vfs_shadow_copy2: Use VFS interface to derive mount point

[samba4-gss.git] / lib / util / charset / convert_string.c

/*
   Unix SMB/CIFS implementation.
   Character set conversion Extensions
   Copyright (C) Igor Vergeichik <iverg@mail.ru> 2001
   Copyright (C) Andrew Tridgell 2001-2011
   Copyright (C) Andrew Bartlett 2011
   Copyright (C) Simo Sorce 2001
   Copyright (C) Martin Pool 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/>.

*/
#include "replace.h"
#include "system/iconv.h"
#include "charset.h"
#include "lib/util/debug.h"
#include "lib/util/fault.h"

/**
 * @file
 *
 * @brief Character-set conversion routines built on our iconv.
 *
 * @note Samba's internal character set (at least in the 3.0 series)
 * is always the same as the one for the Unix filesystem.  It is
 * <b>not</b> necessarily UTF-8 and may be different on machines that
 * need i18n filenames to be compatible with Unix software.  It does
 * have to be a superset of ASCII.  All multibyte sequences must start
 * with a byte with the high bit set.
 *
 * @sa lib/iconv.c
 */


/**
 * Convert string from one encoding to another, making error checking etc
 * Slow path version - uses (slow) iconv.
 *
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string
 * @param converted size is the number of bytes occupied in the destination
 *
 * @returns false and sets errno on fail, true on success.
 *
 * Ensure the srclen contains the terminating zero.
 *
 **/

static bool convert_string_internal(struct smb_iconv_handle *ic,
                                    charset_t from, charset_t to,
                                    void const *src, size_t srclen,
                                    void *dest, size_t destlen, size_t *converted_size)
{
        size_t i_len, o_len;
        size_t retval;
        const char* inbuf = (const char*)src;
        char* outbuf = (char*)dest;
        smb_iconv_t descriptor;

        descriptor = get_conv_handle(ic, from, to);

        if (srclen == (size_t)-1) {
                if (from == CH_UTF16LE || from == CH_UTF16BE) {
                        srclen = (strlen_w((const smb_ucs2_t *)src)+1) * 2;
                } else {
                        srclen = strlen((const char *)src)+1;
                }
        }


        if (descriptor == (smb_iconv_t)-1 || descriptor == (smb_iconv_t)0) {
                errno = EINVAL;
                return false;
        }

        i_len=srclen;
        o_len=destlen;

        retval = smb_iconv(descriptor, &inbuf, &i_len, &outbuf, &o_len);
        *converted_size = destlen-o_len;

        return (retval != (size_t)-1);
}

/**
 * Convert string from one encoding to another, making error checking etc
 * Fast path version - handles ASCII first.
 *
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes, or -1 for nul terminated.
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string - *NEVER* -1.
 * @param converted size is the number of bytes occupied in the destination
 *
 * @returns false and sets errno on fail, true on success.
 *
 * Ensure the srclen contains the terminating zero.
 *
 * This function has been hand-tuned to provide a fast path.
 * Don't change unless you really know what you are doing. JRA.
 **/

bool convert_string_error_handle(struct smb_iconv_handle *ic,
                                 charset_t from, charset_t to,
                                 void const *src, size_t srclen,
                                 void *dest, size_t destlen,
                                 size_t *converted_size)
{
        /*
         * NB. We deliberately don't do a strlen here if srclen == -1.
         * This is very expensive over millions of calls and is taken
         * care of in the slow path in convert_string_internal. JRA.
         */

#ifdef DEVELOPER
        SMB_ASSERT(destlen != (size_t)-1);
#endif

        if (srclen == 0) {
                *converted_size = 0;
                return true;
        }

        if (from != CH_UTF16LE && from != CH_UTF16BE && to != CH_UTF16LE && to != CH_UTF16BE) {
                const unsigned char *p = (const unsigned char *)src;
                unsigned char *q = (unsigned char *)dest;
                size_t slen = srclen;
                size_t dlen = destlen;
                unsigned char lastp = '\0';
                size_t retval = 0;

                /* If all characters are ascii, fast path here. */
                while (slen && dlen) {
                        if ((lastp = *p) <= 0x7f) {
                                *q++ = *p++;
                                if (slen != (size_t)-1) {
                                        slen--;
                                }
                                dlen--;
                                retval++;
                                if (!lastp)
                                        break;
                        } else {
#ifdef BROKEN_UNICODE_COMPOSE_CHARACTERS
                                goto general_case;
#else
                                bool ret = convert_string_internal(ic, from, to, p, slen, q, dlen, converted_size);
                                *converted_size += retval;
                                return ret;
#endif
                        }
                }

                *converted_size = retval;

                if (!dlen) {
                        /* Even if we fast path we should note if we ran out of room. */
                        if (((slen != (size_t)-1) && slen) ||
                                        ((slen == (size_t)-1) && lastp)) {
                                errno = E2BIG;
                                return false;
                        }
                }
                return true;
        } else if (from == CH_UTF16LE && to != CH_UTF16LE) {
                const unsigned char *p = (const unsigned char *)src;
                unsigned char *q = (unsigned char *)dest;
                size_t retval = 0;
                size_t slen = srclen;
                size_t dlen = destlen;
                unsigned char lastp = '\0';
#ifndef BROKEN_UNICODE_COMPOSE_CHARACTERS
                bool ret;
#endif

                if (slen == (size_t)-1) {
                        while (dlen &&
                               ((lastp = *p) <= 0x7f) && (p[1] == 0)) {
                                *q++ = *p;
                                p += 2;
                                dlen--;
                                retval++;
                                if (!lastp)
                                        break;
                        }
                        if (lastp != 0) goto slow_path;
                } else {
                        while (slen >= 2 && dlen &&
                               (*p <= 0x7f) && (p[1] == 0)) {
                                *q++ = *p;
                                slen -= 2;
                                p += 2;
                                dlen--;
                                retval++;
                        }
                        if (slen != 0) goto slow_path;
                }

                *converted_size = retval;
                return true;

        slow_path:
                /* come here when we hit a character we can't deal
                 * with in the fast path
                 */
#ifdef BROKEN_UNICODE_COMPOSE_CHARACTERS
                goto general_case;
#else
                ret = convert_string_internal(ic, from, to, p, slen, q, dlen, converted_size);
                *converted_size += retval;
                return ret;
#endif

        } else if (from != CH_UTF16LE && from != CH_UTF16BE && to == CH_UTF16LE) {
                const unsigned char *p = (const unsigned char *)src;
                unsigned char *q = (unsigned char *)dest;
                size_t retval = 0;
                size_t slen = srclen;
                size_t dlen = destlen;
                unsigned char lastp = '\0';

                /* If all characters are ascii, fast path here. */
                while (slen && (dlen >= 1)) {
                        if (dlen >=2 && (lastp = *p) <= 0x7F) {
                                *q++ = *p++;
                                *q++ = '\0';
                                if (slen != (size_t)-1) {
                                        slen--;
                                }
                                dlen -= 2;
                                retval += 2;
                                if (!lastp)
                                        break;
                        } else {
#ifdef BROKEN_UNICODE_COMPOSE_CHARACTERS
                                goto general_case;
#else
                                bool ret = convert_string_internal(ic, from, to, p, slen, q, dlen, converted_size);
                                *converted_size += retval;
                                return ret;
#endif
                        }
                }

                *converted_size = retval;

                if (!dlen) {
                        /* Even if we fast path we should note if we ran out of room. */
                        if (((slen != (size_t)-1) && slen) ||
                                        ((slen == (size_t)-1) && lastp)) {
                                errno = E2BIG;
                                return false;
                        }
                }
                return true;
        }

#ifdef BROKEN_UNICODE_COMPOSE_CHARACTERS
  general_case:
#endif
        return convert_string_internal(ic, from, to, src, srclen, dest, destlen, converted_size);
}

bool convert_string_handle(struct smb_iconv_handle *ic,
                           charset_t from, charset_t to,
                           void const *src, size_t srclen,
                           void *dest, size_t destlen,
                           size_t *converted_size)
{
        bool ret = convert_string_error_handle(ic, from, to, src, srclen, dest, destlen, converted_size);

        if(ret==false) {
                const char *reason="unknown error";
                switch(errno) {
                        case EINVAL:
                                reason="Incomplete multibyte sequence";
                                DBG_NOTICE("Conversion error: %s\n",
                                         reason);
                                break;
                        case E2BIG:
                        {
                                reason="No more room";
                                if (from == CH_UNIX) {
                                        DBG_NOTICE("E2BIG: convert_string(%s,%s): srclen=%u destlen=%u error: %s\n",
                                                   charset_name(ic, from), charset_name(ic, to),
                                                   (unsigned int)srclen, (unsigned int)destlen, reason);
                                } else {
                                        DBG_NOTICE("E2BIG: convert_string(%s,%s): srclen=%u destlen=%u error: %s\n",
                                                   charset_name(ic, from), charset_name(ic, to),
                                                   (unsigned int)srclen, (unsigned int)destlen, reason);
                                }
                                break;
                        }
                        case EILSEQ:
                                reason="Illegal multibyte sequence";
                                DBG_NOTICE("convert_string_internal: Conversion error: %s\n",
                                           reason);
                                break;
                        default:
                                DBG_ERR("convert_string_internal: Conversion error: %s\n",
                                        reason);
                                break;
                }
                /* smb_panic(reason); */
        }
        return ret;
}


/**
 * Convert between character sets, allocating a new buffer using talloc for the result.
 *
 * @param srclen length of source buffer.
 * @param dest always set at least to NULL
 * @param converted_size set to the number of bytes occupied by the string in
 * the destination on success.
 * @note -1 is not accepted for srclen.
 *
 * @return true if new buffer was correctly allocated, and string was
 * converted.
 *
 * Ensure the srclen contains the terminating zero.
 */
bool convert_string_talloc_handle(TALLOC_CTX *ctx, struct smb_iconv_handle *ic,
                                  charset_t from, charset_t to,
                                  void const *src, size_t srclen, void *dst,
                                  size_t *converted_size)

{
        size_t i_len, o_len, destlen;
        size_t retval;
        const char *inbuf = NULL;
        char *outbuf = NULL, *ob = NULL;
        smb_iconv_t descriptor;
        void **dest = dst;

        *dest = NULL;
        if (converted_size != NULL) {
                *converted_size = 0;
        }

        if (src == NULL || srclen == (size_t)-1) {
                errno = EINVAL;
                return false;
        }

        if (srclen == 0) {
                /* We really should treat this as an error, but
                   there are too many callers that need this to
                   return a NULL terminated string in the correct
                   character set. */
                if (to == CH_UTF16LE|| to == CH_UTF16BE || to == CH_UTF16MUNGED) {
                        destlen = 2;
                } else {
                        destlen = 1;
                }
                ob = talloc_zero_array(ctx, char, destlen);
                if (ob == NULL) {
                        DBG_ERR("Could not talloc destination buffer.\n");
                        errno = ENOMEM;
                        return false;
                }
                if (converted_size != NULL) {
                        *converted_size = destlen;
                }
                *dest = ob;
                return true;
        }

        descriptor = get_conv_handle(ic, from, to);

        if (descriptor == (smb_iconv_t)-1 || descriptor == (smb_iconv_t)0) {
                DEBUG(0,("convert_string_talloc: Conversion not supported.\n"));
                errno = EOPNOTSUPP;
                return false;
        }

        if (srclen >= (SIZE_MAX - 2) / 3) {
                DBG_ERR("convert_string_talloc: "
                        "srclen is %zu, destlen would wrap!\n",
                        srclen);
                errno = EOPNOTSUPP;
                return false;
        }
        destlen = srclen * 3;

        /* +2 is for ucs2 null termination. */
        ob = talloc_realloc(ctx, ob, char, destlen + 2);

        if (!ob) {
                DEBUG(0, ("convert_string_talloc: realloc failed!\n"));
                errno = ENOMEM;
                return false;
        }
        outbuf = ob;
        i_len = srclen;
        o_len = destlen;
        inbuf = (const char *)src;

        retval = smb_iconv(descriptor,
                           &inbuf, &i_len,
                           &outbuf, &o_len);
        if(retval == (size_t)-1)                {
                const char *reason="unknown error";
                switch(errno) {
                        case EINVAL:
                                reason="Incomplete multibyte sequence";
                                DBG_NOTICE("Conversion error: %s\n",
                                           reason);
                                break;
                        case E2BIG:
                                reason = "output buffer is too small";
                                DBG_ERR("Conversion error: %s\n",
                                        reason);
                                break;
                        case EILSEQ:
                                reason="Illegal multibyte sequence";
                                DBG_NOTICE("Conversion error: %s\n",
                                           reason);
                                break;
                        default:
                                DBG_ERR("Conversion error: %s\n",
                                        reason);
                                break;
                }
                /* smb_panic(reason); */
                TALLOC_FREE(ob);
                return false;
        }

        destlen = destlen - o_len;
        /* Don't shrink unless we're reclaiming a lot of
         * space. This is in the hot codepath and these
         * reallocs *cost*. JRA.
         */
        if (o_len > 1024) {
                /* We're shrinking here so we know the +2 is safe from wrap. */
                ob = talloc_realloc(ctx,ob, char, destlen + 2);
        }

        if (destlen && !ob) {
                DEBUG(0, ("convert_string_talloc: out of memory!\n"));
                errno = ENOMEM;
                return false;
        }

        *dest = ob;

        /* Must ucs2 null terminate in the extra space we allocated. */
        ob[destlen] = '\0';
        ob[destlen+1] = '\0';

        /* Ensure we can never return a *converted_size of zero. */
        if (destlen == 0) {
                /* As we're now returning false on a bad smb_iconv call,
                   this should never happen. But be safe anyway. */
                if (to == CH_UTF16LE|| to == CH_UTF16BE || to == CH_UTF16MUNGED) {
                        destlen = 2;
                } else {
                        destlen = 1;
                }
        }

        if (converted_size != NULL) {
                *converted_size = destlen;
        }
        return true;
}

/**
 * Convert string from one encoding to another, with error checking.
 * This version produces more logging information than
 * convert_string_error(), but is otherwise functionally identical.
 *
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string
 * @param converted_size the number of bytes occupied in the destination
 *
 * @returns true on success, false on fail.
 **/
_PUBLIC_ bool convert_string(charset_t from, charset_t to,
                               void const *src, size_t srclen,
                               void *dest, size_t destlen,
                               size_t *converted_size)
{
        return convert_string_handle(get_iconv_handle(), from, to,
                                        src, srclen,
                                        dest, destlen, converted_size);
}

/**
 * Convert string from one encoding to another, with error checking.
 * This version is less verbose than convert_string().
 *
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string
 * @param converted_size the number of bytes occupied in the destination
 *
 * @returns true on success, false on fail.
 **/
_PUBLIC_ bool convert_string_error(charset_t from, charset_t to,
                                   void const *src, size_t srclen,
                                   void *dest, size_t destlen,
                                   size_t *converted_size)
{
        return convert_string_error_handle(get_iconv_handle(), from, to,
                                           src, srclen,
                                           dest, destlen, converted_size);
}

/**
 * Convert between character sets, allocating a new buffer using talloc for the result.
 *
 * @param srclen length of source buffer.
 * @param dest always set at least to NULL
 * @param converted_size Size in bytes of the converted string
 * @note -1 is not accepted for srclen.
 *
 * @returns boolean indication whether the conversion succeeded
 **/

_PUBLIC_ bool convert_string_talloc(TALLOC_CTX *ctx,
                                    charset_t from, charset_t to,
                                    void const *src, size_t srclen,
                                    void *dest, size_t *converted_size)
{
        return convert_string_talloc_handle(ctx, get_iconv_handle(),
                                                 from, to, src, srclen, dest,
                                                 converted_size);
}