perf tools: Use scnprintf where applicable

Several places were expecting that the value returned was the number of
characters printed, not what would be printed if there was space.

Fix it by using the scnprintf and vscnprintf variants we inherited from
the kernel sources.

Some corner cases where the number of printed characters were not
accounted were fixed too.

Reported-by: Anton Blanchard <anton@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/n/tip-kwxo2eh29cxmd8ilixi2005x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/tools/perf/arch/powerpc/util/header.c b/tools/perf/arch/powerpc/util/header.c
index eba80c292945..2f7073d107fd 100644
--- a/tools/perf/arch/powerpc/util/header.c
+++ b/tools/perf/arch/powerpc/util/header.c
@@ -25,7 +25,7 @@ get_cpuid(char *buffer, size_t sz)
 
         pvr = mfspr(SPRN_PVR);
 
-        nb = snprintf(buffer, sz, "%lu,%lu$", PVR_VER(pvr), PVR_REV(pvr));
+        nb = scnprintf(buffer, sz, "%lu,%lu$", PVR_VER(pvr), PVR_REV(pvr));
 
         /* look for end marker to ensure the entire data fit */
         if (strchr(buffer, '$')) {
diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
index f94006068d2b..146d12a1cec0 100644
--- a/tools/perf/arch/x86/util/header.c
+++ b/tools/perf/arch/x86/util/header.c
@@ -48,7 +48,7 @@ get_cpuid(char *buffer, size_t sz)
                 if (family >= 0x6)
                         model += ((a >> 16) & 0xf) << 4;
         }
-        nb = snprintf(buffer, sz, "%s,%u,%u,%u$", vendor, family, model, step);
+        nb = scnprintf(buffer, sz, "%s,%u,%u,%u$", vendor, family, model, step);
 
         /* look for end marker to ensure the entire data fit */
         if (strchr(buffer, '$')) {