util: add virFileReadHeaderQuiet wrapper around virFileReadHeaderFD

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/libvirt_private.syms

@@ -1760,6 +1760,7 @@ virFileReadAll;
 virFileReadAllQuiet;
 virFileReadBufQuiet;
 virFileReadHeaderFD;
+virFileReadHeaderQuiet;
 virFileReadLimFD;
 virFileReadLink;
 virFileReadValueBitmap;

src/util/virfile.c

@@ -1367,6 +1367,25 @@ virFileReadHeaderFD(int fd, int maxlen, char **buf)
 }
 
 
+int
+virFileReadHeaderQuiet(const char *path,
+                       int maxlen,
+                       char **buf)
+{
+    int fd;
+    int len;
+
+    fd = open(path, O_RDONLY);
+    if (fd < 0)
+        return -1;
+
+    len = virFileReadHeaderFD(fd, maxlen, buf);
+    VIR_FORCE_CLOSE(fd);
+
+    return len;
+}
+
+
 /* A wrapper around saferead_lim that maps a failure due to
    exceeding the maximum size limitation to EOVERFLOW.  */
 int

src/util/virfile.h

@@ -131,6 +131,8 @@ int virFileDeleteTree(const char *dir);
 
 int virFileReadHeaderFD(int fd, int maxlen, char **buf)
     ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NONNULL(3);
+int virFileReadHeaderQuiet(const char *path, int maxlen, char **buf)
+    ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(3);
 int virFileReadLimFD(int fd, int maxlen, char **buf)
     ATTRIBUTE_RETURN_CHECK ATTRIBUTE_NONNULL(3);
 int virFileReadAll(const char *path, int maxlen, char **buf)