From 6c3f8259e9dd5d30e27e214d363a5eef0760a479 Mon Sep 17 00:00:00 2001
From: Chris Cromer <chris@cromer.cl>
Date: Fri, 16 Jul 2021 14:16:53 -0400
Subject: [PATCH] make StringArrays NULL terminated

---
 src/array.c  | 16 +++++++++++++---
 src/launch.c | 14 ++++----------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/array.c b/src/array.c
index cf60ace..0c2bbed 100644
--- a/src/array.c
+++ b/src/array.c
@@ -23,6 +23,10 @@
  */
 StringArray *create_string_array() {
     StringArray *string_array = malloc(sizeof(StringArray));
+    if (string_array == NULL) {
+        perror("malloc");
+        exit(EXIT_FAILURE);
+    }
     string_array->array = NULL;
     string_array->size = 0;
     return string_array;
@@ -35,25 +39,30 @@ StringArray *create_string_array() {
  */
 void insert_string_array(StringArray *string_array, char *string) {
     if (string_array->size == 0) {
-        string_array->array = malloc(sizeof(char *));
+        string_array->array = malloc(2 * sizeof(char *));
         if (string_array->array == NULL) {
             perror("malloc");
+            free_string_array(string_array);
             exit(EXIT_FAILURE);
         }
     }
     else {
-        string_array->array = realloc(string_array->array, (string_array->size + 1) * sizeof(char *));
+        string_array->array = realloc(string_array->array, (string_array->size + 2) * sizeof(char *));
         if (string_array->array == NULL) {
             perror("realloc");
+            free_string_array(string_array);
             exit(EXIT_FAILURE);
         }
     }
     string_array->array[string_array->size] = malloc(sizeof(string));
     if (string_array->array == NULL) {
         perror("malloc");
+        free_string_array(string_array);
         exit(EXIT_FAILURE);
     }
     strcpy(string_array->array[string_array->size], string);
+    // A NULL terminated array
+    string_array->array[string_array->size + 1] = NULL;
     string_array->size++;
 }
 
@@ -76,9 +85,10 @@ void delete_string_array(StringArray *string_array, int index) {
         }
         free(string_array->array[string_array->size - 1]);
         string_array->array[string_array->size - 1] = NULL;
-        string_array->array = realloc(string_array->array, (string_array->size - 1) * sizeof(char *));
+        string_array->array = realloc(string_array->array, (string_array->size) * sizeof(char *));
         if (string_array->array == NULL) {
             perror("realloc");
+            free_string_array(string_array);
             exit(EXIT_FAILURE);
         }
         string_array->size--;
diff --git a/src/launch.c b/src/launch.c
index 128c07b..00b8938 100644
--- a/src/launch.c
+++ b/src/launch.c
@@ -30,17 +30,11 @@ void launch_program(StringArray *args) {
     child = fork();
 
     if (child == 0) {
-        // Copy the array and add a NULL to the end of it
-        char *argv[args->size + 1];
-        for (size_t i = 0; i < args->size; i++) {
-            argv[i] = args->array[i];
+        if (execvp(args->array[0], args->array) == -1) {
+            fprintf(stderr, "%s: command not found\n", args->array[0]);
+            free_string_array(args);
+            exit(EXIT_FAILURE);
         }
-        argv[args->size] = NULL;
-
-        execvp(args->array[0], argv);
-        fprintf(stderr, "%s: command not found\n", args->array[0]);
-        free_string_array(args);
-        exit(EXIT_FAILURE);
     }
     else if (child < 0) {
         perror("fork");