lib: launch: implement alternate argument handling to support interpreters

lib/liblaunch/include/launch.h

@@ -45,7 +45,9 @@ struct launch_ctx {
 struct launch_parameters {
 	kern_handle_t p_parent_task;
 	kern_handle_t p_local_address_space;
-	kern_handle_t p_executable;
+
+	const char *p_exec_path;
+	kern_handle_t p_exec_image;
 
 	const char *p_task_name;
 

lib/liblaunch/launch.c

@@ -38,6 +38,7 @@ static kern_handle_t get_library(
 
 static virt_addr_t write_bootstrap_data(
 	struct stack_writer *stack,
+	const char *interpreter,
 	const struct launch_parameters *params)
 {
 	virt_addr_t bs_remote;
@@ -51,9 +52,15 @@ static virt_addr_t write_bootstrap_data(
 	bs->bs_handles_count = params->p_handle_count;
 	bs->bs_channels_count = params->p_channel_count;
 
+	if (interpreter) {
+		/* two extra args: interpreter path and path to executable */
+		bs->bs_argc += 2;
+	}
+
 	const char **argv, **envp;
 
 	if (bs->bs_argc > 0) {
+		int argc = bs->bs_argc;
 		virt_addr_t remote_argv;
 		argv = stack_writer_put(
 			stack,
@@ -73,13 +80,22 @@ static virt_addr_t write_bootstrap_data(
 		bs->bs_envp = (const char **)remote_envp;
 	}
 
-	for (size_t i = 0; i < params->p_argc; i++) {
+	size_t i = 0, j = 0;
+	if (interpreter) {
 		virt_addr_t arg_ptr;
-		stack_writer_put_string(stack, params->p_argv[i], &arg_ptr);
+		stack_writer_put_string(stack, interpreter, &arg_ptr);
+		argv[i++] = (const char *)arg_ptr;
+		stack_writer_put_string(stack, params->p_exec_path, &arg_ptr);
+		argv[i++] = (const char *)arg_ptr;
+	}
+
+	for (; i < bs->bs_argc; i++, j++) {
+		virt_addr_t arg_ptr;
+		stack_writer_put_string(stack, params->p_argv[j], &arg_ptr);
 		argv[i] = (const char *)arg_ptr;
 	}
 
-	for (size_t i = 0; i < params->p_envc; i++) {
+	for (size_t i = 0; i < bs->bs_envc; i++) {
 		virt_addr_t env_ptr;
 		stack_writer_put_string(stack, params->p_envp[i], &env_ptr);
 		envp[i] = (const char *)env_ptr;
@@ -118,16 +134,20 @@ enum launch_status launch_ctx_execute(
 		return LAUNCH_ERR_TASK_CREATION_FAILED;
 	}
 
+	char interp_path[4096];
+	interp_path[0] = 0;
+
 	struct elf_image image;
 	elf_image_init(&image);
 
 	enum launch_status status = elf_image_load(
 		&image,
-		params->p_executable,
+		params->p_exec_image,
 		params->p_local_address_space,
 		remote_address_space);
 
 	if (status == LAUNCH_ERR_INTERPRETER_REQUIRED) {
+		snprintf(interp_path, sizeof interp_path, "%s", image.e_interp);
 		kern_handle_t interp = get_library(
 			ctx,
 			image.e_interp,
@@ -187,7 +207,7 @@ enum launch_status launch_ctx_execute(
 		&stack,
 		local_stack_buf + STACK_SIZE,
 		remote_stack_buf + STACK_SIZE);
-	virt_addr_t bsdata = write_bootstrap_data(&stack, params);
+	virt_addr_t bsdata = write_bootstrap_data(&stack, interp_path, params);
 
 	virt_addr_t ip = image.e_hdr.e_entry + image.e_remote_base;