[PATCH 13/52] perf tools: Add perf_pmu__scan_file()

Adrian Hunter
2014-07-22T13:20:22Z

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>
---
tools/perf/util/pmu.c | 37 +++++++++++++++++++++++++++++++++++++
tools/perf/util/pmu.h | 3 +++
2 files changed, 40 insertions(+)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 11ec977..348d1d2 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 @@ bool pmu_have_event(const char *pname, const char *name)
}
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;
+}
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 281d5b1..c35f578 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -49,6 +49,9 @@ struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu);
void print_pmu_events(const char *event_glob, bool name_only);
bool pmu_have_event(const char *pname, const char *name);

+int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt,
+ ...) __attribute__((format(scanf, 3, 4)));
+
int perf_pmu__test(void);

struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu);
--
1.8.3.2