initial commit

1 files changed, 155 insertions, 0 deletions

diff --git a/lowbat.c b/lowbat.c
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+++ b/lowbat.c
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+/* LINUX DOCS: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power
+ * (C) 2024 Tim Keller <tjkeller.xyz>
+ * MIT License
+ */
+
+#include <libnotify/notify.h>
+#include <stdio.h>
+#include <stdlib.h>
+#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 MAX_BATTERIES     8
+#define MAX_PSU_NAME_LEN  8
+#define MAX_PROP_PATH_LEN 64
+
+// variables
+static char batteries[MAX_BATTERIES][MAX_PSU_NAME_LEN];
+static unsigned int num_batteries;
+static FILE *fp;
+static char prop_path[MAX_PROP_PATH_LEN];
+
+// functions
+void load_installed_batteries() {
+	// search through "power supplies" for "status" property (only available on batteries)
+	DIR *dir, *subdir;
+	struct dirent *entry, *subentry;
+
+	if ((dir = opendir(PSUPATH)) == NULL) {
+		fprintf(stderr, "failed to see power supplies"); // TODO
+		exit(EXIT_FAILURE);
+	}
+
+	// power supplies TODO warn user if max batteries exceeded
+	num_batteries = 0;
+	while ((entry = readdir(dir)) != NULL && num_batteries < MAX_BATTERIES) {
+		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);
+			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);
+
+		if ((subdir = opendir(prop_path)) == NULL) {
+			fprintf(stderr, "failed to see power supplies sub\n"); // TODO
+			exit(EXIT_FAILURE);
+		}
+
+		// power supply properties
+		while ((subentry = readdir(subdir)) != NULL) {
+			// add to list of batteries if it has the status property
+			if (strcmp(subentry->d_name, "status") == 0) {
+				strncpy(batteries[num_batteries], entry->d_name, MAX_PSU_NAME_LEN);
+				num_batteries++;
+				break;
+			}
+		}
+		closedir(subdir);
+	}
+	closedir(dir);
+}
+
+void notifysend(char *title, char *content) {
+	NotifyNotification *notif;
+	notify_init("lowbat");
+	notif = notify_notification_new(title, content, NULL);
+
+	notify_notification_show(notif, NULL);
+}
+
+void read_prop(char *psu, char *prop, char *fmt, void *out) {
+	/* this function is only designed to read one var at a time because all bat
+	 * properties will only be one var */
+	snprintf(prop_path, MAX_PROP_PATH_LEN, PSUPATH "/%s/%s", psu, prop);
+
+	if ((fp = fopen(prop_path, "r")) != NULL) {
+		fscanf(fp, fmt, out);
+		fclose(fp);
+	}
+	else {
+		printf("failed to read fmt '%s' from property %s\n", fmt, prop_path); // TODO fprintf me plz
+		exit(EXIT_FAILURE);
+	}
+}
+
+int get_total_capacity() {
+	unsigned long int energy_full = 0, energy_now = 0, x;
+	int i;
+
+	for (i = 0; i < num_batteries; i++) {
+		read_prop(batteries[i], "energy_full", "%ld", &x);
+		energy_full += x;
+		read_prop(batteries[i], "energy_now",  "%ld", &x);
+		energy_now += x;
+	}
+
+	return energy_now * 100 / energy_full;
+}
+
+int is_discharging() {
+	char status[12]; // valid values: "Unknown", "Charging", "Discharging", "Not charging", "Full"
+	int i;
+
+	for (i = 0; i < num_batteries; i++) {
+		read_prop(batteries[i], "status", "%s", &status);
+		if (strcmp(status, "Discharging") != 0)
+			return 0;
+	}
+
+	return 1;
+}
+
+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);
+	}
+
+	while (1) {
+		load_installed_batteries();
+		discharging = is_discharging();
+		capacity = get_total_capacity();
+
+		if (discharging) {
+			if (capacity <= 5 && !w_lowbat_crit) {
+				sprintf(msg, "%d%% remains", capacity); // TODO snprintf me plz
+				notifysend("Critical Low Battery Warning", msg);
+
+				w_lowbat_crit = w_lowbat = 1;
+			} else if (capacity <= 20 && !w_lowbat) {
+				sprintf(msg, "%d%% remains", capacity);
+				notifysend("Low Battery Warning", msg);
+
+				w_lowbat = 1;
+			}
+		} else {
+			w_lowbat_crit = w_lowbat = 0;  // clear conditions
+		}
+
+		printf("\r%d%%", capacity);
+		fflush(stdout);
+		sleep(PERIOD);
+	}
+
+	return 0;
+}