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Add support for tablet/touchscreen devices
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Add 'absinfo' field to the protocol handshake, containing array of
input_absinfo structures (ABS_CNT of them). Since the first message
contains a size of input_proxy_device_caps_msg structure, both forward
and backward compatibility can be achieved.

On receiver part, assume given absolute axis present only if both
relevant absbit is set and min/max info is provided. And of course only
if current policy allows it (--tablet option). Then register present
axis in uinput driver. While registering axis, set also other info
(precission, fuzz, flat), as it may be needed for touchscreen devices.
--tablet option allows all absolute axis and selected touchscreen/tablet
related buttons. According to tests, BTN_TOUCH is most commonly used.
Handling events is already in place - no changes are needed.

On sending part, extract absinfo from actual device and send that
information to receiver. No other changes are needed.

Fixes QubesOS/qubes-issues#2281
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@marmarek
marmarek committed Apr 1, 2018
1 parent 67edd36 commit 06b20b0
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Showing 3 changed files with 110 additions and 3 deletions.
90 changes: 87 additions & 3 deletions src/input-proxy-receiver.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ struct options {
int vendor;
int product;
struct input_proxy_device_caps caps;
struct input_absinfo absinfo[ABS_CNT];
};

void long_and(unsigned long *dst, unsigned long *src, size_t longs_count) {
Expand Down Expand Up @@ -61,7 +62,7 @@ void long_set_bit(unsigned long *bitfield, int bit, size_t bitfield_size) {
int receive_and_validate_caps(struct options *opt) {
struct input_proxy_device_caps_msg untrusted_caps_msg;
struct input_proxy_hello untrusted_hello;
size_t caps_size;
size_t caps_size, i;
int rc;

rc = read_all(0, &untrusted_hello, sizeof(untrusted_hello));
Expand Down Expand Up @@ -151,6 +152,29 @@ int receive_and_validate_caps(struct options *opt) {
opt->name[sizeof(untrusted_caps_msg.name)-1] = 0;
}

/* copy input_absinfo for EV_ABS; if given info is missing, disable that
* axis */
for (i = 0; i < ABS_CNT; i++) {
if (LONG_TEST_BIT(opt->caps.absbit, i)) {
if (!untrusted_caps_msg.absinfo[i].minimum &&
!untrusted_caps_msg.absinfo[i].maximum) {
/* no axis limits are provided, disable it */
opt->caps.absbit[i / BITS_PER_LONG] &= ~(1UL<<(i & (BITS_PER_LONG-1)));
continue;
}
/* here is place for some validation of axis data, if we come up
* with any - in addition to those done by Linux kernel, and later
* input driver */
opt->absinfo[i].value = untrusted_caps_msg.absinfo[i].value;
opt->absinfo[i].minimum = untrusted_caps_msg.absinfo[i].minimum;
opt->absinfo[i].maximum = untrusted_caps_msg.absinfo[i].maximum;
opt->absinfo[i].resolution =
untrusted_caps_msg.absinfo[i].resolution;
opt->absinfo[i].fuzz = untrusted_caps_msg.absinfo[i].fuzz;
opt->absinfo[i].flat = untrusted_caps_msg.absinfo[i].flat;
}
}

return 1;
}

Expand All @@ -168,6 +192,26 @@ int send_bits(int fd, int ioctl_num, unsigned long *bits, size_t bits_count) {
return 0;
}

#if UINPUT_VERSION >= 5
int send_absinfo(int fd,
unsigned long abs_bits[BITS_TO_LONGS(ABS_CNT)],
struct input_absinfo *absinfo) {
struct uinput_abs_setup absinfo_setup;
size_t i;

for (i = 0; i < ABS_CNT; i++) {
if (long_test_bit(abs_bits, i, BITS_TO_LONGS(ABS_CNT))) {
absinfo_setup.code = i;
absinfo_setup.absinfo = absinfo[i];
if (ioctl(fd, UI_ABS_SETUP, &absinfo_setup) == -1) {
perror("ioctl set absinfo");
return -1;
}
}
}
return 0;
}
#endif

int register_device(struct options *opt, int fd) {
#if UINPUT_VERSION >= 5
Expand Down Expand Up @@ -230,11 +274,26 @@ int register_device(struct options *opt, int fd) {
size_t i;

/* fallback to old uinput_user_dev method */
/* TODO: support for uinput_dev.abs(min|max) */
if (LONG_TEST_BIT(opt->caps.evbit, EV_ABS)) {
for (i = 0; i < ABS_CNT; i++) {
if (LONG_TEST_BIT(opt->caps.absbit, i)) {
uinput_dev.absmax[i] = opt->absinfo[i].maximum;
uinput_dev.absmin[i] = opt->absinfo[i].minimum;
uinput_dev.absfuzz[i] = opt->absinfo[i].fuzz;
uinput_dev.absflat[i] = opt->absinfo[i].flat;
}
}
}
if (write_all(fd, &uinput_dev, sizeof(uinput_dev)) == -1) {
return -1;
}
#if UINPUT_VERSION >= 5
} else {
/* new method worked, send absinfo using new method */
if (!rc && LONG_TEST_BIT(opt->caps.evbit, EV_ABS))
rc = send_absinfo(fd, opt->caps.absbit, opt->absinfo);
if (rc == -1)
return -1;
}
#endif
if (ioctl(fd, UI_DEV_CREATE) == -1) {
Expand Down Expand Up @@ -407,7 +466,32 @@ int parse_options(struct options *opt, int argc, char **argv) {
break;
case 't':
LONG_SET_BIT(opt->caps.evbit, EV_ABS);
/* TODO: absmax */
/* TODO: some configuration for that */
memset(opt->caps.absbit, 0xff, sizeof(opt->caps.absbit));
LONG_SET_BIT(opt->caps.evbit, EV_KEY);
LONG_SET_BIT(opt->caps.keybit, BTN_DIGI);
LONG_SET_BIT(opt->caps.keybit, BTN_TOUCH);
LONG_SET_BIT(opt->caps.keybit, BTN_LEFT);
LONG_SET_BIT(opt->caps.keybit, BTN_RIGHT);
LONG_SET_BIT(opt->caps.keybit, BTN_MIDDLE);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_PEN);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_RUBBER);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_BRUSH);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_PENCIL);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_AIRBRUSH);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_FINGER);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_MOUSE);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_LENS);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_DOUBLETAP);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_TRIPLETAP);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_QUADTAP);
LONG_SET_BIT(opt->caps.keybit, BTN_TOOL_QUINTTAP);
LONG_SET_BIT(opt->caps.keybit, BTN_STYLUS);
LONG_SET_BIT(opt->caps.keybit, BTN_STYLUS2);
/* not available with older headers */
# ifdef BTN_STYLUS3
LONG_SET_BIT(opt->caps.keybit, BTN_STYLUS3);
# endif
break;
case 'n':
opt->name = optarg;
Expand Down
10 changes: 10 additions & 0 deletions src/input-proxy-sender.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,16 @@ int send_caps(int fd) {
caps_msg.name[sizeof(caps_msg.name)-1] = 0;
}

for (i = 0; i < ABS_CNT; i++) {
if (caps.absbit[i / BITS_PER_LONG] & (1UL<<(i & (BITS_PER_LONG-1)))) {
rc = ioctl(fd, EVIOCGABS(i), &caps_msg.absinfo[i]);
if (rc == -1) {
perror("ioctl get absinfo");
return -1;
}
}
}

rc = write_all(1, &hello, sizeof(hello));
if (rc == -1)
return rc;
Expand Down
13 changes: 13 additions & 0 deletions src/protocol.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,10 +27,23 @@ struct input_proxy_device_caps {
unsigned long swbit[BITS_TO_LONGS(SW_CNT)];
};

/* linux/input/h:
*
* struct input_absinfo {
* __s32 value;
* __s32 minimum;
* __s32 maximum;
* __s32 fuzz;
* __s32 flat;
* __s32 resolution;
* };
*/

struct input_proxy_device_caps_msg {
struct input_proxy_device_caps caps;
/* from this point, structure may be truncated after any field (and
* input_proxy_hello.caps_size set smaller accordingly); default value of 0
* is assumed then */
char name[128];
struct input_absinfo absinfo[ABS_CNT];
};

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