After some discussion in libc-alpha about this POSIX compliance fix, I see
that GLIBC should indeed revert back to previous definition of msghdr and
cmsghdr and implementation of sendmsg, recvmsg, sendmmsg, recvmmsg due some
reasons:
* The possible issue where the syscalls wrapper add the compatibility
layer is quite limited in scope and range. And kernel current
also add some limits to the values on the internal msghdr and
cmsghdr fields:
- msghdr::msg_iovlen larger than UIO_MAXIOV (1024) returns
EMSGSIZE.
- msghdr::msg_controllen larger than INT_MAX returns ENOBUFS.
* There is a small performance hit for recvmsg/sendmsg/recmmsg which
is neglectable, but it is a big hit for sendmmsg since now instead
of calling the syscall for the packed structure, GLIBC is calling
multiple sendmsg. This defeat the very existence of the syscall.
* It currently breaks libsanitizer build on GCC [1] (I fixed on compiler-rt).
However the fix is incomplete because it does add any runtime check
since libsanitizer currently does not have any facility to intercept
symbols with multiple version [2].
This, along with incorret dlsym/dlvsym return for versioned symbol due
another bug [3], makes hard to interpose versioned symbols.
Also, current approach of fixing GCC PR#71445 leads to half-baked
solutions without versioned symbol interposing.
This patch basically reverts commits 2f0dc39029, 222c2d7f43,
af7f7c7ec8. I decided to not revert abf29edd4a (Adjust
kernel-features.h defaults for recvmsg and sendmsg) mainly because it
does not really address the POSIX compliance original issue and also
adds some cleanups.
Tested on x86, i386, s390, s390x, aarch64, and powerpc64le.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71445
[2] https://github.com/google/sanitizers/issues/628
[3] https://sourceware.org/bugzilla/show_bug.cgi?id=14932
* conform/data/sys/socket.h-data (msghdr.msg_iovlen): Add xfail-.
(msghdr.msg_controllen): Likewise.
(cmsghdr.cmsg_len): Likewise.
* nptl/Makefile (libpthread-routines): Remove ptw-oldrecvmsg and
ptw-oldsendmsg.
(CFLAGS-oldrecvmsg.c): Remove rule.
(CFLAGS-oldsendmsg.c): Likewise.
(CFLAGS-recvmsg.c): Add rule.
(CFLAGS-sendmsg.c): Likewise.
* sysdeps/unix/sysv/linux/Makefile (sysdep_routines): Remove
oldrecvmsg, oldsendmsg, oldrecvmmsg, oldsendmmsg.
(CFLAGS-recvmsg.c): Remove rule.
(CFLAGS-sendmsg.c): Likewise.
(CFLAGS-oldrecvmsg.c): Likewise.
(CFLAGS-oldsendmsg.c): Likewise.
(CFLAGS-recvmmsg.c): Likewise.
* sysdeps/unix/sysv/linux/bits/socket.h (msghdr.msg_iovlen): Revert
to kernel defined interfaces.
(msghdr.msg_controllen): Likewise.
(cmsghdr.cmsg_len): Likewise.
(msghdr.__glibc_reserved1): Remove member.
(msghdr.__glibc_reserved2): Likewise.
(cmsghdr.__glibc_reserved1): Likewise.
* sysdeps/unix/sysv/linux/oldrecvmmsg.c: Remove file.
* sysdeps/unix/sysv/linux/oldrecvmsg.c: Likewise.
* sysdeps/unix/sysv/linux/oldsendmmsg.c: Likewise.
* sysdeps/unix/sysv/linux/oldsendmsg.c: Likewise.
* sysdeps/unix/sysv/linux/recvmmsg.c: Revert back to previous
version.
* sysdeps/unix/sysv/linux/recvmsg.c: Likewise.
* sysdeps/unix/sysv/linux/sendmmsg.c: Likewise.
* sysdeps/unix/sysv/linux/sendmsg.c: Likewise.
* sysdeps/unix/sysv/linux/aarch64/Versions [libc] (GLIBC_2.24):
Remove recvmsg and sendmsg.
* sysdeps/unix/sysv/linux/alpha/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/hppa/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/i386/Versions [libc] (GLIBC_2.24): Likewise.
* sysdeps/unix/sysv/linux/m68k/Versions [libc] (GLIBC_2.24): Likewise.
* sysdeps/unix/sysv/linux/microblaze/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/Versions
[libc] (GLIBC_2.24): Likewise.
* sysdeps/unix/sysv/linux/nios2/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/Versions
[libc] (GLIBC_2.24): Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/sh/Versions [libc] (GLIBC_2.24): Likewise.
* sysdeps/unix/sysv/linux/sparc/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/tile/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/Versions [libc] (GLIBC_2.24):
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/Versions: Remove file
* sysdeps/unix/sysv/linux/x86_64/64/Versions: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/Versions: Likewise.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Remove new 2.24
version for {recv,send,recm,sendm}msg.
* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist: 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/mips/mips64/n64/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/powerpc/powerpc64/libc-le.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
to be of size int and socklen_t respectively, however Linux implements
it as a size_t. So for 64-bits architecture where sizeof of size_t is
larger than socklen_t, both sendmmsg and recvmmsg need to adjust the
mmsghdr::msg_hdr internal fields before issuing the syscall itself.
This patch fixes it by operating on the padding if it the case.
For recvmmsg, the most straightfoward case, only zero padding the fields
is suffice. However, for sendmmsg, where adjusting the buffer is out
of the contract (since it may point to a read-only data), the function
is rewritten to use sendmsg instead (which from previous patch
allocates a temporary msghdr to operate on).
Also for 64-bit ports that requires it, a new recvmmsg and sendmmsg
compat version is created (which uses size_t for both cmsghdr::cmsg_len
and internal
Tested on x86_64, i686, aarch64, armhf, and powerpc64le.
* sysdeps/unix/sysv/linux/Makefile
[$(subdir) = socket] (sysdep_routines): Add oldrecvmmsg and
oldsendmmsg.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Add recvmmsg and
sendmmsg.
* 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/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/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/tile/tilegx/tilegx64/libc.abilist:
Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/oldrecvmmsg.c: New file.
* sysdeps/unix/sysv/linux/oldsendmmsg.c: Likewise.
* sysdeps/unix/sysv/linux/recvmmsg.c (__recvmmsg): Adjust msghdr
iovlen and controllen fields to adjust to POSIX specification.
* sysdeps/unix/sysv/linux/sendmmsg.c (__sendmmsg): Likewise.
This patch removes the socket.S implementation for all ports and replace
it by a C implementation using socketcall. For ports that implement
the syscall directly, there is no change.
The patch idea is to simplify the socket function implementation that
uses the socketcall to be based on C implemetation instead of a pseudo
assembly implementation with arch specific parts. The patch then remove
the assembly implementatation for the ports which uses socketcall
(i386, microblaze, mips, powerpc, sparc, m68k, s390 and sh).
I have cross-build GLIBC for afore-mentioned ports and tested on both
i386 and ppc32 without regressions.
Similar to the issues for accept4, __ASSUME_RECVMMSG is also confused
about whether it relates to function availability or socketcall
operation availability; this is now bug 16610.
Nothing actually tests __ASSUME_RECVMMSG for function availability,
but implicit in the definition in kernel-features.h is the idea that
it makes sense when the syscall is available and socketcall is not
being used. As with accept4, there are architectures where the
syscall was added later than the socketcall operation, meaning that
assuming glibc is built with recent enough kernel headers, it does not
attempt to use socketcall for these operations and __ASSUME_RECVMMSG
gets defined for kernels >= 2.6.33 even when the syscall was only
added later.
This patch splits the macro into separate macros like those used for
accept4; having similar macro structure in both cases (and for
sendmmsg once I've dealt with that) seems likely to be less confusing
than having a different structure on the basis of nothing actually
needing to assume the recvmmsg function works. Appropriate
definitions are added for all architectures.
Architecture-specific note: Tile's kernel-features.h says "TILE glibc
support starts with 2.6.36", which is accurate in that 2.6.36 was the
first kernel version with Tile support, and on that basis I've made
that header define __ASSUME_RECVMMSG_SYSCALL unconditionally.
However, Tile's configure.ac has arch_minimum_kernel=2.6.32. Since
arch_minimum_kernel is meant to reflect only kernel.org kernel
versions, I think that should change to 2.6.36. (If using glibc with
kernel versions from before a port went in kernel.org, it's your
responsibility to change arch_minimum_kernel in a local patch, and at
the same time to adjust any __ASSUME_* definitions that may not be
correct for your older kernel; for developing the official glibc it
should only ever be necessary to consider what official kernel.org
releases support.)
Tested x86_64, including that disassembly of the installed shared
libraries is unchanged by this patch.
[BZ #16610]
* sysdeps/unix/sysv/linux/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621 && __ASSUME_SOCKETCALL]
(__ASSUME_RECVMMSG_SOCKETCALL): Define.
[(__LINUX_KERNEL_VERSION >= 0x020621 && (__i386__ || __x86_64__ ||
__sparc__)) || (__LINUX_KERNEL_VERSION >= 0x020625 && (__powerpc__
|| __sh__))] (__ASSUME_RECVMMSG_SYSCALL): Likewise.
[__i386__ || __sparc__]
(__ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL): Likewise.
[__ASSUME_RECVMMSG_SOCKETCALL || __ASSUME_RECVMMSG_SYSCALL]
(__ASSUME_RECVMMSG): Define instead of using previous
[__LINUX_KERNEL_VERSION >= 0x020621] condition.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Define.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/internal_recvmmsg.S [__ASSUME_SOCKETCALL
&& !__ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_RECVMMSG_SYSCALL] (__NR_recvmmsg): Undefine.
[__ASSUME_RECVMMSG]: Change condition to
[__ASSUME_RECVMMSG_SOCKETCALL].
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Define.
(__ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL): Likewise.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/recvmmsg.c [__ASSUME_SOCKETCALL &&
!__ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_RECVMMSG_SYSCALL] (__NR_recvmmsg): Undefine.
[!__ASSUME_RECVMMSG]: Change condition to
[!__ASSUME_RECVMMSG_SOCKETCALL].
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Define.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020622] (__ASSUME_RECVMMSG_SYSCALL):
Define.
