From 86761c187660d73daed649c6be28502aa5e01a14 Mon Sep 17 00:00:00 2001
Message-Id: <86761c187660d73daed649c6be28502aa5e01a14@dist-git>
From: Martin Kletzander <mkletzan@redhat.com>
Date: Wed, 31 Jan 2018 16:32:13 +0100
Subject: [PATCH] util: Don't output too many zeros from virBitmapToString

https://bugzilla.redhat.com/show_bug.cgi?id=1289368

Truncate the output so that it is only as big as is needed to fit all
the bits, not all the units from the map.  This will be needed in the
future in order to properly format bitmaps for kernel's sysfs files.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
(cherry picked from commit fb106028752d8bd31f48a7c50357b7437b87d7c1)
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 src/qemu/qemu_capabilities.c |  4 ++--
 src/util/virbitmap.c         | 30 ++++++++++++++++++++++++++++--
 src/util/virbitmap.h         |  2 +-
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 5bf188f427..dc546ba702 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1525,7 +1525,7 @@ int virQEMUCapsParseHelpStr(const char *qemu,
                                    qemuCaps, check_yajl) < 0)
         goto cleanup;
 
-    strflags = virBitmapToString(qemuCaps->flags, true);
+    strflags = virBitmapToString(qemuCaps->flags, true, false);
     VIR_DEBUG("Version %u.%u.%u, cooked version %u, flags %s",
               major, minor, micro, *version, NULLSTR(strflags));
     VIR_FREE(strflags);
@@ -2407,7 +2407,7 @@ virQEMUCapsClear(virQEMUCapsPtr qemuCaps,
 
 char *virQEMUCapsFlagsString(virQEMUCapsPtr qemuCaps)
 {
-    return virBitmapToString(qemuCaps->flags, true);
+    return virBitmapToString(qemuCaps->flags, true, false);
 }
 
 
diff --git a/src/util/virbitmap.c b/src/util/virbitmap.c
index f5700a6424..b1c1236fd3 100644
--- a/src/util/virbitmap.c
+++ b/src/util/virbitmap.c
@@ -313,6 +313,7 @@ int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
  * virBitmapToString:
  * @bitmap: Pointer to bitmap
  * @prefix: Whether to prepend "0x"
+ * @trim: Whether to output only the minimum required characters
  *
  * Convert @bitmap to printable string.
  *
@@ -320,10 +321,14 @@ int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
  */
 char *
 virBitmapToString(virBitmapPtr bitmap,
-                  bool prefix)
+                  bool prefix,
+                  bool trim)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     size_t sz;
+    size_t len;
+    size_t diff;
+    char *ret = NULL;
 
     if (prefix)
         virBufferAddLit(&buf, "0x");
@@ -337,7 +342,28 @@ virBitmapToString(virBitmapPtr bitmap,
     }
 
     virBufferCheckError(&buf);
-    return virBufferContentAndReset(&buf);
+    ret = virBufferContentAndReset(&buf);
+    if (!ret)
+        return NULL;
+
+    if (!trim)
+        return ret;
+
+    if (bitmap->max_bit != bitmap->map_len * VIR_BITMAP_BITS_PER_UNIT) {
+        char *tmp = ret;
+
+        if (prefix)
+            tmp += 2;
+
+        len = strlen(tmp);
+        sz = VIR_DIV_UP(bitmap->max_bit, 4);
+        diff = len - sz;
+
+        if (diff)
+            memmove(tmp, tmp + diff, sz + 1);
+    }
+
+    return ret;
 }
 
 /**
diff --git a/src/util/virbitmap.h b/src/util/virbitmap.h
index 720b389cfe..02acb7519d 100644
--- a/src/util/virbitmap.h
+++ b/src/util/virbitmap.h
@@ -80,7 +80,7 @@ bool virBitmapIsBitSet(virBitmapPtr bitmap, size_t b)
 int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(3) ATTRIBUTE_RETURN_CHECK;
 
-char *virBitmapToString(virBitmapPtr bitmap, bool prefix)
+char *virBitmapToString(virBitmapPtr bitmap, bool prefix, bool trim)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
 
 char *virBitmapFormat(virBitmapPtr bitmap);
-- 
2.16.1