open.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:14k
- /* 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 */
- /* open a isam-database */
- #include "isamdef.h"
- #if defined(MSDOS) || defined(__WIN__)
- #ifdef __WIN__
- #include <fcntl.h>
- #else
- #include <process.h> /* Prototype for getpid */
- #endif
- #endif
- #ifdef VMS
- #include "static.c"
- #endif
- static void setup_functions(ISAM_SHARE *info);
- static void setup_key_functions(N_KEYDEF *keyinfo);
- #define get_next_element(to,pos,size) { memcpy((char*) to,pos,(size_t) size);
- pos+=size;}
- /******************************************************************************
- ** Return the shared struct if the table is already open.
- ** In MySQL the server will handle version issues.
- ******************************************************************************/
- static N_INFO *test_if_reopen(char *filename)
- {
- LIST *pos;
- for (pos=nisam_open_list ; pos ; pos=pos->next)
- {
- N_INFO *info=(N_INFO*) pos->data;
- ISAM_SHARE *share=info->s;
- if (!strcmp(share->filename,filename) && share->last_version)
- return info;
- }
- return 0;
- }
- /******************************************************************************
- open a isam database.
- By default exit with error if database is locked
- if handle_locking & HA_OPEN_WAIT_IF_LOCKED then wait if database is locked
- if handle_locking & HA_OPEN_IGNORE_IF_LOCKED then continue, but count-vars
- in st_i_info may be wrong. count-vars are automaticly fixed after next
- isam request.
- ******************************************************************************/
- N_INFO *nisam_open(const char *name, int mode, uint handle_locking)
- {
- int lock_error,kfile,open_mode,save_errno;
- uint i,j,len,errpos,head_length,base_pos,offset,info_length,extra;
- char name_buff[FN_REFLEN],*disk_cache,*disk_pos;
- N_INFO info,*m_info,*old_info;
- ISAM_SHARE share_buff,*share;
- DBUG_ENTER("nisam_open");
- LINT_INIT(m_info);
- kfile= -1;
- lock_error=1;
- errpos=0;
- head_length=sizeof(share_buff.state.header);
- bzero((byte*) &info,sizeof(info));
- VOID(fn_format(name_buff,name,"",N_NAME_IEXT,4+16+32));
- pthread_mutex_lock(&THR_LOCK_isam);
- if (!(old_info=test_if_reopen(name_buff)))
- {
- share= &share_buff;
- bzero((gptr) &share_buff,sizeof(share_buff));
- if ((kfile=my_open(name_buff,(open_mode=O_RDWR) | O_SHARE,MYF(0))) < 0)
- {
- if ((errno != EROFS && errno != EACCES) ||
- mode != O_RDONLY ||
- (kfile=my_open(name_buff,(open_mode=O_RDONLY) | O_SHARE,MYF(0))) < 0)
- goto err;
- }
- errpos=1;
- if (my_read(kfile,(char*) share->state.header.file_version,head_length,
- MYF(MY_NABP)))
- goto err;
- if (memcmp((byte*) share->state.header.file_version,
- (byte*) nisam_file_magic, 3) ||
- share->state.header.file_version[3] == 0 ||
- (uchar) share->state.header.file_version[3] > 3)
- {
- DBUG_PRINT("error",("Wrong header in %s",name_buff));
- DBUG_DUMP("error_dump",(char*) share->state.header.file_version,
- head_length);
- my_errno=HA_ERR_CRASHED;
- goto err;
- }
- if (uint2korr(share->state.header.options) &
- ~(HA_OPTION_PACK_RECORD | HA_OPTION_PACK_KEYS |
- HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA |
- HA_OPTION_TEMP_COMPRESS_RECORD))
- {
- DBUG_PRINT("error",("wrong options: 0x%lx",
- uint2korr(share->state.header.options)));
- my_errno=HA_ERR_OLD_FILE;
- goto err;
- }
- info_length=uint2korr(share->state.header.header_length);
- base_pos=uint2korr(share->state.header.base_pos);
- if (!(disk_cache=(char*) my_alloca(info_length)))
- {
- my_errno=ENOMEM;
- goto err;
- }
- errpos=2;
- VOID(my_seek(kfile,0L,MY_SEEK_SET,MYF(0)));
- #ifndef NO_LOCKING
- if (!(handle_locking & HA_OPEN_TMP_TABLE))
- {
- if ((lock_error=my_lock(kfile,F_RDLCK,0L,F_TO_EOF,
- MYF(handle_locking & HA_OPEN_WAIT_IF_LOCKED ?
- 0 : MY_DONT_WAIT))) &&
- !(handle_locking & HA_OPEN_IGNORE_IF_LOCKED))
- goto err;
- }
- #endif
- errpos=3;
- if (my_read(kfile,disk_cache,info_length,MYF(MY_NABP)))
- goto err;
- len=uint2korr(share->state.header.state_info_length);
- if (len != sizeof(N_STATE_INFO))
- {
- DBUG_PRINT("warning",
- ("saved_state_info_length: %d base_info_length: %d",
- len,sizeof(N_STATE_INFO)));
- }
- if (len > sizeof(N_STATE_INFO))
- len=sizeof(N_STATE_INFO);
- share->state_length=len;
- memcpy(&share->state.header.file_version[0],disk_cache,(size_t) len);
- len=uint2korr(share->state.header.base_info_length);
- if (len != sizeof(N_BASE_INFO))
- {
- DBUG_PRINT("warning",("saved_base_info_length: %d base_info_length: %d",
- len,sizeof(N_BASE_INFO)));
- if (len <= offsetof(N_BASE_INFO,sortkey))
- share->base.sortkey=(ushort) ~0;
- }
- memcpy((char*) (byte*) &share->base,disk_cache+base_pos,
- (size_t) min(len,sizeof(N_BASE_INFO)));
- disk_pos=disk_cache+base_pos+len;
- share->base.options=uint2korr(share->state.header.options);
- if (share->base.max_key_length > N_MAX_KEY_BUFF)
- {
- my_errno=HA_ERR_UNSUPPORTED;
- goto err;
- }
- if (share->base.options & HA_OPTION_COMPRESS_RECORD)
- share->base.max_key_length+=2; /* For safety */
- if (!my_multi_malloc(MY_WME,
- &share,sizeof(*share),
- &share->keyinfo,share->base.keys*sizeof(N_KEYDEF),
- &share->rec,(share->base.fields+1)*sizeof(N_RECINFO),
- &share->blobs,sizeof(N_BLOB)*share->base.blobs,
- &share->filename,strlen(name_buff)+1,
- NullS))
- goto err;
- errpos=4;
- *share=share_buff;
- strmov(share->filename,name_buff);
- /* Fix key in used if old nisam-database */
- if (share->state_length <= offsetof(N_STATE_INFO,keys))
- share->state.keys=share->base.keys;
- share->blocksize=min(IO_SIZE,nisam_block_size);
- for (i=0 ; i < share->base.keys ; i++)
- {
- get_next_element(&share->keyinfo[i].base,disk_pos,sizeof(N_SAVE_KEYDEF));
- setup_key_functions(share->keyinfo+i);
- set_if_smaller(share->blocksize,share->keyinfo[i].base.block_length);
- for (j=0 ; j <= share->keyinfo[i].base.keysegs ; j++)
- {
- get_next_element(&share->keyinfo[i].seg[j],disk_pos,
- sizeof(N_SAVE_KEYSEG));
- }
- }
- if (!share->blocksize)
- {
- my_errno=HA_ERR_CRASHED;
- goto err;
- }
- for (i=j=offset=0 ; i < share->base.fields ; i++)
- {
- get_next_element(&share->rec[i].base,disk_pos,sizeof(N_SAVE_RECINFO));
- #ifndef NOT_PACKED_DATABASES
- share->rec[i].pack_type=0;
- share->rec[i].huff_tree=0;
- #endif
- if (share->rec[i].base.type == (int) FIELD_BLOB)
- {
- share->blobs[j].pack_length=share->rec[i].base.length;
- share->blobs[j].offset=offset;
- j++;
- offset+=sizeof(char*);
- }
- offset+=share->rec[i].base.length;
- }
- share->rec[i].base.type=(int) FIELD_LAST;
- #ifndef NO_LOCKING
- if (! lock_error)
- {
- VOID(my_lock(kfile,F_UNLCK,0L,F_TO_EOF,MYF(MY_SEEK_NOT_DONE)));
- lock_error=1; /* Database unlocked */
- }
- #endif
- if ((info.dfile=my_open(fn_format(name_buff,name,"",N_NAME_DEXT,2+4),
- mode | O_SHARE,
- MYF(MY_WME))) < 0)
- goto err;
- errpos=5;
- share->kfile=kfile;
- share->mode=open_mode;
- share->this_process=(ulong) getpid();
- share->rnd= (int) share->this_process; /* rnd-counter for splitts */
- #ifndef DBUG_OFF
- share->rnd=0; /* To make things repeatable */
- #endif
- share->last_process= share->state.process;
- if (!(share->last_version=share->state.version))
- share->last_version=1; /* Safety */
- share->rec_reflength=share->base.rec_reflength; /* May be changed */
- share->data_file_type=STATIC_RECORD;
- if (share->base.options & HA_OPTION_COMPRESS_RECORD)
- {
- share->data_file_type = COMPRESSED_RECORD;
- share->base.options|= HA_OPTION_READ_ONLY_DATA;
- info.s=share;
- if (_nisam_read_pack_info(&info,
- (pbool) test(!(share->base.options &
- (HA_OPTION_PACK_RECORD |
- HA_OPTION_TEMP_COMPRESS_RECORD)))))
- goto err;
- }
- else if (share->base.options & HA_OPTION_PACK_RECORD)
- share->data_file_type = DYNAMIC_RECORD;
- my_afree((gptr) disk_cache);
- setup_functions(share);
- #ifdef THREAD
- thr_lock_init(&share->lock);
- VOID(pthread_mutex_init(&share->intern_lock,MY_MUTEX_INIT_FAST));
- #endif
- }
- else
- {
- share= old_info->s;
- if (mode == O_RDWR && share->mode == O_RDONLY)
- {
- my_errno=EACCES; /* Can't open in write mode*/
- goto err;
- }
- if ((info.dfile=my_open(fn_format(name_buff,old_info->filename,"",
- N_NAME_DEXT,2+4),
- mode | O_SHARE,MYF(MY_WME))) < 0)
- {
- my_errno=errno;
- goto err;
- }
- errpos=5;
- }
- /* alloc and set up private structure parts */
- if (!my_multi_malloc(MY_WME,
- &m_info,sizeof(N_INFO),
- &info.blobs,sizeof(N_BLOB)*share->base.blobs,
- &info.buff,(share->base.max_block*2+
- share->base.max_key_length),
- &info.lastkey,share->base.max_key_length*3+1,
- &info.filename,strlen(name)+1,
- NullS))
- goto err;
- errpos=6;
- strmov(info.filename,name);
- memcpy(info.blobs,share->blobs,sizeof(N_BLOB)*share->base.blobs);
- info.s=share;
- info.lastpos= NI_POS_ERROR;
- info.update= (short) (HA_STATE_NEXT_FOUND+HA_STATE_PREV_FOUND);
- info.opt_flag=READ_CHECK_USED;
- info.alloced_rec_buff_length=share->base.pack_reclength;
- info.this_uniq= (ulong) info.dfile; /* Uniq number in process */
- info.this_loop=0; /* Update counter */
- info.last_uniq= share->state.uniq;
- info.last_loop= share->state.loop;
- info.options=share->base.options |
- (mode == O_RDONLY ? HA_OPTION_READ_ONLY_DATA : 0);
- info.lock_type=F_UNLCK;
- info.errkey= -1;
- pthread_mutex_lock(&share->intern_lock);
- info.read_record=share->read_record;
- share->reopen++;
- if (share->base.options & HA_OPTION_READ_ONLY_DATA)
- {
- info.lock_type=F_RDLCK;
- share->r_locks++;
- info.this_uniq=share->state.uniq; /* Row checksum */
- }
- #ifndef NO_LOCKING
- if (handle_locking & HA_OPEN_TMP_TABLE)
- #endif
- {
- share->w_locks++; /* We don't have to update status */
- info.lock_type=F_WRLCK;
- }
- pthread_mutex_unlock(&share->intern_lock);
- /* Allocate buffer for one record */
- extra=0;
- if (share->base.options & HA_OPTION_PACK_RECORD)
- extra=ALIGN_SIZE(MAX_DYN_BLOCK_HEADER)+N_SPLITT_LENGTH+
- DYN_DELETE_BLOCK_HEADER;
- if (!(info.rec_alloc=(byte*) my_malloc(share->base.pack_reclength+extra+
- 6,
- MYF(MY_WME | MY_ZEROFILL))))
- goto err;
- if (extra)
- info.rec_buff=info.rec_alloc+ALIGN_SIZE(MAX_DYN_BLOCK_HEADER);
- else
- info.rec_buff=info.rec_alloc;
- *m_info=info;
- #ifdef THREAD
- thr_lock_data_init(&share->lock,&m_info->lock,NULL);
- #endif
- m_info->open_list.data=(void*) m_info;
- nisam_open_list=list_add(nisam_open_list,&m_info->open_list);
- pthread_mutex_unlock(&THR_LOCK_isam);
- nisam_log_simple(LOG_OPEN,m_info,share->filename,
- (uint) strlen(share->filename));
- DBUG_RETURN(m_info);
- err:
- save_errno=my_errno ? my_errno : HA_ERR_END_OF_FILE;
- switch (errpos) {
- case 6:
- my_free((gptr) m_info,MYF(0));
- /* fall through */
- case 5:
- VOID(my_close(info.dfile,MYF(0)));
- if (old_info)
- break; /* Don't remove open table */
- /* fall through */
- case 4:
- my_free((gptr) share,MYF(0));
- /* fall through */
- case 3:
- #ifndef NO_LOCKING
- if (! lock_error)
- VOID(my_lock(kfile, F_UNLCK, 0L, F_TO_EOF, MYF(MY_SEEK_NOT_DONE)));
- #endif
- /* fall through */
- case 2:
- my_afree((gptr) disk_cache);
- /* fall through */
- case 1:
- VOID(my_close(kfile,MYF(0)));
- /* fall through */
- case 0:
- default:
- break;
- }
- pthread_mutex_unlock(&THR_LOCK_isam);
- my_errno=save_errno;
- DBUG_RETURN (NULL);
- } /* nisam_open */
- /* Set up functions in structs */
- static void setup_functions(register ISAM_SHARE *share)
- {
- if (share->base.options & HA_OPTION_COMPRESS_RECORD)
- {
- share->read_record=_nisam_read_pack_record;
- share->read_rnd=_nisam_read_rnd_pack_record;
- }
- else if (share->base.options & HA_OPTION_PACK_RECORD)
- {
- share->read_record=_nisam_read_dynamic_record;
- share->read_rnd=_nisam_read_rnd_dynamic_record;
- share->delete_record=_nisam_delete_dynamic_record;
- share->compare_record=_nisam_cmp_dynamic_record;
- /* add bits used to pack data to pack_reclength for faster allocation */
- share->base.pack_reclength+= share->base.pack_bits;
- if (share->base.blobs)
- {
- share->update_record=_nisam_update_blob_record;
- share->write_record=_nisam_write_blob_record;
- }
- else
- {
- share->write_record=_nisam_write_dynamic_record;
- share->update_record=_nisam_update_dynamic_record;
- }
- }
- else
- {
- share->read_record=_nisam_read_static_record;
- share->read_rnd=_nisam_read_rnd_static_record;
- share->delete_record=_nisam_delete_static_record;
- share->compare_record=_nisam_cmp_static_record;
- share->update_record=_nisam_update_static_record;
- share->write_record=_nisam_write_static_record;
- }
- return;
- }
- static void setup_key_functions(register N_KEYDEF *keyinfo)
- {
- if (keyinfo->base.flag & (HA_PACK_KEY | HA_SPACE_PACK_USED))
- {
- keyinfo->bin_search=_nisam_seq_search;
- keyinfo->get_key=_nisam_get_key;
- }
- else
- {
- keyinfo->bin_search=_nisam_bin_search;
- keyinfo->get_key=_nisam_get_static_key;
- }
- return;
- }
- /*
- Calculate a long checksum for a memoryblock. Used to verify pack_isam
- SYNOPSIS
- checksum()
- mem Pointer to memory block
- count Count of bytes
- */
- ulong _nisam_checksum(const byte *mem, uint count)
- {
- ulong crc;
- for (crc= 0; count-- ; mem++)
- crc= ((crc << 1) + *((uchar*) mem)) +
- test(crc & ((ulong) 1L << (8*sizeof(ulong)-1)));
- return crc;
- }