xenpaging: simplify file_op

Catch lseek() errors.
Use -1 as return value and let caller read errno.
Remove const casts from buffer pointers, the page is writeable.
Use wrapper for write() which matches the read() prototype.
Remove unused stdarg.h inclusion.
Remove unused macro.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

diff --git a/tools/xenpaging/file_ops.c b/tools/xenpaging/file_ops.c
index 1032242c6ab4f041c180a7c97fb928239aed79ab..079d2551a87d83978bc497faa8984496d75c2f0c 100644 (file)
--- a/tools/xenpaging/file_ops.c
+++ b/tools/xenpaging/file_ops.c
@@ -21,55 +21,44 @@
 
 
 #include <unistd.h>
-#include <stdarg.h>
 #include <xc_private.h>
 
-
-#define page_offset(_pfn)     (((off_t)(_pfn)) << PAGE_SHIFT)
-
-
 static int file_op(int fd, void *page, int i,
-                   ssize_t (*fn)(int, const void *, size_t))
+                   ssize_t (*fn)(int, void *, size_t))
 {
     off_t seek_ret;
-    int total;
+    int total = 0;
     int bytes;
-    int ret;
 
     seek_ret = lseek(fd, i << PAGE_SHIFT, SEEK_SET);
+    if ( seek_ret == (off_t)-1 )
+        return -1;
 
-    total = 0;
     while ( total < PAGE_SIZE )
     {
         bytes = fn(fd, page + total, PAGE_SIZE - total);
         if ( bytes <= 0 )
-        {
-            ret = -errno;
-            goto err;
-        }
+            return -1;
 
         total += bytes;
     }
 
     return 0;
-
- err:
-    return ret;
 }
 
-static ssize_t my_read(int fd, const void *buf, size_t count)
+static ssize_t my_write(int fd, void *buf, size_t count)
 {
-    return read(fd, (void *)buf, count);
+    return write(fd, buf, count);
 }
 
 int read_page(int fd, void *page, int i)
 {
-    return file_op(fd, page, i, &my_read);
+    return file_op(fd, page, i, &read);
 }
 
 int write_page(int fd, void *page, int i)
 {
-    return file_op(fd, page, i, &write);
+    return file_op(fd, page, i, &my_write);
 }