[CRIU] [PATCH 1/2] tty: Make parasite to consider major and minors

[Cyrill Gorcunov]

For example TIOCGPKT and TIOCGPTLCK are pty specific
and should not be called for anything else (this
will be needed for other kind of terminals).

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
 include/parasite-syscall.h |  2 +-
 include/parasite.h         |  2 ++
 parasite-syscall.c         |  4 ++-
 pie/parasite.c             | 70 +++++++++++++++++++++++++++-------------------
 tty.c                      |  2 +-
 5 files changed, 48 insertions(+), 32 deletions(-)

diff --git a/include/parasite-syscall.h b/include/parasite-syscall.h
index 67840fcc658e..abdb5f8c1670 100644
--- a/include/parasite-syscall.h
+++ b/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 major, int minor);
 
 extern int parasite_init_threads_seized(struct parasite_ctl *ctl, struct pstree_item *item);
 extern int parasite_fini_threads_seized(struct parasite_ctl *ctl);
diff --git a/include/parasite.h b/include/parasite.h
index 774eba0c6d31..e14e4e1c7dcf 100644
--- a/include/parasite.h
+++ b/include/parasite.h
@@ -209,6 +209,8 @@ static inline int drain_fds_size(struct parasite_drain_fd *dfds)
 
 struct parasite_tty_args {
 	int	fd;
+	int	major;
+	int	minor;
 
 	int	sid;
 	int	pgrp;
diff --git a/parasite-syscall.c b/parasite-syscall.c
index 7cc1a84e0450..7a8d133a6a35 100644
--- a/parasite-syscall.c
+++ b/parasite-syscall.c
@@ -715,12 +715,14 @@ 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 major, int minor)
 {
 	struct parasite_tty_args *p;
 
 	p = parasite_args(ctl, struct parasite_tty_args);
 	p->fd = fd;
+	p->major = major;
+	p->minor = minor;
 
 	if (parasite_execute_daemon(PARASITE_CMD_DUMP_TTY, ctl) < 0)
 		return NULL;
diff --git a/pie/parasite.c b/pie/parasite.c
index bab67f8db089..dc2c4b9d9a09 100644
--- a/pie/parasite.c
+++ b/pie/parasite.c
@@ -6,6 +6,7 @@
 #include <sys/mount.h>
 #include <stdarg.h>
 #include <sys/ioctl.h>
+#include <linux/major.h>
 
 #include "syscall.h"
 #include "parasite.h"
@@ -317,6 +318,13 @@ static int parasite_dump_tty(struct parasite_tty_args *args)
 {
 	int ret;
 
+	args->sid = 0;
+	args->pgrp = 0;
+	args->st_pckt = 0;
+	args->st_lock = 0;
+	args->st_excl = 0;
+	args->hangup = true;
+
 #ifndef TIOCGPKT
 # define TIOCGPKT	_IOR('T', 0x38, int)
 #endif
@@ -329,44 +337,48 @@ 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;
-
-	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);
+	switch (args->major) {
+	case TTYAUX_MAJOR:
+		if (args->minor == 0 || args->minor == 2) {
+			__tty_ioctl(TIOCGPKT,	args->st_pckt);
+			__tty_ioctl(TIOCGPTLCK,	args->st_lock);
+		}
+		break;
+	case UNIX98_PTY_MASTER_MAJOR ... (UNIX98_PTY_MASTER_MAJOR + UNIX98_PTY_MAJOR_COUNT - 1):
+	case UNIX98_PTY_SLAVE_MAJOR:
+		__tty_ioctl(TIOCGPKT,	args->st_pckt);
+		__tty_ioctl(TIOCGPTLCK,	args->st_lock);
+		break;
+	}
+	__tty_ioctl(TIOCGEXCL,	args->st_excl);
 
 	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
diff --git a/tty.c b/tty.c
index edbe85e7505a..e86c60f3b91d 100644
--- a/tty.c
+++ b/tty.c
@@ -1072,7 +1072,7 @@ static int dump_pty_info(int lfd, u32 id, const struct fd_parms *p, int major, i
 	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, major, minor);
 	if (!pti)
 		return -1;
 
-- 
1.9.3