diff mbox series

[BlueZ] lib: fix variable-length array declarations in hci structures

Message ID 20210831163545.3646157-1-pab@pabigot.com
State New
Headers show
Series [BlueZ] lib: fix variable-length array declarations in hci structures | expand

Commit Message

Peter A. Bigot Aug. 31, 2021, 4:35 p.m. UTC
Use of zero as the size for arrays as the last element of a structure
is a GNU C extension, which as of GCC 10 produces diagnostics when
values in the extended array are referenced.  Switch to the C99
standard idiom for flexible array members, already in use in a few
other headers.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
---

No changes from previous submission except the BlueZ subject prefix
that I hope will get this into bluez.

 lib/hci.h | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Luiz Augusto von Dentz Sept. 8, 2021, 5:18 p.m. UTC | #1
Hi Marcel,

On Tue, Aug 31, 2021 at 2:54 PM Peter A. Bigot <pab@pabigot.com> wrote:
>

> On 8/31/21 2:23 PM, Marcel Holtmann wrote:

> > Hi Peter,

> >

> >> Use of zero as the size for arrays as the last element of a structure

> >> is a GNU C extension, which as of GCC 10 produces diagnostics when

> >> values in the extended array are referenced.  Switch to the C99

> >> standard idiom for flexible array members, already in use in a few

> >> other headers.

> >>

> >> Signed-off-by: Peter A. Bigot <pab@pabigot.com>

> >> ---

> >>

> >> No changes from previous submission except the BlueZ subject prefix

> >> that I hope will get this into bluez.

> >>

> >> lib/hci.h | 16 ++++++++--------

> >> 1 file changed, 8 insertions(+), 8 deletions(-)

> >>

> >> diff --git a/lib/hci.h b/lib/hci.h

> >> index 3382b87bf..a61568bce 100644

> >> --- a/lib/hci.h

> >> +++ b/lib/hci.h

> >> @@ -729,7 +729,7 @@ typedef struct {

> >> typedef struct {

> >>      uint8_t         flt_type;

> >>      uint8_t         cond_type;

> >> -    uint8_t         condition[0];

> >> +    uint8_t         condition[];

> >> } __attribute__ ((packed)) set_event_flt_cp;

> >> #define SET_EVENT_FLT_CP_SIZE 2

> > does this break any API assumptions? Since as long as libbluetooth exists these headers are API.

>

> The size of the structure remains the same; there should be no API

> changes.  I've done this sort of change multiple times over the years

> and nobody's reported any problems.

>

> Peter


Looks like we also use [] in the kernel so I think it should be safe
to do this change on userspace as well.

-- 
Luiz Augusto von Dentz
diff mbox series

Patch

diff --git a/lib/hci.h b/lib/hci.h
index 3382b87bf..a61568bce 100644
--- a/lib/hci.h
+++ b/lib/hci.h
@@ -729,7 +729,7 @@  typedef struct {
 typedef struct {
 	uint8_t		flt_type;
 	uint8_t		cond_type;
-	uint8_t		condition[0];
+	uint8_t		condition[];
 } __attribute__ ((packed)) set_event_flt_cp;
 #define SET_EVENT_FLT_CP_SIZE 2
 
@@ -2135,7 +2135,7 @@  typedef struct {
 #define EVT_LE_META_EVENT	0x3E
 typedef struct {
 	uint8_t		subevent;
-	uint8_t		data[0];
+	uint8_t		data[];
 } __attribute__ ((packed)) evt_le_meta_event;
 #define EVT_LE_META_EVENT_SIZE 1
 
@@ -2159,7 +2159,7 @@  typedef struct {
 	uint8_t		bdaddr_type;
 	bdaddr_t	bdaddr;
 	uint8_t		length;
-	uint8_t		data[0];
+	uint8_t		data[];
 } __attribute__ ((packed)) le_advertising_info;
 #define LE_ADVERTISING_INFO_SIZE 9
 
@@ -2246,7 +2246,7 @@  typedef struct {
 typedef struct {
 	uint16_t		total_num_blocks;
 	uint8_t			num_handles;
-	cmplt_handle		handles[0];
+	cmplt_handle		handles[];
 }  __attribute__ ((packed)) evt_num_completed_blocks;
 
 #define EVT_AMP_STATUS_CHANGE			0x4D
@@ -2264,7 +2264,7 @@  typedef struct {
 #define EVT_STACK_INTERNAL		0xFD
 typedef struct {
 	uint16_t	type;
-	uint8_t		data[0];
+	uint8_t		data[];
 } __attribute__ ((packed)) evt_stack_internal;
 #define EVT_STACK_INTERNAL_SIZE 2
 
@@ -2407,19 +2407,19 @@  struct hci_dev_req {
 
 struct hci_dev_list_req {
 	uint16_t dev_num;
-	struct hci_dev_req dev_req[0];	/* hci_dev_req structures */
+	struct hci_dev_req dev_req[];	/* hci_dev_req structures */
 };
 
 struct hci_conn_list_req {
 	uint16_t dev_id;
 	uint16_t conn_num;
-	struct hci_conn_info conn_info[0];
+	struct hci_conn_info conn_info[];
 };
 
 struct hci_conn_info_req {
 	bdaddr_t bdaddr;
 	uint8_t  type;
-	struct hci_conn_info conn_info[0];
+	struct hci_conn_info conn_info[];
 };
 
 struct hci_auth_info_req {