From 4b10d7ea4d3196eecbdfa1324e03a06feba6497e Mon Sep 17 00:00:00 2001
From: kamkow1 <ikamileq@gmail.com>
Date: Sun, 9 Mar 2025 18:32:10 +0100
Subject: [PATCH] Implement init rc script, similar to .gdbinit

---
 .debugusrc.js | 13 +++++++++++++
 debugus.c     | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 .debugusrc.js

diff --git a/.debugusrc.js b/.debugusrc.js
new file mode 100644
index 0000000..b9fdfb8
--- /dev/null
+++ b/.debugusrc.js
@@ -0,0 +1,13 @@
+log_inf("Loading init script for program ./test");
+log_err("Test error message");
+
+var main_offset = "0x0000000000001135"; // objdump -d ./test
+
+// Testing...
+print_file();
+print_dbg_pid();
+print_program_load_offset();
+mk_brk_addr(main_offset);
+list_brks();
+cont();
+
diff --git a/debugus.c b/debugus.c
index 55ce61e..c9efa02 100644
--- a/debugus.c
+++ b/debugus.c
@@ -23,6 +23,8 @@
 
 #define shift(argc, argv, msg, ...) (argc <= 0 ? (LOG_ERR(msg, ##__VA_ARGS__), exit(EXIT_FAILURE)) : (void)0, argc--, *argv++)
 
+#define INIT_SCRIPT ".debugusrc.js"
+
 // How breakpoints work?
 // We can enable/disable breakpoints by putting/removing an int 3 instruction
 // into/from the executed program. int 3 will trigger a SIGTRAP, which we can
@@ -160,6 +162,20 @@ void dbg_js_list_brks(js_State *js)
     js_pushundefined(js);
 }
 
+void dbg_js_log_inf(js_State *js)
+{
+    const char *str = js_tostring(js, 1);
+    LOG_INF("%s\n", str);
+    js_pushundefined(js);
+}
+
+void dbg_js_log_err(js_State *js)
+{
+    const char *str = js_tostring(js, 1);
+    LOG_ERR("%s\n", str);
+    js_pushundefined(js);
+}
+
 void dbg_init_js(Dbg *dbg)
 {
     dbg->js   = js_newstate(NULL, NULL, JS_STRICT);
@@ -178,6 +194,8 @@ void dbg_init_js(Dbg *dbg)
     make_js_func(list_brks, 0);
     make_js_func(set_program_load_offset, 1);
     make_js_func(print_program_load_offset, 0);
+    make_js_func(log_inf, 1);
+    make_js_func(log_err, 1);
 
     #undef make_js_func
 }
@@ -201,6 +219,25 @@ void dbg_init_load_offset(Dbg *dbg)
     pmparser_free(&maps_iter);
 }
 
+void dbg_load_init_script(Dbg *dbg, const char *script_path)
+{
+    FILE *script = fopen(script_path, "r");
+    if (script == NULL) {
+        return;
+    }
+
+    fseek(script, 0L, SEEK_END);
+    long size = ftell(script);
+    rewind(script);
+    char *script_buf = malloc(size+1);
+    fread(script_buf, size, 1, script);
+    script_buf[size] = '\0';
+
+    js_dostring(dbg->js, script_buf);
+
+    fclose(script);
+}
+
 void dbg_init(Dbg *dbg, const char *file, pid_t pid)
 {
     memset(dbg, 0, sizeof(*dbg));
@@ -209,6 +246,8 @@ void dbg_init(Dbg *dbg, const char *file, pid_t pid)
     dbg_init_js(dbg);
     dbg_init_load_offset(dbg);
     hashtable_init(&dbg->brks, MAX_BRKS);
+
+    dbg_load_init_script(dbg, INIT_SCRIPT);
 }
 
 void dbg_deinit(Dbg *dbg)