1 files changed, 71 insertions, 0 deletions
diff --git a/src/shared/sysctl-util.c b/src/shared/sysctl-util.c
new file mode 100644
index 0000000..480e6c3
--- /dev/null
+++ b/src/shared/sysctl-util.c
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "fd-util.h"
+#include "fileio.h"
+#include "log.h"
+#include "macro.h"
+#include "string-util.h"
+#include "sysctl-util.h"
+
+char *sysctl_normalize(char *s) {
+        char *n;
+
+        n = strpbrk(s, "/.");
+        /* If the first separator is a slash, the path is
+         * assumed to be normalized and slashes remain slashes
+         * and dots remains dots. */
+        if (!n || *n == '/')
+                return s;
+
+        /* Otherwise, dots become slashes and slashes become
+         * dots. Fun. */
+        while (n) {
+                if (*n == '.')
+                        *n = '/';
+                else
+                        *n = '.';
+
+                n = strpbrk(n + 1, "/.");
+        }
+
+        return s;
+}
+
+int sysctl_write(const char *property, const char *value) {
+        char *p;
+        _cleanup_close_ int fd = -1;
+
+        assert(property);
+        assert(value);
+
+        log_debug("Setting '%s' to '%.*s'.", property, (int) strcspn(value, NEWLINE), value);
+
+        p = strjoina("/proc/sys/", property);
+        fd = open(p, O_WRONLY|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        if (!endswith(value, "\n"))
+                value = strjoina(value, "\n");
+
+        if (write(fd, value, strlen(value)) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int sysctl_read(const char *property, char **content) {
+        char *p;
+
+        assert(property);
+        assert(content);
+
+        p = strjoina("/proc/sys/", property);
+        return read_full_file(p, content, NULL);
+}