From 53a906bd9801d1b5e62796f5ce3ba160c7bdae07 Mon Sep 17 00:00:00 2001
From: Antoine Damhet <antoine.damhet@lse.epita.fr>
Date: Tue, 10 Sep 2019 08:52:59 +0200
Subject: Make the use of `SetBrightness` dynamic

It will only be used if the user do not have the permission to directly
write to the backlight device.

Signed-off-by: Antoine Damhet <antoine.damhet@lse.epita.fr>
---
 brightnessctl.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/brightnessctl.c b/brightnessctl.c
index 77dca5c..680dc4b 100644
--- a/brightnessctl.c
+++ b/brightnessctl.c
@@ -38,7 +38,7 @@ static char *class_path(char *);
 static void apply_value(struct device *, struct value *);
 static int apply_operation(struct device *, enum operation, struct value *);
 static bool parse_value(struct value *, char *);
-static bool write_device(struct device *);
+static bool do_write_device(struct device *);
 static bool read_device(struct device *, char *, char *);
 static int read_class(struct device **, char *);
 static int read_devices(struct device **);
@@ -50,6 +50,10 @@ static bool restore_device_data(struct device *);
 static bool ensure_dir(char *);
 #define ensure_run_dir() ensure_dir(run_dir)
 
+#ifdef ENABLE_SYSTEMD
+static bool logind_set_brightness(struct device *);
+#endif
+
 struct device {
 	char *class;
 	char *id;
@@ -103,16 +107,13 @@ static const struct option options[] = {
 	{NULL,}
 };
 
+static bool (*write_device)(struct device *) = do_write_device;
+
 int main(int argc, char **argv) {
 	struct device *devs[255];
 	struct device *dev;
 	struct utsname name;
-	char *dev_name, *sys_run_dir;
-
-#ifndef ENABLE_SYSTEMD
-	char *file_path;
-#endif
-
+	char *dev_name, *file_path, *sys_run_dir;
 	int n, c, phelp = 0;
 	if (uname(&name))
 		fail("Unable to determine current OS. Exiting!\n");
@@ -212,20 +213,20 @@ int main(int argc, char **argv) {
 		fail("Invalid value given");
 	if (!(dev = find_device(devs, dev_name)))
 		fail("Device '%s' not found.\n", dev_name);
-
-#ifndef ENABLE_SYSTEMD
 	if ((p.operation == SET || p.restore) && !p.pretend && geteuid()) {
 		errno = 0;
 		file_path = cat_with('/', path, dev->class, dev->id, "brightness");
 		if (access(file_path, W_OK)) {
+#ifdef ENABLE_SYSTEMD
+			write_device = logind_set_brightness;
+#else
 			perror("Can't modify brightness");
 			fail("\nYou should run this program with root privileges.\n"
 				"Alternatively, get write permissions for device files.\n");
+#endif
 		}
 		free(file_path);
 	}
-#endif
-
 	if ((sys_run_dir = getenv("XDG_RUNTIME_DIR")))
 		run_dir = dir_child(sys_run_dir, "brightnessctl");
 	if (p.save)
@@ -366,7 +367,7 @@ apply:
 
 #ifdef ENABLE_SYSTEMD
 
-bool write_device(struct device *d) {
+bool logind_set_brightness(struct device *d) {
 	sd_bus *bus = NULL;
 	int r = sd_bus_default_system(&bus);
 	if (r < 0) {
@@ -393,9 +394,9 @@ bool write_device(struct device *d) {
 	return r >= 0;
 }
 
-#else
+#endif
 
-bool write_device(struct device *d) {
+bool do_write_device(struct device *d) {
 	FILE *f;
 	char c[16];
 	size_t s = sprintf(c, "%u", d->curr_brightness);
@@ -418,8 +419,6 @@ fail:
 	return !errno;
 }
 
-#endif
-
 bool read_device(struct device *d, char *class, char *id) {
 	DIR *dirp;
 	FILE *f;
-- 
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