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/*-
* Copyright (c) 2014-present MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __wt_filename --
* Build a file name in a scratch buffer, automatically calculate the length of the file name.
*/
int
__wt_filename(WT_SESSION_IMPL *session, const char *name, char **path)
{
return (__wt_nfilename(session, name, strlen(name), path));
}
/*
* __wt_nfilename --
* Build a file name in a scratch buffer. If the name is already an absolute path duplicate it,
* otherwise generate a path relative to the connection home directory.
*/
int
__wt_nfilename(WT_SESSION_IMPL *session, const char *name, size_t namelen, char **path)
{
WT_DECL_RET;
size_t len;
char *buf;
*path = NULL;
/*
* Needs to work with a NULL session handle - since this is called via the exists API which is
* used by the test utilities.
*/
if (session == NULL || __wt_absolute_path(name))
return (__wt_strndup(session, name, namelen, path));
len = strlen(S2C(session)->home) + 1 + namelen + 1;
WT_RET(__wt_calloc(session, 1, len, &buf));
WT_ERR(__wt_snprintf(
buf, len, "%s%s%.*s", S2C(session)->home, __wt_path_separator(), (int)namelen, name));
*path = buf;
return (0);
err:
__wt_free(session, buf);
return (ret);
}
/*
* __wt_filename_construct --
* Given unique identifiers, return a WT_ITEM of a generated file name of the given prefix type.
* Any identifier that is 0 will be skipped.
*/
int
__wt_filename_construct(WT_SESSION_IMPL *session, const char *path, const char *file_prefix,
uintmax_t id_1, uint32_t id_2, WT_ITEM *buf)
{
if (path != NULL && path[0] != '\0')
WT_RET(__wt_buf_catfmt(session, buf, "%s%s", path, __wt_path_separator()));
WT_RET(__wt_buf_catfmt(session, buf, "%s", file_prefix));
if (id_1 != UINTMAX_MAX)
WT_RET(__wt_buf_catfmt(session, buf, ".%010" PRIuMAX, id_1));
if (id_2 != UINT32_MAX)
WT_RET(__wt_buf_catfmt(session, buf, ".%010" PRIu32, id_2));
return (0);
}
/*
* __wt_remove_if_exists --
* Remove a file if it exists.
*/
int
__wt_remove_if_exists(WT_SESSION_IMPL *session, const char *name, bool durable)
{
bool exist;
WT_RET(__wt_fs_exist(session, name, &exist));
if (exist)
WT_RET(__wt_fs_remove(session, name, durable));
return (0);
}
/*
* __wt_copy_and_sync --
* Copy a file safely.
*/
int
__wt_copy_and_sync(WT_SESSION *wt_session, const char *from, const char *to)
WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
{
WT_DECL_ITEM(tmp);
WT_DECL_RET;
WT_FH *ffh, *tfh;
WT_SESSION_IMPL *session;
wt_off_t n, offset, size;
char *buf;
session = (WT_SESSION_IMPL *)wt_session;
ffh = tfh = NULL;
buf = NULL;
/*
* Remove the target file if it exists, then create a temporary file, copy the original into it
* and rename it into place. I don't think its necessary to remove the file, or create a copy
* and do a rename, it's likely safe to overwrite the backup file directly. I'm doing the remove
* and rename to insulate us from errors in other programs that might not detect a corrupted
* backup file; it's cheap insurance in a path where undetected failure is very bad.
*/
WT_ERR(__wt_scr_alloc(session, 0, &tmp));
WT_ERR(__wt_buf_fmt(session, tmp, "%s.copy", to));
WT_ERR(__wt_remove_if_exists(session, to, false));
WT_ERR(__wt_remove_if_exists(session, tmp->data, false));
/* Open the from and temporary file handles. */
WT_ERR(__wt_open(session, from, WT_FS_OPEN_FILE_TYPE_REGULAR, 0, &ffh));
WT_ERR(__wt_open(session, tmp->data, WT_FS_OPEN_FILE_TYPE_REGULAR,
WT_FS_OPEN_CREATE | WT_FS_OPEN_EXCLUSIVE, &tfh));
/*
* Allocate a copy buffer. Don't use a scratch buffer, this thing is big, and we don't want it
* hanging around.
*/
#define WT_BACKUP_COPY_SIZE (128 * 1024)
WT_ERR(__wt_malloc(session, WT_BACKUP_COPY_SIZE, &buf));
/* Get the file's size, then copy the bytes. */
WT_ERR(__wt_filesize(session, ffh, &size));
for (offset = 0; size > 0; size -= n, offset += n) {
n = WT_MIN(size, WT_BACKUP_COPY_SIZE);
WT_ERR(__wt_read(session, ffh, offset, (size_t)n, buf));
WT_ERR(__wt_write(session, tfh, offset, (size_t)n, buf));
}
/* Close the from handle, then swap the temporary file into place. */
WT_ERR(__wt_close(session, &ffh));
WT_ERR(__wt_fsync(session, tfh, true));
WT_ERR(__wt_close(session, &tfh));
ret = __wt_fs_rename(session, tmp->data, to, true);
err:
WT_TRET(__wt_close(session, &ffh));
WT_TRET(__wt_close(session, &tfh));
__wt_free(session, buf);
__wt_scr_free(session, &tmp);
return (ret);
}
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