fix: stop segfaulting on non-existent directories

src/battery.c

@@ -3,6 +3,7 @@
 #include <stdbool.h>
 #include <unistd.h>
 
+#include "log.h"
 #include "utils.h"
 
 #include "config.h"
@@ -17,6 +18,10 @@ 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");
+    return NULL;
+  }
   free(d);
 
   /* create enough space for the battery percentage */

src/config.c

@@ -86,6 +86,7 @@ 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));

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"
@@ -124,6 +125,13 @@ 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',
@@ -51,19 +57,21 @@ on_battery_event(char *percent, bool plugged)
     /* convert battery percentage to an int */
     res = strtol(percent, &ep, 10);
 
-    if (res <= led_blink_trigger_level) {
-      rate = led_blink_timing_func(res);
-      if (rate >= 1) {
-        led_set_rate(rate);
+    wrap(led_ok,
+      if (res <= led_blink_trigger_level) {
+        rate = led_blink_timing_func(res);
+        if (rate >= 1) {
+          led_set_rate(rate);
+        }
+      } else {
+        led_set_rate(0);
       }
-    } else {
-      led_set_rate(0);
-    }
+    );
 
-		wayland_set_idle_lock(false);
+		wrap(wayland_ok, wayland_set_idle_lock(false));
   } else {
-    led_set_rate(0);
-		wayland_set_idle_lock(true);
+    wrap(led_ok, led_set_rate(0));
+		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);
+            }
           }
         }
       }