> -----Original Message-----
> From: Marek Vasut [mailto:ma...@denx.de]
> Sent: Wednesday, June 01, 2016 6:51 PM
> To: Rajesh Bhagat <rajesh.bha...@nxp.com>; u-boot@lists.denx.de
> Cc: york sun <york....@nxp.com>; Sriram Dash <sriram.d...@nxp.com>
> Subject: Re: [PATCH] drivers: usb: fsl: Fix NULL terminating issue for usb
> controller
> name string
>
> On 06/01/2016 01:17 PM, Rajesh Bhagat wrote:
> > Fixes NULL terminating issue for usb controller name string and
> > performs code cleanup for intializing variables current_usb_controller
> > and usb_phy.
> >
> > Signed-off-by: Rajesh Bhagat <rajesh.bha...@nxp.com>
> > ---
> > drivers/usb/host/ehci-fsl.c | 10 ++++------
> > 1 files changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> > index a43d37d..a806993 100644
> > --- a/drivers/usb/host/ehci-fsl.c
> > +++ b/drivers/usb/host/ehci-fsl.c
> > @@ -49,11 +49,9 @@ int ehci_hcd_init(int index, enum usb_init_type init,
> > struct usb_ehci *ehci = NULL;
> > const char *phy_type = NULL;
> > size_t len;
> > - char current_usb_controller[5];
> > + char current_usb_controller[5] = {0};
> > #ifdef CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY
> > - char usb_phy[5];
> > -
> > - usb_phy[0] = '\0';
> > + char usb_phy[5] = {0};
> > #endif
> > if (has_erratum_a007075()) {
> > /*
> > @@ -64,8 +62,8 @@ int ehci_hcd_init(int index, enum usb_init_type init,
> > */
> > mdelay(5);
> > }
> > - memset(current_usb_controller, '\0', 5);
> > - snprintf(current_usb_controller, 4, "usb%d", index+1);
> > + snprintf(current_usb_controller, sizeof(current_usb_controller),
> > + "usb%d", index+1);
>
> What is the actual problem here ? snprintf() will add the \0 at the end of
> the string, so
> I don't see any "null terminating issue" in the code.
> I can understand using the sizeof() in the snprintf(), which is valid, but
> that's all.
>
Hello Marek,
It is surprising for me too, but same can be verified even on x86 machine using
below test
program, Can it be compiler optimization of memset?
Output #1 : current_usb_controller usb
Output #2 : current_usb_controller usb1 (Expected Output)
int main()
{
int index = 0;
#if 1
char current_usb_controller[5];
memset(current_usb_controller, '\0', 5);
snprintf(current_usb_controller, 4, "usb%d", index+1);
#else
char current_usb_controller[5] = {0};
snprintf(current_usb_controller, sizeof(current_usb_controller),
"usb%d", index+1);
#endif
printf("current_usb_controller %s\n", current_usb_controller);
return 0;
}
Best Regards,
Rajesh Bhagat
> > switch (index) {
> > case 0:
> >
>
>
> --
> Best regards,
> Marek Vasut
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