Use linux /dev/input for global hotkeys instead of x11. This also works on wayland on any compositor

src/GlobalHotkeysLinux.cpp

@@ -0,0 +1,108 @@
+#include "../include/GlobalHotkeysLinux.hpp"
+#include <signal.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <string.h>
+
+#define PIPE_READ 0
+#define PIPE_WRITE 1
+
+namespace gsr {
+    GlobalHotkeysLinux::GlobalHotkeysLinux() {
+        for(int i = 0; i < 2; ++i) {
+            pipes[i] = -1;
+        }
+    }
+
+    GlobalHotkeysLinux::~GlobalHotkeysLinux() {
+        for(int i = 0; i < 2; ++i) {
+            if(pipes[i] > 0)
+                close(pipes[i]);
+        }
+
+        if(read_file)
+            fclose(read_file);
+
+        if(process_id > 0) {
+            kill(process_id, SIGKILL);
+            int status;
+            waitpid(process_id, &status, 0);
+        }
+    }
+
+    bool GlobalHotkeysLinux::start() {
+        if(process_id > 0)
+            return false;
+
+        if(pipe(pipes) == -1)
+            return false;
+
+        const pid_t pid = vfork();
+        if(pid == -1) {
+            perror("Failed to vfork");
+            for(int i = 0; i < 2; ++i) {
+                close(pipes[i]);
+                pipes[i] = -1;
+            }
+            return false;
+        } else if(pid == 0) { /* child */
+            dup2(pipes[PIPE_WRITE], STDOUT_FILENO);
+            for(int i = 0; i < 2; ++i) {
+                close(pipes[i]);
+            }
+
+            const char *args[] = { "gsr-global-hotkeys", NULL };
+            execvp(args[0], (char* const*)args);
+            perror("execvp");
+            _exit(127);
+        } else { /* parent */
+            process_id = pid;
+            close(pipes[PIPE_WRITE]);
+            pipes[PIPE_WRITE] = -1;
+
+            const int fdl = fcntl(pipes[PIPE_READ], F_GETFL);
+            fcntl(pipes[PIPE_READ], F_SETFL, fdl | O_NONBLOCK);
+
+            read_file = fdopen(pipes[PIPE_READ], "r");
+            if(read_file)
+                pipes[PIPE_READ] = -1;
+            else
+                fprintf(stderr, "fdopen failed, error: %s\n", strerror(errno));
+        }
+
+        return true;
+    }
+
+    bool GlobalHotkeysLinux::bind_action(const std::string &id, GlobalHotkeyCallback callback) {
+        return bound_actions_by_id.insert(std::make_pair(id, callback)).second;
+    }
+
+    void GlobalHotkeysLinux::poll_events() {
+        if(process_id <= 0) {
+            fprintf(stderr, "error: GlobalHotkeysLinux::poll_events failed, process has not been started yet. Use GlobalHotkeysLinux::start to start the process first\n");
+            return;
+        }
+
+        if(!read_file) {
+            fprintf(stderr, "error: GlobalHotkeysLinux::poll_events failed, read file hasn't opened\n");
+            return;
+        }
+
+        char buffer[256];
+        char *line = fgets(buffer, sizeof(buffer), read_file);
+        if(!line)
+            return;
+
+        const int line_len = strlen(line);
+        if(line_len == 0)
+            return;
+
+        if(line[line_len - 1] == '\n')
+            line[line_len - 1] = '\0';
+
+        const std::string action = line;
+        auto it = bound_actions_by_id.find(action);
+        if(it != bound_actions_by_id.end())
+            it->second(action);
+    }
+}