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diff --git a/lib/tftp/doc/src/tftp.xml b/lib/tftp/doc/src/tftp.xml new file mode 100644 index 0000000000..481e5446ad --- /dev/null +++ b/lib/tftp/doc/src/tftp.xml @@ -0,0 +1,599 @@ +<?xml version="1.0" encoding="utf-8" ?> +<!DOCTYPE erlref SYSTEM "erlref.dtd"> + +<erlref> + <header> + <copyright> + <year>2006</year><year>2018</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + Licensed 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. + + </legalnotice> + + <title>tftp</title> + <prepared></prepared> + <docno></docno> + <date></date> + <rev></rev> + </header> + <module>tftp</module> + <modulesummary>Trivial FTP.</modulesummary> + <description> + <p>Interface module for the <c>tftp</c> application.</p> + </description> + + <section> + <marker id="options"></marker> + <title>DATA TYPES</title> + <p><c>ServiceConfig = Options</c></p> + <p><c>Options = [option()]</c></p> + <p>Most of the options are common for both the client and the server + side, but some of them differs a little. + The available <c>option()</c>s are as follows:</p> + <taglist> + <tag><c>{debug, Level}</c></tag> + <item> + <p><c>Level = none | error | warning | brief | normal | verbose | all</c></p> + <p>Controls the level of debug printouts. + Default is <c>none</c>.</p> + </item> + <tag><c>{host, Host}</c></tag> + <item> + <p><c>Host = hostname()</c>, see + <seealso marker="kernel:inet">inet(3)</seealso>.</p> + <p>The name or IP address of the host where the TFTP daemon + resides. This option is only used by the client.</p> + </item> + <tag><c>{port, Port}</c></tag> + <item> + <p><c>Port = int()</c></p> + <p>The TFTP port where the daemon listens. Defaults is + the standardized number 69. On the server side, it can + sometimes make sense to set it to 0, meaning that + the daemon just picks a free port (which one is + returned by function <c>info/1</c>).</p> + <p>If a socket is connected already, option + <c>{udp, [{fd, integer()}]}</c> can be used to pass the + open file descriptor to <c>gen_udp</c>. This can be automated + by using a command-line argument stating the + prebound file descriptor number. For example, if the + port is 69 and file descriptor 22 is opened by + <c>setuid_socket_wrap</c>, the command-line argument + "-tftpd_69 22" triggers the prebound file + descriptor 22 to be used instead of opening port 69. + The UDP option <c>{udp, [{fd, 22}]}</c> is automatically added. + See <c>init:get_argument/</c> about command-line arguments and + <c>gen_udp:open/2</c> about UDP options.</p> + </item> + <tag><c>{port_policy, Policy}</c></tag> + <item> + <p><c>Policy = random | Port | {range, MinPort, MaxPort}</c></p> + <p><c>Port = MinPort = MaxPort = int()</c></p> + <p>Policy for the selection of the temporary port that is used + by the server/client during the file transfer. Default is + <c>random</c>, which is the standardized policy. With this + policy a randomized free port is used. A single port or a range + of ports can be useful if the protocol passes through a + firewall.</p> + </item> + <tag><c>{udp, Options}</c></tag> + <item> + <p><c>Options = [Opt]</c>, see + <seealso marker="kernel:gen_udp#open/1">gen_udp:open/2</seealso>.</p> + </item> + <tag><c>{use_tsize, Bool}</c></tag> + <item> + <p><c>Bool = bool()</c></p> + <p>Flag for automated use of option <c>tsize</c>. With + this set to <c>true</c>, the <c>write_file/3</c> client + determines the filesize and sends it to the server as + the standardized <c>tsize</c> option. A <c>read_file/3</c> + client acquires only a filesize from the server by sending + a zero <c>tsize</c>.</p> + </item> + <tag><c>{max_tsize, MaxTsize}</c></tag> + <item> + <p><c>MaxTsize = int() | infinity</c></p> + <p>Threshold for the maximal filesize in bytes. The transfer + is aborted if the limit is exceeded. + Default is <c>infinity</c>.</p> + </item> + <tag><c>{max_conn, MaxConn}</c></tag> + <item> + <p><c>MaxConn = int() | infinity</c></p> + <p>Threshold for the maximal number of active connections. + The daemon rejects the setup of new connections if + the limit is exceeded. Default is <c>infinity</c>.</p> + </item> + <tag><c>{TftpKey, TftpVal}</c></tag> + <item> + <p><c>TftpKey = string()</c> <br></br> +<c>TftpVal = string()</c></p> + <p>Name and value of a TFTP option.</p> + </item> + <tag><c>{reject, Feature}</c></tag> + <item> + <p><c>Feature = Mode | TftpKey</c> <br></br> +<c> Mode = read | write</c> <br></br> +<c> TftpKey = string()</c></p> + <p>Controls which features to reject. This is + mostly useful for the server as it can restrict the use + of certain TFTP options or read/write access.</p> + </item> + <tag><c>{callback, {RegExp, Module, State}}</c></tag> + <item> + <p><c>RegExp = string()</c> <br></br> +<c>Module = atom()</c> <br></br> +<c>State = term()</c></p> + <p>Registration of a callback module. When a file is to be + transferred, its local filename is matched to the regular + expressions of the registered callbacks. The first matching + callback is used during the transfer. See + <seealso marker="#read_file/3">read_file/3</seealso> and + <seealso marker="#write_file/3">write_file/3</seealso>. + </p> + <p>The callback module must implement the <c>tftp</c> behavior, see + <seealso marker="#tftp_callback">CALLBACK FUNCTIONS</seealso>.</p> + </item> + + <tag><c>{logger, Module}</c></tag> + <item> + <p><c>Module = module()()</c></p> + + <p>Callback module for customized logging of errors, warnings, and + info messages. The callback module must implement the + <c>tftp_logger</c> behavior, see + <seealso marker="#tftp_logger">LOGGER FUNCTIONS</seealso>. + The default module is <c>tftp_logger</c>.</p> + </item> + + <tag><c>{max_retries, MaxRetries}</c></tag> + <item> + <p><c>MaxRetries = int()</c></p> + + <p>Threshold for the maximal number of retries. By default + the server/client tries to resend a message up to + five times when the time-out expires.</p> + </item> + </taglist> + </section> + + <funcs> + <func> + <name>change_config(daemons, Options) -> [{Pid, Result}]</name> + <fsummary>Changes configuration for all daemons. + </fsummary> + <type> + <v>Options = [option()]</v> + <v>Pid = pid()</v> + <v>Result = ok | {error, Reason}</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Changes configuration for all TFTP daemon processes. </p> + </desc> + </func> + + <func> + <name>change_config(servers, Options) -> [{Pid, Result}]</name> + <fsummary>Changes configuration for all servers. + </fsummary> + <type> + <v>Options = [option()]</v> + <v>Pid = pid()</v> + <v>Result = ok | {error, Reason}</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Changes configuration for all TFTP server processes.</p> + </desc> + </func> + + <func> + <name>change_config(Pid, Options) -> Result</name> + <fsummary>Changes configuration for a TFTP daemon, server, + or client process.</fsummary> + <type> + <v>Pid = pid()</v> + <v>Options = [option()]</v> + <v>Result = ok | {error, Reason}</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Changes configuration for a TFTP daemon, server, or client process.</p> + </desc> + </func> + + <func> + <name>info(daemons) -> [{Pid, Options}]</name> + <fsummary>Returns information about all daemons.</fsummary> + <type> + <v>Pid = [pid()()]</v> + <v>Options = [option()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Returns information about all TFTP daemon processes.</p> + </desc> + </func> + + <func> + <name>info(servers) -> [{Pid, Options}]</name> + <fsummary>Returns information about all servers.</fsummary> + <type> + <v>Pid = [pid()()]</v> + <v>Options = [option()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Returns information about all TFTP server processes. </p> + </desc> + </func> + + <func> + <name>info(Pid) -> {ok, Options} | {error, Reason}</name> + <fsummary>Returns information about a daemon, server, or client process.</fsummary> + <type> + <v>Options = [option()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Returns information about a TFTP daemon, server, or client process.</p> + </desc> + </func> + + <func> + <name>read_file(RemoteFilename, LocalFilename, Options) -> {ok, LastCallbackState} | {error, Reason}</name> + <fsummary>Reads a (virtual) file from a TFTP server.</fsummary> + <type> + <v>RemoteFilename = string()</v> + <v>LocalFilename = binary | string()</v> + <v>Options = [option()]</v> + <v>LastCallbackState = term()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Reads a (virtual) file <c>RemoteFilename</c> from a TFTP + server.</p> + <p>If <c>LocalFilename</c> is the atom <c>binary</c>, + <c>tftp_binary</c> is used as callback module. It concatenates + all transferred blocks and returns them as one single binary + in <c>LastCallbackState</c>.</p> + <p>If <c>LocalFilename</c> is a string and there are no + registered callback modules, <c>tftp_file</c> is used as + callback module. It writes each transferred block to the file + named <c>LocalFilename</c> and returns the number of + transferred bytes in <c>LastCallbackState</c>.</p> + <p>If <c>LocalFilename</c> is a string and there are registered + callback modules, <c>LocalFilename</c> is tested against + the regexps of these and the callback module corresponding to + the first match is used, or an error tuple is returned if no + matching regexp is found.</p> + </desc> + </func> + + <func> + <name>start(Options) -> {ok, Pid} | {error, Reason}</name> + <fsummary>Starts a daemon process.</fsummary> + <type> + <v>Options = [option()]</v> + <v>Pid = pid()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Starts a daemon process listening for UDP packets on a + port. When it receives a request for read or write, it spawns + a temporary server process handling the actual transfer + of the (virtual) file.</p> + </desc> + </func> + + <func> + <name>write_file(RemoteFilename, LocalFilename, Options) -> {ok, LastCallbackState} | {error, Reason}</name> + <fsummary>Writes a (virtual) file to a TFTP server.</fsummary> + <type> + <v>RemoteFilename = string()</v> + <v>LocalFilename = binary() | string()</v> + <v>Options = [option()]</v> + <v>LastCallbackState = term()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Writes a (virtual) file <c>RemoteFilename</c> to a TFTP + server.</p> + <p>If <c>LocalFilename</c> is a binary, <c>tftp_binary</c> is + used as callback module. The binary is transferred block by + block and the number of transferred bytes is returned in + <c>LastCallbackState</c>.</p> + <p>If <c>LocalFilename</c> is a string and there are no + registered callback modules, <c>tftp_file</c> is used as + callback module. It reads the file named <c>LocalFilename</c> + block by block and returns the number of transferred bytes + in <c>LastCallbackState</c>.</p> + <p>If <c>LocalFilename</c> is a string and there are registered + callback modules, <c>LocalFilename</c> is tested against + the regexps of these and the callback module corresponding to + the first match is used, or an error tuple is returned if no + matching regexp is found.</p> + </desc> + </func> + </funcs> + + <section> + <marker id="tftp_callback"></marker> + <title>CALLBACK FUNCTIONS</title> + <p>A <c>tftp</c> callback module is to be implemented as a + <c>tftp</c> behavior and export the functions listed + in the following.</p> + <p>On the server side, the callback interaction starts with a call to + <c>open/5</c> with the registered initial callback state. + <c>open/5</c> is expected to open the (virtual) file. Then either + function <c>read/1</c> or <c>write/2</c> is invoked + repeatedly, once per transferred block. At each function call, + the state returned from the previous call is obtained. When + the last block is encountered, function <c>read/1</c> or + <c>write/2</c> is expected to close the (virtual) file + and return its last state. Function <c>abort/3</c> is only + used in error situations. Function <c>prepare/5</c> is not used on + the server side.</p> + <p>On the client side, the callback interaction is the same, but it + starts and ends a bit differently. It starts with a call to + <c>prepare/5</c> with the same arguments as <c>open/5</c> takes. + <c>prepare/5</c> is expected to validate the TFTP options + suggested by the user and to return the subset of them that it + accepts. Then the options are sent to the server, which performs + the same TFTP option negotiation procedure. The options that are + accepted by the server are forwarded to function <c>open/5</c> + on the client side. On the client side, function <c>open/5</c> + must accept all option as-is or reject the transfer. Then + the callback interaction follows the same pattern as described + for the server side. When the last block is encountered in + <c>read/1</c> or <c>write/2</c>, the returned state is forwarded to + the user and returned from <c>read_file</c>/3 or + <c>write_file/3</c>.</p> + + <p> If a callback (performing the file access + in the TFTP server) takes too long time (more than + the double TFTP time-out), the server aborts the + connection and sends an error reply to the client. + This implies that the server releases resources + attached to the connection faster than before. The + server simply assumes that the client has given + up.</p> + + <p>If the TFTP server receives yet another request from + the same client (same host and port) while it + already has an active connection to the client, it + ignores the new request if the request is + equal to the first one (same filename and options). + This implies that the (new) client will be served + by the already ongoing connection on the server + side. By not setting up yet another connection, in + parallel with the ongoing one, the server + consumes less resources.</p> + + <marker id="prepare"></marker> + </section> + + <funcs> + <func> + <name>Module:abort(Code, Text, State) -> ok</name> + <fsummary>Aborts the file transfer.</fsummary> + <type> + <v>Code = undef | enoent | eacces | enospc</v> + <v> | badop | eexist | baduser | badopt</v> + <v> | int()</v> + <v>Text = string()</v> + <v>State = term()</v> + </type> + <desc> + <p>Invoked when the file transfer is aborted.</p> + <p>The callback function is expected to clean + up its used resources after the aborted file + transfer, such as closing open file + descriptors and so on. The function is not + invoked if any of the other callback + functions returns an error, as it is + expected that they already have cleaned up + the necessary resources. However, it is + invoked if the functions fail (crash).</p> + </desc> + </func> + + <func> + <name>Module:open(Peer, Access, Filename, Mode, SuggestedOptions, State) -> {ok, AcceptedOptions, NewState} | {error, {Code, Text}}</name> + <fsummary>Opens a file for read or write access.</fsummary> + <type> + <v>Peer = {PeerType, PeerHost, PeerPort}</v> + <v>PeerType = inet | inet6</v> + <v>PeerHost = ip_address()</v> + <v>PeerPort = integer()</v> + <v>Access = read | write</v> + <v>Filename = string()</v> + <v>Mode = string()</v> + <v>SuggestedOptions = AcceptedOptions = [{Key, Value}]</v> + <v> Key = Value = string()</v> + <v>State = InitialState | term()</v> + <v> InitialState = [] | [{root_dir, string()}]</v> + <v>NewState = term()</v> + <v>Code = undef | enoent | eacces | enospc</v> + <v> | badop | eexist | baduser | badopt</v> + <v> | int()</v> + <v>Text = string()</v> + </type> + <desc> + <p>Opens a file for read or write access.</p> + <p>On the client side, where the <c>open/5</c> call has been + preceded by a call to <c>prepare/5</c>, all options must be + accepted or rejected.</p> + <p>On the server side, where there is no preceding + <c>prepare/5</c> call, no new options can be added, but + those present in <c>SuggestedOptions</c> can be + omitted or replaced with new values in <c>AcceptedOptions</c>.</p> + + <marker id="read"></marker> + </desc> + </func> + + <func> + <name>Module:prepare(Peer, Access, Filename, Mode, SuggestedOptions, InitialState) -> {ok, AcceptedOptions, NewState} | {error, {Code, Text}}</name> + <fsummary>Prepares to open a file on the client side.</fsummary> + <type> + <v>Peer = {PeerType, PeerHost, PeerPort}</v> + <v>PeerType = inet | inet6</v> + <v>PeerHost = ip_address()</v> + <v>PeerPort = integer()</v> + <v>Access = read | write</v> + <v>Filename = string()</v> + <v>Mode = string()</v> + <v>SuggestedOptions = AcceptedOptions = [{Key, Value}]</v> + <v> Key = Value = string()</v> + <v>InitialState = [] | [{root_dir, string()}]</v> + <v>NewState = term()</v> + <v>Code = undef | enoent | eacces | enospc</v> + <v> | badop | eexist | baduser | badopt</v> + <v> | int()</v> + <v>Text = string()</v> + </type> + <desc> + <p>Prepares to open a file on the client side.</p> + <p>No new options can be added, but those present in + <c>SuggestedOptions</c> can be omitted or replaced with new + values in <c>AcceptedOptions</c>.</p> + <p>This is followed by a call to <c>open/4</c> before any + read/write access is performed. <c>AcceptedOptions</c> is + sent to the server, which replies with the options that it + accepts. These are then forwarded to <c>open/4</c> as + <c>SuggestedOptions</c>.</p> + + <marker id="open"></marker> + </desc> + </func> + + <func> + <name>Module:read(State) -> {more, Bin, NewState} | {last, Bin, FileSize} | {error, {Code, Text}}</name> + <fsummary>Reads a chunk from the file.</fsummary> + <type> + <v>State = NewState = term()</v> + <v>Bin = binary()</v> + <v>FileSize = int()</v> + <v>Code = undef | enoent | eacces | enospc</v> + <v> | badop | eexist | baduser | badopt</v> + <v> | int()</v> + <v>Text = string()</v> + </type> + <desc> + <p>Reads a chunk from the file.</p> + <p>The callback function is expected to close + the file when the last file chunk is + encountered. When an error is encountered, + the callback function is expected to clean + up after the aborted file transfer, such as + closing open file descriptors, and so on. In both + cases there will be no more calls to any of + the callback functions.</p> + + <marker id="write"></marker> + </desc> + </func> + + <func> + <name>Module:write(Bin, State) -> {more, NewState} | {last, FileSize} | {error, {Code, Text}}</name> + <fsummary>Writes a chunk to the file.</fsummary> + <type> + <v>Bin = binary()</v> + <v>State = NewState = term()</v> + <v>FileSize = int()</v> + <v>Code = undef | enoent | eacces | enospc</v> + <v> | badop | eexist | baduser | badopt</v> + <v> | int()</v> + <v>Text = string()</v> + </type> + <desc> + <p>Writes a chunk to the file.</p> + <p>The callback function is expected to close + the file when the last file chunk is + encountered. When an error is encountered, + the callback function is expected to clean + up after the aborted file transfer, such as + closing open file descriptors, and so on. In both + cases there will be no more calls to any of + the callback functions.</p> + + <marker id="abort"></marker> + </desc> + </func> + </funcs> + + <section> + <marker id="tftp_logger"></marker> + <title>LOGGER FUNCTIONS</title> + + <p>A <c>tftp_logger</c> callback module is to be implemented as a + <c>tftp_logger</c> behavior and export the following functions:</p> + + <marker id="error_msg"></marker> + </section> + + <funcs> + <func> + <name>Logger:error_msg(Format, Data) -> ok | exit(Reason)</name> + <fsummary>Logs an error message.</fsummary> + <type> + <v>Format = string()</v> + <v>Data = [term()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Logs an error message. + See <c>error_logger:error_msg/2</c> for details.</p> + + <marker id="warning_msg"></marker> + </desc> + </func> + + <func> + <name>Logger:info_msg(Format, Data) -> ok | exit(Reason)</name> + <fsummary>Logs an info message.</fsummary> + <type> + <v>Format = string()</v> + <v>Data = [term()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Logs an info message. + See <c>error_logger:info_msg/2</c> for details.</p> + </desc> + </func> + + <func> + <name>Logger:warning_msg(Format, Data) -> ok | exit(Reason)</name> + <fsummary>Logs a warning message.</fsummary> + <type> + <v>Format = string()</v> + <v>Data = [term()]</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Logs a warning message. + See <c>error_logger:warning_msg/2</c> for details.</p> + + <marker id="info_msg"></marker> + </desc> + </func> + </funcs> +</erlref> + + |