r2649: - used some cpp tricks to make users of talloc() and talloc_realloc()

  to get auto-naming of pointers very cheaply.

- fixed a couple of memory leaks found with the new tricks

A typical exit report for smbd is now:

talloc report on 'null_context' (total 811 bytes in 54 blocks)
        auth/auth_sam.c:334            contains     20 bytes in   1 blocks
        struct auth_serversupplied_info contains    498 bytes in  33 blocks
        UNNAMED                        contains      8 bytes in   1 blocks
        lib/data_blob.c:40             contains     16 bytes in   1 blocks
        iconv(CP850,UTF8)              contains     61 bytes in   4 blocks
        iconv(UTF8,CP850)              contains     61 bytes in   4 blocks
        iconv(UTF8,UTF-16LE)           contains     67 bytes in   4 blocks
        iconv(UTF-16LE,UTF8)           contains     67 bytes in   4 blocks
        UNNAMED                        contains     13 bytes in   1 blocks

which is much better than before
(This used to be commit 6e721393d03afd3c2f8ced8422533547a9e33342)

1 files changed, 5 insertions, 0 deletions

diff --git a/source4/lib/data_blob.c b/source4/lib/data_blob.c
index e10ebfe606..c8c57849d2 100644
--- a/source4/lib/data_blob.c
+++ b/source4/lib/data_blob.c
@@ -56,6 +56,11 @@ DATA_BLOB data_blob_talloc(TALLOC_CTX *mem_ctx, const void *p, size_t length)
 
 	if (ret.data) {
 		ret.data = talloc_steal(mem_ctx, ret.data);
+	} else {
+		/* this ensures the blob has the context attached, so a zero length call
+		   to data_blob_talloc followed by a realloc doesn't cause the memory to come
+		   from the NULL context */
+		ret.data = talloc(mem_ctx, 0);
 	}
 	return ret;
 }