diff options
Diffstat (limited to 'drivers/char/tty_io.c')
| -rw-r--r-- | drivers/char/tty_io.c | 234 |
1 files changed, 140 insertions, 94 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index d71f0fc34b46..949067a0bd47 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -136,6 +136,9 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ DEFINE_MUTEX(tty_mutex); EXPORT_SYMBOL(tty_mutex); +/* Spinlock to protect the tty->tty_files list */ +DEFINE_SPINLOCK(tty_files_lock); + static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); ssize_t redirected_tty_write(struct file *, const char __user *, @@ -149,6 +152,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, #else #define tty_compat_ioctl NULL #endif +static int __tty_fasync(int fd, struct file *filp, int on); static int tty_fasync(int fd, struct file *filp, int on); static void release_tty(struct tty_struct *tty, int idx); static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); @@ -184,6 +188,41 @@ void free_tty_struct(struct tty_struct *tty) kfree(tty); } +static inline struct tty_struct *file_tty(struct file *file) +{ + return ((struct tty_file_private *)file->private_data)->tty; +} + +/* Associate a new file with the tty structure */ +void tty_add_file(struct tty_struct *tty, struct file *file) +{ + struct tty_file_private *priv; + + /* XXX: must implement proper error handling in callers */ + priv = kmalloc(sizeof(*priv), GFP_KERNEL|__GFP_NOFAIL); + + priv->tty = tty; + priv->file = file; + file->private_data = priv; + + spin_lock(&tty_files_lock); + list_add(&priv->list, &tty->tty_files); + spin_unlock(&tty_files_lock); +} + +/* Delete file from its tty */ +void tty_del_file(struct file *file) +{ + struct tty_file_private *priv = file->private_data; + + spin_lock(&tty_files_lock); + list_del(&priv->list); + spin_unlock(&tty_files_lock); + file->private_data = NULL; + kfree(priv); +} + + #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) /** @@ -234,11 +273,11 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) struct list_head *p; int count = 0; - file_list_lock(); + spin_lock(&tty_files_lock); list_for_each(p, &tty->tty_files) { count++; } - file_list_unlock(); + spin_unlock(&tty_files_lock); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_SLAVE && tty->link && tty->link->count) @@ -470,7 +509,7 @@ void tty_wakeup(struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_wakeup); /** - * do_tty_hangup - actual handler for hangup events + * __tty_hangup - actual handler for hangup events * @work: tty device * * This can be called by the "eventd" kernel thread. That is process @@ -483,7 +522,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup); * remains intact. * * Locking: - * BKL + * BTM * redirect lock for undoing redirection * file list lock for manipulating list of ttys * tty_ldisc_lock from called functions @@ -491,13 +530,12 @@ EXPORT_SYMBOL_GPL(tty_wakeup); * tasklist_lock to walk task list for hangup event * ->siglock to protect ->signal/->sighand */ -static void do_tty_hangup(struct work_struct *work) +void __tty_hangup(struct tty_struct *tty) { - struct tty_struct *tty = - container_of(work, struct tty_struct, hangup_work); struct file *cons_filp = NULL; struct file *filp, *f = NULL; struct task_struct *p; + struct tty_file_private *priv; int closecount = 0, n; unsigned long flags; int refs = 0; @@ -507,28 +545,32 @@ static void do_tty_hangup(struct work_struct *work) spin_lock(&redirect_lock); - if (redirect && redirect->private_data == tty) { + if (redirect && file_tty(redirect) == tty) { f = redirect; redirect = NULL; } spin_unlock(&redirect_lock); - /* inuse_filps is protected by the single kernel lock */ - lock_kernel(); - check_tty_count(tty, "do_tty_hangup"); + tty_lock(); + + /* inuse_filps is protected by the single tty lock, + this really needs to change if we want to flush the + workqueue with the lock held */ + check_tty_count(tty, "tty_hangup"); - file_list_lock(); + spin_lock(&tty_files_lock); /* This breaks for file handles being sent over AF_UNIX sockets ? */ - list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { + list_for_each_entry(priv, &tty->tty_files, list) { + filp = priv->file; if (filp->f_op->write == redirected_tty_write) cons_filp = filp; if (filp->f_op->write != tty_write) continue; closecount++; - tty_fasync(-1, filp, 0); /* can't block */ + __tty_fasync(-1, filp, 0); /* can't block */ filp->f_op = &hung_up_tty_fops; } - file_list_unlock(); + spin_unlock(&tty_files_lock); tty_ldisc_hangup(tty); @@ -594,11 +636,21 @@ static void do_tty_hangup(struct work_struct *work) */ set_bit(TTY_HUPPED, &tty->flags); tty_ldisc_enable(tty); - unlock_kernel(); + + tty_unlock(); + if (f) fput(f); } +static void do_tty_hangup(struct work_struct *work) +{ + struct tty_struct *tty = + container_of(work, struct tty_struct, hangup_work); + + __tty_hangup(tty); +} + /** * tty_hangup - trigger a hangup event * @tty: tty to hangup @@ -634,11 +686,12 @@ void tty_vhangup(struct tty_struct *tty) printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); #endif - do_tty_hangup(&tty->hangup_work); + __tty_hangup(tty); } EXPORT_SYMBOL(tty_vhangup); + /** * tty_vhangup_self - process vhangup for own ctty * @@ -696,7 +749,8 @@ static void session_clear_tty(struct pid *session) * exiting; it is 0 if called by the ioctl TIOCNOTTY. * * Locking: - * BKL is taken for hysterical raisins + * BTM is taken for hysterical raisins, and held when + * called from no_tty(). * tty_mutex is taken to protect tty * ->siglock is taken to protect ->signal/->sighand * tasklist_lock is taken to walk process list for sessions @@ -714,10 +768,10 @@ void disassociate_ctty(int on_exit) tty = get_current_tty(); if (tty) { tty_pgrp = get_pid(tty->pgrp); - lock_kernel(); - if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) - tty_vhangup(tty); - unlock_kernel(); + if (on_exit) { + if (tty->driver->type != TTY_DRIVER_TYPE_PTY) + tty_vhangup(tty); + } tty_kref_put(tty); } else if (on_exit) { struct pid *old_pgrp; @@ -774,9 +828,9 @@ void disassociate_ctty(int on_exit) void no_tty(void) { struct task_struct *tsk = current; - lock_kernel(); + tty_lock(); disassociate_ctty(0); - unlock_kernel(); + tty_unlock(); proc_clear_tty(tsk); } @@ -875,12 +929,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int i; - struct tty_struct *tty; - struct inode *inode; + struct inode *inode = file->f_path.dentry->d_inode; + struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; - tty = (struct tty_struct *)file->private_data; - inode = file->f_path.dentry->d_inode; if (tty_paranoia_check(tty, inode, "tty_read")) return -EIO; if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) @@ -1013,19 +1065,19 @@ out: * We don't put it into the syslog queue right now maybe in the future if * really needed. * - * We must still hold the BKL and test the CLOSING flag for the moment. + * We must still hold the BTM and test the CLOSING flag for the moment. */ void tty_write_message(struct tty_struct *tty, char *msg) { if (tty) { mutex_lock(&tty->atomic_write_lock); - lock_kernel(); + tty_lock(); if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) { - unlock_kernel(); + tty_unlock(); tty->ops->write(tty, msg, strlen(msg)); } else - unlock_kernel(); + tty_unlock(); tty_write_unlock(tty); } return; @@ -1051,12 +1103,11 @@ void tty_write_message(struct tty_struct *tty, char *msg) static ssize_t tty_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - struct tty_struct *tty; struct inode *inode = file->f_path.dentry->d_inode; + struct tty_struct *tty = file_tty(file); + struct tty_ldisc *ld; ssize_t ret; - struct tty_ldisc *ld; - tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_write")) return -EIO; if (!tty || !tty->ops->write || @@ -1208,18 +1259,14 @@ static int tty_driver_install_tty(struct tty_driver *driver, int ret; if (driver->ops->install) { - lock_kernel(); ret = driver->ops->install(driver, tty); - unlock_kernel(); return ret; } if (tty_init_termios(tty) == 0) { - lock_kernel(); tty_driver_kref_get(driver); tty->count++; driver->ttys[idx] = tty; - unlock_kernel(); return 0; } return -ENOMEM; @@ -1312,14 +1359,11 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, struct tty_struct *tty; int retval; - lock_kernel(); /* Check if pty master is being opened multiple times */ if (driver->subtype == PTY_TYPE_MASTER && (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) { - unlock_kernel(); return ERR_PTR(-EIO); } - unlock_kernel(); /* * First time open is complex, especially for PTY devices. @@ -1363,9 +1407,7 @@ release_mem_out: if (printk_ratelimit()) printk(KERN_INFO "tty_init_dev: ldisc open failed, " "clearing slot %d\n", idx); - lock_kernel(); release_tty(tty, idx); - unlock_kernel(); return ERR_PTR(retval); } @@ -1419,9 +1461,9 @@ static void release_one_tty(struct work_struct *work) tty_driver_kref_put(driver); module_put(driver->owner); - file_list_lock(); + spin_lock(&tty_files_lock); list_del_init(&tty->tty_files); - file_list_unlock(); + spin_unlock(&tty_files_lock); put_pid(tty->pgrp); put_pid(tty->session); @@ -1502,20 +1544,20 @@ static void release_tty(struct tty_struct *tty, int idx) int tty_release(struct inode *inode, struct file *filp) { - struct tty_struct *tty, *o_tty; + struct tty_struct *tty = file_tty(filp); + struct tty_struct *o_tty; int pty_master, tty_closing, o_tty_closing, do_sleep; int devpts; int idx; char buf[64]; - tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, inode, "tty_release_dev")) return 0; - lock_kernel(); + tty_lock(); check_tty_count(tty, "tty_release_dev"); - tty_fasync(-1, filp, 0); + __tty_fasync(-1, filp, 0); idx = tty->index; pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && @@ -1527,18 +1569,18 @@ int tty_release(struct inode *inode, struct file *filp) if (idx < 0 || idx >= tty->driver->num) { printk(KERN_DEBUG "tty_release_dev: bad idx when trying to " "free (%s)\n", tty->name); - unlock_kernel(); + tty_unlock(); return 0; } if (!devpts) { if (tty != tty->driver->ttys[idx]) { - unlock_kernel(); + tty_unlock(); printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty " "for (%s)\n", idx, tty->name); return 0; } if (tty->termios != tty->driver->termios[idx]) { - unlock_kernel(); + tty_unlock(); printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios " "for (%s)\n", idx, tty->name); @@ -1556,21 +1598,21 @@ int tty_release(struct inode *inode, struct file *filp) if (tty->driver->other && !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { if (o_tty != tty->driver->other->ttys[idx]) { - unlock_kernel(); + tty_unlock(); printk(KERN_DEBUG "tty_release_dev: other->table[%d] " "not o_tty for (%s)\n", idx, tty->name); return 0 ; } if (o_tty->termios != tty->driver->other->termios[idx]) { - unlock_kernel(); + tty_unlock(); printk(KERN_DEBUG "tty_release_dev: other->termios[%d] " "not o_termios for (%s)\n", idx, tty->name); return 0; } if (o_tty->link != tty) { - unlock_kernel(); + tty_unlock(); printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n"); return 0; } @@ -1579,7 +1621,7 @@ int tty_release(struct inode *inode, struct file *filp) if (tty->ops->close) tty->ops->close(tty, filp); - unlock_kernel(); + tty_unlock(); /* * Sanity check: if tty->count is going to zero, there shouldn't be * any waiters on tty->read_wait or tty->write_wait. We test the @@ -1602,7 +1644,7 @@ int tty_release(struct inode *inode, struct file *filp) opens on /dev/tty */ mutex_lock(&tty_mutex); - lock_kernel(); + tty_lock(); tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); @@ -1633,7 +1675,7 @@ int tty_release(struct inode *inode, struct file *filp) printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue " "active!\n", tty_name(tty, buf)); - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); schedule(); } @@ -1666,8 +1708,7 @@ int tty_release(struct inode *inode, struct file *filp) * - do_tty_hangup no longer sees this file descriptor as * something that needs to be handled for hangups. */ - file_kill(filp); - filp->private_data = NULL; + tty_del_file(filp); /* * Perform some housekeeping before deciding whether to return. @@ -1698,7 +1739,7 @@ int tty_release(struct inode *inode, struct file *filp) /* check whether both sides are closing ... */ if (!tty_closing || (o_tty && !o_tty_closing)) { - unlock_kernel(); + tty_unlock(); return 0; } @@ -1718,7 +1759,7 @@ int tty_release(struct inode *inode, struct file *filp) /* Make this pty number available for reallocation */ if (devpts) devpts_kill_index(inode, idx); - unlock_kernel(); + tty_unlock(); return 0; } @@ -1760,12 +1801,12 @@ retry_open: retval = 0; mutex_lock(&tty_mutex); - lock_kernel(); + tty_lock(); if (device == MKDEV(TTYAUX_MAJOR, 0)) { tty = get_current_tty(); if (!tty) { - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); return -ENXIO; } @@ -1797,14 +1838,14 @@ retry_open: goto got_driver; } } - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); return -ENODEV; } driver = get_tty_driver(device, &index); if (!driver) { - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); return -ENODEV; } @@ -1814,7 +1855,7 @@ got_driver: tty = tty_driver_lookup_tty(driver, inode, index); if (IS_ERR(tty)) { - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); return PTR_ERR(tty); } @@ -1830,12 +1871,12 @@ got_driver: mutex_unlock(&tty_mutex); tty_driver_kref_put(driver); if (IS_ERR(tty)) { - unlock_kernel(); + tty_unlock(); return PTR_ERR(tty); } - filp->private_data = tty; - file_move(filp, &tty->tty_files); + tty_add_file(tty, filp); + check_tty_count(tty, "tty_open"); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) @@ -1860,29 +1901,29 @@ got_driver: printk(KERN_DEBUG "error %d in opening %s...", retval, tty->name); #endif + tty_unlock(); /* need to call tty_release without BTM */ tty_release(inode, filp); - if (retval != -ERESTARTSYS) { - unlock_kernel(); + if (retval != -ERESTARTSYS) return retval; - } - if (signal_pending(current)) { - unlock_kernel(); + + if (signal_pending(current)) return retval; - } + schedule(); /* * Need to reset f_op in case a hangup happened. */ + tty_lock(); if (filp->f_op == &hung_up_tty_fops) filp->f_op = &tty_fops; - unlock_kernel(); + tty_unlock(); goto retry_open; } - unlock_kernel(); + tty_unlock(); mutex_lock(&tty_mutex); - lock_kernel(); + tty_lock(); spin_lock_irq(¤t->sighand->siglock); if (!noctty && current->signal->leader && @@ -1890,7 +1931,7 @@ got_driver: tty->session == NULL) __proc_set_tty(current, tty); spin_unlock_irq(¤t->sighand->siglock); - unlock_kernel(); + tty_unlock(); mutex_unlock(&tty_mutex); return 0; } @@ -1911,11 +1952,10 @@ got_driver: static unsigned int tty_poll(struct file *filp, poll_table *wait) { - struct tty_struct *tty; + struct tty_struct *tty = file_tty(filp); struct tty_ldisc *ld; int ret = 0; - tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) return 0; @@ -1926,14 +1966,12 @@ static unsigned int tty_poll(struct file *filp, poll_table *wait) return ret; } -static int tty_fasync(int fd, struct file *filp, int on) +static int __tty_fasync(int fd, struct file *filp, int on) { - struct tty_struct *tty; + struct tty_struct *tty = file_tty(filp); unsigned long flags; int retval = 0; - lock_kernel(); - tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) goto out; @@ -1966,7 +2004,15 @@ static int tty_fasync(int fd, struct file *filp, int on) } retval = 0; out: - unlock_kernel(); + return retval; +} + +static int tty_fasync(int fd, struct file *filp, int on) +{ + int retval; + tty_lock(); + retval = __tty_fasync(fd, filp, on); + tty_unlock(); return retval; } @@ -2479,13 +2525,13 @@ EXPORT_SYMBOL(tty_pair_get_pty); */ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct tty_struct *tty, *real_tty; + struct tty_struct *tty = file_tty(file); + struct tty_struct *real_tty; void __user *p = (void __user *)arg; int retval; struct tty_ldisc *ld; struct inode *inode = file->f_dentry->d_inode; - tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_ioctl")) return -EINVAL; @@ -2607,7 +2653,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct inode *inode = file->f_dentry->d_inode; - struct tty_struct *tty = file->private_data; + struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; int retval = -ENOIOCTLCMD; @@ -2699,7 +2745,7 @@ void __do_SAK(struct tty_struct *tty) if (!filp) continue; if (filp->f_op->read == tty_read && - filp->private_data == tty) { + file_tty(filp) == tty) { printk(KERN_NOTICE "SAK: killed process %d" " (%s): fd#%d opened to the tty\n", task_pid_nr(p), p->comm, i); @@ -3128,7 +3174,7 @@ static struct cdev tty_cdev, console_cdev; * Ok, now we can initialize the rest of the tty devices and can count * on memory allocations, interrupts etc.. */ -static int __init tty_init(void) +int __init tty_init(void) { cdev_init(&tty_cdev, &tty_fops); if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || @@ -3149,4 +3195,4 @@ static int __init tty_init(void) #endif return 0; } -module_init(tty_init); + |