mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-16 10:20:30 +00:00
124 lines
3.9 KiB
Groff
124 lines
3.9 KiB
Groff
.\"
|
|
.\" Copyright (c) 1998 John D. Polstra
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" 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 February 5, 1998
|
|
.Os FreeBSD
|
|
.Dt DLADDR 3
|
|
.Sh NAME
|
|
.Nm dladdr
|
|
.Nd find the shared object containing a given address
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.Fd #include <dlfcn.h>
|
|
.Ft int
|
|
.Fn dladdr "const void *addr" "Dl_info *info"
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
queries the dynamic linker for information about the shared object
|
|
containing the address
|
|
.Fa addr .
|
|
The information is returned in the structure specified by
|
|
.Fa info .
|
|
The structure contains at least the following members:
|
|
.Bl -tag -width "XXXconst char *dli_fname"
|
|
.It Li "const char *dli_fname"
|
|
The pathname of the shared object containing the address.
|
|
.It Li "void *dli_fbase"
|
|
The base address at which the shared object is mapped into the
|
|
address space of the calling process.
|
|
.It Li "const char *dli_sname"
|
|
The name of the nearest run-time symbol with a value less than or
|
|
equal to
|
|
.Fa addr .
|
|
When possible, the symbol name is returned as it would appear in C
|
|
source code.
|
|
.Pp
|
|
If no symbol with a suitable value is found, both this field and
|
|
.Va dli_saddr
|
|
are set to
|
|
.Dv NULL .
|
|
.It Li "void *dli_saddr"
|
|
The value of the symbol returned in
|
|
.Li dli_sname .
|
|
.El
|
|
.Pp
|
|
.Nm
|
|
is available only in dynamically linked programs.
|
|
.Sh ERRORS
|
|
If a mapped shared object containing
|
|
.Fa addr
|
|
cannot be found,
|
|
.Nm
|
|
returns 0.
|
|
In that case, a message detailing the failure can be retrieved by
|
|
calling
|
|
.Fn dlerror .
|
|
.Pp
|
|
On success, a non-zero value is returned.
|
|
.Sh SEE ALSO
|
|
.Xr rtld 1 ,
|
|
.Xr dlopen 3
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
function first appeared in the Solaris operating system.
|
|
.Sh BUGS
|
|
This implementation is bug-compatible with the Solaris
|
|
implementation. In particular, the following bugs are present:
|
|
.Bl -bullet
|
|
.It
|
|
If
|
|
.Fa addr
|
|
lies in the main executable rather than in a shared library, the
|
|
pathname returned in
|
|
.Va dli_fname
|
|
may not be correct. The pathname is taken directly from
|
|
.Va argv[0]
|
|
of the calling process. When executing a program specified by its
|
|
full pathname, most shells set
|
|
.Va argv[0]
|
|
to the pathname. But this is not required of shells or guaranteed
|
|
by the operating system.
|
|
.It
|
|
If
|
|
.Fa addr
|
|
is of the form
|
|
.Va &func ,
|
|
where
|
|
.Va func
|
|
is a global function, its value may be an unpleasant surprise. In
|
|
dynamically linked programs, the address of a global function is
|
|
considered to point to its program linkage table entry, rather than to
|
|
the entry point of the function itself. This causes most global
|
|
functions to appear to be defined within the main executable, rather
|
|
than in the shared libraries where the actual code resides.
|
|
.It
|
|
Returning 0 as an indication of failure goes against long-standing
|
|
Unix tradition.
|
|
.El
|