add more info about configuring event-handler

There's still memory being leaked by the wayland stuff

README.md

@@ -3,13 +3,32 @@ My custom event handler for battery related things. Here's a brief rundown of
 all the features:
 
 When the percentage gets below a specified percentage it will blink the
-specified led at any rate defined by the config file.
+specified led at any rate defined by the config file. Example:
+![blink.mp4](./examples/blink.mp4 "blink.mp4")
 
 If the system is plugged in and a wayland session is running then the event
 handler will place an idle inhibitor on the session to keep the computer from
 going to sleep. The inhibitor is removed when the system is unplugged.
 
-## Default Config
+> [!WARNING]
+> event-handler relies on [acpid](https://wiki.archlinux.org/title/Acpid) to
+> monitor battery events ensure you have it installed and running before using
+> event-handler
+
+## Configuring
+I built event-handler to be used as a service independent of my current user
+and such event-handler does not read the configuration file from any default
+path. Instead it's up to you to choose where it is and pass the file's full
+path into event-handler like so:
+```bash
+eh -c ./config.toml
+```
+
+The config is completely optional, however you will most likely need it as the
+default is setup for my framework 13 system running Void Linux. Below are the
+defaults:
+
+### Default Config
 ```toml
 [battery]
 status_path = "/sys/class/power_supply/BAT1"
@@ -25,3 +44,8 @@ timing_formula = "1.7 + 18.5 * exp(-0.29 * p)" # p is the percentage of the batt
 [acpi_daemon]
 socket_path = "/run/acpid.socket"
 ```
+
+> [!NOTE]
+> The default formula may or may not work above 15 percent due to led
+> shenanigans. If you wish to craft your own formula all relevant notation may
+> be found in [this repo](https://github.com/codeplea/tinyexpr).

src/battery.c

@@ -3,6 +3,7 @@
 #include <stdbool.h>
 #include <unistd.h>
 
+#include "log.h"
 #include "utils.h"
 
 #include "config.h"
@@ -17,6 +18,11 @@ char
   /* open up the battery capacity for reading */
   d = concat(battery_status_path, "/capacity");
   f = fopen(d, "r");
+  if (!f) {
+    log_fatal("battery directory does not exist");
+    free(d);
+    return NULL;
+  }
   free(d);
 
   /* create enough space for the battery percentage */

src/config.c

@@ -49,15 +49,12 @@ led_blink_timing_func(int percent)
 {
 	percentage = percent;
 	return te_eval(expr);
-
-  // return 1.7 + 18.5 * exp(-0.29 * percent);
 }
 
 static void
 free_eval(int sig)
 {
 	te_free(expr);
-	exit(sig);
 }
 
 void
@@ -67,13 +64,13 @@ setup_led_formula(void)
 
 	te_variable vars[] = { { "p", &percentage } };
 	expr = te_compile(led_blink_timing_formula, vars, 1, &err);
-	signal(SIGINT, free_eval);
 	if (!expr) {
 		log_fatal("%s", led_blink_timing_formula);
 		log_fatal("%*s^ Error near here", err - 1, "");
 
 		exit(1);
 	}
+	signal(SIGINT, free_eval);
 }
 
 void
@@ -86,6 +83,7 @@ parse_config_file(char *path)
 	f = fopen(path, "r");
 	if (!f) {
 		log_fatal("Failed to open config file: %s", path);
+    return;
 	}
 
 	config = toml_parse_file(f, errbuf, sizeof(errbuf));
@@ -106,4 +104,6 @@ parse_config_file(char *path)
 	set_int_conf(led_blink_trigger_level, led_blink, "power_source");
 	set_str_conf(led_blink_timing_formula, led_blink, "timing_formula");
 	set_str_conf(acpi_daemon_socket_path, acpi_daemon, "socket_path");
+
+  toml_free(config);
 }

src/led.c

@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/poll.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include "led.h"
@@ -114,8 +115,6 @@ pre_exit(int signal)
   fclose(data->pfile);
   free(data->file_name);
   free(data);
-
-  exit(0);
 }
 
 int
@@ -124,6 +123,13 @@ led_create_thread(char *file)
   int err;
   struct sigaction act;
   static bool running;
+  struct stat s;
+
+  /* ensure that file exists */
+  err = stat(file, &s);
+  if (err < 0 || !S_ISREG(s.st_mode)) {
+    return 2;
+  }
 
   /* make sure the led thread cannot be created twice */
   if (running) {

src/main.c

@@ -23,7 +23,13 @@
 #include "config.h"
 
 #define MAX_BUFLEN 1024
+#define wrap(ok, func) do { \
+    if (ok) {               \
+      func;                 \
+    }                       \
+  } while (0)
 
+bool led_ok, wayland_ok;
 static struct cag_option options[] = {
 	{
 		.identifier = 'c',
@@ -51,6 +57,7 @@ on_battery_event(char *percent, bool plugged)
     /* convert battery percentage to an int */
     res = strtol(percent, &ep, 10);
 
+    wrap(led_ok,
       if (res <= led_blink_trigger_level) {
         rate = led_blink_timing_func(res);
         if (rate >= 1) {
@@ -59,11 +66,12 @@ on_battery_event(char *percent, bool plugged)
       } else {
         led_set_rate(0);
       }
+    );
 
-		wayland_set_idle_lock(false);
+		wrap(wayland_ok, wayland_set_idle_lock(false));
   } else {
-    led_set_rate(0);
+    wrap(led_ok, led_set_rate(0));
-		wayland_set_idle_lock(true);
+		wrap(wayland_ok, wayland_set_idle_lock(true));
   }
 
   free(percent);
@@ -74,9 +82,12 @@ main(int argc, char *argv[])
 {
   cag_option_context context;
   bool plugged = plugged_in(battery_power_source);
-  char buffer[MAX_BUFLEN], *out[4], *config_path;
+  char buffer[MAX_BUFLEN], *out[4], *config_path, *percent;
   int sock_fd;
 
+  /* defaults to working */
+  led_ok = wayland_ok = true;
+
   cag_option_init(&context, options, CAG_ARRAY_SIZE(options), argc, argv);
   while (cag_option_fetch(&context)) {
 		switch (cag_option_get_identifier(&context)) {
@@ -104,15 +115,22 @@ main(int argc, char *argv[])
   sock_fd = acpi_create_socket(acpi_daemon_socket_path);
 
   /* create the led thread */
-  led_create_thread(led_brightness_path);
+  if (led_create_thread(led_brightness_path)) {
+    led_ok = false;
+  }
 
 	/* create the wayland thread */
-  wayland_create_thread();
+  if (wayland_create_thread()) {
+    wayland_ok = false;
+  }
 
   /* run events that need to be run on start to ensure that the current state
    * inside the program reflects that that is outside the program
    */
-  on_battery_event(battery_percent(), plugged);
+  percent = battery_percent();
+  if (percent == NULL) {
+    on_battery_event(percent, plugged);
+  }
 
   /* zero buffer */
   memset(out, 0, sizeof(out));
@@ -145,7 +163,10 @@ main(int argc, char *argv[])
       if (strcmp(s, "PNP") == 0) {
         if (strcmp(out[2], "00000080") == 0) {
           if (strcmp(out[3], "00000001") == 0) {
-            on_battery_event(battery_percent(), plugged);
+            percent = battery_percent();
+            if (percent == NULL) {
+              on_battery_event(percent, plugged);
+            }
           }
         }
       }

src/wayland.c

@@ -118,16 +118,12 @@ pre_exit(int signal)
 
   zwp_idle_inhibit_manager_v1_destroy(data->inhibitmanager);
   wl_registry_destroy(data->registry);
+  // wl_display_destroy(data->display);
   wl_compositor_destroy(data->compositor);
 	wl_surface_destroy(data->surface);
-	/* TODO: this causes a segfault
-		wl_display_destroy(data->display);
-	*/
 
   /* make sure to cleanup the allocated data */
   free(data);
-
-  exit(0);
 }
 
 int