Miscellaneous 'sendfile' fixes and improved tests.

* libguile/filesys.c (scm_sendfile): In Linux-style sendfile(2) code, if
  EINTR or EAGAIN occurs, set result to 1 (not 0) so that we actually
  keep going.  In non-sendfile(2) code, deal gracefully with short reads
  due to EOF.

* test-suite/tests/filesys.test ("sendfile"): Use 'let*' to guarantee
  the needed order of operations: write (test-file) and then read it.
  Add code to check the written data (not just the returned length) in
  all tests, including the cases that hit EOF prematurely.

2 files changed, 53 insertions, 33 deletions

diff --git a/libguile/filesys.c b/libguile/filesys.c
index d2e565bf8..5f6208d82 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -1160,7 +1160,7 @@ SCM_DEFINE (scm_sendfile, "sendfile", 3, 1, 0,
 	  total += result;
 	else if (result < 0 && (errno == EINTR || errno == EAGAIN))
 	  /* Keep going.  */
-	  result = 0;
+	  result = 1;
       }
     while (total < c_count && result > 0);
   }
@@ -1175,6 +1175,7 @@ SCM_DEFINE (scm_sendfile, "sendfile", 3, 1, 0,
   {
     char buf[8192];
     size_t left;
+    int reached_eof = 0;
 
     if (!SCM_UNBNDP (offset))
       {
@@ -1187,22 +1188,27 @@ SCM_DEFINE (scm_sendfile, "sendfile", 3, 1, 0,
 	  }
       }
 
-    for (total = 0, left = c_count; total < c_count; )
+    for (total = 0, left = c_count; total < c_count && !reached_eof; )
       {
-	size_t asked, obtained;
+	size_t asked, obtained, written;
 
 	asked = SCM_MIN (sizeof buf, left);
 	obtained = full_read (in_fd, buf, asked);
 	if (obtained < asked)
-	  SCM_SYSERROR;
+          {
+            if (errno == 0)
+              reached_eof = 1;
+            else
+              SCM_SYSERROR;
+          }
 
 	left -= obtained;
 
-	obtained = full_write (out_fd, buf, asked);
-	if (obtained < asked)
+	written = full_write (out_fd, buf, obtained);
+	if (written < obtained)
 	  SCM_SYSERROR;
 
-	total += obtained;
+	total += written;
       }
 
   }
diff --git a/test-suite/tests/filesys.test b/test-suite/tests/filesys.test
index 7998bc710..049c9a2b0 100644
--- a/test-suite/tests/filesys.test
+++ b/test-suite/tests/filesys.test
@@ -135,38 +135,52 @@
          (ref  (call-with-input-file file get-bytevector-all)))
 
     (pass-if-equal "file" (cons len ref)
-      (cons (call-with-input-file file
-              (lambda (input)
-                (call-with-output-file (test-file)
-                  (lambda (output)
-                    (sendfile output input len 0)))))
-            (call-with-input-file (test-file) get-bytevector-all)))
+      (let* ((result (call-with-input-file file
+                       (lambda (input)
+                         (call-with-output-file (test-file)
+                           (lambda (output)
+                             (sendfile output input len 0))))))
+             (out (call-with-input-file (test-file) get-bytevector-all)))
+        (cons result out)))
 
     (pass-if-equal "file with offset"
         (cons (- len 777) (call-with-input-file file
                             (lambda (input)
                               (seek input 777 SEEK_SET)
                               (get-bytevector-all input))))
-      (cons (call-with-input-file file
-              (lambda (input)
-                (call-with-output-file (test-file)
-                  (lambda (output)
-                    (sendfile output input (- len 777) 777)))))
-            (call-with-input-file (test-file) get-bytevector-all)))
-
-    (pass-if-equal "file with offset past the end" (- len 777)
-      (call-with-input-file file
-        (lambda (input)
-          (call-with-output-file (test-file)
-            (lambda (output)
-              (sendfile output input len 777))))))
-
-    (pass-if-equal "file with offset near the end" 77
-      (call-with-input-file file
-        (lambda (input)
-          (call-with-output-file (test-file)
-            (lambda (output)
-              (sendfile output input len (- len 77)))))))
+      (let* ((result (call-with-input-file file
+                       (lambda (input)
+                         (call-with-output-file (test-file)
+                           (lambda (output)
+                             (sendfile output input (- len 777) 777))))))
+             (out (call-with-input-file (test-file) get-bytevector-all)))
+        (cons result out)))
+
+    (pass-if-equal "file with offset past the end"
+        (cons (- len 777) (call-with-input-file file
+                            (lambda (input)
+                              (seek input 777 SEEK_SET)
+                              (get-bytevector-all input))))
+      (let* ((result (call-with-input-file file
+                       (lambda (input)
+                         (call-with-output-file (test-file)
+                           (lambda (output)
+                             (sendfile output input len 777))))))
+             (out (call-with-input-file (test-file) get-bytevector-all)))
+        (cons result out)))
+
+    (pass-if-equal "file with offset near the end"
+        (cons 77 (call-with-input-file file
+                   (lambda (input)
+                     (seek input (- len 77) SEEK_SET)
+                     (get-bytevector-all input))))
+      (let* ((result (call-with-input-file file
+                       (lambda (input)
+                         (call-with-output-file (test-file)
+                           (lambda (output)
+                             (sendfile output input len (- len 77)))))))
+             (out (call-with-input-file (test-file) get-bytevector-all)))
+        (cons result out)))
 
     (pass-if-equal "pipe" (cons len ref)
       (if (provided? 'threads)