Messages in this thread | | | Date | Tue, 27 Nov 2012 20:41:11 +0000 | From | Ben Hutchings <> | Subject | Re: [PATCH 1/3] tools/hv: Fix for long file names from readdir |
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On Tue, Nov 27, 2012 at 03:28:25PM -0500, Tomas Hozza wrote: > > > ----- Original Message ----- > > On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote: > > > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically > > > sized buffers which could be too small to store really long names. > > > > > > Buffer sizes have been changed to PATH_MAX, include "limits.h" > > > where > > > PATH_MAX is defined was added and length checks ware added via > > > snprintf. > > [...] > > > > PATH_MAX has nothing to do with any actual kernel limit; it's no more > > meaningful than the current value of 256. Network interface names > > are > > limited to 15 characters, thus the current array is more than long > > enough. So I think this is entirely unnecessary. > > This is just for sanity. The value PATH_MAX was chosen after discussion > with K. Y. Srinivasan and Olaf Hering instead of some "magic" number like > 256 or 512.
PATH_MAX is a magic name.
> > Using snprintf() is a good idea, but you need to check the return > > value and handle the truncation case somehow. > > By using PATH_MAX sized buffer there is no need for handling the truncation > case.
You are claiming two contradictory things: sprintf() may overrun the buffer, so we need the length check provided by snprintf(), but there is no need to check for truncation because we know the length is sufficient.
Ben.
-- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus
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