From 6f1de6b70d857d5e316ae6fd908f52818b827b08 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 20 Jun 2016 15:02:40 +0200
Subject: [PATCH] char: change qemu_chr_fe_add_watch to return unsigned
g_source_attach can return any value between 1 and UINT_MAX if you let
QEMU run long enough. However, qemu_chr_fe_add_watch can also return
a negative errno value when the device is disconnected or does not
support chr_add_watch. Change it to return zero to avoid overloading
these values.
Fix the cadence_uart which asserts in this case (easily obtained with
"-serial pty").
Tested-by: Bret Ketchum <bcketchum@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/char/cadence_uart.c | 9 ++++++---
include/sysemu/char.h | 16 ++++++++++++++--
net/vhost-user.c | 2 +-
qemu-char.c | 8 ++++----
4 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
index c856fc30b2..65179fa500 100644
--- a/hw/char/cadence_uart.c
+++ b/hw/char/cadence_uart.c
@@ -292,9 +292,12 @@ static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count);
if (s->tx_count) {
- int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
- cadence_uart_xmit, s);
- assert(r);
+ guint r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
+ cadence_uart_xmit, s);
+ if (!r) {
+ s->tx_count = 0;
+ return FALSE;
+ }
}
uart_update_status(s);
diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index 1eb2d0f309..57df10aa00 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -221,8 +221,20 @@ void qemu_chr_fe_event(CharDriverState *s, int event);
void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
-int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
- GIOFunc func, void *user_data);
+/**
+ * @qemu_chr_fe_add_watch:
+ *
+ * If the backend is connected, create and add a #GSource that fires
+ * when the given condition (typically G_IO_OUT|G_IO_HUP or G_IO_HUP)
+ * is active; return the #GSource's tag. If it is disconnected,
+ * return 0.
+ *
+ * @cond the condition to poll for
+ * @func the function to call when the condition happens
+ * @user_data the opaque pointer to pass to @func
+ */
+guint qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
+ GIOFunc func, void *user_data);
/**
* @qemu_chr_fe_write:
diff --git a/net/vhost-user.c b/net/vhost-user.c
index d72ce9b490..636899a877 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -22,7 +22,7 @@ typedef struct VhostUserState {
NetClientState nc;
CharDriverState *chr;
VHostNetState *vhost_net;
- int watch;
+ guint watch;
uint64_t acked_features;
} VhostUserState;
diff --git a/qemu-char.c b/qemu-char.c
index 84f49acbac..8575c54c98 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3966,19 +3966,19 @@ void qemu_chr_fe_event(struct CharDriverState *chr, int event)
}
}
-int qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
- GIOFunc func, void *user_data)
+guint qemu_chr_fe_add_watch(CharDriverState *s, GIOCondition cond,
+ GIOFunc func, void *user_data)
{
GSource *src;
guint tag;
if (s->chr_add_watch == NULL) {
- return -ENOSYS;
+ return 0;
}
src = s->chr_add_watch(s, cond);
if (!src) {
- return -EINVAL;
+ return 0;
}
g_source_set_callback(src, (GSourceFunc)func, user_data, NULL);