open.c

Apache 2.0.63 is the current stable version of the 2.0 series, and is recommended over any previous

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "apr_private.h"
#include "apr_arch_file_io.h"
#include "apr_file_io.h"
#include "apr_general.h"
#include "apr_strings.h"
#include "apr_portable.h"
#include "apr_thread_mutex.h"
#if APR_HAVE_ERRNO_H
#include <errno.h>
#endif
#include <winbase.h>
#include <string.h>
#if APR_HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#include "apr_arch_misc.h"
#include "apr_arch_inherit.h"
#include <io.h>

#if APR_HAS_UNICODE_FS
apr_status_t utf8_to_unicode_path(apr_wchar_t* retstr, apr_size_t retlen, 
                                  const char* srcstr)
{
    /* TODO: The computations could preconvert the string to determine
     * the true size of the retstr, but that's a memory over speed
     * tradeoff that isn't appropriate this early in development.
     *
     * Allocate the maximum string length based on leading 4 
     * characters of \\?\ (allowing nearly unlimited path lengths) 
     * plus the trailing null, then transform /'s into \\'s since
     * the \\?\ form doesn't allow '/' path seperators.
     *
     * Note that the \\?\ form only works for local drive paths, and
     * \\?\UNC\ is needed UNC paths.
     */
    int srcremains = strlen(srcstr) + 1;
    apr_wchar_t *t = retstr;
    apr_status_t rv;

    /* This is correct, we don't twist the filename if it is will
     * definately be shorter than MAX_PATH.  It merits some 
     * performance testing to see if this has any effect, but there
     * seem to be applications that get confused by the resulting
     * Unicode \\?\ style file names, especially if they use argv[0]
     * or call the Win32 API functions such as GetModuleName, etc.
     * Not every application is prepared to handle such names.
     *
     * Note that a utf-8 name can never result in more wide chars
     * than the original number of utf-8 narrow chars.
     */
    if (srcremains > MAX_PATH) {
        if (srcstr[1] == ':' && (srcstr[2] == '/' || srcstr[2] == '\\')) {
            wcscpy (retstr, L"\\\\?\\");
            retlen -= 4;
            t += 4;
        }
        else if ((srcstr[0] == '/' || srcstr[0] == '\\')
              && (srcstr[1] == '/' || srcstr[1] == '\\')
              && (srcstr[2] != '?')) {
            /* Skip the slashes */
            srcstr += 2;
            srcremains -= 2;
            wcscpy (retstr, L"\\\\?\\UNC\\");
            retlen -= 8;
            t += 8;
        }
    }

    if (rv = apr_conv_utf8_to_ucs2(srcstr, &srcremains, t, &retlen)) {
        return (rv == APR_INCOMPLETE) ? APR_EINVAL : rv;
    }
    if (srcremains) {
        return APR_ENAMETOOLONG;
    }
    for (; *t; ++t)
        if (*t == L'/')
            *t = L'\\';
    return APR_SUCCESS;
}

apr_status_t unicode_to_utf8_path(char* retstr, apr_size_t retlen,
                                  const apr_wchar_t* srcstr)
{
    /* Skip the leading 4 characters if the path begins \\?\, or substitute
     * // for the \\?\UNC\ path prefix, allocating the maximum string
     * length based on the remaining string, plus the trailing null.
     * then transform \\'s back into /'s since the \\?\ form never
     * allows '/' path seperators, and APR always uses '/'s.
     */
    int srcremains = wcslen(srcstr) + 1;
    apr_status_t rv;
    char *t = retstr;
    if (srcstr[0] == L'\\' && srcstr[1] == L'\\' && 
        srcstr[2] == L'?'  && srcstr[3] == L'\\') {
        if (srcstr[4] == L'U' && srcstr[5] == L'N' && 
            srcstr[6] == L'C' && srcstr[7] == L'\\') {
            srcremains -= 8;
            srcstr += 8;
            retstr[0] = '\\';
            retstr[1] = '\\';
            retlen -= 2;
            t += 2;
        }
        else {
            srcremains -= 4;
            srcstr += 4;
        }
    }
        
    if (rv = apr_conv_ucs2_to_utf8(srcstr, &srcremains, t, &retlen)) {
        return rv;
    }
    if (srcremains) {
        return APR_ENAMETOOLONG;
    }
    return APR_SUCCESS;
}
#endif

void *res_name_from_filename(const char *file, int global, apr_pool_t *pool)
{
#if APR_HAS_UNICODE_FS
    IF_WIN_OS_IS_UNICODE
    {
        apr_wchar_t *wpre, *wfile, *ch;
        apr_size_t n = strlen(file) + 1;
        apr_size_t r, d;
        apr_status_t rv;

        if (apr_os_level >= APR_WIN_2000) {
            if (global)
                wpre = L"Global\\";
            else
                wpre = L"Local\\";
        }
        else
            wpre = L"";
        r = wcslen(wpre);

        if (n > 256 - r) {
            file += n - 256 - r;
            n = 256;
            /* skip utf8 continuation bytes */
            while ((*file & 0xC0) == 0x80) {
                ++file;
                --n;
            }
        }
        wfile = apr_palloc(pool, (r + n) * sizeof(apr_wchar_t));
        wcscpy(wfile, wpre);
        d = n;
        if (rv = apr_conv_utf8_to_ucs2(file, &n, wfile + r, &d)) {
            return NULL;
        }
        for (ch = wfile + r; *ch; ++ch) {
            if (*ch == ':' || *ch == '/' || *ch == '\\')
                *ch = '_';
        }
        return wfile;
    }
#endif
#if APR_HAS_ANSI_FS
    ELSE_WIN_OS_IS_ANSI
    {
        char *nfile, *ch;
        apr_size_t n = strlen(file) + 1;

#if !APR_HAS_UNICODE_FS
        apr_status_t rv;
        apr_size_t r, d;
        char *pre;

        if (apr_os_level >= APR_WIN_2000) {
            if (global)
                pre = "Global\\";
            else
                pre = "Local\\";
        }
        else
            pre = "";
        r = strlen(pre);

        if (n > 256 - r) {
            file += n - 256 - r;
            n = 256;
        }
        nfile = apr_palloc(pool, (r + n) * sizeof(apr_wchar_t));
        memcpy(nfile, pre, r);
        memcpy(nfile + r, file, n);
#else
        const apr_size_t r = 0;
        if (n > 256) {
            file += n - 256;
            n = 256;
        }
        nfile = apr_pmemdup(pool, file, n);
#endif
        for (ch = nfile + r; *ch; ++ch) {
            if (*ch == ':' || *ch == '/' || *ch == '\\')
                *ch = '_';
        }
        return nfile;
    }
#endif
}


apr_status_t file_cleanup(void *thefile)
{
    apr_file_t *file = thefile;
    apr_status_t flush_rv = APR_SUCCESS;

    if (file->filehand != INVALID_HANDLE_VALUE) {

        if (file->buffered) {
            /* XXX: flush here is not mutex protected */
            flush_rv = apr_file_flush((apr_file_t *)thefile);
        }

        /* In order to avoid later segfaults with handle 'reuse',
         * we must protect against the case that a dup2'ed handle
         * is being closed, and invalidate the corresponding StdHandle 
         * We also tell msvcrt when stdhandles are closed.
         */
        if (file->flags & APR_STD_FLAGS)
        {
            if ((file->flags & APR_STD_FLAGS) == APR_STDERR_FLAG) {
                _close(2);
                SetStdHandle(STD_ERROR_HANDLE, INVALID_HANDLE_VALUE);
            }
            else if ((file->flags & APR_STD_FLAGS) == APR_STDOUT_FLAG) {
                _close(1);
                SetStdHandle(STD_OUTPUT_HANDLE, INVALID_HANDLE_VALUE);
            }
            else if ((file->flags & APR_STD_FLAGS) == APR_STDIN_FLAG) {
                _close(0);
                SetStdHandle(STD_INPUT_HANDLE, INVALID_HANDLE_VALUE);
            }
        }
        else
            CloseHandle(file->filehand);

        file->filehand = INVALID_HANDLE_VALUE;
    }
    if (file->pOverlapped && file->pOverlapped->hEvent) {
        CloseHandle(file->pOverlapped->hEvent);
        file->pOverlapped = NULL;
    }
    return flush_rv;
}

APR_DECLARE(apr_status_t) apr_file_open(apr_file_t **new, const char *fname,
                                   apr_int32_t flag, apr_fileperms_t perm,
                                   apr_pool_t *pool)
{
    HANDLE handle = INVALID_HANDLE_VALUE;
    DWORD oflags = 0;
    DWORD createflags = 0;
    DWORD attributes = 0;
    DWORD sharemode = FILE_SHARE_READ | FILE_SHARE_WRITE;
    apr_status_t rv;

    if (flag & APR_READ) {
        oflags |= GENERIC_READ;
    }
    if (flag & APR_WRITE) {
        oflags |= GENERIC_WRITE;
    }
    if (flag & APR_WRITEATTRS) {
        oflags |= FILE_WRITE_ATTRIBUTES;
    }

    if (apr_os_level >= APR_WIN_NT) 
        sharemode |= FILE_SHARE_DELETE;

    if (flag & APR_CREATE) {
        if (flag & APR_EXCL) {
            /* only create new if file does not already exist */
            createflags = CREATE_NEW;
        } else if (flag & APR_TRUNCATE) {
            /* truncate existing file or create new */
            createflags = CREATE_ALWAYS;
        } else {
            /* open existing but create if necessary */
            createflags = OPEN_ALWAYS;
        }
    } else if (flag & APR_TRUNCATE) {
        /* only truncate if file already exists */
        createflags = TRUNCATE_EXISTING;
    } else {
        /* only open if file already exists */
        createflags = OPEN_EXISTING;
    }

    if ((flag & APR_EXCL) && !(flag & APR_CREATE)) {
        return APR_EACCES;
    }