[PATCH 1/1] makedevs: set path size to match linux

[Matthew Weber]

All,

On Tue, Jun 27, 2017 at 8:36 AM, Jared Bents
<jared.bents at rockwellcollins.com> wrote:
> On Mon, Jun 26, 2017 at 10:31 PM, Baruch Siach <baruch at tkos.co.il> wrote:
>> Hi Matthew,
>>
>> On Mon, Jun 26, 2017 at 08:45:42PM -0500, Matthew Weber wrote:
>>> On Mon, Jun 26, 2017 at 7:36 PM, Emmanuel Deloget <logout at free.fr> wrote:
>>> > On Mon, Jun 26, 2017 at 11:23 PM, Matthew Weber
>>> > <matthew.weber at rockwellcollins.com> wrote:
>>> >> On Mon, Jun 26, 2017 at 3:55 PM, Baruch Siach <baruch at tkos.co.il> wrote:
>>> >> > On Mon, Jun 26, 2017 at 03:33:09PM -0500, Matt Weber wrote:
>>> >> >> From: Jared Bents <jared.bents at rockwellcollins.com>
>>> >> >>
>>> >> >> Update to increase the pathname limit to the
>>> >> >> linux limit of 4096 characters.
>>> >> >>
>>> >> >> Similar patch:
>>> >> >> https://patchwork.openembedded.org/patch/131475/
>>> >> >>
>>> >> >> Signed-off-by: Jared Bents <jared.bents at rockwellcollins.com>
>>> >> >> Signed-off-by: Matt Weber <matthew.weber at rockwellcollins.com>
>>> >> >> ---
>>> >> >>  miscutils/makedevs.c | 4 ++--
>>> >> >>  1 file changed, 2 insertions(+), 2 deletions(-)
>>> >> >>
>>> >> >> diff --git a/miscutils/makedevs.c b/miscutils/makedevs.c
>>> >> >> index 9e7ca34..0049edb 100644
>>> >> >> --- a/miscutils/makedevs.c
>>> >> >> +++ b/miscutils/makedevs.c
>>> >> >> @@ -208,7 +208,7 @@ int makedevs_main(int argc UNUSED_PARAM, char
>>> >> >> **argv)
>>> >> >>               unsigned count = 0;
>>> >> >>               unsigned increment = 0;
>>> >> >>               unsigned start = 0;
>>> >> >> -             char name[41];
>>> >> >> +             char name[4096];
>>> >> >
>>> >> > Why not use PATH_MAX here?
>>> >>
>>> >> Agree, that would be cleaner.  Will submit v2 after some testing.
>>> >>
>>> >> That still leaves a hardcoded value in the sscanf  of 4095........
>>> >> should I add a comment to the affect we're assuming PATH_MAX is at
>>> >> least 4096?  Maybe a check is also needed?
>>> >
>>> >
>>> > Alternatively you may use the m modifier, when implemented, to auto-allocate
>>> > the name pointer. This way you don't have to hardcode anything in the
>>> > sscanf(), you let the library for the job for you. Later, you can check the
>>> > string length.
>>> >
>>> > Such a change would induce an allocation, a free but will also reduce stack
>>> > usage.
>>> >
>>>
>>> If we want to keep it all static, another option would be to stringify
>>> that define.
>>> (Courtesy Jared for this idea)
>>>
>>> + #define STRINGIFY(x) STRINGIFY2(x)
>>> + #define STRINGIFY2(x) #x
>>> .....
>>> - if ((2 > sscanf(line, "%40s %c %o %40s %40s %u %u %u %u %u",
>>> + if ((2 > sscanf(line, "%" STRINGIFY(PATH_MAX) "s %c %o %40s %40s %u
>>> %u %u %u %u",
>>
>> You need 'STRINGIFY(PATH_MAX-1)'. I'm not sure this does what you mean.
>>

Superseded by: http://lists.busybox.net/pipermail/busybox/2017-July/085570.html

Matt