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mariadb/sql/sql_udf.cc
Sergei Golubchik bfe703a458 don't let current_thd to point to a destroyed THD 
* reset current_thd in THD::~THD, otherwise my_malloc_size_cb_func()
  might access THD after it was destroyed.
* remove now redundant set_current_thd(0) calls that follow delete thd.
2015-02-03 18:19:56 +01:00

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/* Copyright (c) 2000, 2012, Oracle and/or its affiliates.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/* This implements 'user defined functions' */
/*
Known bugs:
Memory for functions is never freed!
Shared libraries are not closed before mysqld exits;
- This is because we can't be sure if some threads are using
a function.
The bugs only affect applications that create and free a lot of
dynamic functions, so this shouldn't be a real problem.
*/
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include <my_global.h>
#include "sql_priv.h"
#include "unireg.h"
#include "sql_base.h" // close_mysql_tables
#include "sql_parse.h" // check_identifier_name
#include "sql_table.h" // write_bin_log
#include "records.h" // init_read_record, end_read_record
#include <my_pthread.h>
#include "lock.h" // MYSQL_LOCK_IGNORE_TIMEOUT
#ifdef HAVE_DLOPEN
extern "C"
{
#include <stdarg.h>
#include <hash.h>
}
static bool initialized = 0;
static MEM_ROOT mem;
static HASH udf_hash;
static mysql_rwlock_t THR_LOCK_udf;
static udf_func *add_udf(LEX_STRING *name, Item_result ret,
char *dl, Item_udftype typ);
static void del_udf(udf_func *udf);
static void *find_udf_dl(const char *dl);
static char *init_syms(udf_func *tmp, char *nm)
{
char *end;
if (!((tmp->func= (Udf_func_any) dlsym(tmp->dlhandle, tmp->name.str))))
return tmp->name.str;
end=strmov(nm,tmp->name.str);
if (tmp->type == UDFTYPE_AGGREGATE)
{
(void)strmov(end, "_clear");
if (!((tmp->func_clear= (Udf_func_clear) dlsym(tmp->dlhandle, nm))))
return nm;
(void)strmov(end, "_add");
if (!((tmp->func_add= (Udf_func_add) dlsym(tmp->dlhandle, nm))))
return nm;
}
(void) strmov(end,"_deinit");
tmp->func_deinit= (Udf_func_deinit) dlsym(tmp->dlhandle, nm);
(void) strmov(end,"_init");
tmp->func_init= (Udf_func_init) dlsym(tmp->dlhandle, nm);
/*
to prefent loading "udf" from, e.g. libc.so
let's ensure that at least one auxiliary symbol is defined
*/
if (!tmp->func_init && !tmp->func_deinit && tmp->type != UDFTYPE_AGGREGATE)
{
if (!opt_allow_suspicious_udfs)
return nm;
if (current_thd->variables.log_warnings)
sql_print_warning(ER(ER_CANT_FIND_DL_ENTRY), nm);
}
return 0;
}
extern "C" uchar* get_hash_key(const uchar *buff, size_t *length,
my_bool not_used __attribute__((unused)))
{
udf_func *udf=(udf_func*) buff;
*length=(uint) udf->name.length;
return (uchar*) udf->name.str;
}
#ifdef HAVE_PSI_INTERFACE
static PSI_rwlock_key key_rwlock_THR_LOCK_udf;
static PSI_rwlock_info all_udf_rwlocks[]=
{
{ &key_rwlock_THR_LOCK_udf, "THR_LOCK_udf", PSI_FLAG_GLOBAL}
};
static void init_udf_psi_keys(void)
{
const char* category= "sql";
int count;
if (PSI_server == NULL)
return;
count= array_elements(all_udf_rwlocks);
PSI_server->register_rwlock(category, all_udf_rwlocks, count);
}
#endif
/*
Read all predeclared functions from mysql.func and accept all that
can be used.
*/
void udf_init()
{
udf_func *tmp;
TABLE_LIST tables;
READ_RECORD read_record_info;
TABLE *table;
int error;
DBUG_ENTER("ufd_init");
char db[]= "mysql"; /* A subject to casednstr, can't be constant */
if (initialized)
DBUG_VOID_RETURN;
#ifdef HAVE_PSI_INTERFACE
init_udf_psi_keys();
#endif
mysql_rwlock_init(key_rwlock_THR_LOCK_udf, &THR_LOCK_udf);
init_sql_alloc(&mem, UDF_ALLOC_BLOCK_SIZE, 0, MYF(0));
THD *new_thd = new THD;
if (!new_thd ||
my_hash_init(&udf_hash,system_charset_info,32,0,0,get_hash_key, NULL, 0))
{
sql_print_error("Can't allocate memory for udf structures");
my_hash_free(&udf_hash);
free_root(&mem,MYF(0));
delete new_thd;
DBUG_VOID_RETURN;
}
initialized = 1;
new_thd->thread_stack= (char*) &new_thd;
new_thd->store_globals();
new_thd->set_db(db, sizeof(db)-1);
tables.init_one_table(db, sizeof(db)-1, "func", 4, "func", TL_READ);
if (open_and_lock_tables(new_thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
{
DBUG_PRINT("error",("Can't open udf table"));
sql_print_error("Can't open the mysql.func table. Please "
"run mysql_upgrade to create it.");
goto end;
}
table= tables.table;
if (init_read_record(&read_record_info, new_thd, table, NULL,1,0,FALSE))
{
sql_print_error("Could not initialize init_read_record; udf's not "
"loaded");
goto end;
}
table->use_all_columns();
while (!(error= read_record_info.read_record(&read_record_info)))
{
DBUG_PRINT("info",("init udf record"));
LEX_STRING name;
name.str=get_field(&mem, table->field[0]);
name.length = (uint) strlen(name.str);
char *dl_name= get_field(&mem, table->field[2]);
bool new_dl=0;
Item_udftype udftype=UDFTYPE_FUNCTION;
if (table->s->fields >= 4) // New func table
udftype=(Item_udftype) table->field[3]->val_int();
/*
Ensure that the .dll doesn't have a path
This is done to ensure that only approved dll from the system
directories are used (to make this even remotely secure).
On windows we must check both FN_LIBCHAR and '/'.
*/
if (check_valid_path(dl_name, strlen(dl_name)) ||
check_string_char_length(&name, "", NAME_CHAR_LEN,
system_charset_info, 1))
{
sql_print_error("Invalid row in mysql.func table for function '%.64s'",
name.str);
continue;
}
if (!(tmp= add_udf(&name,(Item_result) table->field[1]->val_int(),
dl_name, udftype)))
{
sql_print_error("Can't alloc memory for udf function: '%.64s'", name.str);
continue;
}
void *dl = find_udf_dl(tmp->dl);
if (dl == NULL)
{
char dlpath[FN_REFLEN];
strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", tmp->dl,
NullS);
(void) unpack_filename(dlpath, dlpath);
if (!(dl= dlopen(dlpath, RTLD_NOW)))
{
/* Print warning to log */
sql_print_error(ER(ER_CANT_OPEN_LIBRARY), tmp->dl, errno, dlerror());
/* Keep the udf in the hash so that we can remove it later */
continue;
}
new_dl=1;
}
tmp->dlhandle = dl;
{
char buf[SAFE_NAME_LEN+16], *missing;
if ((missing= init_syms(tmp, buf)))
{
sql_print_error(ER(ER_CANT_FIND_DL_ENTRY), missing);
del_udf(tmp);
if (new_dl)
dlclose(dl);
}
}
}
if (error > 0)
sql_print_error("Got unknown error: %d", my_errno);
end_read_record(&read_record_info);
table->m_needs_reopen= TRUE; // Force close to free memory
end:
close_mysql_tables(new_thd);
delete new_thd;
DBUG_VOID_RETURN;
}
void udf_free()
{
/* close all shared libraries */
DBUG_ENTER("udf_free");
for (uint idx=0 ; idx < udf_hash.records ; idx++)
{
udf_func *udf=(udf_func*) my_hash_element(&udf_hash,idx);
if (udf->dlhandle) // Not closed before
{
/* Mark all versions using the same handler as closed */
for (uint j=idx+1 ; j < udf_hash.records ; j++)
{
udf_func *tmp=(udf_func*) my_hash_element(&udf_hash,j);
if (udf->dlhandle == tmp->dlhandle)
tmp->dlhandle=0; // Already closed
}
dlclose(udf->dlhandle);
}
}
my_hash_free(&udf_hash);
free_root(&mem,MYF(0));
if (initialized)
{
initialized= 0;
mysql_rwlock_destroy(&THR_LOCK_udf);
}
DBUG_VOID_RETURN;
}
static void del_udf(udf_func *udf)
{
DBUG_ENTER("del_udf");
if (!--udf->usage_count)
{
my_hash_delete(&udf_hash,(uchar*) udf);
using_udf_functions=udf_hash.records != 0;
}
else
{
/*
The functions is in use ; Rename the functions instead of removing it.
The functions will be automaticly removed when the least threads
doesn't use it anymore
*/
char *name= udf->name.str;
uint name_length=udf->name.length;
udf->name.str=(char*) "*";
udf->name.length=1;
my_hash_update(&udf_hash,(uchar*) udf,(uchar*) name,name_length);
}
DBUG_VOID_RETURN;
}
void free_udf(udf_func *udf)
{
DBUG_ENTER("free_udf");
if (!initialized)
DBUG_VOID_RETURN;
mysql_rwlock_wrlock(&THR_LOCK_udf);
if (!--udf->usage_count)
{
/*
We come here when someone has deleted the udf function
while another thread still was using the udf
*/
my_hash_delete(&udf_hash,(uchar*) udf);
using_udf_functions=udf_hash.records != 0;
if (!find_udf_dl(udf->dl))
dlclose(udf->dlhandle);
}
mysql_rwlock_unlock(&THR_LOCK_udf);
DBUG_VOID_RETURN;
}
/* This is only called if using_udf_functions != 0 */
udf_func *find_udf(const char *name,uint length,bool mark_used)
{
udf_func *udf=0;
DBUG_ENTER("find_udf");
if (!initialized)
DBUG_RETURN(NULL);
DEBUG_SYNC(current_thd, "find_udf_before_lock");
/* TODO: This should be changed to reader locks someday! */
if (mark_used)
mysql_rwlock_wrlock(&THR_LOCK_udf); /* Called during fix_fields */
else
mysql_rwlock_rdlock(&THR_LOCK_udf); /* Called during parsing */
if ((udf=(udf_func*) my_hash_search(&udf_hash,(uchar*) name,
length ? length : (uint) strlen(name))))
{
if (!udf->dlhandle)
udf=0; // Could not be opened
else if (mark_used)
udf->usage_count++;
}
mysql_rwlock_unlock(&THR_LOCK_udf);
DBUG_RETURN(udf);
}
static void *find_udf_dl(const char *dl)
{
DBUG_ENTER("find_udf_dl");
/*
Because only the function name is hashed, we have to search trough
all rows to find the dl.
*/
for (uint idx=0 ; idx < udf_hash.records ; idx++)
{
udf_func *udf=(udf_func*) my_hash_element(&udf_hash,idx);
if (!strcmp(dl, udf->dl) && udf->dlhandle != NULL)
DBUG_RETURN(udf->dlhandle);
}
DBUG_RETURN(0);
}
/* Assume that name && dl is already allocated */
static udf_func *add_udf(LEX_STRING *name, Item_result ret, char *dl,
Item_udftype type)
{
if (!name || !dl || !(uint) type || (uint) type > (uint) UDFTYPE_AGGREGATE)
return 0;
udf_func *tmp= (udf_func*) alloc_root(&mem, sizeof(udf_func));
if (!tmp)
return 0;
bzero((char*) tmp,sizeof(*tmp));
tmp->name = *name; //dup !!
tmp->dl = dl;
tmp->returns = ret;
tmp->type = type;
tmp->usage_count=1;
if (my_hash_insert(&udf_hash,(uchar*) tmp))
return 0;
using_udf_functions=1;
return tmp;
}
/*
Drop user defined function.
@param thd Thread handler.
@param udf Existing udf_func pointer which is to be deleted.
@param table mysql.func table reference (opened and locked)
Assumption
- udf is not null.
- table is already opened and locked
*/
static int mysql_drop_function_internal(THD *thd, udf_func *udf, TABLE *table)
{
DBUG_ENTER("mysql_drop_function_internal");
char *exact_name_str= udf->name.str;
uint exact_name_len= udf->name.length;
del_udf(udf);
/*
Close the handle if this was function that was found during boot or
CREATE FUNCTION and it's not in use by any other udf function
*/
if (udf->dlhandle && !find_udf_dl(udf->dl))
dlclose(udf->dlhandle);
if (!table)
DBUG_RETURN(1);
table->use_all_columns();
table->field[0]->store(exact_name_str, exact_name_len, &my_charset_bin);
if (!table->file->ha_index_read_idx_map(table->record[0], 0,
(uchar*) table->field[0]->ptr,
HA_WHOLE_KEY,
HA_READ_KEY_EXACT))
{
int error;
if ((error= table->file->ha_delete_row(table->record[0])))
table->file->print_error(error, MYF(0));
}
DBUG_RETURN(0);
}
/**
Create a user defined function.
@note Like implementations of other DDL/DML in MySQL, this function
relies on the caller to close the thread tables. This is done in the
end of dispatch_command().
*/
int mysql_create_function(THD *thd,udf_func *udf)
{
int error;
void *dl=0;
bool new_dl=0;
TABLE *table;
TABLE_LIST tables;
udf_func *u_d;
DBUG_ENTER("mysql_create_function");
if (!initialized)
{
if (opt_noacl)
my_error(ER_CANT_INITIALIZE_UDF, MYF(0),
udf->name.str,
"UDFs are unavailable with the --skip-grant-tables option");
else
my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));
DBUG_RETURN(1);
}
/*
Ensure that the .dll doesn't have a path
This is done to ensure that only approved dll from the system
directories are used (to make this even remotely secure).
*/
if (check_valid_path(udf->dl, strlen(udf->dl)))
{
my_message(ER_UDF_NO_PATHS, ER(ER_UDF_NO_PATHS), MYF(0));
DBUG_RETURN(1);
}
if (check_string_char_length(&udf->name, "", NAME_CHAR_LEN,
system_charset_info, 1))
{
my_error(ER_TOO_LONG_IDENT, MYF(0), udf->name.str);
DBUG_RETURN(1);
}
tables.init_one_table(STRING_WITH_LEN("mysql"), STRING_WITH_LEN("func"),
"func", TL_WRITE);
table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
mysql_rwlock_wrlock(&THR_LOCK_udf);
DEBUG_SYNC(current_thd, "mysql_create_function_after_lock");
if ((u_d= (udf_func*) my_hash_search(&udf_hash, (uchar*) udf->name.str,
udf->name.length)))
{
if (thd->lex->create_info.or_replace())
{
if ((error= mysql_drop_function_internal(thd, u_d, table)))
goto err;
}
else if (thd->lex->create_info.if_not_exists())
{
push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, ER_UDF_EXISTS,
ER(ER_UDF_EXISTS), udf->name.str);
goto done;
}
else
{
my_error(ER_UDF_EXISTS, MYF(0), udf->name.str);
goto err;
}
}
if (!(dl = find_udf_dl(udf->dl)))
{
char dlpath[FN_REFLEN];
strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", udf->dl, NullS);
(void) unpack_filename(dlpath, dlpath);
if (!(dl = dlopen(dlpath, RTLD_NOW)))
{
DBUG_PRINT("error",("dlopen of %s failed, error: %d (%s)",
udf->dl, errno, dlerror()));
my_error(ER_CANT_OPEN_LIBRARY, MYF(0),
udf->dl, errno, dlerror());
goto err;
}
new_dl=1;
}
udf->dlhandle=dl;
{
char buf[SAFE_NAME_LEN+16], *missing;
if ((missing= init_syms(udf, buf)))
{
my_error(ER_CANT_FIND_DL_ENTRY, MYF(0), missing);
goto err;
}
}
udf->name.str= strdup_root(&mem,udf->name.str);
udf->dl= strdup_root(&mem,udf->dl);
if (!(u_d=add_udf(&udf->name,udf->returns,udf->dl,udf->type)))
goto err;
u_d->dlhandle= dl;
u_d->func= udf->func;
u_d->func_init= udf->func_init;
u_d->func_deinit= udf->func_deinit;
u_d->func_clear= udf->func_clear;
u_d->func_add= udf->func_add;
/* create entry in mysql.func table */
/* Allow creation of functions even if we can't open func table */
if (!table)
goto err;
table->use_all_columns();
restore_record(table, s->default_values); // Default values for fields
table->field[0]->store(u_d->name.str, u_d->name.length, system_charset_info);
table->field[1]->store((longlong) u_d->returns, TRUE);
table->field[2]->store(u_d->dl,(uint) strlen(u_d->dl), system_charset_info);
if (table->s->fields >= 4) // If not old func format
table->field[3]->store((longlong) u_d->type, TRUE);
error = table->file->ha_write_row(table->record[0]);
if (error)
{
my_error(ER_ERROR_ON_WRITE, MYF(0), "mysql.func", error);
del_udf(u_d);
goto err;
}
done:
mysql_rwlock_unlock(&THR_LOCK_udf);
/* Binlog the create function. */
if (write_bin_log(thd, TRUE, thd->query(), thd->query_length()))
DBUG_RETURN(1);
DBUG_RETURN(0);
err:
if (new_dl)
dlclose(dl);
mysql_rwlock_unlock(&THR_LOCK_udf);
DBUG_RETURN(1);
}
int mysql_drop_function(THD *thd,const LEX_STRING *udf_name)
{
TABLE *table;
TABLE_LIST tables;
udf_func *udf;
DBUG_ENTER("mysql_drop_function");
if (!initialized)
{
if (opt_noacl)
my_error(ER_FUNCTION_NOT_DEFINED, MYF(0), udf_name->str);
else
my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));
DBUG_RETURN(1);
}
tables.init_one_table(STRING_WITH_LEN("mysql"), STRING_WITH_LEN("func"),
"func", TL_WRITE);
table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);
mysql_rwlock_wrlock(&THR_LOCK_udf);
DEBUG_SYNC(current_thd, "mysql_drop_function_after_lock");
if (!(udf= (udf_func*) my_hash_search(&udf_hash, (uchar*) udf_name->str,
(uint) udf_name->length)) )
{
if (thd->lex->check_exists)
{
push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
ER_FUNCTION_NOT_DEFINED, ER(ER_FUNCTION_NOT_DEFINED),
udf_name->str);
goto done;
}
my_error(ER_FUNCTION_NOT_DEFINED, MYF(0), udf_name->str);
goto err;
}
if (mysql_drop_function_internal(thd, udf, table))
goto err;
done:
mysql_rwlock_unlock(&THR_LOCK_udf);
/*
Binlog the drop function. Keep the table open and locked
while binlogging, to avoid binlog inconsistency.
*/
if (write_bin_log(thd, TRUE, thd->query(), thd->query_length()))
DBUG_RETURN(1);
DBUG_RETURN(0);
err:
mysql_rwlock_unlock(&THR_LOCK_udf);
DBUG_RETURN(1);
}
#endif /* HAVE_DLOPEN */
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