Ian Campbell
2011-Sep-21 13:55 UTC
[Xen-devel] [PATCH] libxl: correct allocation size in libxl_list_vm
# HG changeset patch
# User Ian Campbell <ian.campbell@citrix.com>
# Date 1316609964 -3600
# Node ID 4a6d34dffcf9d568a7830ee6de07a581c57e7342
# Parent b11af4a5cdc6a94e41a81d456f07b4d70cdb5ffe
libxl: correct allocation size in libxl_list_vm
*ptr has type libxl_vminfo not libxl_domid, so correct calloc call.
This the second instance of this bug I''ve noticed recently, I did a
quick audit of other similar uses of sizeof(...) and all I spotted
were a couple of harmlessly reversed calloc arguments. It''s a pretty
strong argument for "foo = ..alloc(sizeof(*foo))" rather than
"alloc(sizeof(foos_type))" though...
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
diff -r b11af4a5cdc6 -r 4a6d34dffcf9 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c Wed Sep 21 13:59:24 2011 +0100
+++ b/tools/libxl/libxl.c Wed Sep 21 13:59:24 2011 +0100
@@ -449,7 +449,7 @@ libxl_vminfo * libxl_list_vm(libxl_ctx *
xc_domaininfo_t info[1024];
int size = 1024;
- ptr = calloc(size, sizeof(libxl_dominfo));
+ ptr = calloc(size, sizeof(libxl_vminfo));
if (!ptr)
return NULL;
diff -r b11af4a5cdc6 -r 4a6d34dffcf9 tools/libxl/libxl_dm.c
--- a/tools/libxl/libxl_dm.c Wed Sep 21 13:59:24 2011 +0100
+++ b/tools/libxl/libxl_dm.c Wed Sep 21 13:59:24 2011 +0100
@@ -778,7 +778,7 @@ retry_transaction:
libxl_domain_unpause(ctx, domid);
if (starting_r) {
- *starting_r = calloc(sizeof(libxl__device_model_starting), 1);
+ *starting_r = calloc(1, sizeof(libxl__device_model_starting));
(*starting_r)->domid = info->domid;
(*starting_r)->dom_path = libxl__xs_get_dompath(gc, info->domid);
(*starting_r)->for_spawn = NULL;
@@ -855,11 +855,11 @@ int libxl__create_device_model(libxl__gc
if (starting_r) {
rc = ERROR_NOMEM;
- *starting_r = calloc(sizeof(libxl__device_model_starting), 1);
+ *starting_r = calloc(1, sizeof(libxl__device_model_starting));
if (!*starting_r)
goto out_close;
p = *starting_r;
- p->for_spawn = calloc(sizeof(libxl__spawn_starting), 1);
+ p->for_spawn = calloc(1, sizeof(libxl__spawn_starting));
} else {
p = &buf_starting;
p->for_spawn = NULL;
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Ian Jackson
2011-Sep-28 15:34 UTC
Re: [Xen-devel] [PATCH] libxl: correct allocation size in libxl_list_vm
Ian Campbell writes ("[Xen-devel] [PATCH] libxl: correct allocation size in
libxl_list_vm"):> libxl: correct allocation size in libxl_list_vm
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
> *ptr has type libxl_vminfo not libxl_domid, so correct calloc call.
>
> This the second instance of this bug I''ve noticed recently, I did
a
> quick audit of other similar uses of sizeof(...) and all I spotted
> were a couple of harmlessly reversed calloc arguments. It''s a
pretty
> strong argument for "foo = ..alloc(sizeof(*foo))" rather than
> "alloc(sizeof(foos_type))" though...
The correct approach to this is to make a macro along these lines:
#define OUR_CALLOC(foo) ((foo)=calloc(sizeof(*(foo))))
I think we may have some of these but we should have a complete set.
Ian.
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