Initial s390-tools-2.0.0 import

This commit is based on the s390-tools-1.39.0 version. Changes on top of s390-tools-1.39.0: - Add MIT license to all source files - Add LICENSE file - Transform REAMDE to README.md (markdown) - Add AUTHORS.md file - Add CONTRIBUTING.md file - Move changelog from README to CHANGELOG.md file Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
2026-08-05 02:14:52 +00:00 · 2017-08-07 16:13:17 +02:00
commit b627b8d8e1
647 changed files with 168974 additions and 0 deletions
@@ -0,0 +1,94 @@
+/*
+ * dump2tar - tool to dump files and command output into a tar archive
+ *
+ * Reference counting for directory handles
+ *
+ * Copyright IBM Corp. 2016, 2017
+ *
+ * s390-tools is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+
+#include <dirent.h>
+#include <pthread.h>
+#include <sys/types.h>
+
+#include "dref.h"
+#include "global.h"
+#include "misc.h"
+
+/* dref_mutex serializes access to drefs */
+static pthread_mutex_t dref_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static unsigned long num_open_dirs;
+static unsigned long num_open_dirs_max;
+
+/* Lock dref mutex */
+static void dref_lock(void)
+{
+	if (!global_threaded)
+		return;
+	pthread_mutex_lock(&dref_mutex);
+}
+
+/* Unlock dref mutex */
+static void dref_unlock(void)
+{
+	if (!global_threaded)
+		return;
+	pthread_mutex_unlock(&dref_mutex);
+}
+
+/* Create a reference count managed directory handle for @dirname */
+struct dref *dref_create(const char *dirname)
+{
+	struct dref *dref;
+	DIR *dd;
+
+	dd = opendir(dirname);
+	DBG("opendir(%s)=%p (total=%lu)", dirname, dd, ++num_open_dirs);
+	if (!dd) {
+		num_open_dirs--;
+		return NULL;
+	}
+
+	if (num_open_dirs > num_open_dirs_max)
+		num_open_dirs_max = num_open_dirs;
+
+	dref = mmalloc(sizeof(struct dref));
+	dref->dd = dd;
+	dref->dirfd = dirfd(dd);
+	dref->count = 1;
+
+	return dref;
+}
+
+/* Obtain a reference to @dref */
+struct dref *dref_get(struct dref *dref)
+{
+	if (dref) {
+		dref_lock();
+		dref->count++;
+		dref_unlock();
+	}
+
+	return dref;
+}
+
+/* Release a reference to @dref. If this was the last reference, lose the
+ * associated directory handle and free @dref. */
+void dref_put(struct dref *dref)
+{
+	if (dref) {
+		dref_lock();
+		dref->count--;
+		if (dref->count == 0) {
+			num_open_dirs--;
+			DBG("closedir(%p) (total=%lu, max=%lu)", dref->dd,
+			    num_open_dirs, num_open_dirs_max);
+			closedir(dref->dd);
+			free(dref);
+		}
+		dref_unlock();
+	}
+}