Index: head/lib/libmd/mdXhl.c
===================================================================
--- head/lib/libmd/mdXhl.c	(revision 294036)
+++ head/lib/libmd/mdXhl.c	(revision 294037)
@@ -1,118 +1,120 @@
-/* mdXhl.c * ----------------------------------------------------------------------------
+/* mdXhl.c
+ * ----------------------------------------------------------------------------
  * "THE BEER-WARE LICENSE" (Revision 42):
  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
  * can do whatever you want with this stuff. If we meet some day, and you think
  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  * ----------------------------------------------------------------------------
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
 
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "mdX.h"
 
 char *
 MDXEnd(MDX_CTX *ctx, char *buf)
 {
 	int i;
 	unsigned char digest[LENGTH];
 	static const char hex[]="0123456789abcdef";
 
 	if (!buf)
 		buf = malloc(2*LENGTH + 1);
 	if (!buf)
 		return 0;
 	MDXFinal(digest, ctx);
 	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 *
 MDXFile(const char *filename, char *buf)
 {
 	return (MDXFileChunk(filename, buf, 0, 0));
 }
 
 char *
 MDXFileChunk(const char *filename, char *buf, off_t ofs, off_t len)
 {
 	unsigned char buffer[16*1024];
 	MDX_CTX ctx;
 	struct stat stbuf;
-	int f, i, e;
-	off_t n;
+	int fd, readrv, e;
+	off_t remain;
 
+	if (len < 0) {
+		errno = EINVAL;
+		return NULL;
+	}
+
 	MDXInit(&ctx);
-	f = open(filename, O_RDONLY);
-	if (f < 0)
-		return 0;
-	if (fstat(f, &stbuf) < 0) {
-		i = -1;
-		goto error;
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+	if (ofs != 0) {
+		errno = 0;
+		if (lseek(fd, ofs, SEEK_SET) != ofs ||
+		    (ofs == -1 && errno != 0)) {
+			readrv = -1;
+			goto error;
+		}
 	}
-	if (ofs > stbuf.st_size)
-		ofs = stbuf.st_size;
-	if ((len == 0) || (len > stbuf.st_size - ofs))
-		len = stbuf.st_size - ofs;
-	if (lseek(f, ofs, SEEK_SET) < 0) {
-		i = -1;
-		goto error;
-	}
-	n = len;
-	i = 0;
-	while (n > 0) {
-		if (n > sizeof(buffer))
-			i = read(f, buffer, sizeof(buffer));
+	remain = len;
+	readrv = 0;
+	while (len == 0 || remain > 0) {
+		if (len == 0 || remain > sizeof(buffer))
+			readrv = read(fd, buffer, sizeof(buffer));
 		else
-			i = read(f, buffer, n);
-		if (i <= 0) 
+			readrv = read(fd, buffer, remain);
+		if (readrv <= 0) 
 			break;
-		MDXUpdate(&ctx, buffer, i);
-		n -= i;
+		MDXUpdate(&ctx, buffer, readrv);
+		remain -= readrv;
 	} 
 error:
 	e = errno;
-	close(f);
+	close(fd);
 	errno = e;
-	if (i < 0)
-		return 0;
+	if (readrv < 0)
+		return NULL;
 	return (MDXEnd(&ctx, buf));
 }
 
 char *
 MDXData (const void *data, unsigned int len, char *buf)
 {
 	MDX_CTX ctx;
 
 	MDXInit(&ctx);
 	MDXUpdate(&ctx,data,len);
 	return (MDXEnd(&ctx, buf));
 }
 
 #ifdef WEAK_REFS
 /* When building libmd, provide weak references. Note: this is not
    activated in the context of compiling these sources for internal
    use in libcrypt.
  */
 #undef MDXEnd
 __weak_reference(_libmd_MDXEnd, MDXEnd);
 #undef MDXFile
 __weak_reference(_libmd_MDXFile, MDXFile);
 #undef MDXFileChunk
 __weak_reference(_libmd_MDXFileChunk, MDXFileChunk);
 #undef MDXData
 __weak_reference(_libmd_MDXData, MDXData);
 #endif