perf tools: Make fetch_kernel_version() publicly available

There are 2 places in llvm-utils.c which find kernel version information
through uname. This patch extracts the uname related code into a
fetch_kernel_version() function and puts it into util.h so it can be
reused.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446818135-87310-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index cd12c25e4ea4..47b1e36c7ea0 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -3,6 +3,7 @@
 #include "debug.h"
 #include <api/fs/fs.h>
 #include <sys/mman.h>
+#include <sys/utsname.h>
 #ifdef HAVE_BACKTRACE_SUPPORT
 #include <execinfo.h>
 #endif
@@ -665,3 +666,32 @@ bool find_process(const char *name)
 	closedir(dir);
 	return ret ? false : true;
 }
+
+int
+fetch_kernel_version(unsigned int *puint, char *str,
+		     size_t str_size)
+{
+	struct utsname utsname;
+	int version, patchlevel, sublevel, err;
+
+	if (uname(&utsname))
+		return -1;
+
+	if (str && str_size) {
+		strncpy(str, utsname.release, str_size);
+		str[str_size - 1] = '\0';
+	}
+
+	err = sscanf(utsname.release, "%d.%d.%d",
+		     &version, &patchlevel, &sublevel);
+
+	if (err != 3) {
+		pr_debug("Unablt to get kernel version from uname '%s'\n",
+			 utsname.release);
+		return -1;
+	}
+
+	if (puint)
+		*puint = (version << 16) + (patchlevel << 8) + sublevel;
+	return 0;
+}