perf tools: Add perf_pmu__scan_file()
Add a function to scan a sysfs file within the pmu device directory.
This will be used to read capability values from the PMU 'caps'
subdirectory.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406786474-9306-8-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 438bb26..22a4ad5 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -3,6 +3,7 @@
#include <unistd.h>
#include <stdio.h>
#include <stdbool.h>
+#include <stdarg.h>
#include <dirent.h>
#include <api/fs/fs.h>
#include <locale.h>
@@ -804,3 +805,39 @@
}
return false;
}
+
+static FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
+{
+ struct stat st;
+ char path[PATH_MAX];
+ const char *sysfs;
+
+ sysfs = sysfs__mountpoint();
+ if (!sysfs)
+ return NULL;
+
+ snprintf(path, PATH_MAX,
+ "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);
+
+ if (stat(path, &st) < 0)
+ return NULL;
+
+ return fopen(path, "r");
+}
+
+int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt,
+ ...)
+{
+ va_list args;
+ FILE *file;
+ int ret = EOF;
+
+ va_start(args, fmt);
+ file = perf_pmu__open_file(pmu, name);
+ if (file) {
+ ret = vfscanf(file, fmt, args);
+ fclose(file);
+ }
+ va_end(args);
+ return ret;
+}