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https://github.com/FeralInteractive/gamemode.git
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68e326de60
Primarily we convert the service into a thread safe one that isn't reliant on signaling for control flow, eliminating data race conditions. We also enable interleaving by separating game mode pivoting from explicit client registration. The static pid list is now converted into a dynamic list that is OOM safe to store all registered clients (with a reasonable upper limit of 256 clients) to better handle cases where LD_PRELOAD is used for a large process group. Additionally we begin storing some metadata on the connected clients such as their executable path, which will enable us to perform some basic whitelisting in future. The cpugovctl binary is now moved into the libexecdir as an explicit helper of the D-BUS service, using the shared library to merge some code back into the daemon. This saves having to execute a process to query the state of the governors, as we don't need a privileged client to do this. In order to sanely set the governors, we require that the binary is running as euid 0, and execute this using `pkexec`. A PolKit policy definition is provided which allows active/logged in users to execute this helper through a path whitelist. As such we can convert the daemon into user-mode only, with the privileged helper being dispatched exclusively via polkit. This removes the need for a setuid helper or having a system mode daemon. Lastly we clean up the codebase a bit to be consistent with modern C code conventions, using pragmas where available. The library component still uses the older ifdef approach to support older compilers, but the daemon portion uses the directive to simplify intent and speed up compilation. Additionally we move all comments to C style comments for consistency, instead of mixing in C++ style single line comments, in order to establish a formal coding style. The net result is a more robust service which can be D-BUS activated when clients need it, that can perform scaling automatically without harassing the user with authentication popups. Signed-off-by: Ikey Doherty <ikey@solus-project.com>
107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/*
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Copyright (c) 2017, Feral Interactive
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of Feral Interactive nor the names of its contributors
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may be used to endorse or promote products derived from this software
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without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#define _GNU_SOURCE
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#include "governors.h"
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#include "config.h"
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#include "governors-query.h"
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#include "logging.h"
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#include <linux/limits.h>
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#include <stdio.h>
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#include <sys/wait.h>
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#include <unistd.h>
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static const char *initial = NULL;
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/**
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* Cache the governor state as seen at startup
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*/
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void update_initial_gov_state()
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{
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initial = get_gov_state();
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}
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/**
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* Update the governors to the given argument, via pkexec
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*/
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bool set_governors(const char *value)
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{
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pid_t p;
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int status = 0;
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int ret = 0;
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int r = -1;
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const char *govern = value ? value : initial;
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char *exec_args[] = {
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"/usr/bin/pkexec", LIBEXECDIR "/cpugovctl", "set", (char *)govern, NULL,
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};
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LOG_MSG("Requesting update of governor policy to %s\n", govern);
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if ((p = fork()) < 0) {
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LOG_ERROR("Failed to fork(): %s\n", strerror(errno));
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return false;
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} else if (p == 0) {
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/* Execute the command */
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if ((r = execv(exec_args[0], exec_args)) != 0) {
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LOG_ERROR("Failed to execute cpugovctl helper: %s %s\n", exec_args[1], strerror(errno));
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exit(EXIT_FAILURE);
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}
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_exit(EXIT_SUCCESS);
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} else {
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if (waitpid(p, &status, 0) < 0) {
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LOG_ERROR("Failed to waitpid(%d): %s\n", (int)p, strerror(errno));
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return false;
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}
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/* i.e. sigsev */
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if (!WIFEXITED(status)) {
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LOG_ERROR("Child process '%s' exited abnormally\n", exec_args[0]);
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}
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}
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if ((ret = WEXITSTATUS(status)) != 0) {
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LOG_ERROR("Failed to update cpu governor policy\n");
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return false;
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}
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return true;
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}
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/**
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* Return the cached governor seen at startup
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*/
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const char *get_initial_governor()
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{
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return initial;
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}
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