1 files changed, 376 insertions, 0 deletions

diff --git a/externals/gamemode/gamemode_client.h b/externals/gamemode/gamemode_client.h
new file mode 100644
index 000000000..b9f64fe46
--- /dev/null
+++ b/externals/gamemode/gamemode_client.h
@@ -0,0 +1,376 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * 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.
+ * Neither the name of Feral Interactive 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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
+
+ */
+#ifndef CLIENT_GAMEMODE_H
+#define CLIENT_GAMEMODE_H
+/*
+ * GameMode supports the following client functions
+ * Requests are refcounted in the daemon
+ *
+ * int gamemode_request_start() - Request gamemode starts
+ *   0 if the request was sent successfully
+ *   -1 if the request failed
+ *
+ * int gamemode_request_end() - Request gamemode ends
+ *   0 if the request was sent successfully
+ *   -1 if the request failed
+ *
+ * GAMEMODE_AUTO can be defined to make the above two functions apply during static init and
+ * destruction, as appropriate. In this configuration, errors will be printed to stderr
+ *
+ * int gamemode_query_status() - Query the current status of gamemode
+ *   0 if gamemode is inactive
+ *   1 if gamemode is active
+ *   2 if gamemode is active and this client is registered
+ *   -1 if the query failed
+ *
+ * int gamemode_request_start_for(pid_t pid) - Request gamemode starts for another process
+ *   0 if the request was sent successfully
+ *   -1 if the request failed
+ *   -2 if the request was rejected
+ *
+ * int gamemode_request_end_for(pid_t pid) - Request gamemode ends for another process
+ *   0 if the request was sent successfully
+ *   -1 if the request failed
+ *   -2 if the request was rejected
+ *
+ * int gamemode_query_status_for(pid_t pid) - Query status of gamemode for another process
+ *   0 if gamemode is inactive
+ *   1 if gamemode is active
+ *   2 if gamemode is active and this client is registered
+ *   -1 if the query failed
+ *
+ * const char* gamemode_error_string() - Get an error string
+ *   returns a string describing any of the above errors
+ *
+ * Note: All the above requests can be blocking - dbus requests can and will block while the daemon
+ * handles the request. It is not recommended to make these calls in performance critical code
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <dlfcn.h>
+#include <string.h>
+
+#include <assert.h>
+
+#include <sys/types.h>
+
+static char internal_gamemode_client_error_string[512] = { 0 };
+
+/**
+ * Load libgamemode dynamically to dislodge us from most dependencies.
+ * This allows clients to link and/or use this regardless of runtime.
+ * See SDL2 for an example of the reasoning behind this in terms of
+ * dynamic versioning as well.
+ */
+static volatile int internal_libgamemode_loaded = 1;
+
+/* Typedefs for the functions to load */
+typedef int (*api_call_return_int)(void);
+typedef const char *(*api_call_return_cstring)(void);
+typedef int (*api_call_pid_return_int)(pid_t);
+
+/* Storage for functors */
+static api_call_return_int REAL_internal_gamemode_request_start = NULL;
+static api_call_return_int REAL_internal_gamemode_request_end = NULL;
+static api_call_return_int REAL_internal_gamemode_query_status = NULL;
+static api_call_return_cstring REAL_internal_gamemode_error_string = NULL;
+static api_call_pid_return_int REAL_internal_gamemode_request_start_for = NULL;
+static api_call_pid_return_int REAL_internal_gamemode_request_end_for = NULL;
+static api_call_pid_return_int REAL_internal_gamemode_query_status_for = NULL;
+
+/**
+ * Internal helper to perform the symbol binding safely.
+ *
+ * Returns 0 on success and -1 on failure
+ */
+__attribute__((always_inline)) static inline int internal_bind_libgamemode_symbol(
+    void *handle, const char *name, void **out_func, size_t func_size, bool required)
+{
+        void *symbol_lookup = NULL;
+        char *dl_error = NULL;
+
+        /* Safely look up the symbol */
+        symbol_lookup = dlsym(handle, name);
+        dl_error = dlerror();
+        if (required && (dl_error || !symbol_lookup)) {
+                snprintf(internal_gamemode_client_error_string,
+                         sizeof(internal_gamemode_client_error_string),
+                         "dlsym failed - %s",
+                         dl_error);
+                return -1;
+        }
+
+        /* Have the symbol correctly, copy it to make it usable */
+        memcpy(out_func, &symbol_lookup, func_size);
+        return 0;
+}
+
+/**
+ * Loads libgamemode and needed functions
+ *
+ * Returns 0 on success and -1 on failure
+ */
+__attribute__((always_inline)) static inline int internal_load_libgamemode(void)
+{
+        /* We start at 1, 0 is a success and -1 is a fail */
+        if (internal_libgamemode_loaded != 1) {
+                return internal_libgamemode_loaded;
+        }
+
+        /* Anonymous struct type to define our bindings */
+        struct binding {
+                const char *name;
+                void **functor;
+                size_t func_size;
+                bool required;
+        } bindings[] = {
+                { "real_gamemode_request_start",
+                  (void **)&REAL_internal_gamemode_request_start,
+                  sizeof(REAL_internal_gamemode_request_start),
+                  true },
+                { "real_gamemode_request_end",
+                  (void **)&REAL_internal_gamemode_request_end,
+                  sizeof(REAL_internal_gamemode_request_end),
+                  true },
+                { "real_gamemode_query_status",
+                  (void **)&REAL_internal_gamemode_query_status,
+                  sizeof(REAL_internal_gamemode_query_status),
+                  false },
+                { "real_gamemode_error_string",
+                  (void **)&REAL_internal_gamemode_error_string,
+                  sizeof(REAL_internal_gamemode_error_string),
+                  true },
+                { "real_gamemode_request_start_for",
+                  (void **)&REAL_internal_gamemode_request_start_for,
+                  sizeof(REAL_internal_gamemode_request_start_for),
+                  false },
+                { "real_gamemode_request_end_for",
+                  (void **)&REAL_internal_gamemode_request_end_for,
+                  sizeof(REAL_internal_gamemode_request_end_for),
+                  false },
+                { "real_gamemode_query_status_for",
+                  (void **)&REAL_internal_gamemode_query_status_for,
+                  sizeof(REAL_internal_gamemode_query_status_for),
+                  false },
+        };
+
+        void *libgamemode = NULL;
+
+        /* Try and load libgamemode */
+        libgamemode = dlopen("libgamemode.so.0", RTLD_NOW);
+        if (!libgamemode) {
+                /* Attempt to load unversioned library for compatibility with older
+                 * versions (as of writing, there are no ABI changes between the two -
+                 * this may need to change if ever ABI-breaking changes are made) */
+                libgamemode = dlopen("libgamemode.so", RTLD_NOW);
+                if (!libgamemode) {
+                        snprintf(internal_gamemode_client_error_string,
+                                 sizeof(internal_gamemode_client_error_string),
+                                 "dlopen failed - %s",
+                                 dlerror());
+                        internal_libgamemode_loaded = -1;
+                        return -1;
+                }
+        }
+
+        /* Attempt to bind all symbols */
+        for (size_t i = 0; i < sizeof(bindings) / sizeof(bindings[0]); i++) {
+                struct binding *binder = &bindings[i];
+
+                if (internal_bind_libgamemode_symbol(libgamemode,
+                                                     binder->name,
+                                                     binder->functor,
+                                                     binder->func_size,
+                                                     binder->required)) {
+                        internal_libgamemode_loaded = -1;
+                        return -1;
+                };
+        }
+
+        /* Success */
+        internal_libgamemode_loaded = 0;
+        return 0;
+}
+
+/**
+ * Redirect to the real libgamemode
+ */
+__attribute__((always_inline)) static inline const char *gamemode_error_string(void)
+{
+        /* If we fail to load the system gamemode, or we have an error string already, return our error
+         * string instead of diverting to the system version */
+        if (internal_load_libgamemode() < 0 || internal_gamemode_client_error_string[0] != '\0') {
+                return internal_gamemode_client_error_string;
+        }
+
+        /* Assert for static analyser that the function is not NULL */
+        assert(REAL_internal_gamemode_error_string != NULL);
+
+        return REAL_internal_gamemode_error_string();
+}
+
+/**
+ * Redirect to the real libgamemode
+ * Allow automatically requesting game mode
+ * Also prints errors as they happen.
+ */
+#ifdef GAMEMODE_AUTO
+__attribute__((constructor))
+#else
+__attribute__((always_inline)) static inline
+#endif
+int gamemode_request_start(void)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+#ifdef GAMEMODE_AUTO
+                fprintf(stderr, "gamemodeauto: %s\n", gamemode_error_string());
+#endif
+                return -1;
+        }
+
+        /* Assert for static analyser that the function is not NULL */
+        assert(REAL_internal_gamemode_request_start != NULL);
+
+        if (REAL_internal_gamemode_request_start() < 0) {
+#ifdef GAMEMODE_AUTO
+                fprintf(stderr, "gamemodeauto: %s\n", gamemode_error_string());
+#endif
+                return -1;
+        }
+
+        return 0;
+}
+
+/* Redirect to the real libgamemode */
+#ifdef GAMEMODE_AUTO
+__attribute__((destructor))
+#else
+__attribute__((always_inline)) static inline
+#endif
+int gamemode_request_end(void)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+#ifdef GAMEMODE_AUTO
+                fprintf(stderr, "gamemodeauto: %s\n", gamemode_error_string());
+#endif
+                return -1;
+        }
+
+        /* Assert for static analyser that the function is not NULL */
+        assert(REAL_internal_gamemode_request_end != NULL);
+
+        if (REAL_internal_gamemode_request_end() < 0) {
+#ifdef GAMEMODE_AUTO
+                fprintf(stderr, "gamemodeauto: %s\n", gamemode_error_string());
+#endif
+                return -1;
+        }
+
+        return 0;
+}
+
+/* Redirect to the real libgamemode */
+__attribute__((always_inline)) static inline int gamemode_query_status(void)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+                return -1;
+        }
+
+        if (REAL_internal_gamemode_query_status == NULL) {
+                snprintf(internal_gamemode_client_error_string,
+                         sizeof(internal_gamemode_client_error_string),
+                         "gamemode_query_status missing (older host?)");
+                return -1;
+        }
+
+        return REAL_internal_gamemode_query_status();
+}
+
+/* Redirect to the real libgamemode */
+__attribute__((always_inline)) static inline int gamemode_request_start_for(pid_t pid)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+                return -1;
+        }
+
+        if (REAL_internal_gamemode_request_start_for == NULL) {
+                snprintf(internal_gamemode_client_error_string,
+                         sizeof(internal_gamemode_client_error_string),
+                         "gamemode_request_start_for missing (older host?)");
+                return -1;
+        }
+
+        return REAL_internal_gamemode_request_start_for(pid);
+}
+
+/* Redirect to the real libgamemode */
+__attribute__((always_inline)) static inline int gamemode_request_end_for(pid_t pid)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+                return -1;
+        }
+
+        if (REAL_internal_gamemode_request_end_for == NULL) {
+                snprintf(internal_gamemode_client_error_string,
+                         sizeof(internal_gamemode_client_error_string),
+                         "gamemode_request_end_for missing (older host?)");
+                return -1;
+        }
+
+        return REAL_internal_gamemode_request_end_for(pid);
+}
+
+/* Redirect to the real libgamemode */
+__attribute__((always_inline)) static inline int gamemode_query_status_for(pid_t pid)
+{
+        /* Need to load gamemode */
+        if (internal_load_libgamemode() < 0) {
+                return -1;
+        }
+
+        if (REAL_internal_gamemode_query_status_for == NULL) {
+                snprintf(internal_gamemode_client_error_string,
+                         sizeof(internal_gamemode_client_error_string),
+                         "gamemode_query_status_for missing (older host?)");
+                return -1;
+        }
+
+        return REAL_internal_gamemode_query_status_for(pid);
+}
+
+#endif // CLIENT_GAMEMODE_H