src: remove xfree() and use plain free()

xmalloc() (and similar x-functions) are used for allocation. They wrap
malloc()/realloc() but will abort the program on ENOMEM.

The meaning of xmalloc() is that it wraps malloc() but aborts on
failure. I don't think x-functions should have the notion, that this
were potentially a different memory allocator that must be paired
with a particular xfree().

Even if the original intent was that the allocator is abstracted (and
possibly not backed by standard malloc()/free()), then that doesn't seem
a good idea. Nowadays libc allocators are pretty good, and we would need
a very special use cases to switch to something else. In other words,
it will never happen that xmalloc() is not backed by malloc().

Also there were a few places, where a xmalloc() was already "wrongly"
paired with free() (for example, iface_cache_release(), exit_cookie(),
nft_run_cmd_from_buffer()).

Or note how pid2name() returns an allocated string from fscanf(), which
needs to be freed with free() (and not xfree()). This requirement
bubbles up the callers portid2name() and name_by_portid(). This case was
actually handled correctly and the buffer was freed with free(). But it
shows that mixing different allocators is cumbersome to get right.  Of
course, we don't actually have different allocators and whether to use
free() or xfree() makes no different. The point is that xfree() serves
no actual purpose except raising irrelevant questions about whether
x-functions are correctly paired with xfree().

Note that xfree() also used to accept const pointers. It is bad to
unconditionally for all deallocations. Instead prefer to use plain
free(). To free a const pointer use free_const() which obviously wraps
free, as indicated by the name.

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/src/libnftables.c b/src/libnftables.c
index 866b5c6b..ec902009 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -158,7 +158,7 @@ void nft_ctx_clear_vars(struct nft_ctx *ctx)
 		free_const(ctx->vars[i].value);
 	}
 	ctx->num_vars = 0;
-	xfree(ctx->vars);
+	free(ctx->vars);
 }
 
 EXPORT_SYMBOL(nft_ctx_add_include_path);
@@ -182,9 +182,9 @@ EXPORT_SYMBOL(nft_ctx_clear_include_paths);
 void nft_ctx_clear_include_paths(struct nft_ctx *ctx)
 {
 	while (ctx->num_include_paths)
-		xfree(ctx->include_paths[--ctx->num_include_paths]);
+		free(ctx->include_paths[--ctx->num_include_paths]);
 
-	xfree(ctx->include_paths);
+	free(ctx->include_paths);
 	ctx->include_paths = NULL;
 }
 
@@ -343,9 +343,9 @@ void nft_ctx_free(struct nft_ctx *ctx)
 	nft_ctx_clear_vars(ctx);
 	nft_ctx_clear_include_paths(ctx);
 	scope_free(ctx->top_scope);
-	xfree(ctx->state);
+	free(ctx->state);
 	nft_exit(ctx);
-	xfree(ctx);
+	free(ctx);
 }
 
 EXPORT_SYMBOL(nft_ctx_set_output);
@@ -745,7 +745,7 @@ err:
 			if (indesc->name)
 				free_const(indesc->name);
 
-			xfree(indesc);
+			free(indesc);
 		}
 	}
 	free_const(nft->vars_ctx.buf);