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badvpn/ncd/modules/sys_evdev.c

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/**
* @file sys_evdev.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Linux event device module.
*
* Synopsis: sys.evdev(string device)
* Description: reports input events from a Linux event device. Transitions up when an event is
* detected, and goes down waiting for the next event when sys.evdev::nextevent() is called.
* Variables:
* string type - symbolic event type (e.g. EV_KEY, EV_REL, EV_ABS), corresponding to
* (struct input_event).type, or "unknown"
* string value - event value (signed integer), equal to (struct input_event).value
* string code_numeric - numeric event code (unsigned integer), equal to
* (struct input_event).code
* string code - symbolic event code (e.g. KEY_ESC. KEY_1, KEY_2, BTN_LEFT), corrresponding
* to (struct input_event).code, or "unknown"
*
* Synopsis: sys.evdev::nextevent()
* Description: makes the evdev module transition down in order to report the next event.
*/
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/input.h>
#include <misc/nonblocking.h>
#include <misc/debug.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_sys_evdev.h>
#include "linux_input_names.h"
struct instance {
NCDModuleInst *i;
int evdev_fd;
BFileDescriptor bfd;
int processing;
struct input_event event;
};
static void instance_free (struct instance *o, int is_error);
enum {STRING_VALUE, STRING_CODE_NUMERIC, STRING_CODE};
static const char *strings[] = {
"value", "code_numeric", "code", NULL
};
#define MAKE_LOOKUP_FUNC(_name_) \
static const char * evdev_##_name_##_to_str (uint16_t type) \
{ \
if (type >= (sizeof(_name_##_names) / sizeof(_name_##_names[0])) || !_name_##_names[type]) { \
return "unknown"; \
} \
return _name_##_names[type]; \
}
MAKE_LOOKUP_FUNC(type)
MAKE_LOOKUP_FUNC(syn)
MAKE_LOOKUP_FUNC(key)
MAKE_LOOKUP_FUNC(rel)
MAKE_LOOKUP_FUNC(abs)
MAKE_LOOKUP_FUNC(sw)
MAKE_LOOKUP_FUNC(msc)
MAKE_LOOKUP_FUNC(led)
MAKE_LOOKUP_FUNC(rep)
MAKE_LOOKUP_FUNC(snd)
MAKE_LOOKUP_FUNC(ffstatus)
static void device_handler (struct instance *o, int events)
{
if (o->processing) {
ModuleLog(o->i, BLOG_ERROR, "device error");
instance_free(o, 1);
return;
}
int res = read(o->evdev_fd, &o->event, sizeof(o->event));
if (res < 0) {
ModuleLog(o->i, BLOG_ERROR, "read failed");
instance_free(o, 1);
return;
}
if (res != sizeof(o->event)) {
ModuleLog(o->i, BLOG_ERROR, "read wrong");
instance_free(o, 1);
return;
}
// stop reading
BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, 0);
// set processing
o->processing = 1;
// signal up
NCDModuleInst_Backend_Up(o->i);
}
static void device_nextevent (struct instance *o)
{
ASSERT(o->processing)
// start reading
BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, BREACTOR_READ);
// set not processing
o->processing = 0;
// signal down
NCDModuleInst_Backend_Down(o->i);
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct instance *o = vo;
o->i = i;
// check arguments
NCDValRef device_arg;
if (!NCDVal_ListRead(params->args, 1, &device_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsStringNoNulls(device_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
// null terminate device
NCDValNullTermString device_nts;
if (!NCDVal_StringNullTerminate(device_arg, &device_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail0;
}
// open device
o->evdev_fd = open(device_nts.data, O_RDONLY);
NCDValNullTermString_Free(&device_nts);
if (o->evdev_fd < 0) {
ModuleLog(o->i, BLOG_ERROR, "open failed");
goto fail0;
}
// set non-blocking
if (!badvpn_set_nonblocking(o->evdev_fd)) {
ModuleLog(o->i, BLOG_ERROR, "badvpn_set_nonblocking failed");
goto fail1;
}
// init BFileDescriptor
BFileDescriptor_Init(&o->bfd, o->evdev_fd, (BFileDescriptor_handler)device_handler, o);
if (!BReactor_AddFileDescriptor(o->i->params->iparams->reactor, &o->bfd)) {
ModuleLog(o->i, BLOG_ERROR, "BReactor_AddFileDescriptor failed");
goto fail1;
}
BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, BREACTOR_READ);
// set not processing
o->processing = 0;
return;
fail1:
if (close(o->evdev_fd) < 0) {
ModuleLog(o->i, BLOG_ERROR, "close failed");
}
fail0:
NCDModuleInst_Backend_DeadError(i);
}
void instance_free (struct instance *o, int is_error)
{
// free BFileDescriptor
BReactor_RemoveFileDescriptor(o->i->params->iparams->reactor, &o->bfd);
// close device.
// Ignore close error which happens if the device is removed.
if (close(o->evdev_fd) < 0) {
ModuleLog(o->i, BLOG_ERROR, "close failed");
}
if (is_error) {
NCDModuleInst_Backend_DeadError(o->i);
} else {
NCDModuleInst_Backend_Dead(o->i);
}
}
static void func_die (void *vo)
{
struct instance *o = vo;
instance_free(o, 0);
}
static int func_getvar2 (void *vo, NCD_string_id_t name, NCDValMem *mem, NCDValRef *out)
{
struct instance *o = vo;
ASSERT(o->processing)
if (name == NCD_STRING_TYPE) {
*out = NCDVal_NewString(mem, evdev_type_to_str(o->event.type));
return 1;
}
if (name == ModuleString(o->i, STRING_VALUE)) {
char str[50];
snprintf(str, sizeof(str), "%"PRIi32, o->event.value);
*out = NCDVal_NewString(mem, str);
return 1;
}
if (name == ModuleString(o->i, STRING_CODE_NUMERIC)) {
*out = ncd_make_uintmax(mem, o->event.code);
return 1;
}
if (name == ModuleString(o->i, STRING_CODE)) {
const char *str = "unknown";
#define MAKE_CASE(_evname_, _name_) \
case _evname_: \
str = evdev_##_name_##_to_str(o->event.code); \
break;
switch (o->event.type) {
#ifdef EV_KEY
MAKE_CASE(EV_KEY, key)
#endif
#ifdef EV_SYN
MAKE_CASE(EV_SYN, syn)
#endif
#ifdef EV_REL
MAKE_CASE(EV_REL, rel)
#endif
#ifdef EV_ABS
MAKE_CASE(EV_ABS, abs)
#endif
#ifdef EV_SW
MAKE_CASE(EV_SW, sw)
#endif
#ifdef EV_MSC
MAKE_CASE(EV_MSC, msc)
#endif
#ifdef EV_LED
MAKE_CASE(EV_LED, led)
#endif
#ifdef EV_REP
MAKE_CASE(EV_REP, rep)
#endif
#ifdef EV_SND
MAKE_CASE(EV_SND, snd)
#endif
#ifdef EV_FF_STATUS
MAKE_CASE(EV_FF_STATUS, ffstatus)
#endif
}
*out = NCDVal_NewString(mem, str);
return 1;
}
return 0;
}
static void nextevent_func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
// check arguments
if (!NCDVal_ListRead(params->args, 0)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
// get method object
struct instance *mo = NCDModuleInst_Backend_GetUser((NCDModuleInst *)params->method_user);
// make sure we are currently reporting an event
if (!mo->processing) {
ModuleLog(i, BLOG_ERROR, "not reporting an event");
goto fail0;
}
// signal up.
// Do it before finishing the event so our process does not advance any further if
// we would be killed the event provider going down.
NCDModuleInst_Backend_Up(i);
// wait for next event
device_nextevent(mo);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static struct NCDModule modules[] = {
{
.type = "sys.evdev",
.func_new2 = func_new,
.func_die = func_die,
.func_getvar2 = func_getvar2,
.alloc_size = sizeof(struct instance)
}, {
.type = "sys.evdev::nextevent",
.func_new2 = nextevent_func_new
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_sys_evdev = {
.modules = modules,
.strings = strings
};
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