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MDEV-10907 MTR and server writes can interleave in the error log

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Ensure atomic appends to the error log by using CreateFile with
FILE_APPEND_DATA flag to open error log file (both MTR and server)
This commit is contained in:
Vladislav Vaintroub 2016-09-27 12:34:15 +00:00
parent d61e5260fb
commit b38d3c3d8a
3 changed files with 56 additions and 8 deletions
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49
mysql-test/lib/My/Platform.pm
View File

@ -24,7 +24,7 @@ use File::Path;
use base qw(Exporter);
our @EXPORT= qw(IS_CYGWIN IS_WINDOWS IS_WIN32PERL
native_path posix_path mixed_path
check_socket_path_length process_alive);
check_socket_path_length process_alive open_for_append);
BEGIN {
if ($^O eq "cygwin") {
@ -161,4 +161,51 @@ sub process_alive {
}
use Symbol qw( gensym );
use if $^O eq 'MSWin32', 'Win32API::File', qw( CloseHandle CreateFile GetOsFHandle OsFHandleOpen OPEN_ALWAYS FILE_APPEND_DATA
FILE_SHARE_READ FILE_SHARE_WRITE FILE_SHARE_DELETE );
use if $^O eq 'MSWin32', 'Win32::API';
use constant WIN32API_FILE_NULL => [];
# Open a file for append
# On Windows we use CreateFile with FILE_APPEND_DATA
# to insure that writes are atomic, not interleaved
# with writes by another processes.
sub open_for_append
{
my ($file) = @_;
my $fh = gensym();
if (IS_WIN32PERL)
{
my $handle;
if (!($handle = CreateFile(
$file,
FILE_APPEND_DATA(),
FILE_SHARE_READ()|FILE_SHARE_WRITE()|FILE_SHARE_DELETE(),
WIN32API_FILE_NULL,
OPEN_ALWAYS(),# Create if doesn't exist.
0,
WIN32API_FILE_NULL,
)))
{
return undef;
}
if (!OsFHandleOpen($fh, $handle, 'wat'))
{
CloseHandle($handle);
return undef;
}
return $fh;
}
open($fh,">>",$file) or return undef;
return $fh;
}
1;

9
mysql-test/lib/mtr_io.pl
View File

@ -21,6 +21,7 @@
use strict;
use Carp;
use My::Platform;
sub mtr_fromfile ($);
sub mtr_tofile ($@);
@ -45,10 +46,10 @@ sub mtr_fromfile ($) {
sub mtr_tofile ($@) {
my $file= shift;
open(FILE,">>",$file) or mtr_error("can't open file \"$file\": $!");
print FILE join("", @_);
close FILE;
my $fh= open_for_append $file;
mtr_error("can't open file \"$file\": $!") unless defined($fh);
print $fh join("", @_);
close $fh;
}

6
mysys/my_fopen.c
View File

@ -102,6 +102,7 @@ static FILE *my_win_freopen(const char *path, const char *mode, FILE *stream)
HANDLE osfh;
DBUG_ASSERT(path && stream);
DBUG_ASSERT(strchr(mode, 'a')); /* We use FILE_APPEND_DATA below */
/* Services don't have stdout/stderr on Windows, so _fileno returns -1. */
if (fd < 0)
@ -112,15 +113,14 @@ static FILE *my_win_freopen(const char *path, const char *mode, FILE *stream)
fd= _fileno(stream);
}
if ((osfh= CreateFile(path, GENERIC_READ | GENERIC_WRITE,
if ((osfh= CreateFile(path, GENERIC_READ | FILE_APPEND_DATA,
FILE_SHARE_READ | FILE_SHARE_WRITE |
FILE_SHARE_DELETE, NULL,
OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL,
NULL)) == INVALID_HANDLE_VALUE)
return NULL;
if ((handle_fd= _open_osfhandle((intptr_t)osfh,
_O_APPEND | _O_TEXT)) == -1)
if ((handle_fd= _open_osfhandle((intptr_t)osfh, _O_TEXT)) == -1)
{
CloseHandle(osfh);
return NULL;