[xen staging-4.14] tools/libs/stat: use memcpy instead of strncpy in getBridge

[patchbot@xxxxxxx]

commit a38060ece699f22cd317219bec53c0d27279155b
Author:     Bertrand Marquis <bertrand.marquis@xxxxxxx>
AuthorDate: Wed Oct 7 14:57:01 2020 +0100
Commit:     Ian Jackson <iwj@xxxxxxxxxxxxxx>
CommitDate: Mon Nov 9 17:45:32 2020 +0000

    tools/libs/stat: use memcpy instead of strncpy in getBridge
    
    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@xxxxxxx>
    Acked-by: Wei Liu <wl@xxxxxxx>
    (cherry picked from commit 40fe714ca4245a9716264fcb3ee8df42c3650cf6)
---
 tools/xenstat/libxenstat/src/xenstat_linux.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/xenstat/libxenstat/src/xenstat_linux.c 
b/tools/xenstat/libxenstat/src/xenstat_linux.c
index 0274dc4d07..9c0cb277c5 100644
--- a/tools/xenstat/libxenstat/src/xenstat_linux.c
+++ b/tools/xenstat/libxenstat/src/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 @@ 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);
--
generated by git-patchbot for /home/xen/git/xen.git#staging-4.14