Commit Graph

16 Commits

Author SHA1 Message Date
Konstantin Belousov
c8da4f07d7 Allow the NULL, RTLD_SELF and RTLD_NEXT handles to work with dlfunc(3).
dlfunc() called dlsym() to do the work, and dlsym() determines the dso
that originating the call by the return address. Due to this, dlfunc()
operated as if the caller is always the libc.

To fix this, move the dlfunc() to rtld, where it can call the internal
implementation of dlsym, and still correctly fetch return address.
Provide usual weak stub for the symbol from libc for static binaries.
dlfunc is put to FBSD_1.0 symver namespace in the ld.so export to
override dlfunc@FBSD_1.0 weak symbol, exported by libc.

Reported, analyzed and tested by:	Tijl Coosemans <tijl ulyssis org>
PR: standards/133339
Reviewed by:	kan
2009-04-03 19:17:23 +00:00
Konstantin Belousov
cb5c4b10ba Add two rtld exported symbols, _rtld_atfork_pre and _rtld_atfork_post.
Threading library calls _pre before the fork, allowing the rtld to
lock itself to ensure that other threads of the process are out of
dynamic linker. _post releases the locks.

This allows the rtld to have consistent state in the child. Although
child may legitimately call only async-safe functions, the call may
need plt relocation resolution, and this requires working rtld.

Reported and debugging help by:	rink
Reviewed by:	kan, davidxu
MFC after:	1 month (anyway, not before 7.1 is out)
2008-11-27 11:27:59 +00:00
Alexander Kabaev
832a21869c Add stub for dl_iterate_phdr. 2007-04-03 18:35:20 +00:00
Alexander Kabaev
0eb88f2029 Implement ELF symbol versioning using GNU semantics. This code aims
to be compatible with symbol versioning support as implemented by
GNU libc and documented by http://people.redhat.com/~drepper/symbol-versioning
and LSB 3.0.

Implement dlvsym() function to allow lookups for a specific version of
a given symbol.
2005-12-18 19:43:33 +00:00
Mark Murray
16fc3635f7 Make NULL a (void*)0 whereever possible, and fix the warnings(-Werror)
that this provokes. "Wherever possible" means "In the kernel OR NOT
C++" (implying C).

There are places where (void *) pointers are not valid, such as for
function pointers, but in the special case of (void *)0, agreement
settles on it being OK.

Most of the fixes were NULL where an integer zero was needed; many
of the fixes were NULL where ascii <nul> ('\0') was needed, and a
few were just "other".

Tested on: i386 sparc64
2004-03-05 08:10:19 +00:00
Alexander Kabaev
8c22e2f77b Add an stub for _rtld_thread_init. This is a part I missed in
my last commit.

Approved by:	re (scottl)
2003-05-30 00:58:37 +00:00
Alexander Kabaev
42d206e975 Implement dlinfo() function.
Introdice RTLD_SELF special handle and properly process it within
dlsym() and dlinfo() functions.

The intention is to improve our compatibility with Solaris and
to make a Java port easier.

Partially submitted by:	phantom
2003-02-13 17:47:44 +00:00
Peter Wemm
66422f5b7a Initiate deorbit burn for the i386-only a.out related support. Moves are
under way to move the remnants of the a.out toolchain to ports.  As the
comment in src/Makefile said, this stuff is deprecated and one should not
expect this to remain beyond 4.0-REL.  It has already lasted WAY beyond
that.

Notable exceptions:
gcc - I have not touched the a.out generation stuff there.
ldd/ldconfig - still have some code to interface with a.out rtld.
old as/ld/etc - I have not removed these yet, pending their move to ports.
some includes - necessary for ldd/ldconfig for now.

Tested on: i386 (extensively), alpha
2002-09-17 01:49:00 +00:00
Mike Barcroft
a4a96c8166 Add `restrict' type-qualifier. 2002-09-11 05:05:48 +00:00
David E. O'Brien
ea8d448a92 Fix SCM ID's. 2002-02-01 00:57:29 +00:00
John Polstra
d3980376e8 Add a new function dllockinit() for registering thread locking
functions to be used by the dynamic linker.  This can be called by
threads packages at start-up time.  I will add the call to libc_r
soon.

Also add a default locking method that is used up until dllockinit()
is called.  The default method works by blocking SIGVTALRM, SIGPROF,
and SIGALRM in critical sections.  It is based on the observation
that most user-space threads packages implement thread preemption
with one of these signals (usually SIGVTALRM).

The dynamic linker has never been reentrant, but it became less
reentrant in revision 1.34 of "src/libexec/rtld-elf/rtld.c".
Starting with that revision, multiple threads each doing lazy
binding could interfere with each other.  The usual symptom was
that a symbol was falsely reported as undefined at start-up time.
It was rare but not unseen.  This commit fixes it.
1999-12-27 04:44:04 +00:00
Peter Wemm
7f3dea244c $Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00
John Polstra
6d30b16752 Back out my change from 6 April PDT that added a new dlversion()
function.  It was an ill-considered feature.  It didn't solve the
problem I wanted it to solve.   And it added Yet Another Version
Number that would have to be maintained at every release point.
I'm nuking it now before anybody grows too fond of it.
1999-04-22 01:54:38 +00:00
John Polstra
14f5fa0596 Add a new function dlversion() which returns the version number of
the dynamic linker in the same form as __FreeBSD_version.  This is
mainly intended for checking the dynamic linker version during a make
world.
1999-04-07 02:43:11 +00:00
John Polstra
1ab7c6cc77 Add support for ELF.
Switch to ANSI-style function definitions.
1998-03-07 19:57:05 +00:00
John Polstra
645c4be38a Move the trampolines for dlopen and related functions from crt0.o
into libc.  This reduces the size of every dynamically linked
executable by 248 bytes, and it reduces the size of static executables
by a lesser amount.  It also eliminates some global namespace
pollution.

With this change in place, the source for dlfcn.h should probably
be moved to "/usr/src/include".  I'll save that for another day.

Compatibility note:  Programs which use dlopen, if compiled on
systems with this change, will not run on systems with a libc from
prior to this change.  Very few programs use dlopen, so I think
that is OK.
1998-02-09 06:05:25 +00:00