tty: parasite -- Don't call for TIOCGPKT/TIOCGPTLCK on non-ptys

We will have to support more tty types in future so
make calls depending on type of ttys.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/parasite-syscall.h

@@ -106,7 +106,7 @@ extern struct parasite_ctl *parasite_prep_ctl(pid_t pid,
 					      struct vm_area_list *vma_area_list);
 extern int parasite_map_exchange(struct parasite_ctl *ctl, unsigned long size);
 
-extern struct parasite_tty_args *parasite_dump_tty(struct parasite_ctl *ctl, int fd);
+extern struct parasite_tty_args *parasite_dump_tty(struct parasite_ctl *ctl, int fd, int type);
 
 extern int parasite_init_threads_seized(struct parasite_ctl *ctl, struct pstree_item *item);
 extern int parasite_fini_threads_seized(struct parasite_ctl *ctl);

include/parasite.h

@@ -209,6 +209,7 @@ static inline int drain_fds_size(struct parasite_drain_fd *dfds)
 
 struct parasite_tty_args {
 	int	fd;
+	int	type;
 
 	int	sid;
 	int	pgrp;

parasite-syscall.c

@@ -715,12 +715,13 @@ int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_mis
 	return 0;
 }
 
-struct parasite_tty_args *parasite_dump_tty(struct parasite_ctl *ctl, int fd)
+struct parasite_tty_args *parasite_dump_tty(struct parasite_ctl *ctl, int fd, int type)
 {
 	struct parasite_tty_args *p;
 
 	p = parasite_args(ctl, struct parasite_tty_args);
 	p->fd = fd;
+	p->type = type;
 
 	if (parasite_execute_daemon(PARASITE_CMD_DUMP_TTY, ctl) < 0)
 		return NULL;

pie/parasite.c

@@ -15,6 +15,7 @@
 #include "lock.h"
 #include "vdso.h"
 #include "log.h"
+#include "tty.h"
 
 #include <string.h>
 
@@ -329,44 +330,47 @@ static int parasite_dump_tty(struct parasite_tty_args *args)
 # define TIOCGEXCL	_IOR('T', 0x40, int)
 #endif
 
-	ret = tty_ioctl(args->fd, TIOCGSID, &args->sid);
-	if (ret < 0)
-		goto err;
-
-	ret = tty_ioctl(args->fd, TIOCGPGRP, &args->pgrp);
-	if (ret < 0)
-		goto err;
-
-	ret = tty_ioctl(args->fd, TIOCGPKT, &args->st_pckt);
-	if (ret < 0)
-		goto err;
-
-	ret = tty_ioctl(args->fd, TIOCGPTLCK, &args->st_lock);
-	if (ret < 0)
-		goto err;
+	args->sid = 0;
+	args->pgrp = 0;
+	args->st_pckt = 0;
+	args->st_lock = 0;
+	args->st_excl = 0;
 
-	ret = tty_ioctl(args->fd, TIOCGEXCL, &args->st_excl);
-	if (ret < 0)
-		goto err;
+#define __tty_ioctl(cmd, arg)					\
+	do {							\
+		ret = tty_ioctl(args->fd, cmd, &arg);		\
+		if (ret < 0) {					\
+			if (ret == -ENOTTY)			\
+				arg = 0;			\
+			else if (ret == -EIO)			\
+				goto err_io;			\
+			else					\
+				goto err;			\
+		}						\
+	} while (0)
+
+	__tty_ioctl(TIOCGSID, args->sid);
+	__tty_ioctl(TIOCGPGRP, args->pgrp);
+	__tty_ioctl(TIOCGEXCL,	args->st_excl);
+	
+	if (args->type == TTY_TYPE_PTM ||
+	    args->type == TTY_TYPE_PTS) {
+		__tty_ioctl(TIOCGPKT,	args->st_pckt);
+		__tty_ioctl(TIOCGPTLCK,	args->st_lock);
+	}
 
 	args->hangup = false;
 	return 0;
 
 err:
-	if (ret != -EIO) {
-		pr_err("TTY: Can't get sid/pgrp: %d\n", ret);
-		return -1;
-	}
+	pr_err("tty: Can't fetch params: err = %d\n", ret);
+	return -1;
+err_io:
 
 	/* kernel reports EIO for get ioctls on pair-less ptys */
-	args->sid = 0;
-	args->pgrp = 0;
-	args->st_pckt = 0;
-	args->st_lock = 0;
-	args->st_excl = 0;
 	args->hangup = true;
-
 	return 0;
+#undef __tty_ioctl
 }
 
 #ifdef CONFIG_VDSO

tty.c

@@ -1080,7 +1080,7 @@ static int dump_pty_info(int lfd, u32 id, const struct fd_parms *p, int type, in
 	BUILD_BUG_ON(sizeof(termios.c_cc) != sizeof(void *));
 	BUILD_BUG_ON((sizeof(termios.c_cc) * TERMIOS_NCC) < sizeof(t.c_cc));
 
-	pti = parasite_dump_tty(p->ctl, p->fd);
+	pti = parasite_dump_tty(p->ctl, p->fd, type);
 	if (!pti)
 		return -1;