LIBRTLD_DB(3)

NAME
librtld_db - library for run-time linker debugging

LIBRARY
librtld_db

SYNOPSIS
#include <rtld_db.h>
void
rd_delete(rd_agent_t *rdap);
char *
rd_errstr(rd_err_e rderr);
rd_err_e
rd_event_addr(rd_agent_t *rdap, rd_event_e event, rd_notify_t *notify);
rd_err_e
rd_event_enable(rd_agent_t *rdap, int onoff);
rd_err_e
rd_event_getmsg(rd_agent_t *rdap, rd_event_msg_t *msg);
rd_err_e
rd_init(int version);
typedef int
rl_iter_f(const rd_loadobj_t *, void *);
rd_err_e
rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data);
void
rd_log(const int onoff);
rd_agent_t *
rd_new(struct proc_handle *php);
rd_err_e
rd_objpad_enable(rd_agent_t *rdap, size_t padsize);
rd_err_e
rd_plt_resolution(rd_agent_t *rdap, uintptr_t pc, struct proc *proc, uintptr_t plt_base, rd_plt_info_t *rpi);
rd_err_e
rd_reset(rd_agent_t *rdap);

DESCRIPTION
The librtld_db library provides a debugging interface to the run-time linker (rtld). This library must be used along with libproc(3).

Most library functions take a rd_agent_t argument. This argument is an opaque structure containing information associated with the current status of the agent.

Before you start using librtld_db you should call rd_init() with the RD_VERSION argument. This initializes the library to the correct version your program was compiled with and provides proper ABI stability.

What follows is a description of what each function.

rd_new() creates a new librtld_db agent. The php argument should be the proc_handle you received from libproc(3).

rd_reset() resets your previously created agent.

rd_delete() deallocates the resources associated with the agent.

rd_errstr() returns an error string describing the error present in rderr.

rd_event_enable() enables reporting of events. This function always returns RD_OK.

rd_event_addr() returns the event address corresponding to the event parameter. At the moment we only report events of type RD_NOTIFY_BPT.

rd_event_getmsg() returns the message associated with the latest event. At the moment only RD_POSTINIT events are supported.

rd_loadobj_iter() allows you to iterate over the program's loaded objects. cb is a callback of type rl_iter_f().

RETURN VALUES
Most functions return an rd_err_e type error. The error codes are described in the header file for this library. You can get the error string using rd_errstr().

SEE ALSO
ld(1), ld.elf_so(1), ld.so(1), rtld(1), libproc(3)

HISTORY
The librtld_db library first appeared in FreeBSD 9.0 and was modeled after the same library present in the Solaris operating system.

AUTHORS
The librtld_db library and this manual page were written by Rui Paulo <rpaulo@FreeBSD.org> under sponsorship from the FreeBSD Foundation.

CAVEATS
The functions rd_event_enable(), rd_log(), rd_objpad_enable(), and rd_plt_resolution() are not yet implemented.