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update on device change with inotify

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xkbcommon
Alessandro Mauri 4 years ago
parent 4042c02ada
commit 9c89e52692
1 changed files with 66 additions and 41 deletions
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  1. 107
      hkd.c

107
hkd.c
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@ -7,11 +7,11 @@
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <poll.h>
#include <signal.h>
#include <sys/wait.h>
#include <linux/input.h>
#include <sys/epoll.h>
#include <sys/inotify.h>
#define ANSI_COLOR_RED "\x1b[31m"
#define ANSI_COLOR_GREEN "\x1b[32m"
@ -26,12 +26,15 @@
#define test_bit(yalv, abs_b) ((((char *)abs_b)[yalv/8] & (1<<yalv%8)) > 0)
#define die(str) {perror(red(str)); exit(errno);}
#define EVENT_SIZE (sizeof(struct inotify_event))
#define EVENT_BUF_LEN (1024 * ( EVENT_SIZE + 16 ))
struct key_buffer {
unsigned short *buf;
unsigned int size;
};
int term = 0; // exit flag
int dead = 0; // exit flag
const char evdev_root_dir[] = "/dev/input/";
int key_buffer_add (struct key_buffer*, unsigned short);
@ -39,68 +42,70 @@ int key_buffer_remove (struct key_buffer*, unsigned short);
int convert_key_value (unsigned short);
void int_handler (int signum);
void exec_command(char *);
void update_descriptors_list (struct pollfd **, int *);
void update_descriptors_list (int **, int *);
int prepare_epoll(int *, int, int);
// TODO: use getopts() to parse command line options
int main (void)
{
/* Handle SIGINT */
term = 0;
dead = 0;
struct sigaction action;
memset(&action, 0, sizeof(action));
action.sa_handler = int_handler;
sigaction(SIGINT, &action, NULL);
int fd_num = 0;
struct pollfd *fds = NULL;
int *fds = NULL;
update_descriptors_list(&fds, &fd_num);
if (fd_num) {
fprintf(stderr, yellow("Monitoring %d devices\n"), fd_num);
} else {
fprintf(stderr, red("Could not open any devices, exiting\n"));
exit(-1);
}
// TODO: watch for events inside /dev/input and reload accordingly
// could use the epoll syscall or the inotify API (linux),
// event API (openbsd), kqueue syscall (BSD and macos), a separate
// process or some polling system inside the main loop to maintain
// portability across other *NIX derivatives, could also use libev
int event_watcher = inotify_init1(IN_NONBLOCK);
if (event_watcher < 0)
die("could not call inotify_init");
if (inotify_add_watch(event_watcher, evdev_root_dir, IN_CREATE | IN_DELETE) < 0)
die("could not add /dev/input to the watch list");
struct input_event event;
struct key_buffer pb = {NULL, 0}; // Pressed keys buffer
ssize_t rb; // Read bits
/* Prepare for epoll */
fprintf(stderr, yellow("using epoll based polling\n"));
struct epoll_event epoll_read_ev;
epoll_read_ev.events = EPOLLIN;
int ev_fd = epoll_create(1);
if (ev_fd < 0)
die("epoll_create");
for (int i = 0; i < fd_num; i++)
if (epoll_ctl(ev_fd, EPOLL_CTL_ADD, fds[i].fd, &epoll_read_ev) < 0)
die("epoll_ctl");
/* Prepare for epoll */
int ev_fd;
ev_fd = prepare_epoll(fds, fd_num, event_watcher);
/* MAIN EVENT LOOP */
mainloop_begin:
for (;;) {
// TODO: better error reporting
/* On linux use epoll(2) as it gives better performance */
static struct epoll_event ev_type;
if (epoll_wait(ev_fd, &ev_type, fd_num, -1) == -1 || term)
if (epoll_wait(ev_fd, &ev_type, fd_num, -1) < 0 || dead)
break;
char buf[EVENT_BUF_LEN];
if (read(event_watcher, buf, EVENT_BUF_LEN) >= 0) {
sleep(1); // wait for devices to settle
update_descriptors_list(&fds, &fd_num);
if (close(ev_fd) < 0)
die("could not close event filedescriptors list (ev_fd)");
ev_fd = prepare_epoll(fds, fd_num, event_watcher);
goto mainloop_begin;
}
static int i;
static unsigned int prev_size;
prev_size = pb.size;
for (i = 0; i < fd_num; i++) {
if (ev_type.events == EPOLLIN) {
for (i = 0; i < fd_num; i++) {
if (ev_type.events == EPOLLIN) {
rb = read(fds[i].fd, &event, sizeof(struct input_event));
rb = read(fds[i], &event, sizeof(struct input_event));
if (rb != sizeof(struct input_event)) continue;
/* Ignore touchpad events */
@ -151,12 +156,12 @@ for (int i = 0; i < fd_num; i++)
// interrupts as the father so everything should work fine for now
wait(NULL);
free(pb.buf);
if (!term)
fprintf(stderr, red("An error occured\n"));
for (int i = 0; i < fd_num; i++) {
if (close(fds[i].fd) == -1)
if (!dead)
fprintf(stderr, red("an error occured\n"));
close(event_watcher);
for (int i = 0; i < fd_num; i++)
if (close(fds[i]) == -1)
die("close file descriptors");
}
return 0;
}
@ -208,7 +213,7 @@ int key_buffer_remove (struct key_buffer *pb, unsigned short key)
void int_handler (int signum)
{
fprintf(stderr, yellow("Received interrupt signal, exiting gracefully...\n"));
term = 1;
dead = 1;
}
void exec_command (char *path)
@ -232,7 +237,7 @@ void exec_command (char *path)
// TODO: communication between parent and child about process status/errors/etc
}
void update_descriptors_list (struct pollfd **fds, int *fd_num)
void update_descriptors_list (int **fds, int *fd_num)
{
struct dirent *file_ent;
char ev_path[sizeof(evdev_root_dir) + NAME_MAX + 1];
@ -242,11 +247,11 @@ void update_descriptors_list (struct pollfd **fds, int *fd_num)
/* Open the event directory */
DIR *ev_dir = opendir(evdev_root_dir);
if (!ev_dir)
die("opendir");
die("Could not open /dev/input");
(*fd_num) = 0;
if ((*fds))
free(fds);
free(*fds);
for (;;) {
@ -280,16 +285,21 @@ void update_descriptors_list (struct pollfd **fds, int *fd_num)
continue;
}
tmp_p = realloc((*fds), sizeof(struct pollfd) * ((*fd_num) + 1));
tmp_p = realloc((*fds), sizeof(int) * ((*fd_num) + 1));
if (!tmp_p)
die("realloc file descriptors");
(*fds) = (struct pollfd *) tmp_p;
(*fds) = (int *) tmp_p;
(*fds)[(*fd_num)].events = POLLIN;
(*fds)[(*fd_num)].fd = tmp_fd;
(*fds)[(*fd_num)] = tmp_fd;
(*fd_num)++;
}
closedir(ev_dir);
if (*fd_num) {
fprintf(stderr, yellow("Monitoring %d devices\n"), *fd_num);
} else {
fprintf(stderr, red("Could not open any devices, exiting\n"));
exit(-1);
}
}
int convert_key_value (unsigned short key)
@ -297,3 +307,18 @@ int convert_key_value (unsigned short key)
int outchar = 0;
return outchar;
}
int prepare_epoll(int *fds, int fd_num, int event_watcher)
{
static struct epoll_event epoll_read_ev;
epoll_read_ev.events = EPOLLIN;
int ev_fd = epoll_create(1);
if (ev_fd < 0)
die("failed epoll_create");
if (epoll_ctl(ev_fd, EPOLL_CTL_ADD, event_watcher, &epoll_read_ev) < 0)
die("could not add file descriptor to the epoll list");
for (int i = 0; i < fd_num; i++)
if (epoll_ctl(ev_fd, EPOLL_CTL_ADD, fds[i], &epoll_read_ev) < 0)
die("could not add file descriptor to the epoll list");
return ev_fd;
}

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