#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "../port/error.h" static char Ebadlogctl[] = "unknown log ctl message"; voidlogopen(Log *alog){	lock(alog);	if(waserror()){		unlock(alog);		nexterror();	}	if(alog->opens == 0){		if(alog->nlog == 0)			alog->nlog = 4*1024;		if(alog->minread == 0)			alog->minread = 1;		if(alog->buf == nil)			alog->buf = malloc(alog->nlog);		alog->rptr = alog->buf;		alog->end = alog->buf + alog->nlog;		alog->len = 0;	}	alog->opens++;	unlock(alog);	poperror();} voidlogclose(Log *alog){	lock(alog);	alog->opens--;	if(alog->opens == 0){		free(alog->buf);		alog->buf = nil;	}	unlock(alog);} static intlogready(void *a){	Log *alog = a; 	return alog->len >= alog->minread;} longlogread(Log *alog, void *a, ulong, long n){	int i, d;	char *p, *rptr; 	qlock(&alog->readq);	if(waserror()){		qunlock(&alog->readq);		nexterror();	} 	for(;;){		lock(alog);		if(alog->len >= alog->minread || alog->len >= n){			if(n > alog->len)				n = alog->len;			d = 0;			rptr = alog->rptr;			alog->rptr += n;			if(alog->rptr >= alog->end){				d = alog->rptr - alog->end;				alog->rptr = alog->buf + d;			}			alog->len -= n;			unlock(alog); 			i = n-d;			p = a;			memmove(p, rptr, i);			memmove(p+i, alog->buf, d);			break;		}		else			unlock(alog); 		sleep(&alog->readr, logready, alog);	} 	qunlock(&alog->readq);	poperror(); 	return n;} char*logctl(Log *alog, int argc, char *argv[], Logflag *flags){	int i, set;	Logflag *fp; 	if(argc < 2)		return Ebadlogctl; 	if(strcmp("set", argv[0]) == 0)		set = 1;	else if(strcmp("clear", argv[0]) == 0)		set = 0;	else		return Ebadlogctl; 	for(i = 1; i < argc; i++){		for(fp = flags; fp->name; fp++)			if(strcmp(fp->name, argv[i]) == 0)				break;		if(fp->name == nil)			continue;		if(set)			alog->logmask |= fp->mask;		else			alog->logmask &= ~fp->mask;	} 	return nil;} voidlogn(Log *alog, int mask, void *buf, int n){	char *fp, *t;	int dowake, i; 	if(!(alog->logmask & mask))		return; 	if(alog->opens == 0)		return; 	if(n > alog->nlog)		return; 	lock(alog);	i = alog->len + n - alog->nlog;	if(i > 0){		alog->len -= i;		alog->rptr += i;		if(alog->rptr >= alog->end)			alog->rptr = alog->buf + (alog->rptr - alog->end);	}	t = alog->rptr + alog->len;	fp = buf;	alog->len += n;	while(n-- > 0){		if(t >= alog->end)			t = alog->buf + (t - alog->end);		*t++ = *fp++;	}	dowake = alog->len >= alog->minread;	unlock(alog); 	if(dowake)		wakeup(&alog->readr);} voidlogb(Log *alog, int mask, char *fmt, ...){	int n;	va_list arg;	char buf[128]; 	if(!(alog->logmask & mask))		return; 	if(alog->opens == 0)		return; 	va_start(arg, fmt);	n = vseprint(buf, buf+sizeof(buf), fmt, arg) - buf;	va_end(arg); 	logn(alog, mask, buf, n);}