PerlIO_read() can return negative.

p4raw-id: //depot/perl@20048

diff --git a/ext/Digest/MD5/MD5.xs b/ext/Digest/MD5/MD5.xs
index 0bf05f0..5c90f22 100644 (file)
--- a/ext/Digest/MD5/MD5.xs
+++ b/ext/Digest/MD5/MD5.xs
@@ -621,7 +621,7 @@ addfile(self, fh)
        MD5_CTX* context = get_md5_ctx(self);
        STRLEN fill = context->bytes_low & 0x3F;
        unsigned char buffer[4096];
-       int  n;
+       SSize_t n;
     CODE:
        if (fh) {
             if (fill) {
@@ -630,14 +630,19 @@ addfile(self, fh)
                 * first.
                 */
                STRLEN missing = 64 - fill;
-               if ( (n = PerlIO_read(fh, buffer, missing)))
+               n = PerlIO_read(fh, buffer, missing);
+               if (n >= 0)
                    MD5Update(context, buffer, n);
-               else
+               else {
+                   if (PerlIO_error(fh)) {
+                       croak("Reading from filehandle failed");
+                   }
                    XSRETURN(1);  /* self */
+               }
            }
 
            /* Process blocks until EOF or error */
-            while ( (n = PerlIO_read(fh, buffer, sizeof(buffer)))) {
+            while ( (n = PerlIO_read(fh, buffer, sizeof(buffer))) > 0 ) {
                MD5Update(context, buffer, n);
            }