[PATCH 0/3] win32: Windows-specific fixes from the mailing list

[PATCH 0/3] win32: Windows-specific fixes from the mailing list

[Mohamed Mediouni]

It looks like these ought to be merged but were not, so
posting them again.

Gal Horowitz (2):
  tap-win32: cleanup leaked handles on tap close
  tap-win32: allocate separate tap state for each instance

Werner de Carne (1):
  serial COM: windows serial COM PollingFunc don't sleep

 chardev/char-win.c | 16 +++++++++------
 net/tap-win32.c    | 51 ++++++++++++++++++++++++++++++++++++----------
 2 files changed, 50 insertions(+), 17 deletions(-)

-- 
2.50.1 (Apple Git-155)

[PATCH 1/3] serial COM: windows serial COM PollingFunc don't sleep

[Mohamed Mediouni]

From: Werner de Carne <werner@carne.de>

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1802
Signed-off-by: Werner de Carne <werner@carne.de>
---
 chardev/char-win.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/chardev/char-win.c b/chardev/char-win.c
index fef45e83aa..f13d526e2f 100644
--- a/chardev/char-win.c
+++ b/chardev/char-win.c
@@ -28,7 +28,7 @@
 #include "qapi/error.h"
 #include "chardev/char-win.h"
 
-static void win_chr_read(Chardev *chr, DWORD len)
+static int win_chr_read(Chardev *chr, DWORD len)
 {
     WinChardev *s = WIN_CHARDEV(chr);
     int max_size = qemu_chr_be_can_write(chr);
@@ -40,7 +40,7 @@ static void win_chr_read(Chardev *chr, DWORD len)
         len = max_size;
     }
     if (len == 0) {
-        return;
+        return 0;
     }
 
     ZeroMemory(&s->orecv, sizeof(s->orecv));
@@ -56,6 +56,8 @@ static void win_chr_read(Chardev *chr, DWORD len)
     if (size > 0) {
         qemu_chr_be_write(chr, buf, size);
     }
+    
+    return size > 0 ? 1 : 0;
 }
 
 static int win_chr_serial_poll(void *opaque)
@@ -67,8 +69,9 @@ static int win_chr_serial_poll(void *opaque)
 
     ClearCommError(s->file, &comerr, &status);
     if (status.cbInQue > 0) {
-        win_chr_read(chr, status.cbInQue);
-        return 1;
+        if (win_chr_read(chr, status.cbInQue)) {
+			return 1;
+		}
     }
     return 0;
 }
@@ -147,8 +150,9 @@ int win_chr_pipe_poll(void *opaque)
 
     PeekNamedPipe(s->file, NULL, 0, NULL, &size, NULL);
     if (size > 0) {
-        win_chr_read(chr, size);
-        return 1;
+    	if (win_chr_read(chr, size)) {
+			return 1;
+		}
     }
     return 0;
 }
-- 
2.50.1 (Apple Git-155)

[PATCH 2/3] tap-win32: cleanup leaked handles on tap close

[Mohamed Mediouni]

From: Gal Horowitz <galush.horowitz@gmail.com>

Currently, all handles owned by a win32 tap are leaked on cleanup.
This commit ensures that the handles are properly closed upon tap
cleanup. A check for the return value of CreateThread is also added.

Signed-off-by: Gal Horowitz <galush.horowitz@gmail.com>
---
 net/tap-win32.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/net/tap-win32.c b/net/tap-win32.c
index 38baf90e0b..ae25e5a883 100644
--- a/net/tap-win32.c
+++ b/net/tap-win32.c
@@ -104,6 +104,7 @@ typedef struct tap_win32_overlapped {
     HANDLE output_queue_semaphore;
     HANDLE free_list_semaphore;
     HANDLE tap_semaphore;
+    HANDLE thread_handle;
     CRITICAL_SECTION output_queue_cs;
     CRITICAL_SECTION free_list_cs;
     OVERLAPPED read_overlapped;
@@ -589,6 +590,26 @@ static void tap_win32_free_buffer(tap_win32_overlapped_t *overlapped,
     put_buffer_on_free_list(overlapped, buffer);
 }
 
+static void tap_win32_close(tap_win32_overlapped_t *overlapped)
+{
+    TerminateThread(overlapped->thread_handle, 0);
+    CloseHandle(overlapped->thread_handle);
+
+    CloseHandle(overlapped->tap_semaphore);
+    CloseHandle(overlapped->free_list_semaphore);
+    CloseHandle(overlapped->output_queue_semaphore);
+
+    DeleteCriticalSection(&overlapped->free_list_cs);
+    DeleteCriticalSection(&overlapped->output_queue_cs);
+
+    CloseHandle(overlapped->write_event);
+    CloseHandle(overlapped->read_event);
+
+    CloseHandle(overlapped->handle);
+
+    g_free(overlapped);
+}
+
 static int tap_win32_open(tap_win32_overlapped_t **phandle,
                           const char *preferred_name)
 {
@@ -604,7 +625,6 @@ static int tap_win32_open(tap_win32_overlapped_t **phandle,
         unsigned long debug;
     } version;
     DWORD version_len;
-    DWORD idThread;
 
     if (preferred_name != NULL) {
         snprintf(name_buffer, sizeof(name_buffer), "%s", preferred_name);
@@ -642,15 +662,22 @@ static int tap_win32_open(tap_win32_overlapped_t **phandle,
     }
 
     if (!tap_win32_set_status(handle, TRUE)) {
+        CloseHandle(handle);
         return -1;
     }
 
     tap_win32_overlapped_init(&tap_overlapped, handle);
 
-    *phandle = &tap_overlapped;
+    tap_overlapped.thread_handle = CreateThread(NULL, 0,
+        tap_win32_thread_entry, (LPVOID)&tap_overlapped, 0, NULL);
+
+    if (tap_overlapped->thread_handle == NULL) {
+        tap_win32_close(tap_overlapped);
+        return -1;
+    }
+
+    *phandle = tap_overlapped;
 
-    CreateThread(NULL, 0, tap_win32_thread_entry,
-                 (LPVOID)&tap_overlapped, 0, &idThread);
     return 0;
 }
 
@@ -667,9 +694,8 @@ static void tap_cleanup(NetClientState *nc)
 
     qemu_del_wait_object(s->handle->tap_semaphore, NULL, NULL);
 
-    /* FIXME: need to kill thread and close file handle:
-       tap_win32_close(s);
-    */
+    tap_win32_close(s->handle);
+    s->handle = NULL;
 }
 
 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
-- 
2.50.1 (Apple Git-155)

[PATCH 3/3] tap-win32: allocate separate tap state for each instance

[Mohamed Mediouni]

From: Gal Horowitz <galush.horowitz@gmail.com>

A static global is incorrectly used as the tap state for all win32 taps
created. Instead, we now allocate per win32 tap.

Signed-off-by: Gal Horowitz <galush.horowitz@gmail.com>
---
 net/tap-win32.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/tap-win32.c b/net/tap-win32.c
index ae25e5a883..3d7227fcf4 100644
--- a/net/tap-win32.c
+++ b/net/tap-win32.c
@@ -115,8 +115,6 @@ typedef struct tap_win32_overlapped {
     tun_buffer_t* output_queue_back;
 } tap_win32_overlapped_t;
 
-static tap_win32_overlapped_t tap_overlapped;
-
 static tun_buffer_t* get_buffer_from_free_list(tap_win32_overlapped_t* const overlapped)
 {
     tun_buffer_t* buffer = NULL;
@@ -403,8 +401,10 @@ static int tap_win32_set_status(HANDLE handle, int status)
                 &status, sizeof (status), &len, NULL);
 }
 
-static void tap_win32_overlapped_init(tap_win32_overlapped_t* const overlapped, const HANDLE handle)
+static tap_win32_overlapped_t *tap_win32_overlapped_new(const HANDLE handle)
 {
+    tap_win32_overlapped_t *overlapped = g_new0(tap_win32_overlapped_t, 1);
+
     overlapped->handle = handle;
 
     overlapped->read_event = CreateEvent(NULL, FALSE, FALSE, NULL);
@@ -455,6 +455,8 @@ static void tap_win32_overlapped_init(tap_win32_overlapped_t* const overlapped,
     overlapped->tap_semaphore = CreateSemaphore(NULL, 0, TUN_MAX_BUFFER_COUNT, NULL);
     if(!overlapped->tap_semaphore)
         fprintf(stderr, "error creating tap_semaphore.\n");
+
+    return overlapped;
 }
 
 static int tap_win32_write(tap_win32_overlapped_t *overlapped,
@@ -625,6 +627,7 @@ static int tap_win32_open(tap_win32_overlapped_t **phandle,
         unsigned long debug;
     } version;
     DWORD version_len;
+    tap_win32_overlapped_t *tap_overlapped = NULL;
 
     if (preferred_name != NULL) {
         snprintf(name_buffer, sizeof(name_buffer), "%s", preferred_name);
@@ -666,10 +669,10 @@ static int tap_win32_open(tap_win32_overlapped_t **phandle,
         return -1;
     }
 
-    tap_win32_overlapped_init(&tap_overlapped, handle);
+    tap_overlapped = tap_win32_overlapped_new(handle);
 
-    tap_overlapped.thread_handle = CreateThread(NULL, 0,
-        tap_win32_thread_entry, (LPVOID)&tap_overlapped, 0, NULL);
+    tap_overlapped->thread_handle = CreateThread(NULL, 0,
+        tap_win32_thread_entry, (LPVOID)tap_overlapped, 0, NULL);
 
     if (tap_overlapped->thread_handle == NULL) {
         tap_win32_close(tap_overlapped);
-- 
2.50.1 (Apple Git-155)

Re: [PATCH 1/3] serial COM: windows serial COM PollingFunc don't sleep

[Marc-André Lureau]

Hi

On Mon, Apr 13, 2026 at 8:56 PM Mohamed Mediouni
<mohamed@unpredictable.fr> wrote:
>
> From: Werner de Carne <werner@carne.de>
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1802
> Signed-off-by: Werner de Carne <werner@carne.de>
> ---
>  chardev/char-win.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/chardev/char-win.c b/chardev/char-win.c
> index fef45e83aa..f13d526e2f 100644
> --- a/chardev/char-win.c
> +++ b/chardev/char-win.c
> @@ -28,7 +28,7 @@
>  #include "qapi/error.h"
>  #include "chardev/char-win.h"
>
> -static void win_chr_read(Chardev *chr, DWORD len)
> +static int win_chr_read(Chardev *chr, DWORD len)
>  {
>      WinChardev *s = WIN_CHARDEV(chr);
>      int max_size = qemu_chr_be_can_write(chr);
> @@ -40,7 +40,7 @@ static void win_chr_read(Chardev *chr, DWORD len)
>          len = max_size;
>      }
>      if (len == 0) {
> -        return;
> +        return 0;
>      }
>
>      ZeroMemory(&s->orecv, sizeof(s->orecv));
> @@ -56,6 +56,8 @@ static void win_chr_read(Chardev *chr, DWORD len)
>      if (size > 0) {
>          qemu_chr_be_write(chr, buf, size);
>      }
> +
> +    return size > 0 ? 1 : 0;
>  }
>
>  static int win_chr_serial_poll(void *opaque)
> @@ -67,8 +69,9 @@ static int win_chr_serial_poll(void *opaque)
>
>      ClearCommError(s->file, &comerr, &status);
>      if (status.cbInQue > 0) {
> -        win_chr_read(chr, status.cbInQue);
> -        return 1;
> +        if (win_chr_read(chr, status.cbInQue)) {
> +                       return 1;

indent is off

> +               }
>      }
>      return 0;
>  }
> @@ -147,8 +150,9 @@ int win_chr_pipe_poll(void *opaque)
>
>      PeekNamedPipe(s->file, NULL, 0, NULL, &size, NULL);
>      if (size > 0) {
> -        win_chr_read(chr, size);
> -        return 1;
> +       if (win_chr_read(chr, size)) {
> +                       return 1;

same

Otherwise
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> +               }
>      }
>      return 0;
>  }
> --
> 2.50.1 (Apple Git-155)
>
>


-- 
Marc-André Lureau