tclunixfcmd.c

linux系统下的音频通信

/*
 * tclUnixFCmd.c
 *
 *      This file implements the unix specific portion of file manipulation 
 *      subcommands of the "file" command.  All filename arguments should
 *	already be translated to native format.
 *
 * Copyright (c) 1996-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS: @(#) tclUnixFCmd.c 1.31 97/10/13 16:51:14
 *
 * Portions of this code were derived from NetBSD source code which has
 * the following copyright notice:
 *
 * Copyright (c) 1988, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "tclInt.h"
#include "tclPort.h"
#include <utime.h>
#include <grp.h>

/*
 * The following constants specify the type of callback when
 * TraverseUnixTree() calls the traverseProc()
 */

#define DOTREE_PRED   1     /* pre-order directory  */
#define DOTREE_POSTD  2     /* post-order directory */
#define DOTREE_F      3     /* regular file */

/*
 * Callbacks for file attributes code.
 */

static int		GetGroupAttribute _ANSI_ARGS_((Tcl_Interp *interp,
			    int objIndex, char *fileName,
			    Tcl_Obj **attributePtrPtr));
static int		GetOwnerAttribute _ANSI_ARGS_((Tcl_Interp *interp,
			    int objIndex, char *fileName,
			    Tcl_Obj **attributePtrPtr));
static int		GetPermissionsAttribute _ANSI_ARGS_((
			    Tcl_Interp *interp, int objIndex, char *fileName,
			    Tcl_Obj **attributePtrPtr));
static int		SetGroupAttribute _ANSI_ARGS_((Tcl_Interp *interp,
			    int objIndex, char *fileName,
			    Tcl_Obj *attributePtr));
static int		SetOwnerAttribute _ANSI_ARGS_((Tcl_Interp *interp,
			    int objIndex, char *fileName,
			    Tcl_Obj *attributePtr));
static int		SetPermissionsAttribute _ANSI_ARGS_((
			    Tcl_Interp *interp, int objIndex, char *fileName,
			    Tcl_Obj *attributePtr));
			  
/*
 * Prototype for the TraverseUnixTree callback function.
 */

typedef int (TraversalProc) _ANSI_ARGS_((char *src, char *dst, 
        struct stat *sb, int type, Tcl_DString *errorPtr));

/*
 * Constants and variables necessary for file attributes subcommand.
 */

enum {
    UNIX_GROUP_ATTRIBUTE,
    UNIX_OWNER_ATTRIBUTE,
    UNIX_PERMISSIONS_ATTRIBUTE
};

char *tclpFileAttrStrings[] = {"-group", "-owner", "-permissions",
	(char *) NULL};
CONST TclFileAttrProcs tclpFileAttrProcs[] = {
	{GetGroupAttribute, SetGroupAttribute},
	{GetOwnerAttribute, SetOwnerAttribute},
	{GetPermissionsAttribute, SetPermissionsAttribute}};

/*
 * Declarations for local procedures defined in this file:
 */

static int		CopyFile _ANSI_ARGS_((char *src, char *dst, 
			    struct stat *srcStatBufPtr));
static int		CopyFileAtts _ANSI_ARGS_((char *src, char *dst, 
			    struct stat *srcStatBufPtr));
static int		TraversalCopy _ANSI_ARGS_((char *src, char *dst, 
			    struct stat *sbPtr, int type,
			    Tcl_DString *errorPtr));
static int		TraversalDelete _ANSI_ARGS_((char *src, char *dst, 
			    struct stat *sbPtr, int type,
			    Tcl_DString *errorPtr));
static int		TraverseUnixTree _ANSI_ARGS_((
			    TraversalProc *traversalProc,
			    Tcl_DString *sourcePath, Tcl_DString *destPath,
			    Tcl_DString *errorPtr));

/*
 *---------------------------------------------------------------------------
 *
 * TclpRenameFile --
 *
 *      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.  
 *
 * Results:
 *	If the directory was successfully created, returns TCL_OK.
 *	Otherwise the return value is TCL_ERROR and errno is set to
 *	indicate the error.  Some possible values for errno are:
 *
 *	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
TclpRenameFile(src, dst)
    char *src;			/* Pathname of file or dir to be renamed. */
    char *dst;			/* New pathname of file or directory. */
{
    if (rename(src, dst) == 0) {
	return TCL_OK;
    }
    if (errno == ENOTEMPTY) {
	errno = EEXIST;
    }

#ifdef sparc
    /*
     * SunOS 4.1.4 reports overwriting a non-empty directory with a
     * directory as EINVAL instead of EEXIST (first rule out the correct
     * EINVAL result code for moving a directory into itself).  Must be
     * conditionally compiled because realpath() is only defined on SunOS.
     */

    if (errno == EINVAL) {
	char srcPath[MAXPATHLEN], dstPath[MAXPATHLEN];
	DIR *dirPtr;
	struct dirent *dirEntPtr;

	if ((realpath(src, srcPath) != NULL)
		&& (realpath(dst, dstPath) != NULL)
		&& (strncmp(srcPath, dstPath, strlen(srcPath)) != 0)) {
	    dirPtr = opendir(dst);
	    if (dirPtr != NULL) {
		while ((dirEntPtr = readdir(dirPtr)) != NULL) {
		    if ((strcmp(dirEntPtr->d_name, ".") != 0) &&
			    (strcmp(dirEntPtr->d_name, "..") != 0)) {
			errno = EEXIST;
			closedir(dirPtr);
			return TCL_ERROR;
		    }
		}
		closedir(dirPtr);
	    }
	}
	errno = EINVAL;
    }
#endif	/* sparc */

    if (strcmp(src, "/") == 0) {
	/*
	 * Alpha reports renaming / as EBUSY and Linux reports it as EACCES,
	 * instead of EINVAL.
	 */
	 
	errno = EINVAL;
    }

    /*
     * DEC Alpha OSF1 V3.0 returns EACCES when attempting to move a
     * file across filesystems and the parent directory of that file is
     * not writable.  Most other systems return EXDEV.  Does nothing to
     * correct this behavior.
     */

    return TCL_ERROR;
}


/*
 *---------------------------------------------------------------------------
 *
 * TclpCopyFile --
 *
 *      Copy a single file (not a directory).  If dst already exists and
 *	is not a directory, it is removed.
 *
 * Results:
 *	If the file was successfully copied, returns TCL_OK.  Otherwise
 *	the return value is TCL_ERROR and errno is set to indicate the
 *	error.  Some possible values for errno are:
 *
 *	EACCES:     src or dst parent directory can't be read and/or written.
 *	EISDIR:	    src or dst is a directory.
 *	ENOENT:	    src doesn't exist.  src or dst is "".
 *
 * Side effects:
 *      This procedure will also copy symbolic links, block, and
 *      character devices, and fifos.  For symbolic links, the links 
 *      themselves will be copied and not what they point to.  For the
 *	other special file types, the directory entry will be copied and
 *	not the contents of the device that it refers to.
 *
 *---------------------------------------------------------------------------
 */

int 
TclpCopyFile(src, dst)
    char *src;			/* Pathname of file to be copied. */
    char *dst;			/* Pathname of file to copy to. */
{
    struct stat srcStatBuf, dstStatBuf;
    char link[MAXPATHLEN];
    int length;

    /*
     * Have to do a stat() to determine the filetype.
     */
    
    if (lstat(src, &srcStatBuf) != 0) {
	return TCL_ERROR;
    }
    if (S_ISDIR(srcStatBuf.st_mode)) {
	errno = EISDIR;
	return TCL_ERROR;
    }

    /*
     * symlink, and some of the other calls will fail if the target 
     * exists, so we remove it first
     */
    
    if (lstat(dst, &dstStatBuf) == 0) {
	if (S_ISDIR(dstStatBuf.st_mode)) {
	    errno = EISDIR;
	    return TCL_ERROR;
	}
    }
    if (unlink(dst) != 0) {
	if (errno != ENOENT) {
	    return TCL_ERROR;
	} 
    }

    switch ((int) (srcStatBuf.st_mode & S_IFMT)) {
        case S_IFLNK:
	    length = readlink(src, link, sizeof(link)); 
	    if (length == -1) {
		return TCL_ERROR;
	    }
	    link[length] = '\0';
	    if (symlink(link, dst) < 0) {
		return TCL_ERROR;
	    }
	    break;

        case S_IFBLK:
        case S_IFCHR:
	    if (mknod(dst, srcStatBuf.st_mode, srcStatBuf.st_rdev) < 0) {
		return TCL_ERROR;
	    }
	    return CopyFileAtts(src, dst, &srcStatBuf);

        case S_IFIFO:
	    if (mkfifo(dst, srcStatBuf.st_mode) < 0) {
		return TCL_ERROR;
	    }
	    return CopyFileAtts(src, dst, &srcStatBuf);

        default:
	    return CopyFile(src, dst, &srcStatBuf);
    }
    
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * CopyFile - 
 *
 *      Helper function for TclpCopyFile.  Copies one regular file,
 *	using read() and write().
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *      A file is copied.  Dst will be overwritten if it exists.
 *
 *----------------------------------------------------------------------
 */

static int 
CopyFile(src, dst, srcStatBufPtr) 
    char *src;                   /* Pathname of file to copy. */
    char *dst;                   /* Pathname of file to create/overwrite. */
    struct stat *srcStatBufPtr;  /* Used to determine mode and blocksize */
{
    int srcFd;
    int dstFd;
    u_int blockSize;   /* Optimal I/O blocksize for filesystem */
    char *buffer;      /* Data buffer for copy */
    size_t nread;

    if ((srcFd = open(src, O_RDONLY, 0)) < 0) { 
	return TCL_ERROR;
    }

    dstFd = open(dst, O_CREAT | O_TRUNC | O_WRONLY, srcStatBufPtr->st_mode);
    if (dstFd < 0) {
	close(srcFd); 
	return TCL_ERROR;
    }

#if HAVE_ST_BLKSIZE
    blockSize = srcStatBufPtr->st_blksize;
#else
    blockSize = 4096;
#endif

    buffer = ckalloc(blockSize);
    while (1) {
	nread = read(srcFd, buffer, blockSize);
	if ((nread == -1) || (nread == 0)) {
	    break;
	}
	if (write(dstFd, buffer, nread) != nread) {
	    nread = (size_t) -1;
	    break;
	}
    }
	
    ckfree(buffer);
    close(srcFd);
    if ((close(dstFd) != 0) || (nread == -1)) {
	unlink(dst);
	return TCL_ERROR;
    }
    if (CopyFileAtts(src, dst, srcStatBufPtr) == TCL_ERROR) {
	/*
	 * The copy succeeded, but setting the permissions failed, so be in
	 * a consistent state, we remove the file that was created by the
	 * copy.
	 */

	unlink(dst);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *---------------------------------------------------------------------------
 *
 * TclpDeleteFile --
 *
 *      Removes a single file (not a directory).
 *