On Mon, 31 Oct 2016, Kieran Bingham wrote: > On 31/10/16 13:55, Peter Rosin wrote: > > On 2016-10-26 10:53, Lee Jones wrote: > >> On Tue, 25 Oct 2016, Kieran Bingham wrote: > >> > >>> If a user provides a shortened string to match a device to the sysfs i2c > >>> interface it will match on the first string that contains that string > >>> prefix. > >>> > >>> for example: > >>> echo a 0x68 > /sys/bus/i2c/devices/i2c-2/new_device > >>> > >>> will match as3711, as3722, and ak8975 incorrectly. > >>> > >>> Signed-off-by: Kieran Bingham <kieran@xxxxxxxxxxx> > >> > >> Acked-by: Lee Jones <lee.jones@xxxxxxxxxx> > >> > >>> --- > >>> drivers/i2c/i2c-core.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > >>> index 01bce56f733a..50c9cfdb87b7 100644 > >>> --- a/drivers/i2c/i2c-core.c > >>> +++ b/drivers/i2c/i2c-core.c > >>> @@ -1708,7 +1708,7 @@ i2c_of_match_device_strip_vendor(const struct of_device_id *matches, > >>> else > >>> name++; > >>> > >>> - if (!strncasecmp(client->name, name, strlen(client->name))) > >>> + if (!strncasecmp(client->name, name, strlen(name))) > >>> return matches; > >>> } > >>> > >> > > > > Is that really so much better? > > My original thought was that it verifies 'more' of the userspace input. > but... > > > With this patch > > echo as3711CRAP 0x68 > /sys/... > > will match as3711. > > > > What if there is some as37112 driver that is the real target? > > You're right - It looks like the only way to do this correctly is to > match the strncasecmp and the strlen of both strings. > > So really we should be using sysfs_streq(). The only limitation there is > that this original code was performing a case-insensitive compare. > > Lee - Where did the requirement for case insensitive matching come from > in your original code. Is it expected to be case-insensitive from the > I2C sysfs interface? or are dt-nodes expected to be case-sensitive? Compatible strings are always lower-case. > Does anyone see reason that this shouldn't be using sysfs_streq()? or do > we need a sysfs_strcaseeq()... ... but I don't see an issue with not being case sensitive. Certainly if it makes the logic easier/more consistent. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
