1 files changed, 87 insertions, 0 deletions
diff --git a/lib/libutil/getlocalbase.c b/lib/libutil/getlocalbase.c
new file mode 100644
index 000000000000..e8aabbab1e14
--- /dev/null
+++ b/lib/libutil/getlocalbase.c
@@ -0,0 +1,87 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright 2020 Stefan Eßer <se@freebsd.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/limits.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <paths.h>
+#include <libutil.h>
+#include <unistd.h>
+
+#ifndef LOCALBASE_PATH
+#define LOCALBASE_PATH _PATH_LOCALBASE
+#endif
+
+#ifndef LOCALBASE_CTL_LEN
+#define LOCALBASE_CTL_LEN MAXPATHLEN
+#endif
+
+/* Any prefix guaranteed to not be the start of a valid path name */
+#define ILLEGAL_PREFIX "/dev/null/"
+
+const char *
+getlocalbase(void)
+{
+#if LOCALBASE_CTL_LEN > 0
+	int localbase_oid[2] = {CTL_USER, USER_LOCALBASE};
+	static char localpath[LOCALBASE_CTL_LEN];
+	size_t localpathlen = LOCALBASE_CTL_LEN;
+#endif
+	char *tmppath;
+	static const char *localbase = NULL;
+
+	if (localbase != NULL)
+		return (localbase);
+
+	if (issetugid() == 0) {
+		tmppath = getenv("LOCALBASE");
+		if (tmppath != NULL && tmppath[0] != '\0') {
+			localbase = tmppath;
+			return (localbase);
+		}
+	}
+
+#if LOCALBASE_CTL_LEN > 0
+	if (sysctl(localbase_oid, 2, localpath, &localpathlen, NULL, 0) != 0) {
+		if (errno != ENOMEM)
+			localbase = LOCALBASE_PATH;
+		else
+			localbase = ILLEGAL_PREFIX;
+	} else {
+		if (localpath[0] != '\0')
+			localbase = localpath;
+		else
+			localbase = LOCALBASE_PATH;
+	}
+#else
+	localbase = LOCALBASE_PATH;
+#endif
+
+	return (localbase);
+}