.\" $NetBSD: librtld_db.3,v 1.2 2015/09/28 21:50:48 wiz Exp $
.\"-
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.\" This software was developed by Rui Paulo under sponsorship from
.\" the FreeBSD Foundation.
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.\" $FreeBSD: head/lib/librtld_db/librtld_db.3 276294 2014-12-27 08:31:52Z joel $
.\"
.Dd June 10, 2010
.Dt LIBRTLD_DB 3
.Os
.Sh NAME
.Nm librtld_db
.Nd library for run-time linker debugging
.Sh LIBRARY
.Lb librtld_db
.Sh SYNOPSIS
.In rtld_db.h
.Ft void
.Fo rd_delete
.Fa "rd_agent_t *rdap"
.Fc
.Ft char *
.Fo rd_errstr
.Fa "rd_err_e rderr"
.Fc
.Ft rd_err_e
.Fo rd_event_addr
.Fa "rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify"
.Fc
.Ft rd_err_e
.Fo rd_event_enable
.Fa "rd_agent_t *rdap, int onoff"
.Fc
.Ft rd_err_e
.Fo rd_event_getmsg
.Fa "rd_agent_t *rdap, rd_event_msg_t *msg"
.Fc
.Ft rd_err_e
.Fo rd_init
.Fa "int version"
.Fc
.Ft typedef int
.Fo rl_iter_f
.Fa "const rd_loadobj_t *, void *"
.Fc
.Ft rd_err_e
.Fo rd_loadobj_iter
.Fa "rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data"
.Fc
.Ft void
.Fo rd_log
.Fa "const int onoff"
.Fc
.Ft rd_agent_t *
.Fo rd_new
.Fa "struct proc_handle *php"
.Fc
.Ft rd_err_e
.Fo rd_objpad_enable
.Fa "rd_agent_t *rdap, size_t padsize"
.Fc
.Ft rd_err_e
.Fo rd_plt_resolution
.Fa "rd_agent_t *rdap, uintptr_t pc, struct proc *proc"
.Fa "uintptr_t plt_base, rd_plt_info_t *rpi"
.Fc
.Ft rd_err_e
.Fo rd_reset
.Fa "rd_agent_t *rdap"
.Fc
.Sh DESCRIPTION
The
.Nm librtld_db
library provides a debugging interface to the run-time linker (rtld).
This library must be used along with
.Xr libproc 3 .
.Pp
Most library functions take a
.Ft rd_agent_t
argument.
This argument is an opaque structure containing information associated with
the current status of the agent.
.Pp
Before you start using
.Nm
you should call
.Fn rd_init
with the
.Ft RD_VERSION
argument.
This initializes the library to the correct version your program was compiled
with and provides proper ABI stability.
.Pp
What follows is a description of what each function.
.Pp
.Fn rd_new
creates a new
.Nm
agent.
The
.Ft php
argument should be the
.Ft proc_handle
you received from
.Xr libproc 3 .
.Pp
.Fn rd_reset
resets your previously created agent.
.Pp
.Fn rd_delete
deallocates the resources associated with the agent.
.Pp
.Fn rd_errstr
returns an error string describing the error present in
.Ft rderr .
.Pp
.Fn rd_event_enable
enables reporting of events.
This function always returns RD_OK.
.Pp
.Fn rd_event_addr
returns the event address corresponding to the
.Ft event
parameter.
At the moment we only report events of type RD_NOTIFY_BPT.
.Pp
.Fn rd_event_getmsg
returns the message associated with the latest event.
At the moment only RD_POSTINIT events are supported.
.Pp
.Fn rd_loadobj_iter
allows you to iterate over the program's loaded objects.
.Ft cb
is a callback of type
.Fn rl_iter_f .
.Sh RETURN VALUES
Most functions return an
.Ft rd_err_e
type error.
The error codes are described in the header file for this library.
You can get the error string using
.Fn rd_errstr .
.Sh SEE ALSO
.Xr ld 1 ,
.Xr ld.elf_so 1 ,
.Xr ld.so 1 ,
.Xr rtld 1 ,
.Xr libproc 3
.Sh HISTORY
The
.Nm librtld_db
library first appeared in
.Fx 9.0
and was modeled after the same library present in the Solaris operating system.
.Sh AUTHORS
The
.Nm librtld_db
library and this manual page were written by
.An Rui Paulo Aq Mt rpaulo@FreeBSD.org
under sponsorship from the
.Fx
Foundation.
.Sh CAVEATS
The functions
.Fn rd_event_enable ,
.Fn rd_log ,
.Fn rd_objpad_enable ,
and
.Fn rd_plt_resolution
are not yet implemented.