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.\" Copyright 2015 Joyent, Inc.
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.Dd November 27, 2023
.Dt PR_UNLINK 3PROC
.Os
.Sh NAME
.Nm pr_unlink
.Nd inject unlink system call into victim process
.Sh LIBRARY
.Lb libproc
.Sh SYNOPSIS
.In libproc.h
.Ft int
.Fo pr_unlink
.Fa "struct ps_prochandle *P"
.Fa "const char *path"
.Fc
.Sh DESCRIPTION
The
.Fn pr_unlink
function injects the
.Xr unlink 2
system call into the target process
.Fa P
by means of the agent LWP.
If the process handle
.Fa P
is the value
.Dv NULL
then this will be equivalent to calling
.Xr unlink 2
on the currently running process.
.Pp
The argument
.Fa path
has the same meaning as in
.Xr unlink 2 .
See
.Xr unlink 2
for the full description and purpose of the
.Sy unlink
system call and its arguments.
.Pp
The
.Fn pr_unlink
function only works on active processes.
Process handles that correspond to core files, zombie processes, or ELF objects
do not support system call injection.
.Sh RETURN VALUES
Upon successful completion, the
.Fn pr_unlink
function's return value is that described in
.Xr unlink 2 .
Otherwise,
.Sy -1
is returned and
.Sy errno
is set to
.Er ENOSYS
to indicate that the system call could not be injected.
.Sh ERRORS
For the full list of errors see the
.Sy ERRORS
section in
.Xr unlink 2 .
.Pp
The
.Fn pr_unlink
function will fail if:
.Bl -tag -width Er
.It Er ENOSYS
An error occurred while trying to invoke the agent LWP and inject a
system call in the process handle
.Fa P
or the process handle
.Fa P
does not support system call injection.
.El
.Sh INTERFACE STABILITY
.Sy Uncommitted
.Sh MT-LEVEL
See
.Sy LOCKING
in
.Xr libproc 3LIB .
.Sh SEE ALSO
.Xr unlink 2 ,
.Xr libproc 3LIB ,
.Xr proc 5