Re: [PATCH BlueZ v5 4/7] shared/uinput-util: extract uinput utility function from AVCTP

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

Hi Pauli,

On Thu, Dec 11, 2025 at 3:16 PM Pauli Virtanen <pav@iki.fi> wrote:
>
> Extract uinput utility function from AVCTP to src/shared so that it can
> be reused for MCS.
> ---
>  Makefile.am              |   4 +-
>  src/shared/uinput-util.c | 191 +++++++++++++++++++++++++++++++++++++++
>  src/shared/uinput-util.h |  31 +++++++
>  3 files changed, 225 insertions(+), 1 deletion(-)
>  create mode 100644 src/shared/uinput-util.c
>  create mode 100644 src/shared/uinput-util.h
>
> diff --git a/Makefile.am b/Makefile.am
> index ba0262d5f..4c7177886 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -247,7 +247,9 @@ shared_sources = src/shared/io.h src/shared/timeout.h \
>                         src/shared/lc3.h src/shared/tty.h \
>                         src/shared/bap-defs.h \
>                         src/shared/asha.h src/shared/asha.c \
> -                       src/shared/battery.h src/shared/battery.c
> +                       src/shared/battery.h src/shared/battery.c \
> +                       src/shared/uinput-util.h \
> +                       src/shared/uinput-util.c
>
>  if READLINE
>  shared_sources += src/shared/shell.c src/shared/shell.h
> diff --git a/src/shared/uinput-util.c b/src/shared/uinput-util.c
> new file mode 100644
> index 000000000..4e9644661
> --- /dev/null
> +++ b/src/shared/uinput-util.c
> @@ -0,0 +1,191 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + *
> + *  BlueZ - Bluetooth protocol stack for Linux
> + *
> + *  Copyright (C) 2006-2010  Nokia Corporation
> + *  Copyright (C) 2004-2010  Marcel Holtmann <marcel@holtmann.org>
> + *  Copyright (C) 2011  Texas Instruments, Inc.
> + *
> + *
> + */
> +
> +#ifdef HAVE_CONFIG_H
> +#include <config.h>
> +#endif
> +
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdarg.h>
> +#include <linux/uinput.h>
> +
> +#include "bluetooth/bluetooth.h"
> +
> +#include "src/shared/util.h"
> +#include "src/shared/uinput-util.h"
> +
> +
> +#define DBG(uinput, fmt, arg...) \
> +       uinput_debug(uinput->debug_func, uinput->debug_data, "%s:%s() " fmt, \
> +                                               __FILE__, __func__, ## arg)
> +
> +struct bt_uinput {
> +       int fd;
> +       bt_uinput_debug_func_t debug_func;
> +       void *debug_data;
> +};
> +
> +static void uinput_debug(bt_uinput_debug_func_t debug_func, void *debug_data,
> +                                                       const char *format, ...)
> +{
> +       va_list ap;
> +
> +       if (!debug_func || !format)
> +               return;
> +
> +       va_start(ap, format);
> +       util_debug_va(debug_func, debug_data, format, ap);
> +       va_end(ap);
> +}
> +
> +static int send_event(int fd, uint16_t type, uint16_t code, int32_t value)
> +{
> +       struct input_event event;
> +
> +       memset(&event, 0, sizeof(event));
> +       event.type      = type;
> +       event.code      = code;
> +       event.value     = value;
> +
> +       return write(fd, &event, sizeof(event));
> +}
> +
> +void bt_uinput_send_key(struct bt_uinput *uinput, uint16_t key, bool pressed)
> +{
> +       if (!uinput)
> +               return;
> +
> +       DBG(uinput, "%d", key);
> +
> +       send_event(uinput->fd, EV_KEY, key, pressed ? 1 : 0);
> +       send_event(uinput->fd, EV_SYN, SYN_REPORT, 0);
> +}
> +
> +struct bt_uinput *bt_uinput_new(const char *name, const char *suffix,
> +                                       const bdaddr_t *addr,
> +                                       const struct input_id *dev_id,
> +                                       const struct bt_uinput_key_map *key_map,
> +                                       bt_uinput_debug_func_t debug,
> +                                       void *user_data)
> +{
> +       struct bt_uinput *uinput;
> +       struct uinput_user_dev dev;
> +       int fd, err, i;
> +       char src[18];
> +
> +       uinput = new0(struct bt_uinput, 1);
> +       uinput->debug_func = debug;
> +       uinput->debug_data = user_data;
> +
> +       fd = open("/dev/uinput", O_RDWR);
> +       if (fd < 0) {
> +               fd = open("/dev/input/uinput", O_RDWR);
> +               if (fd < 0) {
> +                       fd = open("/dev/misc/uinput", O_RDWR);
> +                       if (fd < 0) {
> +                               err = errno;
> +                               DBG(uinput, "Can't open input device: %s (%d)",
> +                                                       strerror(err), err);
> +                               free(uinput);

It is probably worth reordering the uinput allocation so it is after
the open, that way we don't need to free on bail out.

> +                               errno = err;
> +                               return NULL;
> +                       }
> +               }
> +       }
> +
> +       memset(&dev, 0, sizeof(dev));
> +
> +       if (name)
> +               snprintf(dev.name, UINPUT_MAX_NAME_SIZE, "%s", name);
> +
> +       if (suffix) {
> +               int len, slen;
> +
> +               len = strlen(dev.name);
> +               slen = strlen(suffix);
> +
> +               /* If name + suffix don't fit, truncate the name, then add the
> +                * suffix.
> +                */
> +               if (slen >= UINPUT_MAX_NAME_SIZE)
> +                       slen = UINPUT_MAX_NAME_SIZE - 1;
> +               if (len > UINPUT_MAX_NAME_SIZE - slen - 1)
> +                       len = UINPUT_MAX_NAME_SIZE - slen - 1;
> +
> +               snprintf(dev.name + len, UINPUT_MAX_NAME_SIZE - len,
> +                                                               "%s", suffix);
> +       }
> +
> +       if (dev_id) {
> +               dev.id.bustype = dev_id->bustype;
> +               dev.id.vendor = dev_id->vendor;
> +               dev.id.product = dev_id->product;
> +               dev.id.version = dev_id->version;
> +       } else {
> +               dev.id.bustype = BUS_VIRTUAL;
> +       }
> +
> +       if (write(fd, &dev, sizeof(dev)) < 0) {
> +               err = errno;
> +               DBG(uinput, "Can't write device information: %s (%d)",
> +                                                       strerror(err), err);
> +               close(fd);
> +               free(uinput);
> +               errno = err;
> +               return NULL;
> +       }
> +
> +       ioctl(fd, UI_SET_EVBIT, EV_KEY);
> +       ioctl(fd, UI_SET_EVBIT, EV_REL);
> +       ioctl(fd, UI_SET_EVBIT, EV_REP);
> +       ioctl(fd, UI_SET_EVBIT, EV_SYN);
> +
> +       ba2strlc(addr, src);
> +       ioctl(fd, UI_SET_PHYS, src);
> +
> +       for (i = 0; key_map[i].name != NULL; i++)
> +               ioctl(fd, UI_SET_KEYBIT, key_map[i].uinput);
> +
> +       if (ioctl(fd, UI_DEV_CREATE, NULL) < 0) {
> +               err = errno;
> +               DBG(uinput, "Can't create uinput device: %s (%d)",
> +                                                       strerror(err), err);
> +               close(fd);
> +               free(uinput);
> +               errno = err;
> +               return NULL;
> +       }
> +
> +       send_event(fd, EV_REP, REP_DELAY, 300);
> +
> +       DBG(uinput, "%p", uinput);
> +
> +       uinput->fd = fd;
> +       return uinput;
> +}
> +
> +void bt_uinput_destroy(struct bt_uinput *uinput)
> +{
> +       if (!uinput)
> +               return;
> +
> +       DBG(uinput, "%p", uinput);
> +
> +       ioctl(uinput->fd, UI_DEV_DESTROY);
> +       close(uinput->fd);
> +       free(uinput);
> +}
> diff --git a/src/shared/uinput-util.h b/src/shared/uinput-util.h
> new file mode 100644
> index 000000000..fb8f7e6bd
> --- /dev/null
> +++ b/src/shared/uinput-util.h
> @@ -0,0 +1,31 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later

In theory we should only place LGPL code into src/shared, now I see we
are copying some code thus it should continue using the same license
as the original code, but perhaps it is worth reworking the copied
code since it is quite simple and I think it is worth it to not
contaminate shared library with GPL.

> +/*
> + *
> + *  BlueZ - Bluetooth protocol stack for Linux
> + *
> + *  Copyright (C) 2006-2010  Nokia Corporation
> + *  Copyright (C) 2004-2010  Marcel Holtmann <marcel@holtmann.org>
> + *  Copyright (C) 2011  Texas Instruments, Inc.
> + *
> + *
> + */
> +
> +struct bt_uinput;
> +
> +struct bt_uinput_key_map {
> +       const char *name;
> +       unsigned int code;
> +       uint16_t uinput;
> +};
> +
> +typedef void (*bt_uinput_debug_func_t)(const char *str, void *user_data);
> +
> +struct bt_uinput *bt_uinput_new(const char *name, const char *suffix,
> +                                       const bdaddr_t *addr,
> +                                       const struct input_id *dev_id,
> +                                       const struct bt_uinput_key_map *key_map,
> +                                       bt_uinput_debug_func_t debug,
> +                                       void *user_data);

I'd leave the debug function to be initialized with its own function
(e.g. bt_uinput_set_debug).

> +void bt_uinput_destroy(struct bt_uinput *uinput);
> +
> +void bt_uinput_send_key(struct bt_uinput *uinput, uint16_t key, bool pressed);
> --
> 2.51.1
>
>


-- 
Luiz Augusto von Dentz