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/*
* Copy entire files.
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/bin/pg_combinebackup/copy_file.h
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#ifdef HAVE_COPYFILE_H
#include <copyfile.h>
#endif
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "common/file_perm.h"
#include "common/logging.h"
#include "copy_file.h"
static void copy_file_blocks(const char *src, const char *dst,
pg_checksum_context *checksum_ctx);
#ifdef WIN32
static void copy_file_copyfile(const char *src, const char *dst);
#endif
/*
* Copy a regular file, optionally computing a checksum, and emitting
* appropriate debug messages. But if we're in dry-run mode, then just emit
* the messages and don't copy anything.
*/
void
copy_file(const char *src, const char *dst,
pg_checksum_context *checksum_ctx, bool dry_run)
{
/*
* In dry-run mode, we don't actually copy anything, nor do we read any
* data from the source file, but we do verify that we can open it.
*/
if (dry_run)
{
int fd;
if ((fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
pg_fatal("could not open \"%s\": %m", src);
if (close(fd) < 0)
pg_fatal("could not close \"%s\": %m", src);
}
/*
* If we don't need to compute a checksum, then we can use any special
* operating system primitives that we know about to copy the file; this
* may be quicker than a naive block copy.
*/
if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
{
char *strategy_name = NULL;
void (*strategy_implementation) (const char *, const char *) = NULL;
#ifdef WIN32
strategy_name = "CopyFile";
strategy_implementation = copy_file_copyfile;
#endif
if (strategy_name != NULL)
{
if (dry_run)
pg_log_debug("would copy \"%s\" to \"%s\" using strategy %s",
src, dst, strategy_name);
else
{
pg_log_debug("copying \"%s\" to \"%s\" using strategy %s",
src, dst, strategy_name);
(*strategy_implementation) (src, dst);
}
return;
}
}
/*
* Fall back to the simple approach of reading and writing all the blocks,
* feeding them into the checksum context as we go.
*/
if (dry_run)
{
if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
pg_log_debug("would copy \"%s\" to \"%s\"",
src, dst);
else
pg_log_debug("would copy \"%s\" to \"%s\" and checksum with %s",
src, dst, pg_checksum_type_name(checksum_ctx->type));
}
else
{
if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
pg_log_debug("copying \"%s\" to \"%s\"",
src, dst);
else
pg_log_debug("copying \"%s\" to \"%s\" and checksumming with %s",
src, dst, pg_checksum_type_name(checksum_ctx->type));
copy_file_blocks(src, dst, checksum_ctx);
}
}
/*
* Copy a file block by block, and optionally compute a checksum as we go.
*/
static void
copy_file_blocks(const char *src, const char *dst,
pg_checksum_context *checksum_ctx)
{
int src_fd;
int dest_fd;
uint8 *buffer;
const int buffer_size = 50 * BLCKSZ;
ssize_t rb;
unsigned offset = 0;
if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
pg_fatal("could not open file \"%s\": %m", src);
if ((dest_fd = open(dst, O_WRONLY | O_CREAT | O_EXCL | PG_BINARY,
pg_file_create_mode)) < 0)
pg_fatal("could not open file \"%s\": %m", dst);
buffer = pg_malloc(buffer_size);
while ((rb = read(src_fd, buffer, buffer_size)) > 0)
{
ssize_t wb;
if ((wb = write(dest_fd, buffer, rb)) != rb)
{
if (wb < 0)
pg_fatal("could not write file \"%s\": %m", dst);
else
pg_fatal("could not write file \"%s\": wrote only %d of %d bytes at offset %u",
dst, (int) wb, (int) rb, offset);
}
if (pg_checksum_update(checksum_ctx, buffer, rb) < 0)
pg_fatal("could not update checksum of file \"%s\"", dst);
offset += rb;
}
if (rb < 0)
pg_fatal("could not read file \"%s\": %m", dst);
pg_free(buffer);
close(src_fd);
close(dest_fd);
}
#ifdef WIN32
static void
copy_file_copyfile(const char *src, const char *dst)
{
if (CopyFile(src, dst, true) == 0)
{
_dosmaperr(GetLastError());
pg_fatal("could not copy \"%s\" to \"%s\": %m", src, dst);
}
}
#endif /* WIN32 */
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