#include <u.h>#include <libc.h> char	buf[8192];#define	NARG	5int	arg[NARG]; int	sysr1(void); struct{	char	*name;	int	(*func)(...);}tab[]={#include "tab.h"	0,		0}; voidmain(int argc, char *argv[]){	int i, r;	int oflag=0;	int parse(char *);	char ebuf[ERRLEN]; 	ARGBEGIN{	case 'o':		oflag++;		break;	default:		goto Usage;	}ARGEND	if(argc<1 || argc>1+NARG){    Usage:		fprint(2, "usage: syscall [-o] entry [args; buf==1024 byte buffer]\n");		fprint(2, "\tsyscall write 1 hello 5\n");		fprint(2, "\tsyscall -o errstr buf\n");		exits("usage");	}	for(i=1; i<argc; i++)		arg[i-1]=parse(argv[i]);	for(i=0; tab[i].name; i++)		if(strcmp(tab[i].name, argv[0])==0){			/* special case for seek; vlongs are problematic */			if(strcmp(argv[0], "seek") == 0)				r=seek(arg[0], arg[1], arg[2]);			else				r=(*tab[i].func)(arg[0], arg[1], arg[2], arg[3], arg[4]);			if(r == -1){				errstr(ebuf);				fprint(2, "syscall: return %d, error:%s\n", r, ebuf);			}else{				ebuf[0] = 0;				fprint(2, "syscall: return %d, no error\n", r);			}			if(oflag)				print("%s\n", buf);			exits(ebuf);		}	fprint(2, "syscall: %s not known\n", argv[0]);	exits("unknown");}intparse(char *s){	char *t;	long l; 	if(strcmp(s, "buf") == 0)		return (int)buf;	l = strtoul(s, &t, 0);	if(t>s && *t==0)		return l;	return (int)s; }