Various code cleanups the the xz command line tool.

It now builds with MinGW.

1 files changed, 180 insertions, 0 deletions

diff --git a/src/xz/signals.c b/src/xz/signals.c
new file mode 100644
index 00000000..f19f3f9b
--- /dev/null
+++ b/src/xz/signals.c
@@ -0,0 +1,180 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       signals.c
+/// \brief      Handling signals to abort operation
+//
+//  Copyright (C) 2007-2009 Lasse Collin
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "private.h"
+
+
+volatile sig_atomic_t user_abort = false;
+
+
+#ifndef _WIN32
+
+/// If we were interrupted by a signal, we store the signal number so that
+/// we can raise that signal to kill the program when all cleanups have
+/// been done.
+static volatile sig_atomic_t exit_signal = 0;
+
+/// Mask of signals for which have have established a signal handler to set
+/// user_abort to true.
+static sigset_t hooked_signals;
+
+/// signals_block() and signals_unblock() can be called recursively.
+static size_t signals_block_count = 0;
+
+
+static void
+signal_handler(int sig)
+{
+	exit_signal = sig;
+	user_abort = true;
+	return;
+}
+
+
+extern void
+signals_init(void)
+{
+	// List of signals for which we establish the signal handler.
+	static const int sigs[] = {
+		SIGINT,
+		SIGTERM,
+#ifdef SIGHUP
+		SIGHUP,
+#endif
+#ifdef SIGPIPE
+		SIGPIPE,
+#endif
+#ifdef SIGXCPU
+		SIGXCPU,
+#endif
+#ifdef SIGXFSZ
+		SIGXFSZ,
+#endif
+	};
+
+	// Mask of the signals for which we have established a signal handler.
+	sigemptyset(&hooked_signals);
+	for (size_t i = 0; i < ARRAY_SIZE(sigs); ++i)
+		sigaddset(&hooked_signals, sigs[i]);
+
+	struct sigaction sa;
+
+	// All the signals that we handle we also blocked while the signal
+	// handler runs.
+	sa.sa_mask = hooked_signals;
+
+	// Don't set SA_RESTART, because we want EINTR so that we can check
+	// for user_abort and cleanup before exiting. We block the signals
+	// for which we have established a handler when we don't want EINTR.
+	sa.sa_flags = 0;
+	sa.sa_handler = &signal_handler;
+
+	for (size_t i = 0; i < ARRAY_SIZE(sigs); ++i) {
+		// If the parent process has left some signals ignored,
+		// we don't unignore them.
+		struct sigaction old;
+		if (sigaction(sigs[i], NULL, &old) == 0
+				&& old.sa_handler == SIG_IGN)
+			continue;
+
+		// Establish the signal handler.
+		if (sigaction(sigs[i], &sa, NULL))
+			message_signal_handler();
+	}
+
+	return;
+}
+
+
+extern void
+signals_block(void)
+{
+	if (signals_block_count++ == 0) {
+		const int saved_errno = errno;
+		mythread_sigmask(SIG_BLOCK, &hooked_signals, NULL);
+		errno = saved_errno;
+	}
+
+	return;
+}
+
+
+extern void
+signals_unblock(void)
+{
+	assert(signals_block_count > 0);
+
+	if (--signals_block_count == 0) {
+		const int saved_errno = errno;
+		mythread_sigmask(SIG_UNBLOCK, &hooked_signals, NULL);
+		errno = saved_errno;
+	}
+
+	return;
+}
+
+
+extern void
+signals_exit(void)
+{
+	const int sig = exit_signal;
+
+	if (sig != 0) {
+		struct sigaction sa;
+		sa.sa_handler = SIG_DFL;
+		sigfillset(&sa.sa_mask);
+		sa.sa_flags = 0;
+		sigaction(sig, &sa, NULL);
+		raise(exit_signal);
+	}
+
+	return;
+}
+
+#else
+
+// While Windows has some very basic signal handling functions as required
+// by C89, they are not really used, or so I understood. Instead, we use
+// SetConsoleCtrlHandler() to catch user pressing C-c.
+
+#include <windows.h>
+
+
+static BOOL WINAPI
+signal_handler(DWORD type lzma_attribute((unused)))
+{
+	// Since we don't get a signal number which we could raise() at
+	// signals_exit() like on POSIX, just set the exit status to
+	// indicate an error, so that we cannot return with zero exit status.
+	set_exit_status(E_ERROR);
+	user_abort = true;
+	return TRUE;
+}
+
+
+extern void
+signals_init(void)
+{
+	if (!SetConsoleCtrlHandler(&signal_handler, TRUE))
+		message_signal_handler();
+
+	return;
+}
+
+#endif