TNetFile
class description - source file - inheritance tree
private:
TNetFile()
void Init(Bool_t create)
virtual void Print(const Option_t* option) const
void PrintError(const char* where, Int_t err)
Int_t Recv(Int_t& status, EMessageTypes& kind)
virtual Int_t SysClose(Int_t fd)
virtual Int_t SysOpen(const char* pathname, Int_t flags, UInt_t mode)
virtual Int_t SysStat(Int_t fd, Long_t* id, Long_t* size, Long_t* flags, Long_t* modtime)
public:
TNetFile(const char* url, const Option_t* option, const char* ftitle, Int_t compress = 1, Int_t netopt = 0)
virtual ~TNetFile()
static TClass* Class()
virtual void Close(const Option_t* option)
virtual void Flush()
Int_t GetErrorCode() const
virtual TClass* IsA() const
virtual Bool_t IsOpen() const
virtual Bool_t ReadBuffer(char* buf, Int_t len)
virtual Int_t ReOpen(const Option_t* mode)
virtual void Seek(Seek_t offset, TFile::ERelativeTo pos = kBeg)
virtual void ShowMembers(TMemberInspector& insp, char* parent)
virtual void Streamer(TBuffer& b)
void StreamerNVirtual(TBuffer& b)
virtual Bool_t WriteBuffer(const char* buf, Int_t len)
private:
TUrl fUrl URL of file
TString fUser remote user name
Seek_t fOffset seek offset
TSocket* fSocket connection to rootd server
Int_t fProtocol rootd protocol level
Int_t fErrorCode error code returned by rootd (matching gRootdErrStr)
static Int_t fgClientProtocol client protocol level
TNetFile
A TNetFile is like a normal TFile except that it reads and writes
its data via a rootd server (for more on the rootd daemon see the
source files root/rootd/src/*.cxx). TNetFile file names are in
standard URL format with protocol "root" or "roots". The following
are valid TNetFile URL's:
roots://hpsalo/files/aap.root
root://hpbrun.cern.ch/root/hsimple.root
root://pcna49a:5151/~na49/data/run821.root
root://pcna49d.cern.ch:5050//v1/data/run810.root
The only difference with the well known httpd URL's is that the root
of the remote file tree is the user's home directory. Therefore an
absolute pathname requires a // after the host or port specifier
(see last example). Further the expansion of the standard shell
characters, like ~, $, .., are handled as expected.
TNetFile (actually TUrl) uses 1094 as default port for rootd.
Connecting to a rootd requires the remote user id and password.
TNetFile allows three ways for you to provide your login:
1) Setting it globally via the static functions:
TAuthenticate::SetGlobalUser() and
TAuthenticate::SetGlobalPasswd()
2) Getting it from the ~/.netrc file (same file as used by ftp)
3) Command line prompt
The different methods will be tried in the order given above.
On machines with AFS rootd will authenticate using AFS (if it was
compiled with AFS support).
If the protocol is specified as "roots" a secure authetication
method will be used. The secure method uses the SRP, Secure Remote
Passwords, package. SRP uses a so called "asymmetric key exchange
protocol" in which no passwords are ever send over the wire. This
protocol is safe against all known security attacks. For more see:
NetFile
If the protocol is specified as "rootk" kerberos5 will be used for
authentication.
The rootd daemon lives in the directory $ROOTSYS/bin. It can be
started either via inetd or by hand from the command line (no need
to be super user). For more info about rootd see the web page:
NetFile
TNetFile(const char *url, Option_t *option, const char *ftitle,
Int_t compress, Int_t netopt)
: TFile(url, "NET", ftitle, compress), fUrl(url)
Create a NetFile object. A net file is the same as a TFile
except that it is being accessed via a rootd server. The url
argument must be of the form: root[s|k]://host.dom.ain/file.root.
When protocol is "roots" try using SRP authentication.
When protocol is "rootk" try using kerberos5 authentication.
If the file specified in the URL does not exist, is not accessable
or can not be created the kZombie bit will be set in the TNetFile
object. Use IsZombie() to see if the file is accessable.
If the remote daemon thinks the file is still connected, while you are
sure this is not the case you can force open the file by preceding the
option argument with an "-", e.g.: "-recreate". Do this only
in cases when you are very sure nobody else is using the file.
To bypass the writelock on a file, to allow the reading of a file
that is being written by another process, explicitely specify the
"+read" option ("read" being the default option).
The netopt argument can be used to specify the size of the tcp window in
bytes (for more info see: http://www.psc.edu/networking/perf_tune.html).
The default and minimum tcp window size is 65535 bytes.
If netopt < -1 then |netopt| is the number of parallel sockets that will
be used to connect to rootd. This option should be used on fat pipes
(i.e. high bandwidth, high latency links). The ideal number of parallel
sockets depends on the bandwidth*delay product. Generally 5-7 is a good
number.
For a description of the option and other arguments see the TFile ctor.
The preferred interface to this constructor is via TFile::Open().
~TNetFile()
TNetFile dtor. Send close message and close socket.
Int_t SysOpen(const char * /*file*/, Int_t /*flags*/, UInt_t /*mode*/)
Open a remote file. Requires fOption to be set correctly.
Int_t SysClose(Int_t /*fd*/)
Close currently open file.
Int_t SysStat(Int_t, Long_t *id, Long_t *size, Long_t *flags, Long_t *modtime)
Return file stat information. The interface and return value is
identical to TSystem::GetPathInfo().
void Close(Option_t *opt)
Close remote file.
void Flush()
Flush file to disk.
void Init(Bool_t create)
Initialize a TNetFile object.
Bool_t IsOpen() const
Retruns kTRUE if file is open, kFALSE otherwise.
void Print(Option_t *) const
Print some info about the net file.
void PrintError(const char *where, Int_t err)
Print error string depending on error code.
Int_t ReOpen(Option_t *mode)
Reopen a file with a different access mode, like from READ to
UPDATE or from NEW, CREATE, RECREATE, UPDATE to READ. Thus the
mode argument can be either "READ" or "UPDATE". The method returns
0 in case the mode was successfully modified, 1 in case the mode
did not change (was already as requested or wrong input arguments)
and -1 in case of failure, in which case the file cannot be used
anymore.
Bool_t ReadBuffer(char *buf, Int_t len)
Read specified byte range from remote file via rootd daemon.
Returns kTRUE in case of error.
Bool_t WriteBuffer(const char *buf, Int_t len)
Write specified byte range to remote file via rootd daemon.
Returns kTRUE in case of error.
Int_t Recv(Int_t &status, EMessageTypes &kind)
Return status from rootd server and message kind. Returns -1 in
case of error otherwise 8 (sizeof 2 words, status and kind).
void Seek(Seek_t offset, ERelativeTo pos)
Set position from where to start reading.
Inline Functions
TNetFile TNetFile(const char* url, const Option_t* option, const char* ftitle, Int_t compress = 1, Int_t netopt = 0)
Int_t GetErrorCode() const
TClass* Class()
TClass* IsA() const
void ShowMembers(TMemberInspector& insp, char* parent)
void Streamer(TBuffer& b)
void StreamerNVirtual(TBuffer& b)
Author: Fons Rademakers 14/08/97
Last update: root/net:$Name: $:$Id: TNetFile.cxx,v 1.32 2003/05/05 09:36:27 rdm Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *
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