6e51c1ae51
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).
76 lines
1.5 KiB
Groff
76 lines
1.5 KiB
Groff
.Dd June 18, 2024
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.Dt SETINIT 2
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.Os
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.Sh NAME
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.Nm setinit
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.Nd become and locate init
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.Sh SYNOPSIS
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.In unistd.h
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.Ft int
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.Fn getinit "pid_t pid"
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.Ft int
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.Fn setinit void
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.Sh DESCRIPTION
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.Fn setinit
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sets the current process as the init process for itself and its subsequently
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created descendant processes.
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.Fn setinit
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runs
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.Xr setsid 2
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to create a new session (and process group) and can fail for the same reasons as
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.Xr setsid 2 .
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.Pp
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.Fn getinit
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returns the init process for the process specified in
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.Fa pid ,
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or the current process if
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.Fa pid
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is zero.
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.Pp
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Orphaned descendant processes are reparented to their init process.
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If an init process exits, all descendant processes atomically receive the
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.Dv SIGKILL
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signal and become unable to create new processes and threads.
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.Sh RETURN VALUES
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.Fn setinit
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returns the pid of the init process (the current process) on success, or -1 on
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error and
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.Va error
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is set appropriately.
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.Pp
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.Fn getinit
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returns the returns the pid of the init process, or -1 on
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error and
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.Va error
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is set appropriately.
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.Sh ERRORS
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.Fn setinit
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will fail if:
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.Bl -tag -width "12345678"
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.It Er EPERM
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The process is already a process group leader, a session leader, or an init
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process.
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.El
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.Pp
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.Fn getinit
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will fail if:
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.Bl -tag -width "12345678"
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.It Er ESRCH
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The process specified in
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.Fa pid
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does not exist.
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.El
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.Sh SEE ALSO
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.Xr getpgrp 2 ,
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.Xr getsid 2 ,
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.Xr psctl 2 ,
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.Xr setpgrp 2 ,
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.Xr setsid 2 ,
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.Xr init 8
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.Sh HISTORY
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The
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.Fn getinit
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and
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.Fn setinit
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system calls originally appeared in Sortix 1.1.
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