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

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

[Peter A. Bigot]

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
 
@@ -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 {
-- 
2.25.1

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

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1953 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=539937

---Test result---

Test Summary:
CheckPatch                    PASS      0.39 seconds
GitLint                       PASS      0.12 seconds
Prep - Setup ELL              PASS      46.48 seconds
Build - Prep                  PASS      0.15 seconds
Build - Configure             PASS      8.27 seconds
Build - Make                  PASS      207.41 seconds
Make Check                    PASS      9.24 seconds
Make Distcheck                PASS      243.61 seconds
Build w/ext ELL - Configure   PASS      8.39 seconds
Build w/ext ELL - Make        PASS      192.18 seconds

Details
##############################
Test: CheckPatch - PASS
Desc: Run checkpatch.pl script with rule in .checkpatch.conf

##############################
Test: GitLint - PASS
Desc: Run gitlint with rule in .gitlint

##############################
Test: Prep - Setup ELL - PASS
Desc: Clone, build, and install ELL

##############################
Test: Build - Prep - PASS
Desc: Prepare environment for build

##############################
Test: Build - Configure - PASS
Desc: Configure the BlueZ source tree

##############################
Test: Build - Make - PASS
Desc: Build the BlueZ source tree

##############################
Test: Make Check - PASS
Desc: Run 'make check'

##############################
Test: Make Distcheck - PASS
Desc: Run distcheck to check the distribution

##############################
Test: Build w/ext ELL - Configure - PASS
Desc: Configure BlueZ source with '--enable-external-ell' configuration

##############################
Test: Build w/ext ELL - Make - PASS
Desc: Build BlueZ source with '--enable-external-ell' configuration



---
Regards,
Linux Bluetooth

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

[Marcel Holtmann]

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.

Regards

Marcel

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

[Peter A. Bigot]

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

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

[Luiz Augusto von Dentz]

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