Sami Kerola <kerolasa@xxxxxx> writes:
> On 29 May 2017 at 11:09, Karel Zak <kzak@xxxxxxxxxx> wrote:
>> On Sat, May 27, 2017 at 07:24:09PM +0100, Sami Kerola wrote:
>>> lib/sysfs.c:343:31: warning: '/start' directive output may be truncated
>>> writing 6 bytes into a region of size between 1 and 256
>>> [-Wformat-truncation=]
>>>
>>> lib/sysfs.c:372:32: warning: '/partition' directive output may be truncated
>>> writing 10 bytes into a region of size between 1 and 256
>>> [-Wformat-truncation=]
>>>
>>> Signed-off-by: Sami Kerola <kerolasa@xxxxxx>
>>> ---
>>> lib/sysfs.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/sysfs.c b/lib/sysfs.c
>>> index cc290faac..6272b80b4 100644
>>> --- a/lib/sysfs.c
>>> +++ b/lib/sysfs.c
>>> @@ -307,7 +307,7 @@ static struct dirent *xreaddir(DIR *dp)
>>>
>>> int sysfs_is_partition_dirent(DIR *dir, struct dirent *d, const char *parent_name)
>>> {
>>> - char path[256];
>>> + char path[strlen(d->d_name) + sizeof("/start") + 1];
>>>
>>> #ifdef _DIRENT_HAVE_D_TYPE
>>> if (d->d_type != DT_DIR &&
>>> @@ -356,7 +356,6 @@ dev_t sysfs_partno_to_devno(struct sysfs_cxt *cxt, int partno)
>>> {
>>> DIR *dir;
>>> struct dirent *d;
>>> - char path[256];
>>> dev_t devno = 0;
>>>
>>> dir = sysfs_opendir(cxt, NULL);
>>> @@ -365,6 +364,7 @@ dev_t sysfs_partno_to_devno(struct sysfs_cxt *cxt, int partno)
>>>
>>> while ((d = xreaddir(dir))) {
>>> int n, maj, min;
>>> + char path[strlen(d->d_name) + sizeof("/partition") + 1];
>>
>> why strlen() here? Maybe we can add to c.h macro
>>
>> #define ul_dname_sizeof(x)
>> (sizeof(((struct dirent *)0)->d_dname) + sizeof(x) + 1)
>>
>> or use PATH_MAX ...
>
> For some reason I thought d_name would be allocated, in which case
> strlen() would be
> more appropriate. Thank you for pointing out it is very static 255
> buffer, so added the
Is this *defined by standard*? I believe not.
=== man dirent.h ===
The character array d_name is of unspecified size, but the number of
bytes preceding the terminating null byte shall not exceed {NAME_MAX}.
=== cut ===
Same apply to [patch 3/4].
(Of course, both loopdev and sysfs are linux-specific, so
portablity is not very important (however, it is not that unheard of
from glibc or gcc folks to suddenly change those standard-unspecified
things, and then say "don't rely on undefined behavior, baka >_<"; then
again, there are uclibc, dietlibc, klibc, etc)).
> proposed ul_dname_sizeof() to c.h and changed the rest of the commits
> accordingly.
>
> https://github.com/kerolasa/lelux-utiliteetit/commit/5eb0ea80b376e295aca649acc8f8e2eaa91f30bb
>
> Updates to changes are available in the git repository at:
> git://github.com/kerolasa/lelux-utiliteetit.git rc2-fixes
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