tools: iio: iio_generic_buffer: make num_loops signed

commit b119d3bc328e7a9574861ebe0c2110e2776c2de1 upstream.

Currently, num_loops is unsigned, but it's set by strtoll, which returns a
(signed) long long int. This could lead to overflow, and it also makes the
check "num_loops < 0" always be false, since num_loops is unsigned.
Setting num_loops to -1 to loop forever is almost working because num_loops
is getting set to a very high number, but it's technically still incorrect.

Fix this issue by making num_loops signed. This also fixes an error found
by Smatch.

Signed-off-by: Martin Kelly <mkelly@xevo.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 55dda0abcf9d ("tools: iio: iio_generic_buffer: allow continuous looping")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c
index 3040830..8454566 100644 (file)
--- a/tools/iio/iio_generic_buffer.c
+++ b/tools/iio/iio_generic_buffer.c
@@ -330,7 +330,7 @@ static const struct option longopts[] = {
 
 int main(int argc, char **argv)
 {
-       unsigned long long num_loops = 2;
+       long long num_loops = 2;
        unsigned long timedelay = 1000000;
        unsigned long buf_len = 128;