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diff --git a/open_issues/libpthread_addon.mdwn b/open_issues/libpthread_addon.mdwn new file mode 100644 index 00000000..65c8ab68 --- /dev/null +++ b/open_issues/libpthread_addon.mdwn @@ -0,0 +1,144 @@ +[[!meta copyright="Copyright © 2012 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="libpthread as glibc addon"]] + +[[!tag open_issue_glibc open_issue_libpthread]] + +This page lists all the notes, issues, etc, only about compiling libpthread +as addon for glibc, *not* for general libpthread issues. + +# Building + +To build libpthread as glibc addon, copy libpthread inside the glibc tree, +and then tell glibc's configure to use it: + + $ cp /path/to/libpthread libpthread + $ ./configure [...] --enable-add-ons=[...],libpthread + +Currently, it is build like that in Debian since eglibc 2.13-31. + +# Issues and notes + +### Compatibility with glibc >= 2.16 + +[[!message-id "201211161520.32894.toscano.pino@tiscali.it"]] + +### `bits/` headers not used + +Recompiling glibc (e.g. on a Debian system) and running the +`check-local-headers` test, `check-local-headers.out` shows: + + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/pthread.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/thread-attr.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/mutex-attr.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/mutex.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/condition-attr.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/condition.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/rwlock-attr.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/rwlock.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/barrier-attr.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/barrier.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/thread-specific.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/once.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/cancelation.h + *** $(common-objpfx)elf/tst-thrlock.o: uses /usr/include/i386-gnu/bits/pthread-np.h + +This happens because these headers are in the `bits/` subdirectory in +`sysdeps/generic` -- a `generic` sysdep is used only for the top-level +`sysdeps` directory in glibc. + +### Use of hurd's libihash + +libpthread makes use of the ihash hurd library, as also glibc's +`check-local-headers` test shows: + + *** $(common-objpfx)libpthread/pt-alloc.o: uses /usr/include/hurd/ihash.h + +### Executable stack + +Running glibc's `check-execstack` test gives in `check-execstack.out`: + + $BUILDDIR/libpthread/libpthread.so.phdr: *** executable stack signaled + +### Extra PLT references + +Running glibc's `check-localplt` test gives in `check-localplt.out`: + + Extra PLT reference: libpthread.so: pthread_detach + Extra PLT reference: libpthread.so: pthread_mutex_lock + Extra PLT reference: libpthread.so: pthread_mutexattr_settype + Extra PLT reference: libpthread.so: pthread_rwlock_rdlock + Extra PLT reference: libpthread.so: _pthread_spin_lock + Extra PLT reference: libpthread.so: pthread_attr_setstacksize + Extra PLT reference: libpthread.so: pthread_attr_getstacksize + Extra PLT reference: libpthread.so: pthread_attr_getstackaddr + Extra PLT reference: libpthread.so: pthread_attr_setstackaddr + Extra PLT reference: libpthread.so: pthread_exit + Extra PLT reference: libpthread.so: pthread_getspecific + Extra PLT reference: libpthread.so: __mutex_lock_solid + Extra PLT reference: libpthread.so: pthread_mutex_unlock + Extra PLT reference: libpthread.so: pthread_setcanceltype + Extra PLT reference: libpthread.so: pthread_key_create + Extra PLT reference: libpthread.so: pthread_cond_wait + Extra PLT reference: libpthread.so: pthread_rwlock_wrlock + Extra PLT reference: libpthread.so: pthread_once + Extra PLT reference: libpthread.so: pthread_cond_broadcast + Extra PLT reference: libpthread.so: pthread_setspecific + Extra PLT reference: libpthread.so: __pthread_get_cleanup_stack + Extra PLT reference: libpthread.so: pthread_rwlock_unlock + Extra PLT reference: libpthread.so: pthread_create + Extra PLT reference: libpthread.so: pthread_mutex_init + Extra PLT reference: libpthread.so: pthread_mutexattr_init + Extra PLT reference: libpthread.so: __mutex_unlock_solid + Extra PLT reference: libpthread.so: pthread_mutexattr_destroy + Extra PLT reference: libpthread.so: pthread_setcancelstate + +### `pthread` sysdep + +glibc provides a `pthread` sysdep (`sysdeps/pthread`) with pthread-based +implementations of most of the `aio_*` and `lio_*` functions. + +[[!message-id "201209302353.51055.toscano.pino@tiscali.it"]] + +The above patches allows also to cleanly set the libpthread string version, +returned e.g. for the `_CS_GNU_LIBPTHREAD_VERSION` value of `confstr`. + +About the glibc aio tests, they would all compile and work, except: + + - `tst-aio` -- failing + - `tst-aio9`, `tst-aio10` -- timing out + +### `bits/posix_opt.h` + +`bits/posix_opt.h` is the glibc header defining the various +supported/unsupported `_POSIX_*` defines (e.g. `_POSIX_THREADS`, etc). + +Currently, glibc's `sysdeps/mach/hurd/bits/posix_opt.h` is patched in Debian +to add all the defines advertizing thread-related support. +An idea to avoid this would be to follow what is done in NPTL, and do the +following: + + - in glibc: leave `sysdeps/mach/hurd/bits/posix_opt.h` with *no* +thread-related macros at all. + + - in libpthread: provide `sysdeps/mach/hurd/bits/posix_opt.h` which would +be a copy of glibc's `sysdeps/mach/hurd/bits/posix_opt.h` with also the thread +macros. + +This approach would have the drawback that changes in the glibc header must be +mirrored also in the libpthread version, but with the advantage that defines +according to supported features in libpthread can be added in libpthread's own +version (and glibc would pick it automatically). + +### Tests + +The (few) existing tests are not built (thus neither run) just like other tests +in glibc. |