decent coding session

2 files changed, 201 insertions, 12 deletions

diff --git a/kernel/drivers/tty/ldisc.c b/kernel/drivers/tty/ldisc.c
index eaf0440..dd67706 100644
--- a/kernel/drivers/tty/ldisc.c
+++ b/kernel/drivers/tty/ldisc.c
@@ -16,7 +16,19 @@
  */
 void ldisc_init(ldisc_t *ldisc)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: ldisc_init");
+    // NOT_YET_IMPLEMENTED("DRIVERS: ldisc_init");
+
+    // reset static buffer
+    memset(ldisc->ldisc_buffer, 0, LDISC_BUFFER_SIZE);
+
+    // init the queue
+    sched_queue_init(&ldisc->ldisc_read_queue);
+
+    // fill in other fields
+    ldisc->ldisc_head = 0;
+    ldisc->ldisc_tail = 0;
+    ldisc->ldisc_cooked = 0;
+    ldisc->ldisc_full = 0; // 0 not full
 }
 
 /**
@@ -33,8 +45,31 @@ void ldisc_init(ldisc_t *ldisc)
  */
 long ldisc_wait_read(ldisc_t *ldisc)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: ldisc_wait_read");
-    return -1;
+    // NOT_YET_IMPLEMENTED("DRIVERS: ldisc_wait_read");
+
+    // if it's full, return 0
+    if (ldisc->ldisc_full)
+    {
+        return 0;
+    }
+
+    // while there are no need chars to be read, sleep
+    // TODO: check if this is the right condition
+    while ( 
+        (ldisc->ldisc_head == ldisc->ldisc_tail) 
+        || 
+        (ldisc->ldisc_head == ldisc->ldisc_cooked)
+        )
+    {
+        long ret = sched_cancellable_sleep_on(&ldisc->ldisc_read_queue);
+        if (ret != 0)
+        {
+            return ret;
+        }
+    }
+
+    // if we are here, it means we have new chars to read
+    return 0;
 }
 
 /**
@@ -54,8 +89,51 @@ long ldisc_wait_read(ldisc_t *ldisc)
  */
 size_t ldisc_read(ldisc_t *ldisc, char *buf, size_t count)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: ldisc_read");
-    return 0;
+    // NOT_YET_IMPLEMENTED("DRIVERS: ldisc_read");
+
+    // read from ldisc buffer to buf
+    size_t i = 0;
+    while (i < count)
+    {
+        // if we have new chars to read
+        if (ldisc->ldisc_head != ldisc->ldisc_tail)
+        {
+            // if we encounter a new line symbol
+            if (ldisc->ldisc_buffer[ldisc->ldisc_head] == '\n')
+            {
+                buf[i] = ldisc->ldisc_buffer[ldisc->ldisc_head];
+                ldisc->ldisc_head = (ldisc->ldisc_head + 1) % LDISC_BUFFER_SIZE;
+                i++;
+                break;
+            }
+            // if we encounter an EOT
+            else if (ldisc->ldisc_buffer[ldisc->ldisc_head] == EOT)
+            {
+                break;
+            }
+            // if we encounter an ETX
+            else if (ldisc->ldisc_buffer[ldisc->ldisc_head] == ETX)
+            {
+                // clear uncooked portion of the line
+                ldisc->ldisc_head = ldisc->ldisc_cooked;
+                break;
+            }
+            // if we encounter a normal char
+            else
+            {
+                buf[i] = ldisc->ldisc_buffer[ldisc->ldisc_head];
+                ldisc->ldisc_head = (ldisc->ldisc_head + 1) % LDISC_BUFFER_SIZE;
+                i++;
+            }
+        }
+        else
+        {
+            break;
+        }
+    }
+
+    // return the number of bytes read
+    return i;
 }
 
 /**
@@ -103,7 +181,66 @@ size_t ldisc_read(ldisc_t *ldisc, char *buf, size_t count)
  */
 void ldisc_key_pressed(ldisc_t *ldisc, char c)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: ldisc_key_pressed");
+    // NOT_YET_IMPLEMENTED("DRIVERS: ldisc_key_pressed");
+
+    // if the buffer is full, ignore the incoming char
+    if (ldisc->ldisc_full)
+    {
+        return;
+    }
+
+    switch (c)
+    {
+    case '\b':
+        // if there is a character to remove
+        if (ldisc->ldisc_head != ldisc->ldisc_tail)
+        {
+            // remove the last char
+            ldisc->ldisc_head = (ldisc->ldisc_head - 1 + LDISC_BUFFER_SIZE) % LDISC_BUFFER_SIZE;
+            // emit a `\b` to the vterminal
+            vterminal_write(ldisc_to_tty(ldisc), "\b", 1);
+        }
+        break;
+
+    case '\n':
+        // emit a `\n` to the vterminal
+        vterminal_write(ldisc_to_tty(ldisc), "\n", 1);
+
+        // add the new char to the buffer
+        ldisc->ldisc_buffer[ldisc->ldisc_tail] = c;
+        ldisc->ldisc_tail = (ldisc->ldisc_tail + 1) % LDISC_BUFFER_SIZE;
+        // set the buffer to full
+        ldisc->ldisc_full = 1;
+
+        // wake up the thread that is sleeping on the wait queue of the line discipline
+        sched_wakeup_on(&ldisc->ldisc_read_queue, 0);
+        break;
+
+    case EOT:
+        // add the new char to the buffer
+        ldisc->ldisc_buffer[ldisc->ldisc_tail] = c;
+        ldisc->ldisc_tail = (ldisc->ldisc_tail + 1) % LDISC_BUFFER_SIZE;
+        // set the buffer to full
+        ldisc->ldisc_full = 1;
+
+        // cook the buffer
+        ldisc->ldisc_cooked = ldisc->ldisc_tail;
+
+        // wake up the thread that is sleeping on the wait queue of the line discipline
+        sched_wakeup_on(&ldisc->ldisc_read_queue, 0);
+        break;
+
+    case ETX:
+        // clear uncooked portion of the line
+        ldisc->ldisc_head = ldisc->ldisc_cooked;
+        break;
+
+    default:
+        // if none applies, fallback to vterminal_key_pressed
+        vterminal_key_pressed(ldisc_to_tty(ldisc));
+
+        break;
+    }
 }
 
 /**
@@ -115,6 +252,18 @@ void ldisc_key_pressed(ldisc_t *ldisc, char c)
  */
 size_t ldisc_get_current_line_raw(ldisc_t *ldisc, char *s)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: ldisc_get_current_line_raw");
-    return 0;
+    // NOT_YET_IMPLEMENTED("DRIVERS: ldisc_get_current_line_raw");
+
+    // copy the raw part of the line discipline buffer into the buffer provided
+    size_t i = 0;
+    size_t j = ldisc->ldisc_cooked;
+    while (j != ldisc->ldisc_head)
+    {
+        s[i] = ldisc->ldisc_buffer[j];
+        j = (j + 1) % LDISC_BUFFER_SIZE;
+        i++;
+    }
+
+    // return the number of bytes copied
+    return i;
 }
diff --git a/kernel/drivers/tty/tty.c b/kernel/drivers/tty/tty.c
index 3694877..c47a582 100644
--- a/kernel/drivers/tty/tty.c
+++ b/kernel/drivers/tty/tty.c
@@ -69,8 +69,29 @@ void tty_init()
  */
 ssize_t tty_read(chardev_t *cdev, size_t pos, void *buf, size_t count)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: tty_read");
-    return -1;
+    // NOT_YET_IMPLEMENTED("DRIVERS: tty_read");
+
+    // get the mapped tty
+    tty_t *tty = cd_to_tty(cdev);
+
+    // set the IPL to INTR_KEYBOARD
+    uint8_t prev_ipl = intr_setipl(INTR_KEYBOARD);
+
+    // lock the read mutex of the tty
+    kmutex_lock(&tty->tty_read_mutex);
+
+    // wait until there is something in the line discipline's buffer
+    ldisc_wait_read(&tty->tty_ldisc);
+
+    // read from the ldisc's buffer if there are new characters
+    ssize_t bytes_read = ldisc_read(&tty->tty_ldisc, buf, count);
+    // unlock the read mutex of the tty
+    kmutex_unlock(&tty->tty_read_mutex);
+    
+    // revert the IPL
+    intr_setipl(prev_ipl);
+
+    return bytes_read;
 }
 
 /**
@@ -88,8 +109,27 @@ ssize_t tty_read(chardev_t *cdev, size_t pos, void *buf, size_t count)
  */
 ssize_t tty_write(chardev_t *cdev, size_t pos, const void *buf, size_t count)
 {
-    NOT_YET_IMPLEMENTED("DRIVERS: tty_write");
-    return -1;
+    // NOT_YET_IMPLEMENTED("DRIVERS: tty_write");
+
+    // get the mapped tty
+    tty_t *tty = cd_to_tty(cdev);
+
+    // set the IPL to INTR_KEYBOARD
+    uint8_t prev_ipl = intr_setipl(INTR_KEYBOARD);
+    
+    // lock the write mutex of the tty
+    kmutex_lock(&tty->tty_write_mutex);
+
+    // write to the terminal
+    size_t bytes_written = vterminal_write(&tty->tty_vterminal, buf, count);
+
+    // unlock the write mutex of the tty
+    kmutex_unlock(&tty->tty_write_mutex);
+    // revert the IPL
+    intr_setipl(prev_ipl);
+
+
+    return bytes_written;
 }
 
 static void tty_receive_char_multiplexer(uint8_t c)