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https://github.com/FeralInteractive/gamemode.git
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17241deccb
When there are not valid standard file descriptors then strange things can happen. When new file descriptors are opened, they will take the place of the former standard file descriptors and when e.g. somebody calls printf() they will write to some file descriptor that is not prepared for it. This would already happen during PLOG_MSG() in gamemoded. Actually this also causes a SIGABRT when calling gamemoded like this: ```bash gamemoded -d ``` This is due to a bug [1] in systemd that causes an assertion to be triggered. This shows that file descriptor zero is in this case being replaced by a UNIX domain socket representing the connection to the D-Bus session bus. Therefore instead of just closing the standard file descriptors, replace them by appropriate file descriptors refering to /dev/null. [1]: https://github.com/systemd/systemd/issues/8080
82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
/*
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Copyright (c) 2017-2018, 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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#include "daemonize.h"
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#include "logging.h"
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#include <fcntl.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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/**
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* Helper to perform standard UNIX daemonization
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*/
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void daemonize(const char *name)
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{
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/* Initial fork */
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pid_t pid = fork();
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if (pid < 0) {
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FATAL_ERRORNO("Failed to fork");
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}
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if (pid != 0) {
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LOG_MSG("Daemon launched as %s...\n", name);
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exit(EXIT_SUCCESS);
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}
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/* Fork a second time */
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pid = fork();
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if (pid < 0) {
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FATAL_ERRORNO("Failed to fork");
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} else if (pid > 0) {
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exit(EXIT_SUCCESS);
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}
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/* Now continue execution */
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umask(0022);
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if (setsid() < 0) {
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FATAL_ERRORNO("Failed to create process group\n");
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}
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if (chdir("/") < 0) {
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FATAL_ERRORNO("Failed to change to root directory\n");
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}
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/* replace standard file descriptors by /dev/null */
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int devnull_r = open("/dev/null", O_RDONLY);
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int devnull_w = open("/dev/null", O_WRONLY);
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dup2(devnull_r, STDIN_FILENO);
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dup2(devnull_w, STDOUT_FILENO);
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dup2(devnull_w, STDERR_FILENO);
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close(devnull_r);
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close(devnull_w);
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}
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