Prompt to embedded mujs engine

debugus.c

@@ -1,6 +1,88 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/ptrace.h>
 
-int main(void)
+#include "linenoise.h"
+#include "mujs.h"
+
+#define LOG_ERR(fmt, ...) fprintf(stderr, "Error: " fmt, ##__VA_ARGS__)
+#define LOG_INF(fmt, ...) fprintf(stdout, "Info:  " fmt, ##__VA_ARGS__)
+
+#define unused(x) ((void)(x))
+
+#define shift(argc, argv, msg, ...) (argc <= 0 ? (LOG_ERR(msg, ##__VA_ARGS__), exit(EXIT_FAILURE)) : (void)0, argc--, *argv++)
+
+typedef struct {
+    const char *file;
+    pid_t pid;
+    js_State *js;
+} Dbg;
+
+void dbg_js_print_file(js_State *js)
 {
+    void *data = js_currentfunctiondata(js);
+    Dbg *dbg = (Dbg *)data;
+
+    printf("File: %s\n", dbg->file);
+}
+
+void dbg_init_js(Dbg *dbg)
+{
+    dbg->js   = js_newstate(NULL, NULL, JS_STRICT);
+
+    js_newcfunctionx(dbg->js, &dbg_js_print_file, "print_file", 0, dbg, NULL);
+    js_setglobal(dbg->js, "print_file");
+}
+
+void dbg_init(Dbg *dbg, const char *file, pid_t pid)
+{
+    dbg->file = file;
+    dbg->pid  = pid;
+    dbg_init_js(dbg);
+}
+
+void dbg_deinit(Dbg *dbg)
+{
+    js_freestate(dbg->js);
+}
+
+void dbg_loop(Dbg *dbg)
+{
+    int status, options = 0;
+    waitpid(dbg->pid, &status, options);
+
+    char *line = NULL;
+    while ((line = linenoise("debugus # ")) != NULL) {
+        js_dostring(dbg->js, line);
+        linenoiseHistoryAdd(line);
+        linenoiseFree(line);
+    }
+}
+
+void start_debugging(const char *input_file_path)
+{
+    pid_t pid = fork();
+    if (pid == 0) {
+        /* ptrace(PTRACE_TRACEME, 0, NULL, NULL); */
+        /* execl(input_file_path, input_file_path, NULL); */
+    } else if (pid >= 1) {
+        Dbg dbg;
+        dbg_init(&dbg, input_file_path, pid);
+        dbg_loop(&dbg);
+        dbg_deinit(&dbg);
+    }
+}
+
+int main(int argc, char ** argv)
+{
+    const char *program_name = shift(argc, argv, "");
+    unused(program_name);
+
+    const char *input_file_path = shift(argc, argv, "No input file provided\n");
+    start_debugging(input_file_path);
+
     return 0;
 }