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)

2 files changed, 20 insertions, 7 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;
 }
diff --git a/source4/lib/talloc.c b/source4/lib/talloc.c
index 3e42fc68f8..c08495aae4 100644
--- a/source4/lib/talloc.c
+++ b/source4/lib/talloc.c
@@ -26,6 +26,9 @@
 
 #include "includes.h"
 
+#undef talloc
+#define talloc(ctx, size) _talloc(ctx, size)
+
 #define MAX_TALLOC_SIZE 0x10000000
 #define TALLOC_MAGIC 0xe814ec4f
 #define TALLOC_MAGIC_FREE 0x7faebef3
@@ -59,7 +62,7 @@ static struct talloc_chunk *talloc_chunk_from_ptr(void *ptr)
 /* 
    Allocate a bit of memory as a child of an existing pointer
 */
-void *talloc(void *context, size_t size)
+void *_talloc(void *context, size_t size)
 {
 	struct talloc_chunk *tc;
 
@@ -289,7 +292,7 @@ int talloc_free(void *ptr)
 /*
   A talloc version of realloc 
 */
-void *talloc_realloc(void *ptr, size_t size)
+void *_talloc_realloc(void *ptr, size_t size, const char *name)
 {
 	struct talloc_chunk *tc;
 	void *new_ptr;
@@ -302,7 +305,7 @@ void *talloc_realloc(void *ptr, size_t size)
 
 	/* realloc(NULL) is equavalent to malloc() */
 	if (ptr == NULL) {
-		return talloc(NULL, size);
+		return talloc_named_const(NULL, size, name);
 	}
 
 	tc = talloc_chunk_from_ptr(ptr);
@@ -330,6 +333,7 @@ void *talloc_realloc(void *ptr, size_t size)
 	}
 
 	tc->size = size;
+	talloc_set_name_const(tc+1, name);
 
 	return (void *)(tc+1);
 }
@@ -582,26 +586,30 @@ char *talloc_asprintf_append(char *s,
 /*
   alloc an array, checking for integer overflow in the array size
 */
-void *talloc_array(void *ctx, size_t el_size, uint_t count)
+void *talloc_array(void *ctx, size_t el_size, uint_t count, const char *name)
 {
 	if (count == 0 ||
 	    count >= MAX_TALLOC_SIZE/el_size) {
 		return NULL;
 	}
-	return talloc(ctx, el_size * count);
+	return talloc_named_const(ctx, el_size * count, name);
 }
 
 
 /*
   realloc an array, checking for integer overflow in the array size
 */
-void *talloc_realloc_array(void *ptr, size_t el_size, uint_t count)
+void *talloc_realloc_array(void *ptr, size_t el_size, uint_t count, const char *name)
 {
 	if (count == 0 ||
 	    count >= MAX_TALLOC_SIZE/el_size) {
 		return NULL;
 	}
-	return talloc_realloc(ptr, el_size * count);
+	ptr = talloc_realloc(ptr, el_size * count);
+	if (ptr) {
+		talloc_set_name_const(ptr, name);
+	}
+	return ptr;
 }
 
 /*