mirror of
https://github.com/tobast/libunwind-eh_elf.git
synced 2024-12-23 20:03:43 +01:00
224 lines
4.8 KiB
Groff
224 lines
4.8 KiB
Groff
'\" t
|
|
.\" Manual page created with latex2man on Thu Aug 5 10:20:31 CEST 2004
|
|
.\" NOTE: This file is generated, DO NOT EDIT.
|
|
.de Vb
|
|
.ft CW
|
|
.nf
|
|
..
|
|
.de Ve
|
|
.ft R
|
|
|
|
.fi
|
|
..
|
|
.TH "LIBUNWIND\-PTRACE" "3" "05 August 2004" "Programming Library " "Programming Library "
|
|
.SH NAME
|
|
libunwind\-ptrace
|
|
\-\- ptrace() support in libunwind
|
|
.PP
|
|
.SH SYNOPSIS
|
|
|
|
.PP
|
|
#include <libunwind\-ptrace.h>
|
|
.br
|
|
.PP
|
|
unw_accessors_t
|
|
_UPT_accessors;
|
|
.br
|
|
.PP
|
|
void *_UPT_create(pid_t);
|
|
.br
|
|
void
|
|
_UPT_destroy(void *);
|
|
.br
|
|
.PP
|
|
int
|
|
_UPT_find_proc_info(unw_addr_space_t,
|
|
unw_word_t,
|
|
unw_proc_info_t *,
|
|
int,
|
|
void *);
|
|
.br
|
|
void
|
|
_UPT_put_unwind_info(unw_addr_space_t,
|
|
unw_proc_info_t *,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_get_dyn_info_list_addr(unw_addr_space_t,
|
|
unw_word_t *,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_access_mem(unw_addr_space_t,
|
|
unw_word_t,
|
|
unw_word_t *,
|
|
int,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_access_reg(unw_addr_space_t,
|
|
unw_regnum_t,
|
|
unw_word_t *,
|
|
int,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_access_fpreg(unw_addr_space_t,
|
|
unw_regnum_t,
|
|
unw_fpreg_t *,
|
|
int,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_get_proc_name(unw_addr_space_t,
|
|
unw_word_t,
|
|
char *,
|
|
size_t,
|
|
unw_word_t *,
|
|
void *);
|
|
.br
|
|
int
|
|
_UPT_resume(unw_addr_space_t,
|
|
unw_cursor_t *,
|
|
void *);
|
|
.br
|
|
.PP
|
|
.SH DESCRIPTION
|
|
|
|
.PP
|
|
The ptrace(2)
|
|
system\-call makes it possible for a process to
|
|
gain access to the machine\-state and virtual memory of \fIanother\fP
|
|
process. With the right set of call\-back routines, it is therefore
|
|
possible to hook up libunwind
|
|
to another process via
|
|
ptrace(2).
|
|
While it\&'s not very difficult to do so directly,
|
|
libunwind
|
|
further facilitates this task by providing
|
|
ready\-to\-use callbacks for this purpose. The routines and variables
|
|
implementing this facility use a name\-prefix of _UPT,
|
|
which is
|
|
stands for ``unwind\-via\-ptrace\&''\&.
|
|
.PP
|
|
An application that wants to use the _UPT\-facility
|
|
first needs
|
|
to create a new libunwind
|
|
address\-space that represents the
|
|
target process. This is done by calling
|
|
unw_create_addr_space().
|
|
In many cases, the application
|
|
will simply want to pass the address of _UPT_accessors
|
|
as the
|
|
first argument to this routine. Doing so will ensure that
|
|
libunwind
|
|
will be able to properly unwind the target process.
|
|
However, in special circumstances, an application may prefer to use
|
|
only portions of the _UPT\-facility.
|
|
For this reason, the
|
|
individual callback routines (_UPT_find_proc_info(),
|
|
_UPT_put_unwind_info(),
|
|
etc.) are also available for direct
|
|
use. Of course, the addresses of these routines could also be picked
|
|
up from _UPT_accessors,
|
|
but doing so would prevent static
|
|
initialization. Also, when using _UPT_accessors,
|
|
\fIall\fP
|
|
the callback routines will be linked into the application, even if
|
|
they are never actually called.
|
|
.PP
|
|
Next, the application can turn on ptrace\-mode on the target process,
|
|
either by forking a new process, invoking PTRACE_TRACEME,
|
|
and
|
|
then starting the target program (via execve(2)),
|
|
or by
|
|
directly attaching to an already running process (via
|
|
PTRACE_ATTACH).
|
|
Either way, once the process\-ID (pid) of the
|
|
target process is known, a _UPT\-info\-structure
|
|
can be created
|
|
by calling _UPT_create(),
|
|
passing the pid of the target process
|
|
as the only argument. The returned void\-pointer then needs to be
|
|
passed as the ``argument\&'' pointer (third argument) to
|
|
unw_init_remote().
|
|
.PP
|
|
The _UPT_resume()
|
|
routine can be used to resume execution of
|
|
the target process. It simply invokes ptrace(2)
|
|
with a command
|
|
value of PTRACE_CONT\&.
|
|
.PP
|
|
When the application is done using libunwind
|
|
on the target
|
|
process, _UPT_destroy()
|
|
needs to be called, passing it the
|
|
void\-pointer that was returned by the corresponding call to
|
|
_UPT_create().
|
|
This ensures that all memory and other
|
|
resources are freed up.
|
|
.PP
|
|
.SH AVAILABILITY
|
|
|
|
.PP
|
|
Since ptrace(2)
|
|
works within a single machine only, the
|
|
_UPT\-facility
|
|
by definition is not available in
|
|
libunwind\-versions
|
|
configured for cross\-unwinding.
|
|
.PP
|
|
.SH THREAD SAFETY
|
|
|
|
.PP
|
|
The _UPT\-facility
|
|
assumes that a single _UPT\-info
|
|
structure is never shared between threads. Because of this, no
|
|
explicit locking is used. As long as only one thread uses
|
|
a _UPT\-info
|
|
structure at any given time, this facility
|
|
is thread\-safe.
|
|
.PP
|
|
.SH RETURN VALUE
|
|
|
|
.PP
|
|
_UPT_create()
|
|
may return a NULL
|
|
pointer if it fails
|
|
to create the _UPT\-info\-structure
|
|
for any reason. For the
|
|
current implementation, the only reason this call may fail is when the
|
|
system is out of memory.
|
|
.PP
|
|
.SH FILES
|
|
|
|
.PP
|
|
.TP
|
|
libunwind\-ptrace.h
|
|
Headerfile to include when using the
|
|
interface defined by this library.
|
|
.TP
|
|
\fB\-l\fPunwind\-ptrace \fB\-l\fPunwind\-generic
|
|
Linker\-switches to add when building a program that uses the
|
|
functions defined by this library.
|
|
.PP
|
|
.SH SEE ALSO
|
|
|
|
.PP
|
|
execve(2),
|
|
libunwind(3),
|
|
ptrace(2)
|
|
.PP
|
|
.SH AUTHOR
|
|
|
|
.PP
|
|
David Mosberger\-Tang
|
|
.br
|
|
Hewlett\-Packard Labs
|
|
.br
|
|
Palo\-Alto, CA 94304
|
|
.br
|
|
Email: \fBdavidm@hpl.hp.com\fP
|
|
.br
|
|
WWW: \fBhttp://www.hpl.hp.com/research/linux/libunwind/\fP\&.
|
|
.\" NOTE: This file is generated, DO NOT EDIT.
|