1 files changed, 64 insertions, 0 deletions
diff --git a/lib/find_new_sub_uids.c b/lib/find_new_sub_uids.c
new file mode 100644
index 0000000..cc4b0cf
--- /dev/null
+++ b/lib/find_new_sub_uids.c
@@ -0,0 +1,64 @@
+/*
+ * SPDX-FileCopyrightText: 2012 Eric Biederman
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ifdef ENABLE_SUBIDS
+
+#include <assert.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "prototypes.h"
+#include "subordinateio.h"
+#include "getdef.h"
+#include "shadowlog.h"
+
+/*
+ * find_new_sub_uids - Find a new unused range of UIDs.
+ *
+ * If successful, find_new_sub_uids provides a range of unused
+ * user IDs in the [SUB_UID_MIN:SUB_UID_MAX] range.
+ *
+ * Return 0 on success, -1 if no unused UIDs are available.
+ */
+int find_new_sub_uids (uid_t *range_start, unsigned long *range_count)
+{
+	unsigned long min, max;
+	unsigned long count;
+	uid_t start;
+
+	assert (range_start != NULL);
+	assert (range_count != NULL);
+
+	min = getdef_ulong ("SUB_UID_MIN", 100000UL);
+	max = getdef_ulong ("SUB_UID_MAX", 600100000UL);
+	count = getdef_ulong ("SUB_UID_COUNT", 65536);
+
+	if (min > max || count >= max || (min + count - 1) > max) {
+		(void) fprintf (log_get_logfd(),
+				_("%s: Invalid configuration: SUB_UID_MIN (%lu),"
+				  " SUB_UID_MAX (%lu), SUB_UID_COUNT (%lu)\n"),
+			log_get_progname(), min, max, count);
+		return -1;
+	}
+
+	start = sub_uid_find_free_range(min, max, count);
+	if (start == (uid_t)-1) {
+		fprintf (log_get_logfd(),
+		         _("%s: Can't get unique subordinate UID range\n"),
+		         log_get_progname());
+		SYSLOG ((LOG_WARN, "no more available subordinate UIDs on the system"));
+		return -1;
+	}
+	*range_start = start;
+	*range_count = count;
+	return 0;
+}
+#else				/* !ENABLE_SUBIDS */
+extern int ISO_C_forbids_an_empty_translation_unit;
+#endif				/* !ENABLE_SUBIDS */
+