From 52bd9381692fd23df859fd0e564af247b1571557 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Tue, 25 Apr 2017 16:43:27 -0300 Subject: posix: Implement preadv2 and pwritev2 This patch adds support of preadv2 and pwritev2 which are similar to preadv/pwritev but with an extra flag argument. As for preadv/pwritev both interfaces are added a non-standard GNU API. For default 'posix' implementation trying to emulate the Linux supported flags is troublesome: * We can not temporary change the file state of the O_DSYNC and O_SYNC flags to emulate RWF_{D}SYNC (attempts to change the state of using fcntl are silently ignored). * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal semantic not provided by any other flag (O_NONBLOCK for instance). So default sysdeps/posix implementations fails with EOPNOTSUPP for any non supported flag (which are none currently) calls generic preadv/pwritev. Basically this implementation supports only preadv2 called as preadv (with flags sets to 0). The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it call preadv/writev. Instead of using the previous __ASSUME_* to unconditionally issue the syscall (and avoid building the fallback routine), it call pread/write if the preadv2/pwritev2 syscalls fails. The idea is just avoid adding another __ASSUME_* and checking each architecture on every kernel bump and simplify code conditionals. Checked on x86_64-linux-gnu and on i686-linux-gnu and a check with run-built-tests=no on aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf, ia64-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu, mips{64,64n32}-linux-gnu, nios2-linux-gnu, powerpc{64,64le}-linux-gnu, s390{x}-linux-gnu, sparc{64,v9}-linux-gnu, tile{gx,pro}-linux-gnu, and sh4-linux-gnu (all using gcc 6.3). * NEWS: Add note about pwritev2 and preadv2 inclusion. * misc/Makefile (routines): Add preadv2, preadv64v2, pwritev2, and pwritev64v2. (tests): Add tst-preadvwritev2 and tst-preadvwritev64v2. * misc/Versions (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, and pwritev64v2. * misc/preadv2.c: New file. * misc/preadv64v2.c: Likewise. * misc/pwritev2.c: Likewise. * misc/pwritev64v2.c: Likewise. * misc/tst-preadvwritev2.c: Likewise. * misc/tst-preadvwritev64v2.c: Likewise. * manual/llio.texi: Add preadv2 and pwritev2 documentation. * misc/sys/uio.h [__USE_GNU && !__USE_FILE_OFFSET64] (preadv2): New prototype. [__USE_GNU && !__USE_FILE_OFFSET64] (pwritev2): Likewise. [__USE_GNU && __USE_FILE_OFFSET64] (preadv64v2): Likewise. [__USE_GNU && __USE_FILE_OFFSET64] (pwritev64v2): Likewise. * misc/tst-preadvwritev-common.c (PREADV): Define if not defined. (PWRITEV): Likewise. (do_test_with_offset): Use PREADV and PWRITEV macros and check for ENOSYS. * nptl/tst-cancel4.c (tf_pwritev2): New test. (tf_preadv2): Likewise. (tf_fsync): Add tf_pwritev2 and tf_preadv2. * sysdeps/posix/preadv2.c: Likewise. * sysdeps/posix/preadv64v2.c: Likewise. * sysdeps/posix/pwritev2.c: Likewise. * sysdeps/posix/pwritev64v2.c: Likewise. * sysdeps/unix/sysv/linux/kernel-features.h: Add comment for syscall support in kernel. * sysdeps/unix/sysv/linux/preadv2.c: Likewise. * sysdeps/unix/sysv/linux/preadv64v2.c: Likewise. * sysdeps/unix/sysv/linux/pwritev2.c: Likewise. * sysdeps/unix/sysv/linux/pwritev64v2.c: Likewise. * sysdeps/unix/sysv/linux/preadv.c (preadv): Add libc_hidden_def. * sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise. * sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise. * sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise. * sysdeps/unix/sysv/linux/bits/uio.h: Add supported preadv2/pwritev2 support flags on Linux. * sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, pwritev64v2. * sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/sysv/linux/tile/tilegx/tilegx32/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/sysv/linux/tile/tilegx/tilegx64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.26): Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.26): Likewise. --- NEWS | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'NEWS') diff --git a/NEWS b/NEWS index f92392a..256d8f0 100644 --- a/NEWS +++ b/NEWS @@ -70,6 +70,13 @@ Version 2.26 replacement with a check for integer overflow when calculating total allocation size. +* New preadv2 and pwritev2 has been added. They are Linux extensions to + preadv and pwritev with an additional flag argument where it is possible + to set high priority or use O_DSYNC or O_SYNC for a specific IO operation. + For complete support it requires Linux kernel version 4.6, otherwise a + compat implementation will be used (which refuses all flags and routes it + to preadv or pwritev). + Security related changes: * The DNS stub resolver limits the advertised UDP buffer size to 1200 bytes, -- cgit v1.1