compel: Relax the thread mgmt API

Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

compel/include/infect-priv.h

@@ -42,6 +42,8 @@ struct parasite_ctl {
 };
 
 struct parasite_thread_ctl {
+	int			tid;
+	struct parasite_ctl	*ctl;
 	struct thread_ctx	th;
 };
 

compel/include/uapi/infect.h

@@ -64,9 +64,7 @@ extern void *compel_parasite_args_s(struct parasite_ctl *ctl, int args_size);
 
 extern int compel_execute_syscall(struct parasite_ctl *ctl,
 		user_regs_struct_t *regs, const char *code_syscall);
-extern int compel_run_in_thread(pid_t pid, unsigned int cmd,
-					struct parasite_ctl *ctl,
-					struct parasite_thread_ctl *tctl);
+extern int compel_run_in_thread(struct parasite_thread_ctl *tctl, unsigned int cmd);
 
 /*
  * The PTRACE_SYSCALL will trap task twice -- on
@@ -139,7 +137,7 @@ struct parasite_blob_desc {
 extern struct parasite_blob_desc *compel_parasite_blob_desc(struct parasite_ctl *);
 
 typedef int (*save_regs_t)(void *, user_regs_struct_t *, user_fpregs_struct_t *);
-extern int compel_get_thread_regs(pid_t pid, struct parasite_thread_ctl *, save_regs_t, void *);
+extern int compel_get_thread_regs(struct parasite_thread_ctl *, save_regs_t, void *);
 
 extern void compel_relocs_apply(void *mem, void *vbase, size_t size, compel_reloc_t *elf_relocs, size_t nr_relocs);
 

compel/src/lib/infect.c

@@ -856,6 +856,9 @@ struct parasite_thread_ctl *compel_prepare_thread(struct parasite_ctl *ctl, int
 		if (prepare_thread(pid, &tctl->th)) {
 			xfree(tctl);
 			tctl = NULL;
+		} else {
+			tctl->tid = pid;
+			tctl->ctl = ctl;
 		}
 	}
 
@@ -1083,10 +1086,10 @@ void *compel_parasite_args_s(struct parasite_ctl *ctl, int args_size)
 	return compel_parasite_args_p(ctl);
 }
 
-int compel_run_in_thread(pid_t pid, unsigned int cmd,
-					struct parasite_ctl *ctl,
-					struct parasite_thread_ctl *tctl)
+int compel_run_in_thread(struct parasite_thread_ctl *tctl, unsigned int cmd)
 {
+	int pid = tctl->tid;
+	struct parasite_ctl *ctl = tctl->ctl;
 	struct thread_ctx *octx = &tctl->th;
 	void *stack = ctl->r_thread_stack;
 	user_regs_struct_t regs = octx->regs;
@@ -1297,9 +1300,9 @@ k_rtsigset_t *compel_task_sigmask(struct parasite_ctl *ctl)
 	return thread_ctx_sigmask(&ctl->orig);
 }
 
-int compel_get_thread_regs(pid_t pid, struct parasite_thread_ctl *tctl, save_regs_t save, void * arg)
+int compel_get_thread_regs(struct parasite_thread_ctl *tctl, save_regs_t save, void * arg)
 {
-	return get_task_regs(pid, tctl->th.regs, save, arg);
+	return get_task_regs(tctl->tid, tctl->th.regs, save, arg);
 }
 
 struct infect_ctx *compel_infect_ctx(struct parasite_ctl *ctl)

criu/parasite-syscall.c

@@ -203,7 +203,7 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
 	tc->has_blk_sigset = true;
 	memcpy(&tc->blk_sigset, compel_thread_sigmask(tctl), sizeof(k_rtsigset_t));
 
-	ret = compel_run_in_thread(pid, PARASITE_CMD_DUMP_THREAD, ctl, tctl);
+	ret = compel_run_in_thread(tctl, PARASITE_CMD_DUMP_THREAD);
 	if (ret) {
 		pr_err("Can't init thread in parasite %d\n", pid);
 		goto err_rth;
@@ -215,7 +215,7 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
 		goto err_rth;
 	}
 
-	ret = compel_get_thread_regs(pid, tctl, save_task_regs, core);
+	ret = compel_get_thread_regs(tctl, save_task_regs, core);
 	if (ret) {
 		pr_err("Can't obtain regs for thread %d\n", pid);
 		goto err_rth;