1);
				ch = kbd.line[kbd.x];
				if(kbd.raw){
					qiwrite(lineq, kbd.line, kbd.x+1);
					kbd.x = 0;
					continue;
				}
				eol = 0;
				switch(ch){
				case '\b':
					if(kbd.x)
						kbd.x--;
					break;
				case 0x15:
					kbd.x = 0;
					break;
				case '\n':
				case 0x04:
					eol = 1;
				default:
					kbd.line[kbd.x++] = ch;
					break;
				}
				if(kbd.x == sizeof(kbd.line) || eol){
					if(ch == 0x04)
						kbd.x--;
					qwrite(lineq, kbd.line, kbd.x);
					kbd.x = 0;
				}
			}
			n = qread(lineq, buf, n);
		}
		qunlock(&kbd);
		poperror();
		return n;

	case Qcputime:
		k = offset;
		if(k >= 6*NUMSIZE)
			return 0;
		if(k+n > 6*NUMSIZE)
			n = 6*NUMSIZE - k;
		/* easiest to format in a separate buffer and copy out */
		for(i=0; i<6 && NUMSIZE*i<k+n; i++){
			l = up->time[i];
			if(i == TReal)
				l = MACHP(0)->ticks - l;
			l = TK2MS(l);
			readnum(0, tmp+NUMSIZE*i, NUMSIZE, l, NUMSIZE);
		}
		memmove(buf, tmp+k, n);
		return n;

	case Qpgrpid: