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/* File tree walker functions.

   Copyright (C) 1996-2001, 2002, 2003 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, write to the Free

   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

   02111-1307 USA.  */

#define _GNU_SOURCE

#include <features.h>

#if defined (__UCLIBC_HAS_LFS__) && defined L_ftw64

#define L_ftw

/* If Large file support is enabled, transparently remap

 * things to use the 64-bit interfaces */

#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS != 64 

#undef _FILE_OFFSET_BITS

#define _FILE_OFFSET_BITS   64

#endif

#ifndef __USE_LARGEFILE64

# define __USE_LARGEFILE64  1

#endif

#ifndef __USE_FILE_OFFSET64

# define __USE_FILE_OFFSET64  1

#endif

#define FTW_NAME ftw64

#define NFTW_NAME nftw64

#define INO_T ino64_t

#define STAT stat64

#define LSTAT lstat64

#define XSTAT stat64

#define FTW_FUNC_T __ftw64_func_t

#define NFTW_FUNC_T __nftw64_func_t

#else

#define FTW_NAME ftw

#define NFTW_NAME nftw

#define INO_T ino_t

#define STAT stat

#define LSTAT lstat

#define XSTAT stat

#define FTW_FUNC_T __ftw_func_t

#define NFTW_FUNC_T __nftw_func_t

#endif

#ifdef L_ftw

#include <alloca.h>

#include <errno.h>

#include <ftw.h>

#include <limits.h>

#include <search.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/param.h>

#include <sys/stat.h>

#include <assert.h>

#include <dirent.h>

/* We define PATH_MAX if the system does not provide a definition.

   This does not artificially limit any operation.  PATH_MAX is simply

   used as a guesstimate for the expected maximal path length.

   Buffers will be enlarged if necessary.  */

#ifndef PATH_MAX

# define PATH_MAX 1024

#endif

struct dir_data

{

    DIR *stream;

    char *content;

};

struct known_object

{

    dev_t dev;

    INO_T ino;

};

struct ftw_data

{

    /* Array with pointers to open directory streams.  */

    struct dir_data **dirstreams;

    size_t actdir;

    size_t maxdir;

    /* Buffer containing name of currently processed object.  */

    char *dirbuf;

    size_t dirbufsize;

    /* Passed as fourth argument to `nftw' callback.  The `base' member

       tracks the content of the `dirbuf'.  */

    struct FTW ftw;

    /* Flags passed to `nftw' function.  0 for `ftw'.  */

    int flags;

    /* Conversion array for flag values.  It is the identity mapping for

       `nftw' calls, otherwise it maps the values to those known by

       `ftw'.  */

    const int *cvt_arr;

    /* Callback function.  We always use the `nftw' form.  */

    NFTW_FUNC_T func;

    /* Device of starting point.  Needed for FTW_MOUNT.  */

    dev_t dev;

    /* Data structure for keeping fingerprints of already processed

       object.  This is needed when not using FTW_PHYS.  */

    void *known_objects;

};

/* Internally we use the FTW_* constants used for `nftw'.  When invoked

   as `ftw', map each flag to the subset of values used by `ftw'.  */

static const int nftw_arr[] =

{

    FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_SL, FTW_DP, FTW_SLN

};

static const int ftw_arr[] =

{

    FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_F, FTW_D, FTW_NS

};

/* Forward declarations of local functions.  */

static int ftw_dir (struct ftw_data *data, struct STAT *st) internal_function;

static int

object_compare (const void *p1, const void *p2)

{

    /* We don't need a sophisticated and useful comparison.  We are only

       interested in equality.  However, we must be careful not to

       accidentally compare `holes' in the structure.  */

    const struct known_object *kp1 = p1, *kp2 = p2;

    int cmp1;

    cmp1 = (kp1->ino > kp2->ino) - (kp1->ino < kp2->ino);

    if (cmp1 != 0)

        return cmp1;

    return (kp1->dev > kp2->dev) - (kp1->dev < kp2->dev);

}

static inline int

add_object (struct ftw_data *data, struct STAT *st)

{

    struct known_object *newp = malloc (sizeof (struct known_object));

    if (newp == NULL)

        return -1;

    newp->dev = st->st_dev;

    newp->ino = st->st_ino;

    return tsearch (newp, &data->known_objects, object_compare) ? 0 : -1;

}

static inline int

find_object (struct ftw_data *data, struct STAT *st)

{

    struct known_object obj;

    obj.dev = st->st_dev;

    obj.ino = st->st_ino;

    return tfind (&obj, &data->known_objects, object_compare) != NULL;

}

static inline int

__attribute ((always_inline))

open_dir_stream (struct ftw_data *data, struct dir_data *dirp)

{

    int result = 0;

    if (data->dirstreams[data->actdir] != NULL)

    {

        /* Oh, oh.  We must close this stream.  Get all remaining

           entries and store them as a list in the `content' member of

           the `struct dir_data' variable.  */

        size_t bufsize = 1024;

        char *buf = malloc (bufsize);

        if (buf == NULL)

            result = -1;

        else

        {

            DIR *st = data->dirstreams[data->actdir]->stream;

            struct dirent *d;

            size_t actsize = 0;

            while ((d = readdir (st)) != NULL)

            {

                size_t this_len = _D_EXACT_NAMLEN (d);

                if (actsize + this_len + 2 >= bufsize)

                {

                    char *newp;

                    bufsize += MAX (1024, 2 * this_len);

                    newp = (char *) realloc (buf, bufsize);

                    if (newp == NULL)

                    {

                        /* No more memory.  */

                        int save_err = errno;

                        free (buf);

                        __set_errno (save_err);

                        result = -1;

                        break;

                    }

                    buf = newp;

                }

                *((char *) mempcpy (buf + actsize, d->d_name, this_len))

                    = '\0';

                actsize += this_len + 1;

            }

            /* Terminate the list with an additional NUL byte.  */

            buf[actsize++] = '\0';

            /* Shrink the buffer to what we actually need.  */

            data->dirstreams[data->actdir]->content = realloc (buf, actsize);

            if (data->dirstreams[data->actdir]->content == NULL)

            {

                int save_err = errno;

                free (buf);

                __set_errno (save_err);

                result = -1;

            }

            else

            {

                closedir (st);

                data->dirstreams[data->actdir]->stream = NULL;

                data->dirstreams[data->actdir] = NULL;

            }

        }

    }

    /* Open the new stream.  */

    if (result == 0)

    {

        const char *name = ((data->flags & FTW_CHDIR)

                ? data->dirbuf + data->ftw.base: data->dirbuf);

        assert (data->dirstreams[data->actdir] == NULL);

        dirp->stream = opendir (name);

        if (dirp->stream == NULL)

            result = -1;

        else

        {

            dirp->content = NULL;

            data->dirstreams[data->actdir] = dirp;

            if (++data->actdir == data->maxdir)

                data->actdir = 0;

        }

    }

    return result;

}

static int

internal_function

process_entry (struct ftw_data *data, struct dir_data *dir, const char *name, size_t namlen)

{

    struct STAT st;

    int result = 0;

    int flag = 0;

    size_t new_buflen;

    if (name[0] == '.' && (name[1] == '\0'

                || (name[1] == '.' && name[2] == '\0')))

        /* Don't process the "." and ".." entries.  */

        return 0;

    new_buflen = data->ftw.base + namlen + 2;

    if (data->dirbufsize < new_buflen)

    {

        /* Enlarge the buffer.  */

        char *newp;

        data->dirbufsize = 2 * new_buflen;

        newp = (char *) realloc (data->dirbuf, data->dirbufsize);

        if (newp == NULL)

            return -1;

        data->dirbuf = newp;

    }

    *((char *) mempcpy (data->dirbuf + data->ftw.base, name, namlen)) = '\0';

    if ((data->flags & FTW_CHDIR) == 0)

        name = data->dirbuf;

    if (((data->flags & FTW_PHYS)

                ? LSTAT (name, &st)

                : XSTAT (name, &st)) < 0)

    {

        if (errno != EACCES && errno != ENOENT)

            result = -1;

        else if (!(data->flags & FTW_PHYS)

                && LSTAT (name, &st) == 0

                && S_ISLNK (st.st_mode))

            flag = FTW_SLN;

        else

            flag = FTW_NS;

    }

    else

    {

        if (S_ISDIR (st.st_mode))

            flag = FTW_D;

        else if (S_ISLNK (st.st_mode))

            flag = FTW_SL;

        else

            flag = FTW_F;

    }

    if (result == 0

            && (flag == FTW_NS

                || !(data->flags & FTW_MOUNT) || st.st_dev == data->dev))

    {

        if (flag == FTW_D)

        {

            if ((data->flags & FTW_PHYS)

                    || (!find_object (data, &st)

                        /* Remember the object.  */

                        && (result = add_object (data, &st)) == 0))

            {

                result = ftw_dir (data, &st);

                if (result == 0 && (data->flags & FTW_CHDIR))

                {

                    /* Change back to the parent directory.  */

                    int done = 0;

                    if (dir->stream != NULL)

                        if (fchdir (dirfd (dir->stream)) == 0)

                            done = 1;

                    if (!done)

                    {

                        if (data->ftw.base == 1)

                        {

                            if (chdir ("/") < 0)

                                result = -1;

                        }

                        else

                            if (chdir ("..") < 0)

                                result = -1;

                    }

                }

            }

        }

        else

            result = (*data->func) (data->dirbuf, &st, data->cvt_arr[flag],

                    &data->ftw);

    }

    return result;

}

static int

internal_function

ftw_dir (struct ftw_data *data, struct STAT *st)

{

    struct dir_data dir;

    struct dirent *d;

    int previous_base = data->ftw.base;

    int result;

    char *startp;

    /* Open the stream for this directory.  This might require that

       another stream has to be closed.  */

    result = open_dir_stream (data, &dir);

    if (result != 0)

    {

        if (errno == EACCES)

            /* We cannot read the directory.  Signal this with a special flag.  */

            result = (*data->func) (data->dirbuf, st, FTW_DNR, &data->ftw);

        return result;

    }

    /* First, report the directory (if not depth-first).  */

    if (!(data->flags & FTW_DEPTH))

    {

        result = (*data->func) (data->dirbuf, st, FTW_D, &data->ftw);

        if (result != 0)

            return result;

    }

    /* If necessary, change to this directory.  */

    if (data->flags & FTW_CHDIR)

    {

        if (fchdir (dirfd (dir.stream)) < 0)

        {

            int save_err = errno;

            closedir (dir.stream);

            __set_errno (save_err);

            if (data->actdir-- == 0)

                data->actdir = data->maxdir - 1;

            data->dirstreams[data->actdir] = NULL;

            return -1;

        }

    }

    /* Next, update the `struct FTW' information.  */

    ++data->ftw.level;

    startp = strchr (data->dirbuf, '\0');

    /* There always must be a directory name.  */

    assert (startp != data->dirbuf);

    if (startp[-1] != '/')

        *startp++ = '/';

    data->ftw.base = startp - data->dirbuf;

    while (dir.stream != NULL && (d = readdir (dir.stream)) != NULL)

    {

        result = process_entry (data, &dir, d->d_name, _D_EXACT_NAMLEN (d));

        if (result != 0)

            break;

    }

    if (dir.stream != NULL)

    {

        /* The stream is still open.  I.e., we did not need more

           descriptors.  Simply close the stream now.  */

        int save_err = errno;

        assert (dir.content == NULL);

        closedir (dir.stream);

        __set_errno (save_err);

        if (data->actdir-- == 0)

            data->actdir = data->maxdir - 1;

        data->dirstreams[data->actdir] = NULL;

    }

    else

    {

        int save_err;

        char *runp = dir.content;

        while (result == 0 && *runp != '\0')

        {

            char *endp = strchr (runp, '\0');

            result = process_entry (data, &dir, runp, endp - runp);

            runp = endp + 1;

        }

        save_err = errno;

        free (dir.content);

        __set_errno (save_err);

    }

    /* Prepare the return, revert the `struct FTW' information.  */

    data->dirbuf[data->ftw.base - 1] = '\0';

    --data->ftw.level;

    data->ftw.base = previous_base;

    /* Finally, if we process depth-first report the directory.  */

    if (result == 0 && (data->flags & FTW_DEPTH))

        result = (*data->func) (data->dirbuf, st, FTW_DP, &data->ftw);

    return result;

}

static int

internal_function

ftw_startup (const char *dir, int is_nftw, void *func, int descriptors, int flags)

{

    struct ftw_data data;

    struct STAT st;

    int result = 0;

    int save_err;

    char *cwd = NULL;

    char *cp;

    /* First make sure the parameters are reasonable.  */

    if (unlikely(dir==NULL || *dir=='\0')) {

        __set_errno (ENOENT);

        return -1;

    }

    if ((strlen(dir)+1) > NAME_MAX) {

        __set_errno(ENAMETOOLONG);

        return -1;

    }

    data.maxdir = descriptors < 1 ? 1 : descriptors;

    data.actdir = 0;

    data.dirstreams = (struct dir_data **) alloca (data.maxdir

            * sizeof (struct dir_data *));

    memset (data.dirstreams, '\0', data.maxdir * sizeof (struct dir_data *));

    /* PATH_MAX is always defined when we get here.  */

    data.dirbufsize = MAX (2 * strlen (dir), PATH_MAX);

    data.dirbuf = (char *) malloc (data.dirbufsize);

    if (data.dirbuf == NULL)

        return -1;

    cp = stpcpy (data.dirbuf, dir);

    /* Strip trailing slashes.  */

    while (cp > data.dirbuf + 1 && cp[-1] == '/')

        --cp;

    *cp = '\0';

    data.ftw.level = 0;

    /* Find basename.  */

    while (cp > data.dirbuf && cp[-1] != '/')

        --cp;

    data.ftw.base = cp - data.dirbuf;

    data.flags = flags;

    /* This assignment might seem to be strange but it is what we want.

       The trick is that the first three arguments to the `ftw' and

       `nftw' callback functions are equal.  Therefore we can call in

       every case the callback using the format of the `nftw' version

       and get the correct result since the stack layout for a function

       call in C allows this.  */

    data.func = (NFTW_FUNC_T) func;

    /* Since we internally use the complete set of FTW_* values we need

       to reduce the value range before calling a `ftw' callback.  */

    data.cvt_arr = is_nftw ? nftw_arr : ftw_arr;

    /* No object known so far.  */

    data.known_objects = NULL;

    /* Now go to the directory containing the initial file/directory.  */

    if (flags & FTW_CHDIR)

    {

        /* GNU extension ahead.  */

        cwd =  getcwd (NULL, 0);

        if (cwd == NULL)

            result = -1;

        else if (data.ftw.base > 0)

        {

            /* Change to the directory the file is in.  In data.dirbuf

               we have a writable copy of the file name.  Just NUL

               terminate it for now and change the directory.  */

            if (data.ftw.base == 1)

                /* I.e., the file is in the root directory.  */

                result = chdir ("/");

            else

            {

                char ch = data.dirbuf[data.ftw.base - 1];

                data.dirbuf[data.ftw.base - 1] = '\0';

                result = chdir (data.dirbuf);

                data.dirbuf[data.ftw.base - 1] = ch;

            }

        }

    }

    /* Get stat info for start directory.  */

    if (result == 0)

    {

        const char *name = ((data.flags & FTW_CHDIR)

                ? data.dirbuf + data.ftw.base

                : data.dirbuf);

        if (((flags & FTW_PHYS)

                    ? LSTAT (name, &st)

                    : XSTAT (name, &st)) < 0)

        {

            if (!(flags & FTW_PHYS)

                    && errno == ENOENT

                    && LSTAT (name, &st) == 0

                    && S_ISLNK (st.st_mode))

                result = (*data.func) (data.dirbuf, &st, data.cvt_arr[FTW_SLN],

                        &data.ftw);

            else

                /* No need to call the callback since we cannot say anything

                   about the object.  */

                result = -1;

        }

        else

        {

            if (S_ISDIR (st.st_mode))

            {

                /* Remember the device of the initial directory in case

                   FTW_MOUNT is given.  */

                data.dev = st.st_dev;

                /* We know this directory now.  */

                if (!(flags & FTW_PHYS))

                    result = add_object (&data, &st);

                if (result == 0)

                    result = ftw_dir (&data, &st);

            }

            else

            {

                int flag = S_ISLNK (st.st_mode) ? FTW_SL : FTW_F;

                result = (*data.func) (data.dirbuf, &st, data.cvt_arr[flag],

                        &data.ftw);

            }

        }

    }

    /* Return to the start directory (if necessary).  */

    if (cwd != NULL)

    {

        int save_err = errno;

        chdir (cwd);

        free (cwd);

        __set_errno (save_err);

    }

    /* Free all memory.  */

    save_err = errno;

    tdestroy (data.known_objects, free);

    free (data.dirbuf);

    __set_errno (save_err);

    return result;

}

/* Entry points.  */

int FTW_NAME (const char *path, FTW_FUNC_T func, int descriptors)

{

    return ftw_startup (path, 0, func, descriptors, 0);

}

int NFTW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)

{

    return ftw_startup (path, 1, func, descriptors, flags);

}

#endif