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linux: fix support for preadv/pwritev-less kernels

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The fix from commit 269ff0be is wrong in that it sniffs system headers
to determine if preadv() and pwrite() are supported.

It breaks the fs_write_multiple_bufs test on one of my ARM systems;
its glibc has preadv() and pwritev() wrappers but its kernel has no
support for the corresponding system calls.

Simply try the system call and fall back to a normal read or write
loop if not supported.  Move the no_preadv and no_pwritev variables
around to squelch two -Wpedantic warnings about mixing declarations
with code.

PR-URL: https://github.com/libuv/libuv/pull/90
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
This commit is contained in:
Ben Noordhuis 2014-12-28 01:15:37 +01:00
parent 2daee9fbeb
commit af96f458e2
1 changed files with 10 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/unix/fs.c
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@ -35,8 +35,10 @@
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
@ -48,30 +50,12 @@
defined(__OpenBSD__) || \
defined(__NetBSD__)
# define HAVE_PREADV 1
#elif defined(__linux__)
# include <linux/version.h>
# if defined(__GLIBC_PREREQ)
# if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,30) && \
__GLIBC_PREREQ(2,10)
# define HAVE_PREADV 1
# else
# define HAVE_PREADV 0
# endif
# else
# define HAVE_PREADV 0
# endif
#else
# define HAVE_PREADV 0
#endif
#if defined(__linux__) || defined(__sun)
# include <sys/sendfile.h>
#elif defined(__APPLE__) || defined(__FreeBSD__)
# include <sys/socket.h>
#endif
#if HAVE_PREADV || defined(__APPLE__)
# include <sys/uio.h>
#endif
#define INIT(type) \
@ -219,6 +203,9 @@ static ssize_t uv__fs_mkdtemp(uv_fs_t* req) {
static ssize_t uv__fs_read(uv_fs_t* req) {
#if defined(__linux__)
static int no_preadv;
#endif
ssize_t result;
#if defined(_AIX)
@ -245,16 +232,12 @@ static ssize_t uv__fs_read(uv_fs_t* req) {
result = preadv(req->file, (struct iovec*) req->bufs, req->nbufs, req->off);
#else
# if defined(__linux__)
static int no_preadv;
if (no_preadv)
if (no_preadv) retry:
# endif
{
off_t nread;
size_t index;
# if defined(__linux__)
retry:
# endif
nread = 0;
index = 0;
result = 1;
@ -578,6 +561,9 @@ static ssize_t uv__fs_utime(uv_fs_t* req) {
static ssize_t uv__fs_write(uv_fs_t* req) {
#if defined(__linux__)
static int no_pwritev;
#endif
ssize_t r;
/* Serialize writes on OS X, concurrent write() and pwrite() calls result in
@ -603,16 +589,12 @@ static ssize_t uv__fs_write(uv_fs_t* req) {
r = pwritev(req->file, (struct iovec*) req->bufs, req->nbufs, req->off);
#else
# if defined(__linux__)
static int no_pwritev;
if (no_pwritev)
if (no_pwritev) retry:
# endif
{
off_t written;
size_t index;
# if defined(__linux__)
retry:
# endif
written = 0;
index = 0;
r = 0;