On Wed, Nov 23, 2011 at 10:32:33PM +0530, Aruna Balakrishnaiah wrote:
> Signed-off-by: Aruna Balakrishnaiah <aruna@xxxxxxxxxxxxxxxxxx>
>
> lsusb throws unusual error message "unable to initialize libusb: -99"
> with exit status of 1 when usb devices are not listed. Patch handles it
> without printing anything and returns exit status of 0.
Why would we want to return "good" if there was an error?
> ---
> lsusb.c | 27 ++++++++++++++++++++++++++-
> 1 files changed, 26 insertions(+), 1 deletions(-)
>
> diff --git a/lsusb.c b/lsusb.c
> index 37c43f7..081d42e 100644
> --- a/lsusb.c
> +++ b/lsusb.c
> @@ -44,6 +44,7 @@
> #include "usbmisc.h"
>
> #include <getopt.h>
> +#include <dirent.h>
>
> #define le16_to_cpu(x) libusb_cpu_to_le16(libusb_cpu_to_le16(x))
>
> @@ -108,6 +109,7 @@
> #define HUB_STATUS_BYTELEN 3 /* max 3 bytes status = hub + 23 ports */
>
> static const char procbususb[] = "/proc/bus/usb";
> +static const char sysbususb[] = "/sys/bus/usb/devices";
> static unsigned int verblevel = VERBLEVEL_DEFAULT;
> static int do_report_desc = 1;
> static const char * const encryption_type[] = {
> @@ -3920,6 +3922,25 @@ static int treedump(void)
> return 0;
> }
>
> +static int check_for_usbdevice(void)
> +{
> + struct dirent *d;
> + int n = 0;
> + DIR *dir = opendir(sysbususb);
> +
> + while ((d = readdir(dir)) != NULL) {
> + if (++n > 2)
> + break;
> + }
> +
> + closedir(dir);
> +
> + if (n <= 2)
> + return 1;
> + else
> + return 0;
> +}
No, we don't want to be doing this, this is why we use libusb, it
handles this type of thing for us.
> +
> /* ---------------------------------------------------------------------- */
>
> int main(int argc, char *argv[])
> @@ -4027,7 +4048,11 @@ int main(int argc, char *argv[])
> strerror(err));
> status = 0;
>
> - err = libusb_init(&ctx);
> + if (check_for_usbdevice())
> + return 0;
Again, returning 0 for when there is an error is not a good idea.
Why is the existing code somehow not working properly for you? When
USB devices can't be found, it's good to return an error, right?
greg k-h
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