x_cat.c

来自「TCP-IP红宝书源代码」· C语言 代码 · 共 42 行

/* x_cat.c - x_cat */

#include <conf.h>
#include <kernel.h>

/*------------------------------------------------------------------------
 *  x_cat  -  (command cat) concatenate files and write on stdout
 *------------------------------------------------------------------------
 */
COMMAND	x_cat(stdin, stdout, stderr, nargs, args)
int	stdin, stdout, stderr, nargs;
char	*args[];
{
	int	device;
	char	*buf;
	int	ret;
	int	len;
	int	i;

	if ( (int) (buf = (char *)getmem(512)) == SYSERR) {
		fprintf(stderr, "no memory\n");
		return(SYSERR);
	}
	ret = OK;
	if (nargs == 1) {
		while ( (len=read(stdin, buf, 512)) > 0)
			write(stdout, buf, len);
	}
	for (i=1 ; i<nargs ; i++) {
		if ( (device = open(NAMESPACE,args[i],"ro")) == SYSERR) {
			fprintf(stderr, "Cannot open %s\n", args[i]);
			ret = SYSERR;
			break;
		}
		while ( (len=read(device, buf, 512)) > 0)
			write (stdout, buf, len);
		close(device);
	}
	freemem(buf, 512);
	return(ret);
}