109 lines
3.0 KiB
C
109 lines
3.0 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1997,2008 Oracle. All rights reserved.
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*
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* $Id: os_unlink.c 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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#include "db_config.h"
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#include "db_int.h"
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/*
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* __os_unlink --
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* Remove a file.
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*/
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int
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__os_unlink(env, path, overwrite_test)
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ENV *env;
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const char *path;
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int overwrite_test;
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{
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DB_ENV *dbenv;
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HANDLE h;
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_TCHAR *tpath, *orig_tpath, buf[DB_MAXPATHLEN];
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u_int32_t id;
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int ret, t_ret;
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dbenv = env == NULL ? NULL : env->dbenv;
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if (dbenv != NULL &&
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FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS | DB_VERB_FILEOPS_ALL))
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__db_msg(env, "fileops: unlink %s", path);
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/* Optionally overwrite the contents of the file to enhance security. */
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if (dbenv != NULL && overwrite_test && F_ISSET(dbenv, DB_ENV_OVERWRITE))
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(void)__db_file_multi_write(env, path);
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TO_TSTRING(env, path, tpath, ret);
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if (ret != 0)
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return (ret);
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orig_tpath = tpath;
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LAST_PANIC_CHECK_BEFORE_IO(env);
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/*
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* Windows NT and its descendants allow removal of open files, but the
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* DeleteFile Win32 system call isn't equivalent to a POSIX unlink.
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* Firstly, it only succeeds if FILE_SHARE_DELETE is set when the file
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* is opened. Secondly, it leaves the file in a "zombie" state, where
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* it can't be opened again, but a new file with the same name can't be
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* created either.
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*
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* Since we depend on being able to recreate files (during recovery,
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* say), we have to first rename the file, and then delete it. It
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* still hangs around, but with a name we don't care about. The rename
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* will fail if the file doesn't exist, which isn't a problem, but if
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* it fails for some other reason, we need to know about it or a
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* subsequent open may fail for no apparent reason.
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*/
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if (__os_is_winnt()) {
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__os_unique_id(env, &id);
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_sntprintf(buf, DB_MAXPATHLEN, _T("%s.del.%010u"), tpath, id);
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if (MoveFile(tpath, buf))
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tpath = buf;
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else {
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ret = __os_get_syserr();
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if (__os_posix_err(ret) != ENOENT)
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__db_err(env, ret,
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"MoveFile: rename %s to temporary file",
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path);
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}
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/*
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* Try removing the file using the delete-on-close flag. This
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* plays nicer with files that are still open than DeleteFile.
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*/
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h = CreateFile(tpath, 0,
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FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
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NULL, OPEN_EXISTING, FILE_FLAG_DELETE_ON_CLOSE, 0);
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if (h != INVALID_HANDLE_VALUE) {
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(void)CloseHandle (h);
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if (GetFileAttributes(tpath) == INVALID_FILE_ATTRIBUTES)
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goto skipdel;
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}
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}
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RETRY_CHK((!DeleteFile(tpath)), ret);
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skipdel:
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FREE_STRING(env, orig_tpath);
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/*
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* XXX
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* We shouldn't be testing for an errno of ENOENT here, but ENOENT
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* signals that a file is missing, and we attempt to unlink things
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* (such as v. 2.x environment regions, in ENV->remove) that we
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* are expecting not to be there. Reporting errors in these cases
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* is annoying.
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*/
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if (ret != 0) {
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if ((t_ret = __os_posix_err(ret)) != ENOENT)
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__db_syserr(env, ret, "DeleteFile: %s", path);
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ret = t_ret;
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}
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return (ret);
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}
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