linux-kernel - [PATCH 1/2] tools/lib/api/fs: Add procfs int read/write helpers

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Message-ID: <20170207010917.36ysrh6p7yktxwhc@pd.tnic>
Date:   Tue, 7 Feb 2017 02:09:17 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Robert Richter <rric@...nel.org>,
        Vince Weaver <vince@...ter.net>,
        lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/2] tools/lib/api/fs: Add procfs int read/write helpers

From: Borislav Petkov <bp@...e.de>

Add helper functions to be able to read/write ints into proc files.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 tools/lib/api/fs/fs.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 tools/lib/api/fs/fs.h |  3 +++
 2 files changed, 45 insertions(+)

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 4b6bfc43cccf..8e4b9fe18b75 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -314,6 +314,22 @@ int filename__read_int(const char *filename, int *value)
 	return err;
 }
 
+int filename__write_int(const char *filename, int value)
+{
+	char line[64];
+	int fd = open(filename, O_WRONLY), err = -1;
+
+	if (fd < 0)
+		return -1;
+
+	snprintf(line, sizeof(int), "%d", value);
+
+	err = write(fd, line, strnlen(line, 64));
+
+	close(fd);
+	return err;
+}
+
 /*
  * Parses @value out of @filename with strtoull.
  * By using 0 for base, the strtoull detects the
@@ -400,6 +416,32 @@ int procfs__read_str(const char *entry, char **buf, size_t *sizep)
 	return filename__read_str(path, buf, sizep);
 }
 
+int procfs__read_int(const char *entry, int *value)
+{
+	char path[PATH_MAX];
+	const char *procfs = procfs__mountpoint();
+
+	if (!procfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", procfs, entry);
+
+	return filename__read_int(path, value);
+}
+
+int procfs__write_int(const char *entry, int value)
+{
+	char path[PATH_MAX];
+	const char *procfs = procfs__mountpoint();
+
+	if (!procfs)
+		return -1;
+
+	snprintf(path, sizeof(path), "%s/%s", procfs, entry);
+
+	return filename__write_int(path, value);
+}
+
 int sysfs__read_ull(const char *entry, unsigned long long *value)
 {
 	char path[PATH_MAX];
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
index 6b332dc74498..095f25d4c70f 100644
--- a/tools/lib/api/fs/fs.h
+++ b/tools/lib/api/fs/fs.h
@@ -28,9 +28,12 @@ FS(bpf_fs)
 
 
 int filename__read_int(const char *filename, int *value);
+int filename__write_int(const char *filename, int value);
 int filename__read_ull(const char *filename, unsigned long long *value);
 int filename__read_str(const char *filename, char **buf, size_t *sizep);
 
+int procfs__read_int(const char *entry, int *value);
+int procfs__write_int(const char *entry, int value);
 int procfs__read_str(const char *entry, char **buf, size_t *sizep);
 
 int sysctl__read_int(const char *sysctl, int *value);
-- 
2.11.0


-- 
Regards/Gruss,
    Boris.

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