[PATCH 2/3] tools lib api fs: Add sysfs__write_int function

From: kan . liang
Date: Thu Mar 23 2017 - 14:37:19 EST


From: Kan Liang <Kan.liang@xxxxxxxxx>

Adding sysfs__write_int function to ease up writing int to sysfs.
New interface is:

int sysfs__write_int(const char *entry, int value);

Also, introducing filename__write_int which is useful for new helpers to
write sysctl values.

Signed-off-by: Kan Liang <Kan.liang@xxxxxxxxx>
---
tools/lib/api/fs/fs.c | 29 +++++++++++++++++++++++++++++
tools/lib/api/fs/fs.h | 4 ++++
2 files changed, 33 insertions(+)

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 809c772..de4f74e 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -387,6 +387,22 @@ int filename__read_str(const char *filename, char **buf, size_t *sizep)
return err;
}

+int filename__write_int(const char *filename, int value)
+{
+ int fd = open(filename, O_WRONLY), err = -1;
+ char buf[64];
+
+ if (fd < 0)
+ return err;
+
+ sprintf(buf, "%d", value);
+ if (write(fd, buf, sizeof(buf)) == sizeof(buf))
+ err = 0;
+
+ close(fd);
+ return err;
+}
+
int procfs__read_str(const char *entry, char **buf, size_t *sizep)
{
char path[PATH_MAX];
@@ -480,3 +496,16 @@ int sysctl__read_int(const char *sysctl, int *value)

return filename__read_int(path, value);
}
+
+int sysfs__write_int(const char *entry, int value)
+{
+ char path[PATH_MAX];
+ const char *sysfs = sysfs__mountpoint();
+
+ if (!sysfs)
+ return -1;
+
+ snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
+
+ return filename__write_int(path, value);
+}
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
index 956c211..4560534 100644
--- a/tools/lib/api/fs/fs.h
+++ b/tools/lib/api/fs/fs.h
@@ -31,6 +31,8 @@ int filename__read_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 filename__write_int(const char *filename, int value);
+
int procfs__read_str(const char *entry, char **buf, size_t *sizep);

int sysctl__read_int(const char *sysctl, int *value);
@@ -38,4 +40,6 @@ int sysfs__read_int(const char *entry, int *value);
int sysfs__read_ull(const char *entry, unsigned long long *value);
int sysfs__read_str(const char *entry, char **buf, size_t *sizep);
int sysfs__read_bool(const char *entry, bool *value);
+
+int sysfs__write_int(const char *entry, int value);
#endif /* __API_FS__ */
--
2.7.4