sysctl: Add sysctl module with /proc/sys helpers

Moved sysctl get/set funcs from flowtop to separated sysctl module.

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 67 insertions, 0 deletions

diff --git a/sysctl.c b/sysctl.c
new file mode 100644
index 0000000..283d403
--- /dev/null
+++ b/sysctl.c
@@ -0,0 +1,67 @@
+/*
+ * sysctl - sysctl set/get helpers
+ * Subject to the GPL, version 2.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/limits.h>
+
+#include "built_in.h"
+
+#define SYS_PATH "/proc/sys/"
+
+int sysctl_set_int(const char *file, int value)
+{
+	char path[PATH_MAX];
+	char str[64];
+	ssize_t ret;
+	int fd;
+
+	strncpy(path, SYS_PATH, PATH_MAX);
+	strncat(path, file, PATH_MAX - sizeof(SYS_PATH) - 1);
+
+	fd = open(path, O_WRONLY);
+	if (unlikely(fd < 0))
+		return -1;
+
+	ret = snprintf(str, 63, "%d", value);
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+
+	ret = write(fd, str, strlen(str));
+
+	close(fd);
+	return ret <= 0 ? -1 : 0;
+}
+
+int sysctl_get_int(const char *file, int *value)
+{
+	char path[PATH_MAX];
+	char str[64];
+	ssize_t ret;
+	int fd;
+
+	strncpy(path, SYS_PATH, PATH_MAX);
+	strncat(path, file, PATH_MAX - sizeof(SYS_PATH) - 1);
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	ret = read(fd, str, sizeof(str));
+	if (ret > 0) {
+		*value = atoi(str);
+		ret = 0;
+	} else {
+		ret = -1;
+	}
+
+	close(fd);
+	return ret;
+}