1 files changed, 145 insertions, 4 deletions

diff --git a/vl.c b/vl.c
index a60fbae..bb92776 100644
--- a/vl.c
+++ b/vl.c
@@ -2464,21 +2464,162 @@ void cfmakeraw (struct termios *termios_p)
 #endif
 
 #if defined(__linux__) || defined(__sun__)
+
+typedef struct {
+    int fd;
+    int connected;
+    int polling;
+    int read_bytes;
+    QEMUTimer *timer;
+} PtyCharDriver;
+
+static void pty_chr_update_read_handler(CharDriverState *chr);
+static void pty_chr_state(CharDriverState *chr, int connected);
+
+static int pty_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
+{
+    PtyCharDriver *s = chr->opaque;
+
+    if (!s->connected) {
+        /* guest sends data, check for (re-)connect */
+        pty_chr_update_read_handler(chr);
+        return 0;
+    }
+    return unix_write(s->fd, buf, len);
+}
+
+static int pty_chr_read_poll(void *opaque)
+{
+    CharDriverState *chr = opaque;
+    PtyCharDriver *s = chr->opaque;
+
+    s->read_bytes = qemu_chr_can_read(chr);
+    return s->read_bytes;
+}
+
+static void pty_chr_read(void *opaque)
+{
+    CharDriverState *chr = opaque;
+    PtyCharDriver *s = chr->opaque;
+    int size, len;
+    uint8_t buf[1024];
+
+    len = sizeof(buf);
+    if (len > s->read_bytes)
+        len = s->read_bytes;
+    if (len == 0)
+        return;
+    size = read(s->fd, buf, len);
+    if ((size == -1 && errno == EIO) ||
+        (size == 0)) {
+        pty_chr_state(chr, 0);
+        return;
+    }
+    if (size > 0) {
+        pty_chr_state(chr, 1);
+        qemu_chr_read(chr, buf, size);
+    }
+}
+
+static void pty_chr_update_read_handler(CharDriverState *chr)
+{
+    PtyCharDriver *s = chr->opaque;
+
+    qemu_set_fd_handler2(s->fd, pty_chr_read_poll,
+                         pty_chr_read, NULL, chr);
+    s->polling = 1;
+    /*
+     * Short timeout here: just need wait long enougth that qemu makes
+     * it through the poll loop once.  When reconnected we want a
+     * short timeout so we notice it almost instantly.  Otherwise
+     * read() gives us -EIO instantly, making pty_chr_state() reset the
+     * timeout to the normal (much longer) poll interval before the
+     * timer triggers.
+     */
+    qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 10);
+}
+
+static void pty_chr_state(CharDriverState *chr, int connected)
+{
+    PtyCharDriver *s = chr->opaque;
+
+    if (!connected) {
+        qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
+        s->connected = 0;
+        s->polling = 0;
+        /* (re-)connect poll interval for idle guests: once per second.
+         * We check more frequently in case the guests sends data to
+         * the virtual device linked to our pty. */
+        qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 1000);
+    } else {
+        if (!s->connected)
+            qemu_chr_reset(chr);
+        s->connected = 1;
+    }
+}
+
+void pty_chr_timer(void *opaque)
+{
+    struct CharDriverState *chr = opaque;
+    PtyCharDriver *s = chr->opaque;
+
+    if (s->connected)
+        return;
+    if (s->polling) {
+        /* If we arrive here without polling being cleared due
+         * read returning -EIO, then we are (re-)connected */
+        pty_chr_state(chr, 1);
+        return;
+    }
+
+    /* Next poll ... */
+    pty_chr_update_read_handler(chr);
+}
+
+static void pty_chr_close(struct CharDriverState *chr)
+{
+    PtyCharDriver *s = chr->opaque;
+
+    qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
+    close(s->fd);
+    qemu_free(s);
+}
+
 static CharDriverState *qemu_chr_open_pty(void)
 {
+    CharDriverState *chr;
+    PtyCharDriver *s;
     struct termios tty;
-    int master_fd, slave_fd;
+    int slave_fd;
 
-    if (openpty(&master_fd, &slave_fd, NULL, NULL, NULL) < 0) {
+    chr = qemu_mallocz(sizeof(CharDriverState));
+    if (!chr)
+        return NULL;
+    s = qemu_mallocz(sizeof(PtyCharDriver));
+    if (!s) {
+        qemu_free(chr);
+        return NULL;
+    }
+
+    if (openpty(&s->fd, &slave_fd, NULL, NULL, NULL) < 0) {
         return NULL;
     }
 
     /* Set raw attributes on the pty. */
     cfmakeraw(&tty);
     tcsetattr(slave_fd, TCSAFLUSH, &tty);
+    close(slave_fd);
+
+    fprintf(stderr, "char device redirected to %s\n", ptsname(s->fd));
 
-    fprintf(stderr, "char device redirected to %s\n", ptsname(master_fd));
-    return qemu_chr_open_fd(master_fd, master_fd);
+    chr->opaque = s;
+    chr->chr_write = pty_chr_write;
+    chr->chr_update_read_handler = pty_chr_update_read_handler;
+    chr->chr_close = pty_chr_close;
+
+    s->timer = qemu_new_timer(rt_clock, pty_chr_timer, chr);
+
+    return chr;
 }
 
 static void tty_serial_init(int fd, int speed,