From: Bertrand Marquis <Bertrand.Marquis@arm.com>
To: "open list:X86" <xen-devel@lists.xenproject.org>
Cc: "jgross@suse.com" <jgross@suse.com>,
Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH v3 1/2] tools/libs/stat: use memcpy instead of strncpy in getBridge
Date: Wed, 14 Oct 2020 10:58:33 +0000 [thread overview]
Message-ID: <A6CDE62A-13F4-491B-BE0B-180657136504@arm.com> (raw)
In-Reply-To: <4ecb03b40b0da6d480e95af1da8289501a3ede0a.1602078276.git.bertrand.marquis@arm.com>
Hi,
Could this be reviewed so that gcc10 issues are fixed ?
Thanks
Bertrand
> On 7 Oct 2020, at 14:57, Bertrand Marquis <bertrand.marquis@arm.com> wrote:
>
> Use memcpy in getBridge to prevent gcc warnings about truncated
> strings. We know that we might truncate it, so the gcc warning
> here is wrong.
> Revert previous change changing buffer sizes as bigger buffers
> are not needed.
>
> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
> ---
> Changes in v3:
> Do a memset 0 on destination buffer and use MIN between string length
> and resultLen - 1.
> Changes in v2:
> Use MIN between string length of de->d_name and resultLen to copy only
> the minimum size required and prevent crossing to from an unallocated
> space.
> ---
> tools/libs/stat/xenstat_linux.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/tools/libs/stat/xenstat_linux.c b/tools/libs/stat/xenstat_linux.c
> index d2ee6fda64..e0d242e1bc 100644
> --- a/tools/libs/stat/xenstat_linux.c
> +++ b/tools/libs/stat/xenstat_linux.c
> @@ -29,6 +29,7 @@
> #include <string.h>
> #include <unistd.h>
> #include <regex.h>
> +#include <xen-tools/libs.h>
>
> #include "xenstat_priv.h"
>
> @@ -78,8 +79,14 @@ static void getBridge(char *excludeName, char *result, size_t resultLen)
> sprintf(tmp, "/sys/class/net/%s/bridge", de->d_name);
>
> if (access(tmp, F_OK) == 0) {
> - strncpy(result, de->d_name, resultLen);
> - result[resultLen - 1] = 0;
> + /*
> + * Do not use strncpy to prevent compiler warning with
> + * gcc >= 10.0
> + * If de->d_name is longer then resultLen we truncate it
> + */
> + memset(result, 0, resultLen);
> + memcpy(result, de->d_name, MIN(strnlen(de->d_name,
> + NAME_MAX),resultLen - 1));
> }
> }
> }
> @@ -264,7 +271,7 @@ int xenstat_collect_networks(xenstat_node * node)
> {
> /* Helper variables for parseNetDevLine() function defined above */
> int i;
> - char line[512] = { 0 }, iface[16] = { 0 }, devBridge[256] = { 0 }, devNoBridge[257] = { 0 };
> + char line[512] = { 0 }, iface[16] = { 0 }, devBridge[16] = { 0 }, devNoBridge[17] = { 0 };
> unsigned long long rxBytes, rxPackets, rxErrs, rxDrops, txBytes, txPackets, txErrs, txDrops;
>
> struct priv_data *priv = get_priv_data(node->handle);
> --
> 2.17.1
>
>
next prev parent reply other threads:[~2020-10-14 10:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 13:57 [PATCH v3 1/2] tools/libs/stat: use memcpy instead of strncpy in getBridge Bertrand Marquis
2020-10-07 13:57 ` [PATCH v3 2/2] tool/libs/light: Fix libxenlight gcc warning Bertrand Marquis
2020-10-08 12:57 ` Wei Liu
2020-10-14 10:58 ` Bertrand Marquis [this message]
2020-10-14 15:47 ` [PATCH v3 1/2] tools/libs/stat: use memcpy instead of strncpy in getBridge Wei Liu
2020-10-14 15:54 ` Bertrand Marquis
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