diff options
Diffstat (limited to 'storage/myisam/mi_dynrec.c')
| -rw-r--r-- | storage/myisam/mi_dynrec.c | 2030 |
1 files changed, 2030 insertions, 0 deletions
diff --git a/storage/myisam/mi_dynrec.c b/storage/myisam/mi_dynrec.c new file mode 100644 index 00000000..09c10040 --- /dev/null +++ b/storage/myisam/mi_dynrec.c @@ -0,0 +1,2030 @@ +/* + Copyright (c) 2000, 2011, 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 02110-1335 USA */ + +/* + Functions to handle space-packed-records and blobs + + A row may be stored in one or more linked blocks. + The block size is between MI_MIN_BLOCK_LENGTH and MI_MAX_BLOCK_LENGTH. + Each block is aligned on MI_DYN_ALIGN_SIZE. + The reson for the max block size is to not have too many different types + of blocks. For the differnet block types, look at _mi_get_block_info() +*/ + +#include "myisamdef.h" + +/* Enough for comparing if number is zero */ +static char zero_string[]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; + +static int write_dynamic_record(MI_INFO *info,const uchar *record, + ulong reclength); +static int _mi_find_writepos(MI_INFO *info,ulong reclength,my_off_t *filepos, + ulong *length); +static int update_dynamic_record(MI_INFO *info,my_off_t filepos,uchar *record, + ulong reclength); +static int delete_dynamic_record(MI_INFO *info,my_off_t filepos, + uint second_read); +static int _mi_cmp_buffer(File file, const uchar *buff, my_off_t filepos, + uint length); + +/* Play it safe; We have a small stack when using threads */ +#undef my_alloca +#undef my_afree +#define my_alloca(A) my_malloc(PSI_NOT_INSTRUMENTED, (A),MYF(0)) +#define my_afree(A) my_free((A)) + + /* Interface function from MI_INFO */ + +#ifdef HAVE_MMAP + +/* + Create mmaped area for MyISAM handler + + SYNOPSIS + mi_dynmap_file() + info MyISAM handler + + RETURN + 0 ok + 1 error. +*/ + +my_bool mi_dynmap_file(MI_INFO *info, my_off_t size) +{ + DBUG_ENTER("mi_dynmap_file"); + if (size == 0 || size > (my_off_t) (~((size_t) 0))) + { + if (size) + DBUG_PRINT("warning", ("File is too large for mmap")); + else + DBUG_PRINT("warning", ("Do not mmap zero-length")); + DBUG_RETURN(1); + } + /* + I wonder if it is good to use MAP_NORESERVE. From the Linux man page: + MAP_NORESERVE + Do not reserve swap space for this mapping. When swap space is + reserved, one has the guarantee that it is possible to modify the + mapping. When swap space is not reserved one might get SIGSEGV + upon a write if no physical memory is available. + */ + info->s->file_map= (uchar*) + my_mmap(0, (size_t) size, + info->s->mode==O_RDONLY ? PROT_READ : + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_NORESERVE, + info->dfile, 0L); + if (info->s->file_map == (uchar*) MAP_FAILED) + { + info->s->file_map= NULL; + DBUG_RETURN(1); + } +#if defined(HAVE_MADVISE) + madvise((char*) info->s->file_map, size, MADV_RANDOM); +#endif + info->s->mmaped_length= (size_t) size; + info->s->file_read= mi_mmap_pread; + info->s->file_write= mi_mmap_pwrite; + DBUG_RETURN(0); +} + + +/* + Destroy mmaped area for MyISAM handler + + SYNOPSIS + mi_munmap_file() + info MyISAM handler + + RETURN + 0 ok + !0 error. +*/ + +int mi_munmap_file(MI_INFO *info) +{ + int ret; + DBUG_ENTER("mi_unmap_file"); + if ((ret= my_munmap((void*) info->s->file_map, info->s->mmaped_length))) + DBUG_RETURN(ret); + info->s->file_read= mi_nommap_pread; + info->s->file_write= mi_nommap_pwrite; + info->s->file_map= 0; + info->s->mmaped_length= 0; + DBUG_RETURN(0); +} + + +/* + Resize mmaped area for MyISAM handler + + SYNOPSIS + mi_remap_file() + info MyISAM handler + + RETURN +*/ + +void mi_remap_file(MI_INFO *info, my_off_t size) +{ + if (info->s->file_map) + { + mi_munmap_file(info); + mi_dynmap_file(info, size); + } +} +#endif + + +/* + Read bytes from MySAM handler, using mmap or pread + + SYNOPSIS + mi_mmap_pread() + info MyISAM handler + Buffer Input buffer + Count Count of bytes for read + offset Start position + MyFlags + + RETURN + 0 ok +*/ + +size_t mi_mmap_pread(MI_INFO *info, uchar *Buffer, + size_t Count, my_off_t offset, myf MyFlags) +{ + DBUG_PRINT("info", ("mi_read with mmap %d\n", info->dfile)); + if (info->s->concurrent_insert) + mysql_rwlock_rdlock(&info->s->mmap_lock); + + /* + The following test may fail in the following cases: + - We failed to remap a memory area (fragmented memory?) + - This thread has done some writes, but not yet extended the + memory mapped area. + */ + + if (info->s->mmaped_length >= offset + Count) + { + memcpy(Buffer, info->s->file_map + offset, Count); + if (info->s->concurrent_insert) + mysql_rwlock_unlock(&info->s->mmap_lock); + return 0; + } + else + { + if (info->s->concurrent_insert) + mysql_rwlock_unlock(&info->s->mmap_lock); + return mysql_file_pread(info->dfile, Buffer, Count, offset, MyFlags); + } +} + + + /* wrapper for mysql_file_pread in case if mmap isn't used */ + +size_t mi_nommap_pread(MI_INFO *info, uchar *Buffer, + size_t Count, my_off_t offset, myf MyFlags) +{ + return mysql_file_pread(info->dfile, Buffer, Count, offset, MyFlags); +} + + +/* + Write bytes to MySAM handler, using mmap or pwrite + + SYNOPSIS + mi_mmap_pwrite() + info MyISAM handler + Buffer Output buffer + Count Count of bytes for write + offset Start position + MyFlags + + RETURN + 0 ok + !=0 error. In this case return error from pwrite +*/ + +size_t mi_mmap_pwrite(MI_INFO *info, const uchar *Buffer, + size_t Count, my_off_t offset, myf MyFlags) +{ + DBUG_PRINT("info", ("mi_write with mmap %d\n", info->dfile)); + if (info->s->concurrent_insert) + mysql_rwlock_rdlock(&info->s->mmap_lock); + + /* + The following test may fail in the following cases: + - We failed to remap a memory area (fragmented memory?) + - This thread has done some writes, but not yet extended the + memory mapped area. + */ + + if (info->s->mmaped_length >= offset + Count) + { + memcpy(info->s->file_map + offset, Buffer, Count); + if (info->s->concurrent_insert) + mysql_rwlock_unlock(&info->s->mmap_lock); + return 0; + } + else + { + info->s->nonmmaped_inserts++; + if (info->s->concurrent_insert) + mysql_rwlock_unlock(&info->s->mmap_lock); + return mysql_file_pwrite(info->dfile, Buffer, Count, offset, MyFlags); + } + +} + + + /* wrapper for mysql_file_pwrite in case if mmap isn't used */ + +size_t mi_nommap_pwrite(MI_INFO *info, const uchar *Buffer, + size_t Count, my_off_t offset, myf MyFlags) +{ + return mysql_file_pwrite(info->dfile, Buffer, Count, offset, MyFlags); +} + + +int _mi_write_dynamic_record(MI_INFO *info, const uchar *record) +{ + ulong reclength=_mi_rec_pack(info,info->rec_buff,record); + return (write_dynamic_record(info,info->rec_buff,reclength)); +} + +int _mi_update_dynamic_record(MI_INFO *info, my_off_t pos, const uchar *record) +{ + uint length=_mi_rec_pack(info,info->rec_buff,record); + return (update_dynamic_record(info,pos,info->rec_buff,length)); +} + +int _mi_write_blob_record(MI_INFO *info, const uchar *record) +{ + uchar *rec_buff; + int error; + ulong reclength,reclength2,extra; + + extra= (ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER)+MI_SPLIT_LENGTH+ + MI_DYN_DELETE_BLOCK_HEADER+1); + reclength= (info->s->base.pack_reclength + + _mi_calc_total_blob_length(info,record)+ extra); + if (!(rec_buff=(uchar*) my_alloca(reclength))) + { + my_errno= HA_ERR_OUT_OF_MEM; /* purecov: inspected */ + return(-1); + } + reclength2= _mi_rec_pack(info,rec_buff+ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER), + record); + DBUG_PRINT("info",("reclength: %lu reclength2: %lu", + reclength, reclength2)); + DBUG_ASSERT(reclength2 <= reclength); + error=write_dynamic_record(info,rec_buff+ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER), + reclength2); + my_afree(rec_buff); + return(error); +} + + +int _mi_update_blob_record(MI_INFO *info, my_off_t pos, const uchar *record) +{ + uchar *rec_buff; + int error; + ulong reclength,extra; + + extra= (ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER)+MI_SPLIT_LENGTH+ + MI_DYN_DELETE_BLOCK_HEADER); + reclength= (info->s->base.pack_reclength+ + _mi_calc_total_blob_length(info,record)+ extra); + if (!(rec_buff=(uchar*) my_alloca(reclength))) + { + my_errno= HA_ERR_OUT_OF_MEM; /* purecov: inspected */ + return(-1); + } + reclength=_mi_rec_pack(info,rec_buff+ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER), + record); + error=update_dynamic_record(info,pos, + rec_buff+ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER), + reclength); + my_afree(rec_buff); + return(error); +} + + +int _mi_delete_dynamic_record(MI_INFO *info) +{ + return delete_dynamic_record(info,info->lastpos,0); +} + + + /* Write record to data-file */ + +static int write_dynamic_record(MI_INFO *info, const uchar *record, + ulong reclength) +{ + int flag; + ulong length; + my_off_t filepos; + DBUG_ENTER("write_dynamic_record"); + + flag=0; + + /* + Check if we have enough room for the new record. + First we do simplified check to make usual case faster. + Then we do more precise check for the space left. + Though it still is not absolutely precise, as + we always use MI_MAX_DYN_BLOCK_HEADER while it can be + less in the most of the cases. + */ + + if (unlikely(info->s->base.max_data_file_length - + info->state->data_file_length < + reclength + MI_MAX_DYN_BLOCK_HEADER)) + { + if (info->s->base.max_data_file_length - info->state->data_file_length + + info->state->empty - info->state->del * MI_MAX_DYN_BLOCK_HEADER < + reclength + MI_MAX_DYN_BLOCK_HEADER) + { + my_errno=HA_ERR_RECORD_FILE_FULL; + DBUG_RETURN(1); + } + } + + do + { + if (_mi_find_writepos(info,reclength,&filepos,&length)) + goto err; + if (_mi_write_part_record(info,filepos,length, + (info->append_insert_at_end ? + HA_OFFSET_ERROR : info->s->state.dellink), + (uchar**) &record,&reclength,&flag)) + goto err; + } while (reclength); + + DBUG_RETURN(0); +err: + DBUG_RETURN(1); +} + + + /* Get a block for data ; The given data-area must be used !! */ + +static int _mi_find_writepos(MI_INFO *info, + ulong reclength, /* record length */ + my_off_t *filepos, /* Return file pos */ + ulong *length) /* length of block at filepos */ +{ + MI_BLOCK_INFO block_info; + ulong tmp; + DBUG_ENTER("_mi_find_writepos"); + + if (info->s->state.dellink != HA_OFFSET_ERROR && + !info->append_insert_at_end) + { + /* Deleted blocks exists; Get last used block */ + *filepos=info->s->state.dellink; + block_info.second_read=0; + info->rec_cache.seek_not_done=1; + if (!(_mi_get_block_info(&block_info,info->dfile,info->s->state.dellink) & + BLOCK_DELETED)) + { + DBUG_PRINT("error",("Delete link crashed")); + my_errno=HA_ERR_WRONG_IN_RECORD; + DBUG_RETURN(-1); + } + info->s->state.dellink=block_info.next_filepos; + info->state->del--; + info->state->empty-= block_info.block_len; + *length= block_info.block_len; + } + else + { + /* No deleted blocks; Allocate a new block */ + *filepos=info->state->data_file_length; + if ((tmp= reclength + 3 + MY_TEST(reclength >= (65520 - 3))) < + info->s->base.min_block_length) + tmp= info->s->base.min_block_length; + else + tmp= ((tmp+MI_DYN_ALIGN_SIZE-1) & + (~ (ulong) (MI_DYN_ALIGN_SIZE-1))); + if (info->state->data_file_length > + (info->s->base.max_data_file_length - tmp)) + { + my_errno=HA_ERR_RECORD_FILE_FULL; + DBUG_RETURN(-1); + } + if (tmp > MI_MAX_BLOCK_LENGTH) + tmp=MI_MAX_BLOCK_LENGTH; + *length= tmp; + info->state->data_file_length+= tmp; + info->s->state.split++; + info->update|=HA_STATE_WRITE_AT_END; + } + DBUG_RETURN(0); +} /* _mi_find_writepos */ + + + +/* + Unlink a deleted block from the deleted list. + This block will be combined with the preceding or next block to form + a big block. +*/ + +static my_bool unlink_deleted_block(MI_INFO *info, MI_BLOCK_INFO *block_info) +{ + DBUG_ENTER("unlink_deleted_block"); + if (block_info->filepos == info->s->state.dellink) + { + /* First deleted block; We can just use this ! */ + info->s->state.dellink=block_info->next_filepos; + } + else + { + MI_BLOCK_INFO tmp; + tmp.second_read=0; + /* Unlink block from the previous block */ + if (!(_mi_get_block_info(&tmp,info->dfile,block_info->prev_filepos) + & BLOCK_DELETED)) + DBUG_RETURN(1); /* Something is wrong */ + mi_sizestore(tmp.header+4,block_info->next_filepos); + if (info->s->file_write(info, tmp.header+4,8, + block_info->prev_filepos+4, MYF(MY_NABP))) + DBUG_RETURN(1); + /* Unlink block from next block */ + if (block_info->next_filepos != HA_OFFSET_ERROR) + { + if (!(_mi_get_block_info(&tmp,info->dfile,block_info->next_filepos) + & BLOCK_DELETED)) + DBUG_RETURN(1); /* Something is wrong */ + mi_sizestore(tmp.header+12,block_info->prev_filepos); + if (info->s->file_write(info, tmp.header+12,8, + block_info->next_filepos+12, + MYF(MY_NABP))) + DBUG_RETURN(1); + } + } + /* We now have one less deleted block */ + info->state->del--; + info->state->empty-= block_info->block_len; + info->s->state.split--; + + /* + If this was a block that we where accessing through table scan + (mi_rrnd() or mi_scan(), then ensure that we skip over this block + when doing next mi_rrnd() or mi_scan(). + */ + if (info->nextpos == block_info->filepos) + info->nextpos+=block_info->block_len; + DBUG_RETURN(0); +} + + +/* + Add a backward link to delete block + + SYNOPSIS + update_backward_delete_link() + info MyISAM handler + delete_block Position to delete block to update. + If this is 'HA_OFFSET_ERROR', nothing will be done + filepos Position to block that 'delete_block' should point to + + RETURN + 0 ok + 1 error. In this case my_error is set. +*/ + +static int update_backward_delete_link(MI_INFO *info, my_off_t delete_block, + my_off_t filepos) +{ + MI_BLOCK_INFO block_info; + DBUG_ENTER("update_backward_delete_link"); + + if (delete_block != HA_OFFSET_ERROR) + { + block_info.second_read=0; + if (_mi_get_block_info(&block_info,info->dfile,delete_block) + & BLOCK_DELETED) + { + uchar buff[8]; + mi_sizestore(buff,filepos); + if (info->s->file_write(info,buff, 8, delete_block+12, MYF(MY_NABP))) + DBUG_RETURN(1); /* Error on write */ + } + else + { + my_errno=HA_ERR_WRONG_IN_RECORD; + DBUG_RETURN(1); /* Wrong delete link */ + } + } + DBUG_RETURN(0); +} + + /* Delete datarecord from database */ + /* info->rec_cache.seek_not_done is updated in cmp_record */ + +static int delete_dynamic_record(MI_INFO *info, my_off_t filepos, + uint second_read) +{ + uint length,b_type; + MI_BLOCK_INFO block_info,del_block; + int error; + my_bool remove_next_block; + DBUG_ENTER("delete_dynamic_record"); + + /* First add a link from the last block to the new one */ + error= update_backward_delete_link(info, info->s->state.dellink, filepos); + + block_info.second_read=second_read; + do + { + /* Remove block at 'filepos' */ + if ((b_type=_mi_get_block_info(&block_info,info->dfile,filepos)) + & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | + BLOCK_FATAL_ERROR) || + (length=(uint) (block_info.filepos-filepos) +block_info.block_len) < + MI_MIN_BLOCK_LENGTH) + { + my_errno=HA_ERR_WRONG_IN_RECORD; + DBUG_RETURN(1); + } + /* Check if next block is a delete block */ + del_block.second_read=0; + remove_next_block=0; + if (_mi_get_block_info(&del_block,info->dfile,filepos+length) & + BLOCK_DELETED && del_block.block_len+length < MI_DYN_MAX_BLOCK_LENGTH) + { + /* We can't remove this yet as this block may be the head block */ + remove_next_block=1; + length+=del_block.block_len; + } + + block_info.header[0]=0; + mi_int3store(block_info.header+1,length); + mi_sizestore(block_info.header+4,info->s->state.dellink); + if (b_type & BLOCK_LAST) + bfill(block_info.header+12,8,255); + else + mi_sizestore(block_info.header+12,block_info.next_filepos); + if (info->s->file_write(info,(uchar*) block_info.header,20,filepos, + MYF(MY_NABP))) + DBUG_RETURN(1); + info->s->state.dellink = filepos; + info->state->del++; + info->state->empty+=length; + filepos=block_info.next_filepos; + + /* Now it's safe to unlink the deleted block directly after this one */ + if (remove_next_block && unlink_deleted_block(info,&del_block)) + error=1; + } while (!(b_type & BLOCK_LAST)); + + DBUG_RETURN(error); +} + + + /* Write a block to datafile */ + +int _mi_write_part_record(MI_INFO *info, + my_off_t filepos, /* points at empty block */ + ulong length, /* length of block */ + my_off_t next_filepos,/* Next empty block */ + uchar **record, /* pointer to record ptr */ + ulong *reclength, /* length of *record */ + int *flag) /* *flag == 0 if header */ +{ + ulong head_length,res_length,extra_length,long_block,del_length; + uchar *pos,*record_end; + my_off_t next_delete_block; + uchar temp[MI_SPLIT_LENGTH+MI_DYN_DELETE_BLOCK_HEADER]; + DBUG_ENTER("_mi_write_part_record"); + + next_delete_block=HA_OFFSET_ERROR; + + res_length=extra_length=0; + if (length > *reclength + MI_SPLIT_LENGTH) + { /* Splitt big block */ + res_length=MY_ALIGN(length- *reclength - MI_EXTEND_BLOCK_LENGTH, + MI_DYN_ALIGN_SIZE); + length-= res_length; /* Use this for first part */ + } + long_block= (length < 65520L && *reclength < 65520L) ? 0 : 1; + if (length == *reclength+ 3 + long_block) + { + /* Block is exactly of the right length */ + temp[0]=(uchar) (1+ *flag)+(uchar) long_block; /* Flag is 0 or 6 */ + if (long_block) + { + mi_int3store(temp+1,*reclength); + head_length=4; + } + else + { + mi_int2store(temp+1,*reclength); + head_length=3; + } + } + else if (length-long_block < *reclength+4) + { /* To short block */ + if (next_filepos == HA_OFFSET_ERROR) + next_filepos= (info->s->state.dellink != HA_OFFSET_ERROR && + !info->append_insert_at_end ? + info->s->state.dellink : info->state->data_file_length); + if (*flag == 0) /* First block */ + { + if (*reclength > MI_MAX_BLOCK_LENGTH) + { + head_length= 16; + temp[0]=13; + mi_int4store(temp+1,*reclength); + mi_int3store(temp+5,length-head_length); + mi_sizestore((uchar*) temp+8,next_filepos); + } + else + { + head_length=5+8+long_block*2; + temp[0]=5+(uchar) long_block; + if (long_block) + { + mi_int3store(temp+1,*reclength); + mi_int3store(temp+4,length-head_length); + mi_sizestore((uchar*) temp+7,next_filepos); + } + else + { + mi_int2store(temp+1,*reclength); + mi_int2store(temp+3,length-head_length); + mi_sizestore((uchar*) temp+5,next_filepos); + } + } + } + else + { + head_length=3+8+long_block; + temp[0]=11+(uchar) long_block; + if (long_block) + { + mi_int3store(temp+1,length-head_length); + mi_sizestore((uchar*) temp+4,next_filepos); + } + else + { + mi_int2store(temp+1,length-head_length); + mi_sizestore((uchar*) temp+3,next_filepos); + } + } + } + else + { /* Block with empty info last */ + head_length=4+long_block; + extra_length= length- *reclength-head_length; + temp[0]= (uchar) (3+ *flag)+(uchar) long_block; /* 3,4 or 9,10 */ + if (long_block) + { + mi_int3store(temp+1,*reclength); + temp[4]= (uchar) (extra_length); + } + else + { + mi_int2store(temp+1,*reclength); + temp[3]= (uchar) (extra_length); + } + length= *reclength+head_length; /* Write only what is needed */ + } + DBUG_DUMP("header",(uchar*) temp,head_length); + + /* Make a long block for one write */ + record_end= *record+length-head_length; + del_length=(res_length ? MI_DYN_DELETE_BLOCK_HEADER : 0); + bmove((uchar*) (*record-head_length),(uchar*) temp,head_length); + memcpy(temp,record_end,(size_t) (extra_length+del_length)); + bzero((uchar*) record_end,extra_length); + + if (res_length) + { + /* Check first if we can join this block with the next one */ + MI_BLOCK_INFO del_block; + my_off_t next_block=filepos+length+extra_length+res_length; + + del_block.second_read=0; + if (next_block < info->state->data_file_length && + info->s->state.dellink != HA_OFFSET_ERROR) + { + if ((_mi_get_block_info(&del_block,info->dfile,next_block) + & BLOCK_DELETED) && + res_length + del_block.block_len < MI_DYN_MAX_BLOCK_LENGTH) + { + if (unlink_deleted_block(info,&del_block)) + goto err; + res_length+=del_block.block_len; + } + } + + /* Create a delete link of the last part of the block */ + pos=record_end+extra_length; + pos[0]= '\0'; + mi_int3store(pos+1,res_length); + mi_sizestore(pos+4,info->s->state.dellink); + bfill(pos+12,8,255); /* End link */ + next_delete_block=info->s->state.dellink; + info->s->state.dellink= filepos+length+extra_length; + info->state->del++; + info->state->empty+=res_length; + info->s->state.split++; + } + if (info->opt_flag & WRITE_CACHE_USED && + info->update & HA_STATE_WRITE_AT_END) + { + if (info->update & HA_STATE_EXTEND_BLOCK) + { + info->update&= ~HA_STATE_EXTEND_BLOCK; + if (my_block_write(&info->rec_cache,(uchar*) *record-head_length, + length+extra_length+del_length,filepos)) + goto err; + } + else if (my_b_write(&info->rec_cache,(uchar*) *record-head_length, + length+extra_length+del_length)) + goto err; + } + else + { + info->rec_cache.seek_not_done=1; + if (info->s->file_write(info,(uchar*) *record-head_length,length+extra_length+ + del_length,filepos,info->s->write_flag)) + goto err; + } + memcpy(record_end,temp,(size_t) (extra_length+del_length)); + *record=record_end; + *reclength-=(length-head_length); + *flag=6; + + if (del_length) + { + /* link the next delete block to this */ + if (update_backward_delete_link(info, next_delete_block, + info->s->state.dellink)) + goto err; + } + + DBUG_RETURN(0); +err: + DBUG_PRINT("exit",("errno: %d",my_errno)); + DBUG_RETURN(1); +} /*_mi_write_part_record */ + + + /* update record from datafile */ + +static int update_dynamic_record(MI_INFO *info, my_off_t filepos, uchar *record, + ulong reclength) +{ + int flag; + uint error; + ulong length; + MI_BLOCK_INFO block_info; + DBUG_ENTER("update_dynamic_record"); + + flag=block_info.second_read=0; + /* + Check if we have enough room for the record. + First we do simplified check to make usual case faster. + Then we do more precise check for the space left. + Though it still is not absolutely precise, as + we always use MI_MAX_DYN_BLOCK_HEADER while it can be + less in the most of the cases. + */ + + /* + compare with just the reclength as we're going + to get some space from the old replaced record + */ + if (unlikely(info->s->base.max_data_file_length - + info->state->data_file_length < reclength)) + { + /* + let's read the old record's block to find out the length of the + old record + */ + if ((error=_mi_get_block_info(&block_info,info->dfile,filepos)) + & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | BLOCK_FATAL_ERROR)) + { + DBUG_PRINT("error",("Got wrong block info")); + if (!(error & BLOCK_FATAL_ERROR)) + my_errno=HA_ERR_WRONG_IN_RECORD; + goto err; + } + + /* + if new record isn't longer, we can go on safely + */ + if (block_info.rec_len < reclength) + { + if (info->s->base.max_data_file_length - info->state->data_file_length + + info->state->empty - info->state->del * MI_MAX_DYN_BLOCK_HEADER < + reclength - block_info.rec_len + MI_MAX_DYN_BLOCK_HEADER) + { + my_errno=HA_ERR_RECORD_FILE_FULL; + goto err; + } + } + block_info.second_read=0; + } + + while (reclength > 0) + { + if (filepos != info->s->state.dellink) + { + block_info.next_filepos= HA_OFFSET_ERROR; + if ((error=_mi_get_block_info(&block_info,info->dfile,filepos)) + & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | + BLOCK_FATAL_ERROR)) + { + DBUG_PRINT("error",("Got wrong block info")); + if (!(error & BLOCK_FATAL_ERROR)) + my_errno=HA_ERR_WRONG_IN_RECORD; + goto err; + } + length=(ulong) (block_info.filepos-filepos) + block_info.block_len; + if (length < reclength) + { + uint tmp=MY_ALIGN(reclength - length + 3 + + MY_TEST(reclength >= 65520L), MI_DYN_ALIGN_SIZE); + /* Don't create a block bigger than MI_MAX_BLOCK_LENGTH */ + tmp= MY_MIN(length+tmp, MI_MAX_BLOCK_LENGTH)-length; + /* Check if we can extend this block */ + if (block_info.filepos + block_info.block_len == + info->state->data_file_length && + info->state->data_file_length < + info->s->base.max_data_file_length-tmp) + { + /* extend file */ + DBUG_PRINT("info",("Extending file with %d bytes",tmp)); + if (info->nextpos == info->state->data_file_length) + info->nextpos+= tmp; + info->state->data_file_length+= tmp; + info->update|= HA_STATE_WRITE_AT_END | HA_STATE_EXTEND_BLOCK; + length+=tmp; + } + else if (length < MI_MAX_BLOCK_LENGTH - MI_MIN_BLOCK_LENGTH) + { + /* + Check if next block is a deleted block + Above we have MI_MIN_BLOCK_LENGTH to avoid the problem where + the next block is so small it can't be split which could + cause problems + */ + + MI_BLOCK_INFO del_block; + del_block.second_read=0; + if (_mi_get_block_info(&del_block,info->dfile, + block_info.filepos + block_info.block_len) & + BLOCK_DELETED) + { + /* Use; Unlink it and extend the current block */ + DBUG_PRINT("info",("Extending current block")); + if (unlink_deleted_block(info,&del_block)) + goto err; + if ((length+=del_block.block_len) > MI_MAX_BLOCK_LENGTH) + { + /* + New block was too big, link overflow part back to + delete list + */ + my_off_t next_pos; + ulong rest_length= length-MI_MAX_BLOCK_LENGTH; + set_if_bigger(rest_length, MI_MIN_BLOCK_LENGTH); + next_pos= del_block.filepos+ del_block.block_len - rest_length; + + if (update_backward_delete_link(info, info->s->state.dellink, + next_pos)) + DBUG_RETURN(1); + + /* create delete link for data that didn't fit into the page */ + del_block.header[0]=0; + mi_int3store(del_block.header+1, rest_length); + mi_sizestore(del_block.header+4,info->s->state.dellink); + bfill(del_block.header+12,8,255); + if (info->s->file_write(info,(uchar*) del_block.header,20, next_pos, + MYF(MY_NABP))) + DBUG_RETURN(1); + info->s->state.dellink= next_pos; + info->s->state.split++; + info->state->del++; + info->state->empty+= rest_length; + length-= rest_length; + } + } + } + } + } + else + { + if (_mi_find_writepos(info,reclength,&filepos,&length)) + goto err; + } + if (_mi_write_part_record(info,filepos,length,block_info.next_filepos, + &record,&reclength,&flag)) + goto err; + if ((filepos=block_info.next_filepos) == HA_OFFSET_ERROR) + { + /* Start writing data on deleted blocks */ + filepos=info->s->state.dellink; + } + } + + if (block_info.next_filepos != HA_OFFSET_ERROR) + { + /* + delete_dynamic_record() may change data file position. + IO cache must be notified as it may still have cached + data, which has to be flushed later. + */ + info->rec_cache.seek_not_done= 1; + if (delete_dynamic_record(info,block_info.next_filepos,1)) + goto err; + } + DBUG_RETURN(0); +err: + DBUG_RETURN(1); +} + + + /* Pack a record. Return new reclength */ + +uint _mi_rec_pack(MI_INFO *info, register uchar *to, + register const uchar *from) +{ + uint length,new_length,flag,bit,i; + uchar *pos,*end,*startpos,*packpos; + enum en_fieldtype type; + reg3 MI_COLUMNDEF *rec; + MI_BLOB *blob; + DBUG_ENTER("_mi_rec_pack"); + + flag=0 ; bit=1; + startpos=packpos=to; to+= info->s->base.pack_bits; blob=info->blobs; + rec=info->s->rec; + + for (i=info->s->base.fields ; i-- > 0; from+= length,rec++) + { + length=(uint) rec->length; + if ((type = (enum en_fieldtype) rec->type) != FIELD_NORMAL) + { + if (type == FIELD_BLOB) + { + if (!blob->length) + flag|=bit; + else + { + char *temp_pos; + size_t tmp_length=length-portable_sizeof_char_ptr; + memcpy((uchar*) to,from,tmp_length); + memcpy(&temp_pos,from+tmp_length,sizeof(char*)); + memcpy(to+tmp_length,temp_pos,(size_t) blob->length); + to+=tmp_length+blob->length; + } + blob++; + } + else if (type == FIELD_SKIP_ZERO) + { + if (memcmp((uchar*) from,zero_string,length) == 0) + flag|=bit; + else + { + memcpy((uchar*) to,from,(size_t) length); to+=length; + } + } + else if (type == FIELD_SKIP_ENDSPACE || + type == FIELD_SKIP_PRESPACE) + { + pos= (uchar*) from; end= (uchar*) from + length; + if (type == FIELD_SKIP_ENDSPACE) + { /* Pack trailing spaces */ + while (end > from && *(end-1) == ' ') + end--; + } + else + { /* Pack pref-spaces */ + while (pos < end && *pos == ' ') + pos++; + } + new_length=(uint) (end-pos); + if (new_length + 1 + MY_TEST(rec->length > 255 && new_length > 127) + < length) + { + if (rec->length > 255 && new_length > 127) + { + to[0]= (uchar) ((new_length & 127) + 128); + to[1]= (uchar) (new_length >> 7); + to+=2; + } + else + *to++= (uchar) new_length; + memcpy((uchar*) to,pos,(size_t) new_length); to+=new_length; + flag|=bit; + } + else + { + memcpy(to,from,(size_t) length); to+=length; + } + } + else if (type == FIELD_VARCHAR) + { + uint pack_length= HA_VARCHAR_PACKLENGTH(rec->length -1); + uint tmp_length; + if (pack_length == 1) + { + tmp_length= (uint) *(uchar*) from; + *to++= *from; + } + else + { + tmp_length= uint2korr(from); + store_key_length_inc(to,tmp_length); + } + memcpy(to, from+pack_length,tmp_length); + to+= tmp_length; + continue; + } + else + { + memcpy(to,from,(size_t) length); to+=length; + continue; /* Normal field */ + } + if ((bit= bit << 1) >= 256) + { + *packpos++= (uchar) flag; + bit=1; flag=0; + } + } + else + { + memcpy(to,from,(size_t) length); to+=length; + } + } + if (bit != 1) + *packpos= (uchar) flag; + if (info->s->calc_checksum) + *to++= (uchar) info->checksum; + DBUG_PRINT("exit",("packed length: %d",(int) (to-startpos))); + DBUG_RETURN((uint) (to-startpos)); +} /* _mi_rec_pack */ + + + +/* + Check if a record was correctly packed. Used only by myisamchk + Returns 0 if record is ok. +*/ + +my_bool _mi_rec_check(MI_INFO *info,const uchar *record, uchar *rec_buff, + ulong packed_length, my_bool with_checksum) +{ + uint length,new_length,flag,bit,i; + uchar *pos,*end,*packpos,*to; + enum en_fieldtype type; + reg3 MI_COLUMNDEF *rec; + DBUG_ENTER("_mi_rec_check"); + + packpos=rec_buff; to= rec_buff+info->s->base.pack_bits; + rec=info->s->rec; + flag= *packpos; bit=1; + + for (i=info->s->base.fields ; i-- > 0; record+= length, rec++) + { + length=(uint) rec->length; + if ((type = (enum en_fieldtype) rec->type) != FIELD_NORMAL) + { + if (type == FIELD_BLOB) + { + uint blob_length= + _mi_calc_blob_length(length-portable_sizeof_char_ptr,record); + if (!blob_length && !(flag & bit)) + goto err; + if (blob_length) + to+=length - portable_sizeof_char_ptr+ blob_length; + } + else if (type == FIELD_SKIP_ZERO) + { + if (memcmp((uchar*) record,zero_string,length) == 0) + { + if (!(flag & bit)) + goto err; + } + else + to+=length; + } + else if (type == FIELD_SKIP_ENDSPACE || + type == FIELD_SKIP_PRESPACE) + { + pos= (uchar*) record; end= (uchar*) record + length; + if (type == FIELD_SKIP_ENDSPACE) + { /* Pack trailing spaces */ + while (end > record && *(end-1) == ' ') + end--; + } + else + { /* Pack pre-spaces */ + while (pos < end && *pos == ' ') + pos++; + } + new_length=(uint) (end-pos); + if (new_length + 1 + MY_TEST(rec->length > 255 && new_length > 127) + < length) + { + if (!(flag & bit)) + goto err; + if (rec->length > 255 && new_length > 127) + { + /* purecov: begin inspected */ + if (to[0] != (uchar) ((new_length & 127) + 128) || + to[1] != (uchar) (new_length >> 7)) + goto err; + to+=2; + /* purecov: end */ + } + else if (*to++ != (uchar) new_length) + goto err; + to+=new_length; + } + else + to+=length; + } + else if (type == FIELD_VARCHAR) + { + uint pack_length= HA_VARCHAR_PACKLENGTH(rec->length -1); + uint tmp_length; + if (pack_length == 1) + { + tmp_length= (uint) *(uchar*) record; + to+= 1+ tmp_length; + continue; + } + else + { + tmp_length= uint2korr(record); + to+= get_pack_length(tmp_length)+tmp_length; + } + continue; + } + else + { + to+=length; + continue; /* Normal field */ + } + if ((bit= bit << 1) >= 256) + { + flag= *++packpos; + bit=1; + } + } + else + to+= length; + } + if (packed_length != (uint) (to - rec_buff) + MY_TEST(info->s->calc_checksum) || + (bit != 1 && (flag & ~(bit - 1)))) + goto err; + if (with_checksum && ((uchar) info->checksum != (uchar) *to)) + { + DBUG_PRINT("error",("wrong checksum for row")); + goto err; + } + DBUG_RETURN(0); + +err: + DBUG_RETURN(1); +} + + + + /* Unpacks a record */ + /* Returns -1 and my_errno =HA_ERR_RECORD_DELETED if reclength isn't */ + /* right. Returns reclength (>0) if ok */ + +size_t _mi_rec_unpack(register MI_INFO *info, register uchar *to, uchar *from, + ulong found_length) +{ + uint flag,bit,length,rec_length,min_pack_length; + enum en_fieldtype type; + uchar *from_end,*to_end,*packpos; + reg3 MI_COLUMNDEF *rec,*end_field; + DBUG_ENTER("_mi_rec_unpack"); + + to_end=to + info->s->base.reclength; + from_end=from+found_length; + flag= (uchar) *from; bit=1; packpos=from; + if (found_length < info->s->base.min_pack_length) + goto err; + from+= info->s->base.pack_bits; + min_pack_length=info->s->base.min_pack_length - info->s->base.pack_bits; + + for (rec=info->s->rec , end_field=rec+info->s->base.fields ; + rec < end_field ; to+= rec_length, rec++) + { + rec_length=rec->length; + if ((type = (enum en_fieldtype) rec->type) != FIELD_NORMAL && + (type != FIELD_CHECK)) + { + if (type == FIELD_VARCHAR) + { + uint pack_length= HA_VARCHAR_PACKLENGTH(rec_length-1); + if (pack_length == 1) + { + length= (uint) *(uchar*) from; + if (length > rec_length-1) + goto err; + *to= *from++; + } + else + { + get_key_length(length, from); + if (length > rec_length-2) + goto err; + int2store(to,length); + } + if (from+length > from_end) + goto err; + memcpy(to+pack_length, from, length); + from+= length; + min_pack_length--; + continue; + } + if (flag & bit) + { + if (type == FIELD_BLOB || type == FIELD_SKIP_ZERO) + bzero((uchar*) to,rec_length); + else if (type == FIELD_SKIP_ENDSPACE || + type == FIELD_SKIP_PRESPACE) + { + if (rec->length > 255 && *from & 128) + { + if (from + 1 >= from_end) + goto err; + length= (*from & 127)+ ((uint) (uchar) *(from+1) << 7); from+=2; + } + else + { + if (from == from_end) + goto err; + length= (uchar) *from++; + } + min_pack_length--; + if (length >= rec_length || + min_pack_length + length > (uint) (from_end - from)) + goto err; + if (type == FIELD_SKIP_ENDSPACE) + { + memcpy(to,(uchar*) from,(size_t) length); + bfill((uchar*) to+length,rec_length-length,' '); + } + else + { + bfill((uchar*) to,rec_length-length,' '); + memcpy(to+rec_length-length,(uchar*) from,(size_t) length); + } + from+=length; + } + } + else if (type == FIELD_BLOB) + { + uint size_length=rec_length- portable_sizeof_char_ptr; + ulong blob_length=_mi_calc_blob_length(size_length,from); + ulong from_left= (ulong) (from_end - from); + if (from_left < size_length || + from_left - size_length < blob_length || + from_left - size_length - blob_length < min_pack_length) + goto err; + memcpy(to, from, (size_t) size_length); + from+=size_length; + memcpy(to+size_length, &from, sizeof(char*)); + from+=blob_length; + } + else + { + if (type == FIELD_SKIP_ENDSPACE || type == FIELD_SKIP_PRESPACE) + min_pack_length--; + if (min_pack_length + rec_length > (uint) (from_end - from)) + goto err; + memcpy(to,(uchar*) from,(size_t) rec_length); from+=rec_length; + } + if ((bit= bit << 1) >= 256) + { + flag= (uchar) *++packpos; bit=1; + } + } + else + { + if (min_pack_length > (uint) (from_end - from)) + goto err; + min_pack_length-=rec_length; + memcpy(to, (uchar*) from, (size_t) rec_length); + from+=rec_length; + } + } + if (info->s->calc_checksum) + from++; + if (to == to_end && from == from_end && (bit == 1 || !(flag & ~(bit-1)))) + DBUG_RETURN(found_length); + +err: + my_errno= HA_ERR_WRONG_IN_RECORD; + DBUG_PRINT("error",("to_end: %p -> %p from_end: %p -> %p", + to, to_end, from, from_end)); + DBUG_DUMP("from",(uchar*) info->rec_buff,info->s->base.min_pack_length); + DBUG_RETURN(MY_FILE_ERROR); +} /* _mi_rec_unpack */ + + + /* Calc length of blob. Update info in blobs->length */ + +ulong _mi_calc_total_blob_length(MI_INFO *info, const uchar *record) +{ + ulong length; + MI_BLOB *blob,*end; + + for (length=0, blob= info->blobs, end=blob+info->s->base.blobs ; + blob != end; + blob++) + { + blob->length=_mi_calc_blob_length(blob->pack_length,record + blob->offset); + length+=blob->length; + } + return length; +} + + +ulong _mi_calc_blob_length(uint length, const uchar *pos) +{ + switch (length) { + case 1: + return (uint) (uchar) *pos; + case 2: + return (uint) uint2korr(pos); + case 3: + return uint3korr(pos); + case 4: + return uint4korr(pos); + default: + break; + } + return 0; /* Impossible */ +} + + +void _mi_store_blob_length(uchar *pos,uint pack_length,uint length) +{ + switch (pack_length) { + case 1: + *pos= (uchar) length; + break; + case 2: + int2store(pos,length); + break; + case 3: + int3store(pos,length); + break; + case 4: + int4store(pos,length); + default: + break; + } + return; +} + + +/* + Read record from datafile. + + SYNOPSIS + _mi_read_dynamic_record() + info MI_INFO pointer to table. + filepos From where to read the record. + buf Destination for record. + + NOTE + + If a write buffer is active, it needs to be flushed if its contents + intersects with the record to read. We always check if the position + of the first byte of the write buffer is lower than the position + past the last byte to read. In theory this is also true if the write + buffer is completely below the read segment. That is, if there is no + intersection. But this case is unusual. We flush anyway. Only if the + first byte in the write buffer is above the last byte to read, we do + not flush. + + A dynamic record may need several reads. So this check must be done + before every read. Reading a dynamic record starts with reading the + block header. If the record does not fit into the free space of the + header, the block may be longer than the header. In this case a + second read is necessary. These one or two reads repeat for every + part of the record. + + RETURN + 0 OK + -1 Error +*/ + +int _mi_read_dynamic_record(MI_INFO *info, my_off_t filepos, uchar *buf) +{ + int block_of_record; + uint b_type,UNINIT_VAR(left_length); + uchar *UNINIT_VAR(to); + MI_BLOCK_INFO block_info; + File file; + DBUG_ENTER("mi_read_dynamic_record"); + + if (filepos != HA_OFFSET_ERROR) + { + file=info->dfile; + block_of_record= 0; /* First block of record is numbered as zero. */ + block_info.second_read= 0; + do + { + /* A corrupted table can have wrong pointers. (Bug# 19835) */ + if (filepos == HA_OFFSET_ERROR) + goto panic; + if (info->opt_flag & WRITE_CACHE_USED && + info->rec_cache.pos_in_file < filepos + MI_BLOCK_INFO_HEADER_LENGTH && + flush_io_cache(&info->rec_cache)) + goto err; + info->rec_cache.seek_not_done=1; + if ((b_type= _mi_get_block_info(&block_info, file, filepos)) + & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | + BLOCK_FATAL_ERROR)) + { + if (b_type & (BLOCK_SYNC_ERROR | BLOCK_DELETED)) + my_errno=HA_ERR_RECORD_DELETED; + goto err; + } + if (block_of_record++ == 0) /* First block */ + { + if (block_info.rec_len > (uint) info->s->base.max_pack_length) + goto panic; + if (info->s->base.blobs) + { + if (!(to=mi_alloc_rec_buff(info, block_info.rec_len, + &info->rec_buff))) + goto err; + } + else + to= info->rec_buff; + left_length=block_info.rec_len; + } + if (left_length < block_info.data_len || ! block_info.data_len) + goto panic; /* Wrong linked record */ + /* copy information that is already read */ + { + uint offset= (uint) (block_info.filepos - filepos); + uint prefetch_len= (sizeof(block_info.header) - offset); + filepos+= sizeof(block_info.header); + + if (prefetch_len > block_info.data_len) + prefetch_len= block_info.data_len; + if (prefetch_len) + { + memcpy((uchar*) to, block_info.header + offset, prefetch_len); + block_info.data_len-= prefetch_len; + left_length-= prefetch_len; + to+= prefetch_len; + } + } + /* read rest of record from file */ + if (block_info.data_len) + { + if (info->opt_flag & WRITE_CACHE_USED && + info->rec_cache.pos_in_file < filepos + block_info.data_len && + flush_io_cache(&info->rec_cache)) + goto err; + /* + What a pity that this method is not called 'file_pread' and that + there is no equivalent without seeking. We are at the right + position already. :( + */ + if (info->s->file_read(info, (uchar*) to, block_info.data_len, + filepos, MYF(MY_NABP))) + goto panic; + left_length-=block_info.data_len; + to+=block_info.data_len; + } + filepos= block_info.next_filepos; + } while (left_length); + + info->update|= HA_STATE_AKTIV; /* We have a aktive record */ + fast_mi_writeinfo(info); + DBUG_RETURN(_mi_rec_unpack(info,buf,info->rec_buff,block_info.rec_len) != + MY_FILE_ERROR ? 0 : -1); + } + fast_mi_writeinfo(info); + DBUG_RETURN(-1); /* Wrong data to read */ + +panic: + my_errno=HA_ERR_WRONG_IN_RECORD; +err: + (void) _mi_writeinfo(info,0); + DBUG_RETURN(-1); +} + + /* compare unique constraint between stored rows */ + +int _mi_cmp_dynamic_unique(MI_INFO *info, MI_UNIQUEDEF *def, + const uchar *record, my_off_t pos) +{ + uchar *rec_buff,*old_record; + int error; + DBUG_ENTER("_mi_cmp_dynamic_unique"); + + if (!(old_record=my_alloca(info->s->base.reclength))) + DBUG_RETURN(1); + + /* Don't let the compare destroy blobs that may be in use */ + rec_buff=info->rec_buff; + if (info->s->base.blobs) + info->rec_buff=0; + error=_mi_read_dynamic_record(info,pos,old_record); + if (!error) + error=mi_unique_comp(def, record, old_record, def->null_are_equal); + if (info->s->base.blobs) + { + my_free(mi_get_rec_buff_ptr(info, info->rec_buff)); + info->rec_buff=rec_buff; + } + my_afree(old_record); + DBUG_RETURN(error); +} + + + /* Compare of record one disk with packed record in memory */ + +int _mi_cmp_dynamic_record(register MI_INFO *info, register const uchar *record) +{ + uint flag,reclength,b_type; + my_off_t filepos; + uchar *buffer; + MI_BLOCK_INFO block_info; + DBUG_ENTER("_mi_cmp_dynamic_record"); + + if (info->opt_flag & WRITE_CACHE_USED) + { + info->update&= ~(HA_STATE_WRITE_AT_END | HA_STATE_EXTEND_BLOCK); + if (flush_io_cache(&info->rec_cache)) + DBUG_RETURN(-1); + } + info->rec_cache.seek_not_done=1; + + /* If nobody have touched the database we don't have to test rec */ + + buffer=info->rec_buff; + if ((info->opt_flag & READ_CHECK_USED)) + { /* If check isn't disabled */ + if (info->s->base.blobs) + { + if (!(buffer=(uchar*) my_alloca(info->s->base.pack_reclength+ + _mi_calc_total_blob_length(info,record)))) + DBUG_RETURN(-1); + } + reclength=_mi_rec_pack(info,buffer,record); + record= buffer; + + filepos=info->lastpos; + flag=block_info.second_read=0; + block_info.next_filepos=filepos; + while (reclength > 0) + { + if ((b_type=_mi_get_block_info(&block_info,info->dfile, + block_info.next_filepos)) + & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | + BLOCK_FATAL_ERROR)) + { + if (b_type & (BLOCK_SYNC_ERROR | BLOCK_DELETED)) + my_errno=HA_ERR_RECORD_CHANGED; + goto err; + } + if (flag == 0) /* First block */ + { + flag=1; + if (reclength != block_info.rec_len) + { + my_errno=HA_ERR_RECORD_CHANGED; + goto err; + } + } else if (reclength < block_info.data_len) + { + my_errno=HA_ERR_WRONG_IN_RECORD; + goto err; + } + reclength-=block_info.data_len; + if (_mi_cmp_buffer(info->dfile,record,block_info.filepos, + block_info.data_len)) + { + my_errno=HA_ERR_RECORD_CHANGED; + goto err; + } + flag=1; + record+=block_info.data_len; + } + } + my_errno=0; +err: + if (buffer != info->rec_buff) + my_afree((uchar*) buffer); + DBUG_RETURN(my_errno); +} + + + /* Compare file to buffert */ + +static int _mi_cmp_buffer(File file, const uchar *buff, my_off_t filepos, + uint length) +{ + uint next_length; + uchar temp_buff[IO_SIZE*2]; + DBUG_ENTER("_mi_cmp_buffer"); + + next_length= IO_SIZE*2 - (uint) (filepos & (IO_SIZE-1)); + + while (length > IO_SIZE*2) + { + if (mysql_file_pread(file, temp_buff, next_length, filepos, MYF(MY_NABP)) || + memcmp(buff, temp_buff, next_length)) + goto err; + filepos+=next_length; + buff+=next_length; + length-= next_length; + next_length=IO_SIZE*2; + } + if (mysql_file_pread(file, temp_buff, length, filepos, MYF(MY_NABP))) + goto err; + DBUG_RETURN(memcmp(buff,temp_buff,length)); +err: + DBUG_RETURN(1); +} + + +/* + Read record from datafile. + + SYNOPSIS + _mi_read_rnd_dynamic_record() + info MI_INFO pointer to table. + buf Destination for record. + filepos From where to read the record. + skip_deleted_blocks If to repeat reading until a non-deleted + record is found. + + NOTE + + If a write buffer is active, it needs to be flushed if its contents + intersects with the record to read. We always check if the position + of the first byte of the write buffer is lower than the position + past the last byte to read. In theory this is also true if the write + buffer is completely below the read segment. That is, if there is no + intersection. But this case is unusual. We flush anyway. Only if the + first byte in the write buffer is above the last byte to read, we do + not flush. + + A dynamic record may need several reads. So this check must be done + before every read. Reading a dynamic record starts with reading the + block header. If the record does not fit into the free space of the + header, the block may be longer than the header. In this case a + second read is necessary. These one or two reads repeat for every + part of the record. + + RETURN + 0 OK + != 0 Error +*/ + +int _mi_read_rnd_dynamic_record(MI_INFO *info, uchar *buf, + register my_off_t filepos, + my_bool skip_deleted_blocks) +{ + int block_of_record, info_read, save_errno; + uint left_len,b_type; + uchar *UNINIT_VAR(to); + MI_BLOCK_INFO block_info; + MYISAM_SHARE *share=info->s; + DBUG_ENTER("_mi_read_rnd_dynamic_record"); + + info_read=0; + + if (info->lock_type == F_UNLCK) + { +#ifndef UNSAFE_LOCKING + if (share->tot_locks == 0) + { + if (my_lock(share->kfile,F_RDLCK,0L,F_TO_EOF, + MYF(MY_SEEK_NOT_DONE) | info->lock_wait)) + DBUG_RETURN(my_errno); + } +#else + info->tmp_lock_type=F_RDLCK; +#endif + } + else + info_read=1; /* memory-keyinfoblock is ok */ + + block_of_record= 0; /* First block of record is numbered as zero. */ + block_info.second_read= 0; + left_len=1; + do + { + if (filepos >= info->state->data_file_length) + { + if (!info_read) + { /* Check if changed */ + info_read=1; + info->rec_cache.seek_not_done=1; + if (mi_state_info_read_dsk(share->kfile,&share->state,1)) + goto panic; + } + if (filepos >= info->state->data_file_length) + { + my_errno= HA_ERR_END_OF_FILE; + goto err; + } + } + if (info->opt_flag & READ_CACHE_USED) + { + if (_mi_read_cache(&info->rec_cache,(uchar*) block_info.header,filepos, + sizeof(block_info.header), + (!block_of_record && skip_deleted_blocks ? + READING_NEXT : 0) | READING_HEADER)) + goto panic; + b_type=_mi_get_block_info(&block_info,-1,filepos); + } + else + { + if (info->opt_flag & WRITE_CACHE_USED && + info->rec_cache.pos_in_file < filepos + MI_BLOCK_INFO_HEADER_LENGTH && + flush_io_cache(&info->rec_cache)) + DBUG_RETURN(my_errno); + info->rec_cache.seek_not_done=1; + b_type=_mi_get_block_info(&block_info,info->dfile,filepos); + } + + if (b_type & (BLOCK_DELETED | BLOCK_ERROR | BLOCK_SYNC_ERROR | + BLOCK_FATAL_ERROR)) + { + if ((b_type & (BLOCK_DELETED | BLOCK_SYNC_ERROR))) + { + if (skip_deleted_blocks) + { + filepos=block_info.filepos+block_info.block_len; + block_info.second_read=0; + continue; /* Search after next_record */ + } + /* + If we're not on the first block of a record and + the block is marked as deleted or out of sync, + something's gone wrong: the record is damaged. + */ + if (block_of_record != 0) + goto panic; + my_errno=HA_ERR_RECORD_DELETED; + info->lastpos=block_info.filepos; + info->nextpos=block_info.filepos+block_info.block_len; + } + goto err; + } + if (block_of_record == 0) /* First block */ + { + if (block_info.rec_len > (uint) share->base.max_pack_length) + goto panic; + info->lastpos=filepos; + if (share->base.blobs) + { + if (!(to= mi_alloc_rec_buff(info, block_info.rec_len, + &info->rec_buff))) + goto err; + } + else + to= info->rec_buff; + left_len=block_info.rec_len; + } + if (left_len < block_info.data_len) + goto panic; /* Wrong linked record */ + + /* copy information that is already read */ + { + uint offset=(uint) (block_info.filepos - filepos); + uint tmp_length= (sizeof(block_info.header) - offset); + filepos=block_info.filepos; + + if (tmp_length > block_info.data_len) + tmp_length= block_info.data_len; + if (tmp_length) + { + memcpy((uchar*) to, block_info.header+offset,tmp_length); + block_info.data_len-=tmp_length; + left_len-=tmp_length; + to+=tmp_length; + filepos+=tmp_length; + } + } + /* read rest of record from file */ + if (block_info.data_len) + { + if (info->opt_flag & READ_CACHE_USED) + { + if (_mi_read_cache(&info->rec_cache,(uchar*) to,filepos, + block_info.data_len, + (!block_of_record && skip_deleted_blocks) ? + READING_NEXT : 0)) + goto panic; + } + else + { + if (info->opt_flag & WRITE_CACHE_USED && + info->rec_cache.pos_in_file < + block_info.filepos + block_info.data_len && + flush_io_cache(&info->rec_cache)) + goto err; + /* mysql_file_seek(info->dfile, filepos, MY_SEEK_SET, MYF(0)); */ + if (mysql_file_read(info->dfile, (uchar*) to, block_info.data_len, + MYF(MY_NABP))) + { + if (my_errno == HA_ERR_FILE_TOO_SHORT) + my_errno= HA_ERR_WRONG_IN_RECORD; /* Unexpected end of file */ + goto err; + } + } + } + /* + Increment block-of-record counter. If it was the first block, + remember the position behind the block for the next call. + */ + if (block_of_record++ == 0) + { + info->nextpos= block_info.filepos + block_info.block_len; + skip_deleted_blocks= 0; + } + left_len-=block_info.data_len; + to+=block_info.data_len; + filepos=block_info.next_filepos; + } while (left_len); + + info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED; + fast_mi_writeinfo(info); + if (_mi_rec_unpack(info,buf,info->rec_buff,block_info.rec_len) != + MY_FILE_ERROR) + DBUG_RETURN(0); + DBUG_RETURN(my_errno); /* Wrong record */ + +panic: + my_errno=HA_ERR_WRONG_IN_RECORD; /* Something is fatal wrong */ +err: + save_errno=my_errno; + (void) _mi_writeinfo(info,0); + DBUG_RETURN(my_errno=save_errno); +} + + + /* Read and process header from a dynamic-record-file */ + +uint _mi_get_block_info(MI_BLOCK_INFO *info, File file, my_off_t filepos) +{ + uint return_val=0; + uchar *header=info->header; + + if (file >= 0) + { + /* + We do not use mysql_file_pread() here because we want to have the file + pointer set to the end of the header after this function. + mysql_file_pread() may leave the file pointer untouched. + */ + mysql_file_seek(file, filepos, MY_SEEK_SET, MYF(0)); + if (mysql_file_read(file, header, sizeof(info->header), MYF(0)) != + sizeof(info->header)) + goto err; + } + DBUG_DUMP("header",header,MI_BLOCK_INFO_HEADER_LENGTH); + if (info->second_read) + { + if (info->header[0] <= 6 || info->header[0] == 13) + return_val=BLOCK_SYNC_ERROR; + } + else + { + if (info->header[0] > 6 && info->header[0] != 13) + return_val=BLOCK_SYNC_ERROR; + } + info->next_filepos= HA_OFFSET_ERROR; /* Dummy if no next block */ + + switch (info->header[0]) { + case 0: + if ((info->block_len=(uint) mi_uint3korr(header+1)) < + MI_MIN_BLOCK_LENGTH || + (info->block_len & (MI_DYN_ALIGN_SIZE -1))) + goto err; + info->filepos=filepos; + info->next_filepos=mi_sizekorr(header+4); + info->prev_filepos=mi_sizekorr(header+12); +#if SIZEOF_OFF_T == 4 + if ((mi_uint4korr(header+4) != 0 && + (mi_uint4korr(header+4) != (ulong) ~0 || + info->next_filepos != (ulong) ~0)) || + (mi_uint4korr(header+12) != 0 && + (mi_uint4korr(header+12) != (ulong) ~0 || + info->prev_filepos != (ulong) ~0))) + goto err; +#endif + return return_val | BLOCK_DELETED; /* Deleted block */ + + case 1: + info->rec_len=info->data_len=info->block_len=mi_uint2korr(header+1); + info->filepos=filepos+3; + return return_val | BLOCK_FIRST | BLOCK_LAST; + case 2: + info->rec_len=info->data_len=info->block_len=mi_uint3korr(header+1); + info->filepos=filepos+4; + return return_val | BLOCK_FIRST | BLOCK_LAST; + + case 13: + info->rec_len=mi_uint4korr(header+1); + info->block_len=info->data_len=mi_uint3korr(header+5); + info->next_filepos=mi_sizekorr(header+8); + info->second_read=1; + info->filepos=filepos+16; + return return_val | BLOCK_FIRST; + + case 3: + info->rec_len=info->data_len=mi_uint2korr(header+1); + info->block_len=info->rec_len+ (uint) header[3]; + info->filepos=filepos+4; + return return_val | BLOCK_FIRST | BLOCK_LAST; + case 4: + info->rec_len=info->data_len=mi_uint3korr(header+1); + info->block_len=info->rec_len+ (uint) header[4]; + info->filepos=filepos+5; + return return_val | BLOCK_FIRST | BLOCK_LAST; + + case 5: + info->rec_len=mi_uint2korr(header+1); + info->block_len=info->data_len=mi_uint2korr(header+3); + info->next_filepos=mi_sizekorr(header+5); + info->second_read=1; + info->filepos=filepos+13; + return return_val | BLOCK_FIRST; + case 6: + info->rec_len=mi_uint3korr(header+1); + info->block_len=info->data_len=mi_uint3korr(header+4); + info->next_filepos=mi_sizekorr(header+7); + info->second_read=1; + info->filepos=filepos+15; + return return_val | BLOCK_FIRST; + + /* The following blocks are identical to 1-6 without rec_len */ + case 7: + info->data_len=info->block_len=mi_uint2korr(header+1); + info->filepos=filepos+3; + return return_val | BLOCK_LAST; + case 8: + info->data_len=info->block_len=mi_uint3korr(header+1); + info->filepos=filepos+4; + return return_val | BLOCK_LAST; + + case 9: + info->data_len=mi_uint2korr(header+1); + info->block_len=info->data_len+ (uint) header[3]; + info->filepos=filepos+4; + return return_val | BLOCK_LAST; + case 10: + info->data_len=mi_uint3korr(header+1); + info->block_len=info->data_len+ (uint) header[4]; + info->filepos=filepos+5; + return return_val | BLOCK_LAST; + + case 11: + info->data_len=info->block_len=mi_uint2korr(header+1); + info->next_filepos=mi_sizekorr(header+3); + info->second_read=1; + info->filepos=filepos+11; + return return_val; + case 12: + info->data_len=info->block_len=mi_uint3korr(header+1); + info->next_filepos=mi_sizekorr(header+4); + info->second_read=1; + info->filepos=filepos+12; + return return_val; + } + +err: + my_errno=HA_ERR_WRONG_IN_RECORD; /* Garbage */ + return BLOCK_ERROR; +} |