Fix bug #8541 - readlink() on Linux clients fails if the symlink target is outside...

[Samba.git] / source3 / modules / charset_macosxfs.c

/* 
   Unix SMB/CIFS implementation.
   Samba charset module for Mac OS X/Darwin
   Copyright (C) Benjamin Riefenstahl 2003
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
 * modules/charset_macosxfs.c
 *
 * A Samba charset module to use on Mac OS X/Darwin as the filesystem
 * and display encoding.
 *
 * Actually two implementations are provided here.  The default
 * implementation is based on the official CFString API.  The other is
 * based on internal CFString APIs as defined in the OpenDarwin
 * source.
 */

#include "includes.h"

/*
 * Include OS frameworks.  These are only needed in this module.
 */
#include <CoreFoundation/CFString.h>

/*
 * See if autoconf has found us the internal headers in some form.
 */
#if HAVE_COREFOUNDATION_CFSTRINGENCODINGCONVERTER_H
#       include <CoreFoundation/CFStringEncodingConverter.h>
#       include <CoreFoundation/CFUnicodePrecomposition.h>
#       define USE_INTERNAL_API 1
#elif HAVE_CFSTRINGENCODINGCONVERTER_H
#       include <CFStringEncodingConverter.h>
#       include <CFUnicodePrecomposition.h>
#       define USE_INTERNAL_API 1
#endif

/*
 * Compile time configuration: Do we want debug output?
 */
/* #define DEBUG_STRINGS 1 */

/*
 * A simple, but efficient memory provider for our buffers.
 */
static inline void *resize_buffer (void *buffer, size_t *size, size_t newsize)
{
        if (newsize > *size) {
                *size = newsize + 128;
                buffer = SMB_REALLOC(buffer, *size);
        }
        return buffer;
}

/*
 * While there is a version of OpenDarwin for intel, the usual case is
 * big-endian PPC.  So we need byte swapping to handle the
 * little-endian byte order of the network protocol.  We also need an
 * additional dynamic buffer to do this work for incoming data blocks,
 * because we have to consider the original data as constant.
 *
 * We abstract the differences away by providing a simple facade with
 * these functions/macros:
 *
 *      le_to_native(dst,src,len)
 *      native_to_le(cp,len)
 *      set_ucbuffer_with_le(buffer,bufsize,data,size)
 *      set_ucbuffer_with_le_copy(buffer,bufsize,data,size,reserve)
 */
#ifdef WORDS_BIGENDIAN

static inline void swap_bytes (char * dst, const char * src, size_t len)
{
        const char *srcend = src + len;
        while (src < srcend) {
                dst[0] = src[1];
                dst[1] = src[0];
                dst += 2;
                src += 2;
        }
}
static inline void swap_bytes_inplace (char * cp, size_t len)
{
        char temp;
        char *end = cp + len;
        while (cp  < end) {
                temp = cp[1];
                cp[1] = cp[0];
                cp[0] = temp;
                cp += 2;
        }
}

#define le_to_native(dst,src,len)       swap_bytes(dst,src,len)
#define native_to_le(cp,len)            swap_bytes_inplace(cp,len)
#define set_ucbuffer_with_le(buffer,bufsize,data,size) \
        set_ucbuffer_with_le_copy(buffer,bufsize,data,size,0)

#else   /* ! WORDS_BIGENDIAN */

#define le_to_native(dst,src,len)       memcpy(dst,src,len)
#define native_to_le(cp,len)            /* nothing */
#define set_ucbuffer_with_le(buffer,bufsize,data,size) \
        (((void)(bufsize)),(UniChar*)(data))

#endif

static inline UniChar *set_ucbuffer_with_le_copy (
        UniChar *buffer, size_t *bufsize,
        const void *data, size_t size, size_t reserve)
{
        buffer = resize_buffer(buffer, bufsize, size+reserve);
        le_to_native((char*)buffer,data,size);
        return buffer;
}


/*
 * A simple hexdump function for debugging error conditions.
 */
#define debug_out(s)    DEBUG(0,(s))

#ifdef DEBUG_STRINGS

static void hexdump( const char * label, const char * s, size_t len )
{
        size_t restlen = len;
        debug_out("<<<<<<<\n");
        debug_out(label);
        debug_out("\n");
        while (restlen > 0) {
                char line[100];
                size_t i, j;
                char * d = line;
#undef sprintf
                d += sprintf(d, "%04X ", (unsigned)(len-restlen));
                *d++ = ' ';
                for( i = 0; i<restlen && i<8; ++i ) {
                        d += sprintf(d, "%02X ", ((unsigned)s[i]) & 0xFF);
                }
                for( j = i; j<8; ++j ) {
                        d += sprintf(d, "   ");
                }
                *d++ = ' ';
                for( i = 8; i<restlen && i<16; ++i ) {
                        d += sprintf(d, "%02X ", ((unsigned)s[i]) & 0xFF);
                }
                for( j = i; j<16; ++j ) {
                        d += sprintf(d, "   ");
                }
                *d++ = ' ';
                for( i = 0; i<restlen && i<16; ++i ) {
                        if(s[i] < ' ' || s[i] >= 0x7F || !isprint(s[i]))
                                *d++ = '.';
                        else
                                *d++ = s[i];
                }
                *d++ = '\n';
                *d = 0;
                restlen -= i;
                s += i;
                debug_out(line);
        }
        debug_out(">>>>>>>\n");
}

#else   /* !DEBUG_STRINGS */

#define hexdump(label,s,len) /* nothing */

#endif


#if !USE_INTERNAL_API

/*
 * An implementation based on documented Mac OS X APIs.
 *
 * This does a certain amount of memory management, creating and
 * manipulating CFString objects.  We try to minimize the impact by
 * keeping those objects around and re-using them.  We also use
 * external backing store for the CFStrings where this is possible and
 * benficial.
 *
 * The Unicode normalizations forms available at this level are
 * generic, not specifically for the file system.  So they may not be
 * perfect fits.
 */
static size_t macosxfs_encoding_pull(
        void *cd,                               /* Encoder handle */
        char **inbuf, size_t *inbytesleft,      /* Script string */
        char **outbuf, size_t *outbytesleft)    /* UTF-16-LE string */
{
        static const int script_code = kCFStringEncodingUTF8;
        static CFMutableStringRef cfstring = NULL;
        size_t outsize;
        CFRange range;

        (void) cd; /* UNUSED */

        if (0 == *inbytesleft) {
                return 0;
        }

        if (NULL == cfstring) {
                /*
                 * A version with an external backing store as in the
                 * push function should have been more efficient, but
                 * testing shows, that it is actually slower (!).
                 * Maybe kCFAllocatorDefault gets shortcut evaluation
                 * internally, while kCFAllocatorNull doesn't.
                 */
                cfstring = CFStringCreateMutable(kCFAllocatorDefault,0);
        }

        /*
         * Three methods of appending to a CFString, choose the most
         * efficient.
         */
        if (0 == (*inbuf)[*inbytesleft-1]) {
                CFStringAppendCString(cfstring, *inbuf, script_code);
        } else if (*inbytesleft <= 255) {
                Str255 buffer;
                buffer[0] = *inbytesleft;
                memcpy(buffer+1, *inbuf, buffer[0]);
                CFStringAppendPascalString(cfstring, buffer, script_code);
        } else {
                /*
                 * We would like to use a fixed buffer and a loop
                 * here, but than we can't garantee that the input is
                 * well-formed UTF-8, as we are supposed to do.
                 */
                static char *buffer = NULL;
                static size_t buflen = 0;
                buffer = resize_buffer(buffer, &buflen, *inbytesleft+1);
                memcpy(buffer, *inbuf, *inbytesleft);
                buffer[*inbytesleft] = 0;
                CFStringAppendCString(cfstring, *inbuf, script_code);
        }

        /*
         * Compose characters, using the non-canonical composition
         * form.
         */
        CFStringNormalize(cfstring, kCFStringNormalizationFormC);

        outsize = CFStringGetLength(cfstring);
        range = CFRangeMake(0,outsize);

        if (outsize == 0) {
                /*
                 * HACK: smbd/mangle_hash2.c:is_legal_name() expects
                 * errors here.  That function will always pass 2
                 * characters.  smbd/open.c:check_for_pipe() cuts a
                 * patchname to 10 characters blindly.  Suppress the
                 * debug output in those cases.
                 */
                if(2 != *inbytesleft && 10 != *inbytesleft) {
                        debug_out("String conversion: "
                                  "An unknown error occurred\n");
                        hexdump("UTF8->UTF16LE (old) input",
                                *inbuf, *inbytesleft);
                }
                errno = EILSEQ; /* Not sure, but this is what we have
                                 * actually seen. */
                return -1;
        }
        if (outsize*2 > *outbytesleft) {
                CFStringDelete(cfstring, range);
                debug_out("String conversion: "
                          "Output buffer too small\n");
                hexdump("UTF8->UTF16LE (old) input",
                        *inbuf, *inbytesleft);
                errno = E2BIG;
                return -1;
        }

        CFStringGetCharacters(cfstring, range, (UniChar*)*outbuf);
        CFStringDelete(cfstring, range);

        native_to_le(*outbuf, outsize*2);

        /*
         * Add a converted null byte, if the CFString conversions
         * prevented that until now.
         */
        if (0 == (*inbuf)[*inbytesleft-1] && 
            (0 != (*outbuf)[outsize*2-1] || 0 != (*outbuf)[outsize*2-2])) {

                if ((outsize*2+2) > *outbytesleft) {
                        debug_out("String conversion: "
                                  "Output buffer too small\n");
                        hexdump("UTF8->UTF16LE (old) input",
                                *inbuf, *inbytesleft);
                        errno = E2BIG;
                        return -1;
                }

                (*outbuf)[outsize*2] = (*outbuf)[outsize*2+1] = 0;
                outsize += 2;
        }

        *inbuf += *inbytesleft;
        *inbytesleft = 0;
        *outbuf += outsize*2;
        *outbytesleft -= outsize*2;

        return 0;
}

static size_t macosxfs_encoding_push(
        void *cd,                               /* Encoder handle */
        char **inbuf, size_t *inbytesleft,      /* UTF-16-LE string */
        char **outbuf, size_t *outbytesleft)    /* Script string */
{
        static const int script_code = kCFStringEncodingUTF8;
        static CFMutableStringRef cfstring = NULL;
        static UniChar *buffer = NULL;
        static size_t buflen = 0;
        CFIndex outsize, cfsize, charsconverted;

        (void) cd; /* UNUSED */

        if (0 == *inbytesleft) {
                return 0;
        }

        /*
         * We need a buffer that can hold 4 times the original data,
         * because that is the theoretical maximum that decomposition
         * can create currently (in Unicode 4.0).
         */
        buffer = set_ucbuffer_with_le_copy(
                buffer, &buflen, *inbuf, *inbytesleft, 3 * *inbytesleft);

        if (NULL == cfstring) {
                cfstring = CFStringCreateMutableWithExternalCharactersNoCopy(
                        kCFAllocatorDefault,
                        buffer, *inbytesleft/2, buflen/2,
                        kCFAllocatorNull);
        } else {
                CFStringSetExternalCharactersNoCopy(
                        cfstring,
                        buffer, *inbytesleft/2, buflen/2);
        }

        /*
         * Decompose characters, using the non-canonical decomposition
         * form.
         *
         * NB: This isn't exactly what HFS+ wants (see note on
         * kCFStringEncodingUseHFSPlusCanonical in
         * CFStringEncodingConverter.h), but AFAIK it's the best that
         * the official API can do.
         */
        CFStringNormalize(cfstring, kCFStringNormalizationFormD);

        cfsize = CFStringGetLength(cfstring);
        charsconverted = CFStringGetBytes(
                cfstring, CFRangeMake(0,cfsize),
                script_code, 0, False,
                *outbuf, *outbytesleft, &outsize);

        if (0 == charsconverted) {
                debug_out("String conversion: "
                          "Buffer too small or not convertable\n");
                hexdump("UTF16LE->UTF8 (old) input",
                        *inbuf, *inbytesleft);
                errno = EILSEQ; /* Probably more likely. */
                return -1;
        }

        /*
         * Add a converted null byte, if the CFString conversions
         * prevented that until now.
         */
        if (0 == (*inbuf)[*inbytesleft-1] && 0 == (*inbuf)[*inbytesleft-2] &&
            (0 != (*outbuf)[outsize-1])) {

                if (((size_t)outsize+1) > *outbytesleft) {
                        debug_out("String conversion: "
                                  "Output buffer too small\n");
                        hexdump("UTF16LE->UTF8 (old) input",
                                *inbuf, *inbytesleft);
                        errno = E2BIG;
                        return -1;
                }

                (*outbuf)[outsize] = 0;
                ++outsize;
        }

        *inbuf += *inbytesleft;
        *inbytesleft = 0;
        *outbuf += outsize;
        *outbytesleft -= outsize;

        return 0;
}

#else /* USE_INTERNAL_API */

/*
 * An implementation based on internal code as known from the
 * OpenDarwin CVS.
 *
 * This code doesn't need much memory management because it uses
 * functions that operate on the raw memory directly.
 *
 * The push routine here is faster and more compatible with HFS+ than
 * the other implementation above.  The pull routine is only faster
 * for some strings, slightly slower for others.  The pull routine
 * looses because it has to iterate over the data twice, once to
 * decode UTF-8 and than to do the character composition required by
 * Windows.
 */
static size_t macosxfs_encoding_pull(
        void *cd,                               /* Encoder handle */
        char **inbuf, size_t *inbytesleft,      /* Script string */
        char **outbuf, size_t *outbytesleft)    /* UTF-16-LE string */
{
        static const int script_code = kCFStringEncodingUTF8;
        UInt32 srcCharsUsed = 0;
        UInt32 dstCharsUsed = 0;
        UInt32 result;
        uint32_t dstDecomposedUsed = 0;
        uint32_t dstPrecomposedUsed = 0;

        (void) cd; /* UNUSED */

        if (0 == *inbytesleft) {
                return 0;
        }

        result = CFStringEncodingBytesToUnicode(
                script_code, kCFStringEncodingComposeCombinings,
                *inbuf, *inbytesleft, &srcCharsUsed,
                (UniChar*)*outbuf, *outbytesleft, &dstCharsUsed);

        switch(result) {
        case kCFStringEncodingConversionSuccess:
                if (*inbytesleft == srcCharsUsed)
                        break;
                else
                        ; /*fall through*/
        case kCFStringEncodingInsufficientOutputBufferLength:
                debug_out("String conversion: "
                          "Output buffer too small\n");
                hexdump("UTF8->UTF16LE (new) input",
                        *inbuf, *inbytesleft);
                errno = E2BIG;
                return -1;
        case kCFStringEncodingInvalidInputStream:
                /*
                 * HACK: smbd/mangle_hash2.c:is_legal_name() expects
                 * errors here.  That function will always pass 2
                 * characters.  smbd/open.c:check_for_pipe() cuts a
                 * patchname to 10 characters blindly.  Suppress the
                 * debug output in those cases.
                 */
                if(2 != *inbytesleft && 10 != *inbytesleft) {
                        debug_out("String conversion: "
                                  "Invalid input sequence\n");
                        hexdump("UTF8->UTF16LE (new) input",
                                *inbuf, *inbytesleft);
                }
                errno = EILSEQ;
                return -1;
        case kCFStringEncodingConverterUnavailable:
                debug_out("String conversion: "
                          "Unknown encoding\n");
                hexdump("UTF8->UTF16LE (new) input",
                        *inbuf, *inbytesleft);
                errno = EINVAL;
                return -1;
        }

        /*
         * It doesn't look like CFStringEncodingBytesToUnicode() can
         * produce precomposed characters (flags=ComposeCombinings
         * doesn't do it), so we need another pass over the data here.
         * We can do this in-place, as the string can only get
         * shorter.
         *
         * (Actually in theory there should be an internal
         * decomposition and reordering before the actual composition
         * step.  But we should be able to rely on that we always get
         * fully decomposed strings for input, so this can't create
         * problems in reality.)
         */
        CFUniCharPrecompose(
                (const UTF16Char *)*outbuf, dstCharsUsed, &dstDecomposedUsed,
                (UTF16Char *)*outbuf, dstCharsUsed, &dstPrecomposedUsed);

        native_to_le(*outbuf, dstPrecomposedUsed*2);

        *inbuf += srcCharsUsed;
        *inbytesleft -= srcCharsUsed;
        *outbuf += dstPrecomposedUsed*2;
        *outbytesleft -= dstPrecomposedUsed*2;

        return 0;
}

static size_t macosxfs_encoding_push(
        void *cd,                               /* Encoder handle */
        char **inbuf, size_t *inbytesleft,      /* UTF-16-LE string */
        char **outbuf, size_t *outbytesleft)    /* Script string */
{
        static const int script_code = kCFStringEncodingUTF8;
        static UniChar *buffer = NULL;
        static size_t buflen = 0;
        UInt32 srcCharsUsed=0, dstCharsUsed=0, result;

        (void) cd; /* UNUSED */

        if (0 == *inbytesleft) {
                return 0;
        }

        buffer = set_ucbuffer_with_le(
                buffer, &buflen, *inbuf, *inbytesleft);

        result = CFStringEncodingUnicodeToBytes(
                script_code, kCFStringEncodingUseHFSPlusCanonical,
                buffer, *inbytesleft/2, &srcCharsUsed,
                *outbuf, *outbytesleft, &dstCharsUsed);

        switch(result) {
        case kCFStringEncodingConversionSuccess:
                if (*inbytesleft/2 == srcCharsUsed)
                        break;
                else
                        ; /*fall through*/
        case kCFStringEncodingInsufficientOutputBufferLength:
                debug_out("String conversion: "
                          "Output buffer too small\n");
                hexdump("UTF16LE->UTF8 (new) input",
                        *inbuf, *inbytesleft);
                errno = E2BIG;
                return -1;
        case kCFStringEncodingInvalidInputStream:
                /*
                 * HACK: smbd/open.c:check_for_pipe():is_legal_name()
                 * cuts a pathname to 10 characters blindly.  Suppress
                 * the debug output in those cases.
                 */
                if(10 != *inbytesleft) {
                        debug_out("String conversion: "
                                  "Invalid input sequence\n");
                        hexdump("UTF16LE->UTF8 (new) input",
                                *inbuf, *inbytesleft);
                }
                errno = EILSEQ;
                return -1;
        case kCFStringEncodingConverterUnavailable:
                debug_out("String conversion: "
                          "Unknown encoding\n");
                hexdump("UTF16LE->UTF8 (new) input",
                        *inbuf, *inbytesleft);
                errno = EINVAL;
                return -1;
        }

        *inbuf += srcCharsUsed*2;
        *inbytesleft -= srcCharsUsed*2;
        *outbuf += dstCharsUsed;
        *outbytesleft -= dstCharsUsed;

        return 0;
}

#endif /* USE_INTERNAL_API */

/*
 * For initialization, actually install the encoding as "macosxfs".
 */
static struct charset_functions macosxfs_encoding_functions = {
        "MACOSXFS", macosxfs_encoding_pull, macosxfs_encoding_push
};

NTSTATUS charset_macosxfs_init(void)
{
        if (!smb_register_charset(&macosxfs_encoding_functions)) {
                return NT_STATUS_INTERNAL_ERROR;
        }
        return NT_STATUS_OK;
}

/* eof */