[PATCH] more Libsysfs updates

On Thu, Mar 11, 2004 at 02:36:23PM +0100, Kay Sievers wrote:
> On Thu, 2004-03-11 at 15:02, Ananth N Mavinakayanahalli wrote:
> > On Thu, Mar 11, 2004 at 02:04:36PM +0100, Kay Sievers wrote:
> > > On Thu, Mar 11, 2004 at 11:53:50AM +0500, Ananth N Mavinakayanahalli wrote:
> > >
> > > > +#define safestrcpy(to, from)	strncpy(to, from, sizeof(to)-1)
> > > > +#define safestrcat(to, from)	strncat(to, from, sizeof(to) - strlen(to)-1)
> > >
> > > These strings are not terminated with '\0' if from is longer than
> > > the sizeof to.
> >
> > Did not do it on purpose as the "to" elements are either calloc'd or memset to
> > '0' explicitly in the library. Thats the reason I mentioned "scaled down" :)
>
> Ahh, sounds good.
>
> > > > +#define safestrncpy(to, from, maxsize) \
> > > > +do { \
> > > > +	to[maxsize-1] = '\0'; \
> > > > +	strncpy(to, from, maxsize-1); \
> > > > +} while (0)
> > > > +
> > > > +#define safestrncat(to, from, maxsize) \
> > > > +do { \
> > > > +	to[maxsize-1] = '\0'; \
> > > > +	strncat(to, from, maxsize - strlen(to)-1); \
> > > > +} while (0)
> > >
> > > We all expect a similar behavior like strncat/strncpy according to the
> > > names, but these macros are limiting by the target size and do not limit
> > > the count of chars copied.
> > > This is confusing I think and suggest using a different name like
> > > 'safestrcopymax()' or something.
> >
> > Good point.. will make the change
>
> Nice. I've had these *n* names too and I forgot about the logic and only
> 10 days later I introduced a ugly bug cause I can't limit the count of
> copied chars :)

Inlined is the patch for this... applies on the earlier _BIG_ patch.

1 files changed, 1 insertions, 1 deletions

diff --git a/libsysfs/sysfs_device.c b/libsysfs/sysfs_device.c
index e3a8977016..290fd9723e 100644
--- a/libsysfs/sysfs_device.c
+++ b/libsysfs/sysfs_device.c
@@ -53,7 +53,7 @@ static int get_dev_driver(struct sysfs_device *dev)
 	if (c == NULL)
 		return 1;
 	*c = '\0';
-	safestrncat(c, path, (sizeof(devpath) - strlen(devpath)));
+	safestrcatmax(c, path, (sizeof(devpath) - strlen(devpath)));
 
 	drvlist = sysfs_open_subsystem_list(path);
 	if (drvlist != NULL) {