change charging/discharging to +/- and clean up compiler errors. also clean up todos and optimize a bit. no batteries installed will now output 0% instead of exit. if battery is removed, lowbat will no longer crash

1 files changed, 36 insertions, 27 deletions

diff --git a/lowbat.c b/lowbat.c
index 50651a7..bfdadf2 100644
--- a/lowbat.c
+++ b/lowbat.c
@@ -1,5 +1,5 @@
 /* LINUX DOCS: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power
- * (C) 2024 Tim Keller <tjkeller.xyz>
+ * (C) 2024 Tim Keller <tjk@tjkeller.xyz>
  * MIT License
  */
 
@@ -9,10 +9,11 @@
 #include <unistd.h>
 #include <dirent.h>
 
-#define PERIOD 3 // number of seconds before each check
-#define PSUPATH "/sys/class/power_supply" // number of seconds before each check
+#define PSUPATH "/sys/class/power_supply"
+#define PERIOD            3 // number of seconds before each check
 #define MAX_BATTERIES     8
 #define MAX_PSU_NAME_LEN  8
+#define MAX_MSG_LEN       32
 #define MAX_PROP_PATH_LEN 64
 
 // variables
@@ -28,25 +29,25 @@ void load_installed_batteries() {
 	struct dirent *entry, *subentry;
 
 	if ((dir = opendir(PSUPATH)) == NULL) {
-		fprintf(stderr, "failed to see power supplies"); // TODO
+		fprintf(stderr, "failed to open power supplies filesystem: %s\n", PSUPATH);
 		exit(EXIT_FAILURE);
 	}
 
 	// power supplies TODO warn user if max batteries exceeded
 	num_batteries = 0;
-	while ((entry = readdir(dir)) != NULL && num_batteries < MAX_BATTERIES) {
+	while ((entry = readdir(dir)) != NULL) {
 		if (entry->d_name[0] == '.')
 			continue; // skip . and ..
 		if (strlen(entry->d_name) > MAX_PSU_NAME_LEN) {
-			fprintf(stderr, "the power supply name was too long: %s", entry->d_name);
+			fprintf(stderr, "the power supply's name was too long: %s\n", entry->d_name);
 			exit(EXIT_FAILURE);
 		}
 
 		// power supplies will always be a directory, no need to check beforehand :)
-		snprintf(prop_path, MAX_PROP_PATH_LEN, PSUPATH "/%s", entry->d_name);
+		snprintf(prop_path, MAX_PROP_PATH_LEN, PSUPATH "/%.8s", entry->d_name); // 8 is equal to MAX_PSU_NAME_LEN, prevent compiler warning
 
 		if ((subdir = opendir(prop_path)) == NULL) {
-			fprintf(stderr, "failed to see power supplies sub\n"); // TODO
+			fprintf(stderr, "failed to open power supply: %s\n", prop_path);
 			exit(EXIT_FAILURE);
 		}
 
@@ -54,6 +55,10 @@ void load_installed_batteries() {
 		while ((subentry = readdir(subdir)) != NULL) {
 			// add to list of batteries if it has the status property
 			if (strcmp(subentry->d_name, "status") == 0) {
+ 				if(num_batteries >= MAX_BATTERIES) {
+					fprintf(stderr, "maximum number of batteries (8) exceeded\n");
+					exit(EXIT_FAILURE);
+				}
 				strncpy(batteries[num_batteries], entry->d_name, MAX_PSU_NAME_LEN);
 				num_batteries++;
 				break;
@@ -84,7 +89,7 @@ void read_prop(char *psu, char *prop, char *fmt, void *out) {
 		fclose(fp);
 	}
 	else {
-		printf("failed to read fmt '%s' from property %s\n", fmt, prop_path); // TODO fprintf me plz
+		fprintf(stderr, "failed to read fmt '%s' from property %s\n", fmt, prop_path);
 		exit(EXIT_FAILURE);
 	}
 }
@@ -93,6 +98,9 @@ int get_total_capacity() {
 	unsigned long int energy_full = 0, energy_now = 0, x;
 	int i;
 
+	if (!num_batteries)
+		return 0;
+
 	for (i = 0; i < num_batteries; i++) {
 		read_prop(batteries[i], "energy_full", "%ld", &x);
 		energy_full += x;
@@ -107,6 +115,9 @@ int is_discharging() {
 	char status[12]; // valid values: "Unknown", "Charging", "Discharging", "Not charging", "Full"
 	int i;
 
+	if (!num_batteries)
+		return 0;
+
 	for (i = 0; i < num_batteries; i++) {
 		read_prop(batteries[i], "status", "%s", &status);
 		if (strcmp(status, "Discharging") != 0)
@@ -117,15 +128,9 @@ int is_discharging() {
 }
 
 int main() {
-	int discharging, capacity;
-	int w_lowbat = 0, w_lowbat_crit = 0; // 1 if warned already
-	char msg[32];
-
-	load_installed_batteries();
-	if (!num_batteries) {
-		fprintf(stderr, "no batteries installed in system. exiting...\n"); // TODO
-		exit(EXIT_FAILURE);
-	}
+	int discharging, capacity, old_discharging = -1, old_capacity = -1;
+	int warning_level = 0; // 1 if warned already, 2 if warned with critical warning
+	char msg[MAX_MSG_LEN];
 
 	while (1) {
 		load_installed_batteries();
@@ -133,23 +138,27 @@ int main() {
 		capacity = get_total_capacity();
 
 		if (discharging) {
-			if (capacity <= 5 && !w_lowbat_crit) {
-				sprintf(msg, "%d%% remains", capacity); // TODO snprintf me plz
+			if (capacity <= 5 && warning_level < 2) {
+				snprintf(msg, MAX_MSG_LEN, "%d%% remains", capacity);
 				notifysend("Critical Low Battery Warning", msg, NOTIFY_URGENCY_CRITICAL);
 
-				w_lowbat_crit = w_lowbat = 1;
-			} else if (capacity <= 20 && !w_lowbat) {
-				sprintf(msg, "%d%% remains", capacity);
+				warning_level = 2;
+			} else if (capacity <= 20 && warning_level < 1) {
+				snprintf(msg, MAX_MSG_LEN, "%d%% remains", capacity);
 				notifysend("Low Battery Warning", msg, NOTIFY_URGENCY_NORMAL);
 
-				w_lowbat = 1;
+				warning_level = 1;
 			}
 		} else {
-			w_lowbat_crit = w_lowbat = 0;  // clear conditions
+			warning_level = 0; // clear conditions
 		}
 
-		printf("\r%s %d%%", discharging ? "Discharging" : "Charging", capacity);
-		fflush(stdout);
+		if (discharging != old_discharging || capacity != old_capacity) {
+			printf("\r%s%d%%", discharging ? "-" : "+", capacity);
+			fflush(stdout);
+		}
+		old_discharging = discharging;
+		old_capacity = capacity;
 		sleep(PERIOD);
 	}