[xen stable-4.9] tools/libxc: fix strncpy size

[patchbot@xxxxxxx]

commit 9737f89b076ae4d05e6f974a7c21aced4459966e
Author:     Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Thu Apr 5 03:50:49 2018 +0200
Commit:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
CommitDate: Fri Jun 12 17:01:39 2020 +0100

    tools/libxc: fix strncpy size
    
    gcc-8 warns about possible truncation of trailing '\0'.
    Final character is overridden by '\0' anyway, so don't bother to copy
    it.
    
    This fixes compile failure:
    
        xc_pm.c: In function 'xc_set_cpufreq_gov':
        xc_pm.c:308:5: error: 'strncpy' specified bound 16 equals destination 
size [-Werror=stringop-truncation]
             strncpy(scaling_governor, govname, CPUFREQ_NAME_LEN);
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        cc1: all warnings being treated as errors
    
    Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
    Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Release-Acked-by: Juergen Gross <jgross@xxxxxxxx>
    (cherry picked from commit fa7789ef18bd2e716997937af71b2e4b5b00a159)
---
 tools/libxc/xc_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/libxc/xc_pm.c b/tools/libxc/xc_pm.c
index ae917bc630..0fc47047ce 100644
--- a/tools/libxc/xc_pm.c
+++ b/tools/libxc/xc_pm.c
@@ -305,7 +305,7 @@ int xc_set_cpufreq_gov(xc_interface *xch, int cpuid, char 
*govname)
     sysctl.cmd = XEN_SYSCTL_pm_op;
     sysctl.u.pm_op.cmd = SET_CPUFREQ_GOV;
     sysctl.u.pm_op.cpuid = cpuid;
-    strncpy(scaling_governor, govname, CPUFREQ_NAME_LEN);
+    strncpy(scaling_governor, govname, CPUFREQ_NAME_LEN - 1);
     scaling_governor[CPUFREQ_NAME_LEN - 1] = '\0';
 
     return xc_sysctl(xch, &sysctl);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9