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/*

 * tclIOUtil.c --

 *

 *      This file contains a collection of utility procedures that

 *      are shared by the platform specific IO drivers.

 *

 *      Parts of this file are based on code contributed by Karl

 *      Lehenbauer, Mark Diekhans and Peter da Silva.

 *

 * Copyright (c) 1991-1994 The Regents of the University of California.

 * Copyright (c) 1994-1996 Sun Microsystems, Inc.

 *

 * See the file "license.terms" for information on usage and redistribution

 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

 *

 * RCS: @(#) $Id: tclIOUtil.c,v 1.1.1.1 2002-01-16 10:25:27 markom Exp $

 */

#include "tclInt.h"

#include "tclPort.h"

/*

 * The following typedef declarations allow for hooking into the chain

 * of functions maintained for 'Tcl_Stat(...)', 'Tcl_Access(...)' &

 * 'Tcl_OpenFileChannel(...)'.  Basically for each hookable function

 * a linked list is defined.

 */

typedef struct StatProc {

    TclStatProc_ *proc;          /* Function to process a 'stat()' call */

    struct StatProc *nextPtr;    /* The next 'stat()' function to call */

} StatProc;

typedef struct AccessProc {

    TclAccessProc_ *proc;        /* Function to process a 'access()' call */

    struct AccessProc *nextPtr;  /* The next 'access()' function to call */

} AccessProc;

typedef struct OpenFileChannelProc {

    TclOpenFileChannelProc_ *proc;  /* Function to process a

                                     * 'Tcl_OpenFileChannel()' call */

    struct OpenFileChannelProc *nextPtr;

                                    /* The next 'Tcl_OpenFileChannel()'

                                     * function to call */

} OpenFileChannelProc;

/*

 * For each type of hookable function, a static node is declared to

 * hold the function pointer for the "built-in" routine (e.g.

 * 'TclpStat(...)') and the respective list is initialized as a pointer

 * to that node.

 *

 * The "delete" functions (e.g. 'TclStatDeleteProc(...)') ensure that

 * these statically declared list entry cannot be inadvertently removed.

 *

 * This method avoids the need to call any sort of "initialization"

 * function

 */

static StatProc defaultStatProc = {

    &TclpStat, NULL

};

static StatProc *statProcList = &defaultStatProc;

static AccessProc defaultAccessProc = {

    &TclpAccess, NULL

};

static AccessProc *accessProcList = &defaultAccessProc;

static OpenFileChannelProc defaultOpenFileChannelProc = {

    &TclpOpenFileChannel, NULL

};

static OpenFileChannelProc *openFileChannelProcList =

        &defaultOpenFileChannelProc;

/*

 *----------------------------------------------------------------------

 *

 * TclGetOpenMode --

 *

 * Description:

 *      Computes a POSIX mode mask for opening a file, from a given string,

 *      and also sets a flag to indicate whether the caller should seek to

 *      EOF after opening the file.

 *

 * Results:

 *      On success, returns mode to pass to "open". If an error occurs, the

 *      returns -1 and if interp is not NULL, sets interp->result to an

 *      error message.

 *

 * Side effects:

 *      Sets the integer referenced by seekFlagPtr to 1 to tell the caller

 *      to seek to EOF after opening the file.

 *

 * Special note:

 *      This code is based on a prototype implementation contributed

 *      by Mark Diekhans.

 *

 *----------------------------------------------------------------------

 */

int

TclGetOpenMode(interp, string, seekFlagPtr)

    Tcl_Interp *interp;                 /* Interpreter to use for error

                                         * reporting - may be NULL. */

    char *string;                       /* Mode string, e.g. "r+" or

                                         * "RDONLY CREAT". */

    int *seekFlagPtr;                   /* Set this to 1 if the caller

                                         * should seek to EOF during the

                                         * opening of the file. */

{

    int mode, modeArgc, c, i, gotRW;

    char **modeArgv, *flag;

#define RW_MODES (O_RDONLY|O_WRONLY|O_RDWR)

    /*

     * Check for the simpler fopen-like access modes (e.g. "r").  They

     * are distinguished from the POSIX access modes by the presence

     * of a lower-case first letter.

     */

    *seekFlagPtr = 0;

    mode = 0;

    if (islower(UCHAR(string[0]))) {

        switch (string[0]) {

            case 'r':

                mode = O_RDONLY;

                break;

            case 'w':

                mode = O_WRONLY|O_CREAT|O_TRUNC;

                break;

            case 'a':

                mode = O_WRONLY|O_CREAT;

                *seekFlagPtr = 1;

                break;

            default:

                error:

                if (interp != (Tcl_Interp *) NULL) {

                    Tcl_AppendResult(interp,

                            "illegal access mode \"", string, "\"",

                            (char *) NULL);

                }

                return -1;

        }

        if (string[1] == '+') {

            mode &= ~(O_RDONLY|O_WRONLY);

            mode |= O_RDWR;

            if (string[2] != 0) {

                goto error;

            }

        } else if (string[1] != 0) {

            goto error;

        }

        return mode;

    }

    /*

     * The access modes are specified using a list of POSIX modes

     * such as O_CREAT.

     *

     * IMPORTANT NOTE: We rely on Tcl_SplitList working correctly when

     * a NULL interpreter is passed in.

     */

    if (Tcl_SplitList(interp, string, &modeArgc, &modeArgv) != TCL_OK) {

        if (interp != (Tcl_Interp *) NULL) {

            Tcl_AddErrorInfo(interp,

                    "\n    while processing open access modes \"");

            Tcl_AddErrorInfo(interp, string);

            Tcl_AddErrorInfo(interp, "\"");

        }

        return -1;

    }

    gotRW = 0;

    for (i = 0; i < modeArgc; i++) {

        flag = modeArgv[i];

        c = flag[0];

        if ((c == 'R') && (strcmp(flag, "RDONLY") == 0)) {

            mode = (mode & ~RW_MODES) | O_RDONLY;

            gotRW = 1;

        } else if ((c == 'W') && (strcmp(flag, "WRONLY") == 0)) {

            mode = (mode & ~RW_MODES) | O_WRONLY;

            gotRW = 1;

        } else if ((c == 'R') && (strcmp(flag, "RDWR") == 0)) {

            mode = (mode & ~RW_MODES) | O_RDWR;

            gotRW = 1;

        } else if ((c == 'A') && (strcmp(flag, "APPEND") == 0)) {

            mode |= O_APPEND;

            *seekFlagPtr = 1;

        } else if ((c == 'C') && (strcmp(flag, "CREAT") == 0)) {

            mode |= O_CREAT;

        } else if ((c == 'E') && (strcmp(flag, "EXCL") == 0)) {

            mode |= O_EXCL;

        } else if ((c == 'N') && (strcmp(flag, "NOCTTY") == 0)) {

#ifdef O_NOCTTY

            mode |= O_NOCTTY;

#else

            if (interp != (Tcl_Interp *) NULL) {

                Tcl_AppendResult(interp, "access mode \"", flag,

                        "\" not supported by this system", (char *) NULL);

            }

            ckfree((char *) modeArgv);

            return -1;

#endif

        } else if ((c == 'N') && (strcmp(flag, "NONBLOCK") == 0)) {

#if defined(O_NDELAY) || defined(O_NONBLOCK)

#   ifdef O_NONBLOCK

            mode |= O_NONBLOCK;

#   else

            mode |= O_NDELAY;

#   endif

#else

            if (interp != (Tcl_Interp *) NULL) {

                Tcl_AppendResult(interp, "access mode \"", flag,

                        "\" not supported by this system", (char *) NULL);

            }

            ckfree((char *) modeArgv);

            return -1;

#endif

        } else if ((c == 'T') && (strcmp(flag, "TRUNC") == 0)) {

            mode |= O_TRUNC;

        } else {

            if (interp != (Tcl_Interp *) NULL) {

                Tcl_AppendResult(interp, "invalid access mode \"", flag,

                        "\": must be RDONLY, WRONLY, RDWR, APPEND, CREAT",

                        " EXCL, NOCTTY, NONBLOCK, or TRUNC", (char *) NULL);

            }

            ckfree((char *) modeArgv);

            return -1;

        }

    }

    ckfree((char *) modeArgv);

    if (!gotRW) {

        if (interp != (Tcl_Interp *) NULL) {

            Tcl_AppendResult(interp, "access mode must include either",

                    " RDONLY, WRONLY, or RDWR", (char *) NULL);

        }

        return -1;

    }

    return mode;

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_EvalFile --

 *

 *      Read in a file and process the entire file as one gigantic

 *      Tcl command.

 *

 * Results:

 *      A standard Tcl result, which is either the result of executing

 *      the file or an error indicating why the file couldn't be read.

 *

 * Side effects:

 *      Depends on the commands in the file.

 *

 *----------------------------------------------------------------------

 */

int

Tcl_EvalFile(interp, fileName)

    Tcl_Interp *interp;         /* Interpreter in which to process file. */

    char *fileName;             /* Name of file to process.  Tilde-substitution

                                 * will be performed on this name. */

{

    int result;

    struct stat statBuf;

    char *cmdBuffer = (char *) NULL;

    char *oldScriptFile;

    Interp *iPtr = (Interp *) interp;

    Tcl_DString buffer;

    char *nativeName;

    Tcl_Channel chan;

    Tcl_Obj *cmdObjPtr;

    Tcl_ResetResult(interp);

    oldScriptFile = iPtr->scriptFile;

    iPtr->scriptFile = fileName;

    Tcl_DStringInit(&buffer);

    nativeName = Tcl_TranslateFileName(interp, fileName, &buffer);

    if (nativeName == NULL) {

        goto error;

    }

    /*

     * If Tcl_TranslateFileName didn't already copy the file name, do it

     * here.  This way we don't depend on fileName staying constant

     * throughout the execution of the script (e.g., what if it happens

     * to point to a Tcl variable that the script could change?).

     */

    if (nativeName != Tcl_DStringValue(&buffer)) {

        Tcl_DStringSetLength(&buffer, 0);

        Tcl_DStringAppend(&buffer, nativeName, -1);

        nativeName = Tcl_DStringValue(&buffer);

    }

    if (TclStat(nativeName, &statBuf) == -1) {

        Tcl_SetErrno(errno);

        Tcl_AppendResult(interp, "couldn't read file \"", fileName,

                "\": ", Tcl_PosixError(interp), (char *) NULL);

        goto error;

    }

    chan = Tcl_OpenFileChannel(interp, nativeName, "r", 0644);

    if (chan == (Tcl_Channel) NULL) {

        Tcl_ResetResult(interp);

        Tcl_AppendResult(interp, "couldn't read file \"", fileName,

                "\": ", Tcl_PosixError(interp), (char *) NULL);

        goto error;

    }

    cmdBuffer = (char *) ckalloc((unsigned) statBuf.st_size+1);

    result = Tcl_Read(chan, cmdBuffer, statBuf.st_size);

    if (result < 0) {

        Tcl_Close(interp, chan);

        Tcl_AppendResult(interp, "couldn't read file \"", fileName,

                "\": ", Tcl_PosixError(interp), (char *) NULL);

        goto error;

    }

    cmdBuffer[result] = 0;

    if (Tcl_Close(interp, chan) != TCL_OK) {

        goto error;

    }

    /*

     * Transfer the buffer memory allocated above to the object system.

     * Tcl_EvalObj will own this new string object if needed,

     * so past the Tcl_EvalObj point, we must not ckfree(cmdBuffer)

     * but rather use the reference counting mechanism.

     * (Nb: and we must not thus not use goto error after this point)

     */

    cmdObjPtr = Tcl_NewObj();

    cmdObjPtr->bytes = cmdBuffer;

    cmdObjPtr->length = result;

    Tcl_IncrRefCount(cmdObjPtr);

    result = Tcl_EvalObj(interp, cmdObjPtr);

    Tcl_DecrRefCount(cmdObjPtr);

    if (result == TCL_RETURN) {

        result = TclUpdateReturnInfo(iPtr);

    } else if (result == TCL_ERROR) {

        char msg[200];

        /*

         * Record information telling where the error occurred.

         */

        sprintf(msg, "\n    (file \"%.150s\" line %d)", fileName,

                interp->errorLine);

        Tcl_AddErrorInfo(interp, msg);

    }

    iPtr->scriptFile = oldScriptFile;

    Tcl_DStringFree(&buffer);

    return result;

error:

    if (cmdBuffer != (char *) NULL) {

        ckfree(cmdBuffer);

    }

    iPtr->scriptFile = oldScriptFile;

    Tcl_DStringFree(&buffer);

    return TCL_ERROR;

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_GetErrno --

 *

 *      Gets the current value of the Tcl error code variable. This is

 *      currently the global variable "errno" but could in the future

 *      change to something else.

 *

 * Results:

 *      The value of the Tcl error code variable.

 *

 * Side effects:

 *      None. Note that the value of the Tcl error code variable is

 *      UNDEFINED if a call to Tcl_SetErrno did not precede this call.

 *

 *----------------------------------------------------------------------

 */

int

Tcl_GetErrno()

{

    return errno;

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_SetErrno --

 *

 *      Sets the Tcl error code variable to the supplied value.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Modifies the value of the Tcl error code variable.

 *

 *----------------------------------------------------------------------

 */

void

Tcl_SetErrno(err)

    int err;                    /* The new value. */

{

    errno = err;

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_PosixError --

 *

 *      This procedure is typically called after UNIX kernel calls

 *      return errors.  It stores machine-readable information about

 *      the error in $errorCode returns an information string for

 *      the caller's use.

 *

 * Results:

 *      The return value is a human-readable string describing the

 *      error.

 *

 * Side effects:

 *      The global variable $errorCode is reset.

 *

 *----------------------------------------------------------------------

 */

char *

Tcl_PosixError(interp)

    Tcl_Interp *interp;         /* Interpreter whose $errorCode variable

                                 * is to be changed. */

{

    char *id, *msg;

    msg = Tcl_ErrnoMsg(errno);

    id = Tcl_ErrnoId();

    Tcl_SetErrorCode(interp, "POSIX", id, msg, (char *) NULL);

    return msg;

}

/*

 *----------------------------------------------------------------------

 *

 * TclStat --

 *

 *      This procedure replaces the library version of stat and lsat.

 *      The chain of functions that have been "inserted" into the

 *      'statProcList' will be called in succession until either

 *      a value of zero is returned, or the entire list is visited.

 *

 * Results:

 *      See stat documentation.

 *

 * Side effects:

 *      See stat documentation.

 *

 *----------------------------------------------------------------------

 */

int

TclStat(path, buf)

    CONST char *path;           /* Path of file to stat (in current CP). */

    TclStat_ *buf;              /* Filled with results of stat call. */

{

    StatProc *statProcPtr = statProcList;

    int retVal = -1;

    /*

     * Call each of the "stat" function in succession.  A non-return

     * value of -1 indicates the particular function has succeeded.

     */

    while ((retVal == -1) && (statProcPtr != NULL)) {

        retVal = (*statProcPtr->proc)(path, buf);

        statProcPtr = statProcPtr->nextPtr;

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * TclAccess --

 *

 *      This procedure replaces the library version of access.

 *      The chain of functions that have been "inserted" into the

 *      'accessProcList' will be called in succession until either

 *      a value of zero is returned, or the entire list is visited.

 *

 * Results:

 *      See access documentation.

 *

 * Side effects:

 *      See access documentation.

 *

 *----------------------------------------------------------------------

 */

int

TclAccess(path, mode)

    CONST char *path;           /* Path of file to access (in current CP). */

    int mode;                   /* Permission setting. */

{

    AccessProc *accessProcPtr = accessProcList;

    int retVal = -1;

    /*

     * Call each of the "access" function in succession.  A non-return

     * value of -1 indicates the particular function has succeeded.

     */

    while ((retVal == -1) && (accessProcPtr != NULL)) {

        retVal = (*accessProcPtr->proc)(path, mode);

        accessProcPtr = accessProcPtr->nextPtr;

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_OpenFileChannel --

 *

 *      The chain of functions that have been "inserted" into the

 *      'openFileChannelProcList' will be called in succession until

 *      either a valid file channel is returned, or the entire list is

 *      visited.

 *

 * Results:

 *      The new channel or NULL, if the named file could not be opened.

 *

 * Side effects:

 *      May open the channel and may cause creation of a file on the

 *      file system.

 *

 *----------------------------------------------------------------------

 */

Tcl_Channel

Tcl_OpenFileChannel(interp, fileName, modeString, permissions)

    Tcl_Interp *interp;                 /* Interpreter for error reporting;

                                         * can be NULL. */

    char *fileName;                     /* Name of file to open. */

    char *modeString;                   /* A list of POSIX open modes or

                                         * a string such as "rw". */

    int permissions;                    /* If the open involves creating a

                                         * file, with what modes to create

                                         * it? */

{

    OpenFileChannelProc *openFileChannelProcPtr = openFileChannelProcList;

    Tcl_Channel retVal = NULL;

    /*

     * Call each of the "Tcl_OpenFileChannel" function in succession.

     * A non-NULL return value indicates the particular function has

     * succeeded.

     */

    while ((retVal == NULL) && (openFileChannelProcPtr != NULL)) {

        retVal = (*openFileChannelProcPtr->proc)(interp, fileName,

                modeString, permissions);

        openFileChannelProcPtr = openFileChannelProcPtr->nextPtr;

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * TclStatInsertProc --

 *

 *      Insert the passed procedure pointer at the head of the list of

 *      functions which are used during a call to 'TclStat(...)'. The

 *      passed function should be have exactly like 'TclStat' when called

 *      during that time (see 'TclStat(...)' for more informatin).

 *      The function will be added even if it already in the list.

 *

 * Results:

 *      Normally TCL_OK; TCL_ERROR if memory for a new node in the list

 *      could not be allocated.

 *

 * Side effects:

 *      Memory allocataed and modifies the link list for 'TclStat'

 *      functions.

 *

 *----------------------------------------------------------------------

 */

int

TclStatInsertProc (proc)

    TclStatProc_ *proc;

{

    int retVal = TCL_ERROR;

    if (proc != NULL) {

        StatProc *newStatProcPtr;

        newStatProcPtr = (StatProc *)Tcl_Alloc(sizeof(StatProc));;

        if (newStatProcPtr != NULL) {

            newStatProcPtr->proc = proc;

            newStatProcPtr->nextPtr = statProcList;

            statProcList = newStatProcPtr;

            retVal = TCL_OK;

        }

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * TclStatDeleteProc --

 *

 *      Removed the passed function pointer from the list of 'TclStat'

 *      functions.  Ensures that the built-in stat function is not

 *      removvable.

 *

 * Results:

 *      TCL_OK if the procedure pointer was successfully removed,

 *      TCL_ERROR otherwise.

 *

 * Side effects:

 *      Memory is deallocated and the respective list updated.

 *

 *----------------------------------------------------------------------

 */

int

TclStatDeleteProc (proc)

    TclStatProc_ *proc;

{

    int retVal = TCL_ERROR;

    StatProc *tmpStatProcPtr = statProcList;

    StatProc *prevStatProcPtr = NULL;

    /*

     * Traverse the 'statProcList' looking for the particular node

     * whose 'proc' member matches 'proc' and remove that one from

     * the list.  Ensure that the "default" node cannot be removed.

     */

    while ((retVal == TCL_ERROR) && (tmpStatProcPtr != &defaultStatProc)) {

        if (tmpStatProcPtr->proc == proc) {

            if (prevStatProcPtr == NULL) {

                statProcList = tmpStatProcPtr->nextPtr;

            } else {

                prevStatProcPtr->nextPtr = tmpStatProcPtr->nextPtr;

            }

            Tcl_Free((char *)tmpStatProcPtr);

            retVal = TCL_OK;

        } else {

            prevStatProcPtr = tmpStatProcPtr;

            tmpStatProcPtr = tmpStatProcPtr->nextPtr;

        }

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * TclAccessInsertProc --

 *

 *      Insert the passed procedure pointer at the head of the list of

 *      functions which are used during a call to 'TclAccess(...)'. The

 *      passed function should be have exactly like 'TclAccess' when

 *      called during that time (see 'TclAccess(...)' for more informatin).

 *      The function will be added even if it already in the list.

 *

 * Results:

 *      Normally TCL_OK; TCL_ERROR if memory for a new node in the list

 *      could not be allocated.

 *

 * Side effects:

 *      Memory allocataed and modifies the link list for 'TclAccess'

 *      functions.

 *

 *----------------------------------------------------------------------

 */

int

TclAccessInsertProc(proc)

    TclAccessProc_ *proc;

{

    int retVal = TCL_ERROR;

    if (proc != NULL) {

        AccessProc *newAccessProcPtr;

        newAccessProcPtr = (AccessProc *)Tcl_Alloc(sizeof(AccessProc));;

        if (newAccessProcPtr != NULL) {

            newAccessProcPtr->proc = proc;

            newAccessProcPtr->nextPtr = accessProcList;

            accessProcList = newAccessProcPtr;

            retVal = TCL_OK;

        }

    }

    return (retVal);

}

/*

 *----------------------------------------------------------------------

 *

 * TclAccessDeleteProc --

 *

 *      Removed the passed function pointer from the list of 'TclAccess'

 *      functions.  Ensures that the built-in access function is not

 *      removvable.

 *

 * Results:

 *      TCL_OK if the procedure pointer was successfully removed,

 *      TCL_ERROR otherwise.

 *