On Sun, Mar 22, 2020 at 02:25:42AM +0200, Andy Shevchenko wrote: > On Wed, Mar 18, 2020 at 08:25:22PM +0530, Rohit Sarkar wrote: > > scnprintf returns the actual number of bytes written into the buffer as > > opposed to snprintf which returns the number of bytes that would have > > been written if the buffer was big enough. Using the output of snprintf > > may lead to difficult to detect bugs. > > Nice. Have you investigate the code? > > > @@ -96,7 +96,7 @@ static ssize_t adis16136_show_serial(struct file *file, > > if (ret) > > return ret; > > > > - len = snprintf(buf, sizeof(buf), "%.4x%.4x%.4x-%.4x\n", lot1, lot2, > > + len = scnprintf(buf, sizeof(buf), "%.4x%.4x%.4x-%.4x\n", lot1, lot2, > > lot3, serial); > > > > return simple_read_from_buffer(userbuf, count, ppos, buf, len); > > The buffer size is 20, the pattern size I count to 19. Do you think snprintf() > can fail? That might be the case, but IMO using scnprintf can be considered as a best practice. There is no overhead with this change and further if the pattern is changed by someone in the future they might overlook the buffersize Thanks, Rohit > -- > With Best Regards, > Andy Shevchenko > >
