vserver 2.0 rc7
[linux-2.6.git] / arch / um / drivers / line.c
index d4286de..025d3be 100644 (file)
@@ -39,19 +39,69 @@ static void line_timer_cb(void *arg)
        line_interrupt(line->driver->read_irq, arg, NULL);
 }
 
-static int write_room(struct line *dev)
+/* Returns the free space inside the ring buffer of this line.
+ *
+ * Should be called while holding line->lock (this does not modify datas).
+ */
+static int write_room(struct line *line)
 {
        int n;
 
-       if (dev->buffer == NULL)
-               return (LINE_BUFSIZE - 1);
+       if (line->buffer == NULL)
+               return LINE_BUFSIZE - 1;
+
+       /* This is for the case where the buffer is wrapped! */
+       n = line->head - line->tail;
 
-       n = dev->head - dev->tail;
        if (n <= 0)
-               n = LINE_BUFSIZE + n;
-       return (n - 1);
+               n = LINE_BUFSIZE + n; /* The other case */
+       return n - 1;
+}
+
+int line_write_room(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int room;
+
+       if (tty->stopped)
+               return 0;
+
+       spin_lock_irqsave(&line->lock, flags);
+       room = write_room(line);
+       spin_unlock_irqrestore(&line->lock, flags);
+
+       /*XXX: Warning to remove */
+       if (0 == room)
+               printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
+                      __FUNCTION__,tty->name);
+       return room;
+}
+
+int line_chars_in_buffer(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&line->lock, flags);
+
+       /*write_room subtracts 1 for the needed NULL, so we readd it.*/
+       ret = LINE_BUFSIZE - (write_room(line) + 1);
+       spin_unlock_irqrestore(&line->lock, flags);
+
+       return ret;
 }
 
+/*
+ * This copies the content of buf into the circular buffer associated with
+ * this line.
+ * The return value is the number of characters actually copied, i.e. the ones
+ * for which there was space: this function is not supposed to ever flush out
+ * the circular buffer.
+ *
+ * Must be called while holding line->lock!
+ */
 static int buffer_data(struct line *line, const char *buf, int len)
 {
        int end, room;
@@ -70,48 +120,95 @@ static int buffer_data(struct line *line, const char *buf, int len)
        len = (len > room) ? room : len;
 
        end = line->buffer + LINE_BUFSIZE - line->tail;
-       if(len < end){
+
+       if (len < end){
                memcpy(line->tail, buf, len);
                line->tail += len;
-       }
-       else {
+       } else {
+               /* The circular buffer is wrapping */
                memcpy(line->tail, buf, end);
                buf += end;
                memcpy(line->buffer, buf, len - end);
                line->tail = line->buffer + len - end;
        }
 
-       return(len);
+       return len;
 }
 
+/*
+ * Flushes the ring buffer to the output channels. That is, write_chan is
+ * called, passing it line->head as buffer, and an appropriate count.
+ *
+ * On exit, returns 1 when the buffer is empty,
+ * 0 when the buffer is not empty on exit,
+ * and -errno when an error occurred.
+ *
+ * Must be called while holding line->lock!*/
 static int flush_buffer(struct line *line)
 {
        int n, count;
 
        if ((line->buffer == NULL) || (line->head == line->tail))
-               return(1);
+               return 1;
 
        if (line->tail < line->head) {
+               /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
                count = line->buffer + LINE_BUFSIZE - line->head;
+
                n = write_chan(&line->chan_list, line->head, count,
                               line->driver->write_irq);
                if (n < 0)
-                       return(n);
-               if (n == count)
+                       return n;
+               if (n == count) {
+                       /* We have flushed from ->head to buffer end, now we
+                        * must flush only from the beginning to ->tail.*/
                        line->head = line->buffer;
-               else {
+               else {
                        line->head += n;
-                       return(0);
+                       return 0;
                }
        }
 
        count = line->tail - line->head;
        n = write_chan(&line->chan_list, line->head, count, 
                       line->driver->write_irq);
-       if(n < 0) return(n);
+
+       if(n < 0)
+               return n;
 
        line->head += n;
-       return(line->head == line->tail);
+       return line->head == line->tail;
+}
+
+void line_flush_buffer(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int err;
+
+       /*XXX: copied from line_write, verify if it is correct!*/
+       if(tty->stopped)
+               return;
+               //return 0;
+
+       spin_lock_irqsave(&line->lock, flags);
+       err = flush_buffer(line);
+       /*if (err == 1)
+               err = 0;*/
+       spin_unlock_irqrestore(&line->lock, flags);
+       //return err;
+}
+
+/* We map both ->flush_chars and ->put_char (which go in pair) onto ->flush_buffer
+ * and ->write. Hope it's not that bad.*/
+void line_flush_chars(struct tty_struct *tty)
+{
+       line_flush_buffer(tty);
+}
+
+void line_put_char(struct tty_struct *tty, unsigned char ch)
+{
+       line_write(tty, &ch, sizeof(ch));
 }
 
 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
@@ -120,38 +217,31 @@ int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
        unsigned long flags;
        int n, err, ret = 0;
 
-       if(tty->stopped) return 0;
+       if(tty->stopped)
+               return 0;
 
-       down(&line->sem);
-       if(line->head != line->tail){
-               local_irq_save(flags);
+       spin_lock_irqsave(&line->lock, flags);
+       if (line->head != line->tail) {
                ret = buffer_data(line, buf, len);
                err = flush_buffer(line);
-               local_irq_restore(flags);
-               if(err <= 0)
+               if (err <= 0 && (err != -EAGAIN || !ret))
                        ret = err;
-       }
-       else {
+       } else {
                n = write_chan(&line->chan_list, buf, len, 
                               line->driver->write_irq);
-               if(n < 0){
+               if (n < 0) {
                        ret = n;
                        goto out_up;
                }
 
                len -= n;
                ret += n;
-               if(len > 0)
+               if (len > 0)
                        ret += buffer_data(line, buf + n, len);
        }
- out_up:
-       up(&line->sem);
-       return(ret);
-}
-
-void line_put_char(struct tty_struct *tty, unsigned char ch)
-{
-       line_write(tty, &ch, sizeof(ch));
+out_up:
+       spin_unlock_irqrestore(&line->lock, flags);
+       return ret;
 }
 
 void line_set_termios(struct tty_struct *tty, struct termios * old)
@@ -159,11 +249,6 @@ void line_set_termios(struct tty_struct *tty, struct termios * old)
        /* nothing */
 }
 
-int line_chars_in_buffer(struct tty_struct *tty)
-{
-       return 0;
-}
-
 static struct {
        int  cmd;
        char *level;
@@ -250,7 +335,7 @@ int line_ioctl(struct tty_struct *tty, struct file * file,
                ret = -ENOIOCTLCMD;
                break;
        }
-       return(ret);
+       return ret;
 }
 
 static irqreturn_t line_write_interrupt(int irq, void *data,
@@ -260,18 +345,23 @@ static irqreturn_t line_write_interrupt(int irq, void *data,
        struct line *line = tty->driver_data;
        int err;
 
+       /* Interrupts are enabled here because we registered the interrupt with
+        * SA_INTERRUPT (see line_setup_irq).*/
+
+       spin_lock_irq(&line->lock);
        err = flush_buffer(line);
-       if(err == 0)
-               return(IRQ_NONE);
-       else if(err < 0){
+       if (err == 0) {
+               return IRQ_NONE;
+       } else if(err < 0) {
                line->head = line->buffer;
                line->tail = line->buffer;
        }
+       spin_unlock_irq(&line->lock);
 
        if(tty == NULL)
-               return(IRQ_NONE);
+               return IRQ_NONE;
 
-       if(test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
+       if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
           (tty->ldisc.write_wakeup != NULL))
                (tty->ldisc.write_wakeup)(tty);
        
@@ -281,9 +371,9 @@ static irqreturn_t line_write_interrupt(int irq, void *data,
         * writes.
         */
 
-       if(waitqueue_active(&tty->write_wait))
+       if (waitqueue_active(&tty->write_wait))
                wake_up_interruptible(&tty->write_wait);
-       return(IRQ_HANDLED);
+       return IRQ_HANDLED;
 }
 
 int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
@@ -292,15 +382,18 @@ int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
        struct line_driver *driver = line->driver;
        int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
 
-       if(input) err = um_request_irq(driver->read_irq, fd, IRQ_READ, 
+       if (input)
+               err = um_request_irq(driver->read_irq, fd, IRQ_READ,
                                       line_interrupt, flags, 
                                       driver->read_irq_name, tty);
-       if(err) return(err);
-       if(output) err = um_request_irq(driver->write_irq, fd, IRQ_WRITE, 
+       if (err)
+               return err;
+       if (output)
+               err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
                                        line_write_interrupt, flags, 
                                        driver->write_irq_name, tty);
        line->have_irq = 1;
-       return(err);
+       return err;
 }
 
 void line_disable(struct tty_struct *tty, int current_irq)
@@ -336,7 +429,9 @@ int line_open(struct line *lines, struct tty_struct *tty,
        line = &lines[tty->index];
        tty->driver_data = line;
 
-       down(&line->sem);
+       /* The IRQ which takes this lock is not yet enabled and won't be run
+        * before the end, so we don't need to use spin_lock_irq.*/
+       spin_lock(&line->lock);
        if (tty->count == 1) {
                if (!line->valid) {
                        err = -ENODEV;
@@ -349,6 +444,7 @@ int line_open(struct line *lines, struct tty_struct *tty,
                        err = open_chan(&line->chan_list);
                        if(err) goto out;
                }
+               /* Here the interrupt is registered.*/
                enable_chan(&line->chan_list, tty);
                INIT_WORK(&line->task, line_timer_cb, tty);
        }
@@ -362,21 +458,36 @@ int line_open(struct line *lines, struct tty_struct *tty,
        line->count++;
 
 out:
-       up(&line->sem);
-       return(err);
+       spin_unlock(&line->lock);
+       return err;
 }
 
+static void unregister_winch(struct tty_struct *tty);
+
 void line_close(struct tty_struct *tty, struct file * filp)
 {
        struct line *line = tty->driver_data;
 
-       down(&line->sem);
+       /* XXX: I assume this should be called in process context, not with
+         *  interrupts disabled!
+         */
+       spin_lock_irq(&line->lock);
+
+       /* We ignore the error anyway! */
+       flush_buffer(line);
+
        line->count--;
        if (tty->count == 1) {
                line_disable(tty, -1);
                tty->driver_data = NULL;
        }
-       up(&line->sem);
+
+        if((line->count == 0) && line->sigio){
+                unregister_winch(tty);
+                line->sigio = 0;
+        }
+
+       spin_unlock_irq(&line->lock);
 }
 
 void close_lines(struct line *lines, int nlines)
@@ -387,31 +498,41 @@ void close_lines(struct line *lines, int nlines)
                close_chan(&lines[i].chan_list);
 }
 
-int line_setup(struct line *lines, int num, char *init, int all_allowed)
+/* Common setup code for both startup command line and mconsole initialization.
+ * @lines contains the the array (of size @num) to modify;
+ * @init is the setup string;
+ * @all_allowed is a boolean saying if we can setup the whole @lines
+ * at once. For instance, it will be usually true for startup init. (where we
+ * can use con=xterm) and false for mconsole.*/
+
+int line_setup(struct line *lines, unsigned int num, char *init, int all_allowed)
 {
        int i, n;
        char *end;
 
-       if(*init == '=') n = -1;
-       else {
+       if(*init == '=') {
+               /* We said con=/ssl= instead of con#=, so we are configuring all
+                * consoles at once.*/
+               n = -1;
+       } else {
                n = simple_strtoul(init, &end, 0);
                if(*end != '='){
                        printk(KERN_ERR "line_setup failed to parse \"%s\"\n", 
                               init);
-                       return(0);
+                       return 0;
                }
                init = end;
        }
        init++;
-       if((n >= 0) && (n >= num)){
+
+       if (n >= (signed int) num) {
                printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
                       n, num - 1);
-               return(0);
-       }
-       else if (n >= 0){
+               return 0;
+       } else if (n >= 0){
                if (lines[n].count > 0) {
                        printk("line_setup - device %d is open\n", n);
-                       return(0);
+                       return 0;
                }
                if (lines[n].init_pri <= INIT_ONE){
                        lines[n].init_pri = INIT_ONE;
@@ -422,13 +543,11 @@ int line_setup(struct line *lines, int num, char *init, int all_allowed)
                                lines[n].valid = 1;
                        }       
                }
-       }
-       else if(!all_allowed){
+       } else if(!all_allowed){
                printk("line_setup - can't configure all devices from "
                       "mconsole\n");
-               return(0);
-       }
-       else {
+               return 0;
+       } else {
                for(i = 0; i < num; i++){
                        if(lines[i].init_pri <= INIT_ALL){
                                lines[i].init_pri = INIT_ALL;
@@ -440,21 +559,21 @@ int line_setup(struct line *lines, int num, char *init, int all_allowed)
                        }
                }
        }
-       return(1);
+       return 1;
 }
 
-int line_config(struct line *lines, int num, char *str)
+int line_config(struct line *lines, unsigned int num, char *str)
 {
        char *new = uml_strdup(str);
 
        if(new == NULL){
                printk("line_config - uml_strdup failed\n");
-               return(-ENOMEM);
+               return -ENOMEM;
        }
-       return(!line_setup(lines, num, new, 0));
+       return !line_setup(lines, num, new, 0);
 }
 
-int line_get_config(char *name, struct line *lines, int num, char *str, 
+int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
                    int size, char **error_out)
 {
        struct line *line;
@@ -464,47 +583,33 @@ int line_get_config(char *name, struct line *lines, int num, char *str,
        dev = simple_strtoul(name, &end, 0);
        if((*end != '\0') || (end == name)){
                *error_out = "line_get_config failed to parse device number";
-               return(0);
+               return 0;
        }
 
        if((dev < 0) || (dev >= num)){
-               *error_out = "device number of of range";
-               return(0);
+               *error_out = "device number out of range";
+               return 0;
        }
 
        line = &lines[dev];
 
-       down(&line->sem);
+       spin_lock(&line->lock);
        if(!line->valid)
                CONFIG_CHUNK(str, size, n, "none", 1);
        else if(line->count == 0)
                CONFIG_CHUNK(str, size, n, line->init_str, 1);
        else n = chan_config_string(&line->chan_list, str, size, error_out);
-       up(&line->sem);
+       spin_unlock(&line->lock);
 
-       return(n);
+       return n;
 }
 
-int line_remove(struct line *lines, int num, char *str)
+int line_remove(struct line *lines, unsigned int num, char *str)
 {
        char config[sizeof("conxxxx=none\0")];
 
        sprintf(config, "%s=none", str);
-       return(!line_setup(lines, num, config, 0));
-}
-
-int line_write_room(struct tty_struct *tty)
-{
-       struct line *dev = tty->driver_data;
-       int room;
-
-       if (tty->stopped)
-               return 0;
-       room = write_room(dev);
-       if (0 == room)
-               printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
-                      __FUNCTION__,tty->name);
-       return room;
+       return !line_setup(lines, num, config, 0);
 }
 
 struct tty_driver *line_register_devfs(struct lines *set,
@@ -553,7 +658,7 @@ void lines_init(struct line *lines, int nlines)
        for(i = 0; i < nlines; i++){
                line = &lines[i];
                INIT_LIST_HEAD(&line->chan_list);
-               sema_init(&line->sem, 1);
+               spin_lock_init(&line->lock);
                if(line->init_str != NULL){
                        line->init_str = uml_strdup(line->init_str);
                        if(line->init_str == NULL)
@@ -587,7 +692,7 @@ irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
                                       "errno = %d\n", -err);
                                printk("fd %d is losing SIGWINCH support\n",
                                       winch->tty_fd);
-                               return(IRQ_HANDLED);
+                               return IRQ_HANDLED;
                        }
                        goto out;
                }
@@ -603,7 +708,7 @@ irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
  out:
        if(winch->fd != -1)
                reactivate_fd(winch->fd, WINCH_IRQ);
-       return(IRQ_HANDLED);
+       return IRQ_HANDLED;
 }
 
 DECLARE_MUTEX(winch_handler_sem);
@@ -625,7 +730,7 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
                                   .pid         = pid,
                                   .tty         = tty });
        list_add(&winch->list, &winch_handlers);
-       if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt, 
+       if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
                          SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, 
                          "winch", winch) < 0)
                printk("register_winch_irq - failed to register IRQ\n");
@@ -633,6 +738,34 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
        up(&winch_handler_sem);
 }
 
+static void unregister_winch(struct tty_struct *tty)
+{
+       struct list_head *ele;
+       struct winch *winch, *found = NULL;
+
+       down(&winch_handler_sem);
+       list_for_each(ele, &winch_handlers){
+               winch = list_entry(ele, struct winch, list);
+                if(winch->tty == tty){
+                        found = winch;
+                        break;
+                }
+        }
+
+        if(found == NULL)
+                goto out;
+
+        if(winch->pid != -1)
+                os_kill_process(winch->pid, 1);
+
+        free_irq_by_irq_and_dev(WINCH_IRQ, winch);
+        free_irq(WINCH_IRQ, winch);
+        list_del(&winch->list);
+        kfree(winch);
+ out:
+       up(&winch_handler_sem);
+}
+
 static void winch_cleanup(void)
 {
        struct list_head *ele;
@@ -656,26 +789,16 @@ char *add_xterm_umid(char *base)
        int len;
 
        umid = get_umid(1);
-       if(umid == NULL) return(base);
+       if(umid == NULL)
+               return base;
        
        len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
        title = kmalloc(len, GFP_KERNEL);
        if(title == NULL){
                printk("Failed to allocate buffer for xterm title\n");
-               return(base);
+               return base;
        }
 
        snprintf(title, len, "%s (%s)", base, umid);
-       return(title);
+       return title;
 }
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */