From 9c89e52692e1033b82e201350d4d2935b3bf4598 Mon Sep 17 00:00:00 2001 From: Alessandro Mauri Date: Wed, 13 May 2020 00:22:16 +0200 Subject: [PATCH] update on device change with inotify --- hkd.c | 107 ++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 66 insertions(+), 41 deletions(-) diff --git a/hkd.c b/hkd.c index 694ddee..9e3470d 100644 --- a/hkd.c +++ b/hkd.c @@ -7,11 +7,11 @@ #include #include #include -#include #include #include #include #include +#include #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< 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; +}