open.c

Linux 1.0 内核C源代码 Linux最早版本代码 由Linus Torvalds亲自书写的

/*
 *  linux/lib/open.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#define __LIBRARY__
#include <linux/unistd.h>
#include <stdarg.h>

int open(const char * filename, int flag, ...)
{
	register int res;
	va_list arg;

	va_start(arg,flag);
	__asm__("movl %2,%%ebx\n\t"
		"int $0x80"
		:"=a" (res)
		:"0" (__NR_open),"g" ((long)(filename)),"c" (flag),
		"d" (va_arg(arg,int)));
	if (res>=0)
		return res;
	errno = -res;
	return -1;
}