Messages in this thread Patch in this message | | | Date | Thu, 27 Sep 2012 19:47:09 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [RFC] tty: Add get- ioctls to fetch tty status |
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On Thu, Sep 27, 2012 at 04:13:12PM +0100, Alan Cox wrote: > > Well, sure inside our tool before doing checkpoint we stop all > > tasks which are part of dumpee process tree. This unfortunatly > > doesn't apply to these ioctl calls. Peter, any idea how to deal > > with that? > > I suspect you can't deal with that. Which isn't to say you can't still > build something useful. The query interfaces are trivial enough and > beyond that it's simply a case of documenting that they are not intended > to be generically "safe" but provide a spot sample. > > Otherwise - TICOGPKT is specific to pty devices. Please therefore put it > in the pty.c code and note that not all platforms use asm-geneic TTY > ioctls so check carefully they all build.
Alan, I've moved the TICOGPKT to pty code but where to puts information about unsafety of the data obtained? Also I fear I can test the build results and run-time behaviour on x86 machine only, which I own (well, couple of them). Though I defined this ioctls the same way as existing ioctl codes are defined so I think all should build the same. --- From: Cyrill Gorcunov <gorcunov@openvz.org> Subject: tty: Add get- ioctls to fetch tty status v2
For checkpoint/restore we need to know if tty has exclusive or packet mode set, as well as if pty is currently locked. Just to be able to restore this characteristics.
For this sake the following ioctl codes are introduced
- TIOCGPKT to get packet mode state - TIOCGPTLCK to get Pty locked state - TIOCGEXCL to get Exclusive mode state
v2: - Use TIOC prefix for ioctl codes (by jslaby@) - Move TIOCGPKT to pty code (by alan@)
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> --- drivers/tty/pty.c | 34 ++++++++++++++++++++++++++++++++++ drivers/tty/tty_io.c | 7 +++++++ fs/compat_ioctl.c | 3 +++ include/asm-generic/ioctls.h | 3 +++ 4 files changed, 47 insertions(+)
Index: tty.git/drivers/tty/pty.c =================================================================== --- tty.git.orig/drivers/tty/pty.c +++ tty.git/drivers/tty/pty.c @@ -174,6 +174,32 @@ static int pty_set_lock(struct tty_struc return 0; } +static int pty_get_lock(struct tty_struct *tty, int __user *arg) +{ + int locked = test_bit(TTY_PTY_LOCK, &tty->flags); + if (put_user(locked, arg)) + return -EFAULT; + return 0; +} + +static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) +{ + unsigned long flags; + int pktmode; + + if (tty->driver->subtype != PTY_TYPE_MASTER) + return -ENOTTY; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + pktmode = tty->packet; + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + if (put_user(pktmode, arg)) + return -EFAULT; + + return 0; +} + /* Send a signal to the slave */ static int pty_signal(struct tty_struct *tty, int sig) { @@ -393,8 +419,12 @@ static int pty_bsd_ioctl(struct tty_stru switch (cmd) { case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ return pty_set_lock(tty, (int __user *) arg); + case TIOCGPTLCK: /* Get PT Lock status */ + return pty_get_lock(tty, (int __user *)arg); case TIOCSIG: /* Send signal to other side of pty */ return pty_signal(tty, (int) arg); + case TIOCGPKT: /* Get PT packet mode status */ + return pty_get_pktmode(tty, (int __user *)arg); } return -ENOIOCTLCMD; } @@ -507,10 +537,14 @@ static int pty_unix98_ioctl(struct tty_s switch (cmd) { case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ return pty_set_lock(tty, (int __user *)arg); + case TIOCGPTLCK: /* Get PT Lock status */ + return pty_get_lock(tty, (int __user *)arg); case TIOCGPTN: /* Get PT Number */ return put_user(tty->index, (unsigned int __user *)arg); case TIOCSIG: /* Send signal to other side of pty */ return pty_signal(tty, (int) arg); + case TIOCGPKT: /* Get PT packet mode status */ + return pty_get_pktmode(tty, (int __user *)arg); } return -ENOIOCTLCMD; Index: tty.git/drivers/tty/tty_io.c =================================================================== --- tty.git.orig/drivers/tty/tty_io.c +++ tty.git/drivers/tty/tty_io.c @@ -2693,6 +2693,13 @@ long tty_ioctl(struct file *file, unsign case TIOCNXCL: clear_bit(TTY_EXCLUSIVE, &tty->flags); return 0; + case TIOCGEXCL: + { + int excl = test_bit(TTY_EXCLUSIVE, &tty->flags); + if (put_user(excl, (int __user *)p)) + return -EFAULT; + return 0; + } case TIOCNOTTY: if (current->signal->tty != tty) return -ENOTTY; Index: tty.git/fs/compat_ioctl.c =================================================================== --- tty.git.orig/fs/compat_ioctl.c +++ tty.git/fs/compat_ioctl.c @@ -842,6 +842,9 @@ COMPATIBLE_IOCTL(TIOCGDEV) COMPATIBLE_IOCTL(TIOCCBRK) COMPATIBLE_IOCTL(TIOCGSID) COMPATIBLE_IOCTL(TIOCGICOUNT) +COMPATIBLE_IOCTL(TIOCGPKT) +COMPATIBLE_IOCTL(TIOCGPTLCK) +COMPATIBLE_IOCTL(TIOCGEXCL) /* Little t */ COMPATIBLE_IOCTL(TIOCGETD) COMPATIBLE_IOCTL(TIOCSETD) Index: tty.git/include/asm-generic/ioctls.h =================================================================== --- tty.git.orig/include/asm-generic/ioctls.h +++ tty.git/include/asm-generic/ioctls.h @@ -74,6 +74,9 @@ #define TCSETXW 0x5435 #define TIOCSIG _IOW('T', 0x36, int) /* pty: generate signal */ #define TIOCVHANGUP 0x5437 +#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */ +#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */ +#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */ #define FIONCLEX 0x5450 #define FIOCLEX 0x5451
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