From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/um/drivers/line.c | 768 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 768 insertions(+)
 create mode 100644 arch/um/drivers/line.c

(limited to 'arch/um/drivers/line.c')

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
new file mode 100644
index 000000000..62087028a
--- /dev/null
+++ b/arch/um/drivers/line.c
@@ -0,0 +1,768 @@
+/*
+ * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/irqreturn.h>
+#include <linux/kd.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "chan.h"
+#include <irq_kern.h>
+#include <irq_user.h>
+#include <kern_util.h>
+#include <os.h>
+
+#define LINE_BUFSIZE 4096
+
+static irqreturn_t line_interrupt(int irq, void *data)
+{
+	struct chan *chan = data;
+	struct line *line = chan->line;
+
+	if (line)
+		chan_interrupt(line, irq);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Returns the free space inside the ring buffer of this line.
+ *
+ * Should be called while holding line->lock (this does not modify data).
+ */
+static int write_room(struct line *line)
+{
+	int n;
+
+	if (line->buffer == NULL)
+		return LINE_BUFSIZE - 1;
+
+	/* This is for the case where the buffer is wrapped! */
+	n = line->head - line->tail;
+
+	if (n <= 0)
+		n += LINE_BUFSIZE; /* 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;
+
+	spin_lock_irqsave(&line->lock, flags);
+	room = write_room(line);
+	spin_unlock_irqrestore(&line->lock, flags);
+
+	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;
+
+	if (line->buffer == NULL) {
+		line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
+		if (line->buffer == NULL) {
+			printk(KERN_ERR "buffer_data - atomic allocation "
+			       "failed\n");
+			return 0;
+		}
+		line->head = line->buffer;
+		line->tail = line->buffer;
+	}
+
+	room = write_room(line);
+	len = (len > room) ? room : len;
+
+	end = line->buffer + LINE_BUFSIZE - line->tail;
+
+	if (len < end) {
+		memcpy(line->tail, buf, len);
+		line->tail += len;
+	}
+	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;
+}
+
+/*
+ * 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;
+
+	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_out, line->head, count,
+			       line->driver->write_irq);
+		if (n < 0)
+			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 {
+			line->head += n;
+			return 0;
+		}
+	}
+
+	count = line->tail - line->head;
+	n = write_chan(line->chan_out, line->head, count,
+		       line->driver->write_irq);
+
+	if (n < 0)
+		return n;
+
+	line->head += n;
+	return line->head == line->tail;
+}
+
+void line_flush_buffer(struct tty_struct *tty)
+{
+	struct line *line = tty->driver_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&line->lock, flags);
+	flush_buffer(line);
+	spin_unlock_irqrestore(&line->lock, flags);
+}
+
+/*
+ * 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);
+}
+
+int line_put_char(struct tty_struct *tty, unsigned char ch)
+{
+	return line_write(tty, &ch, sizeof(ch));
+}
+
+int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
+{
+	struct line *line = tty->driver_data;
+	unsigned long flags;
+	int n, ret = 0;
+
+	spin_lock_irqsave(&line->lock, flags);
+	if (line->head != line->tail)
+		ret = buffer_data(line, buf, len);
+	else {
+		n = write_chan(line->chan_out, buf, len,
+			       line->driver->write_irq);
+		if (n < 0) {
+			ret = n;
+			goto out_up;
+		}
+
+		len -= n;
+		ret += n;
+		if (len > 0)
+			ret += buffer_data(line, buf + n, len);
+	}
+out_up:
+	spin_unlock_irqrestore(&line->lock, flags);
+	return ret;
+}
+
+void line_set_termios(struct tty_struct *tty, struct ktermios * old)
+{
+	/* nothing */
+}
+
+void line_throttle(struct tty_struct *tty)
+{
+	struct line *line = tty->driver_data;
+
+	deactivate_chan(line->chan_in, line->driver->read_irq);
+	line->throttled = 1;
+}
+
+void line_unthrottle(struct tty_struct *tty)
+{
+	struct line *line = tty->driver_data;
+
+	line->throttled = 0;
+	chan_interrupt(line, line->driver->read_irq);
+
+	/*
+	 * Maybe there is enough stuff pending that calling the interrupt
+	 * throttles us again.  In this case, line->throttled will be 1
+	 * again and we shouldn't turn the interrupt back on.
+	 */
+	if (!line->throttled)
+		reactivate_chan(line->chan_in, line->driver->read_irq);
+}
+
+static irqreturn_t line_write_interrupt(int irq, void *data)
+{
+	struct chan *chan = data;
+	struct line *line = chan->line;
+	int err;
+
+	/*
+	 * Interrupts are disabled here because genirq keep irqs disabled when
+	 * calling the action handler.
+	 */
+
+	spin_lock(&line->lock);
+	err = flush_buffer(line);
+	if (err == 0) {
+		spin_unlock(&line->lock);
+		return IRQ_NONE;
+	} else if (err < 0) {
+		line->head = line->buffer;
+		line->tail = line->buffer;
+	}
+	spin_unlock(&line->lock);
+
+	tty_port_tty_wakeup(&line->port);
+
+	return IRQ_HANDLED;
+}
+
+int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
+{
+	const struct line_driver *driver = line->driver;
+	int err = 0;
+
+	if (input)
+		err = um_request_irq(driver->read_irq, fd, IRQ_READ,
+				     line_interrupt, IRQF_SHARED,
+				     driver->read_irq_name, data);
+	if (err)
+		return err;
+	if (output)
+		err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
+				     line_write_interrupt, IRQF_SHARED,
+				     driver->write_irq_name, data);
+	return err;
+}
+
+static int line_activate(struct tty_port *port, struct tty_struct *tty)
+{
+	int ret;
+	struct line *line = tty->driver_data;
+
+	ret = enable_chan(line);
+	if (ret)
+		return ret;
+
+	if (!line->sigio) {
+		chan_enable_winch(line->chan_out, port);
+		line->sigio = 1;
+	}
+
+	chan_window_size(line, &tty->winsize.ws_row,
+		&tty->winsize.ws_col);
+
+	return 0;
+}
+
+static void unregister_winch(struct tty_struct *tty);
+
+static void line_destruct(struct tty_port *port)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+	struct line *line = tty->driver_data;
+
+	if (line->sigio) {
+		unregister_winch(tty);
+		line->sigio = 0;
+	}
+}
+
+static const struct tty_port_operations line_port_ops = {
+	.activate = line_activate,
+	.destruct = line_destruct,
+};
+
+int line_open(struct tty_struct *tty, struct file *filp)
+{
+	struct line *line = tty->driver_data;
+
+	return tty_port_open(&line->port, tty, filp);
+}
+
+int line_install(struct tty_driver *driver, struct tty_struct *tty,
+		 struct line *line)
+{
+	int ret;
+
+	ret = tty_standard_install(driver, tty);
+	if (ret)
+		return ret;
+
+	tty->driver_data = line;
+
+	return 0;
+}
+
+void line_close(struct tty_struct *tty, struct file * filp)
+{
+	struct line *line = tty->driver_data;
+
+	tty_port_close(&line->port, tty, filp);
+}
+
+void line_hangup(struct tty_struct *tty)
+{
+	struct line *line = tty->driver_data;
+
+	tty_port_hangup(&line->port);
+}
+
+void close_lines(struct line *lines, int nlines)
+{
+	int i;
+
+	for(i = 0; i < nlines; i++)
+		close_chan(&lines[i]);
+}
+
+int setup_one_line(struct line *lines, int n, char *init,
+		   const struct chan_opts *opts, char **error_out)
+{
+	struct line *line = &lines[n];
+	struct tty_driver *driver = line->driver->driver;
+	int err = -EINVAL;
+
+	if (line->port.count) {
+		*error_out = "Device is already open";
+		goto out;
+	}
+
+	if (!strcmp(init, "none")) {
+		if (line->valid) {
+			line->valid = 0;
+			kfree(line->init_str);
+			tty_unregister_device(driver, n);
+			parse_chan_pair(NULL, line, n, opts, error_out);
+			err = 0;
+		}
+	} else {
+		char *new = kstrdup(init, GFP_KERNEL);
+		if (!new) {
+			*error_out = "Failed to allocate memory";
+			return -ENOMEM;
+		}
+		if (line->valid) {
+			tty_unregister_device(driver, n);
+			kfree(line->init_str);
+		}
+		line->init_str = new;
+		line->valid = 1;
+		err = parse_chan_pair(new, line, n, opts, error_out);
+		if (!err) {
+			struct device *d = tty_port_register_device(&line->port,
+					driver, n, NULL);
+			if (IS_ERR(d)) {
+				*error_out = "Failed to register device";
+				err = PTR_ERR(d);
+				parse_chan_pair(NULL, line, n, opts, error_out);
+			}
+		}
+		if (err) {
+			line->init_str = NULL;
+			line->valid = 0;
+			kfree(new);
+		}
+	}
+out:
+	return err;
+}
+
+/*
+ * Common setup code for both startup command line and mconsole initialization.
+ * @lines contains the array (of size @num) to modify;
+ * @init is the setup string;
+ * @error_out is an error string in the case of failure;
+ */
+
+int line_setup(char **conf, unsigned int num, char **def,
+	       char *init, char *name)
+{
+	char *error;
+
+	if (*init == '=') {
+		/*
+		 * We said con=/ssl= instead of con#=, so we are configuring all
+		 * consoles at once.
+		 */
+		*def = init + 1;
+	} else {
+		char *end;
+		unsigned n = simple_strtoul(init, &end, 0);
+
+		if (*end != '=') {
+			error = "Couldn't parse device number";
+			goto out;
+		}
+		if (n >= num) {
+			error = "Device number out of range";
+			goto out;
+		}
+		conf[n] = end + 1;
+	}
+	return 0;
+
+out:
+	printk(KERN_ERR "Failed to set up %s with "
+	       "configuration string \"%s\" : %s\n", name, init, error);
+	return -EINVAL;
+}
+
+int line_config(struct line *lines, unsigned int num, char *str,
+		const struct chan_opts *opts, char **error_out)
+{
+	char *end;
+	int n;
+
+	if (*str == '=') {
+		*error_out = "Can't configure all devices from mconsole";
+		return -EINVAL;
+	}
+
+	n = simple_strtoul(str, &end, 0);
+	if (*end++ != '=') {
+		*error_out = "Couldn't parse device number";
+		return -EINVAL;
+	}
+	if (n >= num) {
+		*error_out = "Device number out of range";
+		return -EINVAL;
+	}
+
+	return setup_one_line(lines, n, end, opts, error_out);
+}
+
+int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
+		    int size, char **error_out)
+{
+	struct line *line;
+	char *end;
+	int dev, n = 0;
+
+	dev = simple_strtoul(name, &end, 0);
+	if ((*end != '\0') || (end == name)) {
+		*error_out = "line_get_config failed to parse device number";
+		return 0;
+	}
+
+	if ((dev < 0) || (dev >= num)) {
+		*error_out = "device number out of range";
+		return 0;
+	}
+
+	line = &lines[dev];
+
+	if (!line->valid)
+		CONFIG_CHUNK(str, size, n, "none", 1);
+	else {
+		struct tty_struct *tty = tty_port_tty_get(&line->port);
+		if (tty == NULL) {
+			CONFIG_CHUNK(str, size, n, line->init_str, 1);
+		} else {
+			n = chan_config_string(line, str, size, error_out);
+			tty_kref_put(tty);
+		}
+	}
+
+	return n;
+}
+
+int line_id(char **str, int *start_out, int *end_out)
+{
+	char *end;
+	int n;
+
+	n = simple_strtoul(*str, &end, 0);
+	if ((*end != '\0') || (end == *str))
+		return -1;
+
+	*str = end;
+	*start_out = n;
+	*end_out = n;
+	return n;
+}
+
+int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
+{
+	if (n >= num) {
+		*error_out = "Device number out of range";
+		return -EINVAL;
+	}
+	return setup_one_line(lines, n, "none", NULL, error_out);
+}
+
+int register_lines(struct line_driver *line_driver,
+		   const struct tty_operations *ops,
+		   struct line *lines, int nlines)
+{
+	struct tty_driver *driver = alloc_tty_driver(nlines);
+	int err;
+	int i;
+
+	if (!driver)
+		return -ENOMEM;
+
+	driver->driver_name = line_driver->name;
+	driver->name = line_driver->device_name;
+	driver->major = line_driver->major;
+	driver->minor_start = line_driver->minor_start;
+	driver->type = line_driver->type;
+	driver->subtype = line_driver->subtype;
+	driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
+	driver->init_termios = tty_std_termios;
+	
+	for (i = 0; i < nlines; i++) {
+		tty_port_init(&lines[i].port);
+		lines[i].port.ops = &line_port_ops;
+		spin_lock_init(&lines[i].lock);
+		lines[i].driver = line_driver;
+		INIT_LIST_HEAD(&lines[i].chan_list);
+	}
+	tty_set_operations(driver, ops);
+
+	err = tty_register_driver(driver);
+	if (err) {
+		printk(KERN_ERR "register_lines : can't register %s driver\n",
+		       line_driver->name);
+		put_tty_driver(driver);
+		for (i = 0; i < nlines; i++)
+			tty_port_destroy(&lines[i].port);
+		return err;
+	}
+
+	line_driver->driver = driver;
+	mconsole_register_dev(&line_driver->mc);
+	return 0;
+}
+
+static DEFINE_SPINLOCK(winch_handler_lock);
+static LIST_HEAD(winch_handlers);
+
+struct winch {
+	struct list_head list;
+	int fd;
+	int tty_fd;
+	int pid;
+	struct tty_port *port;
+	unsigned long stack;
+	struct work_struct work;
+};
+
+static void __free_winch(struct work_struct *work)
+{
+	struct winch *winch = container_of(work, struct winch, work);
+	um_free_irq(WINCH_IRQ, winch);
+
+	if (winch->pid != -1)
+		os_kill_process(winch->pid, 1);
+	if (winch->stack != 0)
+		free_stack(winch->stack, 0);
+	kfree(winch);
+}
+
+static void free_winch(struct winch *winch)
+{
+	int fd = winch->fd;
+	winch->fd = -1;
+	if (fd != -1)
+		os_close_file(fd);
+	list_del(&winch->list);
+	__free_winch(&winch->work);
+}
+
+static irqreturn_t winch_interrupt(int irq, void *data)
+{
+	struct winch *winch = data;
+	struct tty_struct *tty;
+	struct line *line;
+	int fd = winch->fd;
+	int err;
+	char c;
+	struct pid *pgrp;
+
+	if (fd != -1) {
+		err = generic_read(fd, &c, NULL);
+		if (err < 0) {
+			if (err != -EAGAIN) {
+				winch->fd = -1;
+				list_del(&winch->list);
+				os_close_file(fd);
+				printk(KERN_ERR "winch_interrupt : "
+				       "read failed, errno = %d\n", -err);
+				printk(KERN_ERR "fd %d is losing SIGWINCH "
+				       "support\n", winch->tty_fd);
+				INIT_WORK(&winch->work, __free_winch);
+				schedule_work(&winch->work);
+				return IRQ_HANDLED;
+			}
+			goto out;
+		}
+	}
+	tty = tty_port_tty_get(winch->port);
+	if (tty != NULL) {
+		line = tty->driver_data;
+		if (line != NULL) {
+			chan_window_size(line, &tty->winsize.ws_row,
+					 &tty->winsize.ws_col);
+			pgrp = tty_get_pgrp(tty);
+			if (pgrp)
+				kill_pgrp(pgrp, SIGWINCH, 1);
+			put_pid(pgrp);
+		}
+		tty_kref_put(tty);
+	}
+ out:
+	if (winch->fd != -1)
+		reactivate_fd(winch->fd, WINCH_IRQ);
+	return IRQ_HANDLED;
+}
+
+void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
+			unsigned long stack)
+{
+	struct winch *winch;
+
+	winch = kmalloc(sizeof(*winch), GFP_KERNEL);
+	if (winch == NULL) {
+		printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
+		goto cleanup;
+	}
+
+	*winch = ((struct winch) { .list  	= LIST_HEAD_INIT(winch->list),
+				   .fd  	= fd,
+				   .tty_fd 	= tty_fd,
+				   .pid  	= pid,
+				   .port 	= port,
+				   .stack	= stack });
+
+	if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
+			   IRQF_SHARED, "winch", winch) < 0) {
+		printk(KERN_ERR "register_winch_irq - failed to register "
+		       "IRQ\n");
+		goto out_free;
+	}
+
+	spin_lock(&winch_handler_lock);
+	list_add(&winch->list, &winch_handlers);
+	spin_unlock(&winch_handler_lock);
+
+	return;
+
+ out_free:
+	kfree(winch);
+ cleanup:
+	os_kill_process(pid, 1);
+	os_close_file(fd);
+	if (stack != 0)
+		free_stack(stack, 0);
+}
+
+static void unregister_winch(struct tty_struct *tty)
+{
+	struct list_head *ele, *next;
+	struct winch *winch;
+	struct tty_struct *wtty;
+
+	spin_lock(&winch_handler_lock);
+
+	list_for_each_safe(ele, next, &winch_handlers) {
+		winch = list_entry(ele, struct winch, list);
+		wtty = tty_port_tty_get(winch->port);
+		if (wtty == tty) {
+			free_winch(winch);
+			break;
+		}
+		tty_kref_put(wtty);
+	}
+	spin_unlock(&winch_handler_lock);
+}
+
+static void winch_cleanup(void)
+{
+	struct list_head *ele, *next;
+	struct winch *winch;
+
+	spin_lock(&winch_handler_lock);
+
+	list_for_each_safe(ele, next, &winch_handlers) {
+		winch = list_entry(ele, struct winch, list);
+		free_winch(winch);
+	}
+
+	spin_unlock(&winch_handler_lock);
+}
+__uml_exitcall(winch_cleanup);
+
+char *add_xterm_umid(char *base)
+{
+	char *umid, *title;
+	int len;
+
+	umid = get_umid();
+	if (*umid == '\0')
+		return base;
+
+	len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
+	title = kmalloc(len, GFP_KERNEL);
+	if (title == NULL) {
+		printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
+		return base;
+	}
+
+	snprintf(title, len, "%s (%s)", base, umid);
+	return title;
+}
-- 
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