Hi David, > Date: 2026-11-05 11:28:13+0000 > From: David Laight > > On Tue, 3 Nov 2026 22:23:18 -0800 > Mariia Nikitash wrote: > > > In preparation for removing the deprecated strlcat() API[1], use > > strscpy() to initialize the mouse device name. > > > > The destination is zero-initialized, and the constant string fits > > within the buffer. Since the return value is unused, this preserves > > the existing behavior. > > > > Link: https://github.com/KSPP/linux/issues/370 [1] > > Signed-off-by: Mariia Nikitash > > --- > > drivers/input/mouse/vsxxxaa.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/input/mouse/vsxxxaa.c b/drivers/input/mouse/vsxxxaa.c > > index 042a17fe81db..b3a0d7ff5738 100644 > > --- a/drivers/input/mouse/vsxxxaa.c > > +++ b/drivers/input/mouse/vsxxxaa.c > > @@ -463,8 +463,8 @@ static int vsxxxaa_connect(struct serio *serio, struct serio_driver *drv) > > > > mouse->dev = input_dev; > > mouse->serio = serio; > > - strlcat(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer", > > - sizeof(mouse->name)); > > + strscpy(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer", > > + sizeof(mouse->name)); > > You might as well use the 2 argument form. > Moreover, if you use strcpy() you'll get a compile-time error if the > string doesn't fit. > strscpy() will truncate and return an errors. > > The other question is whether mouse->name even has to be char[]. > > Personally I think that while there are issues with strlcat() > (mostly to do with its return value), and that there are often > much better (and faster - so sprintf is out) ways of getting > the same result, the deprecation really needs to propose a > sensible alternative (not inlined strlen() + strscpy()). One alternative would be to add strscat(), with the obvious internal strlen(3). This would be a drop-in replacement, and wouldn't have the issues of strlcat(3) --mainly, the DoS vulnerability which is consequence of the return value, and also the more difficult error handling of doing '>=sizeof(...)' than '<0'--. There's an implementation of strscat() in shadow-utils, where we call it strtcat() --because what it does is Truncating the string, so a T feels more appropriate--: Another alternative which would avoid the internal strlen(3) call, and thus would be faster, would be to add a stpecpy() function, similar to stpcpy(3), but which would take a pointer one-past-the-last element in the buffer, to perform truncation. This is fundamentally Plan9's strecpy(2), except that Plan9's API has a bug. There's an implementation of stpecpy() in shadow-utils: We've been using stpecpy() quite extensively in shadow-utils, and it's a great API. Of course, there's also the decades-long experience in Plan9, which apart from their bug --which I found, by comparing their implementation to mine--, shows that it's a quite useful API. And stpecpy() produces the simplest code of all truncating functions. Have a lovely day! Alex > This case is, of course one of the 'better ways' cases. > > David > > > snprintf(mouse->phys, sizeof(mouse->phys), "%s/input0", serio->phys); > > > > input_dev->name = mouse->name; > > --