feat(main_loop): subshell start

src/main.c

@@ -7,70 +7,9 @@
 #include "lexer/lexer.h"
 #include "parser/parser.h"
 #include "utils/args/args.h"
+#include "utils/main_loop/main_loop.h"
 #include "utils/vars/vars.h"
 
-// === Error codes
-
-#define SUCCESS 0
-#define ERR_INPUT_PROCESSING 2
-#define ERR_MALLOC 3
-#define ERR_GENERIC 4
-
-// === Functions
-
-/* @brief: frees the hash map.
- * @return: always ERR_INPUT_PROCESSING.
- */
-static int err_input(struct hash_map **vars, struct lexer_context *ctx)
-{
-    hash_map_free(vars);
-    destroy_lexer_context(ctx);
-    return ERR_INPUT_PROCESSING;
-}
-
-static int main_loop(struct lexer_context *ctx, struct hash_map *vars)
-{
-    int return_code = SUCCESS;
-    // init parser
-    if (!parser_init())
-    {
-        perror("parser initialization failed.");
-    }
-
-    // Retrieve and build first AST
-    struct ast *command_ast = get_ast(ctx);
-
-    // Main parse-execute loop
-    while (command_ast != NULL && command_ast->type != AST_END)
-    {
-        if (command_ast->type != AST_VOID)
-        {
-            // Execute AST
-            return_code = execution(command_ast, vars);
-
-            // set $? variable
-            set_var_int(vars, "?", return_code);
-        }
-
-        ast_free(&command_ast);
-
-        // Retrieve and build next AST
-        command_ast = get_ast(ctx);
-    }
-
-    if (command_ast == NULL)
-        return err_input(&vars, ctx);
-
-    // === free
-
-    ast_free(&command_ast);
-    parser_close();
-    hash_map_free(&vars);
-    destroy_lexer_context(ctx);
-
-    return return_code;
-}
-
 int main(int argc, char **argv)
 {
     struct hash_map *vars = vars_init();
@@ -117,7 +56,16 @@ int main(int argc, char **argv)
     // init lexer context
     struct lexer_context *ctx = calloc(1, sizeof(struct lexer_context));
 
+    // init parser
+    if (!parser_init())
+    {
+        perror("parser initialization failed.");
+        return err_input(&vars, ctx);
+    }
+
     return_code = main_loop(ctx, vars);
 
+    parser_close();
+
     return return_code;
 }

src/utils/Makefile.am

@@ -20,6 +20,7 @@ libutils_a_SOURCES =  \
 	ast/ast_loop.c \
 	args/args.c \
 	vars/vars.c \
+	main_loop/main_loop.c \
 	ast/ast_assignment.c \
 	ast/ast_subshell.c \
 	ast/ast_function.c

src/utils/main_loop/main_loop.c

@@ -0,0 +1,111 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include "main_loop.h"
+
+// === Includes
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "../../execution/execution.h"
+#include "../../io_backend/io_backend.h"
+#include "../../lexer/lexer.h"
+#include "../../parser/parser.h"
+#include "../args/args.h"
+#include "../vars/vars.h"
+
+// === Functions
+
+int err_input(struct hash_map **vars, struct lexer_context *ctx)
+{
+    hash_map_free(vars);
+    destroy_lexer_context(ctx);
+    return ERR_INPUT_PROCESSING;
+}
+
+int main_loop(struct lexer_context *ctx, struct hash_map *vars)
+{
+    int return_code = SUCCESS;
+
+    // Retrieve and build first AST
+    struct ast *command_ast = get_ast(ctx);
+
+    // Main parse-execute loop
+    while (command_ast != NULL && command_ast->type != AST_END)
+    {
+        if (command_ast->type != AST_VOID)
+        {
+            // Execute AST
+            return_code = execution(command_ast, vars);
+
+            // set $? variable
+            set_var_int(vars, "?", return_code);
+        }
+
+        ast_free(&command_ast);
+
+        // Retrieve and build next AST
+        command_ast = get_ast(ctx);
+    }
+
+    if (command_ast == NULL)
+        return err_input(&vars, ctx);
+
+    // === free
+
+    ast_free(&command_ast);
+    hash_map_free(&vars);
+    destroy_lexer_context(ctx);
+
+    return return_code;
+}
+
+/* @brief: initializes a lexer context from a command string.
+ * @return: pointer to the lexer context, or NULL on failure.
+ */
+static struct lexer_context *lexer_init_from_string(char *command)
+{
+    // Create a lexer context from the command string
+    struct lexer_context *ctx = calloc(1, sizeof(struct lexer_context));
+    if (ctx == NULL)
+        return NULL;
+
+    ctx->end_previous_token = strdup(command);
+    if (ctx->end_previous_token == NULL)
+    {
+        free(ctx);
+        return NULL;
+    }
+    ctx->remaining_chars = strlen(command);
+
+    return ctx;
+}
+
+int start_subshell(struct hash_map **parent_vars, char *command)
+{
+    int fd = fork();
+    if (fd < 0)
+        return ERR_GENERIC;
+
+    else if (fd == 0) // Child process
+    {
+        struct lexer_context *ctx = lexer_init_from_string(command);
+        if (ctx == NULL)
+            return ERR_MALLOC;
+        int return_code = main_loop(ctx, *parent_vars);
+        exit(return_code);
+    }
+    else // Parent process
+    {
+        int status;
+        if (waitpid(fd, &status, 0) == -1)
+            return ERR_GENERIC;
+        if (WIFEXITED(status))
+            return WEXITSTATUS(status);
+        else
+            return ERR_GENERIC;
+    }
+}

src/utils/main_loop/main_loop.h

@@ -0,0 +1,31 @@
+#ifndef MAIN_LOOP_H
+#define MAIN_LOOP_H
+
+#include "../../utils/vars/vars.h"
+#include "../../lexer/lexer.h"
+
+// === Error codes
+#define SUCCESS 0
+#define ERR_INPUT_PROCESSING 2
+#define ERR_MALLOC 3
+#define ERR_GENERIC 4
+
+/* @brief: main loop called from main.
+ * @return: exit code.
+ */
+int main_loop(struct lexer_context *ctx, struct hash_map *vars);
+
+/*
+ * @brief: frees the hash map and lexer context.
+ * @return: ERR_INPUT_PROCESSING.
+ */
+int err_input(struct hash_map **vars, struct lexer_context *ctx);
+
+/*
+ * @brief: starts a subshell and builds the intern lexer context
+ * from the string.
+ * @return: exit code of the subshell.
+ */
+int start_subshell(struct hash_map **parent_vars, char *command);
+
+#endif /* MAIN_LOOP_H */