Fossil

    }else{
      z[--j] = z[i];
    }
  }
}

/*
** pBlob is a shell command under construction.  This routine safely
** appends argument zIn.
**
** The argument is escaped if it contains white space or other characters
** that need to be escaped for the shell.  If zIn contains characters
** that cannot be safely escaped, then throw a fatal error.
**
** The argument is expected to a filename of some kinds.  As shell commands
** commonly have command-line options that begin with "-" and since we
** do not want an attacker to be able to invoke these switches using
** filenames that begin with "-", if zIn begins with "-", prepend
** an additional "./".
*/
void blob_append_escaped_arg(Blob *pBlob, const char *zIn){
  int i;
  char c;
  int needEscape = 0;
  int n = blob_size(pBlob);
  char *z = blob_buffer(pBlob);
#if defined(_WIN32_)
  const char cQuote = '"';    /* Use "..." quoting on windows */
#else
  const char cQuote = '\'';   /* Use '...' quoting on unix */
#endif

  for(i=0; (c = zIn[i])!=0; i++){
    if( c==cQuote || c=='\\' || c<' ' ) {
      Blob bad;
      blob_token(pBlob, &bad);
      fossil_fatal("the [%s] argument to the \"%s\" command contains "
                   "a character (ascii 0x%02x) that is a security risk",
                   zIn, blob_str(&bad), c);

      if( !needEscape && !fossil_isspace(c) && c!='/' && c!='.' && c!='_' ){
        needEscape = 1;
      }

    }
  }
  if( n>0 && !fossil_isspace(z[n-1]) ){
    blob_append(pBlob, " ", 1);
  }
  if( needEscape ) blob_append(pBlob, &cQuote, 1);
  if( zIn[0]=='-' ) blob_append(pBlob, "./", 2);
  blob_append(pBlob, zIn, -1);
  if( needEscape ) blob_append(pBlob, &cQuote, 1);
}

/*
** A read(2)-like impl for the Blob class. Reads (copies) up to nLen
** bytes from pIn, starting at position pIn->iCursor, and copies them
** to pDest (which must be valid memory at least nLen bytes long).
**

      blob_reset(&nameFile1);
      blob_appendf(&nameFile1, "%s~%d", zFile2, cnt++);
    }while( file_access(blob_str(&nameFile1),F_OK)==0 );
    blob_write_to_file(pFile1, blob_str(&nameFile1));

    /* Construct the external diff command */
    blob_zero(&cmd);
    blob_append(&cmd, zDiffCmd, -1);
    if( fSwapDiff ){
      blob_append_escaped_arg(&cmd, zFile2);

      blob_append_escaped_arg(&cmd, blob_str(&nameFile1));
    }else{
      blob_append_escaped_arg(&cmd, blob_str(&nameFile1));

      blob_append_escaped_arg(&cmd, zFile2);
    }

    /* Run the external diff command */
    fossil_system(blob_str(&cmd));

    /* Delete the temporary file and clean up memory used */
    file_delete(blob_str(&nameFile1));

    file_tempname(&temp1, blob_str(&prefix1));
    file_tempname(&temp2, blob_str(&prefix2));
    blob_write_to_file(pFile1, blob_str(&temp1));
    blob_write_to_file(pFile2, blob_str(&temp2));

    /* Construct the external diff command */
    blob_zero(&cmd);


    blob_append(&cmd, zDiffCmd, -1);
    blob_append_escaped_arg(&cmd, blob_str(&temp1));
    blob_append_escaped_arg(&cmd, blob_str(&temp2));

    /* Run the external diff command */
    fossil_system(blob_str(&cmd));

    /* Delete the temporary file and clean up memory used */
    file_delete(blob_str(&temp1));
    file_delete(blob_str(&temp2));

  if( pnRcvd ) *pnRcvd = transport.nRcvd;
  if( resetFlag ){
    transport.nSent = 0;
    transport.nRcvd = 0;
  }
}














/*
** Default SSH command
*/
#ifdef _WIN32
static const char zDefaultSshCmd[] = "plink -ssh -T";
#else
static const char zDefaultSshCmd[] = "ssh -e none -T";
#endif

/*
** SSH initialization of the transport layer
*/
int transport_ssh_open(UrlData *pUrlData){
  /* For SSH we need to create and run SSH fossil http
  ** to talk to the remote machine.
  */
  char *zSsh;        /* The base SSH command */
  Blob zCmd;         /* The SSH command */
  char *zHost;       /* The host name to contact */


  socket_ssh_resolve_addr(pUrlData);
  zSsh = db_get("ssh-command", zDefaultSshCmd);
  blob_init(&zCmd, zSsh, -1);
  if( pUrlData->port!=pUrlData->dfltPort && pUrlData->port ){
#ifdef _WIN32
    blob_appendf(&zCmd, " -P %d", pUrlData->port);
#else
    blob_appendf(&zCmd, " -p %d", pUrlData->port);
#endif
  }




  if( pUrlData->user && pUrlData->user[0] ){
    zHost = mprintf("%s@%s", pUrlData->user, pUrlData->name);
    blob_append_escaped_arg(&zCmd, zHost);
    fossil_free(zHost);
  }else{
    blob_append_escaped_arg(&zCmd, pUrlData->name);
  }




  blob_append_escaped_arg(&zCmd, pUrlData->fossil);
  blob_append(&zCmd, " test-http", 10);
  if( pUrlData->path && pUrlData->path[0] ){
    blob_append_escaped_arg(&zCmd, pUrlData->path);

  }else{
    fossil_fatal("ssh:// URI does not specify a path to the repository");
  }
  if( g.fSshTrace ){
    fossil_print("%s\n", blob_str(&zCmd));  /* Show the whole SSH command */
  }

  popen2(blob_str(&zCmd), &sshIn, &sshOut, &sshPid);
  if( sshPid==0 ){
    socket_set_errmsg("cannot start ssh tunnel using [%b]", &zCmd);
  }
  blob_reset(&zCmd);
  return sshPid==0;
}