Merge branch 'hooks-dir'

6 files changed, 190 insertions, 8 deletions

diff --git a/redshift.1 b/redshift.1
index 3cd9184..c9667aa 100644
--- a/redshift.1
+++ b/redshift.1
@@ -148,6 +148,25 @@ location\-provider=manual
 lat=55.7
 lon=12.6
 .fi
+.SH HOOKS
+Executable files (e.g. scripts) placed in `~/.config/redshift/hooks'
+will be run when a certain event happens. The first parameter to the
+script indicates the event and further parameters may indicate
+more details about the event. The event `period-changed' is indicated
+when the period changes (`night', `daytime', `transition'). The second
+parameter is the old period and the third is the new period. The event
+is also signaled when Redshift starts up with the old period set to
+`none'.
+
+A simple script to handle these events can be written like this:
+.IP
+.nf
+#!/bin/sh
+case \fB$1\fR in
+    \fBperiod-changed\fR)
+        exec notify-send "Redshift" "Period changed to \fB$3\fR"
+esac
+.fi
 .SH AUTHOR
 .B redshift
 was written by Jon Lund Steffensen <jonlst@gmail.com>.
diff --git a/src/Makefile.am b/src/Makefile.am
index 8d11a03..c7a5444 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,6 +15,7 @@ redshift_SOURCES = \
 	location-manual.c location-manual.h \
 	solar.c solar.h \
 	systemtime.c systemtime.h \
+	hooks.c hooks.h \
 	gamma-dummy.c gamma-dummy.h
 
 EXTRA_redshift_SOURCES = \
diff --git a/src/hooks.c b/src/hooks.c
new file mode 100644
index 0000000..d051c4b
--- /dev/null
+++ b/src/hooks.c
@@ -0,0 +1,113 @@
+/* hooks.c -- Hooks triggered by events
+   This file is part of Redshift.
+
+   Redshift 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 3 of the License, or
+   (at your option) any later version.
+
+   Redshift 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 Redshift.  If not, see <http://www.gnu.org/licenses/>.
+
+   Copyright (c) 2014  Jon Lund Steffensen <jonlst@gmail.com>
+*/
+
+#include <stdlib.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <errno.h>
+#ifndef _WIN32
+# include <pwd.h>
+#endif
+
+#include "hooks.h"
+#include "redshift.h"
+
+#define MAX_HOOK_PATH  4096
+
+
+/* Names of periods supplied to scripts. */
+static const char *period_names[] = {
+	"none",
+	"daytime",
+	"night",
+	"transition"
+};
+
+
+/* Try to open the directory containing hooks. HP is a string
+   of MAX_HOOK_PATH length that will be filled with the path
+   of the returned directory. */
+static DIR *
+open_hooks_dir(char *hp)
+{
+	char *env;
+
+	if ((env = getenv("XDG_CONFIG_HOME")) != NULL &&
+	    env[0] != '\0') {
+		snprintf(hp, MAX_HOOK_PATH, "%s/redshift/hooks", env);
+		return opendir(hp);
+	}
+
+	if ((env = getenv("HOME")) != NULL &&
+	    env[0] != '\0') {
+		snprintf(hp, MAX_HOOK_PATH, "%s/.config/redshift/hooks", env);
+		return opendir(hp);
+	}
+
+#ifndef _WIN32
+	struct passwd *pwd = getpwuid(getuid());
+	snprintf(hp, MAX_HOOK_PATH, "%s/.config/redshift/hooks", pwd->pw_dir);
+	return opendir(hp);
+#else
+	return NULL;
+#endif
+}
+
+/* Run hooks with a signal that the period changed. */
+void
+hooks_signal_period_change(period_t prev_period, period_t period)
+{
+	char hooksdir_path[MAX_HOOK_PATH];
+	DIR *hooks_dir = open_hooks_dir(hooksdir_path);
+	if (hooks_dir == NULL) return;
+
+	struct dirent* ent;
+	while ((ent = readdir(hooks_dir)) != NULL) {
+		/* Skip hidden and special files (., ..) */
+		if (ent->d_name[0] == '\0' || ent->d_name[0] == '.') continue;
+
+		char *hook_name = ent->d_name;
+		char hook_path[MAX_HOOK_PATH];
+		snprintf(hook_path, sizeof(hook_path), "%s/%s",
+			 hooksdir_path, hook_name);
+
+#ifndef _WIN32
+		/* Fork and exec the hook. We close stdout
+		   so the hook cannot interfere with the normal
+		   output. */
+		pid_t pid = fork();
+		if (pid == (pid_t)-1) {
+			perror("fork");
+			continue;
+		} else if (pid == 0) { /* Child */
+			close(STDOUT_FILENO);
+
+			int r = execl(hook_path, hook_name,
+				      "period-changed",
+				      period_names[prev_period],
+				      period_names[period], NULL);
+			if (r < 0 && errno != EACCES) perror("execl");
+
+			/* Only reached on error */
+			_exit(EXIT_FAILURE);
+		}
+#endif
+	}
+}
diff --git a/src/hooks.h b/src/hooks.h
new file mode 100644
index 0000000..fd1c2f0
--- /dev/null
+++ b/src/hooks.h
@@ -0,0 +1,29 @@
+/* hooks.h -- Hooks triggered by events
+   This file is part of Redshift.
+
+   Redshift 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 3 of the License, or
+   (at your option) any later version.
+
+   Redshift 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 Redshift.  If not, see <http://www.gnu.org/licenses/>.
+
+   Copyright (c) 2014  Jon Lund Steffensen <jonlst@gmail.com>
+*/
+
+#ifndef REDSHIFT_HOOKS_H
+#define REDSHIFT_HOOKS_H
+
+#include "redshift.h"
+
+void hooks_signal_period_change(period_t prev_period,
+				period_t period);
+
+
+#endif /* ! REDSHIFT_HOOKS_H */
diff --git a/src/redshift.c b/src/redshift.c
index 60cd9f5..429ae38 100644
--- a/src/redshift.c
+++ b/src/redshift.c
@@ -47,6 +47,7 @@
 #include "config-ini.h"
 #include "solar.h"
 #include "systemtime.h"
+#include "hooks.h"
 
 
 #define MIN(x,y)  ((x) < (y) ? (x) : (y))
@@ -296,14 +297,6 @@ typedef enum {
 	PROGRAM_MODE_MANUAL
 } program_mode_t;
 
-/* Periods of day. */
-typedef enum {
-	PERIOD_NONE = 0,
-	PERIOD_DAYTIME,
-	PERIOD_NIGHT,
-	PERIOD_TRANSITION
-} period_t;
-
 /* Names of periods of day */
 static const char *period_names[] = {
 	/* TRANSLATORS: Name printed when period of day is unknown */
@@ -1445,6 +1438,18 @@ main(int argc, char *argv[])
 			perror("sigaction");
 			exit(EXIT_FAILURE);
 		}
+
+		/* Ignore CHLD signal. This causes child processes
+		   (hooks) to be reaped automatically. */
+		sigact.sa_handler = SIG_IGN;
+		sigact.sa_mask = sigset;
+		sigact.sa_flags = 0;
+
+		r = sigaction(SIGCHLD, &sigact, NULL);
+		if (r < 0) {
+			perror("sigaction");
+			exit(EXIT_FAILURE);
+		}
 #endif /* HAVE_SIGNAL_H && ! __WIN32__ */
 
 		if (verbose) {
@@ -1540,6 +1545,12 @@ main(int argc, char *argv[])
 				print_period(period, transition);
 			}
 
+			/* Activate hooks if period changed */
+			if (period != prev_period) {
+				hooks_signal_period_change(prev_period,
+							   period);
+			}
+
 			/* Ongoing short transition */
 			if (short_trans_delta) {
 				/* Calculate alpha */
diff --git a/src/redshift.h b/src/redshift.h
index e8be4e6..5f4335c 100644
--- a/src/redshift.h
+++ b/src/redshift.h
@@ -24,6 +24,15 @@
 #include <stdlib.h>
 
 
+/* Periods of day. */
+typedef enum {
+	PERIOD_NONE = 0,
+	PERIOD_DAYTIME,
+	PERIOD_NIGHT,
+	PERIOD_TRANSITION
+} period_t;
+
+
 /* Color setting */
 typedef struct {
 	int temperature;