~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2003 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 */

/* create and drop of databases */

#include <drizzled/global.h>

#include CSTDINT_H

#include CINTTYPES_H

#include <string>

#include <fstream>

#include <drizzled/serialize/serialize.h>

using namespace std;

#include <drizzled/server_includes.h>

#include <mysys/mysys_err.h>

#include <mysys/my_dir.h>

#include "log.h"

#include <drizzled/error.h>

#include <drizzled/gettext.h>

#include <mysys/hash.h>

#include <drizzled/session.h>

#include <drizzled/db.h>

#include <drizzled/sql_base.h>

#include <drizzled/lock.h>

#include <drizzled/errmsg_print.h>

#define MAX_DROP_TABLE_Q_LEN      1024

const char *del_exts[]= {".frm", ".BAK", ".TMD",".opt", NULL};

static TYPELIB deletable_extentions=

{array_elements(del_exts)-1,"del_exts", del_exts, NULL};

static long mysql_rm_known_files(Session *session, MY_DIR *dirp,

                                 const char *db, const char *path,

                                 uint32_t level,

                                 TableList **dropped_tables);

static bool rm_dir_w_symlink(const char *org_path, bool send_error);

static void mysql_change_db_impl(Session *session,

                                 LEX_STRING *new_db_name,

                                 const CHARSET_INFO * const new_db_charset);

/* Database lock hash */

HASH lock_db_cache;

pthread_mutex_t LOCK_lock_db;

int creating_database= 0;  // how many database locks are made

/* Structure for database lock */

typedef struct my_dblock_st

{

  char *name;        /* Database name        */

  uint32_t name_length;  /* Database length name */

} my_dblock_t;

/*

  lock_db key.

*/

extern "C" unsigned char* lock_db_get_key(my_dblock_t *, size_t *, bool not_used);

unsigned char* lock_db_get_key(my_dblock_t *ptr, size_t *length,

                       bool not_used __attribute__((unused)))

{

  *length= ptr->name_length;

  return (unsigned char*) ptr->name;

}

/*

  Free lock_db hash element.

*/

extern "C" void lock_db_free_element(void *ptr);

void lock_db_free_element(void *ptr)

{

  free(ptr);

}

/*

  Delete a database lock entry from hash.

*/

void lock_db_delete(const char *name, uint32_t length)

{

  my_dblock_t *opt;

  safe_mutex_assert_owner(&LOCK_lock_db);

  if ((opt= (my_dblock_t *)hash_search(&lock_db_cache,

                                       (const unsigned char*) name, length)))

    hash_delete(&lock_db_cache, (unsigned char*) opt);

}

/* Database options hash */

static HASH dboptions;

static bool dboptions_init= 0;

static pthread_rwlock_t LOCK_dboptions;

/* Structure for database options */

typedef struct my_dbopt_st

{

  char *name;			/* Database name                  */

  uint32_t name_length;		/* Database length name           */

  const CHARSET_INFO *charset;	/* Database default character set */

} my_dbopt_t;

/*

  Function we use in the creation of our hash to get key.

*/

extern "C" unsigned char* dboptions_get_key(my_dbopt_t *opt, size_t *length,

                                    bool not_used);

unsigned char* dboptions_get_key(my_dbopt_t *opt, size_t *length,

                         bool not_used __attribute__((unused)))

{

  *length= opt->name_length;

  return (unsigned char*) opt->name;

}

/*

  Helper function to write a query to binlog used by mysql_rm_db()

*/

static inline void write_to_binlog(Session *session, char *query, uint32_t q_len,

                                   char *db, uint32_t db_len)

{

  Query_log_event qinfo(session, query, q_len, 0, 0);

  qinfo.error_code= 0;

  qinfo.db= db;

  qinfo.db_len= db_len;

  drizzle_bin_log.write(&qinfo);

}

/*

  Function to free dboptions hash element

*/

extern "C" void free_dbopt(void *dbopt);

void free_dbopt(void *dbopt)

{

  free((unsigned char*) dbopt);

}

/*

  Initialize database option hash and locked database hash.

  SYNOPSIS

    my_database_names()

  NOTES

    Must be called before any other database function is called.

  RETURN

    0	ok

    1	Fatal error

*/

bool my_database_names_init(void)

{

  bool error= false;

  (void) pthread_rwlock_init(&LOCK_dboptions, NULL);

  if (!dboptions_init)

  {

    dboptions_init= 1;

    error= hash_init(&dboptions, lower_case_table_names ?

                     &my_charset_bin : system_charset_info,

                     32, 0, 0, (hash_get_key) dboptions_get_key,

                     free_dbopt,0) ||

           hash_init(&lock_db_cache, lower_case_table_names ?

                     &my_charset_bin : system_charset_info,

                     32, 0, 0, (hash_get_key) lock_db_get_key,

                     lock_db_free_element,0);

  }

  return error;

}

/*

  Free database option hash and locked databases hash.

*/

void my_database_names_free(void)

{

  if (dboptions_init)

  {

    dboptions_init= 0;

    hash_free(&dboptions);

    (void) pthread_rwlock_destroy(&LOCK_dboptions);

    hash_free(&lock_db_cache);

  }

}

/*

  Cleanup cached options

*/

void my_dbopt_cleanup(void)

{

  pthread_rwlock_wrlock(&LOCK_dboptions);

  hash_free(&dboptions);

  hash_init(&dboptions, lower_case_table_names ?

            &my_charset_bin : system_charset_info,

            32, 0, 0, (hash_get_key) dboptions_get_key,

            free_dbopt,0);

  pthread_rwlock_unlock(&LOCK_dboptions);

}

/*

  Find database options in the hash.

  DESCRIPTION

    Search a database options in the hash, usings its path.

    Fills "create" on success.

  RETURN VALUES

    0 on success.

    1 on error.

*/

static bool get_dbopt(const char *dbname, HA_CREATE_INFO *create)

{

  my_dbopt_t *opt;

  uint32_t length;

  bool error= true;

  length= (uint) strlen(dbname);

  pthread_rwlock_rdlock(&LOCK_dboptions);

  if ((opt= (my_dbopt_t*) hash_search(&dboptions, (unsigned char*) dbname, length)))

  {

    create->default_table_charset= opt->charset;

    error= true;

  }

  pthread_rwlock_unlock(&LOCK_dboptions);

  return error;

}

/*

  Writes database options into the hash.

  DESCRIPTION

    Inserts database options into the hash, or updates

    options if they are already in the hash.

  RETURN VALUES

    0 on success.

    1 on error.

*/

static bool put_dbopt(const char *dbname, HA_CREATE_INFO *create)

{

  my_dbopt_t *opt;

  uint32_t length;

  bool error= false;

  length= (uint) strlen(dbname);

  pthread_rwlock_wrlock(&LOCK_dboptions);

  if (!(opt= (my_dbopt_t*) hash_search(&dboptions, (unsigned char*) dbname, length)))

  {

    /* Options are not in the hash, insert them */

    char *tmp_name;

    if (!my_multi_malloc(MYF(MY_WME | MY_ZEROFILL),

                         &opt, (uint) sizeof(*opt), &tmp_name, (uint) length+1,

                         NULL))

    {

      error= true;

      goto end;

    }

    opt->name= tmp_name;

    strcpy(opt->name, dbname);

    opt->name_length= length;

    if ((error= my_hash_insert(&dboptions, (unsigned char*) opt)))

    {

      free(opt);

      goto end;

    }

  }

  /* Update / write options in hash */

  opt->charset= create->default_table_charset;

end:

  pthread_rwlock_unlock(&LOCK_dboptions);

  return(error);

}

/*

  Deletes database options from the hash.

*/

void del_dbopt(const char *path)

{

  my_dbopt_t *opt;

  pthread_rwlock_wrlock(&LOCK_dboptions);

  if ((opt= (my_dbopt_t *)hash_search(&dboptions, (const unsigned char*) path,

                                      strlen(path))))

    hash_delete(&dboptions, (unsigned char*) opt);

  pthread_rwlock_unlock(&LOCK_dboptions);

}

/*

  Create database options file:

  DESCRIPTION

    Currently database default charset is only stored there.

  RETURN VALUES

  0	ok

  1	Could not create file or write to it.  Error sent through my_error()

*/

static bool write_db_opt(Session *session, const char *path, const char *name, HA_CREATE_INFO *create)

{

  bool error= true;

  drizzle::Schema db;

  assert(name);

  if (!create->default_table_charset)

    create->default_table_charset= session->variables.collation_server;

  if (put_dbopt(path, create))

    return 1;

  db.set_name(name);

  db.set_characterset(create->default_table_charset->csname);

  db.set_collation(create->default_table_charset->name);

  fstream output(path, ios::out | ios::trunc | ios::binary);

  if (!db.SerializeToOstream(&output))

    error= false;

  return error;

}

/*

  Load database options file

  load_db_opt()

  path		Path for option file

  create	Where to store the read options

  DESCRIPTION

  RETURN VALUES

  0	File found

  1	No database file or could not open it

*/

bool load_db_opt(Session *session, const char *path, HA_CREATE_INFO *create)

{

  bool error=1;

  drizzle::Schema db;

  string buffer;

  memset(create, 0, sizeof(*create));

  create->default_table_charset= session->variables.collation_server;

  /* Check if options for this database are already in the hash */

  if (!get_dbopt(path, create))

    return(0);

  fstream input(path, ios::in | ios::binary);

  if (!input)

    goto err1;

  else if (!db.ParseFromIstream(&input))

    goto err1;

  buffer= db.characterset();

  if (!(create->default_table_charset= get_charset_by_csname(buffer.c_str(), MY_CS_PRIMARY, MYF(0))))

  {

    errmsg_printf(ERRMSG_LVL_ERROR, _("Error while loading database options: '%s':"),path);

    errmsg_printf(ERRMSG_LVL_ERROR, ER(ER_UNKNOWN_COLLATION), buffer.c_str());

    create->default_table_charset= default_charset_info;

  }

  buffer= db.collation();

  if (!(create->default_table_charset= get_charset_by_name(buffer.c_str(), MYF(0))))

  {

    errmsg_printf(ERRMSG_LVL_ERROR, _("Error while loading database options: '%s':"),path);

    errmsg_printf(ERRMSG_LVL_ERROR, ER(ER_UNKNOWN_COLLATION), buffer.c_str());

    create->default_table_charset= default_charset_info;

  }

  /*

    Put the loaded value into the hash.

    Note that another thread could've added the same

    entry to the hash after we called get_dbopt(),

    but it's not an error, as put_dbopt() takes this

    possibility into account.

  */

  error= put_dbopt(path, create);

err1:

  return(error);

}

/*

  Retrieve database options by name. Load database options file or fetch from

  cache.

  SYNOPSIS

    load_db_opt_by_name()

    db_name         Database name

    db_create_info  Where to store the database options

  DESCRIPTION

    load_db_opt_by_name() is a shortcut for load_db_opt().

  NOTE

    Although load_db_opt_by_name() (and load_db_opt()) returns status of

    the operation, it is useless usually and should be ignored. The problem

    is that there are 1) system databases ("mysql") and 2) virtual

    databases ("information_schema"), which do not contain options file.

    So, load_db_opt[_by_name]() returns false for these databases, but this

    is not an error.

    load_db_opt[_by_name]() clears db_create_info structure in any case, so

    even on failure it contains valid data. So, common use case is just

    call load_db_opt[_by_name]() without checking return value and use

    db_create_info right after that.

  RETURN VALUES (read NOTE!)

    false   Success

    true    Failed to retrieve options

*/

bool load_db_opt_by_name(Session *session, const char *db_name,

                         HA_CREATE_INFO *db_create_info)

{

  char db_opt_path[FN_REFLEN];

  /*

    Pass an empty file name, and the database options file name as extension

    to avoid table name to file name encoding.

  */

  (void) build_table_filename(db_opt_path, sizeof(db_opt_path),

                              db_name, "", MY_DB_OPT_FILE, 0);

  return load_db_opt(session, db_opt_path, db_create_info);

}

/**

  Return default database collation.

  @param session     Thread context.

  @param db_name Database name.

  @return CHARSET_INFO object. The operation always return valid character

    set, even if the database does not exist.

*/

const CHARSET_INFO *get_default_db_collation(Session *session, const char *db_name)

{

  HA_CREATE_INFO db_info;

  if (session->db != NULL && strcmp(db_name, session->db) == 0)

    return session->db_charset;

  load_db_opt_by_name(session, db_name, &db_info);

  /*

    NOTE: even if load_db_opt_by_name() fails,

    db_info.default_table_charset contains valid character set

    (collation_server). We should not fail if load_db_opt_by_name() fails,

    because it is valid case. If a database has been created just by

    "mkdir", it does not contain db.opt file, but it is valid database.

  */

  return db_info.default_table_charset;

}

/*

  Create a database

  SYNOPSIS

  mysql_create_db()

  session		Thread handler

  db		Name of database to create

		Function assumes that this is already validated.

  create_info	Database create options (like character set)

  silent	Used by replication when internally creating a database.

		In this case the entry should not be logged.

  SIDE-EFFECTS

   1. Report back to client that command succeeded (my_ok)

   2. Report errors to client

   3. Log event to binary log

   (The 'silent' flags turns off 1 and 3.)

  RETURN VALUES

  false ok

  true  Error

*/

int mysql_create_db(Session *session, char *db, HA_CREATE_INFO *create_info, bool silent)

{

  char	 path[FN_REFLEN+16];

  char	 tmp_query[FN_REFLEN+16];

  long result= 1;

  int error= 0;

  struct stat stat_info;

  uint32_t create_options= create_info ? create_info->options : 0;

  uint32_t path_len;

  /* do not create 'information_schema' db */

  if (!my_strcasecmp(system_charset_info, db, INFORMATION_SCHEMA_NAME.c_str()))

  {

    my_error(ER_DB_CREATE_EXISTS, MYF(0), db);

    return(-1);

  }

  /*

    Do not create database if another thread is holding read lock.

    Wait for global read lock before acquiring LOCK_drizzle_create_db.

    After wait_if_global_read_lock() we have protection against another

    global read lock. If we would acquire LOCK_drizzle_create_db first,

    another thread could step in and get the global read lock before we

    reach wait_if_global_read_lock(). If this thread tries the same as we

    (admin a db), it would then go and wait on LOCK_drizzle_create_db...

    Furthermore wait_if_global_read_lock() checks if the current thread

    has the global read lock and refuses the operation with

    ER_CANT_UPDATE_WITH_READLOCK if applicable.

  */

  if (wait_if_global_read_lock(session, 0, 1))

  {

    error= -1;

    goto exit2;

  }

  pthread_mutex_lock(&LOCK_drizzle_create_db);

  /* Check directory */

  path_len= build_table_filename(path, sizeof(path), db, "", "", 0);

  path[path_len-1]= 0;                    // Remove last '/' from path

  if (!stat(path,&stat_info))

  {

    if (!(create_options & HA_LEX_CREATE_IF_NOT_EXISTS))

    {

      my_error(ER_DB_CREATE_EXISTS, MYF(0), db);

      error= -1;

      goto exit;

    }

    push_warning_printf(session, DRIZZLE_ERROR::WARN_LEVEL_NOTE,

			ER_DB_CREATE_EXISTS, ER(ER_DB_CREATE_EXISTS), db);

    if (!silent)

      my_ok(session);

    error= 0;

    goto exit;

  }

  else

  {

    if (errno != ENOENT)

    {

      my_error(EE_STAT, MYF(0), path, errno);

      goto exit;

    }

    if (mkdir(path,0777) < 0)

    {

      my_error(ER_CANT_CREATE_DB, MYF(0), db, my_errno);

      error= -1;

      goto exit;

    }

  }

  path[path_len-1]= FN_LIBCHAR;

  strncpy(path+path_len, MY_DB_OPT_FILE, sizeof(path)-path_len-1);

  if (write_db_opt(session, path, db, create_info))

  {

    /*

      Could not create options file.

      Restore things to beginning.

    */

    path[path_len]= 0;

    if (rmdir(path) >= 0)

    {

      error= -1;

      goto exit;

    }

    /*

      We come here when we managed to create the database, but not the option

      file.  In this case it's best to just continue as if nothing has

      happened.  (This is a very unlikely senario)

    */

  }

  if (!silent)

  {

    char *query;

    uint32_t query_length;

    if (!session->query)				// Only in replication

    {

      query= tmp_query;

      query_length= sprintf(tmp_query, "create database `%s`", db);

    }

    else

    {

      query= 	    session->query;

      query_length= session->query_length;

    }

    if (drizzle_bin_log.is_open())

    {

      Query_log_event qinfo(session, query, query_length, 0,

			    /* suppress_use */ true);

      /*

	Write should use the database being created as the "current

        database" and not the threads current database, which is the

        default. If we do not change the "current database" to the

        database being created, the CREATE statement will not be

        replicated when using --binlog-do-db to select databases to be

        replicated.

	An example (--binlog-do-db=sisyfos):

          CREATE DATABASE bob;        # Not replicated

          USE bob;                    # 'bob' is the current database

          CREATE DATABASE sisyfos;    # Not replicated since 'bob' is

                                      # current database.

          USE sisyfos;                # Will give error on slave since

                                      # database does not exist.

      */

      qinfo.db     = db;

      qinfo.db_len = strlen(db);

      /* These DDL methods and logging protected with LOCK_drizzle_create_db */

      drizzle_bin_log.write(&qinfo);

    }

    my_ok(session, result);

  }

exit:

  pthread_mutex_unlock(&LOCK_drizzle_create_db);

  start_waiting_global_read_lock(session);

exit2:

  return(error);

}

/* db-name is already validated when we come here */

bool mysql_alter_db(Session *session, const char *db, HA_CREATE_INFO *create_info)

{

  char path[FN_REFLEN+16];

  long result=1;

  int error= false;

  /*

    Do not alter database if another thread is holding read lock.

    Wait for global read lock before acquiring LOCK_drizzle_create_db.

    After wait_if_global_read_lock() we have protection against another

    global read lock. If we would acquire LOCK_drizzle_create_db first,

    another thread could step in and get the global read lock before we

    reach wait_if_global_read_lock(). If this thread tries the same as we

    (admin a db), it would then go and wait on LOCK_drizzle_create_db...

    Furthermore wait_if_global_read_lock() checks if the current thread

    has the global read lock and refuses the operation with

    ER_CANT_UPDATE_WITH_READLOCK if applicable.

  */

  if ((error=wait_if_global_read_lock(session,0,1)))

    goto exit2;

  pthread_mutex_lock(&LOCK_drizzle_create_db);

  /*

     Recreate db options file: /dbpath/.db.opt

     We pass MY_DB_OPT_FILE as "extension" to avoid

     "table name to file name" encoding.

  */

  build_table_filename(path, sizeof(path), db, "", MY_DB_OPT_FILE, 0);

  if ((error=write_db_opt(session, path, db, create_info)))

    goto exit;

  /* Change options if current database is being altered. */

  if (session->db && !strcmp(session->db,db))

  {

    session->db_charset= create_info->default_table_charset ?

		     create_info->default_table_charset :

		     session->variables.collation_server;

    session->variables.collation_database= session->db_charset;

  }