move signal handlers to sighandler.[ch]

Signals are special because they run asynchronously, making them
non-trivial to handle correctly.  Move the handlers a separate file to
offset them from the normal code and make them easier to separate into
individual functions without further cluttering pacman.c

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

src/pacman/Makefile.am

@@ -40,6 +40,7 @@ pacman_SOURCES = \
 	pacman.h pacman.c \
 	query.c \
 	remove.c \
+	sighandler.h sighandler.c \
 	sync.c \
 	callback.h callback.c \
 	upgrade.c \

src/pacman/pacman.c

@@ -30,7 +30,6 @@
 #include <limits.h>
 #include <getopt.h>
 #include <string.h>
-#include <signal.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/utsname.h> /* uname */
@@ -45,6 +44,7 @@
 #include "pacman.h"
 #include "util.h"
 #include "conf.h"
+#include "sighandler.h"
 
 /* list of targets specified on command line */
 static alpm_list_t *pm_targets;
@@ -294,51 +294,6 @@ static void cleanup(int ret)
 	exit(ret);
 }
 
-/** Write function that correctly handles EINTR.
- */
-static ssize_t xwrite(int fd, const void *buf, size_t count)
-{
-	ssize_t ret;
-	do {
-		ret = write(fd, buf, count);
-	} while(ret == -1 && errno == EINTR);
-	return ret;
-}
-
-/** Catches thrown signals. Performs necessary cleanup to ensure database is
- * in a consistent state.
- * @param signum the thrown signal
- */
-static void handler(int signum)
-{
-	if(signum == SIGSEGV) {
-		const char msg[] = "\nerror: segmentation fault\n"
-			"Please submit a full bug report with --debug if appropriate.\n";
-		xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
-		exit(signum);
-	} else if(signum == SIGINT || signum == SIGHUP) {
-		if(signum == SIGINT) {
-			const char msg[] = "\nInterrupt signal received\n";
-			xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
-		} else {
-			const char msg[] = "\nHangup signal received\n";
-			xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
-		}
-		if(alpm_trans_interrupt(config->handle) == 0) {
-			/* a transaction is being interrupted, don't exit pacman yet. */
-			return;
-		}
-	} else if(signum == SIGWINCH) {
-		columns_cache_reset();
-		return;
-	}
-	/* SIGINT/SIGHUP: no committing transaction, release it now and then exit pacman */
-	alpm_unlock(config->handle);
-	/* output a newline to be sure we clear any line we may be on */
-	xwrite(STDOUT_FILENO, "\n", 1);
-	_Exit(128 + signum);
-}
-
 static void invalid_opt(int used, const char *opt1, const char *opt2)
 {
 	if(used) {
@@ -1134,20 +1089,9 @@ int main(int argc, char *argv[])
 {
 	int ret = 0;
 	size_t i;
-	struct sigaction new_action;
-	const int signals[] = { SIGHUP, SIGINT, SIGSEGV, SIGWINCH };
 	uid_t myuid = getuid();
 
-	/* Set signal handlers */
+	install_signal_handlers();
-	/* Set up the structure to specify the new action. */
-	new_action.sa_handler = handler;
-	sigemptyset(&new_action.sa_mask);
-	new_action.sa_flags = SA_RESTART;
-
-	/* assign our handler to any signals we care about */
-	for(i = 0; i < ARRAYSIZE(signals); i++) {
-		sigaction(signals[i], &new_action, NULL);
-	}
 
 	/* i18n init */
 #if defined(ENABLE_NLS)

src/pacman/sighandler.c

@@ -0,0 +1,92 @@
+/*
+ *  sighandler.c
+ *
+ *  Copyright (c) 2015 Pacman Development Team <pacman-dev@archlinux.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include <alpm.h>
+
+#include "conf.h"
+#include "sighandler.h"
+#include "util.h"
+
+/** Write function that correctly handles EINTR.
+ */
+static ssize_t xwrite(int fd, const void *buf, size_t count)
+{
+	ssize_t ret;
+	do {
+		ret = write(fd, buf, count);
+	} while(ret == -1 && errno == EINTR);
+	return ret;
+}
+
+/** Catches thrown signals. Performs necessary cleanup to ensure database is
+ * in a consistent state.
+ * @param signum the thrown signal
+ */
+static void handler(int signum)
+{
+	if(signum == SIGSEGV) {
+		const char msg[] = "\nerror: segmentation fault\n"
+			"Please submit a full bug report with --debug if appropriate.\n";
+		xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
+		exit(signum);
+	} else if(signum == SIGINT || signum == SIGHUP) {
+		if(signum == SIGINT) {
+			const char msg[] = "\nInterrupt signal received\n";
+			xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
+		} else {
+			const char msg[] = "\nHangup signal received\n";
+			xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
+		}
+		if(alpm_trans_interrupt(config->handle) == 0) {
+			/* a transaction is being interrupted, don't exit pacman yet. */
+			return;
+		}
+	} else if(signum == SIGWINCH) {
+		columns_cache_reset();
+		return;
+	}
+	/* SIGINT/SIGHUP: no committing transaction, release it now and then exit pacman */
+	alpm_unlock(config->handle);
+	/* output a newline to be sure we clear any line we may be on */
+	xwrite(STDOUT_FILENO, "\n", 1);
+	_Exit(128 + signum);
+}
+
+void install_signal_handlers(void)
+{
+	struct sigaction new_action;
+	const int signals[] = { SIGHUP, SIGINT, SIGSEGV, SIGWINCH };
+	size_t i;
+	/* Set signal handlers */
+	/* Set up the structure to specify the new action. */
+	new_action.sa_handler = handler;
+	sigemptyset(&new_action.sa_mask);
+	new_action.sa_flags = SA_RESTART;
+
+	/* assign our handler to any signals we care about */
+	for(i = 0; i < ARRAYSIZE(signals); i++) {
+		sigaction(signals[i], &new_action, NULL);
+	}
+}
+
+/* vim: set noet: */

src/pacman/sighandler.h

@@ -0,0 +1,27 @@
+/*
+ *  sighandler.h
+ *
+ *  Copyright (c) 2015 Pacman Development Team <pacman-dev@archlinux.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _PM_SIGHANDLER_H
+#define _PM_SIGHANDLER_H
+
+void install_signal_handlers(void);
+
+#endif /* _PM_SIGHANDLER_H */
+
+/* vim: set noet: */