This will allow us to change many aspects of the malloc implementation
while preserving compatibility with existing Emacs binaries.
As a result, existing Emacs binaries will have a larger RSS, and Emacs
needs a few more milliseconds to start. This overhead is specific
to Emacs (and will go away once Emacs switches to its internal malloc).
The new checks to make free and realloc compatible with the dumped heap
are confined to the mmap paths, which are already quite slow due to the
munmap overhead.
This commit weakens some security checks, but only for heap pointers
in the dumped main arena. By default, this area is empty, so those
checks are as effective as before.
This patch corrects spurious conformtest expectations of getdate and
getdate_err for XPG3. (This is not based on a full review of the
expectations, so there may be other issues where the header and tests
agree but are both incorrect.)
Tested for x86_64 and x86.
* conform/data/time.h-data (getdate_err): Do not expect for
[XPG3].
(getdate): Likewise.
* conform/Makefile (test-xfail-XPG3/time.h/conform): Remove
variable.
The conformtest tests of unistd.h fail for XPG3 because of various
expectations that are incorrect for XPG3. This patch corrects those
bogus expectations, and one bogus expectation for XPG4. (This is not
based on a full review of the standards so there may well still be
other bugs in the expectations for this header.)
Tested for x86_64 and x86.
* conform/data/unistd.h-data (F_LOCK): Do not expect for [XPG3].
(F_ULOCK): Likewise.
(F_TEST): Likewise.
(F_TLOCK): Likewise.
(useconds_t): Likewise.
(intptr_t): Do not expect for [XPG3] or [XPG4].
(brk): Do not expect for [XPG3]
(fchown): Likewise.
(fchdir): Likewise.
(ftruncate): Likewise.
(getdtablesize): Likewise.
(gethostid): Likewise.
(getpagesize): Likewise.
(getpgid): Likewise.
(getsid): Likewise.
(getwd): Likewise.
(lchown): Likewise.
(lockf): Likewise.
(readlink): Likewise.
(sbrk): Likewise.
(setpgrp): Likewise.
(setregid): Likewise.
(setreuid): Likewise.
(symlink): Likewise.
(sync): Likewise.
(truncate): Likewise.
(ualarm): Likewise.
(usleep): Likewise.
(vfork): Likewise.
* conform/Makefile (test-xfail-XPG3/unistd.h/conform): Remove
variable.
unistd.h declares gethostname for __USE_UNIX98 || __USE_XOPEN2K. But
it's also in XPG4 (XNS volume - C438 - not the main definitions of
system interfaces and headers in C435). This patch corrects the
condition.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20054]
* posix/unistd.h (gethostname): Declare if [__USE_XOPEN_EXTENDED],
not [__USE_UNIX98].
* conform/data/unistd.h-data (gethostname): Do not expect for
[XPG3].
The conform/ tests for fcntl.h are failing for XPG3 and XPG4 because
of missing S_IFSOCK.
This is a case of a bogus test. The relevant wording requiring such
constants is, in current POSIX (and this requirement dates back as far
as XPG4), "The <fcntl.h> header shall define the symbolic constants
for file modes for use as values of mode_t as described in
<sys/stat.h>.". Note that this is *file modes* not *file types*.
That makes sense, since the point is presumably for use with functions
such as open that are declared in fcntl.h, where file modes are
relevant but file types aren't. So this patch removes all those
spurious S_IF* expectations for fcntl.h (the macros are generally
still *allowed* through the permission to make everything from
sys/stat.h visible).
Tested for x86_64 and x86.
* conform/data/fcntl.h-data [!POSIX] (S_IFMT): Do not expect.
[!POSIX] (S_IFBLK): Likewise.
[!POSIX] (S_IFCHR): Likewise.
[!POSIX] (S_IFIFO): Likewise.
[!POSIX] (S_IFREG): Likewise.
[!POSIX] (S_IFDIR): Likewise.
[!POSIX] (S_IFLNK): Likewise.
[!POSIX] (S_IFSOCK): Likewise.
* conform/Makefile (test-xfail-XPG3/fcntl.h/conform): Remove
variable.
(test-xfail-XPG4/fcntl.h/conform): Likewise.
small sets of up to 16 bytes, medium of 16..96 bytes which are fully unrolled.
Large memsets of more than 96 bytes align the destination and use an unrolled
loop processing 64 bytes per iteration. Memsets of zero of more than 256 use
the dc zva instruction, and there are faster versions for the common ZVA sizes
64 or 128. STP of Q registers is used to reduce codesize without loss of
performance.
The speedup on test-memset is 1% on Cortex-A57 and 8% on Cortex-A53.
* sysdeps/aarch64/memset.S (__memset):
Rewrite of optimized memset.
This provides a band-aid and addresses the scenario where fork is
called from a signal handler while the process is in the malloc
subsystem (or has acquired the libio list lock). It does not
address the general issue of async-signal-safety of fork;
multi-threaded processes are not covered, and some glibc
subsystems have fork handlers which are not async-signal-safe.
termios.h should declare tcgetsid for XPG4, but only does so for
__USE_UNIX98 || __USE_XOPEN2K8 at present. This patch fixes the
declaration conditions. A spurious conformtest expectation of this
declaration for XPG3 is removed, and two XFAILs that are fixed by
these changes are also removed.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20055]
* termios/termios.h (pid_t): Define for [__USE_XOPEN_EXTENDED]
instead of [__USE_UNIX98].
(tcgetsid): Declare for [__USE_XOPEN_EXTENDED] instead of
[__USE_UNIX98].
* conform/data/termios.h-data (tcgetsid): Do not expect for
[XPG3].
* conform/Makefile (test-xfail-XPG3/termios.h/conform): Remove
variable.
(test-xfail-XPG4/termios.h/conform): Likewise.
if glibc is build with -march=z900 | -march=z990,
the startup file gcrt1.o (used if you link with gcc -pg)
contains R_390_GOT12 | R_390_GOT20 relocations.
Thus, an entry in the GOT can be addressed relative to the GOT pointer
with a 12 | 20 bit displacement value.
The startup files should not contain R_390_GOT12,
R_390_GOT20 relocations, but R_390_GOTENT ones.
This patch removes the overrides of pic-ccflag and
the default pic-ccflag = -fPIC in Makeconfig
is used instead to get the R_390_GOTENT relocations in gcrt1.o.
ChangeLog:
* sysdeps/s390/s390-32/Makefile (pic-ccflag): Remove.
* sysdeps/s390/s390-64/Makefile: Likewise.
Merge x86 ifunc-defines.sym with x86 cpu-features-offsets.sym. Remove
x86 ifunc-defines.sym and rtld-global-offsets.sym. No code changes on
i686 and x86-64.
* sysdeps/i386/i686/multiarch/Makefile (gen-as-const-headers):
Remove ifunc-defines.sym.
* sysdeps/x86_64/multiarch/Makefile (gen-as-const-headers):
Likewise.
* sysdeps/i386/i686/multiarch/ifunc-defines.sym: Removed.
* sysdeps/x86/rtld-global-offsets.sym: Likewise.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Likewise.
* sysdeps/x86/Makefile (gen-as-const-headers): Remove
rtld-global-offsets.sym.
* sysdeps/x86_64/multiarch/ifunc-defines.sym: Merged with ...
* sysdeps/x86/cpu-features-offsets.sym: This.
* sysdeps/x86/cpu-features.h: Include <cpu-features-offsets.h>
instead of <ifunc-defines.h> and <rtld-global-offsets.h>.
sys/stat.h declares fchmod if __USE_POSIX (i.e. POSIX.1:1990). But it
was actually added in 1993 and also in XPG4. This patch changes the
conditions to the correct __USE_POSIX199309 || __USE_XOPEN_EXTENDED.
Tested for x86_64 and x86 (testsuite, and that installed shared
libraries are unchanged by the patch).
[BZ #20073]
* io/sys/stat.h (fchmod): Declare for
[__USE_POSIX199309 || __USE_XOPEN_EXTENDED], not [__USE_POSIX].
* conform/Makefile (test-xfail-XPG3/sys/stat.h/conform): Remove
variable.
This patch fixes various conformtest sys/stat.h expectations that were
incorrect for XPG3 (not based on a full review, so not necessarily an
exhaustive set of such corrections). Most of these corrections fix
spurious failures shown in testing (but that for fchmod introduces a
correct failure, as that function is wrongly declared for XPG3, so
this doesn't eliminate any XFAILs).
Tested for x86_64 and x86.
* conform/data/sys/stat.h-data [XPG3] (S_IFLNK): Do not expect.
[XPG3] (S_IFSOCK): Likewise.
[XPG3] (S_ISVTX): Likewise.
[XPG3] (S_ISLNK): Likewise.
[XPG3] (S_ISSOCK): Likewise.
[XPG3] (fchmod): Likewise.
[XPG3] (lstat): Likewise.
[XPG3] (mknod): Likewise.
The conformtest expectations expect the struct stat fields st_blksize
and st_blocks to be of types blksize_t and blkcnt_t. But XPG4 does
not have those types, using long instead, and XPG3 does not have these
fields at all. This patch adjusts the expectations for those
standards, XFAILing them for XPG4 to allow for systems where the
typedefs don't correspond to long.
Tested for x86_64 and x86.
* conform/data/sys/stat.h-data (st_blksize): Do not expect for
[XPG3]. Expect type long and XFAIL for [XPG4].
(st_blocks): Likewise.
For UNIX98 (only), unistd.h should declare pthread_atfork, but that
declaration is missing. This patch adds it.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20044]
* posix/unistd.h [__USE_UNIX98 && !__USE_XOPEN2K]
(pthread_atfork): New prototype.
* conform/Makefile (test-xfail-UNIX98/unistd.h/conform): Remove
variable.
For UNIX98 and older X/Open standards, unistd.h should have a
declaration of the legacy cuserid function, but such a declaration is
missing. This patch adds that missing declaration.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20043]
* posix/unistd.h [__USE_XOPEN && !__USE_XOPEN2K] (cuserid): New
prototype.
The conformtest tests for sys/types.h for XPG3 and XPG4 fail because
of missing blksize_t. This is a bug in the expectations; that type is
not part of those standards. This patch stops the tests from
expecting it, and some other types that also are not part of XPG3 and
XPG4.
Tested for x86_64 and x86.
* conform/data/sys/types.h-data (blkcnt_t): Do not expect for
[XPG3 || XPG4].
(blksize_t): Likewise.
(clockid_t): Likewise.
* conform/Makefile (test-xfail-XPG3/sys/types.h/conform): Remove
variable.
(test-xfail-XPG4/sys/types.h/conform): Likewise.
This patch adds support for symbol __kernel_getcpu in vDSO,
which is available with kernel 4.5.
Now sched_getcpu is using this symbol if available in mapped vDSO
by defining macro HAVE_GETCPU_VSYSCALL. If not available at runtime,
the former syscall is used.
Move sysdeps/x86_64/cacheinfo.c to sysdeps/x86. No code changes on x86
and x86_64.
* sysdeps/i386/cacheinfo.c: Include <sysdeps/x86/cacheinfo.c>
instead of <sysdeps/x86_64/cacheinfo.c>.
* sysdeps/x86_64/cacheinfo.c: Moved to ...
* sysdeps/x86/cacheinfo.c: Here.
* sysdeps/pthread/aio_misc.c (__aio_enqueue_request): Do not write
`running` field of `newp` when a thread was started to process it,
since that thread will not take `__aio_requests_mutex`, and the field
already has the proper value actually.
The AF_LOCAL and AF_INET/AF_INET6 non-numerci service conversion
did not return EAI_OVERFLOW if the supplied buffer was too small,
silently returning truncated data. In the AF_INET/AF_INET6
numeric cases, the snprintf return value checking was incorrect.
In the numeric AF_INET/AF_INET6 case, if inet_ntop fails
as the result of a short host buffer, we used to call strnlen
on the uninitialized host buffer.
The file sysdeps/powerpc/sysdeps.h defines aliases for condition register
operands. E.g.: 'cr7' means condition register 7. On the one hand, this
increases readability, as it makes it easier for readers to know whether the
operand is a condition register, a general purpose register or an immediate.
On the other hand, this permits that condition registers be written as if they
were general purpose, and vice-versa, thus reducing the readability of the
code.
This commit removes some of these unintentional misuses.
The changes have no effect on the final code. Checked with objdump.
Instead, we store the data we need from the return value of
readdir in an object of the new type struct readdir_result.
This type is independent of the layout of struct dirent.
For UNIX98 and older standards, sys/time.h should not define struct
timespec, but does so via the inclusion of sys/select.h (which is a
new header in the 2001 edition of POSIX, and defines struct timespec
because of the declaration of pselect, a new function in the 2001
edition of POSIX). In turn, this affects some other headers that
themselves include sys/time.h.
This patch fixes this by conditioning the __need_timespec definition
in sys/select.h on __USE_XOPEN2K, the same condition used there for
the declaration of pselect (this has no effect on direct uses of
sys/select.h with feature test macros for any standard that includes
that header, since such standards result in __USE_XOPEN2K being
defined).
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20041]
* misc/sys/select.h (__need_timespec): Only define if
[__USE_XOPEN2K].
* conform/Makefile (test-xfail-XPG4/sys/time.h/conform): Remove
variable.
(test-xfail-XPG4/utmpx.h/conform): Likewise.
(test-xfail-UNIX98/sys/time.h/conform): Likewise.
(test-xfail-UNIX98/utmpx.h/conform): Likewise.
fcntl.h defines struct timespec if __USE_XOPEN || __USE_XOPEN2K8. But
(a) the subsequent bits/stat.h include only needs it if __USE_XOPEN2K8
and (b) older standards did not allow struct timespec here. (It's
allowed for newer standards by virtue of the permission to include
symbols from sys/stat.h. But sys/stat.h is only required to provide
struct timespec from the 2008 edition of POSIX onwards, and permitted
by the 2004 TC to the 2001 edition in anticipation of the addition of
nanosecond timestamp support to struct stat in the 2008 edition.)
This patch limits the timespec definition to the __USE_XOPEN2K8 case,
that being the only case where it is actually needed for the
<bits/stat.h> include.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #20023]
* io/fcntl.h [__USE_XOPEN && !__USE_XOPEN2K8]: Do not include
<time.h>.
* conform/Makefile (test-xfail-UNIX98/fcntl.h/conform): Remove
variable.
(test-xfail-XOPEN2K/fcntl.h/conform): Likewise.
This patch fixes the clone CLONE_VM change from 0cb313f (BZ#19957)
where the commit changed the register that contains the save flags
argument to compare with (from r28 to r29). This patch changes
back to correct register.
Tested on powerpc32 (thanks to Tulio Magno Quites Machado Filho).
* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S (__clone): Fix
flags CLONE_VM compare.
The Hesiod implementation imported into glibc was enhanced
to support caller-supplied resolver states. But its only
consumer is nss_hesiod, and it supplies the thread-local
resolver state. Therefore, this commit changes the Hesiod
implementation to use the thread-local resolver state (_res)
directly. This fixes bug 19573 because the Hesiod
implementation no longer has to initialize and free any
resolver state.
To avoid any risk of interposition of ABI-incompatible Hesiod
function implementations, this commit marks the Hesiod functions
as hidden. (They were already hidden using a linker version
script.)
https://sourceware.org/glibc/wiki/Proposals/GroupMerging
== Justification ==
It is common today for users to rely on centrally-managed user stores for
handling their user accounts. However, much software existing today does
not have an innate understanding of such accounts. Instead, they commonly
rely on membership in known groups for managing access-control (for
example the "wheel" group on Fedora and RHEL systems or the "adm" group
on Debian-derived systems). In the present incarnation of nsswitch, the
only way to have such groups managed by a remote user store such as
FreeIPA or Active Directory would be to manually remove the groups from
/etc/group on the clients so that nsswitch would then move past nss_files
and into the SSSD, nss-ldap or other remote user database.
== Solution ==
With this patch, a new action is introduced for nsswitch:
NSS_ACTION_MERGE. To take advantage of it, one will add [SUCCESS=merge]
between two database entries in the nsswitch.conf file. When a group is
located in the first of the two group entries, processing will continue
on to the next one. If the group is also found in the next entry (and the
group name and GID are an exact match), the member list of the second
entry will be added to the group object to be returned.
== Implementation ==
After each DL_LOOKUP_FN() returns, the next action is checked. If the
function returned NSS_STATUS_SUCCESS and the next action is
NSS_ACTION_MERGE, a copy of the result buffer is saved for the next pass
through the loop. If on this next pass through the loop the database
returns another instance of a group matching both the group name and GID,
the member list is added to the previous list and it is returned as a
single object. If the following database does not contain the same group,
then the original is copied back into the destination buffer.
This patch implements merge functionality only for the group database.
For other databases, there is a default implementation that will return
the EINVAL errno if a merge is requested. The merge functionality can be
implemented for other databases at a later time if such is needed. Each
database must provide a unique implementation of the deep-copy and merge
functions.
If [SUCCESS=merge] is present in nsswitch.conf for a glibc version that
does not support it, glibc will process results up until that operation,
at which time it will return results if it has found them or else will
simply return an error. In practical terms, this ends up behaving like
the remainder of the nsswitch.conf line does not exist.
== Iterators ==
This feature does not modify the iterator functionality from its current
behavior. If getgrnam() or getgrgid() is called, glibc will iterate
through all entries in the `group` line in nsswitch.conf and display the
list of members without attempting to merge them. This is consistent with
the behavior of nss_files where if two separate lines are specified for
the same group in /etc/groups, getgrnam()/getgrgid() will display both.
Clients are already expected to handle this gracefully.
== No Premature Optimizations ==
The following is a list of places that might be eligible for
optimization, but were not overengineered for this initial contribution:
* Any situation where a merge may occur will result in one malloc() of
the same size as the input buffer.
* Any situation where a merge does occur will result in a second
malloc() to hold the list of pointers to member name strings.
* The list of members is simply concatenated together and is not tested
for uniqueness (which is identical to the behavior for nss_files,
which will simply return identical values if they both exist on the
line in the file. This could potentially be optimized to reduce space
usage in the buffer, but it is both complex and computationally
expensive to do so.
== Testing ==
I performed testing by running the getent utility against my newly-built
glibc and configuring /etc/nsswitch.conf with the following entry:
group: group: files [SUCCESS=merge] sss
In /etc/group I included the line:
wheel❌10:sgallagh
I then configured my local SSSD using the id_provider=local to respond
with:
wheel:*:10:localuser,localuser2
I then ran `getent group wheel` against the newly-built glibc in
multiple situations and received the expected output as described
above:
* When SSSD was running.
* When SSSD was configured in nsswitch.conf but the daemon was not
running.
* When SSSD was configured in nsswitch.conf but nss_sss.so.2 was not
installed on the system.
* When the order of 'sss' and 'files' was reversed.
* All of the above with the [SUCCESS=merge] removed (to ensure no
regressions).
* All of the above with `getent group 10`.
* All of the above with `getent group` with and without
`enumerate=true` set in SSSD.
* All of the above with and without nscd enabled on the system.
The fmemopen implementation does not account the file position correctly in
append mode. The following example shows the failure:
===
int main ()
{
char buf[10] = "test";
FILE *fp = fmemopen (buf, 10, "a+");
fseek (fp, 0, SEEK_SET);
int gr;
if ((gr = getc (fp)) != 't' ||
(gr = getc (fp)) != 'e' ||
(gr = getc (fp)) != 's' ||
(gr = getc (fp)) != 't' ||
(gr = getc (fp)) != EOF)
{
printf ("%s: getc failed returned %i\n", __FUNCTION__, gr);
return 1;
}
return 0;
}
===
This is due both how read and write operation update the buffer position,
taking in consideration buffer lenght instead of maximum position defined
by the open mode. This patch fixes it and also fixes fseek not returning
EINVAL for invalid whence modes.
Tested on x86_64 and i686.
[BZ #20012]
* libio/fmemopen.c (fmemopen_read): Use buffer maximum position, not
length to calculate the buffer to read.
(fmemopen_write): Set the buffer position based on bytes written.
(fmemopen_seek): Return EINVAL for invalid whence modes.
As discussed in libc-alpha [1] current clone with CLONE_VM (without
CLONE_THREAD set) will reset the pthread pid/tid fields to -1. The
issue is since memory is shared between the parent and child it will
clobber parent's cached pid/tid leading to internal inconsistencies
if the value is not restored.
And even it is restored it may lead to racy conditions when between
set/restore a thread might invoke pthread function that validate the
pthread with INVALID_TD_P/INVALID_NOT_TERMINATED_TD_P and thus get
wrong results.
As stated in BZ19957, previously reports of this behaviour was close
with EWONTFIX due the fact usage of clone outside glibc is tricky
since glibc requires consistent internal pthread, while using clone
directly may not provide it. However since now posix_spawn uses
clone (CLONE_VM) to fixes various issues related to previous vfork
usage this issue requires fixing.
The vfork implementation also does something similar, but instead
it negates and restores only the *pid* field and functions that
might access its value know to handle such case (getpid, raise
and pthread ones that uses INVALID_TD_P/INVALID_NOT_TERMINATED_TD_P
macros that check only *tid* field). Also vfork does not call
__clone directly, instead calling either __NR_vfork or __NR_clone
directly.
So this patch removes this clone behavior by avoiding setting
the pthread pid/tid field for CLONE_VM. There is no need to
check for CLONE_THREAD, since the minimum supported kernel in all
architecture implies that CLONE_VM must be used with CLONE_THREAD,
otherwise clone returns EINVAL.
Instead of current approach of:
int clone(int (*fn)(void *), void *child_stack, int flags, ...)
[...]
if (flags & CLONE_THREAD)
goto do_syscall;
pid_t new_value;
if (flags & CLONE_VM)
new_value = -1;
else
new_value = getpid ();
THREAD_SETMEM (THREAD_SELF, pid, new_value);
THREAD_SETMEM (THREAD_SELF, tid, new_value);
do_syscall:
[...]
The new approach uses:
int clone(int (*fn)(void *), void *child_stack, int flags, ...)
[...]
if (flags & CLONE_VM)
goto do_syscall;
pid_t new_value = getpid ();
THREAD_SETMEM (THREAD_SELF, pid, new_value);
THREAD_SETMEM (THREAD_SELF, tid, new_value);
do_syscall:
[...]
It also removes the linux tst-getpid2.c test which expects the previous
behavior and instead add another clone test.
Tested on x86_64, i686, x32, powerpc64le, aarch64, armhf, s390, and
s390x. I also did limited check on mips32 and sparc64 (using the new
added test).
I also got reviews from both m68k, hppa, and tile. So I presume for
these architecture the patch works.
The fixes for alpha, microblaze, sh, ia64, and nio2 have not been
tested.
[1] https://sourceware.org/ml/libc-alpha/2016-04/msg00307.html
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == nptl] (test): Remove
tst-getpid2.
(test): Add tst-clone2.
* sysdeps/unix/sysv/linux/tst-clone2.c: New file.
* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone): Do not change
pid/tid fields for CLONE_VM.
* sysdeps/unix/sysv/linux/arm/clone.S: Likewise.
* sysdeps/unix/sysv/linux/i386/clone.S: Likewise.
* sysdeps/unix/sysv/linux/mips/clone.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/x86_64/clone.S: Likewise.
* sysdeps/unix/sysv/linux/tst-getpid2.c: Remove file.
Call __memset_power8 to pad, with zeros, the remaining bytes in the
dest string on __strncpy_power8 and __stpncpy_power8. This improves
performance when n is larger than the input string, giving ~30% gain for
larger strings without impacting much shorter strings.
When converting a struct hostent response to struct gaih_addrtuple, the
gethosts macro (which is called from gaih_inet) used alloca, without
malloc fallback for large responses. This commit changes this code to
use calloc unconditionally.
This commit also consolidated a second hostent-to-gaih_addrtuple
conversion loop (in gaih_inet) to use the new conversion function.
