Every process now has an init process like it has a session, and each session belong to an init. Orphaned processes are reparented to its init process. All descendent processes are SIGKILL'd when an init process exits and creating additional processes/threads fails. Add setinit(2) for becoming the init process for your child processes and add getinit(2) for locating your init process. Add TIOCSCTTY force flag that releases a terminal from its current session and makes it the controlling terminal for the current session. This ioctl is essential to transferring the controlling terminal to a nested init, which has its own session. Add TIOCUCTTY that releases the terminal as the controlling terminal for its current session. Remove INIT_PID as it is replaced by getinit(2).
47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
/*
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* Copyright (c) 2021, 2022, 2024 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* halt.c
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* Halts the computer.
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*/
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#include <sys/types.h>
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#include <err.h>
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#include <getopt.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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int main(int argc, char* argv[])
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{
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int opt;
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while ( (opt = getopt(argc, argv, "")) != -1 )
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{
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switch ( opt )
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{
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default: return 1;
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}
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}
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if ( optind < argc )
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errx(1, "extra operand: %s", argv[optind]);
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pid_t init_pid = getinit(0);
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if ( kill(init_pid, SIGQUIT) < 0 )
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err(1, "kill: %" PRIdPID, init_pid);
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return 0;
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}
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