mariadb/mysys/mf_wfile.c
Davi Arnaut bb036c93b4 Bug#42733: Type-punning warnings when compiling MySQL --
strict aliasing violations.

Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.

As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.

The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.
2010-06-10 17:16:43 -03:00

124 lines
3.1 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 */
/* Functions for finding files with wildcards */
/*
The following file-name-test is supported:
- "name [[,] name...] ; Matches any of used filenames.
Each name can have "*" and/or "?"
wild-cards.
- [wildspec [,]] !wildspec2 ; File that matches wildspec and not
wildspec2.
*/
#include "mysys_priv.h"
#include <m_string.h>
/* Store wildcard-string in a easyer format */
WF_PACK *wf_comp(char * str)
{
uint ant;
int not_pos;
register char * pos;
char * buffer;
WF_PACK *ret;
DBUG_ENTER("wf_comp");
not_pos= -1; /* Skip space and '!' in front */
while (*str == ' ')
str++;
if (*str == '!')
{
not_pos=0;
while (*++str == ' ') {};
}
if (*str == 0) /* Empty == everything */
DBUG_RETURN((WF_PACK *) NULL);
ant=1; /* Count filespecs */
for (pos=str ; *pos ; pos++)
ant+= test(*pos == ' ' || *pos == ',');
if ((ret= (WF_PACK*) my_malloc((uint) ant*(sizeof(char **)+2)+
sizeof(WF_PACK)+ (uint) strlen(str)+1,
MYF(MY_WME)))
== 0)
DBUG_RETURN((WF_PACK *) NULL);
ret->wild= (char **) (ret+1);
buffer= (char *) (ret->wild+ant);
ant=0;
for (pos=str ; *pos ; str= pos)
{
ret->wild[ant++]=buffer;
while (*pos != ' ' && *pos != ',' && *pos != '!' && *pos)
*buffer++ = *pos++;
*buffer++ = '\0';
while (*pos == ' ' || *pos == ',' || *pos == '!' )
if (*pos++ == '!' && not_pos <0)
not_pos=(int) ant;
}
ret->wilds=ant;
if (not_pos <0)
ret->not_pos=ant;
else
ret->not_pos=(uint) not_pos;
DBUG_PRINT("exit",("antal: %d not_pos: %d",ret->wilds,ret->not_pos));
DBUG_RETURN(ret);
} /* wf_comp */
/* Test if a given filename is matched */
int wf_test(register WF_PACK *wf_pack, register const char *name)
{
reg2 uint i;
reg3 uint not_pos;
DBUG_ENTER("wf_test");
if (! wf_pack || wf_pack->wilds == 0)
DBUG_RETURN(0); /* Everything goes */
not_pos=wf_pack->not_pos;
for (i=0 ; i < not_pos; i++)
if (wild_compare(name,wf_pack->wild[i],0) == 0)
goto found;
if (i)
DBUG_RETURN(1); /* No-match */
found:
/* Test that it isn't in not-list */
for (i=not_pos ; i < wf_pack->wilds; i++)
if (wild_compare(name,wf_pack->wild[i],0) == 0)
DBUG_RETURN(1);
DBUG_RETURN(0);
} /* wf_test */
/* We need this because program don't know with malloc we used */
void wf_end(WF_PACK *buffer)
{
DBUG_ENTER("wf_end");
if (buffer)
my_free(buffer, MYF(0));
DBUG_VOID_RETURN;
} /* wf_end */