From fb106028752d8bd31f48a7c50357b7437b87d7c1 Mon Sep 17 00:00:00 2001
From: Martin Kletzander <mkletzan@redhat.com>
Date: Wed, 23 Aug 2017 09:09:17 +0200
Subject: [PATCH] util: Don't output too many zeros from virBitmapToString

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>
---
 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 e318eac557..554c8dffee 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1510,7 +1510,7 @@ 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);
@@ -2377,7 +2377,7 @@ 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);
-- 
GitLab