X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fchar%2Ftty_io.c;h=9691b8ea6d94d382b0c12396b13609bdea7cd0ff;hb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;hp=91f530c6170ee73ba76f3b12bfd517518289fcaa;hpb=9bf4aaab3e101692164d49b7ca357651eb691cb6;p=linux-2.6.git diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 91f530c61..9691b8ea6 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -92,6 +92,7 @@ #include #include #include +#include #include #include @@ -101,6 +102,7 @@ #include #include #include +#include #include @@ -120,10 +122,14 @@ struct termios tty_std_termios = { /* for the benefit of tty drivers */ EXPORT_SYMBOL(tty_std_termios); +/* This list gets poked at by procfs and various bits of boot up code. This + could do with some rationalisation such as pulling the tty proc function + into this file */ + LIST_HEAD(tty_drivers); /* linked list of tty drivers */ -struct tty_ldisc ldiscs[NR_LDISCS]; /* line disc dispatch table */ -/* Semaphore to protect creating and releasing a tty */ +/* Semaphore to protect creating and releasing a tty. This is shared with + vt.c for deeply disgusting hack reasons */ DECLARE_MUTEX(tty_sem); #ifdef CONFIG_UNIX98_PTYS @@ -142,6 +148,7 @@ static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); static unsigned int tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); +static int ptmx_open(struct inode *, struct file *); static int tty_release(struct inode *, struct file *); int tty_ioctl(struct inode * inode, struct file * file, unsigned int cmd, unsigned long arg); @@ -223,65 +230,323 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) return 0; } +/* + * This is probably overkill for real world processors but + * they are not on hot paths so a little discipline won't do + * any harm. + */ + +static void tty_set_termios_ldisc(struct tty_struct *tty, int num) +{ + down(&tty->termios_sem); + tty->termios->c_line = num; + up(&tty->termios_sem); +} + +/* + * This guards the refcounted line discipline lists. The lock + * must be taken with irqs off because there are hangup path + * callers who will do ldisc lookups and cannot sleep. + */ + +static spinlock_t tty_ldisc_lock = SPIN_LOCK_UNLOCKED; +static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); +static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ + int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) { + unsigned long flags; + int ret = 0; + if (disc < N_TTY || disc >= NR_LDISCS) return -EINVAL; + spin_lock_irqsave(&tty_ldisc_lock, flags); if (new_ldisc) { - ldiscs[disc] = *new_ldisc; - ldiscs[disc].flags |= LDISC_FLAG_DEFINED; - ldiscs[disc].num = disc; - } else - memset(&ldiscs[disc], 0, sizeof(struct tty_ldisc)); + tty_ldiscs[disc] = *new_ldisc; + tty_ldiscs[disc].num = disc; + tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; + tty_ldiscs[disc].refcount = 0; + } else { + if(tty_ldiscs[disc].refcount) + ret = -EBUSY; + else + tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); - return 0; + return ret; } EXPORT_SYMBOL(tty_register_ldisc); -/* Set the discipline of a tty line. */ +struct tty_ldisc *tty_ldisc_get(int disc) +{ + unsigned long flags; + struct tty_ldisc *ld; + + if (disc < N_TTY || disc >= NR_LDISCS) + return NULL; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + + ld = &tty_ldiscs[disc]; + /* Check the entry is defined */ + if(ld->flags & LDISC_FLAG_DEFINED) + { + /* If the module is being unloaded we can't use it */ + if (!try_module_get(ld->owner)) + ld = NULL; + else /* lock it */ + ld->refcount++; + } + else + ld = NULL; + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ld; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_get); + +void tty_ldisc_put(int disc) +{ + struct tty_ldisc *ld; + unsigned long flags; + + if (disc < N_TTY || disc >= NR_LDISCS) + BUG(); + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ld = &tty_ldiscs[disc]; + if(ld->refcount == 0) + BUG(); + ld->refcount --; + module_put(ld->owner); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +EXPORT_SYMBOL_GPL(tty_ldisc_put); + +void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) +{ + tty->ldisc = *ld; + tty->ldisc.refcount = 0; +} + +/** + * tty_ldisc_try - internal helper + * @tty: the tty + * + * Make a single attempt to grab and bump the refcount on + * the tty ldisc. Return 0 on failure or 1 on success. This is + * used to implement both the waiting and non waiting versions + * of tty_ldisc_ref + */ + +static int tty_ldisc_try(struct tty_struct *tty) +{ + unsigned long flags; + struct tty_ldisc *ld; + int ret = 0; + + spin_lock_irqsave(&tty_ldisc_lock, flags); + ld = &tty->ldisc; + if(test_bit(TTY_LDISC, &tty->flags)) + { + ld->refcount++; + ret = 1; + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + return ret; +} + +/** + * tty_ldisc_ref_wait - wait for the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * wait patiently until it changes. + * + * Note: Must not be called from an IRQ/timer context. The caller + * must also be careful not to hold other locks that will deadlock + * against a discipline change, such as an existing ldisc reference + * (which we check for) + */ + +struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) +{ + /* wait_event is a macro */ + wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); + if(tty->ldisc.refcount == 0) + printk(KERN_ERR "tty_ldisc_ref_wait\n"); + return &tty->ldisc; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); + +/** + * tty_ldisc_ref - get the tty ldisc + * @tty: tty device + * + * Dereference the line discipline for the terminal and take a + * reference to it. If the line discipline is in flux then + * return NULL. Can be called from IRQ and timer functions. + */ + +struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) +{ + if(tty_ldisc_try(tty)) + return &tty->ldisc; + return NULL; +} + +EXPORT_SYMBOL_GPL(tty_ldisc_ref); + +/** + * tty_ldisc_deref - free a tty ldisc reference + * @ld: reference to free up + * + * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May + * be called in IRQ context. + */ + +void tty_ldisc_deref(struct tty_ldisc *ld) +{ + unsigned long flags; + + if(ld == NULL) + BUG(); + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if(ld->refcount == 0) + printk(KERN_ERR "tty_ldisc_deref: no references.\n"); + else + ld->refcount--; + if(ld->refcount == 0) + wake_up(&tty_ldisc_wait); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); +} + +EXPORT_SYMBOL_GPL(tty_ldisc_deref); + +/** + * tty_ldisc_enable - allow ldisc use + * @tty: terminal to activate ldisc on + * + * Set the TTY_LDISC flag when the line discipline can be called + * again. Do neccessary wakeups for existing sleepers. + * + * Note: nobody should set this bit except via this function. Clearing + * directly is allowed. + */ + +static void tty_ldisc_enable(struct tty_struct *tty) +{ + set_bit(TTY_LDISC, &tty->flags); + wake_up(&tty_ldisc_wait); +} + +/** + * tty_set_ldisc - set line discipline + * @tty: the terminal to set + * @ldisc: the line discipline + * + * Set the discipline of a tty line. Must be called from a process + * context. + */ + static int tty_set_ldisc(struct tty_struct *tty, int ldisc) { int retval = 0; struct tty_ldisc o_ldisc; char buf[64]; + int work; + unsigned long flags; + struct tty_ldisc *ld; if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) return -EINVAL; + +restart: + + if (tty->ldisc.num == ldisc) + return 0; /* We are already in the desired discipline */ + + ld = tty_ldisc_get(ldisc); /* Eduardo Blanco */ /* Cyrus Durgin */ - if (!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED)) { + if (ld == NULL) { request_module("tty-ldisc-%d", ldisc); + ld = tty_ldisc_get(ldisc); } - if (!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED)) + if (ld == NULL) return -EINVAL; - if (tty->ldisc.num == ldisc) - return 0; /* We are already in the desired discipline */ - - if (!try_module_get(ldiscs[ldisc].owner)) - return -EINVAL; - o_ldisc = tty->ldisc; tty_wait_until_sent(tty, 0); + + /* + * Make sure we don't change while someone holds a + * reference to the line discipline. The TTY_LDISC bit + * prevents anyone taking a reference once it is clear. + * We need the lock to avoid racing reference takers. + */ + + spin_lock_irqsave(&tty_ldisc_lock, flags); + if(tty->ldisc.refcount) + { + /* Free the new ldisc we grabbed. Must drop the lock + first. */ + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + tty_ldisc_put(ldisc); + /* + * There are several reasons we may be busy, including + * random momentary I/O traffic. We must therefore + * retry. We could distinguish between blocking ops + * and retries if we made tty_ldisc_wait() smarter. That + * is up for discussion. + */ + if(wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) + return -ERESTARTSYS; + goto restart; + } + clear_bit(TTY_LDISC, &tty->flags); + clear_bit(TTY_DONT_FLIP, &tty->flags); + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + /* + * From this point on we know nobody has an ldisc + * usage reference, nor can they obtain one until + * we say so later on. + */ + + work = cancel_delayed_work(&tty->flip.work); + /* + * Wait for ->hangup_work and ->flip.work handlers to terminate + */ + + flush_scheduled_work(); /* Shutdown the current discipline. */ if (tty->ldisc.close) (tty->ldisc.close)(tty); /* Now set up the new line discipline. */ - tty->ldisc = ldiscs[ldisc]; - tty->termios->c_line = ldisc; + tty_ldisc_assign(tty, ld); + tty_set_termios_ldisc(tty, ldisc); if (tty->ldisc.open) retval = (tty->ldisc.open)(tty); if (retval < 0) { - tty->ldisc = o_ldisc; - tty->termios->c_line = tty->ldisc.num; + tty_ldisc_put(ldisc); + /* There is an outstanding reference here so this is safe */ + tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); + tty_set_termios_ldisc(tty, tty->ldisc.num); if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { - tty->ldisc = ldiscs[N_TTY]; - tty->termios->c_line = N_TTY; + tty_ldisc_put(o_ldisc.num); + /* This driver is always present */ + tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); + tty_set_termios_ldisc(tty, N_TTY); if (tty->ldisc.open) { int r = tty->ldisc.open(tty); @@ -291,12 +556,27 @@ static int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_name(tty, buf), r); } } - } else { - module_put(o_ldisc.owner); } + /* At this point we hold a reference to the new ldisc and a + a reference to the old ldisc. If we ended up flipping back + to the existing ldisc we have two references to it */ if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) tty->driver->set_ldisc(tty); + + tty_ldisc_put(o_ldisc.num); + + /* + * Allow ldisc referencing to occur as soon as the driver + * ldisc callback completes. + */ + + tty_ldisc_enable(tty); + + /* Restart it in case no characters kick it off. Safe if + already running */ + if(work) + schedule_delayed_work(&tty->flip.work, 1); return retval; } @@ -377,6 +657,19 @@ static struct file_operations tty_fops = { .fasync = tty_fasync, }; +#ifdef CONFIG_UNIX98_PTYS +static struct file_operations ptmx_fops = { + .llseek = no_llseek, + .read = tty_read, + .write = tty_write, + .poll = tty_poll, + .ioctl = tty_ioctl, + .open = ptmx_open, + .release = tty_release, + .fasync = tty_fasync, +}; +#endif + static struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, @@ -399,6 +692,53 @@ static struct file_operations hung_up_tty_fops = { static spinlock_t redirect_lock = SPIN_LOCK_UNLOCKED; static struct file *redirect; + +/** + * tty_wakeup - request more data + * @tty: terminal + * + * Internal and external helper for wakeups of tty. This function + * informs the line discipline if present that the driver is ready + * to receive more output data. + */ + +void tty_wakeup(struct tty_struct *tty) +{ + struct tty_ldisc *ld; + + if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { + ld = tty_ldisc_ref(tty); + if(ld) { + if(ld->write_wakeup) + ld->write_wakeup(tty); + tty_ldisc_deref(ld); + } + } + wake_up_interruptible(&tty->write_wait); +} + +EXPORT_SYMBOL_GPL(tty_wakeup); + +/** + * tty_ldisc_flush - flush line discipline queue + * @tty: tty + * + * Flush the line discipline queue (if any) for this tty. If there + * is no line discipline active this is a no-op. + */ + +void tty_ldisc_flush(struct tty_struct *tty) +{ + struct tty_ldisc *ld = tty_ldisc_ref(tty); + if(ld) { + if(ld->flush_buffer) + ld->flush_buffer(tty); + tty_ldisc_deref(ld); + } +} + +EXPORT_SYMBOL_GPL(tty_ldisc_flush); + /* * This can be called by the "eventd" kernel thread. That is process synchronous, * but doesn't hold any locks, so we need to make sure we have the appropriate @@ -410,7 +750,7 @@ void do_tty_hangup(void *data) struct file * cons_filp = NULL; struct file *filp, *f = NULL; struct task_struct *p; - struct pid *pid; + struct tty_ldisc *ld; int closecount = 0, n; if (!tty) @@ -428,6 +768,7 @@ void do_tty_hangup(void *data) check_tty_count(tty, "do_tty_hangup"); file_list_lock(); + /* This breaks for file handles being sent over AF_UNIX sockets ? */ list_for_each_entry(filp, &tty->tty_files, f_list) { if (filp->f_op->write == redirected_tty_write) cons_filp = filp; @@ -440,21 +781,25 @@ void do_tty_hangup(void *data) file_list_unlock(); /* FIXME! What are the locking issues here? This may me overdoing things.. - * this question is especially important now that we've removed the irqlock. */ - { - unsigned long flags; + * this question is especially important now that we've removed the irqlock. */ - local_irq_save(flags); // FIXME: is this safe? - if (tty->ldisc.flush_buffer) - tty->ldisc.flush_buffer(tty); + ld = tty_ldisc_ref(tty); + if(ld != NULL) /* We may have no line discipline at this point */ + { + if (ld->flush_buffer) + ld->flush_buffer(tty); if (tty->driver->flush_buffer) tty->driver->flush_buffer(tty); if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && - tty->ldisc.write_wakeup) - (tty->ldisc.write_wakeup)(tty); - local_irq_restore(flags); // FIXME: is this safe? + ld->write_wakeup) + ld->write_wakeup(tty); + if (ld->hangup) + ld->hangup(tty); } + /* FIXME: Once we trust the LDISC code better we can wait here for + ldisc completion and fix the driver call race */ + wake_up_interruptible(&tty->write_wait); wake_up_interruptible(&tty->read_wait); @@ -463,26 +808,21 @@ void do_tty_hangup(void *data) * N_TTY. */ if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) + { + down(&tty->termios_sem); *tty->termios = tty->driver->init_termios; - if (tty->ldisc.num != ldiscs[N_TTY].num) { - if (tty->ldisc.close) - (tty->ldisc.close)(tty); - module_put(tty->ldisc.owner); - - tty->ldisc = ldiscs[N_TTY]; - tty->termios->c_line = N_TTY; - if (tty->ldisc.open) { - int i = (tty->ldisc.open)(tty); - if (i < 0) - printk(KERN_ERR "do_tty_hangup: N_TTY open: " - "error %d\n", -i); - } + up(&tty->termios_sem); } + /* Defer ldisc switch */ + /* tty_deferred_ldisc_switch(N_TTY); + + This should get done automatically when the port closes and + tty_release is called */ + read_lock(&tasklist_lock); if (tty->session > 0) { - struct list_head *l; - for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid) { + do_each_task_pid(tty->session, PIDTYPE_SID, p) { if (p->signal->tty == tty) p->signal->tty = NULL; if (!p->signal->leader) @@ -491,7 +831,7 @@ void do_tty_hangup(void *data) send_group_sig_info(SIGCONT, SEND_SIG_PRIV, p); if (tty->pgrp > 0) p->signal->tty_old_pgrp = tty->pgrp; - } + } while_each_task_pid(tty->session, PIDTYPE_SID, p); } read_unlock(&tasklist_lock); @@ -511,6 +851,17 @@ void do_tty_hangup(void *data) tty->driver->close(tty, cons_filp); } else if (tty->driver->hangup) (tty->driver->hangup)(tty); + + /* We don't want to have driver/ldisc interactions beyond + the ones we did here. The driver layer expects no + calls after ->hangup() from the ldisc side. However we + can't yet guarantee all that */ + + set_bit(TTY_HUPPED, &tty->flags); + if (ld) { + tty_ldisc_enable(tty); + tty_ldisc_deref(ld); + } unlock_kernel(); if (f) fput(f); @@ -563,8 +914,6 @@ void disassociate_ctty(int on_exit) { struct tty_struct *tty; struct task_struct *p; - struct list_head *l; - struct pid *pid; int tty_pgrp = -1; lock_kernel(); @@ -593,8 +942,9 @@ void disassociate_ctty(int on_exit) tty->pgrp = -1; read_lock(&tasklist_lock); - for_each_task_pid(current->signal->session, PIDTYPE_SID, p, l, pid) + do_each_task_pid(current->signal->session, PIDTYPE_SID, p) { p->signal->tty = NULL; + } while_each_task_pid(current->signal->session, PIDTYPE_SID, p); read_unlock(&tasklist_lock); unlock_kernel(); } @@ -627,9 +977,9 @@ void start_tty(struct tty_struct *tty) } if (tty->driver->start) (tty->driver->start)(tty); - if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && - tty->ldisc.write_wakeup) - (tty->ldisc.write_wakeup)(tty); + + /* If we have a running line discipline it may need kicking */ + tty_wakeup(tty); wake_up_interruptible(&tty->write_wait); } @@ -641,6 +991,7 @@ static ssize_t tty_read(struct file * file, char __user * buf, size_t count, int i; struct tty_struct * tty; struct inode *inode; + struct tty_ldisc *ld; tty = (struct tty_struct *)file->private_data; inode = file->f_dentry->d_inode; @@ -649,11 +1000,15 @@ static ssize_t tty_read(struct file * file, char __user * buf, size_t count, if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) return -EIO; + /* We want to wait for the line discipline to sort out in this + situation */ + ld = tty_ldisc_ref_wait(tty); lock_kernel(); - if (tty->ldisc.read) - i = (tty->ldisc.read)(tty,file,buf,count); + if (ld->read) + i = (ld->read)(tty,file,buf,count); else i = -EIO; + tty_ldisc_deref(ld); unlock_kernel(); if (i > 0) inode->i_atime = CURRENT_TIME; @@ -715,16 +1070,23 @@ static ssize_t tty_write(struct file * file, const char __user * buf, size_t cou { struct tty_struct * tty; struct inode *inode = file->f_dentry->d_inode; - + 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->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) return -EIO; - if (!tty->ldisc.write) - return -EIO; - return do_tty_write(tty->ldisc.write, tty, file, + + ld = tty_ldisc_ref_wait(tty); + if (!ld->write) + ret = -EIO; + else + ret = do_tty_write(ld->write, tty, file, (const unsigned char __user *)buf, count); + tty_ldisc_deref(ld); + return ret; } ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, @@ -749,6 +1111,17 @@ ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t return tty_write(file, buf, count, ppos); } +static char ptychar[] = "pqrstuvwxyzabcde"; + +static inline void pty_line_name(struct tty_driver *driver, int index, char *p) +{ + int i = index + driver->name_base; + /* ->name is initialized to "ttyp", but "tty" is expected */ + sprintf(p, "%s%c%x", + driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, + ptychar[i >> 4 & 0xf], i & 0xf); +} + static inline void tty_line_name(struct tty_driver *driver, int index, char *p) { sprintf(p, "%s%d", driver->name, index + driver->name_base); @@ -910,6 +1283,7 @@ static int init_dev(struct tty_driver *driver, int idx, * If we fail here just call release_mem to clean up. No need * to decrement the use counts, as release_mem doesn't care. */ + if (tty->ldisc.open) { retval = (tty->ldisc.open)(tty); if (retval) @@ -922,7 +1296,9 @@ static int init_dev(struct tty_driver *driver, int idx, (tty->ldisc.close)(tty); goto release_mem_out; } + tty_ldisc_enable(o_tty); } + tty_ldisc_enable(tty); goto success; /* @@ -951,6 +1327,9 @@ fast_track: tty->count++; tty->driver = driver; /* N.B. why do this every time?? */ + /* FIXME */ + if(!test_bit(TTY_LDISC, &tty->flags)) + printk(KERN_ERR "init_dev but no ldisc\n"); success: *ret_tty = tty; @@ -1054,6 +1433,7 @@ static void release_dev(struct file * filp) int devpts_master, devpts; int idx; char buf[64]; + unsigned long flags; tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "release_dev")) @@ -1130,7 +1510,6 @@ static void release_dev(struct file * filp) } } #endif - if (tty->driver->close) tty->driver->close(tty, filp); @@ -1235,15 +1614,15 @@ static void release_dev(struct file * filp) */ if (tty_closing || o_tty_closing) { struct task_struct *p; - struct list_head *l; - struct pid *pid; read_lock(&tasklist_lock); - for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid) + do_each_task_pid(tty->session, PIDTYPE_SID, p) { p->signal->tty = NULL; + } while_each_task_pid(tty->session, PIDTYPE_SID, p); if (o_tty) - for_each_task_pid(o_tty->session, PIDTYPE_SID, p,l, pid) + do_each_task_pid(o_tty->session, PIDTYPE_SID, p) { p->signal->tty = NULL; + } while_each_task_pid(o_tty->session, PIDTYPE_SID, p); read_unlock(&tasklist_lock); } @@ -1254,36 +1633,58 @@ static void release_dev(struct file * filp) #ifdef TTY_DEBUG_HANGUP printk(KERN_DEBUG "freeing tty structure..."); #endif - /* * Prevent flush_to_ldisc() from rescheduling the work for later. Then - * kill any delayed work. + * kill any delayed work. As this is the final close it does not + * race with the set_ldisc code path. */ + clear_bit(TTY_LDISC, &tty->flags); clear_bit(TTY_DONT_FLIP, &tty->flags); cancel_delayed_work(&tty->flip.work); /* * Wait for ->hangup_work and ->flip.work handlers to terminate */ + flush_scheduled_work(); - + + /* + * Wait for any short term users (we know they are just driver + * side waiters as the file is closing so user count on the file + * side is zero. + */ + spin_lock_irqsave(&tty_ldisc_lock, flags); + while(tty->ldisc.refcount) + { + spin_unlock_irqrestore(&tty_ldisc_lock, flags); + wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); + spin_lock_irqsave(&tty_ldisc_lock, flags); + } + spin_unlock_irqrestore(&tty_ldisc_lock, flags); /* * Shutdown the current line discipline, and reset it to N_TTY. * N.B. why reset ldisc when we're releasing the memory?? + * + * FIXME: this MUST get fixed for the new reflocking */ if (tty->ldisc.close) (tty->ldisc.close)(tty); - module_put(tty->ldisc.owner); + tty_ldisc_put(tty->ldisc.num); - tty->ldisc = ldiscs[N_TTY]; - tty->termios->c_line = N_TTY; + /* + * Switch the line discipline back + */ + tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); + tty_set_termios_ldisc(tty,N_TTY); if (o_tty) { + /* FIXME: could o_tty be in setldisc here ? */ + clear_bit(TTY_LDISC, &o_tty->flags); if (o_tty->ldisc.close) (o_tty->ldisc.close)(o_tty); - module_put(o_tty->ldisc.owner); - o_tty->ldisc = ldiscs[N_TTY]; + tty_ldisc_put(o_tty->ldisc.num); + tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); + tty_set_termios_ldisc(o_tty,N_TTY); } - /* * The release_mem function takes care of the details of clearing * the slots and preserving the termios structure. @@ -1323,6 +1724,7 @@ static int tty_open(struct inode * inode, struct file * filp) unsigned short saved_flags = filp->f_flags; nonseekable_open(inode, filp); + retry_open: noctty = filp->f_flags & O_NOCTTY; index = -1; @@ -1358,53 +1760,13 @@ retry_open: return -ENODEV; } -#ifdef CONFIG_UNIX98_PTYS - if (device == MKDEV(TTYAUX_MAJOR,2)) { - int idr_ret; - - /* find a device that is not in use. */ - down(&allocated_ptys_lock); - if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { - up(&allocated_ptys_lock); - return -ENOMEM; - } - idr_ret = idr_get_new(&allocated_ptys, NULL, &index); - if (idr_ret < 0) { - up(&allocated_ptys_lock); - if (idr_ret == -EAGAIN) - return -ENOMEM; - return -EIO; - } - if (index >= pty_limit) { - idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); - return -EIO; - } - up(&allocated_ptys_lock); - - driver = ptm_driver; - retval = init_dev(driver, index, &tty); - if (retval) { - down(&allocated_ptys_lock); - idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); - return retval; - } - - set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ - if (devpts_pty_new(tty->link)) - retval = -ENOMEM; - } else -#endif - { - driver = get_tty_driver(device, &index); - if (!driver) - return -ENODEV; + driver = get_tty_driver(device, &index); + if (!driver) + return -ENODEV; got_driver: - retval = init_dev(driver, index, &tty); - if (retval) - return retval; - } + retval = init_dev(driver, index, &tty); + if (retval) + return retval; filp->private_data = tty; file_move(filp, &tty->tty_files); @@ -1431,15 +1793,6 @@ got_driver: printk(KERN_DEBUG "error %d in opening %s...", retval, tty->name); #endif - -#ifdef CONFIG_UNIX98_PTYS - if (index != -1) { - down(&allocated_ptys_lock); - idr_remove(&allocated_ptys, index); - up(&allocated_ptys_lock); - } -#endif - release_dev(filp); if (retval != -ERESTARTSYS) return retval; @@ -1467,6 +1820,62 @@ got_driver: return 0; } +#ifdef CONFIG_UNIX98_PTYS +static int ptmx_open(struct inode * inode, struct file * filp) +{ + struct tty_struct *tty; + int retval; + int index; + int idr_ret; + + nonseekable_open(inode, filp); + + /* find a device that is not in use. */ + down(&allocated_ptys_lock); + if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { + up(&allocated_ptys_lock); + return -ENOMEM; + } + idr_ret = idr_get_new(&allocated_ptys, NULL, &index); + if (idr_ret < 0) { + up(&allocated_ptys_lock); + if (idr_ret == -EAGAIN) + return -ENOMEM; + return -EIO; + } + if (index >= pty_limit) { + idr_remove(&allocated_ptys, index); + up(&allocated_ptys_lock); + return -EIO; + } + up(&allocated_ptys_lock); + + retval = init_dev(ptm_driver, index, &tty); + if (retval) + goto out; + + set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ + filp->private_data = tty; + file_move(filp, &tty->tty_files); + + retval = -ENOMEM; + if (devpts_pty_new(tty->link)) + goto out1; + + check_tty_count(tty, "tty_open"); + retval = ptm_driver->open(tty, filp); + if (!retval) + return 0; +out1: + release_dev(filp); +out: + down(&allocated_ptys_lock); + idr_remove(&allocated_ptys, index); + up(&allocated_ptys_lock); + return retval; +} +#endif + static int tty_release(struct inode * inode, struct file * filp) { lock_kernel(); @@ -1479,14 +1888,18 @@ static int tty_release(struct inode * inode, struct file * filp) static unsigned int tty_poll(struct file * filp, poll_table * wait) { struct tty_struct * tty; + struct tty_ldisc *ld; + int ret = 0; tty = (struct tty_struct *)filp->private_data; if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll")) return 0; - - if (tty->ldisc.poll) - return (tty->ldisc.poll)(tty, filp, wait); - return 0; + + ld = tty_ldisc_ref_wait(tty); + if (ld->poll) + ret = (ld->poll)(tty, filp, wait); + tty_ldisc_deref(ld); + return ret; } static int tty_fasync(int fd, struct file * filp, int on) @@ -1518,12 +1931,15 @@ static int tty_fasync(int fd, struct file * filp, int on) static int tiocsti(struct tty_struct *tty, char __user *p) { char ch, mbz = 0; - + struct tty_ldisc *ld; + if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ch, p)) return -EFAULT; - tty->ldisc.receive_buf(tty, &ch, &mbz, 1); + ld = tty_ldisc_ref_wait(tty); + ld->receive_buf(tty, &ch, &mbz, 1); + tty_ldisc_deref(ld); return 0; } @@ -1606,8 +2022,6 @@ static int fionbio(struct file *file, int __user *p) static int tiocsctty(struct tty_struct *tty, int arg) { - struct list_head *l; - struct pid *pid; task_t *p; if (current->signal->leader && @@ -1630,8 +2044,9 @@ static int tiocsctty(struct tty_struct *tty, int arg) */ read_lock(&tasklist_lock); - for_each_task_pid(tty->session, PIDTYPE_SID, p, l, pid) + do_each_task_pid(tty->session, PIDTYPE_SID, p) { p->signal->tty = NULL; + } while_each_task_pid(tty->session, PIDTYPE_SID, p); read_unlock(&tasklist_lock); } else return -EPERM; @@ -1647,13 +2062,16 @@ static int tiocsctty(struct tty_struct *tty, int arg) static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { + pid_t pgrp; /* * (tty == real_tty) is a cheap way of * testing if the tty is NOT a master pty. */ if (tty == real_tty && current->signal->tty != real_tty) return -ENOTTY; - return put_user(real_tty->pgrp, p); + + pgrp = vx_map_pid(real_tty->pgrp); + return put_user(pgrp, p); } static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) @@ -1671,6 +2089,8 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t return -ENOTTY; if (get_user(pgrp, p)) return -EFAULT; + + pgrp = vx_rmap_pid(pgrp); if (pgrp < 0) return -EINVAL; if (session_of_pgrp(pgrp) != current->signal->session) @@ -1772,6 +2192,7 @@ int tty_ioctl(struct inode * inode, struct file * file, struct tty_struct *tty, *real_tty; void __user *p = (void __user *)arg; int retval; + struct tty_ldisc *ld; tty = (struct tty_struct *)file->private_data; if (tty_paranoia_check(tty, inode, "tty_ioctl")) @@ -1861,6 +2282,7 @@ int tty_ioctl(struct inode * inode, struct file * file, case TIOCGSID: return tiocgsid(tty, real_tty, p); case TIOCGETD: + /* FIXME: check this is ok */ return put_user(tty->ldisc.num, (int __user *)p); case TIOCSETD: return tiocsetd(tty, p); @@ -1899,16 +2321,19 @@ int tty_ioctl(struct inode * inode, struct file * file, return tty_tiocmset(tty, file, cmd, p); } if (tty->driver->ioctl) { - int retval = (tty->driver->ioctl)(tty, file, cmd, arg); + retval = (tty->driver->ioctl)(tty, file, cmd, arg); if (retval != -ENOIOCTLCMD) return retval; } - if (tty->ldisc.ioctl) { - int retval = (tty->ldisc.ioctl)(tty, file, cmd, arg); - if (retval != -ENOIOCTLCMD) - return retval; + ld = tty_ldisc_ref_wait(tty); + retval = -EINVAL; + if (ld->ioctl) { + retval = ld->ioctl(tty, file, cmd, arg); + if (retval == -ENOIOCTLCMD) + retval = -EINVAL; } - return -EINVAL; + tty_ldisc_deref(ld); + return retval; } @@ -1938,21 +2363,26 @@ static void __do_SAK(void *arg) #else struct tty_struct *tty = arg; struct task_struct *p; - struct list_head *l; - struct pid *pid; int session; int i; struct file *filp; + struct tty_ldisc *disc; if (!tty) return; session = tty->session; - if (tty->ldisc.flush_buffer) - tty->ldisc.flush_buffer(tty); + + /* We don't want an ldisc switch during this */ + disc = tty_ldisc_ref(tty); + if (disc && disc->flush_buffer) + disc->flush_buffer(tty); + tty_ldisc_deref(disc); + if (tty->driver->flush_buffer) tty->driver->flush_buffer(tty); + read_lock(&tasklist_lock); - for_each_task_pid(session, PIDTYPE_SID, p, l, pid) { + do_each_task_pid(session, PIDTYPE_SID, p) { if (p->signal->tty == tty || session > 0) { printk(KERN_NOTICE "SAK: killed process %d" " (%s): p->signal->session==tty->session\n", @@ -1979,7 +2409,7 @@ static void __do_SAK(void *arg) spin_unlock(&p->files->file_lock); } task_unlock(p); - } + } while_each_task_pid(session, PIDTYPE_SID, p); read_unlock(&tasklist_lock); #endif } @@ -2002,24 +2432,29 @@ EXPORT_SYMBOL(do_SAK); /* * This routine is called out of the software interrupt to flush data - * from the flip buffer to the line discipline. + * from the flip buffer to the line discipline. */ + static void flush_to_ldisc(void *private_) { struct tty_struct *tty = (struct tty_struct *) private_; unsigned char *cp; char *fp; int count; - unsigned long flags; + unsigned long flags; + struct tty_ldisc *disc; + + disc = tty_ldisc_ref(tty); + if (disc == NULL) /* !TTY_LDISC */ + return; if (test_bit(TTY_DONT_FLIP, &tty->flags)) { /* * Do it after the next timer tick: */ schedule_delayed_work(&tty->flip.work, 1); - return; + goto out; } - spin_lock_irqsave(&tty->read_lock, flags); if (tty->flip.buf_num) { cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE; @@ -2038,7 +2473,31 @@ static void flush_to_ldisc(void *private_) tty->flip.count = 0; spin_unlock_irqrestore(&tty->read_lock, flags); - tty->ldisc.receive_buf(tty, cp, fp, count); + disc->receive_buf(tty, cp, fp, count); +out: + tty_ldisc_deref(disc); +} + +/* + * Call the ldisc flush directly from a driver. This function may + * return an error and need retrying by the user. + */ + +int tty_push_data(struct tty_struct *tty, unsigned char *cp, unsigned char *fp, int count) +{ + int ret = 0; + struct tty_ldisc *disc; + + disc = tty_ldisc_ref(tty); + if(test_bit(TTY_DONT_FLIP, &tty->flags)) + ret = -EAGAIN; + else if(disc == NULL) + ret = -EIO; + else + disc->receive_buf(tty, cp, fp, count); + tty_ldisc_deref(disc); + return ret; + } /* @@ -2060,9 +2519,20 @@ static int baud_table[] = { static int n_baud_table = ARRAY_SIZE(baud_table); +/** + * tty_termios_baud_rate + * @termios: termios structure + * + * Convert termios baud rate data into a speed. This should be called + * with the termios lock held if this termios is a terminal termios + * structure. May change the termios data. + */ + int tty_termios_baud_rate(struct termios *termios) { - unsigned int cbaud = termios->c_cflag & CBAUD; + unsigned int cbaud; + + cbaud = termios->c_cflag & CBAUD; if (cbaud & CBAUDEX) { cbaud &= ~CBAUDEX; @@ -2072,12 +2542,20 @@ int tty_termios_baud_rate(struct termios *termios) else cbaud += 15; } - return baud_table[cbaud]; } EXPORT_SYMBOL(tty_termios_baud_rate); +/** + * tty_get_baud_rate - get tty bit rates + * @tty: tty to query + * + * Returns the baud rate as an integer for this terminal. The + * termios lock must be held by the caller and the terminal bit + * flags may be updated. + */ + int tty_get_baud_rate(struct tty_struct *tty) { int baud = tty_termios_baud_rate(tty->termios); @@ -2096,6 +2574,17 @@ int tty_get_baud_rate(struct tty_struct *tty) EXPORT_SYMBOL(tty_get_baud_rate); +/** + * tty_flip_buffer_push - terminal + * @tty: tty to push + * + * Queue a push of the terminal flip buffers to the line discipline. This + * function must not be called from IRQ context if tty->low_latency is set. + * + * In the event of the queue being busy for flipping the work will be + * held off and retried later. + */ + void tty_flip_buffer_push(struct tty_struct *tty) { if (tty->low_latency) @@ -2113,12 +2602,13 @@ static void initialize_tty_struct(struct tty_struct *tty) { memset(tty, 0, sizeof(struct tty_struct)); tty->magic = TTY_MAGIC; - tty->ldisc = ldiscs[N_TTY]; + tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); tty->pgrp = -1; tty->flip.char_buf_ptr = tty->flip.char_buf; tty->flip.flag_buf_ptr = tty->flip.flag_buf; INIT_WORK(&tty->flip.work, flush_to_ldisc, tty); init_MUTEX(&tty->flip.pty_sem); + init_MUTEX(&tty->termios_sem); init_waitqueue_head(&tty->write_wait); init_waitqueue_head(&tty->read_wait); INIT_WORK(&tty->hangup_work, do_tty_hangup, tty); @@ -2154,6 +2644,7 @@ static struct class_simple *tty_class; void tty_register_device(struct tty_driver *driver, unsigned index, struct device *device) { + char name[64]; dev_t dev = MKDEV(driver->major, driver->minor_start) + index; if (index >= driver->num) { @@ -2165,13 +2656,11 @@ void tty_register_device(struct tty_driver *driver, unsigned index, devfs_mk_cdev(dev, S_IFCHR | S_IRUSR | S_IWUSR, "%s%d", driver->devfs_name, index + driver->name_base); - /* we don't care about the ptys */ - /* how nice to hide this behind some crappy interface.. */ - if (driver->type != TTY_DRIVER_TYPE_PTY) { - char name[64]; + if (driver->type == TTY_DRIVER_TYPE_PTY) + pty_line_name(driver, index, name); + else tty_line_name(driver, index, name); - class_simple_device_add(tty_class, dev, device, name); - } + class_simple_device_add(tty_class, dev, device, name); } /** @@ -2441,7 +2930,7 @@ static int __init tty_init(void) class_simple_device_add(tty_class, MKDEV(TTYAUX_MAJOR, 1), NULL, "console"); #ifdef CONFIG_UNIX98_PTYS - cdev_init(&ptmx_cdev, &tty_fops); + cdev_init(&ptmx_cdev, &ptmx_fops); if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) panic("Couldn't register /dev/ptmx driver\n");