From: "Vivek Das Mohapatra" <vivek@collabora.com>
To: libc-alpha@sourceware.org
Subject: [RFC][PATCH v1 0/5] Proof-of-Concept implementation of RTLD_SHARED for dlmopen
Date: Wed, 16 May 2018 17:11:00 -0000 [thread overview]
Message-ID: <20180516171124.24962-1-vivek@collabora.com> (raw)
As discussed in https://sourceware.org/bugzilla/show_bug.cgi?id=22745
dlmopen requires a mechanism for [optionally] sharing some objects
between more than one namespace.
The following patchset attempts an implementation for this: If an object
is loaded with the new RTLD_SHARED flag we instead ensure that a "master"
copy exists (and is flagged as no-delete) in the main namespace and a
thin wrapper or clone is placed in the target namespace.
I have attached the test program(s) I am using to the bug above.
It is not intended as a final implementation but I wanted to check
that the basic approach is acceptable/workable.
If it is, then I plan to extend the patchset as follows:
- dlmopen will implicitly apply RTLD_SHARED to the libc/libpthread group
- The user will be able to request that this sharing _not_ occur
by passing a different flag to dlmopen (name TBD)
- LD_AUDIT paths will not apply this implict sharing rule, so audit libraries
will continue to be completely isolated.
If it isn't, then I guess it's back to the drawing board (but reasons why
it isn't acceptable/workable would be appreciated so I can figure out how
to do it right).
Vivek Das Mohapatra (5):
bits/dlfcn.h: Declare and describe the dlmopen RTLD_SHARED flag
include/link.h: Update the link_map struct to allow clones
elf/dl-object.c: Implement a helper function to clone link_map entries
elf/dl-load.c, elf-dl-open.c: Implement RTLD_SHARED dlmopen cloning
elf/dl-fini.c: Handle cloned link_map entries in the shutdown path
bits/dlfcn.h | 7 +++++
elf/dl-fini.c | 50 ++++++++++++++++++++++++++++++
elf/dl-load.c | 34 ++++++++++++++++++++
elf/dl-object.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++
elf/dl-open.c | 31 +++++++++++++++++--
include/link.h | 6 ++--
sysdeps/generic/ldsodefs.h | 6 ++++
7 files changed, 207 insertions(+), 4 deletions(-)
--
2.11.0
next reply other threads:[~2018-05-16 17:11 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 17:11 Vivek Das Mohapatra [this message]
2018-05-16 17:11 ` [RFC][PATCH v1 2/5] include/link.h: Update the link_map struct to allow clones Vivek Das Mohapatra
2018-05-18 18:47 ` Carlos O'Donell
2018-05-18 19:32 ` Vivek Das Mohapatra
2018-05-16 17:11 ` [RFC][PATCH v1 3/5] elf/dl-object.c: Implement a helper function to clone link_map entries Vivek Das Mohapatra
2018-05-20 2:48 ` Carlos O'Donell
2018-05-16 17:11 ` [RFC][PATCH v1 1/5] bits/dlfcn.h: Declare and describe the dlmopen RTLD_SHARED flag Vivek Das Mohapatra
2018-05-18 18:37 ` Carlos O'Donell
2018-05-18 19:31 ` Vivek Das Mohapatra
2018-05-16 17:11 ` [RFC][PATCH v1 5/5] elf/dl-fini.c: Handle cloned link_map entries in the shutdown path Vivek Das Mohapatra
2018-05-18 19:09 ` Carlos O'Donell
2018-05-18 19:25 ` Vivek Das Mohapatra
2018-05-16 17:19 ` [RFC][PATCH v1 4/5] elf/dl-load.c, elf-dl-open.c: Implement RTLD_SHARED dlmopen cloning Vivek Das Mohapatra
2018-05-18 19:02 ` Carlos O'Donell
2018-05-18 19:20 ` Vivek Das Mohapatra
2018-05-16 19:30 ` [RFC][PATCH v1 0/5] Proof-of-Concept implementation of RTLD_SHARED for dlmopen Joseph Myers
2018-05-16 19:39 ` Vivek Das Mohapatra
2018-05-16 19:44 ` Joseph Myers
2018-05-16 19:46 ` Vivek Das Mohapatra
2018-05-16 20:03 ` Vivek Das Mohapatra
2018-05-16 19:44 ` Carlos O'Donell
2018-05-16 19:46 ` Vivek Das Mohapatra
2018-05-16 20:39 ` Carlos O'Donell
2018-05-18 11:46 ` Vivek Das Mohapatra
2018-05-18 18:16 ` Carlos O'Donell
2018-05-18 18:30 ` Carlos O'Donell
2018-05-18 19:06 ` Vivek Das Mohapatra
2018-05-18 19:26 ` Carlos O'Donell
2018-05-18 19:53 ` Vivek Das Mohapatra
2018-05-18 20:03 ` Carlos O'Donell
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