interfereproc
=============

This suite contains two components:

* a set of helper functions for manipulating programs using
  ptrace et al.

* example programs based on the helper functions.

Example 1: redirectfd <pid> <fd> <filename>
Redirect a file descriptor of a running process

Example 2: retronohup <pid>
Retrospectively apply "nohup" to a running process

Example 3: pfiles <pid>...
Show information about a process's open files

Example 4: retrotee <pid> <fd>
Copy the output of a given file descriptor

The helper functions are similar in form to the standard unix function
calls, except that there is a process handle as the first argument to
each function.  The first helper function must be proc_new or
proc_init depending on whether you want to allocate the storage for
the handle or have the helper function allocate the storage. You can
then create a function containing the system calls that you want to
execute. This procedure MUST begin PROC_BEGIN and end PROG_END:

int myroutine(struct process *proc)
{
        PROC_BEGIN(proc);
	[system calls]
        PROC_END(proc);
}

The system calls are actually macros that cause myroutine to return
while system calls are in progress. See interfere.h for details.

The public members of struct process are:
  pid - the process id of the process being manipulated
  retval - the return value of the system call (or -1 on error)
  last_error - the errno value from this system call (or 0 on success)
  error - the last non-zero errno value
  exitsig - the signal to send to the process when detaching

The simplest example program is redirectfd.c.
For an example showing multiple programs being traced, see pfiles.c.

For installation instructions, see INSTALL.
For copying permission, see COPYING.

Copyright (C) 2002 Peter Benie <peterb@chiark.greenend.org.uk>