#include <u.h>#include <libc.h>#include <bio.h>#include <mp.h>#include <libsec.h> voidusage(void){	fprint(2, "auth/pemdecode section [file]\n");	exits("usage");} voidmain(int argc, char **argv){	char *buf;	uchar *bin;	int fd;	long n, tot;	int len;	char *tag, *file; 	ARGBEGIN{	default:		usage();	}ARGEND 	if(argc != 1 && argc != 2)		usage(); 	tag = argv[0];	if(argc == 2)		file = argv[1];	else		file = "/dev/stdin"; 	if((fd = open(file, OREAD)) < 0)		sysfatal("open %s: %r", file);	buf = nil;	tot = 0;	for(;;){		buf = realloc(buf, tot+8192);		if(buf == nil)			sysfatal("realloc: %r");		if((n = read(fd, buf+tot, 8192)) < 0)			sysfatal("read: %r");		if(n == 0)			break;		tot += n;	}	buf[tot] = 0;	bin = decodepem(buf, tag, &len, nil);	if(bin == nil)		sysfatal("cannot extract section '%s' from pem", tag);	if((n=write(1, bin, len)) != len)		sysfatal("writing %d bytes got %ld: %r", len, n);	exits(0);}