sigact: Don't write sa_entry from parasite code

Pull the array of rt_sigact_t-s to the crtools instead and fill+write sa_entries there.
This is required to switch to protobuf, since we cannot use pb lib code in parasite for
encoding sa_entries.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/parasite.h

@@ -48,6 +48,10 @@ struct parasite_dump_pages_args {
 	unsigned long		nrpages_total;
 };
 
+struct parasite_dump_sa_args {
+	rt_sigaction_t sas[SIGMAX];
+};
+
 /*
  * Misc sfuff, that is too small for separate file, but cannot
  * be read w/o using parasite

parasite-syscall.c

@@ -453,8 +453,30 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, pid_t pid,
 
 int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset)
 {
-	return parasite_file_cmd("sigactions", PARASITE_CMD_DUMP_SIGACTS,
-				 CR_FD_SIGACT, ctl, cr_fdset);
+	struct parasite_dump_sa_args args;
+	int ret, i, fd;
+	struct sa_entry se;
+
+	ret = parasite_execute(PARASITE_CMD_DUMP_SIGACTS, ctl, &args, sizeof(args));
+	if (ret < 0)
+		return ret;
+
+	fd = fdset_fd(cr_fdset, CR_FD_SIGACT);
+
+	for (i = 1; i < SIGMAX; i++) {
+		if (i == SIGSTOP || i == SIGKILL)
+			continue;
+
+		ASSIGN_TYPED(se.sigaction, args.sas[i].rt_sa_handler);
+		ASSIGN_TYPED(se.flags, args.sas[i].rt_sa_flags);
+		ASSIGN_TYPED(se.restorer, args.sas[i].rt_sa_restorer);
+		ASSIGN_TYPED(se.mask, args.sas[i].rt_sa_mask.sig[0]);
+
+		if (write_img(fd, &se) < 0)
+			return -1;
+	}
+
+	return 0;
 }
 
 int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset)

parasite.c

@@ -262,40 +262,21 @@ static int dump_pages_fini(void)
 	return sys_close(fd_pages);
 }
 
-static int dump_sigact()
+static int dump_sigact(struct parasite_dump_sa_args *da)
 {
-	rt_sigaction_t act;
-	struct sa_entry e;
-	int fd, sig;
-	int ret;
-
-	fd = recv_fd(tsock);
-	if (fd < 0)
-		return fd;
+	int sig, ret;
 
 	for (sig = 1; sig < SIGMAX; sig++) {
 		if (sig == SIGKILL || sig == SIGSTOP)
 			continue;
 
-		ret = sys_sigaction(sig, NULL, &act, sizeof(rt_sigset_t));
+		ret = sys_sigaction(sig, NULL, &da->sas[sig], sizeof(rt_sigset_t));
 		if (ret < 0) {
 			sys_write_msg("sys_sigaction failed\n");
-			goto err_close;
+			break;
 		}
-
-		ASSIGN_TYPED(e.sigaction, act.rt_sa_handler);
-		ASSIGN_TYPED(e.flags, act.rt_sa_flags);
-		ASSIGN_TYPED(e.restorer, act.rt_sa_restorer);
-		ASSIGN_TYPED(e.mask, act.rt_sa_mask.sig[0]);
-
-		ret = sys_write_safe(fd, &e, sizeof(e));
-		if (ret)
-			goto err_close;
 	}
 
-	ret = 0;
-err_close:
-	sys_close(fd);
 	return ret;
 }
 
@@ -470,7 +451,7 @@ int __used parasite_service(unsigned long cmd, void *args)
 	case PARASITE_CMD_DUMPPAGES:
 		return dump_pages((struct parasite_dump_pages_args *)args);
 	case PARASITE_CMD_DUMP_SIGACTS:
-		return dump_sigact();
+		return dump_sigact((struct parasite_dump_sa_args *)args);
 	case PARASITE_CMD_DUMP_ITIMERS:
 		return dump_itimers();
 	case PARASITE_CMD_DUMP_MISC: