1 files changed, 108 insertions, 0 deletions
diff --git a/text_cmds/md5/commoncrypto.c b/text_cmds/md5/commoncrypto.c
new file mode 100644
index 0000000..3551afe
--- /dev/null
+++ b/text_cmds/md5/commoncrypto.c
@@ -0,0 +1,108 @@
+/* Generic CommonDigest wrappers to match the semantics of libmd. */
+
+#include <dispatch/dispatch.h>
+#include <os/assumes.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "commoncrypto.h"
+
+#define CHUNK_SIZE (10 * 1024 * 1024)
+
+char *
+Digest_End(CCDigestRef ctx, char *buf)
+{
+	static const char hex[] = "0123456789abcdef";
+	uint8_t digest[32]; // SHA256 is the biggest
+	size_t i, length;
+
+	(void)os_assumes_zero(CCDigestFinal(ctx, digest));
+	length = CCDigestOutputSize(ctx);
+	os_assert(length <= sizeof(digest));
+	for (i = 0; i < length; i++) {
+		buf[i+i] = hex[digest[i] >> 4];
+		buf[i+i+1] = hex[digest[i] & 0x0f];
+	}
+	buf[i+i] = '\0';
+	return buf;
+}
+
+char *
+Digest_Data(CCDigestAlg algorithm, const void *data, size_t len, char *buf)
+{
+	CCDigestCtx ctx;
+
+	(void)os_assumes_zero(CCDigestInit(algorithm, &ctx));
+	(void)os_assumes_zero(CCDigestUpdate(&ctx, data, len));
+	return Digest_End(&ctx, buf);
+}
+
+char *
+Digest_File(CCDigestAlg algorithm, const char *filename, char *buf)
+{
+	int fd;
+	__block CCDigestCtx ctx;
+	dispatch_queue_t queue;
+	dispatch_semaphore_t sema;
+	dispatch_io_t io;
+	__block int s_error = 0;
+	__block bool eof = false;
+	off_t chunk_offset;
+
+	/* dispatch_io_create_with_path requires an absolute path */
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		return NULL;
+	}
+
+	(void)fcntl(fd, F_NOCACHE, 1);
+
+	(void)os_assumes_zero(CCDigestInit(algorithm, &ctx));
+
+	queue = dispatch_queue_create("com.apple.mtree.io", NULL);
+	os_assert(queue);
+	sema = dispatch_semaphore_create(0);
+	os_assert(sema);
+
+	io = dispatch_io_create(DISPATCH_IO_STREAM, fd, queue, ^(int error) {
+		if (error != 0) {
+			s_error = error;
+		}
+		(void)close(fd);
+		(void)dispatch_semaphore_signal(sema);
+	});
+	os_assert(io);
+	for (chunk_offset = 0; eof == false && s_error == 0; chunk_offset += CHUNK_SIZE) {
+		dispatch_io_read(io, chunk_offset, CHUNK_SIZE, queue, ^(bool done, dispatch_data_t data, int error) {
+			if (data != NULL) {
+				(void)dispatch_data_apply(data, ^(__unused dispatch_data_t region, __unused size_t offset, const void *buffer, size_t size) {
+					(void)os_assumes_zero(CCDigestUpdate(&ctx, buffer, size));
+					return (bool)true;
+				});
+			}
+
+			if (error != 0) {
+				s_error = error;
+			}
+
+			if (done) {
+				eof = (data == dispatch_data_empty);
+				dispatch_semaphore_signal(sema);
+			}
+		});
+		dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
+	}
+	dispatch_release(io); // it will close on its own
+
+	(void)dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
+
+	dispatch_release(queue);
+	dispatch_release(sema);
+
+	if (s_error != 0) {
+		errno = s_error;
+		return NULL;
+	}
+
+	return Digest_End(&ctx, buf);
+}