* [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
@ 2020-08-20 16:05 Zhao Heming
2020-08-20 16:08 ` heming.zhao
2020-08-26 5:18 ` heming.zhao
0 siblings, 2 replies; 7+ messages in thread
From: Zhao Heming @ 2020-08-20 16:05 UTC (permalink / raw)
To: linux-lvm; +Cc: mcsontos, Zhao Heming
this patch makes gcc happy with compiling option: [-Wstringop-overflow=]
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
---
device_mapper/libdm-common.c | 2 +-
lib/activate/fs.c | 2 +-
libdm/libdm-common.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c
index bc691d6..3627457 100644
--- a/device_mapper/libdm-common.c
+++ b/device_mapper/libdm-common.c
@@ -1445,7 +1445,7 @@ struct node_op_parms {
char *old_name;
int warn_if_udev_failed;
unsigned rely_on_udev;
- char names[0];
+ char names[];
};
static void _store_str(char **pos, char **ptr, const char *str)
diff --git a/lib/activate/fs.c b/lib/activate/fs.c
index b2c99fc..96f7df6 100644
--- a/lib/activate/fs.c
+++ b/lib/activate/fs.c
@@ -313,7 +313,7 @@ struct fs_op_parms {
char *lv_name;
char *dev;
char *old_lv_name;
- char names[0];
+ char names[];
};
static void _store_str(char **pos, char **ptr, const char *str)
diff --git a/libdm/libdm-common.c b/libdm/libdm-common.c
index d75c704..d587c32 100644
--- a/libdm/libdm-common.c
+++ b/libdm/libdm-common.c
@@ -1443,7 +1443,7 @@ struct node_op_parms {
char *old_name;
int warn_if_udev_failed;
unsigned rely_on_udev;
- char names[0];
+ char names[];
};
static void _store_str(char **pos, char **ptr, const char *str)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-08-20 16:05 [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array Zhao Heming
@ 2020-08-20 16:08 ` heming.zhao
2020-08-26 5:18 ` heming.zhao
1 sibling, 0 replies; 7+ messages in thread
From: heming.zhao @ 2020-08-20 16:08 UTC (permalink / raw)
To: linux-lvm; +Cc: mcsontos
more info or discussion with this patch.
I met this compiling issue when I was creating openSUSE package.
I'm a little confused & wonder why Fedora can pass this gcc warning.
On 8/21/20 12:05 AM, Zhao Heming wrote:
> this patch makes gcc happy with compiling option: [-Wstringop-overflow=]
>
> Signed-off-by: Zhao Heming <heming.zhao@suse.com>
> ---
> device_mapper/libdm-common.c | 2 +-
> lib/activate/fs.c | 2 +-
> libdm/libdm-common.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c
> index bc691d6..3627457 100644
> --- a/device_mapper/libdm-common.c
> +++ b/device_mapper/libdm-common.c
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-08-20 16:05 [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array Zhao Heming
2020-08-20 16:08 ` heming.zhao
@ 2020-08-26 5:18 ` heming.zhao
2020-08-28 19:32 ` Zdenek Kabelac
1 sibling, 1 reply; 7+ messages in thread
From: heming.zhao @ 2020-08-26 5:18 UTC (permalink / raw)
To: linux-lvm; +Cc: mcsontos
ping.
@Marian & other maintainers
On 8/21/20 12:05 AM, Zhao Heming wrote:
> this patch makes gcc happy with compiling option: [-Wstringop-overflow=]
>
> Signed-off-by: Zhao Heming <heming.zhao@suse.com>
> ---
> device_mapper/libdm-common.c | 2 +-
> lib/activate/fs.c | 2 +-
> libdm/libdm-common.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c
> index bc691d6..3627457 100644
> --- a/device_mapper/libdm-common.c
> +++ b/device_mapper/libdm-common.c
> @@ -1445,7 +1445,7 @@ struct node_op_parms {
> char *old_name;
> int warn_if_udev_failed;
> unsigned rely_on_udev;
> - char names[0];
> + char names[];
> };
>
> static void _store_str(char **pos, char **ptr, const char *str)
> diff --git a/lib/activate/fs.c b/lib/activate/fs.c
> index b2c99fc..96f7df6 100644
> --- a/lib/activate/fs.c
> +++ b/lib/activate/fs.c
> @@ -313,7 +313,7 @@ struct fs_op_parms {
> char *lv_name;
> char *dev;
> char *old_lv_name;
> - char names[0];
> + char names[];
> };
>
> static void _store_str(char **pos, char **ptr, const char *str)
> diff --git a/libdm/libdm-common.c b/libdm/libdm-common.c
> index d75c704..d587c32 100644
> --- a/libdm/libdm-common.c
> +++ b/libdm/libdm-common.c
> @@ -1443,7 +1443,7 @@ struct node_op_parms {
> char *old_name;
> int warn_if_udev_failed;
> unsigned rely_on_udev;
> - char names[0];
> + char names[];
> };
>
> static void _store_str(char **pos, char **ptr, const char *str)
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-08-26 5:18 ` heming.zhao
@ 2020-08-28 19:32 ` Zdenek Kabelac
2020-08-29 3:11 ` heming.zhao
0 siblings, 1 reply; 7+ messages in thread
From: Zdenek Kabelac @ 2020-08-28 19:32 UTC (permalink / raw)
To: LVM general discussion and development, heming.zhao
[-- Attachment #1: Type: text/plain, Size: 1306 bytes --]
Dne 26. 08. 20 v 7:18 heming.zhao@suse.com napsal(a):
> ping.
>
> @Marian & other maintainers
>
>
> On 8/21/20 12:05 AM, Zhao Heming wrote:
>> this patch makes gcc happy with compiling option: [-Wstringop-overflow=]
>>
>> Signed-off-by: Zhao Heming <heming.zhao@suse.com>
>> ---
>> device_mapper/libdm-common.c | 2 +-
>> lib/activate/fs.c | 2 +-
>> libdm/libdm-common.c | 2 +-
>> 3 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c
>> index bc691d6..3627457 100644
>> --- a/device_mapper/libdm-common.c
>> +++ b/device_mapper/libdm-common.c
>> @@ -1445,7 +1445,7 @@ struct node_op_parms {
>> char *old_name;
>> int warn_if_udev_failed;
>> unsigned rely_on_udev;
>> - char names[0];
>> + char names[];
>> };
>>
Hi
Here I don't see much problem with patch itself - except it seems to be
somewhat mysterious. Lvm2 is not strict ISO C compilable - there are far to
many other things which would need to be fixed - thus flexible arrays
shouldn't be an issue.
I'm curious why these 3 were important in your case - while other 26
appearances passed for you just fine (see attachment).
So can you paste what sort of gcc problem do you actually try to solve ?
Regards
Zdenek
[-- Attachment #2: gcc-change-zero-sized-array-to-fexlible-array-II.patch --]
[-- Type: text/x-patch, Size: 8301 bytes --]
From: Zdenek Kabelac <zkabelac@redhat.com>
Date: Fri, 28 Aug 2020 19:15:01 +0200
Subject: gcc: change zero-sized array to fexlible array II
---
base/data-struct/hash.c | 2 +-
base/data-struct/radix-tree-adaptive.c | 2 +-
daemons/lvmlockd/lvmlockd-internal.h | 2 +-
device_mapper/all.h | 6 +++---
device_mapper/misc/dm-ioctl.h | 8 ++++----
lib/device/dev-cache.c | 2 +-
lib/format_text/layout.h | 6 +++---
lib/label/label.c | 2 +-
lib/metadata/lv_manip.c | 2 +-
libdm/datastruct/hash.c | 2 +-
libdm/libdevmapper.h | 6 +++---
libdm/libdm-stats.c | 2 +-
libdm/misc/dm-ioctl.h | 8 ++++----
tools/tools.h | 2 +-
14 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/base/data-struct/hash.c b/base/data-struct/hash.c
index 0a0541d2e..5ef5ed276 100644
--- a/base/data-struct/hash.c
+++ b/base/data-struct/hash.c
@@ -22,7 +22,7 @@ struct dm_hash_node {
void *data;
unsigned data_len;
unsigned keylen;
- char key[0];
+ char key[];
};
struct dm_hash_table {
diff --git a/base/data-struct/radix-tree-adaptive.c b/base/data-struct/radix-tree-adaptive.c
index b9ba4179f..3a46cc14b 100644
--- a/base/data-struct/radix-tree-adaptive.c
+++ b/base/data-struct/radix-tree-adaptive.c
@@ -47,7 +47,7 @@ struct value_chain {
struct prefix_chain {
struct value child;
unsigned len;
- uint8_t prefix[0];
+ uint8_t prefix[];
};
struct node4 {
diff --git a/daemons/lvmlockd/lvmlockd-internal.h b/daemons/lvmlockd/lvmlockd-internal.h
index 191c44926..14bdfeed0 100644
--- a/daemons/lvmlockd/lvmlockd-internal.h
+++ b/daemons/lvmlockd/lvmlockd-internal.h
@@ -158,7 +158,7 @@ struct resource {
struct list_head locks;
struct list_head actions;
char lv_args[MAX_ARGS+1];
- char lm_data[0]; /* lock manager specific data */
+ char lm_data[]; /* lock manager specific data */
};
#define LD_LF_PERSISTENT 0x00000001
diff --git a/device_mapper/all.h b/device_mapper/all.h
index c3c6219e3..ace3b69a0 100644
--- a/device_mapper/all.h
+++ b/device_mapper/all.h
@@ -164,20 +164,20 @@ struct dm_info {
struct dm_deps {
uint32_t count;
uint32_t filler;
- uint64_t device[0];
+ uint64_t device[];
};
struct dm_names {
uint64_t dev;
uint32_t next; /* Offset to next struct from start of this struct */
- char name[0];
+ char name[];
};
struct dm_versions {
uint32_t next; /* Offset to next struct from start of this struct */
uint32_t version[3];
- char name[0];
+ char name[];
};
int dm_get_library_version(char *version, size_t size);
diff --git a/device_mapper/misc/dm-ioctl.h b/device_mapper/misc/dm-ioctl.h
index cc2374c36..49954a764 100644
--- a/device_mapper/misc/dm-ioctl.h
+++ b/device_mapper/misc/dm-ioctl.h
@@ -183,7 +183,7 @@ struct dm_target_spec {
struct dm_target_deps {
uint32_t count; /* Array size */
uint32_t padding; /* unused */
- uint64_t dev[0]; /* out */
+ uint64_t dev[]; /* out */
};
/*
@@ -193,7 +193,7 @@ struct dm_name_list {
uint64_t dev;
uint32_t next; /* offset to the next record from
the _start_ of this */
- char name[0];
+ char name[];
};
/*
@@ -203,7 +203,7 @@ struct dm_target_versions {
uint32_t next;
uint32_t version[3];
- char name[0];
+ char name[];
};
/*
@@ -212,7 +212,7 @@ struct dm_target_versions {
struct dm_target_msg {
uint64_t sector; /* Device sector */
- char message[0];
+ char message[];
};
/*
diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index c3f7c49be..d4e2658aa 100644
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -35,7 +35,7 @@ struct dev_iter {
struct dir_list {
struct dm_list list;
- char dir[0];
+ char dir[];
};
static struct {
diff --git a/lib/format_text/layout.h b/lib/format_text/layout.h
index c3dfe8e7a..df7ed3a78 100644
--- a/lib/format_text/layout.h
+++ b/lib/format_text/layout.h
@@ -33,7 +33,7 @@ struct pv_header_extension {
uint32_t version;
uint32_t flags;
/* NULL-terminated list of bootloader areas */
- struct disk_locn bootloader_areas_xl[0];
+ struct disk_locn bootloader_areas_xl[];
} __attribute__ ((packed));
/* Fields with the suffix _xl should be xlate'd wherever they appear */
@@ -46,7 +46,7 @@ struct pv_header {
/* NULL-terminated list of data areas followed by */
/* NULL-terminated list of metadata area headers */
- struct disk_locn disk_areas_xl[0]; /* Two lists */
+ struct disk_locn disk_areas_xl[]; /* Two lists */
} __attribute__ ((packed));
/*
@@ -76,7 +76,7 @@ struct mda_header {
uint64_t start; /* Absolute start byte of mda_header */
uint64_t size; /* Size of metadata area */
- struct raw_locn raw_locns[0]; /* NULL-terminated list */
+ struct raw_locn raw_locns[]; /* NULL-terminated list */
} __attribute__ ((packed));
struct mda_header *raw_read_mda_header(const struct format_type *fmt,
diff --git a/lib/label/label.c b/lib/label/label.c
index 4d369d4f1..8e68f9303 100644
--- a/lib/label/label.c
+++ b/lib/label/label.c
@@ -43,7 +43,7 @@ struct labeller_i {
struct dm_list list;
struct labeller *l;
- char name[0];
+ char name[];
};
static struct dm_list _labellers;
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index c47ec72e2..95ca2df39 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -1798,7 +1798,7 @@ struct alloc_handle {
* Contains area_count lists of areas allocated to data stripes
* followed by log_area_count lists of areas allocated to log stripes.
*/
- struct dm_list alloced_areas[0];
+ struct dm_list alloced_areas[];
};
/*
diff --git a/libdm/datastruct/hash.c b/libdm/datastruct/hash.c
index 4c940039a..726347ea2 100644
--- a/libdm/datastruct/hash.c
+++ b/libdm/datastruct/hash.c
@@ -20,7 +20,7 @@ struct dm_hash_node {
void *data;
unsigned data_len;
unsigned keylen;
- char key[0];
+ char key[];
};
struct dm_hash_table {
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index e9b140563..059b96f0b 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -165,20 +165,20 @@ struct dm_info {
struct dm_deps {
uint32_t count;
uint32_t filler;
- uint64_t device[0];
+ uint64_t device[];
};
struct dm_names {
uint64_t dev;
uint32_t next; /* Offset to next struct from start of this struct */
- char name[0];
+ char name[];
};
struct dm_versions {
uint32_t next; /* Offset to next struct from start of this struct */
uint32_t version[3];
- char name[0];
+ char name[];
};
int dm_get_library_version(char *version, size_t size);
diff --git a/libdm/libdm-stats.c b/libdm/libdm-stats.c
index 5379bed5e..f8d79d807 100644
--- a/libdm/libdm-stats.c
+++ b/libdm/libdm-stats.c
@@ -65,7 +65,7 @@ struct dm_histogram {
const struct dm_stats_region *region;
uint64_t sum; /* Sum of histogram bin counts. */
int nr_bins; /* Number of histogram bins assigned. */
- struct dm_histogram_bin bins[0];
+ struct dm_histogram_bin bins[];
};
/*
diff --git a/libdm/misc/dm-ioctl.h b/libdm/misc/dm-ioctl.h
index 52a7a93d1..55dee2148 100644
--- a/libdm/misc/dm-ioctl.h
+++ b/libdm/misc/dm-ioctl.h
@@ -183,7 +183,7 @@ struct dm_target_spec {
struct dm_target_deps {
uint32_t count; /* Array size */
uint32_t padding; /* unused */
- uint64_t dev[0]; /* out */
+ uint64_t dev[]; /* out */
};
/*
@@ -193,7 +193,7 @@ struct dm_name_list {
uint64_t dev;
uint32_t next; /* offset to the next record from
the _start_ of this */
- char name[0];
+ char name[];
};
/*
@@ -203,7 +203,7 @@ struct dm_target_versions {
uint32_t next;
uint32_t version[3];
- char name[0];
+ char name[];
};
/*
@@ -212,7 +212,7 @@ struct dm_target_versions {
struct dm_target_msg {
uint64_t sector; /* Device sector */
- char message[0];
+ char message[];
};
/*
diff --git a/tools/tools.h b/tools/tools.h
index 4b944e2fd..befff5708 100644
--- a/tools/tools.h
+++ b/tools/tools.h
@@ -110,7 +110,7 @@ struct arg_values {
struct arg_value_group_list {
struct dm_list list;
uint32_t prio;
- struct arg_values arg_values[0];
+ struct arg_values arg_values[];
};
#define PERMITTED_READ_ONLY 0x00000002
--
2.27.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-08-28 19:32 ` Zdenek Kabelac
@ 2020-08-29 3:11 ` heming.zhao
2020-09-02 15:22 ` Zdenek Kabelac
0 siblings, 1 reply; 7+ messages in thread
From: heming.zhao @ 2020-08-29 3:11 UTC (permalink / raw)
To: Zdenek Kabelac, LVM general discussion and development; +Cc: dcermak
On 8/29/20 3:32 AM, Zdenek Kabelac wrote:
> Dne 26. 08. 20 v 7:18 heming.zhao@suse.com napsal(a):
>> ping.
>>
>> @Marian & other maintainers
>>
>>
>> On 8/21/20 12:05 AM, Zhao Heming wrote:
>>> this patch makes gcc happy with compiling option: [-Wstringop-overflow=]
>>>
>>> Signed-off-by: Zhao Heming <heming.zhao@suse.com>
>>> ---
>>> �� device_mapper/libdm-common.c | 2 +-
>>> �� lib/activate/fs.c����������� | 2 +-
>>> �� libdm/libdm-common.c�������� | 2 +-
>>> �� 3 files changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c
>>> index bc691d6..3627457 100644
>>> --- a/device_mapper/libdm-common.c
>>> +++ b/device_mapper/libdm-common.c
>>> @@ -1445,7 +1445,7 @@ struct node_op_parms {
>>> ������ char *old_name;
>>> ������ int warn_if_udev_failed;
>>> ������ unsigned rely_on_udev;
>>> -��� char names[0];
>>> +��� char names[];
>>> �� };
>
>
> Hi
>
> Here I don't see much problem with patch itself - except it seems to be somewhat mysterious. Lvm2 is not strict ISO C compilable - there are far to many other things which would need to be fixed - thus flexible arrays shouldn't be an issue.
>
> I'm curious why these 3 were important in your case - while other 26 appearances passed for you just fine (see attachment).
>
> So can you paste what sort of gcc problem do you actually try to solve ?
>
> Regards
>
> Zdenek
These 3 zero-sized array blocked me to create lvm2 package for opensuse tumbleweed.
Opensuse uses OBS (open build service: https://openbuildservice.org/) to create rpm packages.
In my eyes, the OBS is black-box, it only showed these 3 warning and stopped building work.
So I filed patch only about these 3 places.
the build error just related with [-Wstringop-overflow=]
```
[ 72s] In function 'strcpy',
[ 72s] inlined from '_store_str' at device_mapper/libdm-common.c:1453:2,
[ 72s] inlined from '_stack_node_op' at device_mapper/libdm-common.c:1589:2:
[ 72s] /usr/include/bits/string_fortified.h:90:10: warning: '__builtin_strcpy' writing 1 or more bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
[ 72s] 90 | return __builtin___strcpy_chk (__dest, __src, __bos (__dest));
```
thanks,
heming
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-08-29 3:11 ` heming.zhao
@ 2020-09-02 15:22 ` Zdenek Kabelac
2020-09-03 14:58 ` heming.zhao
0 siblings, 1 reply; 7+ messages in thread
From: Zdenek Kabelac @ 2020-09-02 15:22 UTC (permalink / raw)
To: LVM general discussion and development, heming.zhao; +Cc: dcermak
Dne 29. 08. 20 v 5:11 heming.zhao@suse.com napsal(a):
>
> These 3 zero-sized array blocked me to create lvm2 package for opensuse tumbleweed.
> Opensuse uses OBS (open build service: https://openbuildservice.org/) to create rpm packages.
> In my eyes, the OBS is black-box, it only showed these 3 warning and stopped building work.
> So I filed patch only about these 3 places.
>
> the build error just related with [-Wstringop-overflow=]
> ```
> [ 72s] In function 'strcpy',
> [ 72s] inlined from '_store_str' at device_mapper/libdm-common.c:1453:2,
> [ 72s] inlined from '_stack_node_op' at device_mapper/libdm-common.c:1589:2:
> [ 72s] /usr/include/bits/string_fortified.h:90:10: warning: '__builtin_strcpy' writing 1 or more bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
> [ 72s] 90 | return __builtin___strcpy_chk (__dest, __src, __bos (__dest));
> ```
>
Hi
So patches have've been pushed into master HEAD - so maybe you can try to
validate whether this changes things for your builder server - we can then
consider backporting to stable-2.0 branch.
Regards
Zdenek
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [linux-lvm] [PATCH] gcc: change zero-sized array to fexlible array
2020-09-02 15:22 ` Zdenek Kabelac
@ 2020-09-03 14:58 ` heming.zhao
0 siblings, 0 replies; 7+ messages in thread
From: heming.zhao @ 2020-09-03 14:58 UTC (permalink / raw)
To: Zdenek Kabelac, LVM general discussion and development; +Cc: dcermak
Hello Zdenek,
For dependency, I patched below 3 patches, the opensuse tumbleweed building completed successfully
```
^ permalink raw reply [flat|nested] 7+ messages in thread
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2020-08-28 19:32 ` Zdenek Kabelac
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