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-rw-r--r--lib/cleanup.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/lib/cleanup.c b/lib/cleanup.c
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index 0000000..c16f1bc
--- /dev/null
+++ b/lib/cleanup.c
@@ -0,0 +1,121 @@
+/*
+ * SPDX-FileCopyrightText: 2008 - 2011, Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#include <assert.h>
+#include <stdio.h>
+
+#include "prototypes.h"
+
+/*
+ * The cleanup_functions stack.
+ */
+#define CLEANUP_FUNCTIONS 10
+
+typedef /*@null@*/void * parg_t;
+
+static cleanup_function cleanup_functions[CLEANUP_FUNCTIONS];
+static parg_t cleanup_function_args[CLEANUP_FUNCTIONS];
+static pid_t cleanup_pid = 0;
+
+/*
+ * - Cleanup functions shall not fail.
+ * - You should register do_cleanups with atexit.
+ * - You should add cleanup functions to the stack with add_cleanup when
+ * an operation is expected to be executed later, and remove it from the
+ * stack with del_cleanup when it has been executed.
+ *
+ **/
+
+/*
+ * do_cleanups - perform the actions stored in the cleanup_functions stack.
+ *
+ * Cleanup action are not executed on exit of the processes started by the
+ * parent (first caller of add_cleanup).
+ *
+ * It is intended to be used as:
+ * atexit (do_cleanups);
+ */
+void do_cleanups (void)
+{
+ unsigned int i;
+
+ /* Make sure there were no overflow */
+ assert (NULL == cleanup_functions[CLEANUP_FUNCTIONS-1]);
+
+ if (getpid () != cleanup_pid) {
+ return;
+ }
+
+ i = CLEANUP_FUNCTIONS;
+ do {
+ i--;
+ if (cleanup_functions[i] != NULL) {
+ cleanup_functions[i] (cleanup_function_args[i]);
+ }
+ } while (i>0);
+}
+
+/*
+ * add_cleanup - Add a cleanup_function to the cleanup_functions stack.
+ */
+void add_cleanup (/*@notnull@*/cleanup_function pcf, /*@null@*/void *arg)
+{
+ unsigned int i;
+ assert (NULL != pcf);
+
+ assert (NULL == cleanup_functions[CLEANUP_FUNCTIONS-2]);
+
+ if (0 == cleanup_pid) {
+ cleanup_pid = getpid ();
+ }
+
+ /* Add the cleanup_function at the end of the stack */
+ for (i=0; NULL != cleanup_functions[i]; i++);
+ cleanup_functions[i] = pcf;
+ cleanup_function_args[i] = arg;
+}
+
+/*
+ * del_cleanup - Remove a cleanup_function from the cleanup_functions stack.
+ */
+void del_cleanup (/*@notnull@*/cleanup_function pcf)
+{
+ unsigned int i;
+ assert (NULL != pcf);
+
+ /* Find the pcf cleanup function */
+ for (i=0; i<CLEANUP_FUNCTIONS; i++) {
+ if (cleanup_functions[i] == pcf) {
+ break;
+ }
+ }
+
+ /* Make sure the cleanup function was found */
+ assert (i<CLEANUP_FUNCTIONS);
+
+ /* Move the rest of the cleanup functions */
+ for (; i<CLEANUP_FUNCTIONS; i++) {
+ /* Make sure the cleanup function was specified only once */
+ assert ( (i == (CLEANUP_FUNCTIONS -1))
+ || (cleanup_functions[i+1] != pcf));
+
+ if (i == (CLEANUP_FUNCTIONS -1)) {
+ cleanup_functions[i] = NULL;
+ cleanup_function_args[i] = NULL;
+ } else {
+ cleanup_functions[i] = cleanup_functions[i+1];
+ cleanup_function_args[i] = cleanup_function_args[i+1];
+ }
+
+ /* A NULL indicates the end of the stack */
+ if (NULL == cleanup_functions[i]) {
+ break;
+ }
+ }
+}
+