The implementation is based on scalar Chacha20 with per-thread cache.
It uses getrandom or /dev/urandom as fallback to get the initial entropy,
and reseeds the internal state on every 16MB of consumed buffer.
To improve performance and lower memory consumption the per-thread cache
is allocated lazily on first arc4random functions call, and if the
memory allocation fails getentropy or /dev/urandom is used as fallback.
The cache is also cleared on thread exit iff it was initialized (so if
arc4random is not called it is not touched).
Although it is lock-free, arc4random is still not async-signal-safe
(the per thread state is not updated atomically).
The ChaCha20 implementation is based on RFC8439 [1], omitting the final
XOR of the keystream with the plaintext because the plaintext is a
stream of zeros. This strategy is similar to what OpenBSD arc4random
does.
The arc4random_uniform is based on previous work by Florian Weimer,
where the algorithm is based on Jérémie Lumbroso paper Optimal Discrete
Uniform Generation from Coin Flips, and Applications (2013) [2], who
credits Donald E. Knuth and Andrew C. Yao, The complexity of nonuniform
random number generation (1976), for solving the general case.
The main advantage of this method is the that the unit of randomness is not
the uniform random variable (uint32_t), but a random bit. It optimizes the
internal buffer sampling by initially consuming a 32-bit random variable
and then sampling byte per byte. Depending of the upper bound requested,
it might lead to better CPU utilization.
Checked on x86_64-linux-gnu, aarch64-linux, and powerpc64le-linux-gnu.
Co-authored-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>
[1] https://datatracker.ietf.org/doc/html/rfc8439
[2] https://arxiv.org/pdf/1304.1916.pdf
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date. Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.
Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions. These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.
The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively. These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:
https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dchttps://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
It enables and disables cancellation with pthread_setcancelstate
before calling the waitpid. It simplifies the waitpid implementation
for architectures that do not provide either __NR_waitpid or
__NR_wait4.
Checked on x86_64-linux-gnu.
This is in preparation for changes in the dynamic linker so that
pread() is used instead of lseek()+read().
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This patch fixes the OFD ("file private") locks for architectures that
support non-LFS flock definition (__USE_FILE_OFFSET64 not defined). The
issue in this case is both F_OFD_{GETLK,SETLK,SETLKW} and
F_{SET,GET}L{W}K64 expects a flock64 argument and when using old
F_OFD_* flags with a non LFS flock argument the kernel might interpret
the underlying data wrongly. Kernel idea originally was to avoid using
such flags in non-LFS syscall, but since GLIBC uses fcntl with LFS
semantic as default it is possible to provide the functionality and
avoid the bogus struct kernel passing by adjusting the struct manually
for the required flags.
The idea follows other LFS interfaces that provide two symbols:
1. A new LFS fcntl64 is added on default ABI with the usual macros to
select it for FILE_OFFSET_BITS=64.
2. The Linux non-LFS fcntl use a stack allocated struct flock64 for
F_OFD_{GETLK,SETLK,SETLKW} copy the results on the user provided
struct.
3. Keep a compat symbol with old broken semantic for architectures
that do not define __OFF_T_MATCHES_OFF64_T.
So for architectures which defines __USE_FILE_OFFSET64, fcntl64 will
aliased to fcntl and no adjustment would be required. So to actually
use F_OFD_* with LFS support the source must be built with LFS support
(_FILE_OFFSET_BITS=64).
Also F_OFD_SETLKW command is handled a cancellation point, as for
F_SETLKW{64}.
Checked on x86_64-linux-gnu and i686-linux-gnu.
[BZ #20251]
* NEWS: Mention fcntl64 addition.
* csu/check_fds.c: Replace __fcntl_nocancel by __fcntl64_nocancel.
* login/utmp_file.c: Likewise.
* sysdeps/posix/fdopendir.c: Likewise.
* sysdeps/posix/opendir.c: Likewise.
* sysdeps/unix/pt-fcntl.c: Likewise.
* include/fcntl.h (__libc_fcntl64, __fcntl64,
__fcntl64_nocancel_adjusted): New prototype.
(__fcntl_nocancel_adjusted): Remove prototype.
* io/Makefile (routines): Add fcntl64.
(CFLAGS-fcntl64.c): New rule.
* io/Versions [GLIBC_2.28] (fcntl64): New symbol.
[GLIBC_PRIVATE] (__libc_fcntl): Rename to __libc_fcntl64.
* io/fcntl.h (fcntl64): Add prototype and redirect if
__USE_FILE_OFFSET64 is defined.
* io/fcntl64.c: New file.
* manual/llio.text: Add a note for which commands fcntl acts a
cancellation point.
* nptl/Makefile (CFLAGS-fcntl64.c): New rule.
* sysdeps/mach/hurd/fcntl.c: Alias fcntl to fcntl64 symbols.
* sysdeps/mach/hurd/i386/libc.abilist [GLIBC_2.28] (fcntl, fcntl64):
New symbols.
* sysdeps/unix/sysv/linux/fcntl.c (__libc_fcntl): Fix F_GETLK64,
F_OFD_GETLK, F_SETLK64, F_SETLKW64, F_OFD_SETLK, and F_OFD_SETLKW for
non-LFS case.
* sysdeps/unix/sysv/linux/fcntl64.c: New file.
* sysdeps/unix/sysv/linux/fcntl_nocancel.c (__fcntl_nocancel): Rename
to __fcntl64_nocancel.
(__fcntl_nocancel_adjusted): Rename to __fcntl64_nocancel_adjusted.
* sysdeps/unix/sysv/linux/not-cancel.h (__fcntl_nocancel): Rename
to __fcntl64_nocancel.
* sysdeps/unix/sysv/linux/tst-ofdlocks.c: New file.
* sysdeps/unix/sysv/linux/tst-ofdlocks-compat.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile (tests): Add tst-ofdlocks.
(tests-internal): Add tst-ofdlocks-compat.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist [GLIBC_2.28]
(fcntl64): New symbol.
* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.28] (fcntl,
fcntl64): Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilis: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.
The NO_CANCELLATION macro is used currently on generic headers to
define non cancellable syscalls and on Linux fcntl to implement the non
cancellable variation. Former should be single-handled by not-cancel.h
header and former could be simplified build both cancellable and non
cancellable for default objects and alias the non-cancellable to default
one for rtld ones (since Linux already support cancellation as default).
This patch thus removes the NO_CANCELLATION macro and its usage. The
generic non cancellable fcntl is route to internal fcntl.
Checked on x86_64-linux-gnu and i686-linux-gnu. Also checked with
a build again major ABIs.
* sysdeps/generic/not-cancel.h (NO_CANCELLATION): Remove macro.
* sysdeps/unix/sysv/linux/aarch64/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/alpha/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/arm/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/hppa/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/i386/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/ia64/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/m68k/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/microblaze/sysdep-cancel.h
(NO_CANCELLATION): Likewise.
* sysdeps/unix/sysv/linux/mips/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/nios2/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/sysdep-cancel.h
(NO_CANCELLATION): Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/sysdep-cancel.h
(NO_CANCELLATION): Likewise.
* sysdeps/unix/sysv/linux/sh/sysdep-cancel.h (NO_CANCELLATION):
Likewise
* sysdeps/unix/sysv/linux/sparc/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/tile/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h (NO_CANCELLATION):
Likewise.
* sysdeps/unix/sysv/linux/not-cancel.h (__fcntl_nocancel): Add
hidden prototype.
* sysdeps/unix/sysv/linux/fcntl.c (__fcntl_nocancel): Define only
for !IS_IN (rtld) and remove NO_CANCELLATION usage.
This patch consolidate the remaning non cancellable syscall definitions
on not-cancel.h header. They are:
* __fcntl_nocancel: Moved from fcntl.h to not-cancel.h.
* __sigsuspend_nocancel: Removed since 988f991b50 it is not used or
defined anymore.
* __nanosleep_nocancel: Removed since 6f33fd046b it is defined on
not-cancel.h.
Now all non-cancellable syscall definition are defined on not-cancel
(the only exceptions is the stdio symbol __fxprintf_nocancel which
uses non cancellable open and it is used on getopt implementation).
Checked on x86_64-linux-gnu and with build-many-glibc.py.
* include/fcntl.h (__fcntl_nocancel): Remove definition.
* include/signal.h (__sigsuspend_nocancel): Likewise.
* include/time.h (__nanosleep_nocancel): Likewise.
* sysdeps/generic/not-cancel.h (__fcntl_nocancel): New macro.
* login/utmp_file.c: Include non cancellable syscall header.
* sysdeps/unix/sysv/linux/not-cancel.h (__fcntl_nocancel): New
prototype.
There is no current internal usage for non cancellable sigsuspend calls.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* sysdeps/generic/not-cancel.h (sigsuspend_not_cancel): remove
macro.
* sysdeps/mach/hurd/sigsuspend.c (sigsuspend_not_cancel): remove
alias.
* sysdeps/unix/sysv/linux/not-cancel.h (sigsuspend_not_cancel):
likewise.
This patch consolidates all the non cancellable nanosleep calls to use
the __nanosleep_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Replace
nanosleep_not_cancel with __nanosleep_nocancel.
* sysdeps/generic/not-cancel.h (nanosleep_not_cancel): Remove macro.
(__nanosleep_nocancel): New macro.
* sysdeps/unix/sysv/linux/nanosleep.c (__nanosleep_nocancel): New
function.
* sysdeps/unix/sysv/linux/not-cancel.h (nanosleep_not_cancel): Remove
macro.
(__nanosleep_nocancel): New prototype.
This patch consolidates all the non cancellable pause calls to use
the __pause_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* nptl/pthread_mutex_lock.c (__pthread_mutex_lock_full): Replace
pause_not_cancel with __pause_nocancel.
* sysdeps/generic/not-cancel.h (pause_not_cancel): Remove macro.
(__pause_nocancel): New macro.
* sysdeps/unix/sysv/linux/not-cancel.h (pause_not_cancel): Remove
macro.
(__pause_nocancel): New prototype.
* sysdeps/unix/sysv/linux/pause.c (__pause_nocancel): New function.
This patch consolidates all the non cancellable waitpid calls to use
the __waitpid_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* libio/ioopen.c (_IO_waitpid): Replace waitpid_not_cancel with
__waitpid_nocancel.
* sysdeps/generic/not-cancel.h (waitpid_not_cancel): Remove macro.
(__waitpid_nocancel): New macro.
* sysdeps/unix/sysv/linux/not-cancel.h (waitpid_not_cancel): Remove
macro.
(__waitpid_nocancel): Replace macro with a function.
* sysdeps/unix/sysv/linux/waitpid.c (__waitpid_nocancel): New
function.
This patch consolidates all the non cancellable fcntl calls to use
the __fcntl_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Since its prototype is already defined at internal fcntl.h header, it
is removed from not-cancel.h one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* login/utmp_file.c (timeout_handler): Replace fcntl_not_cancel with
__fcntl_nocancel.
* sysdeps/generic/not-cancel.h (fcntl_not_cancel): Remove macro.
* sysdeps/unix/sysv/linux/not-cancel.h (fcntl_not_cancel): Likewise.
This patch consolidates all the non cancellable writev calls to use
the __writev_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* gmon/gmon.c (write_hist): Replace writev_not_cancel_no_status with
__writev_nocancel_nostatus.
(write_call_graph): Likewise.
(write_bb_counts): Likewise.
* resolv/herror.c (herror): Likewise.
* sysdeps/generic/not-cancel.h (writev_not_cancel_no_status): Remove
macro.
(__writev_nocancel_nostatus): New macro.
* sysdeps/unix/sysv/linux/not-cancel.h (writev_not_cancel_no_status):
Remove macro.
(__writev_nocancel_nostatus): New function.
This patch consolidates all the non cancellable openat{64} calls to use
the __openat{64}_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* sysdeps/generic/not-cancel.h (openat_not_cancel): Remove macro.
(openat_not_cancel_3): Likewise.
(openat64_not_cancel_3): Likewise).
(openat_not_cancel_3): Likewise).
* sysdeps/unix/sysv/linux/not-cancel.h (openat_not_cancel): Remove
macro.
(openat_not_cancel_3): Likewise.
(openat64_not_cancel): Likewise.
(openat64_not_cancel_3): Likewise.
* sysdeps/unix/sysv/linux/openat.c (__openat_nocancel): New function.
* sysdeps/unix/sysv/linux/openat64.c (__openat64_nocancel): Likewise.
* io/ftw.c (open_dir_stream): Replace openat{64}_not_cancel{_3} with
__open{64}_nocancel.
* sysdeps/mach/hurd/opendir.c (__opendirat): Likewise.
* sysdeps/posix/getcwd.c (__getcwd): Likewise.
* sysdeps/posix/opendir.c (__opendirat): Likewise.
This patch consolidates all the non cancellable write calls to use
the __write_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* sysdeps/generic/not-cancel.h (write_not_cancel): Remove macro.
(__write_nocancel): New macro.
* sysdeps/unix/sysv/linux/not-cancel.h (__write_nocancel):
Rewrite as a function prototype.
(write_not_cancel): Remove macro.
* sysdeps/unix/sysv/linux/write.c (__write_nocancel): New function.
* gmon/gmon.c (ERR): Replace write_not_cancel with __write_nocancel.
(write_gmon): Likewise.
* libio/fileops.c (_IO_new_file_write): Likewise.
* login/utmp_file.c (pututline_file): Likewise.
(updwtmp_file): Likewise.
* stdio-common/psiginfo.c (psiginfo): Likewise.
* sysdeps/posix/spawni.c (__spawni_child): Likewise.
* sysdeps/unix/sysv/linux/gethostid.c (sethostid): Likewise.
* sysdeps/unix/sysv/linux/libc_fatal.c (backtrace_and_maps):
Likewise.
* sysdeps/unix/sysv/linux/pthread_setname.c (pthread_setname_np):
Likewise.
This patch consolidates all the non cancellable read calls to use
the __read_nocancel identifier. For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.
Also, since it is used on libcrypto it is also exported in GLIBC_PRIVATE
namespace.
Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.
* sysdeps/generic/not-cancel.h (read_not_cancel): Remove macro.
(__read_nocancel): New macro.
* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
__read_nocancel.
* sysdeps/unix/sysv/linux/not-cancel.h (__read_nocancel): Remove
macro.
(__read_nocancel): New prototype.
* sysdeps/unix/sysv/linux/read.c (__read_nocancel): New function.
* catgets/open_catalog.c (__open_catalog): Replace read_not_cancel
with __read_nocancel.
* intl/loadmsgcat.c (read): Likewise.
* libio/fileops.c (_IO_file_read): Likewise.
* locale/loadlocale.c (_nl_load_locale): Likewise.
* login/utmp_file.c (getutent_r_file): Likewise.
(internal_getut_r): Likewise.
(getutline_r_file): Likewise.
* sysdeps/unix/sysv/linux/fips-private.h (fips_enable_p): Likewise.
* sysdeps/unix/sysv/linux/gethostid.c (gethostid): Likewise.
* sysdeps/unix/sysv/linux/getloadavg.c (getloadavg): Likewise.
* sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid):
Likewise.
* sysdeps/unix/sysv/linux/getsysstats.c (next_line): Likewise.
* sysdeps/unix/sysv/linux/i386/smp.h (is_smp_system): Likewise.
* sysdeps/unix/sysv/linux/ia64/has_cpuclock.c (has_cpuclock):
Likewise.
* sysdeps/unix/sysv/linux/libc_fatal.c (backtrace_and_maps):
Likewise.
* sysdeps/unix/sysv/linux/malloc-sysdep.h (check_may_shrink_heap):
Likewise.
* sysdeps/unix/sysv/linux/pthread_getname.c (pthread_getname_np):
Likewise.
* sysdeps/unix/sysv/linux/sysconf.c (__sysconf): Likewise.
* sysdeps/generic/utmp_file.c: Use not-cancelable syscalls all
over the place. It would be allowed to have these fucntions as
cancellation points but the cleanup would be ugly and a lot of
work.
* sysdeps/generic/not-cancel.h (fcntl_not_cancel): Define.
* sysdeps/unix/sysv/linux/not-cancel.h (fcntl_not_cancel): Define.
* include/fcntl.h (__fcntl_nocancel): Declare.
* sysdeps/unix/sysv/linux/fcntl.c: New file.
* sysdeps/unix/sysv/linux/i386/fcntl.c (__libc_fcntl): Only enable
cancellation if absolutely needed.
(__fcntl_nocancel): Define.
* posix/unistd.h (gethostid): Remove __THROW. Clarify comment.
* sysdeps/unix/sysv/linux/Makefile (CFLAGS-gethostid.c): Add
-fexceptions.
* sysdeps/unix/sysv/linux/gethostid.c (gethostid): Use
extend_alloca.
* resolv/res_init.c (__res_nclose): Use close_not_cancel_no_status
instead of __close.
More cancellation handling fixups.
* sysdeps/unix/sysv/linux/not-cancel.h: Add waitpid_not_cancel.
* sysdeps/generic/not-cancel.h: Likewise.
* catgets/open_catalog.c: Use not-cancelable syscalls.
* time/Makefile (CFLAGS-getdate.c): Add -fexceptions.
* sysdeps/unix/sysv/linux/llseek.c: Must not be cancelable.
* sysdeps/unix/syscalls.list: Don't mark lseek as cancelable.
* dlfcn/dlfcn.h: Mark dlopen with __THROW again.
* io/fcntl.h: Don't mark posix_fallocate with __THROW.
* libio/fileops.c: Use not-cancelable syscalls for fclose.
* libio/iopopen.c: Use no-cancelable syscalls.
* libio/stdio.h: Mark popen and pclose with __THROW again.
* misc/Makefile (CFLAGS-syslog.c): Add -fexceptions.
* misc/syslog.c: Fix locking and cancellation cleanup handling.
* posix/unistd.h: Mark ttyname and ttyname_r again with __THROW.
* stdio-common/Makefile (CFLAGS-tmpfile.c, CFLAGS-tmpfile64.c,
CFLAGS-tempname.c): Add -fexceptions.
* stdlib/Makefile (CFLAGS-mkstemp.c): Add -fexceptions.
* string/string.h: Mark strerror and strerror_r with _THROW again.
* sysdeps/generic/unwind.inc: New file. Copied from gcc.
* sysdeps/generic/unwind-dw2.c: Update from gcc version. Remove
#ifs since we now need all the code compiled.
* sysdeps/posix/spawni.c: Use close_not_cancel instead of close.
* sysdeps/unix/closedir.c: Use not-cancelable syscalls.
* sysdeps/unix/opendir.c: Likewise.
