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-rw-r--r--sql/hostname.cc235
1 files changed, 235 insertions, 0 deletions
diff --git a/sql/hostname.cc b/sql/hostname.cc
new file mode 100644
index 00000000000..0e8d6e36f0f
--- /dev/null
+++ b/sql/hostname.cc
@@ -0,0 +1,235 @@
+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
+ (at your option) any later version.
+
+ 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 */
+
+
+/*
+ Get hostname for an IP. Hostnames are checked with reverse name lookup and
+ checked that they doesn't resemble an ip.
+*/
+
+#include "mysql_priv.h"
+#include "hash_filo.h"
+#include <m_ctype.h>
+#ifdef __cplusplus
+extern "C" { // Because of SCO 3.2V4.2
+#endif
+#ifndef __WIN__
+#include <sys/resource.h>
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h>
+#endif
+#include <netdb.h>
+#include <sys/utsname.h>
+#endif // __WIN__
+#ifdef __cplusplus
+}
+#endif
+
+
+class host_entry :public hash_filo_element
+{
+public:
+ char ip[sizeof(((struct in_addr *) 0)->s_addr)];
+ uint errors;
+ char *hostname;
+};
+
+static hash_filo *hostname_cache;
+
+void hostname_cache_refresh()
+{
+ hostname_cache->clear();
+}
+
+bool hostname_cache_init()
+{
+ if (!(hostname_cache=new hash_filo(HOST_CACHE_SIZE,offsetof(host_entry,ip),
+ sizeof(struct in_addr),NULL,
+ (void (*)(void*)) free)))
+ return 1;
+ hostname_cache->clear();
+ return 0;
+}
+
+void hostname_cache_free()
+{
+ delete hostname_cache;
+}
+
+static void add_hostname(struct in_addr *in,const char *name)
+{
+ if (!(specialflag & SPECIAL_NO_HOST_CACHE))
+ {
+ VOID(pthread_mutex_lock(&hostname_cache->lock));
+ host_entry *entry;
+ if (!(entry=(host_entry*) hostname_cache->search((gptr) &in->s_addr,0)))
+ {
+ uint length=name ? strlen(name) : 0;
+
+ if ((entry=(host_entry*) malloc(sizeof(host_entry)+length+1)))
+ {
+ char *new_name= (char *) (entry+1);
+ memcpy_fixed(&entry->ip, &in->s_addr, sizeof(in->s_addr));
+ memcpy(new_name, name, length); // Should work even if name == NULL
+ new_name[length]=0; // End of string
+ entry->hostname=new_name;
+ entry->errors=0;
+ (void) hostname_cache->add(entry);
+ }
+ }
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ }
+}
+
+
+static inline void add_wrong_ip(struct in_addr *in)
+{
+ add_hostname(in,NullS);
+}
+
+void inc_host_errors(struct in_addr *in)
+{
+ VOID(pthread_mutex_lock(&hostname_cache->lock));
+ host_entry *entry;
+ if ((entry=(host_entry*) hostname_cache->search((gptr) &in->s_addr,0)))
+ entry->errors++;
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+}
+
+void reset_host_errors(struct in_addr *in)
+{
+ VOID(pthread_mutex_lock(&hostname_cache->lock));
+ host_entry *entry;
+ if ((entry=(host_entry*) hostname_cache->search((gptr) &in->s_addr,0)))
+ entry->errors=0;
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+}
+
+
+my_string ip_to_hostname(struct in_addr *in, uint *errors)
+{
+ host_entry *entry;
+ DBUG_ENTER("ip_to_hostname");
+
+ /* Check first if we have name in cache */
+ *errors=0;
+ if (!(specialflag & SPECIAL_NO_HOST_CACHE))
+ {
+ VOID(pthread_mutex_lock(&hostname_cache->lock));
+ if ((entry=(host_entry*) hostname_cache->search((gptr) &in->s_addr,0)))
+ {
+ char *name;
+ if (!entry->hostname)
+ name=0; // Don't allow connection
+ else
+ name=my_strdup(entry->hostname,MYF(0));
+ *errors= entry->errors;
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ DBUG_RETURN(name);
+ }
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ }
+
+ struct hostent *hp, *check;
+ char *name;
+ LINT_INIT(check);
+#if defined(HAVE_GETHOSTBYADDR_R) && defined(HAVE_SOLARIS_STYLE_GETHOST)
+ char buff[GETHOSTBYADDR_BUFF_SIZE],buff2[GETHOSTBYNAME_BUFF_SIZE];
+ int tmp_errno;
+ struct hostent tmp_hostent, tmp_hostent2;
+#ifdef HAVE_purify
+ bzero(buff,sizeof(buff)); // Bug in purify
+#endif
+ if (!(hp=gethostbyaddr_r((char*) in,sizeof(*in),
+ AF_INET,
+ &tmp_hostent,buff,sizeof(buff),&tmp_errno)))
+ {
+ DBUG_PRINT("error",("gethostbyaddr_r returned %d",tmp_errno));
+ return 0;
+ }
+ if (!(check=my_gethostbyname_r(hp->h_name,&tmp_hostent2,buff2,sizeof(buff2),
+ &tmp_errno)))
+ {
+ DBUG_PRINT("error",("gethostbyname_r returned %d",tmp_errno));
+ add_wrong_ip(in);
+ DBUG_RETURN(0);
+ }
+ if (!hp->h_name[0])
+ {
+ DBUG_PRINT("error",("Got an empty hostname"));
+ add_wrong_ip(in);
+ DBUG_RETURN(0); // Don't allow empty hostnames
+ }
+ if (!(name=my_strdup(hp->h_name,MYF(0))))
+ DBUG_RETURN(0); // out of memory
+
+#else
+ VOID(pthread_mutex_lock(&hostname_cache->lock));
+ if (!(hp=gethostbyaddr((char*) in,sizeof(*in), AF_INET)))
+ {
+ DBUG_PRINT("error",("gethostbyaddr returned %d",errno));
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ add_wrong_ip(in);
+ DBUG_RETURN(0);
+ }
+ if (!hp->h_name[0])
+ {
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ DBUG_PRINT("error",("Got an empty hostname"));
+ add_wrong_ip(in);
+ DBUG_RETURN(0); // Don't allow empty hostnames
+ }
+ if (!(name=my_strdup(hp->h_name,MYF(0))))
+ DBUG_RETURN(0); // out of memory
+ check=gethostbyname(name);
+ VOID(pthread_mutex_unlock(&hostname_cache->lock));
+ if (!check)
+ {
+ DBUG_PRINT("error",("gethostbyname returned %d",errno));
+ my_free(name,MYF(0));
+ DBUG_RETURN(0);
+ }
+#endif
+
+ /* Don't accept hostnames that starts with digits because they may be
+ false ip:s */
+ if (isdigit(name[0]))
+ {
+ char *pos;
+ for (pos= name+1 ; isdigit(*pos); pos++) ;
+ if (*pos == '.')
+ {
+ DBUG_PRINT("error",("mysqld doesn't accept hostnames that starts with a number followed by a '.'"));
+ my_free(name,MYF(0));
+ add_wrong_ip(in);
+ DBUG_RETURN(0);
+ }
+ }
+
+ /* Check that 'gethostbyname' returned the used ip */
+ for (uint i=0; check->h_addr_list[i]; i++)
+ {
+ if (*(uint32*)(check->h_addr_list)[i] == in->s_addr)
+ {
+ add_hostname(in,name);
+ DBUG_RETURN(name);
+ }
+ }
+ DBUG_PRINT("error",("Couldn't verify hostname with gethostbyname"));
+ my_free(name,MYF(0));
+ add_wrong_ip(in);
+ DBUG_RETURN(0);
+}
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