diff options
Diffstat (limited to 'mysys/my_delete.c')
| -rw-r--r-- | mysys/my_delete.c | 166 |
1 files changed, 97 insertions, 69 deletions
diff --git a/mysys/my_delete.c b/mysys/my_delete.c index 0655501aa16..c1a821e90c2 100644 --- a/mysys/my_delete.c +++ b/mysys/my_delete.c @@ -17,13 +17,23 @@ #include "mysys_err.h" #include <my_sys.h> +#ifdef _WIN32 +static int my_win_unlink(const char *name); +#endif + int my_delete(const char *name, myf MyFlags) { int err; DBUG_ENTER("my_delete"); DBUG_PRINT("my",("name %s MyFlags %lu", name, MyFlags)); - if ((err = unlink(name)) == -1) +#ifdef _WIN32 + err = my_win_unlink(name); +#else + err = unlink(name); +#endif + + if(err) { my_errno=errno; if (MyFlags & (MY_FAE+MY_WME)) @@ -36,90 +46,108 @@ int my_delete(const char *name, myf MyFlags) DBUG_RETURN(err); } /* my_delete */ -#if defined(__WIN__) -/** - Delete file which is possibly not closed. - This function is intended to be used exclusively as a temporal solution - for Win NT in case when it is needed to delete a not closed file (note - that the file must be opened everywhere with FILE_SHARE_DELETE mode). - Deleting not-closed files can not be supported on Win 98|ME (and because - of that is considered harmful). - - The function deletes the file with its preliminary renaming. This is - because when not-closed share-delete file is deleted it still lives on - a disk until it will not be closed everwhere. This may conflict with an - attempt to create a new file with the same name. The deleted file is - renamed to <name>.<num>.deleted where <name> - the initial name of the - file, <num> - a hexadecimal number chosen to make the temporal name to - be unique. +#if defined (_WIN32) +/* + Delete file. - @param the name of the being deleted file - @param the flags instructing how to react on an error internally in - the function + The function also makes best effort to minimize number of errors, + where another program (or thread in the current program) has the the same file + open. - @note The per-thread @c my_errno holds additional info for a caller to - decide how critical the error can be. + We're using 2 tricks to prevent the errors. - @retval - 0 ok - @retval - 1 error + 1. A usual Win32's DeleteFile() can with ERROR_SHARED_VIOLATION, + because the file is opened in another application (often, antivirus or backup) + + We avoid the error by using CreateFile() with FILE_FLAG_DELETE_ON_CLOSE, instead + of DeleteFile() + 2. If file which is deleted (delete on close) but has not entirely gone, + because it is still opened by some app, an attempt to trcreate file with the + same name would result in yet another error. The workaround here is renaming + a file to unique name. -*/ -int nt_share_delete(const char *name, myf MyFlags) + Symbolic link are deleted without renaming. Directories are not deleted. + */ +static int my_win_unlink(const char *name) { - char buf[MAX_PATH + 20]; - ulong cnt; - DBUG_ENTER("nt_share_delete"); - DBUG_PRINT("my",("name %s MyFlags %d", name, MyFlags)); - - for (cnt= GetTickCount(); cnt; cnt--) + HANDLE handle= INVALID_HANDLE_VALUE; + DWORD attributes; + DWORD last_error; + char unique_filename[MAX_PATH + 35]; + unsigned long long tsc; /* time stamp counter, for unique filename*/ + + DBUG_ENTER("my_win_unlink"); + attributes= GetFileAttributes(name); + if (attributes == INVALID_FILE_ATTRIBUTES) { - errno= 0; - sprintf(buf, "%s.%08X.deleted", name, cnt); - if (MoveFile(name, buf)) - break; - - if ((errno= GetLastError()) == ERROR_ALREADY_EXISTS) - continue; - - /* This happened during tests with MERGE tables. */ - if (errno == ERROR_ACCESS_DENIED) - continue; - - DBUG_PRINT("warning", ("Failed to rename %s to %s, errno: %d", - name, buf, errno)); - break; + last_error= GetLastError(); + DBUG_PRINT("error",("GetFileAttributes(%s) failed with %u\n", name, last_error)); + goto error; } - if (errno == ERROR_FILE_NOT_FOUND) + if (attributes & FILE_ATTRIBUTE_DIRECTORY) { - my_errno= ENOENT; // marking, that `name' doesn't exist + DBUG_PRINT("error",("can't remove %s - it is a directory\n", name)); + errno= EINVAL; + DBUG_RETURN(-1); } - else if (errno == 0) + + if (attributes & FILE_ATTRIBUTE_REPARSE_POINT) + { + /* Symbolic link. Delete link, the not target */ + if (!DeleteFile(name)) + { + last_error= GetLastError(); + DBUG_PRINT("error",("DeleteFile(%s) failed with %u\n", name,last_error)); + goto error; + } + DBUG_RETURN(0); + } + + handle= CreateFile(name, DELETE, 0, NULL, OPEN_EXISTING, FILE_FLAG_DELETE_ON_CLOSE, NULL); + if (handle != INVALID_HANDLE_VALUE) { - if (DeleteFile(buf)) - DBUG_RETURN(0); /* - The below is more complicated than necessary. For some reason, the - assignment to my_errno clears the error number, which is retrieved - by GetLastError() (VC2005EE). Assigning to errno first, allows to - retrieve the correct value. + We opened file without sharing flags (exclusive), noone else has this file + opened, thus it is save to close handle to remove it. No renaming is + necessary. */ - errno= GetLastError(); - if (errno == 0) - my_errno= ENOENT; // marking, that `buf' doesn't exist - else - my_errno= errno; + CloseHandle(handle); + DBUG_RETURN(0); + } + + /* + Can't open file exclusively, hence the file must be already opened by + someone else. Open it for delete (with all FILE_SHARE flags set), + rename to unique name, close. + */ + handle= CreateFile(name, DELETE, FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE, + NULL, OPEN_EXISTING, FILE_FLAG_DELETE_ON_CLOSE, NULL); + if (handle == INVALID_HANDLE_VALUE) + { + last_error= GetLastError(); + DBUG_PRINT("error", + ("CreateFile(%s) with FILE_FLAG_DELETE_ON_CLOSE failed with %u\n", + name,last_error)); + goto error; } - else - my_errno= errno; - if (MyFlags & (MY_FAE+MY_WME)) - my_error(EE_DELETE, MYF(ME_BELL + ME_WAITTANG + (MyFlags & ME_NOINPUT)), - name, my_errno); + tsc= __rdtsc(); + my_snprintf(unique_filename,sizeof(unique_filename),"%s.%llx.deleted", + name, tsc); + if (!MoveFile(name, unique_filename)) + { + DBUG_PRINT("warning", ("moving %s to unique filename failed, error %u\n", + name,GetLastError())); + } + + CloseHandle(handle); + DBUG_RETURN(0); + +error: + my_osmaperr(last_error); DBUG_RETURN(-1); } -#endif +#endif
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