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file.c
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file.c
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/*-------------------------------------------------------------------------
*
* file.c:
*
* Copyright (c) 2009-2011, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
*
*-------------------------------------------------------------------------
*/
#include "pg_rman.h"
#include "storage/block.h"
#include "storage/bufpage.h"
#ifdef HAVE_LIBZ
#include <zlib.h>
#endif
/* ----------------------------------------------------------------
* Reader and Writer
* ----------------------------------------------------------------
*/
typedef struct Reader Reader;
typedef size_t (*ReaderClose)(Reader *self);
typedef size_t (*ReaderRead)(Reader *self, void *buf, size_t len);
struct Reader
{
ReaderClose close; /* close and returns physical read size */
ReaderRead read;
};
typedef struct Writer Writer;
typedef size_t (*WriterClose)(Writer *self, pg_crc32 *crc);
typedef void (*WriterWrite)(Writer *self, const void *buf, size_t len);
struct Writer
{
WriterClose close; /* close and returns physical written size */
WriterWrite write;
};
static Reader *FileReader(const char *path);
static Writer *FileWriter(const char *path);
static Reader *ZlibReader(Reader *inner);
static Writer *ZlibWriter(Writer *inner);
static Reader *DataReader(Reader *inner);
static Reader *BackupReader(Reader *inner);
#define inner_read(self, buf, len) \
((self)->inner->read((self)->inner, (buf), (len)))
#define inner_write(self, buf, len) \
((self)->inner->write((self)->inner, (buf), (len)))
/* ----------------------------------------------------------------
* PostgreSQL data files
* ----------------------------------------------------------------
*/
#define PG_PAGE_LAYOUT_VERSION_v81 3 /* 8.1 - 8.2 */
#define PG_PAGE_LAYOUT_VERSION_v83 4 /* 8.3 - */
/* 80000 <= PG_VERSION_NUM < 80300 */
typedef struct PageHeaderData_v80
{
XLogRecPtr pd_lsn;
TimeLineID pd_tli;
LocationIndex pd_lower;
LocationIndex pd_upper;
LocationIndex pd_special;
uint16 pd_pagesize_version;
ItemIdData pd_linp[1];
} PageHeaderData_v80;
#define PageGetPageSize_v80(page) \
((Size) ((page)->pd_pagesize_version & (uint16) 0xFF00))
#define PageGetPageLayoutVersion_v80(page) \
((page)->pd_pagesize_version & 0x00FF)
#define SizeOfPageHeaderData_v80 (offsetof(PageHeaderData_v80, pd_linp))
/* 80300 <= PG_VERSION_NUM */
typedef struct PageHeaderData_v83
{
XLogRecPtr pd_lsn;
uint16 pd_tli;
uint16 pd_flags;
LocationIndex pd_lower;
LocationIndex pd_upper;
LocationIndex pd_special;
uint16 pd_pagesize_version;
TransactionId pd_prune_xid;
ItemIdData pd_linp[1];
} PageHeaderData_v83;
#define PageGetPageSize_v83(page) \
((Size) ((page)->pd_pagesize_version & (uint16) 0xFF00))
#define PageGetPageLayoutVersion_v83(page) \
((page)->pd_pagesize_version & 0x00FF)
#define SizeOfPageHeaderData_v83 (offsetof(PageHeaderData_v83, pd_linp))
#define PD_VALID_FLAG_BITS_v83 0x0007
typedef union DataPage
{
XLogRecPtr pd_lsn;
PageHeaderData_v80 v80; /* 8.0 - 8.2 */
PageHeaderData_v83 v83; /* 8.3 - */
char data[1];
} DataPage;
static void do_copy(pgFile *file, Reader *in, Writer *out);
/*
* Backup a file.
*/
void
pgFile_backup(pgFile *file, const char *from, const char *to)
{
Reader *in;
Writer *out;
char path[MAXPGPATH];
Assert(file);
Assert(from);
Assert(to);
/* Reader */
join_path_components(path, from, file->name);
if ((in = FileReader(path)) == NULL)
{
file->mode = MISSING_FILE;
return; /* have been deleted, ignore this file */
}
if (file->flags & PGFILE_DATA)
in = DataReader(in);
/* Writer */
join_path_components(path, to, file->name);
out = FileWriter(path);
if (file->flags & PGFILE_ZLIB)
out = ZlibWriter(out);
do_copy(file, in, out);
elog(LOG, "backup file: %s (%.2f%% of %lu bytes)",
file->name, 100.0 * file->written_size / file->size,
(unsigned long) file->size);
}
/*
* Restore a file.
*/
void
pgFile_restore(pgFile *file, const char *from, const char *to)
{
Reader *in;
Writer *out;
char path[MAXPGPATH];
Assert(file);
Assert(from);
Assert(to);
/* Reader */
join_path_components(path, from, file->name);
if ((in = FileReader(path)) == NULL)
return; /* have been deleted, ignore this file */
if (file->flags & PGFILE_ZLIB)
in = ZlibReader(in);
if (file->flags & PGFILE_DATA)
in = BackupReader(in);
/* Writer */
join_path_components(path, to, file->name);
out = FileWriter(path);
do_copy(file, in, out);
/* update file permission */
if (chmod(path, file->mode) != 0)
ereport(ERROR,
(errcode_errno(),
errmsg("could not change mode of \"%s\": ", path)));
elog(LOG, "restore file: %s (%.2f%% of %lu bytes)",
file->name, 100.0 * file->written_size / file->size,
(unsigned long) file->size);
/* TODO: restore other attributes, including mtime. */
}
static void
do_copy(pgFile *file, Reader *in, Writer *out)
{
void *buffer;
size_t buflen;
size_t len;
pg_crc32 crc;
Assert(block_size > 0);
Assert(wal_block_size > 0);
buflen = Max(block_size, wal_block_size);
buffer = pgut_malloc(buflen); /* use malloc for memroy alignment */
/* copy contents */
while ((len = in->read(in, buffer, buflen)) > 0)
{
CHECK_FOR_INTERRUPTS();
out->write(out, buffer, len);
}
/* close in and out */
file->read_size = in->close(in);
file->written_size = out->close(out, &crc);
file->crc = crc;
file->flags |= PGFILE_CRC;
free(buffer);
}
/* ----------------------------------------------------------------
* File Reader
* ----------------------------------------------------------------
*/
typedef struct FReader
{
Reader base;
FILE *fp;
size_t done;
} FReader;
static size_t FReader_close(FReader *self);
static size_t FReader_read(FReader *self, void *buf, size_t len);
/* returns NULL if file not found */
static Reader *
FileReader(const char *path)
{
FReader *self;
FILE *fp;
if ((fp = pgut_fopen(path, "R")) == NULL)
return NULL;
self = pgut_new(FReader);
self->base.close = (ReaderClose) FReader_close;
self->base.read = (ReaderRead) FReader_read;
self->fp = fp;
self->done = 0;
return (Reader *) self;
}
static size_t
FReader_close(FReader *self)
{
size_t done = self->done;
fclose(self->fp);
free(self);
return done;
}
static size_t
FReader_read(FReader *self, void *buf, size_t len)
{
errno = 0;
len = fread(buf, 1, len, self->fp);
if (errno != 0)
ereport(ERROR,
(errcode_errno(),
errmsg("could not read file: ")));
self->done += len;
return len;
}
/* ----------------------------------------------------------------
* File Writer
* ----------------------------------------------------------------
*/
typedef struct FWriter
{
Writer base;
FILE *fp;
size_t done;
pg_crc32 crc;
} FWriter;
static size_t FWriter_close(FWriter *self, pg_crc32 *crc);
static void FWriter_write(FWriter *self, const void *buf, size_t len);
static Writer *
FileWriter(const char *path)
{
FWriter *self;
FILE *fp;
fp = pgut_fopen(path, "w");
self = pgut_new(FWriter);
self->base.close = (WriterClose) FWriter_close;
self->base.write = (WriterWrite) FWriter_write;
self->fp = fp;
self->done = 0;
INIT_CRC32(self->crc);
return (Writer *) self;
}
static size_t
FWriter_close(FWriter *self, pg_crc32 *crc)
{
size_t done = self->done;
if (crc)
{
FIN_CRC32(self->crc);
*crc = self->crc;
}
fclose(self->fp);
free(self);
return done;
}
static void
FWriter_write(FWriter *self, const void *buf, size_t len)
{
if (fwrite(buf, 1, len, self->fp) != len)
ereport(ERROR,
(errcode_errno(),
errmsg("could not write file: ")));
self->done += len;
COMP_CRC32(self->crc, buf, len);
}
#ifdef HAVE_LIBZ
#define Z_BUFSIZE (64 * 1024) /* 64KB */
/* ----------------------------------------------------------------
* LibZ Reader
* ----------------------------------------------------------------
*/
typedef struct ZReader
{
Reader base;
Reader *inner;
z_stream z;
Byte buf[Z_BUFSIZE];
} ZReader;
static size_t ZReader_close(ZReader *self);
static size_t ZReader_read(ZReader *self, void *buf, size_t len);
static Reader *
ZlibReader(Reader *inner)
{
ZReader *self = pgut_new(ZReader);
memset(self, 0, sizeof(ZReader));
self->base.close = (ReaderClose) ZReader_close;
self->base.read = (ReaderRead) ZReader_read;
self->inner = inner;
if (inflateInit(&self->z) != Z_OK)
elog(ERROR, "could not create z_stream: %s", self->z.msg);
return (Reader *) self;
}
static size_t
ZReader_close(ZReader *self)
{
size_t done;
if (inflateEnd(&self->z) != Z_OK)
elog(ERROR, "could not close z_stream: %s", self->z.msg);
done = self->inner->close(self->inner);
free(self);
return done;
}
static size_t
ZReader_read(ZReader *self, void *buf, size_t len)
{
self->z.next_out = buf;
self->z.avail_out = len;
while (self->z.avail_out > 0)
{
/* fill input buffer if empty */
if (self->z.avail_in == 0)
{
size_t sz = inner_read(self, self->buf, Z_BUFSIZE);
if (sz == 0)
break;
self->z.next_in = self->buf;
self->z.avail_in = sz;
}
/* inflate into output buffer */
switch (inflate(&self->z, Z_NO_FLUSH))
{
case Z_STREAM_END:
case Z_OK:
continue; /* ok, go next */
default:
elog(ERROR, "could not inflate z_stream: %s", self->z.msg);
}
}
return len - self->z.avail_out;
}
/* ----------------------------------------------------------------
* LibZ Writer
* ----------------------------------------------------------------
*/
typedef struct ZWriter
{
Writer base;
Writer *inner;
z_stream z;
Byte buf[Z_BUFSIZE];
} ZWriter;
static size_t ZWriter_close(ZWriter *self, pg_crc32 *crc);
static void ZWriter_write(ZWriter *self, const void *buf, size_t len);
static Writer *
ZlibWriter(Writer *inner)
{
ZWriter *self = pgut_new(ZWriter);
memset(self, 0, sizeof(ZWriter));
self->base.close = (WriterClose) ZWriter_close;
self->base.write = (WriterWrite) ZWriter_write;
self->inner = inner;
if (deflateInit(&self->z, Z_DEFAULT_COMPRESSION) != Z_OK)
elog(ERROR, "could not create z_stream: %s", self->z.msg);
self->z.next_out = self->buf;
self->z.avail_out = Z_BUFSIZE;
return (Writer *) self;
}
static size_t
ZWriter_close(ZWriter *self, pg_crc32 *crc)
{
size_t done;
/* finish zstream */
self->z.next_in = NULL;
self->z.avail_in = 0;
if (deflate(&self->z, Z_FINISH) < 0)
elog(ERROR, "could not finish z_stream: %s", self->z.msg);
inner_write(self, self->buf, Z_BUFSIZE - self->z.avail_out);
if (deflateEnd(&self->z) != Z_OK)
elog(ERROR, "could not close z_stream: %s", self->z.msg);
done = self->inner->close(self->inner, crc);
free(self);
return done;
}
static void
ZWriter_write(ZWriter *self, const void *buf, size_t len)
{
self->z.next_in = (void *) buf;
self->z.avail_in = len;
/* compresses until an input buffer becomes empty. */
while (self->z.avail_in > 0)
{
if (deflate(&self->z, Z_NO_FLUSH) < 0)
elog(ERROR, "could not deflate z_stream: %s", self->z.msg);
if (self->z.avail_out == 0)
{
inner_write(self, self->buf, Z_BUFSIZE);
self->z.next_out = self->buf;
self->z.avail_out = Z_BUFSIZE;
}
}
}
#else /* HAVE_LIBZ */
static Reader *
ZlibReader(Reader *inner)
{
elog(ERROR, "zlib is unavailable");
}
static Writer *
ZlibWriter(Writer *inner)
{
elog(ERROR, "zlib is unavailable");
}
#endif /* HAVE_LIBZ */
/* ----------------------------------------------------------------
* Reader for backup and restore data files
* ----------------------------------------------------------------
*/
typedef struct DReader
{
Reader base;
Reader *inner;
} DReader;
static size_t DReader_close(DReader *self);
static size_t Data_read(DReader *self, char *buf, size_t len);
static size_t Backup_read(DReader *self, DataPage *buf, size_t len);
static bool parse_header(const DataPage *page, uint16 *lower, uint16 *upper);
/*
* DataReader - Data file compresser.
*
* Unused free space is removed. If lsn is not NULL, only modified pages
* after the lsn will be copied.
*/
static Reader *
DataReader(Reader *inner)
{
DReader *self = pgut_new(DReader);
self->base.close = (ReaderClose) DReader_close;
self->base.read = (ReaderRead) Data_read;
self->inner = inner;
return (Reader *) self;
}
/*
* BackupReader - Data file decompresser.
*/
static Reader *
BackupReader(Reader *inner)
{
DReader *self = pgut_new(DReader);
self->base.close = (ReaderClose) DReader_close;
self->base.read = (ReaderRead) Backup_read;
self->inner = inner;
return (Reader *) self;
}
static size_t
DReader_close(DReader *self)
{
size_t done;
done = self->inner->close(self->inner);
free(self);
return done;
}
static size_t
Data_read(DReader *self, char *buf, size_t len)
{
DataPage page;
size_t done;
uint16 pd_lower;
uint16 pd_upper;
int upper_length;
/* read a page at once */
done = 0;
while (done < block_size)
{
size_t sz = inner_read(self, page.data + done, block_size - done);
if (sz == 0)
break;
done += sz;
}
if (done == 0)
return 0; /* eof */
if (done != block_size || !parse_header(&page, &pd_lower, &pd_upper))
goto bad_file;
/* XXX: repair fragmentation with PageRepairFragmentation? */
#if 0
/* if the page has not been modified since last backup, skip it */
if (lsn && !XLogRecPtrIsInvalid(page.pd_lsn) && XLByteLT(page.pd_lsn, *lsn))
goto retry;
#endif
upper_length = block_size - pd_upper;
if (len > pd_lower + upper_length)
elog(ERROR, "buffer too small");
/* remove hole of the page */
memcpy(buf, page.data, pd_lower);
memcpy(buf + pd_lower, page.data + pd_upper, upper_length);
return pd_lower + upper_length;
bad_file:
/* TODO: If a invalid data page was found, fallback to simple copy. */
elog(ERROR, "not a data file");
return 0;
}
static size_t
Backup_read(DReader *self, DataPage *buf, size_t len)
{
size_t sz;
uint16 pd_lower;
uint16 pd_upper;
int lower_remain;
int upper_length;
int header_size;
Assert(len >= block_size);
if (server_version < 80300)
header_size = SizeOfPageHeaderData_v80;
else
header_size = SizeOfPageHeaderData_v83;
/* read each page and write the page excluding hole */
if ((sz = inner_read(self, buf, header_size)) == 0)
return 0;
if (sz != header_size ||
!parse_header(buf, &pd_lower, &pd_upper))
goto bad_file;
lower_remain = pd_lower - header_size;
upper_length = block_size - pd_upper;
/* read remain lower and upper, and fill the hole with zero. */
if (inner_read(self, buf + header_size, lower_remain) != lower_remain ||
inner_read(self, buf + pd_upper, upper_length) != upper_length)
goto bad_file;
memset(buf + pd_lower, 0, pd_upper - pd_lower);
return block_size;
bad_file:
elog(ERROR, "not a data file");
return 0;
}
static bool
parse_header(const DataPage *page, uint16 *lower, uint16 *upper)
{
uint16 page_layout_version;
/* Determine page layout version */
if (server_version < 80300)
page_layout_version = PG_PAGE_LAYOUT_VERSION_v81;
else
page_layout_version = PG_PAGE_LAYOUT_VERSION_v83;
/* Check normal case */
if (server_version < 80300)
{
const PageHeaderData_v80 *v80 = &page->v80;
if (PageGetPageSize_v80(v80) == block_size &&
PageGetPageLayoutVersion_v80(v80) == page_layout_version &&
v80->pd_lower >= SizeOfPageHeaderData_v80 &&
v80->pd_lower <= v80->pd_upper &&
v80->pd_upper <= v80->pd_special &&
v80->pd_special <= block_size &&
v80->pd_special == MAXALIGN(v80->pd_special) &&
!XLogRecPtrIsInvalid(v80->pd_lsn))
{
*lower = v80->pd_lower;
*upper = v80->pd_upper;
return true;
}
}
else
{
const PageHeaderData_v83 *v83 = &page->v83;
if (PageGetPageSize_v83(v83) == block_size &&
PageGetPageLayoutVersion_v83(v83) == page_layout_version &&
(v83->pd_flags & ~PD_VALID_FLAG_BITS_v83) == 0 &&
v83->pd_lower >= SizeOfPageHeaderData_v83 &&
v83->pd_lower <= v83->pd_upper &&
v83->pd_upper <= v83->pd_special &&
v83->pd_special <= block_size &&
v83->pd_special == MAXALIGN(v83->pd_special) &&
!XLogRecPtrIsInvalid(v83->pd_lsn))
{
*lower = v83->pd_lower;
*upper = v83->pd_upper;
return true;
}
}
*lower = *upper = 0;
return false;
}