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Import the librtld_db library. This is needed by userland DTrace.

Browse Source 
This is not yet enabled in the build because I also need to import a new
version of libproc.

Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Rui Paulo 2010-07-31 14:26:10 +00:00
parent 2c16c8d7e5
commit cb31498865
4 changed files with 581 additions and 0 deletions
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14
lib/librtld_db/Makefile Normal file
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# $FreeBSD$
.include <bsd.own.mk>
LIB= rtld_db
SHLIB_MAJOR= 1
MAN= librtld_db.3
SRCS= rtld_db.c
INCS= rtld_db.h
CFLAGS+= -I${.CURDIR}
.include <bsd.lib.mk>

191
lib/librtld_db/librtld_db.3 Normal file
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.\"-
.\" Copyright (c) 2010 The FreeBSD Foundation
.\" All rights reserved.
.\"
.\" This software was developed by Rui Paulo under sponsorship from
.\" the FreeBSD Foundation.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.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_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
dealocates 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 in the
.Ft event
paramenter.
At the moment we only report RD_NOTIFY_BPT events.
.Pp
.Fn rd_event_getmsg
returns the message assoicated wit hthe 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 CAVEATS
The functions
.Fn rd_event_enable ,
.Fn rd_log ,
.Fn rd_objpad_enable
and
.Fn rd_plt_resolution
are not yet implemented.
.Sh SEE ALSO
.Xr ld 1 ,
.Xr ld-elf.so.1 1 ,
.Xr ld.so 1 ,
.Xr libproc 3 ,
.Xr rtld 1
.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 rpaulo@FreeBSD.org
under sponsorship from the FreeBSD Foundation.

226
lib/librtld_db/rtld_db.c Normal file
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/*
* Copyright (c) 2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Rui Paulo under sponsorship from the
* FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <machine/_inttypes.h>
#include <sys/types.h>
#include <sys/user.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <libproc.h>
#include <libutil.h>
#include "rtld_db.h"
static int _librtld_db_debug = 0;
#define DPRINTF(...) do { \
if (_librtld_db_debug) { \
fprintf(stderr, "librtld_db: DEBUG: "); \
fprintf(stderr, __VA_ARGS__); \
} \
} while (0)
void
rd_delete(rd_agent_t *rdap)
{
free(rdap);
}
const char *
rd_errstr(rd_err_e rderr)
{
switch (rderr) {
case RD_ERR:
return "generic error";
case RD_OK:
return "no error";
case RD_NOCAPAB:
return "capability not supported";
case RD_DBERR:
return "database error";
case RD_NOBASE:
return "NOBASE";
case RD_NOMAPS:
return "NOMAPS";
default:
return "unknown error";
}
}
rd_err_e
rd_event_addr(rd_agent_t *rdap, rd_event_e event __unused, rd_notify_t *notify)
{
DPRINTF("%s rdap %p notify %p\n", __func__, rdap, notify);
notify->type = RD_NOTIFY_BPT;
notify->u.bptaddr = rdap->rda_addr;
return (RD_OK);
}
rd_err_e
rd_event_enable(rd_agent_t *rdap __unused, int onoff)
{
DPRINTF("%s onoff %d\n", __func__, onoff);
return (RD_OK);
}
rd_err_e
rd_event_getmsg(rd_agent_t *rdap __unused, rd_event_msg_t *msg)
{
DPRINTF("%s\n", __func__);
msg->type = RD_POSTINIT;
msg->u.state = RD_CONSISTENT;
return (RD_OK);
}
rd_err_e
rd_init(int version)
{
char *debug = NULL;
if (version == RD_VERSION) {
debug = getenv("LIBRTLD_DB_DEBUG");
_librtld_db_debug = debug ? atoi(debug) : 0;
return (RD_OK);
} else
return (RD_NOCAPAB);
}
rd_err_e
rd_loadobj_iter(rd_agent_t *rdap, rl_iter_f *cb, void *clnt_data)
{
int cnt, i, lastvn = 0;
rd_loadobj_t rdl;
struct kinfo_vmentry *kves, *kve;
DPRINTF("%s\n", __func__);
if ((kves = kinfo_getvmmap(proc_getpid(rdap->rda_php), &cnt)) == NULL) {
warn("ERROR: kinfo_getvmmap() failed");
return (RD_ERR);
}
for (i = 0; i < cnt; i++) {
kve = kves + i;
if (kve->kve_type == KVME_TYPE_VNODE)
lastvn = i;
memset(&rdl, 0, sizeof(rdl));
/*
* Map the kinfo_vmentry struct to the rd_loadobj structure.
*/
rdl.rdl_saddr = kve->kve_start;
rdl.rdl_eaddr = kve->kve_end;
rdl.rdl_offset = kve->kve_offset;
if (kve->kve_protection & KVME_PROT_READ)
rdl.rdl_prot |= RD_RDL_R;
if (kve->kve_protection & KVME_PROT_WRITE)
rdl.rdl_prot |= RD_RDL_W;
if (kve->kve_protection & KVME_PROT_EXEC)
rdl.rdl_prot |= RD_RDL_X;
strlcpy(rdl.rdl_path, kves[lastvn].kve_path,
sizeof(rdl.rdl_path));
(*cb)(&rdl, clnt_data);
}
free(kves);
return (RD_OK);
}
void
rd_log(const int onoff)
{
DPRINTF("%s\n", __func__);
(void)onoff;
}
rd_agent_t *
rd_new(struct proc_handle *php)
{
rd_agent_t *rdap;
rdap = malloc(sizeof(rd_agent_t));
if (rdap) {
memset(rdap, 0, sizeof(rd_agent_t));
rdap->rda_php = php;
rd_reset(rdap);
}
return (rdap);
}
rd_err_e
rd_objpad_enable(rd_agent_t *rdap, size_t padsize)
{
DPRINTF("%s\n", __func__);
(void)rdap;
(void)padsize;
return (RD_ERR);
}
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)
{
DPRINTF("%s\n", __func__);
(void)rdap;
(void)pc;
(void)proc;
(void)plt_base;
(void)rpi;
return (RD_ERR);
}
rd_err_e
rd_reset(rd_agent_t *rdap)
{
GElf_Sym sym;
if (proc_name2sym(rdap->rda_php, "ld-elf.so.1", "r_debug_state",
&sym) < 0)
return (RD_ERR);
DPRINTF("found r_debug_state at 0x%lx\n", (unsigned long)sym.st_value);
rdap->rda_addr = sym.st_value;
return (RD_OK);
}

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lib/librtld_db/rtld_db.h Normal file
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/*
* Copyright (c) 2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Rui Paulo under sponsorship from the
* FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _RTLD_DB_H_
#define _RTLD_DB_H_
#include <sys/param.h>
#include <sys/cdefs.h>
#include <sys/types.h>
#define RD_VERSION 1
typedef enum {
RD_OK,
RD_ERR,
RD_DBERR,
RD_NOCAPAB,
RD_NODYNAM,
RD_NOBASE,
RD_NOMAPS
} rd_err_e;
typedef struct rd_agent {
struct proc_handle *rda_php;
uintptr_t rda_addr; /* address of r_debug_state */
} rd_agent_t;
typedef struct rd_loadobj {
uintptr_t rdl_saddr; /* start address */
uintptr_t rdl_eaddr; /* end address */
uint32_t rdl_offset;
uint8_t rdl_prot;
#define RD_RDL_R 0x01
#define RD_RDL_W 0x02
#define RD_RDL_X 0x04
enum {
RDL_TYPE_NONE = 0,
RDL_TYPE_DEF,
RDL_TYPE_VNODE,
RDL_TYPE_SWAP,
RDL_TYPE_DEV,
/* XXX some types missing */
RDL_TYPE_UNKNOWN = 255
} rdl_type;
unsigned char rdl_path[PATH_MAX];
} rd_loadobj_t;
typedef enum {
RD_NONE = 0,
RD_PREINIT,
RD_POSTINIT,
RD_DLACTIVITY
} rd_event_e;
typedef enum {
RD_NOTIFY_BPT,
RD_NOTIFY_AUTOBPT,
RD_NOTIFY_SYSCALL
} rd_notify_e;
typedef struct rd_notify {
rd_notify_e type;
union {
uintptr_t bptaddr;
long syscallno;
} u;
} rd_notify_t;
typedef enum {
RD_NOSTATE = 0,
RD_CONSISTENT,
RD_ADD,
RD_DELETE
} rd_state_e;
typedef struct rd_event_msg {
rd_event_e type;
union {
rd_state_e state;
} u;
} rd_event_msg_t;
typedef enum {
RD_RESOLVE_NONE,
RD_RESOLVE_STEP,
RD_RESOLVE_TARGET,
RD_RESOLVE_TARGET_STEP
} rd_skip_e;
typedef struct rd_plt_info {
rd_skip_e pi_skip_method;
long pi_nstep;
uintptr_t pi_target;
uintptr_t pi_baddr;
unsigned int pi_flags;
} rd_plt_info_t;
#define RD_FLG_PI_PLTBOUND 0x0001
__BEGIN_DECLS
struct proc_handle;
void rd_delete(rd_agent_t *);
const char *rd_errstr(rd_err_e);
rd_err_e rd_event_addr(rd_agent_t *, rd_event_e, rd_notify_t *);
rd_err_e rd_event_enable(rd_agent_t *, int);
rd_err_e rd_event_getmsg(rd_agent_t *, rd_event_msg_t *);
rd_err_e rd_init(int);
typedef int rl_iter_f(const rd_loadobj_t *, void *);
rd_err_e rd_loadobj_iter(rd_agent_t *, rl_iter_f *, void *);
void rd_log(const int);
rd_agent_t *rd_new(struct proc_handle *);
rd_err_e rd_objpad_enable(rd_agent_t *, size_t);
struct proc;
rd_err_e rd_plt_resolution(rd_agent_t *, uintptr_t, struct proc *,
uintptr_t, rd_plt_info_t *);
rd_err_e rd_reset(rd_agent_t *);
__END_DECLS
#endif /* _RTLD_DB_H_ */