116 lines
3.3 KiB
Groff
116 lines
3.3 KiB
Groff
.\" Copyright (c) 2005 Mark Kettenis
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.\" Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
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.\"
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.\" Permission to use, copy, modify, and distribute this software for any
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" copyright notice and this permission notice appear in all copies.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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.\"
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.\" $OpenBSD: dl_iterate_phdr.3,v 1.3 2007/05/31 19:19:48 jmc Exp $
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.\" $FreeBSD$
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.Dd February 15, 2012
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.Dt DL_ITERATE_PHDR 3
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.Os
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.Sh NAME
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.Nm dl_iterate_phdr
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.Nd iterate over program headers
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.Sh LIBRARY
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For the dynamically linked binaries, the service is provided by
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.Xr ld-elf.so.1 1
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dynamic linker.
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Statically linked programs use an implementation of
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.Fn dl_iterate_phdr
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from libc.
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.Sh SYNOPSIS
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.Fd #include <link.h>
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.Ft int
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.Fn dl_iterate_phdr "int (*callback)(struct dl_phdr_info *, size_t, void *)" "void *data"
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.Sh DESCRIPTION
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The
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.Fn dl_iterate_phdr
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function iterates over all ELF objects loaded into a process's
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address space, calling
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.Fa callback
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for each object, passing it information about the object's
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program headers and the
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.Fa data
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argument.
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The iteration is aborted when all objects are passed, or when the next
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.Fa callback
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call returns non-zero value.
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The information about the program headers is passed in a structure
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that is defined as:
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.Bd -literal
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struct dl_phdr_info {
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Elf_Addr dlpi_addr;
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const char *dlpi_name;
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const Elf_Phdr *dlpi_phdr;
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Elf_Half dlpi_phnum;
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unsigned long long int dlpi_adds;
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unsigned long long int dlpi_subs;
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size_t dlpi_tls_modid;
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void *dlpi_tls_data;
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};
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.Ed
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.Pp
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The members of
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.Li struct dl_phdr_info
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have the following meaning:
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.Bl -tag -width dlpi_tls_modid
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.It Fa dlpi_addr
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The base address at which the object is mapped into the address
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space of the calling process.
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.It Fa dlpi_name
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The name of the ELF object.
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.It Fa dlpi_phdr
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A pointer to the object's program headers.
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.It Fa dlpi_phnum
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The number of program headers in the object.
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.It Fa dlpi_adds
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The counter of the object loads performed by the dynamic linker.
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.It Fa dlpi_subs
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The counter of the object unloads performed by the dynamic linker.
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.It Fa dlpi_tls_modid
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The TLS index of the object.
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.It Fa dlpi_tls_data
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A pointer to the initialization data for the object TLS segment.
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.El
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.Pp
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Future versions of
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.Fx
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might add more members to this structure.
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To make it possible for programs to check whether any new members have
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been added, the size of the structure is passed as an second argument to
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.Fa callback .
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.Pp
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The third argument to callback is the
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.Fa data
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value passed to the call to
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.Fn dl_iterate_phdr ,
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allowing the
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.Fa callback
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to have a context.
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.Sh RETURN VALUES
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The
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.Fn dl_iterate_phdr
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returns the value returned by the last
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.Fa callback
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call executed.
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.Sh SEE ALSO
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.Xr ld 1 ,
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.Xr ld-elf.so.1 1 ,
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.Xr dlopen 3 ,
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.Xr elf 5
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.Sh HISTORY
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The
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.Nm
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function first appeared in
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.Fx 7.0 .
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