diff --git a/config_file.c b/config_file.c
index a27e2e9e37..b489f7ba8f 100644
--- a/config_file.c
+++ b/config_file.c
@@ -18,7 +18,7 @@ struct config_file
 
 static char *getaline(FILE *file)
 {
-   char *newline = malloc(8);
+   char *newline = malloc(9);
    size_t cur_size = 8;
    size_t index = 0;
 
@@ -28,12 +28,13 @@ static char *getaline(FILE *file)
       if (index == cur_size)
       {
          cur_size *= 2;
-         newline = realloc(newline, cur_size);
+         newline = realloc(newline, cur_size + 1);
       }
 
       newline[index++] = in;
       in = getc(file);
    }
+   newline[index] = '\0';
    return newline; 
 }
 
@@ -48,7 +49,7 @@ static bool parse_line(struct entry_list *list, char *line)
    while (isspace(*line))
       line++;
 
-   char *key = malloc(8);
+   char *key = malloc(9);
    size_t cur_size = 8;
    size_t index = 0;
 
@@ -57,11 +58,12 @@ static bool parse_line(struct entry_list *list, char *line)
       if (index == cur_size)
       {
          cur_size *= 2;
-         key = realloc(key, cur_size);
+         key = realloc(key, cur_size + 1);
       }
 
       key[index++] = *line++;
    }
+   key[index] = '\0';
    list->key = key;
 
    while (isspace(*line))
diff --git a/config_file.h b/config_file.h
index 67e083e7db..8b0b0b71ba 100644
--- a/config_file.h
+++ b/config_file.h
@@ -6,13 +6,28 @@
 
 typedef struct config_file config_file_t;
 
+/////
+// Config file format
+// - # are treated as comments. Rest of the line is ignored.
+// - Format is: key = value. There can be as many spaces as you like in-between.
+// - Value can be wrapped inside "" for multiword strings. (foo = "hai u")
+
+// Loads a config file. Returns NULL if file doesn't exist.
 config_file_t *config_file_new(const char *path);
+// Frees config file.
 void config_file_free(config_file_t *conf);
 
+// All extract functions return true when value is valid and exists. Returns false otherwise.
+
+// Extracts a double from config file.
 bool config_get_double(config_file_t *conf, const char *entry, double *in);
+// Extracts an int from config file.
 bool config_get_int(config_file_t *conf, const char *entry, int *in);
+// Extracts a single char. If value consists of several chars, this is an error.
 bool config_get_char(config_file_t *conf, const char *entry, char *in);
+// Extracts an allocated string in *in. This must be free()-d if this function succeeds.
 bool config_get_string(config_file_t *conf, const char *entry, char **in);
+// Extracts a boolean from config. Valid boolean true are "true" and "1". Valid false are "false" and "0". Other values will be treated as an error.
 bool config_get_bool(config_file_t *conf, const char *entry, bool *in);