mariadb/extra/resolveip.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

213 lines
4.9 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 */
/* Resolves IP's to hostname and hostnames to IP's */
#define RESOLVE_VERSION "2.3"
#include <my_global.h>
#include <m_ctype.h>
#include <my_sys.h>
#include <m_string.h>
#ifndef WIN32
# include <sys/types.h>
# include <sys/socket.h>
# ifndef HAVE_BROKEN_NETINET_INCLUDES
# include <netinet/in.h>
# endif
# include <arpa/inet.h>
# include <netdb.h>
#endif
#include <my_net.h>
#include <my_getopt.h>
#if !defined(_AIX) && !defined(h_errno)
extern int h_errno;
#endif
static my_bool silent;
static struct my_option my_long_options[] =
{
{"help", '?', "Displays this help and exits.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"info", 'I', "Synonym for --help.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{"silent", 's', "Be more silent.", &silent, &silent,
0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
{"version", 'V', "Displays version information and exits.",
0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
{ 0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
};
static void print_version(void)
{
printf("%s Ver %s, for %s (%s)\n",my_progname,RESOLVE_VERSION,
SYSTEM_TYPE,MACHINE_TYPE);
}
static void usage(void)
{
print_version();
puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license\n");
puts("Get hostname based on IP-address or IP-address based on hostname.\n");
printf("Usage: %s [OPTIONS] hostname or IP-address\n",my_progname);
my_print_help(my_long_options);
my_print_variables(my_long_options);
}
static my_bool
get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
char *argument __attribute__((unused)))
{
switch (optid) {
case 'V': print_version(); exit(0);
case 'I':
case '?':
usage();
exit(0);
}
return 0;
}
/*static char * load_default_groups[]= { "resolveip","client",0 }; */
static int get_options(int *argc,char ***argv)
{
int ho_error;
if ((ho_error=handle_options(argc, argv, my_long_options, get_one_option)))
exit(ho_error);
if (*argc == 0)
{
usage();
return 1;
}
return 0;
} /* get_options */
int main(int argc, char **argv)
{
struct hostent *hpaddr;
in_addr_t taddr;
char *ip,**q;
int error=0;
MY_INIT(argv[0]);
if (get_options(&argc,&argv))
exit(1);
while (argc--)
{
#ifndef WIN32
struct in_addr addr;
#endif
ip = *argv++;
/* Not compatible with IPv6! Probably should use getnameinfo(). */
#ifdef WIN32
taddr = inet_addr(ip);
if(taddr != INADDR_NONE)
{
#else
if (inet_aton(ip, &addr) != 0)
{
taddr= addr.s_addr;
#endif
if (taddr == htonl(INADDR_BROADCAST))
{
puts("Broadcast");
continue;
}
if (taddr == htonl(INADDR_ANY))
{
if (!taddr)
puts("Null-IP-Addr");
else
puts("Old-Bcast");
continue;
}
hpaddr = gethostbyaddr((char*) &(taddr), sizeof(struct in_addr),AF_INET);
if (hpaddr)
{
if (silent)
puts(hpaddr->h_name);
else
{
printf ("Host name of %s is %s", ip,hpaddr->h_name);
#ifndef __NETWARE__
/* this information is not available on NetWare */
for (q = hpaddr->h_aliases; *q != 0; q++)
(void) printf(", %s", *q);
#endif /* __NETWARE__ */
puts("");
}
}
else
{
error=2;
fprintf(stderr,"%s: Unable to find hostname for '%s'\n",my_progname,
ip);
}
}
else
{
hpaddr = gethostbyname(ip);
if (!hpaddr)
{
const char *err;
fprintf(stderr,"%s: Unable to find hostid for '%s'",my_progname,ip);
switch (h_errno) {
case HOST_NOT_FOUND: err="host not found"; break;
case TRY_AGAIN: err="try again"; break;
case NO_RECOVERY: err="no recovery"; break;
case NO_DATA: err="no_data"; break;
default: err=0;
}
if (err)
fprintf(stderr,": %s\n",err);
else
fprintf(stderr,"\n");
error=2;
}
else if (silent)
{
struct in_addr in;
memcpy((char*) &in.s_addr, (char*) *hpaddr->h_addr_list,
sizeof (in.s_addr));
puts(inet_ntoa(in));
}
else
{
char **p;
for (p = hpaddr->h_addr_list; *p != 0; p++)
{
struct in_addr in;
memcpy(&in.s_addr, *p, sizeof (in.s_addr));
printf ("IP address of %s is %s\n",ip,inet_ntoa(in));
}
}
}
}
exit(error);
}