84d9c625bf
- Fix for possible unset uid/gid in toproto
- Fix for default mtree style
- Update libelf
- Importing libexecinfo
- Resynchronize GCC, mpc, gmp, mpfr
- build.sh: Replace params with show-params.
This has been done as the make target has been renamed in the same
way, while a new target named params has been added. This new
target generates a file containing all the parameters, instead of
printing it on the console.
- Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
get getservbyport() out of the inner loop
Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
159 lines
4.7 KiB
Groff
159 lines
4.7 KiB
Groff
.\" $NetBSD: backtrace.3,v 1.5 2013/08/22 17:08:43 christos Exp $
|
|
.\"
|
|
.\" Copyright (c) 2012 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Christos Zoulas
|
|
.\"
|
|
.\" 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
|
|
.\"
|
|
.Dd May 26, 2012
|
|
.Dt BACKTRACE 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm backtrace
|
|
.Nd fill in the backtrace of the currently executing thread
|
|
.Sh LIBRARY
|
|
.Lb libexecinfo
|
|
.Sh SYNOPSIS
|
|
.In execinfo.h
|
|
.Ft size_t
|
|
.Fn backtrace "void **addrlist" "size_t len"
|
|
.Ft "char **"
|
|
.Fn backtrace_symbols "void * const *addrlist" "size_t len"
|
|
.Ft int
|
|
.Fn backtrace_symbols_fd "void * const *addrlist" "size_t len" "int fd"
|
|
.Ft "char **"
|
|
.Fn backtrace_symbols_fmt "void * const *addrlist" "size_t len" "const char *fmt"
|
|
.Ft int
|
|
.Fn backtrace_symbols_fmt_fd "void * const *addrlist" "size_t len" "const char *fmt" "int fd"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn backtrace
|
|
function places into the array pointed by
|
|
.Fa addrlist
|
|
the array of the values of the program counter for each frame called up to
|
|
.Fa len
|
|
frames.
|
|
The number of frames found (which can be fewer than
|
|
.Fa len )
|
|
is returned.
|
|
.Pp
|
|
The
|
|
.Fn backtrace_symbols_fmt
|
|
function takes an array of previously filled addresses from
|
|
.Fn backtrace
|
|
in
|
|
.Fa addrlist
|
|
of
|
|
.Fa len
|
|
elements, and uses
|
|
.Fa fmt
|
|
to format them.
|
|
The formatting characters available are:
|
|
.Bl -tag -width a -offset indent
|
|
.It Dv a
|
|
The numeric address of each element as would be printed using %p.
|
|
.It Dv n
|
|
The name of the nearest function symbol (smaller than the address element)
|
|
as determined by
|
|
.Xr dladdr 3
|
|
if the symbol was dynamic, or looked up in the executable if static and
|
|
the /proc filesystem is available to determine the executable path.
|
|
.It Dv d
|
|
The difference of the symbol address and the address element printed
|
|
using 0x%tx.
|
|
.It Dv D
|
|
The difference of the symbol addresss and the address element printed using
|
|
+0x%tx if non-zero, or nothing if zero.
|
|
.It Dv f
|
|
The filename of the symbol as determined by
|
|
.Xr dladdr 3 .
|
|
.El
|
|
.Pp
|
|
The array of formatted strings is returned as a contiguous memory address which
|
|
can be freed by a single
|
|
.Xr free 3 .
|
|
.Pp
|
|
The
|
|
.Fn backtrace_symbols
|
|
function is equivalent of calling
|
|
.Fn backtrace_symbols_fmt
|
|
with a format argument of
|
|
.Dv "%a <%n%D> at %f"
|
|
.Pp
|
|
The
|
|
.Fn backtrace_symbols_fd
|
|
and
|
|
.Fn backtrace_symbols_fmt_fd
|
|
are similar to the non _fd named functions, only instead of returning
|
|
an array or strings, they print a new-line separated array of strings in
|
|
fd, and return
|
|
.Dv 0
|
|
on success and
|
|
.Dv \-1
|
|
on failure.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn backtrace
|
|
function returns the number of elements that were filled in the backtrace.
|
|
The
|
|
.Fn backtrace_symbols
|
|
and
|
|
.Fn backtrace_symbols_fmt
|
|
return a string array on success, and
|
|
.Dv NULL
|
|
on failure, setting
|
|
.Va errno .
|
|
Diagnostic output may also be produced by the ELF symbol lookup functions.
|
|
.Sh SEE ALSO
|
|
.Xr dladdr 3 ,
|
|
.Xr elf 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn backtrace
|
|
library of functions first appeared in
|
|
.Nx 7.0 .
|
|
.Sh BUGS
|
|
.Bl -enum
|
|
.It
|
|
Errors should not be printed but communicated to the caller differently.
|
|
.It
|
|
Because these functions use
|
|
.Xr elf 3
|
|
this is a separate library instead of being part of libc/libutil
|
|
so that no library dependencies are introduced.
|
|
.It
|
|
The Linux versions of the functions (there are no _fmt variants) use
|
|
.Ft int
|
|
instead of
|
|
.Ft size_t
|
|
arguments.
|
|
.It
|
|
Since
|
|
.Xr dladdr 3
|
|
only deals with dynamic symbols, we need to find the symbols from the main
|
|
portion of the program.
|
|
For that we need to locate the executable, and we use procfs for
|
|
finding it, which is not portable.
|
|
.El
|