Merge pull request #173 from gicmo/pidfds

Introduce a new pidfd based set of D-Bus APIs
This commit is contained in:
Alex Smith 2019-10-22 12:31:00 +01:00 committed by GitHub
commit 514ab58be3
11 changed files with 567 additions and 46 deletions

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@ -39,3 +39,4 @@ POSSIBILITY OF SUCH DAMAGE.
* a specific call to the function the linker will expect an definition.
*/
extern inline void cleanup_close(int *fd);
extern inline void cleanup_free(void *ptr);

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@ -31,6 +31,7 @@ POSSIBILITY OF SUCH DAMAGE.
#pragma once
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <unistd.h>
@ -80,3 +81,23 @@ inline void cleanup_close(int *fd_ptr)
* like "autoclose_fd int fd = -1;".
*/
#define autoclose_fd __attribute__((cleanup(cleanup_close)))
/**
* Helper function for auto-freeing dynamically allocated memory. Does nothing
* if *ptr is NULL (ptr must not be NULL).
*/
inline void cleanup_free(void *ptr)
{
/* The function is defined to work with 'void *' because
* that will make sure it compiles without warning also
* for all types; what we are getting passed into is a
* pointer to a pointer though, so we need to cast */
void *target = *(void **)ptr;
free(target); /* free can deal with NULL */
}
/**
* Helper macro for auto-freeing dynamically allocated memory: use by
* prefixing the variable, like "autofree char *data = NULL;".
*/
#define autofree __attribute__((cleanup(cleanup_free)))

207
common/common-pidfds.c Normal file
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@ -0,0 +1,207 @@
/*
Copyright (c) 2017-2019, Feral Interactive
Copyright (c) 2019, Red Hat
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.
*/
#define _GNU_SOURCE
#include <build-config.h>
#include "common-helpers.h"
#include "common-pidfds.h"
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#if !HAVE_FN_PIDFD_OPEN
#include <sys/syscall.h>
#ifndef __NR_pidfd_open
#define __NR_pidfd_open 434
#endif
static int pidfd_open(pid_t pid, unsigned int flags)
{
return (int)syscall(__NR_pidfd_open, pid, flags);
}
#endif
/* pidfd functions */
int open_pidfds(pid_t *pids, int *fds, int count)
{
int i = 0;
for (i = 0; i < count; i++) {
int pid = pids[i];
int fd = pidfd_open(pid, 0);
if (fd < 0)
break;
fds[i] = fd;
}
return i;
}
static int parse_pid(const char *str, pid_t *pid)
{
unsigned long long int v;
char *end;
pid_t p;
errno = 0;
v = strtoull(str, &end, 0);
if (end == str)
return -ENOENT;
else if (errno != 0)
return -errno;
p = (pid_t)v;
if (p < 1 || (unsigned long long int)p != v)
return -ERANGE;
if (pid)
*pid = p;
return 0;
}
static int parse_status_field_pid(const char *val, pid_t *pid)
{
const char *t;
t = strrchr(val, '\t');
if (t == NULL)
return -ENOENT;
return parse_pid(t, pid);
}
static int pidfd_to_pid(int fdinfo, int pidfd, pid_t *pid)
{
autofree char *key = NULL;
autofree char *val = NULL;
char name[256] = {
0,
};
bool found = false;
FILE *f = NULL;
size_t keylen = 0;
size_t vallen = 0;
ssize_t n;
int fd;
int r = 0;
*pid = 0;
buffered_snprintf(name, "%d", pidfd);
fd = openat(fdinfo, name, O_RDONLY | O_CLOEXEC | O_NOCTTY);
if (fd != -1)
f = fdopen(fd, "r");
if (f == NULL)
return -errno;
do {
n = getdelim(&key, &keylen, ':', f);
if (n == -1) {
r = errno;
break;
}
n = getdelim(&val, &vallen, '\n', f);
if (n == -1) {
r = errno;
break;
}
// TODO: strstrip (key);
if (!strncmp(key, "Pid", 3)) {
r = parse_status_field_pid(val, pid);
found = r > -1;
}
} while (r == 0 && !found);
fclose(f);
if (r < 0)
return r;
else if (!found)
return -ENOENT;
return 0;
}
int pidfds_to_pids(int *fds, pid_t *pids, int count)
{
int fdinfo = -1;
int r = 0;
int i;
fdinfo = open_fdinfo_dir();
if (fdinfo == -1)
return -1;
for (i = 0; i < count && r == 0; i++)
r = pidfd_to_pid(fdinfo, fds[i], &pids[i]);
(void)close(fdinfo);
if (r != 0)
errno = -r;
return i;
}
/* misc directory helpers */
int open_fdinfo_dir(void)
{
int fd;
fd = open("/proc/self/fdinfo", O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC | O_NOCTTY);
if (fd == -1)
return errno;
return fd;
}

53
common/common-pidfds.h Normal file
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@ -0,0 +1,53 @@
/*
Copyright (c) 2017-2019, Feral Interactive
Copyright (c) 2019, Red Hat
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.
*/
#include <sys/types.h>
/* Open pidfds for up to count process ids specified in pids. The
* pointer fds needs to point to an array with at least count
* entries. Will stop when it encounters an error (and sets errno).
* Returns the number of successfully opened pidfds (or -1 in case
* of other errors. */
int open_pidfds(pid_t *pids, int *fds, int count);
/* Translate up to count process ids to the corresponding process ids.
* The pointer pids needs to point to an array with at least count
* entries. Will stop when it encounters an error (and sets errno).
* Returns the number of successfully translated pidfds (or -1 in
* case of other errors. */
int pidfds_to_pids(int *fds, pid_t *pids, int count);
/* Helper to open the fdinfo directory for the current process, i.e.
* does open("/proc/self/fdinfo", ...). Returns the file descriptor
* for the directory, ownership is transferred and caller needs to
* call close on it. */
int open_fdinfo_dir(void);

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@ -5,16 +5,32 @@ common_sources = [
'common-external.c',
'common-helpers.c',
'common-gpu.c',
'common-pidfds.c',
]
daemon_common = static_library(
'daemon-common',
sources: common_sources,
install: false,
include_directories: [config_h_dir]
)
link_daemon_common = declare_dependency(
link_with: daemon_common,
include_directories: [include_directories('.')]
)
include_daemon_common = include_directories('.')
lib_common = static_library(
'lib-common',
sources: [
'common-helpers.c',
'common-pidfds.c'
],
install: false,
include_directories: [config_h_dir]
)
link_lib_common = declare_dependency(
link_with: lib_common,
include_directories: [include_directories('.')]
)

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@ -32,7 +32,9 @@ POSSIBILITY OF SUCH DAMAGE.
#define _GNU_SOURCE
#include "gamemode.h"
#include "common-helpers.h"
#include "common-logging.h"
#include "common-pidfds.h"
#include <systemd/sd-bus.h>
#include <systemd/sd-daemon.h>
@ -169,7 +171,7 @@ static int method_unregister_game_by_pid(sd_bus_message *m, void *userdata,
}
/**
* Handles the QueryStatus D-BUS Method
* Handles the QueryStatusByPID D-BUS Method
*/
static int method_query_status_by_pid(sd_bus_message *m, void *userdata,
__attribute__((unused)) sd_bus_error *ret_error)
@ -188,8 +190,87 @@ static int method_query_status_by_pid(sd_bus_message *m, void *userdata,
return sd_bus_reply_method_return(m, "i", status);
}
/**
* Handles the Active D-BUS Method
* Handles the RegisterGameByPIDFd D-BUS Method
*/
static int method_register_game_by_pidfd(sd_bus_message *m, void *userdata,
__attribute__((unused)) sd_bus_error *ret_error)
{
int fds[2] = { -1, -1 };
pid_t pids[2] = { 0, 0 };
GameModeContext *context = userdata;
int ret = sd_bus_message_read(m, "hh", &fds[0], &fds[1]);
if (ret < 0) {
LOG_ERROR("Failed to parse input parameters: %s\n", strerror(-ret));
return ret;
}
int reply = pidfds_to_pids(fds, pids, 2);
if (reply == 2)
reply = game_mode_context_register(context, pids[0], pids[1]);
else
reply = -1;
return sd_bus_reply_method_return(m, "i", reply);
}
/**
* Handles the UnregisterGameByPIDFd D-BUS Method
*/
static int method_unregister_game_by_pidfd(sd_bus_message *m, void *userdata,
__attribute__((unused)) sd_bus_error *ret_error)
{
int fds[2] = { -1, -1 };
pid_t pids[2] = { 0, 0 };
GameModeContext *context = userdata;
int ret = sd_bus_message_read(m, "hh", &fds[0], &fds[1]);
if (ret < 0) {
LOG_ERROR("Failed to parse input parameters: %s\n", strerror(-ret));
return ret;
}
int reply = pidfds_to_pids(fds, pids, 2);
if (reply == 2)
reply = game_mode_context_unregister(context, pids[0], pids[1]);
else
reply = -1;
return sd_bus_reply_method_return(m, "i", reply);
}
/**
* Handles the QueryStatusByPIDFd D-BUS Method
*/
static int method_query_status_by_pidfd(sd_bus_message *m, void *userdata,
__attribute__((unused)) sd_bus_error *ret_error)
{
int fds[2] = { -1, -1 };
pid_t pids[2] = { 0, 0 };
GameModeContext *context = userdata;
int ret = sd_bus_message_read(m, "hh", &fds[0], &fds[1]);
if (ret < 0) {
LOG_ERROR("Failed to parse input parameters: %s\n", strerror(-ret));
return ret;
}
int reply = pidfds_to_pids(fds, pids, 2);
if (reply == 2)
reply = game_mode_context_query_status(context, pids[0], pids[1]);
else
reply = -1;
return sd_bus_reply_method_return(m, "i", reply);
}
/**
* Handles the ClientCount D-BUS Property
*/
static int property_get_client_count(sd_bus *local_bus, const char *path, const char *interface,
const char *property, sd_bus_message *reply, void *userdata,
@ -322,6 +403,12 @@ static const sd_bus_vtable gamemode_vtable[] = {
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatusByPID", "ii", "i", method_query_status_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("RegisterGameByPIDFd", "hh", "i", method_register_game_by_pidfd,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("UnregisterGameByPIDFd", "hh", "i", method_unregister_game_by_pidfd,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatusByPIDFd", "hh", "i", method_query_status_by_pidfd,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("RefreshConfig", "", "i", method_refresh_config, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("ListGames", "", "a(io)", method_list_games, SD_BUS_VTABLE_UNPRIVILEGED),

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@ -26,7 +26,6 @@ executable(
],
include_directories: [
gamemoded_includes,
include_daemon_common,
],
install: true,
)

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@ -31,8 +31,14 @@ POSSIBILITY OF SUCH DAMAGE.
#define _GNU_SOURCE
#include <common-helpers.h>
#include <common-pidfds.h>
#include <dbus/dbus.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
@ -54,6 +60,7 @@ POSSIBILITY OF SUCH DAMAGE.
#define _cleanup_bus_ _cleanup_(hop_off_the_bus)
#define _cleanup_msg_ _cleanup_(cleanup_msg)
#define _cleanup_dpc_ _cleanup_(cleanup_pending_call)
#define _cleanup_fds_ _cleanup_(cleanup_fd_array)
#ifdef NDEBUG
#define DEBUG(...)
@ -73,15 +80,49 @@ static int log_error(const char *fmt, ...) __attribute__((format(printf, 1, 2)))
// Storage for error strings
static char error_string[512] = { 0 };
// memory helpers
static void cleanup_fd_array(int **fdlist)
{
if (fdlist == NULL || *fdlist == NULL)
return;
int errsave = errno;
for (int *fd = *fdlist; *fd != -1; fd++) {
TRACE("GM Closing fd %d\n", *fd);
(void)close(*fd);
}
errno = errsave;
free(*fdlist);
}
// Allocate a -1 termianted array of ints
static inline int *alloc_fd_array(int n)
{
int *fds;
size_t count = (size_t)n + 1; /* -1, terminated */
fds = (int *)malloc(sizeof(int) * count);
for (size_t i = 0; i < count; i++)
fds[i] = -1;
return fds;
}
// Helper to check if we are running inside a flatpak
static int in_flatpak(void)
{
struct stat sb;
int r;
static int status = -1;
r = lstat("/.flatpak-info", &sb);
if (status == -1) {
struct stat sb;
int r;
return r == 0 && sb.st_size > 0;
r = lstat("/.flatpak-info", &sb);
status = r == 0 && sb.st_size > 0;
}
return status;
}
static int log_error(const char *fmt, ...)
@ -131,7 +172,7 @@ static DBusConnection *hop_on_the_bus(void)
/* cleanup functions */
static void cleanup_msg(DBusMessage **msg)
{
if (msg == NULL)
if (msg == NULL || *msg == NULL)
return;
dbus_message_unref(*msg);
@ -139,37 +180,53 @@ static void cleanup_msg(DBusMessage **msg)
static void cleanup_pending_call(DBusPendingCall **call)
{
if (call == NULL)
if (call == NULL || *call == NULL)
return;
dbus_pending_call_unref(*call);
}
/* internal API */
static int gamemode_request(const char *method, pid_t for_pid)
static int make_request(DBusConnection *bus, int native, int use_pidfds, const char *method,
pid_t *pids, int npids, DBusError *error)
{
_cleanup_bus_ DBusConnection *bus = NULL;
_cleanup_msg_ DBusMessage *msg = NULL;
_cleanup_dpc_ DBusPendingCall *call = NULL;
DBusMessageIter iter;
_cleanup_fds_ int *fds = NULL;
char action[256] = {
0,
};
DBusError err;
dbus_int32_t pid;
int native;
DBusMessageIter iter;
int res = -1;
native = !in_flatpak();
pid = (dbus_int32_t)getpid();
TRACE("GM: [%d] request '%s' received (for pid: %d) [portal: %s]\n",
(int)pid,
TRACE("GM: Incoming request: %s, npids: %d, native: %d pifds: %d\n",
method,
(int)for_pid,
(native ? "n" : "y"));
npids,
native,
use_pidfds);
bus = hop_on_the_bus();
if (use_pidfds) {
fds = alloc_fd_array(npids);
if (bus == NULL)
return -1;
res = open_pidfds(pids, fds, npids);
if (res != npids) {
dbus_set_error(error, DBUS_ERROR_FAILED, "Could not open pidfd for %d", (int)pids[res]);
return -1;
}
if (strstr(method, "ByPID"))
snprintf(action, sizeof(action), "%sFd", method);
else
snprintf(action, sizeof(action), "%sByPIDFd", method);
method = action;
}
TRACE("GM: Making request: %s, npids: %d, native: %d pifds: %d\n",
method,
npids,
native,
use_pidfds);
// If we are inside a flatpak we need to talk to the portal instead
const char *dest = native ? DAEMON_DBUS_NAME : PORTAL_DBUS_NAME;
@ -178,15 +235,25 @@ static int gamemode_request(const char *method, pid_t for_pid)
msg = dbus_message_new_method_call(dest, path, iface, method);
if (!msg)
return log_error("Could not create dbus message");
if (!msg) {
dbus_set_error_const(error, DBUS_ERROR_FAILED, "Could not create dbus message");
return -1;
}
dbus_message_iter_init_append(msg, &iter);
dbus_message_iter_append_basic(&iter, DBUS_TYPE_INT32, &pid);
if (for_pid != 0) {
dbus_int32_t p = (dbus_int32_t)for_pid;
dbus_message_iter_append_basic(&iter, DBUS_TYPE_INT32, &p);
for (int i = 0; i < npids; i++) {
dbus_int32_t p;
int type;
if (use_pidfds) {
type = DBUS_TYPE_UNIX_FD;
p = (dbus_int32_t)fds[i];
} else {
type = DBUS_TYPE_INT32;
p = (dbus_int32_t)pids[i];
}
dbus_message_iter_append_basic(&iter, type, &p);
}
dbus_connection_send_with_reply(bus, msg, &call, -1);
@ -197,20 +264,87 @@ static int gamemode_request(const char *method, pid_t for_pid)
dbus_pending_call_block(call);
msg = dbus_pending_call_steal_reply(call);
if (msg == NULL)
return log_error("Did not receive a reply");
if (msg == NULL) {
dbus_set_error_const(error, DBUS_ERROR_FAILED, "Did not receive a reply");
return -1;
}
dbus_error_init(&err);
if (dbus_set_error_from_message(&err, msg))
log_error("Could not call method '%s' on '%s': %s", method, dest, err.message);
else if (!dbus_message_iter_init(msg, &iter) ||
dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_INT32)
log_error("Failed to parse response");
else
res = -1;
if (dbus_set_error_from_message(&err, msg)) {
dbus_set_error(error,
err.name,
"Could not call method '%s' on '%s': %s",
method,
dest,
err.message);
} else if (!dbus_message_iter_init(msg, &iter) ||
dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_INT32) {
dbus_set_error(error, DBUS_ERROR_INVALID_SIGNATURE, "Failed to parse response");
} else {
dbus_message_iter_get_basic(&iter, &res);
}
TRACE("GM: [%d] request '%s' done: %d\n", (int)pid, method, res);
/* free the local error */
if (dbus_error_is_set(&err))
dbus_error_free(&err);
return res;
}
static int gamemode_request(const char *method, pid_t for_pid)
{
_cleanup_bus_ DBusConnection *bus = NULL;
static int use_pidfs = 1;
DBusError err;
pid_t pids[2];
int npids;
int native;
int res = -1;
native = !in_flatpak();
/* pid[0] is the client, i.e. the game
* pid[1] is the requestor, i.e. this process
*
* we setup the array such that pids[1] will always be a valid
* pid, because if we are going to use the pidfd based API,
* both pids are being sent, even if they are the same
*/
pids[1] = getpid();
pids[0] = for_pid != 0 ? for_pid : pids[1];
TRACE("GM: [%d] request '%s' received (by: %d) [portal: %s]\n",
(int)pids[0],
method,
(int)pids[1],
(native ? "n" : "y"));
bus = hop_on_the_bus();
if (bus == NULL)
return -1;
dbus_error_init(&err);
retry:
if (for_pid != 0 || use_pidfs)
npids = 2;
else
npids = 1;
res = make_request(bus, native, use_pidfs, method, pids, npids, &err);
if (res == -1 && use_pidfs && dbus_error_is_set(&err)) {
TRACE("GM: Request with pidfds failed (%s). Retrying.\n", err.message);
use_pidfs = 0;
dbus_error_free(&err);
goto retry;
}
if (res == -1 && dbus_error_is_set(&err))
log_error("D-Bus error: %s", err.message);
TRACE("GM: [%d] request '%s' done: %d\n", (int)pids[0], method, res);
if (dbus_error_is_set(&err))
dbus_error_free(&err);

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@ -12,6 +12,7 @@ gamemode = shared_library(
'client_impl.c',
],
dependencies: [
link_lib_common,
dep_dbus,
],
install: true,

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@ -128,21 +128,25 @@ with_examples = get_option('with-examples')
with_util = get_option('with-util')
# Provide a config.h
pidfd_open = cc.has_function('pidfd_open', args: '-D_GNU_SOURCE')
cdata = configuration_data()
cdata.set_quoted('LIBEXECDIR', path_libexecdir)
cdata.set_quoted('GAMEMODE_VERSION', meson.project_version())
cdata.set10('HAVE_FN_PIDFD_OPEN', pidfd_open)
config_h = configure_file(
configuration: cdata,
output: 'build-config.h',
)
config_h_dir = include_directories('.')
# Library is always required
subdir('lib')
# common lib is always required
subdir('common')
# Library is always required
subdir('lib')
# Utilities are always required except when having both 64 and 32 bit versions
# of libgamemode installed
if with_util == true

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@ -11,7 +11,6 @@ cpugovctl = executable(
link_daemon_common,
],
install: true,
include_directories: include_daemon_common,
install_dir: path_libexecdir,
)
@ -27,6 +26,5 @@ gpuclockctl = executable(
link_daemon_common,
],
install: true,
include_directories: include_daemon_common,
install_dir: path_libexecdir,
)