fix(execution): reimplemented the builtins

src/execution/execution_helpers.c

@@ -208,9 +208,97 @@ int exec_ast_redir(struct ast_redir *redir, struct hash_map *vars)
     return ret;
 }
 
-// Dummy try_builtin for linking
-static int try_builtin(char **argv)
+// --- Builtins ---
+
+static int builtin_echo(char **argv)
+{
+    bool newline = true;
+    int i = 1;
+
+    if (argv[1] && strcmp(argv[1], "-n") == 0)
+    {
+        newline = false;
+        i++;
+    }
+
+    for (; argv[i]; i++)
+    {
+        printf("%s", argv[i]);
+        if (argv[i + 1])
+            printf(" ");
+    }
+    if (newline)
+        printf("\n");
+
+    fflush(stdout);
+    return 0;
+}
+
+
+static int builtin_true(char **argv)
 {
     (void)argv;
+    return 0;
+}
+
+static int builtin_false(char **argv)
+{
+    (void)argv;
+    return 1;
+}
+
+static int builtin_exit(char **argv)
+{
+    int exit_val = 0;
+    if (argv[1])
+        exit_val = atoi(argv[1]);
+    exit(exit_val);
+    return exit_val;
+}
+
+
+static int builtin_cd(char **argv)
+{
+    const char *path = argv[1];
+    if (!path)
+    {
+        path = getenv("HOME");
+        if (!path)
+        {
+            fprintf(stderr, "cd: HOME not set\n");
+            return 1;
+        }
+    }
+    if (chdir(path) != 0)
+    {
+        perror("cd");
+        return 1;
+    }
+    return 0;
+}
+
+
+/**
+ * @brief Tries to execute a builtin command if the command matches a builtin
+ *
+ * @param argv Array of command arguments
+ * @return int Exit status of the builtin command, or -1 if not a builtin
+ */
+static int try_builtin(char **argv)
+{
+    if (!argv || !argv[0])
+        return 0;
+
+    if (strcmp(argv[0], "echo") == 0)
+        return builtin_echo(argv);
+    if (strcmp(argv[0], "true") == 0)
+        return builtin_true(argv);
+    if (strcmp(argv[0], "false") == 0)
+        return builtin_false(argv);
+    if (strcmp(argv[0], "exit") == 0)
+        return builtin_exit(argv);
+    if (strcmp(argv[0], "cd") == 0)
+        return builtin_cd(argv);
+
     return -1;
 }