mariadb/vio/vio.c
Davi Arnaut f56dd32bf7 Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.

client/mysqldump.c:
  Pass my_free directly as its signature is compatible with the
  callback type -- which wasn't the case for free_table_ent.
2010-07-08 18:20:08 -03:00

281 lines
8.1 KiB
C

/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Note that we can't have assertion on file descriptors; The reason for
this is that during mysql shutdown, another thread can close a file
we are working on. In this case we should just return read errors from
the file descriptior.
*/
#include "vio_priv.h"
#if defined(__WIN__) || defined(HAVE_SMEM)
/**
Stub poll_read method that defaults to indicate that there
is data to read.
Used for named pipe and shared memory VIO types.
@param vio Unused.
@param timeout Unused.
@retval FALSE There is data to read.
*/
static my_bool no_poll_read(Vio *vio __attribute__((unused)),
uint timeout __attribute__((unused)))
{
return FALSE;
}
#endif
/*
* Helper to fill most of the Vio* with defaults.
*/
static void vio_init(Vio* vio, enum enum_vio_type type,
my_socket sd, HANDLE hPipe, uint flags)
{
DBUG_ENTER("vio_init");
DBUG_PRINT("enter", ("type: %d sd: %d flags: %d", type, sd, flags));
#ifndef HAVE_VIO_READ_BUFF
flags&= ~VIO_BUFFERED_READ;
#endif
bzero((char*) vio, sizeof(*vio));
vio->type = type;
vio->sd = sd;
vio->hPipe = hPipe;
vio->localhost= flags & VIO_LOCALHOST;
if ((flags & VIO_BUFFERED_READ) &&
!(vio->read_buffer= (char*)my_malloc(VIO_READ_BUFFER_SIZE, MYF(MY_WME))))
flags&= ~VIO_BUFFERED_READ;
#ifdef _WIN32
if (type == VIO_TYPE_NAMEDPIPE)
{
vio->viodelete =vio_delete;
vio->vioerrno =vio_errno;
vio->read =vio_read_pipe;
vio->write =vio_write_pipe;
vio->fastsend =vio_fastsend;
vio->viokeepalive =vio_keepalive;
vio->should_retry =vio_should_retry;
vio->was_interrupted=vio_was_interrupted;
vio->vioclose =vio_close_pipe;
vio->peer_addr =vio_peer_addr;
vio->vioblocking =vio_blocking;
vio->is_blocking =vio_is_blocking;
vio->poll_read =no_poll_read;
vio->is_connected =vio_is_connected_pipe;
vio->timeout=vio_win32_timeout;
/* Set default timeout */
vio->read_timeout_ms= INFINITE;
vio->write_timeout_ms= INFINITE;
vio->pipe_overlapped.hEvent= CreateEvent(NULL, TRUE, FALSE, NULL);
DBUG_VOID_RETURN;
}
#endif
#ifdef HAVE_SMEM
if (type == VIO_TYPE_SHARED_MEMORY)
{
vio->viodelete =vio_delete;
vio->vioerrno =vio_errno;
vio->read =vio_read_shared_memory;
vio->write =vio_write_shared_memory;
vio->fastsend =vio_fastsend;
vio->viokeepalive =vio_keepalive;
vio->should_retry =vio_should_retry;
vio->was_interrupted=vio_was_interrupted;
vio->vioclose =vio_close_shared_memory;
vio->peer_addr =vio_peer_addr;
vio->vioblocking =vio_blocking;
vio->is_blocking =vio_is_blocking;
vio->poll_read =no_poll_read;
vio->is_connected =vio_is_connected_shared_memory;
/* Currently, shared memory is on Windows only, hence the below is ok*/
vio->timeout= vio_win32_timeout;
/* Set default timeout */
vio->read_timeout_ms= INFINITE;
vio->write_timeout_ms= INFINITE;
DBUG_VOID_RETURN;
}
#endif
#ifdef HAVE_OPENSSL
if (type == VIO_TYPE_SSL)
{
vio->viodelete =vio_ssl_delete;
vio->vioerrno =vio_errno;
vio->read =vio_ssl_read;
vio->write =vio_ssl_write;
vio->fastsend =vio_fastsend;
vio->viokeepalive =vio_keepalive;
vio->should_retry =vio_should_retry;
vio->was_interrupted=vio_was_interrupted;
vio->vioclose =vio_ssl_close;
vio->peer_addr =vio_peer_addr;
vio->vioblocking =vio_ssl_blocking;
vio->is_blocking =vio_is_blocking;
vio->timeout =vio_timeout;
vio->poll_read =vio_poll_read;
vio->is_connected =vio_is_connected;
DBUG_VOID_RETURN;
}
#endif /* HAVE_OPENSSL */
vio->viodelete =vio_delete;
vio->vioerrno =vio_errno;
vio->read= (flags & VIO_BUFFERED_READ) ? vio_read_buff : vio_read;
vio->write =vio_write;
vio->fastsend =vio_fastsend;
vio->viokeepalive =vio_keepalive;
vio->should_retry =vio_should_retry;
vio->was_interrupted =vio_was_interrupted;
vio->vioclose =vio_close;
vio->peer_addr =vio_peer_addr;
vio->vioblocking =vio_blocking;
vio->is_blocking =vio_is_blocking;
vio->timeout =vio_timeout;
vio->poll_read =vio_poll_read;
vio->is_connected =vio_is_connected;
DBUG_VOID_RETURN;
}
/* Reset initialized VIO to use with another transport type */
void vio_reset(Vio* vio, enum enum_vio_type type,
my_socket sd, HANDLE hPipe, uint flags)
{
my_free(vio->read_buffer);
vio_init(vio, type, sd, hPipe, flags);
}
/* Open the socket or TCP/IP connection and read the fnctl() status */
Vio *vio_new(my_socket sd, enum enum_vio_type type, uint flags)
{
Vio *vio;
DBUG_ENTER("vio_new");
DBUG_PRINT("enter", ("sd: %d", sd));
if ((vio = (Vio*) my_malloc(sizeof(*vio),MYF(MY_WME))))
{
vio_init(vio, type, sd, 0, flags);
sprintf(vio->desc,
(vio->type == VIO_TYPE_SOCKET ? "socket (%d)" : "TCP/IP (%d)"),
vio->sd);
#if !defined(__WIN__)
#if !defined(NO_FCNTL_NONBLOCK)
/*
We call fcntl() to set the flags and then immediately read them back
to make sure that we and the system are in agreement on the state of
things.
An example of why we need to do this is FreeBSD (and apparently some
other BSD-derived systems, like Mac OS X), where the system sometimes
reports that the socket is set for non-blocking when it really will
block.
*/
fcntl(sd, F_SETFL, 0);
vio->fcntl_mode= fcntl(sd, F_GETFL);
#elif defined(HAVE_SYS_IOCTL_H) /* hpux */
/* Non blocking sockets doesn't work good on HPUX 11.0 */
(void) ioctl(sd,FIOSNBIO,0);
vio->fcntl_mode &= ~O_NONBLOCK;
#endif
#else /* !defined(__WIN__) */
{
/* set to blocking mode by default */
ulong arg=0, r;
r = ioctlsocket(sd,FIONBIO,(void*) &arg);
vio->fcntl_mode &= ~O_NONBLOCK;
}
#endif
}
DBUG_RETURN(vio);
}
#ifdef __WIN__
Vio *vio_new_win32pipe(HANDLE hPipe)
{
Vio *vio;
DBUG_ENTER("vio_new_handle");
if ((vio = (Vio*) my_malloc(sizeof(Vio),MYF(MY_WME))))
{
vio_init(vio, VIO_TYPE_NAMEDPIPE, 0, hPipe, VIO_LOCALHOST);
strmov(vio->desc, "named pipe");
}
DBUG_RETURN(vio);
}
#ifdef HAVE_SMEM
Vio *vio_new_win32shared_memory(HANDLE handle_file_map, HANDLE handle_map,
HANDLE event_server_wrote, HANDLE event_server_read,
HANDLE event_client_wrote, HANDLE event_client_read,
HANDLE event_conn_closed)
{
Vio *vio;
DBUG_ENTER("vio_new_win32shared_memory");
if ((vio = (Vio*) my_malloc(sizeof(Vio),MYF(MY_WME))))
{
vio_init(vio, VIO_TYPE_SHARED_MEMORY, 0, 0, VIO_LOCALHOST);
vio->handle_file_map= handle_file_map;
vio->handle_map= handle_map;
vio->event_server_wrote= event_server_wrote;
vio->event_server_read= event_server_read;
vio->event_client_wrote= event_client_wrote;
vio->event_client_read= event_client_read;
vio->event_conn_closed= event_conn_closed;
vio->shared_memory_remain= 0;
vio->shared_memory_pos= handle_map;
strmov(vio->desc, "shared memory");
}
DBUG_RETURN(vio);
}
#endif
#endif
void vio_delete(Vio* vio)
{
if (!vio)
return; /* It must be safe to delete null pointers. */
if (vio->type != VIO_CLOSED)
vio->vioclose(vio);
my_free(vio->read_buffer);
my_free(vio);
}
/*
Cleanup memory allocated by vio or the
components below it when application finish
*/
void vio_end(void)
{
#ifdef HAVE_YASSL
yaSSL_CleanUp();
#endif
}