On Sun, Nov 11, 2007 at 11:29:59AM +0800, Miao Xie wrote: >on 2007-11-8 20:11 WANG Cong wrote: >>On Thu, Nov 08, 2007 at 07:47:41PM +0800, WANG Cong wrote: >>>Yes, snprintf is safer than sprintf. But here, the 'count' will be >>>mis-pointed when snprintf returns no less than PAGE_SIZE (what you called >>>overflow). So you may also need: >>> >>> if (unlikely(count >= PAGE_SIZE)) >>> count = PAGE_SIZE - 1; >>> >>>Just a simple guess. ;) >> >>Or try scnprintf. ;) > >We have discussed this problem. We think that it is better to return the >return >value of kernel directly because this is the specification of the sysfs. > > (Version:2.6.24-rc2,File:Documentation/filesystems/sysfs.txt:198-201): > 198 - show() methods should return the number of bytes printed into the > 199 buffer. This is the return value of snprintf(). > 200 > 201 - show() should always use snprintf(). > >And the function which calls the show() methods uses BUG_ON() to check the >return value. If the return value is too big,it means something wrong. > >If we use scnprintf, we may not know whether the resulting string is >truncated >or not. Maybe A big bug is ignored. >
Well, i know little about sysfs. So it was just a hint. Anyway, thanks for your input! - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
