Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 412 insertions, 0 deletions

diff --git a/drivers/char/pty.c b/drivers/char/pty.c
new file mode 100644
index 000000000000..da32889d22c0
--- /dev/null
+++ b/drivers/char/pty.c
@@ -0,0 +1,412 @@
+/*
+ *  linux/drivers/char/pty.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Added support for a Unix98-style ptmx device.
+ *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
+ *  Added TTY_DO_WRITE_WAKEUP to enable n_tty to send POLL_OUT to
+ *      waiting writers -- Sapan Bhatia <sapan@corewars.org>
+ *
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>       /* For EXPORT_SYMBOL */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/fcntl.h>
+#include <linux/string.h>
+#include <linux/major.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/sysctl.h>
+
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/bitops.h>
+#include <linux/devpts_fs.h>
+
+/* These are global because they are accessed in tty_io.c */
+#ifdef CONFIG_UNIX98_PTYS
+struct tty_driver *ptm_driver;
+static struct tty_driver *pts_driver;
+#endif
+
+static void pty_close(struct tty_struct * tty, struct file * filp)
+{
+        if (!tty)
+                return;
+        if (tty->driver->subtype == PTY_TYPE_MASTER) {
+                if (tty->count > 1)
+                        printk("master pty_close: count = %d!!\n", tty->count);
+        } else {
+                if (tty->count > 2)
+                        return;
+        }
+        wake_up_interruptible(&tty->read_wait);
+        wake_up_interruptible(&tty->write_wait);
+        tty->packet = 0;
+        if (!tty->link)
+                return;
+        tty->link->packet = 0;
+        set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
+        wake_up_interruptible(&tty->link->read_wait);
+        wake_up_interruptible(&tty->link->write_wait);
+        if (tty->driver->subtype == PTY_TYPE_MASTER) {
+                set_bit(TTY_OTHER_CLOSED, &tty->flags);
+#ifdef CONFIG_UNIX98_PTYS
+                if (tty->driver == ptm_driver)
+                        devpts_pty_kill(tty->index);
+#endif
+                tty_vhangup(tty->link);
+        }
+}
+
+/*
+ * The unthrottle routine is called by the line discipline to signal
+ * that it can receive more characters.  For PTY's, the TTY_THROTTLED
+ * flag is always set, to force the line discipline to always call the
+ * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE 
+ * characters in the queue.  This is necessary since each time this
+ * happens, we need to wake up any sleeping processes that could be
+ * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
+ * for the pty buffer to be drained.
+ */
+static void pty_unthrottle(struct tty_struct * tty)
+{
+        struct tty_struct *o_tty = tty->link;
+
+        if (!o_tty)
+                return;
+
+        tty_wakeup(o_tty);
+        set_bit(TTY_THROTTLED, &tty->flags);
+}
+
+/*
+ * WSH 05/24/97: modified to 
+ *   (1) use space in tty->flip instead of a shared temp buffer
+ *       The flip buffers aren't being used for a pty, so there's lots
+ *       of space available.  The buffer is protected by a per-pty
+ *       semaphore that should almost never come under contention.
+ *   (2) avoid redundant copying for cases where count >> receive_room
+ * N.B. Calls from user space may now return an error code instead of
+ * a count.
+ *
+ * FIXME: Our pty_write method is called with our ldisc lock held but
+ * not our partners. We can't just take the other one blindly without
+ * risking deadlocks.  There is also the small matter of TTY_DONT_FLIP
+ */
+static int pty_write(struct tty_struct * tty, const unsigned char *buf, int count)
+{
+        struct tty_struct *to = tty->link;
+        int     c;
+
+        if (!to || tty->stopped)
+                return 0;
+
+        c = to->ldisc.receive_room(to);
+        if (c > count)
+                c = count;
+        to->ldisc.receive_buf(to, buf, NULL, c);
+        
+        return c;
+}
+
+static int pty_write_room(struct tty_struct *tty)
+{
+        struct tty_struct *to = tty->link;
+
+        if (!to || tty->stopped)
+                return 0;
+
+        return to->ldisc.receive_room(to);
+}
+
+/*
+ *      WSH 05/24/97:  Modified for asymmetric MASTER/SLAVE behavior
+ *      The chars_in_buffer() value is used by the ldisc select() function 
+ *      to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
+ *      The pty driver chars_in_buffer() Master/Slave must behave differently:
+ *
+ *      The Master side needs to allow typed-ahead commands to accumulate
+ *      while being canonicalized, so we report "our buffer" as empty until
+ *      some threshold is reached, and then report the count. (Any count >
+ *      WAKEUP_CHARS is regarded by select() as "full".)  To avoid deadlock 
+ *      the count returned must be 0 if no canonical data is available to be 
+ *      read. (The N_TTY ldisc.chars_in_buffer now knows this.)
+ *  
+ *      The Slave side passes all characters in raw mode to the Master side's
+ *      buffer where they can be read immediately, so in this case we can
+ *      return the true count in the buffer.
+ */
+static int pty_chars_in_buffer(struct tty_struct *tty)
+{
+        struct tty_struct *to = tty->link;
+        ssize_t (*chars_in_buffer)(struct tty_struct *);
+        int count;
+
+        /* We should get the line discipline lock for "tty->link" */
+        if (!to || !(chars_in_buffer = to->ldisc.chars_in_buffer))
+                return 0;
+
+        /* The ldisc must report 0 if no characters available to be read */
+        count = chars_in_buffer(to);
+
+        if (tty->driver->subtype == PTY_TYPE_SLAVE) return count;
+
+        /* Master side driver ... if the other side's read buffer is less than 
+         * half full, return 0 to allow writers to proceed; otherwise return
+         * the count.  This leaves a comfortable margin to avoid overflow, 
+         * and still allows half a buffer's worth of typed-ahead commands.
+         */
+        return ((count < N_TTY_BUF_SIZE/2) ? 0 : count);
+}
+
+/* Set the lock flag on a pty */
+static int pty_set_lock(struct tty_struct *tty, int __user * arg)
+{
+        int val;
+        if (get_user(val,arg))
+                return -EFAULT;
+        if (val)
+                set_bit(TTY_PTY_LOCK, &tty->flags);
+        else
+                clear_bit(TTY_PTY_LOCK, &tty->flags);
+        return 0;
+}
+
+static void pty_flush_buffer(struct tty_struct *tty)
+{
+        struct tty_struct *to = tty->link;
+        
+        if (!to)
+                return;
+        
+        if (to->ldisc.flush_buffer)
+                to->ldisc.flush_buffer(to);
+        
+        if (to->packet) {
+                tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
+                wake_up_interruptible(&to->read_wait);
+        }
+}
+
+static int pty_open(struct tty_struct *tty, struct file * filp)
+{
+        int     retval = -ENODEV;
+
+        if (!tty || !tty->link)
+                goto out;
+
+        retval = -EIO;
+        if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
+                goto out;
+        if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
+                goto out;
+        if (tty->link->count != 1)
+                goto out;
+
+        clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
+        set_bit(TTY_THROTTLED, &tty->flags);
+        set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+        retval = 0;
+out:
+        return retval;
+}
+
+static void pty_set_termios(struct tty_struct *tty, struct termios *old_termios)
+{
+        tty->termios->c_cflag &= ~(CSIZE | PARENB);
+        tty->termios->c_cflag |= (CS8 | CREAD);
+}
+
+static struct tty_operations pty_ops = {
+        .open = pty_open,
+        .close = pty_close,
+        .write = pty_write,
+        .write_room = pty_write_room,
+        .flush_buffer = pty_flush_buffer,
+        .chars_in_buffer = pty_chars_in_buffer,
+        .unthrottle = pty_unthrottle,
+        .set_termios = pty_set_termios,
+};
+
+/* Traditional BSD devices */
+#ifdef CONFIG_LEGACY_PTYS
+static struct tty_driver *pty_driver, *pty_slave_driver;
+
+static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
+                         unsigned int cmd, unsigned long arg)
+{
+        switch (cmd) {
+        case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
+                return pty_set_lock(tty, (int __user *) arg);
+        }
+        return -ENOIOCTLCMD;
+}
+
+static void __init legacy_pty_init(void)
+{
+
+        pty_driver = alloc_tty_driver(NR_PTYS);
+        if (!pty_driver)
+                panic("Couldn't allocate pty driver");
+
+        pty_slave_driver = alloc_tty_driver(NR_PTYS);
+        if (!pty_slave_driver)
+                panic("Couldn't allocate pty slave driver");
+
+        pty_driver->owner = THIS_MODULE;
+        pty_driver->driver_name = "pty_master";
+        pty_driver->name = "pty";
+        pty_driver->devfs_name = "pty/m";
+        pty_driver->major = PTY_MASTER_MAJOR;
+        pty_driver->minor_start = 0;
+        pty_driver->type = TTY_DRIVER_TYPE_PTY;
+        pty_driver->subtype = PTY_TYPE_MASTER;
+        pty_driver->init_termios = tty_std_termios;
+        pty_driver->init_termios.c_iflag = 0;
+        pty_driver->init_termios.c_oflag = 0;
+        pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+        pty_driver->init_termios.c_lflag = 0;
+        pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
+        pty_driver->other = pty_slave_driver;
+        tty_set_operations(pty_driver, &pty_ops);
+        pty_driver->ioctl = pty_bsd_ioctl;
+
+        pty_slave_driver->owner = THIS_MODULE;
+        pty_slave_driver->driver_name = "pty_slave";
+        pty_slave_driver->name = "ttyp";
+        pty_slave_driver->devfs_name = "pty/s";
+        pty_slave_driver->major = PTY_SLAVE_MAJOR;
+        pty_slave_driver->minor_start = 0;
+        pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
+        pty_slave_driver->subtype = PTY_TYPE_SLAVE;
+        pty_slave_driver->init_termios = tty_std_termios;
+        pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+        pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
+                                        TTY_DRIVER_REAL_RAW;
+        pty_slave_driver->other = pty_driver;
+        tty_set_operations(pty_slave_driver, &pty_ops);
+
+        if (tty_register_driver(pty_driver))
+                panic("Couldn't register pty driver");
+        if (tty_register_driver(pty_slave_driver))
+                panic("Couldn't register pty slave driver");
+}
+#else
+static inline void legacy_pty_init(void) { }
+#endif
+
+/* Unix98 devices */
+#ifdef CONFIG_UNIX98_PTYS
+/*
+ * sysctl support for setting limits on the number of Unix98 ptys allocated.
+ * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
+ */
+int pty_limit = NR_UNIX98_PTY_DEFAULT;
+static int pty_limit_min = 0;
+static int pty_limit_max = NR_UNIX98_PTY_MAX;
+
+ctl_table pty_table[] = {
+        {
+                .ctl_name       = PTY_MAX,
+                .procname       = "max",
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .data           = &pty_limit,
+                .proc_handler   = &proc_dointvec_minmax,
+                .strategy       = &sysctl_intvec,
+                .extra1         = &pty_limit_min,
+                .extra2         = &pty_limit_max,
+        }, {
+                .ctl_name       = PTY_NR,
+                .procname       = "nr",
+                .maxlen         = sizeof(int),
+                .mode           = 0444,
+                .proc_handler   = &proc_dointvec,
+        }, {
+                .ctl_name       = 0
+        }
+};
+
+static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
+                            unsigned int cmd, unsigned long arg)
+{
+        switch (cmd) {
+        case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
+                return pty_set_lock(tty, (int __user *)arg);
+        case TIOCGPTN: /* Get PT Number */
+                return put_user(tty->index, (unsigned int __user *)arg);
+        }
+
+        return -ENOIOCTLCMD;
+}
+
+static void __init unix98_pty_init(void)
+{
+        devfs_mk_dir("pts");
+        ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
+        if (!ptm_driver)
+                panic("Couldn't allocate Unix98 ptm driver");
+        pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
+        if (!pts_driver)
+                panic("Couldn't allocate Unix98 pts driver");
+
+        ptm_driver->owner = THIS_MODULE;
+        ptm_driver->driver_name = "pty_master";
+        ptm_driver->name = "ptm";
+        ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
+        ptm_driver->minor_start = 0;
+        ptm_driver->type = TTY_DRIVER_TYPE_PTY;
+        ptm_driver->subtype = PTY_TYPE_MASTER;
+        ptm_driver->init_termios = tty_std_termios;
+        ptm_driver->init_termios.c_iflag = 0;
+        ptm_driver->init_termios.c_oflag = 0;
+        ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+        ptm_driver->init_termios.c_lflag = 0;
+        ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+                TTY_DRIVER_NO_DEVFS | TTY_DRIVER_DEVPTS_MEM;
+        ptm_driver->other = pts_driver;
+        tty_set_operations(ptm_driver, &pty_ops);
+        ptm_driver->ioctl = pty_unix98_ioctl;
+
+        pts_driver->owner = THIS_MODULE;
+        pts_driver->driver_name = "pty_slave";
+        pts_driver->name = "pts";
+        pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
+        pts_driver->minor_start = 0;
+        pts_driver->type = TTY_DRIVER_TYPE_PTY;
+        pts_driver->subtype = PTY_TYPE_SLAVE;
+        pts_driver->init_termios = tty_std_termios;
+        pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
+        pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+                TTY_DRIVER_NO_DEVFS | TTY_DRIVER_DEVPTS_MEM;
+        pts_driver->other = ptm_driver;
+        tty_set_operations(pts_driver, &pty_ops);
+        
+        if (tty_register_driver(ptm_driver))
+                panic("Couldn't register Unix98 ptm driver");
+        if (tty_register_driver(pts_driver))
+                panic("Couldn't register Unix98 pts driver");
+
+        pty_table[1].data = &ptm_driver->refcount;
+}
+#else
+static inline void unix98_pty_init(void) { }
+#endif
+
+static int __init pty_init(void)
+{
+        legacy_pty_init();
+        unix98_pty_init();
+        return 0;
+}
+module_init(pty_init);