Proc Parent

`proc_parent()`

Returns the parent handle of the supplied process.

Description

The proc_parent() function is used to retrieve the parent handle of a given process. It takes a process identifier (PID) as input and returns the PID of the parent process.

In POSIX systems, each process has a parent process except for the initial process, which is typically assigned a parent of PID 1 (init process). The parent process is responsible for creating and managing its child processes.

Syntax

  ;;; Returns the parent handle of a particular process
  (@interface func (export "proc_parent")
    ;;; Handle of the process to get the parent handle for
    (param $pid $pid)
    (result $error (expected $pid (error $errno)))
  )

Parameters

ctx: The function environment.
pid: The process identifier (PID) of the process whose parent is to be retrieved.
ret_parent: Pointer to store the returned parent process ID.

Return Value

The function returns an Errno value indicating the result of the operation. If the operation is successful, it returns Errno::Success. If the supplied process does not exist or the current process is not the parent, it returns Errno::Badf.

Logging

This function is instrumented with debug level logging. It includes the following field for debugging purposes:

pid: The process identifier (PID) of the supplied process.
parent: The parent process ID.

Note

The proc_parent() function is used to retrieve the parent handle of a given process.
It checks if the supplied pid matches the current process's PID. If they match, it retrieves the parent PID using the ppid() method of the current process.
If the supplied pid does not match the current process's PID, it attempts to retrieve the process from the control plane using the get_process() method.
The function stores the parent PID in the specified ret_parent pointer.
The function returns Errno::Badf if the supplied process does not exist or the current process is not the parent.

proc_id proc_join