/* * sha1sum - compute SHA1 or SHA2 digest */#include <u.h>#include <libc.h>#include <bio.h>#include <libsec.h> #pragma	varargck	type	"M"	uchar* typedef struct Sha2 Sha2;struct Sha2 {	int	bits;	int	dlen;	DigestState* (*func)(uchar *, ulong, uchar *, DigestState *);}; static Sha2 sha2s[] = {	224,	SHA2_224dlen,	sha2_224,	256,	SHA2_256dlen,	sha2_256,	384,	SHA2_384dlen,	sha2_384,	512,	SHA2_512dlen,	sha2_512,}; static DigestState* (*shafunc)(uchar *, ulong, uchar *, DigestState *);static int shadlen; static intdigestfmt(Fmt *fmt){	char buf[SHA2_512dlen*2 + 1];	uchar *p;	int i; 	p = va_arg(fmt->args, uchar*);	for(i = 0; i < shadlen; i++)		sprint(buf + 2*i, "%.2ux", p[i]);	return fmtstrcpy(fmt, buf);} static voidsum(int fd, char *name){	int n;	uchar buf[8192], digest[SHA2_512dlen];	DigestState *s; 	s = (*shafunc)(nil, 0, nil, nil);	while((n = read(fd, buf, sizeof buf)) > 0)		(*shafunc)(buf, n, nil, s);	if(n < 0){		fprint(2, "reading %s: %r\n", name? name: "stdin");		return;	}	(*shafunc)(nil, 0, digest, s);	if(name == nil)		print("%M\n", digest);	else		print("%M\t%s\n", digest, name);} static voidusage(void){	fprint(2, "usage: %s [-2 bits] [file...]\n", argv0);	exits("usage");} voidmain(int argc, char *argv[]){	int i, fd, bits;	Sha2 *sha; 	shafunc = sha1;	shadlen = SHA1dlen;	ARGBEGIN{	case '2':		bits = atoi(EARGF(usage()));		for (sha = sha2s; sha < sha2s + nelem(sha2s); sha++)			if (sha->bits == bits)				break;		if (sha >= sha2s + nelem(sha2s))			sysfatal("unknown number of sha2 bits: %d", bits);		shafunc = sha->func;		shadlen = sha->dlen;		break;	default:		usage();	}ARGEND 	fmtinstall('M', digestfmt); 	if(argc == 0)		sum(0, nil);	else		for(i = 0; i < argc; i++){			fd = open(argv[i], OREAD);			if(fd < 0){				fprint(2, "%s: can't open %s: %r\n", argv0, argv[i]);				continue;			}			sum(fd, argv[i]);			close(fd);		}	exits(nil);}