+
+
+/*
+ * Array of files (full pathnames) to remove on process exit.
+ * Instead of removing slots from the array, just set to NULL
+ * to indicate that the file should no longer be removed.
+ */
+static svector_t exit_filelist = NULL;
+
+/*
+ * Register a file for removal at program termination.
+ */
+static void
+register_for_removal(const char *pathname) {
+ if (exit_filelist == NULL) exit_filelist = svector_create(20);
+ (void) svector_push_back(exit_filelist, add(pathname, NULL));
+}
+
+/*
+ * Unregister all files that were registered to be removed at program
+ * termination. When called with remove_files of 0, this function is
+ * intended for use by one of the programs after a fork(3) without a
+ * subsequent call to one of the exec(3) functions or _exit(3). When
+ * called with non-0 remove_files argument, it is intended for use by
+ * an atexit() function.
+ *
+ * Right after a fork() and before calling exec() or _exit(), if the
+ * child catches one of the appropriate signals, it will remove
+ * all the registered temporary files. Some of those may be needed by
+ * the parent. Some nmh programs ignore or block some of the signals
+ * in the child right after fork(). For the other programs, rather
+ * than complicate things by preventing that, just take the chance
+ * that it might happen. It is harmless to attempt to unlink a
+ * temporary file twice, assuming another one wasn't created too
+ * quickly created with the same name.
+ */
+void
+unregister_for_removal(int remove_files) {
+ if (exit_filelist) {
+ size_t i;
+
+ for (i = 0; i < svector_size(exit_filelist); ++i) {
+ char *filename = svector_at(exit_filelist, i);
+
+ if (filename) {
+ if (remove_files) (void) unlink(filename);
+ free(filename);
+ }
+ }
+
+ svector_free(exit_filelist);
+ exit_filelist = NULL;
+ }
+}
+
+/*
+ * If the file was registered for removal, deregister it. In
+ * any case, unlink it.
+ */
+int
+m_unlink(const char *pathname) {
+ if (exit_filelist) {
+ char **slot = svector_find(exit_filelist, pathname);
+
+ if (slot && *slot) {
+ free(*slot);
+ *slot = NULL;
+ }
+ }
+
+ return unlink(pathname);
+ /* errno should be set to ENOENT if file was not found */
+}
+
+/*
+ * Remove all registered temporary files.
+ */
+void
+remove_registered_files_atexit() {
+ unregister_for_removal(1);
+}
+
+/*
+ * Remove all registered temporary files. Suitable for use as a
+ * signal handler. If the signal is one of the usual process
+ * termination signals, calls exit(). Otherwise, disables itself
+ * by restoring the default action and then re-raises the signal,
+ * in case the use was expecting a core dump.
+ */
+void
+remove_registered_files(int sig) {
+ struct sigaction act;
+
+ /*
+ * Ignore this signal for the duration. And we either exit() or
+ * disable this signal handler below, so don't restore this handler.
+ */
+ act.sa_handler = SIG_IGN;
+ (void) sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ (void) sigaction(sig, &act, 0);
+
+ if (sig == SIGHUP || sig == SIGINT || sig == SIGQUIT || sig == SIGTERM) {
+ /*
+ * We don't need to call remove_registered_files_atexit() if
+ * it was registered with atexit(), but let's not assume that.
+ * It's harmless to call it twice.
+ */
+ remove_registered_files_atexit();
+
+ exit(1);
+ } else {
+ act.sa_handler = SIG_DFL;
+ (void) sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ (void) sigaction(sig, &act, 0);
+
+ remove_registered_files_atexit();
+
+ (void) raise(sig);
+ }
+}
projects / nmh / commitdiff