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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2017-05-02 14:39:58 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2017-05-15 16:33:45 -0300 |
commit | c79a72aa5cb8357c216a71015c7448a9259c8531 (patch) | |
tree | caa8eba1f2827c9aa553c3543e85ada1ea4e37e7 /sysdeps/posix/pwritev.c | |
parent | cdd45522b6e87369afc341402bda7a95bdf83380 (diff) | |
download | glibc-c79a72aa5cb8357c216a71015c7448a9259c8531.tar.gz glibc-c79a72aa5cb8357c216a71015c7448a9259c8531.tar.xz glibc-c79a72aa5cb8357c216a71015c7448a9259c8531.zip |
posix: Fix and simplify default p{read,write}v implementation
Currently all architectures but microblaze use wire-up syscall for p{readv,write}v. Microblaze still uses the syscall emulation using sysdep/posix/p{readv,writev}.c and it was reported in some ocasions [1] [2] that it might have some issues with some linux specific usage (mainly with O_DIRECT and the alignment requirement). Although it is not an issue for virtually all the system, this patch refactors the sysdeps/posix p{read,write}v syscall to avoid such issue (by using posix_memalign on the buffer used on p{read,write} call) and by refactoring it common files to avoid the need check on defines to correct set the alias and internal symbols. Checked on microblaze-linux-gnu check with run-built-tests=no and by using the sysdeps/posix implementation on x86_64-linux-gnu (just for sanity test where it shown no regression). * sysdeps/posix/preadv.c: Use sysdeps/posix/preadv_common.c. * sysdeps/posix/preadv64.c: Likewise. * sysdeps/unix/sysv/linux/preadv.c: Likewise. * sysdeps/unix/sysv/linux/preadv64.c: Likewise. * sysdeps/posix/pwritev.c: Use sysdeps/posix/pwritev_common.c. * sysdeps/posix/pwritev64.c: Likewise. * sysdeps/unix/sysv/linux/pwritev.c: Likewise. * sysdeps/unix/sysv/linux/pwritev64.c: Likewise. * sysdeps/posix/preadv_common.c: New file. * sysdeps/posix/pwritev_common.c: Likewise. [1] http://www.mail-archive.com/qemu-devel@nongnu.org/msg25282.html [2] https://bugzilla.redhat.com/show_bug.cgi?id=563103#c8
Diffstat (limited to 'sysdeps/posix/pwritev.c')
-rw-r--r-- | sysdeps/posix/pwritev.c | 79 |
1 files changed, 7 insertions, 72 deletions
diff --git a/sysdeps/posix/pwritev.c b/sysdeps/posix/pwritev.c index 57e641b8b5..f9de092aa5 100644 --- a/sysdeps/posix/pwritev.c +++ b/sysdeps/posix/pwritev.c @@ -1,4 +1,5 @@ -/* Copyright (C) 2009-2017 Free Software Foundation, Inc. +/* Write data into multiple buffers. Generic version. + Copyright (C) 2009-2017 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -15,81 +16,15 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <errno.h> -#include <stdlib.h> -#include <unistd.h> -#include <string.h> -#include <limits.h> -#include <stdbool.h> -#include <sys/param.h> -#if __WORDSIZE == 64 && !defined PWRITEV -/* Hide the pwritev64 declaration. */ -# define pwritev64 __redirect_pwritev64 -#endif -#include <sys/uio.h> -#include <bits/wordsize.h> +#include <sys/types.h> + +#ifndef __OFF_T_MATCHES_OFF64_T -#ifndef PWRITEV # define PWRITEV pwritev # define PWRITE __pwrite # define OFF_T off_t -#endif - - -static void -ifree (char **ptrp) -{ - free (*ptrp); -} - - -/* Write data pointed by the buffers described by IOVEC, which is a - vector of COUNT 'struct iovec's, to file descriptor FD at the given - position OFFSET without change the file pointer. The data is - written in the order specified. Operates just like 'write' (see - <unistd.h>) except that the data are taken from IOVEC instead of a - contiguous buffer. */ -ssize_t -PWRITEV (int fd, const struct iovec *vector, int count, OFF_T offset) -{ - /* Find the total number of bytes to be read. */ - size_t bytes = 0; - for (int i = 0; i < count; ++i) - { - /* Check for ssize_t overflow. */ - if (SSIZE_MAX - bytes < vector[i].iov_len) - { - __set_errno (EINVAL); - return -1; - } - bytes += vector[i].iov_len; - } - - /* Allocate a temporary buffer to hold the data. We should normally - use alloca since it's faster and does not require synchronization - with other threads. But we cannot if the amount of memory - required is too large. */ - char *buffer; - char *malloced_buffer __attribute__ ((__cleanup__ (ifree))) = NULL; - if (__libc_use_alloca (bytes)) - buffer = (char *) __alloca (bytes); - else - { - malloced_buffer = buffer = (char *) malloc (bytes); - if (buffer == NULL) - return -1; - } +# include <sysdeps/posix/pwritev_common.c> - /* Copy the data from BUFFER into the memory specified by VECTOR. */ - char *ptr = buffer; - for (int i = 0; i < count; ++i) - ptr = __mempcpy ((void *) ptr, (void *) vector[i].iov_base, - vector[i].iov_len); +libc_hidden_def (pwritev) - /* Write the data. */ - return PWRITE (fd, buffer, bytes, offset); -} -#if __WORDSIZE == 64 && defined pwritev64 -# undef pwritev64 -strong_alias (pwritev, pwritev64) #endif |