public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
* [RFC][PATCH v13 0/9] Implementation of RTLD_SHARED for dlmopen
@ 2021-09-29 16:26 Vivek Das Mohapatra
  2021-09-29 16:26 ` [RFC][PATCH v13 1/9] Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745) Vivek Das Mohapatra
                   ` (10 more replies)
  0 siblings, 11 replies; 14+ messages in thread
From: Vivek Das Mohapatra @ 2021-09-29 16:26 UTC (permalink / raw)
  To: libc-alpha

This is a revision of a previous patchset that I posted here
regarding https://sourceware.org/bugzilla/show_bug.cgi?id=22745 

Introduction:

=======================================================================
  As discussed in the URL above dlmopen requires a mechanism for
  [optionally] sharing some objects between more than one namespace.

  The following patchset provides 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.

  In addition a new ELF dynamic section and flag are introduced which
  indicate that the DSO in question should be shared between namespaces
  by default, and the core libc DSOs are tagged as such by default.

  This patch series should address all the comments received on the
  earlier (v1-v12) series.

=======================================================================

Changes from v12:

 - Added NEWS entry.

 - Updated patch series to glibc 2.35 as a base.

 - The following DSOs no longer have the new flag since they are stubs:
   {htl,nptl}/libpthread, dlfcn/libdl, login/libutil, resolv/libanl

Changes from v11:

 - If a DSO is required in a non-base namespace because it is mentioned
   in a DT_NEEDED entry and it is itself flagged DF_GNU_1_UNIQUE then
   a proxy is generated for it.

 - Relocations via non-base namespace proxies work reliably (some code
   paths did not do the address calculation relative to the DSO base
   correctly when a proxy was involved).

 - Tests extended cover the above two scenarios.

Changes from v10:

 - A segfault in a dlmopen error pathway (which does not seem to have existed
   when v10 was applied to the then-HEAD commit) has been fixed.

 - The fallback mechanism for adding DT_GNU_FLAGS_1 sections to the required
   binaries has had some infrastructure moved to the elf/ directory

 - The runstatedir setting introduced by recent autoconf has been omitted from
   the patchset as it is not relevant to this feature.

 - libpthread no longer tagged DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE.
   (with both -z unique supporting linkers and if the .os hack is
   used to add the new flag - this was inconsistent before).

Not changed:

 - There is still some diagnostic info in the config.log when the linker
   layout is acceptable but -z unique is not yet supported. I believe this
   _is_ useful diagnostic information as a developer might otherwise wonder
   why the vanilla linker was being rejected when its layout output seemed
   fine.

I have not yet implemented, but plan to address once this series is
accepted/acceptable:

 - dl_iterate_ns_phdr (cf dl_iterate_phdr but taking a namespace argument)

 - Check RTLD_GLOBAL interacts properly and unsurprisingly with RTLD_SHARED.

Vivek Das Mohapatra (9):
  Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745)
  Abstract loaded-DSO search code into a helper function
  Use the new DSO finder helper function
  Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745)
  Implement dlmopen RTLD_SHARED flag (bug 22745)
  Add dlmopen / RTLD_SHARED tests
  Restore separate libc loading for the TLS/namespace storage test
  Drop DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE from merged libraries
  NEWS for RTLD_SHARED, RTLD_ISOLATE & DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE

 Makeconfig                           |   3 +
 Makerules                            |  18 +-
 NEWS                                 |  17 +
 bits/dlfcn.h                         |  10 +
 config.make.in                       |   1 +
 configure                            |  42 +-
 configure.ac                         |  31 +-
 dlfcn/Makefile                       |   1 +
 elf/Makefile                         | 109 +++-
 elf/dl-close.c                       |  43 +-
 elf/dl-deps.c                        |  17 +
 elf/dl-fini.c                        |   6 +-
 elf/dl-init.c                        |   4 +-
 elf/dl-load.c                        | 223 ++++++-
 elf/dl-lookup.c                      |  26 +-
 elf/dl-object.c                      |  78 +++
 elf/dl-open.c                        | 128 +++-
 elf/dl-sym.c                         |  14 +
 elf/dynamic-notes.c                  |   4 +
 elf/elf.h                            |   7 +-
 elf/get-dynamic-info.h               |  12 +
 elf/rtld.c                           |   2 +-
 elf/tst-dlmopen-auditmod.c           |  23 +
 elf/tst-dlmopen-common.h             |  33 +
 elf/tst-dlmopen-main.h               | 879 +++++++++++++++++++++++++++
 elf/tst-dlmopen-modules.h            |  21 +
 elf/tst-dlmopen-rtld-audit-shared1.c |   8 +
 elf/tst-dlmopen-rtld-audit-shared2.c |   8 +
 elf/tst-dlmopen-rtld-audit-shared3.c |   7 +
 elf/tst-dlmopen-rtld-audit-shared4.c |   8 +
 elf/tst-dlmopen-rtld-audit-shared5.c |   8 +
 elf/tst-dlmopen-rtld-audit-shared6.c |   8 +
 elf/tst-dlmopen-rtld-audit-unique1.c |   7 +
 elf/tst-dlmopen-rtld-audit-unique2.c |   7 +
 elf/tst-dlmopen-rtld-audit-unique3.c |   7 +
 elf/tst-dlmopen-rtld-audit-unique4.c |   7 +
 elf/tst-dlmopen-rtld-audit-unique5.c |   7 +
 elf/tst-dlmopen-rtld-audit-unique6.c |   7 +
 elf/tst-dlmopen-rtld-shared1.c       |   7 +
 elf/tst-dlmopen-rtld-shared1.h       |  64 ++
 elf/tst-dlmopen-rtld-shared2.c       |   7 +
 elf/tst-dlmopen-rtld-shared2.h       |  66 ++
 elf/tst-dlmopen-rtld-shared3.c       |   7 +
 elf/tst-dlmopen-rtld-shared3.h       |  43 ++
 elf/tst-dlmopen-rtld-shared4.c       |   7 +
 elf/tst-dlmopen-rtld-shared4.h       |  14 +
 elf/tst-dlmopen-rtld-shared5.c       |   7 +
 elf/tst-dlmopen-rtld-shared5.h       |  25 +
 elf/tst-dlmopen-rtld-shared6.c       |   7 +
 elf/tst-dlmopen-rtld-shared6.h       |  36 ++
 elf/tst-dlmopen-rtld-unique1.c       |   7 +
 elf/tst-dlmopen-rtld-unique1.h       |  86 +++
 elf/tst-dlmopen-rtld-unique2.c       |   7 +
 elf/tst-dlmopen-rtld-unique2.h       |  25 +
 elf/tst-dlmopen-rtld-unique3.c       |   7 +
 elf/tst-dlmopen-rtld-unique3.h       |  13 +
 elf/tst-dlmopen-rtld-unique4.c       |   7 +
 elf/tst-dlmopen-rtld-unique4.h       |  14 +
 elf/tst-dlmopen-rtld-unique5.c       |   7 +
 elf/tst-dlmopen-rtld-unique5.h       |  58 ++
 elf/tst-dlmopen-rtld-unique6.c       |   7 +
 elf/tst-dlmopen-rtld-unique6.h       |  51 ++
 elf/tst-dlmopen-sharedmod-norm.c     |  34 ++
 elf/tst-dlmopen-sharedmod-uniq.c     |  33 +
 elf/tst-dlmopen-std-do-test.c        |  12 +
 elf/tst-tls-ie-dlmopen.c             |   4 +-
 extra-lib.mk                         |  28 +
 htl/Makefile                         |   2 +
 iconvdata/Makefile                   |   3 +
 iconvdata/extra-module.mk            |   4 +
 include/elf.h                        |   2 +
 include/link.h                       |   7 +-
 login/Makefile                       |   1 +
 nptl/Makefile                        |   5 +-
 resolv/Makefile                      |   2 +
 sysdeps/generic/ldsodefs.h           |  11 +
 sysdeps/mips/bits/dlfcn.h            |  10 +
 77 files changed, 2501 insertions(+), 77 deletions(-)
 create mode 100644 elf/dynamic-notes.c
 create mode 100644 elf/tst-dlmopen-auditmod.c
 create mode 100644 elf/tst-dlmopen-common.h
 create mode 100644 elf/tst-dlmopen-main.h
 create mode 100644 elf/tst-dlmopen-modules.h
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared1.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared2.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared3.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared4.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared5.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-shared6.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique1.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique2.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique3.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique4.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique5.c
 create mode 100644 elf/tst-dlmopen-rtld-audit-unique6.c
 create mode 100644 elf/tst-dlmopen-rtld-shared1.c
 create mode 100644 elf/tst-dlmopen-rtld-shared1.h
 create mode 100644 elf/tst-dlmopen-rtld-shared2.c
 create mode 100644 elf/tst-dlmopen-rtld-shared2.h
 create mode 100644 elf/tst-dlmopen-rtld-shared3.c
 create mode 100644 elf/tst-dlmopen-rtld-shared3.h
 create mode 100644 elf/tst-dlmopen-rtld-shared4.c
 create mode 100644 elf/tst-dlmopen-rtld-shared4.h
 create mode 100644 elf/tst-dlmopen-rtld-shared5.c
 create mode 100644 elf/tst-dlmopen-rtld-shared5.h
 create mode 100644 elf/tst-dlmopen-rtld-shared6.c
 create mode 100644 elf/tst-dlmopen-rtld-shared6.h
 create mode 100644 elf/tst-dlmopen-rtld-unique1.c
 create mode 100644 elf/tst-dlmopen-rtld-unique1.h
 create mode 100644 elf/tst-dlmopen-rtld-unique2.c
 create mode 100644 elf/tst-dlmopen-rtld-unique2.h
 create mode 100644 elf/tst-dlmopen-rtld-unique3.c
 create mode 100644 elf/tst-dlmopen-rtld-unique3.h
 create mode 100644 elf/tst-dlmopen-rtld-unique4.c
 create mode 100644 elf/tst-dlmopen-rtld-unique4.h
 create mode 100644 elf/tst-dlmopen-rtld-unique5.c
 create mode 100644 elf/tst-dlmopen-rtld-unique5.h
 create mode 100644 elf/tst-dlmopen-rtld-unique6.c
 create mode 100644 elf/tst-dlmopen-rtld-unique6.h
 create mode 100644 elf/tst-dlmopen-sharedmod-norm.c
 create mode 100644 elf/tst-dlmopen-sharedmod-uniq.c
 create mode 100644 elf/tst-dlmopen-std-do-test.c

-- 
2.20.1


^ permalink raw reply	[flat|nested] 14+ messages in thread

end of thread, other threads:[~2021-09-29 19:30 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-29 16:26 [RFC][PATCH v13 0/9] Implementation of RTLD_SHARED for dlmopen Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 1/9] Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745) Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 2/9] Abstract loaded-DSO search code into a helper function Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 3/9] Use the new DSO finder " Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 4/9] Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 5/9] Implement dlmopen RTLD_SHARED flag " Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 6/9] Add dlmopen / RTLD_SHARED tests Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 7/9] Restore separate libc loading for the TLS/namespace storage test Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 8/9] Drop DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE from merged libraries Vivek Das Mohapatra
2021-09-29 16:26 ` [RFC][PATCH v13 9/9] NEWS for RTLD_SHARED, RTLD_ISOLATE & DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE Vivek Das Mohapatra
2021-09-29 16:43 ` [RFC][PATCH v13 0/9] Implementation of RTLD_SHARED for dlmopen Joseph Myers
2021-09-29 17:32   ` Vivek Das Mohapatra
2021-09-29 18:33 ` Adhemerval Zanella
2021-09-29 19:30   ` Vivek Das Mohapatra

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).