win_efile.c

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/* ``The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved via the world wide web at http://www.erlang.org/.
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Initial Developer of the Original Code is Ericsson Utvecklings AB.
 * Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
 * AB. All Rights Reserved.''
 * 
 *     $Id$
 */
/*
 * Purpose: Provides file and directory operations for Windows.
 */

#include <windows.h>
#include "sys.h"
#include <ctype.h>

#include "erl_efile.h"

/*
 * Microsoft-specific function to map a WIN32 error code to a Posix errno.
 */

#define ISSLASH(a)  ((a) == '\\' || (a) == '/')

#define ISDIR(st) (((st).st_mode&S_IFMT) == S_IFDIR)
#define ISREG(st) (((st).st_mode&S_IFMT) == S_IFREG)

#define IS_DOT_OR_DOTDOT(s) \
    (s[0] == '.' && (s[1] == '\0' || (s[1] == '.' && s[2] == '\0')))

#ifndef INVALID_FILE_ATTRIBUTES
#define INVALID_FILE_ATTRIBUTES ((DWORD) 0xFFFFFFFF)
#endif

static int check_error(int result, Efile_error* errInfo);
static int set_error(Efile_error* errInfo);
static int IsRootUNCName(const char* path);
static int extract_root(char* name);
static unsigned short dos_to_posix_mode(int attr, const char *name);

static int errno_map(DWORD last_error) {

    switch (last_error) {
    case ERROR_SUCCESS:
	return 0;
    case ERROR_INVALID_FUNCTION:
    case ERROR_INVALID_DATA:
    case ERROR_INVALID_PARAMETER:
    case ERROR_INVALID_TARGET_HANDLE:
    case ERROR_INVALID_CATEGORY:
    case ERROR_NEGATIVE_SEEK:
	return EINVAL;
    case ERROR_DIR_NOT_EMPTY:
	return EEXIST;
    case ERROR_BAD_FORMAT:
	return ENOEXEC;
    case ERROR_PATH_NOT_FOUND:
    case ERROR_FILE_NOT_FOUND:
    case ERROR_NO_MORE_FILES:
	return ENOENT;
    case ERROR_TOO_MANY_OPEN_FILES:
	return EMFILE;
    case ERROR_ACCESS_DENIED:
    case ERROR_INVALID_ACCESS:
    case ERROR_CURRENT_DIRECTORY:
    case ERROR_SHARING_VIOLATION:
    case ERROR_LOCK_VIOLATION:
    case ERROR_INVALID_PASSWORD:
    case ERROR_DRIVE_LOCKED:
	return EACCES;
    case ERROR_INVALID_HANDLE:
	return EBADF;
    case ERROR_NOT_ENOUGH_MEMORY:
    case ERROR_OUTOFMEMORY:
    case ERROR_OUT_OF_STRUCTURES:
	return ENOMEM;
    case ERROR_INVALID_DRIVE:
    case ERROR_BAD_UNIT:
    case ERROR_NOT_READY:
    case ERROR_REM_NOT_LIST:
    case ERROR_DUP_NAME:
    case ERROR_BAD_NETPATH:
    case ERROR_NETWORK_BUSY:
    case ERROR_DEV_NOT_EXIST:
    case ERROR_BAD_NET_NAME:
	return ENXIO;
    case ERROR_NOT_SAME_DEVICE:
	return EXDEV;
    case ERROR_WRITE_PROTECT:
	return EROFS;
    case ERROR_BAD_LENGTH:
    case ERROR_BUFFER_OVERFLOW:
	return E2BIG;
    case ERROR_SEEK:
    case ERROR_SECTOR_NOT_FOUND:
	return ESPIPE;
    case ERROR_NOT_DOS_DISK:
	return ENODEV;
    case ERROR_GEN_FAILURE:
	return ENODEV;
    case ERROR_SHARING_BUFFER_EXCEEDED:
    case ERROR_NO_MORE_SEARCH_HANDLES:
	return EMFILE;
    case ERROR_HANDLE_EOF:
    case ERROR_BROKEN_PIPE:
	return EPIPE;
    case ERROR_HANDLE_DISK_FULL:
    case ERROR_DISK_FULL:
	return ENOSPC;
    case ERROR_NOT_SUPPORTED:
	return ENOTSUP;
    case ERROR_FILE_EXISTS:
    case ERROR_ALREADY_EXISTS:
    case ERROR_CANNOT_MAKE:
	return EEXIST;
    case ERROR_ALREADY_ASSIGNED:
	return EBUSY;
    case ERROR_NO_PROC_SLOTS:
	return EAGAIN;
    case ERROR_ARENA_TRASHED:
    case ERROR_INVALID_BLOCK:
    case ERROR_BAD_ENVIRONMENT:
    case ERROR_BAD_COMMAND:
    case ERROR_CRC:
    case ERROR_OUT_OF_PAPER:
    case ERROR_READ_FAULT:
    case ERROR_WRITE_FAULT:
    case ERROR_WRONG_DISK:
    case ERROR_NET_WRITE_FAULT:
	return EIO;
    default: /* not to do with files I expect. */
	return EIO;
    }	
}

static int
check_error(int result, Efile_error* errInfo)
{
    if (result < 0) {
	errInfo->posix_errno = errno;
	errInfo->os_errno = GetLastError();
	return 0;
    }
    return 1;
}

/*
 * Fills the provided error information structure with information
 * with the error code given by GetLastError() and its corresponding
 * Posix error number.
 *
 * Returns 0.
 */

static int
set_error(Efile_error* errInfo)
{
    errInfo->posix_errno = errno_map(errInfo->os_errno = GetLastError());
    return 0;
}

/*
 * A writev with Unix semantics, but with Windows arguments 
 */
static int 
win_writev(Efile_error* errInfo,
	   HANDLE fd,                  /* handle to file */
	   FILE_SEGMENT_ELEMENT iov[], /* array of buffer pointers */
	   DWORD *size)                /* number of bytes to write */
{
    OVERLAPPED ov;
    ov.Offset = 0L;
    ov.OffsetHigh = 0L;
    ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (ov.hEvent == NULL)
	return set_error(errInfo);
    if (! write_file_gather(fd, iov, *size, NULL, &ov))
	return set_error(errInfo);
    if (WaitForSingleObject(ov.hEvent, INFINITE) != WAIT_OBJECT_0)
	return set_error(errInfo);
    if (! GetOverlappedResult(fd, &ov, size, FALSE))
	return set_error(errInfo);
    return 1;
}



int
efile_mkdir(errInfo, name)
Efile_error* errInfo;		/* Where to return error codes. */
char* name;			/* Name of directory to create. */
{
    return check_error(mkdir(name), errInfo);
}

int
efile_rmdir(errInfo, name)
Efile_error* errInfo;		/* Where to return error codes. */
char* name;			/* Name of directory to delete. */
{
    OSVERSIONINFO os;
    DWORD attr;

    if (RemoveDirectory(name) != FALSE) {
	return 1;
    }
    errno = errno_map(GetLastError());
    if (errno == EACCES) {
	attr = GetFileAttributes(name);
	if (attr != (DWORD) -1) {
	    if ((attr & FILE_ATTRIBUTE_DIRECTORY) == 0) {
		/* 
		 * Windows 95 reports calling RemoveDirectory on a file as an 
		 * EACCES, not an ENOTDIR.
		 */
		
		errno = ENOTDIR;
		goto end;
	    }

	    /* 
	     * Windows 95 reports removing a non-empty directory as
	     * an EACCES, not an EEXIST.  If the directory is not empty,
	     * change errno so caller knows what's going on.
	     */

	    os.dwOSVersionInfoSize = sizeof(os);
	    GetVersionEx(&os);
	    if (os.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS) {
		HANDLE handle;
		WIN32_FIND_DATA data;
		char buffer[2*MAX_PATH];
		int len;

		len = strlen(name);
		strcpy(buffer, name);
		if (buffer[0] && buffer[len-1] != '\\' && buffer[len-1] != '/') {
		    strcat(buffer, "\\");
		}
		strcat(buffer, "*.*");
		handle = FindFirstFile(buffer, &data);
		if (handle != INVALID_HANDLE_VALUE) {
		    while (1) {
			if ((strcmp(data.cFileName, ".") != 0)
				&& (strcmp(data.cFileName, "..") != 0)) {
			    /*
			     * Found something in this directory.
			     */

			    errno = EEXIST;
			    break;
			}
			if (FindNextFile(handle, &data) == FALSE) {
			    break;
			}
		    }
		    FindClose(handle);
		}
	    }
	}
    }

    if (errno == ENOTEMPTY) {
	/* 
	 * Posix allows both EEXIST or ENOTEMPTY, but we'll always
	 * return EEXIST to allow easy matching in Erlang code.
	 */

	errno = EEXIST;
    }

 end:
    return check_error(-1, errInfo);
}

int
efile_delete_file(errInfo, name)
Efile_error* errInfo;		/* Where to return error codes. */
char* name;			/* Name of file to delete. */
{
    DWORD attr;

    if (DeleteFile(name) != FALSE) {
	return 1;
    }

    errno = errno_map(GetLastError());
    if (errno == EACCES) {
        attr = GetFileAttributes(name);
	if (attr != (DWORD) -1) {
	    if (attr & FILE_ATTRIBUTE_DIRECTORY) {
		/*
		 * Windows NT reports removing a directory as EACCES instead
		 * of EPERM.
		 */

		errno = EPERM;
	    }
	}
    } else if (errno == ENOENT) {
        attr = GetFileAttributes(name);
	if (attr != (DWORD) -1) {
	    if (attr & FILE_ATTRIBUTE_DIRECTORY) {
	    	/*
		 * Windows 95 reports removing a directory as ENOENT instead 
		 * of EPERM.
		 */

		errno = EPERM;
	    }
	}
    } else if (errno == EINVAL) {
	/*
	 * Windows NT reports removing a char device as EINVAL instead of
	 * EACCES.
	 */
	
	errno = EACCES;
    }

    return check_error(-1, errInfo);
}

/*
 *---------------------------------------------------------------------------
 *
 *      Changes the name of an existing file or directory, from src to dst.
 *	If src and dst refer to the same file or directory, does nothing
 *	and returns success.  Otherwise if dst already exists, it will be
 *	deleted and replaced by src subject to the following conditions:
 *	    If src is a directory, dst may be an empty directory.
 *	    If src is a file, dst may be a file.
 *	In any other situation where dst already exists, the rename will
 *	fail.  
 *
 *	Some possible error codes:
 *
 *	EACCES:     src or dst parent directory can't be read and/or written.
 *	EEXIST:	    dst is a non-empty directory.
 *	EINVAL:	    src is a root directory or dst is a subdirectory of src.
 *	EISDIR:	    dst is a directory, but src is not.
 *	ENOENT:	    src doesn't exist, or src or dst is "".
 *	ENOTDIR:    src is a directory, but dst is not.  
 *	EXDEV:	    src and dst are on different filesystems.
 *	
 * Side effects:
 *	The implementation of rename may allow cross-filesystem renames,
 *	but the caller should be prepared to emulate it with copy and
 *	delete if errno is EXDEV.
 *
 *---------------------------------------------------------------------------
 */

int
efile_rename(errInfo, src, dst)
Efile_error* errInfo;		/* Where to return error codes. */
char* src;			/* Original name. */
char* dst;			/* New name. */
{
    DWORD srcAttr, dstAttr;
    
    if (MoveFile(src, dst) != FALSE) {
	return 1;
    }

    errno = errno_map(GetLastError());
    srcAttr = GetFileAttributes(src);
    dstAttr = GetFileAttributes(dst);
    if (srcAttr == (DWORD) -1) {
	srcAttr = 0;
    }
    if (dstAttr == (DWORD) -1) {
	dstAttr = 0;
    }

    if (errno == EBADF) {
	errno = EACCES;
	return check_error(-1, errInfo);
    }
    if (errno == EACCES) {
	decode:
	if (srcAttr & FILE_ATTRIBUTE_DIRECTORY) {
	    char srcPath[MAX_PATH], dstPath[MAX_PATH];
	    char *srcRest, *dstRest;
	    int size;

	    size = GetFullPathName(src, sizeof(srcPath), srcPath, &srcRest);
	    if ((size == 0) || (size > sizeof(srcPath))) {
		return check_error(-1, errInfo);
	    }
	    size = GetFullPathName(dst, sizeof(dstPath), dstPath, &dstRest);
	    if ((size == 0) || (size > sizeof(dstPath))) {
		return check_error(-1, errInfo);
	    }
	    if (srcRest == NULL) {
		srcRest = srcPath + strlen(srcPath);
	    }
	    if (strnicmp(srcPath, dstPath, srcRest - srcPath) == 0) {
		/*
		 * Trying to move a directory into itself.
		 */

		errno = EINVAL;
	    }
	    if (extract_root(srcPath)) {
		/*
		 * Attempt to move a root directory.  Never allowed.
		 */
		errno = EINVAL;
	    }

	    (void) extract_root(dstPath);
	    if (dstPath[0] == '\0') {
		/*
		 * The filename was invalid.  (Don't know why,
		 * but play it safe.)
		 */
		errno = EINVAL;
	    }
	    if (stricmp(srcPath, dstPath) != 0) {
		/*
		 * If src is a directory and dst filesystem != src
		 * filesystem, errno should be EXDEV.  It is very
		 * important to get this behavior, so that the caller
		 * can respond to a cross filesystem rename by
		 * simulating it with copy and delete.  The MoveFile
		 * system call already handles the case of moving a
		 * *file* between filesystems.
		 */

		errno = EXDEV;
	    }
	}

	/*
	 * Other types of access failure is that dst is a read-only
	 * filesystem, that an open file referred to src or dest, or that
	 * src or dest specified the current working directory on the
	 * current filesystem.  EACCES is returned for those cases.
	 */

    } else if (errno == EEXIST) {
	/*
	 * Reports EEXIST any time the target already exists.  If it makes
	 * sense, remove the old file and try renaming again.
	 */

	if (srcAttr & FILE_ATTRIBUTE_DIRECTORY) {
	    if (dstAttr & FILE_ATTRIBUTE_DIRECTORY) {
		/*
		 * Overwrite empty dst directory with src directory.  The
		 * following call will remove an empty directory.  If it
		 * fails, it's because it wasn't empty.
		 */

		if (RemoveDirectory(dst)) {
		    /*
		     * Now that that empty directory is gone, we can try
		     * renaming again.  If that fails, we'll put this empty
		     * directory back, for completeness.
		     */

		    if (MoveFile(src, dst) != FALSE) {
			return 1;