1.\" Copyright (c) 1998 Dag-Erling Co�dan Sm�rgrav 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/lib/libfetch/fetch.3,v 1.11.2.29 2003/06/13 14:36:58 trhodes Exp $ 26.\" 27.Dd July 1, 1998 28.Dt FETCH 3 29.Os 30.Sh NAME 31.Nm fetchMakeURL , 32.Nm fetchParseURL , 33.Nm fetchFreeURL , 34.Nm fetchXGetURL , 35.Nm fetchGetURL , 36.Nm fetchPutURL , 37.Nm fetchStatURL , 38.Nm fetchListURL , 39.Nm fetchXGet , 40.Nm fetchGet , 41.Nm fetchPut , 42.Nm fetchStat , 43.Nm fetchList , 44.Nm fetchXGetFile , 45.Nm fetchGetFile , 46.Nm fetchPutFile , 47.Nm fetchStatFile , 48.Nm fetchListFile , 49.Nm fetchXGetHTTP , 50.Nm fetchGetHTTP , 51.Nm fetchPutHTTP , 52.Nm fetchStatHTTP , 53.Nm fetchListHTTP , 54.Nm fetchXGetFTP , 55.Nm fetchGetFTP , 56.Nm fetchPutFTP , 57.Nm fetchStatFTP , 58.Nm fetchListFTP 59.Nd file transfer functions 60.Sh LIBRARY 61.Lb libfetch 62.Sh SYNOPSIS 63.In sys/param.h 64.In stdio.h 65.In fetch.h 66.Ft struct url * 67.Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd" 68.Ft struct url * 69.Fn fetchParseURL "const char *URL" 70.Ft void 71.Fn fetchFreeURL "struct url *u" 72.Ft FILE * 73.Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags" 74.Ft FILE * 75.Fn fetchGetURL "const char *URL" "const char *flags" 76.Ft FILE * 77.Fn fetchPutURL "const char *URL" "const char *flags" 78.Ft int 79.Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags" 80.Ft struct url_ent * 81.Fn fetchListURL "const char *URL" "const char *flags" 82.Ft FILE * 83.Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags" 84.Ft FILE * 85.Fn fetchGet "struct url *u" "const char *flags" 86.Ft FILE * 87.Fn fetchPut "struct url *u" "const char *flags" 88.Ft int 89.Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags" 90.Ft struct url_ent * 91.Fn fetchList "struct url *u" "const char *flags" 92.Ft FILE * 93.Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags" 94.Ft FILE * 95.Fn fetchGetFile "struct url *u" "const char *flags" 96.Ft FILE * 97.Fn fetchPutFile "struct url *u" "const char *flags" 98.Ft int 99.Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags" 100.Ft struct url_ent * 101.Fn fetchListFile "struct url *u" "const char *flags" 102.Ft FILE * 103.Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags" 104.Ft FILE * 105.Fn fetchGetHTTP "struct url *u" "const char *flags" 106.Ft FILE * 107.Fn fetchPutHTTP "struct url *u" "const char *flags" 108.Ft int 109.Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags" 110.Ft struct url_ent * 111.Fn fetchListHTTP "struct url *u" "const char *flags" 112.Ft FILE * 113.Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags" 114.Ft FILE * 115.Fn fetchGetFTP "struct url *u" "const char *flags" 116.Ft FILE * 117.Fn fetchPutFTP "struct url *u" "const char *flags" 118.Ft int 119.Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags" 120.Ft struct url_ent * 121.Fn fetchListFTP "struct url *u" "const char *flags" 122.Sh DESCRIPTION 123These functions implement a high-level library for retrieving and 124uploading files using Uniform Resource Locators (URLs). 125.Pp 126.Fn fetchParseURL 127takes a URL in the form of a null-terminated string and splits it into 128its components function according to the Common Internet Scheme Syntax 129detailed in RFC1738. 130A regular expression which produces this syntax is: 131.Bd -literal 132 <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? 133.Ed 134.Pp 135If the URL does not seem to begin with a scheme name, the following 136syntax is assumed: 137.Bd -literal 138 ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? 139.Ed 140.Pp 141Note that some components of the URL are not necessarily relevant to 142all URL schemes. 143For instance, the file scheme only needs the <scheme> and <document> 144components. 145.Pp 146.Fn fetchMakeURL 147and 148.Fn fetchParseURL 149return a pointer to a 150.Vt url 151structure, which is defined as follows in 152.Aq Pa fetch.h : 153.Bd -literal 154#define URL_SCHEMELEN 16 155#define URL_USERLEN 256 156#define URL_PWDLEN 256 157 158struct url { 159 char scheme[URL_SCHEMELEN+1]; 160 char user[URL_USERLEN+1]; 161 char pwd[URL_PWDLEN+1]; 162 char host[MAXHOSTNAMELEN+1]; 163 int port; 164 char *doc; 165 off_t offset; 166 size_t length; 167}; 168.Ed 169.Pp 170The pointer returned by 171.Fn fetchMakeURL 172or 173.Fn fetchParseURL 174should be freed using 175.Fn fetchFreeURL . 176.Pp 177.Fn fetchXGetURL , 178.Fn fetchGetURL , 179and 180.Fn fetchPutURL 181constitute the recommended interface to the 182.Nm fetch 183library. 184They examine the URL passed to them to determine the transfer 185method, and call the appropriate lower-level functions to perform the 186actual transfer. 187.Fn fetchXGetURL 188also returns the remote document's metadata in the 189.Vt url_stat 190structure pointed to by the 191.Fa us 192argument. 193.Pp 194The 195.Fa flags 196argument is a string of characters which specify transfer options. 197The 198meaning of the individual flags is scheme-dependent, and is detailed 199in the appropriate section below. 200.Pp 201.Fn fetchStatURL 202attempts to obtain the requested document's metadata and fill in the 203structure pointed to by its second argument. 204The 205.Vt url_stat 206structure is defined as follows in 207.Aq Pa fetch.h : 208.Bd -literal 209struct url_stat { 210 off_t size; 211 time_t atime; 212 time_t mtime; 213}; 214.Ed 215.Pp 216If the size could not be obtained from the server, the 217.Fa size 218field is set to -1. 219If the modification time could not be obtained from the server, the 220.Fa mtime 221field is set to the epoch. 222If the access time could not be obtained from the server, the 223.Fa atime 224field is set to the modification time. 225.Pp 226.Fn fetchListURL 227attempts to list the contents of the directory pointed to by the URL 228provided. 229If successful, it returns a malloced array of 230.Vt url_ent 231structures. 232The 233.Vt url_ent 234structure is defined as follows in 235.Aq Pa fetch.h : 236.Bd -literal 237struct url_ent { 238 char name[MAXPATHLEN]; 239 struct url_stat stat; 240}; 241.Ed 242.Pp 243The list is terminated by an entry with an empty name. 244.Pp 245The pointer returned by 246.Fn fetchListURL 247should be freed using 248.Fn free . 249.Pp 250.Fn fetchXGet , 251.Fn fetchGet , 252.Fn fetchPut 253and 254.Fn fetchStat 255are similar to 256.Fn fetchXGetURL , 257.Fn fetchGetURL , 258.Fn fetchPutURL 259and 260.Fn fetchStatURL , 261except that they expect a pre-parsed URL in the form of a pointer to 262a 263.Vt struct url 264rather than a string. 265.Pp 266All of the 267.Fn fetchXGetXXX , 268.Fn fetchGetXXX 269and 270.Fn fetchPutXXX 271functions return a pointer to a stream which can be used to read or 272write data from or to the requested document, respectively. 273Note that 274although the implementation details of the individual access methods 275vary, it can generally be assumed that a stream returned by one of the 276.Fn fetchXGetXXX 277or 278.Fn fetchGetXXX 279functions is read-only, and that a stream returned by one of the 280.Fn fetchPutXXX 281functions is write-only. 282.Sh FILE SCHEME 283.Fn fetchXGetFile , 284.Fn fetchGetFile 285and 286.Fn fetchPutFile 287provide access to documents which are files in a locally mounted file 288system. 289Only the <document> component of the URL is used. 290.Pp 291.Fn fetchXGetFile 292and 293.Fn fetchGetFile 294do not accept any flags. 295.Pp 296.Fn fetchPutFile 297accepts the 298.Ql a 299(append to file) flag. 300If that flag is specified, the data written to 301the stream returned by 302.Fn fetchPutFile 303will be appended to the previous contents of the file, instead of 304replacing them. 305.Sh FTP SCHEME 306.Fn fetchXGetFTP , 307.Fn fetchGetFTP 308and 309.Fn fetchPutFTP 310implement the FTP protocol as described in RFC959. 311.Pp 312If the 313.Ql p 314(passive) flag is specified, a passive (rather than active) connection 315will be attempted. 316.Pp 317If the 318.Ql l 319(low) flag is specified, data sockets will be allocated in the low (or 320default) port range instead of the high port range (see 321.Xr ip 4 ) . 322.Pp 323If the 324.Ql d 325(direct) flag is specified, 326.Fn fetchXGetFTP , 327.Fn fetchGetFTP 328and 329.Fn fetchPutFTP 330will use a direct connection even if a proxy server is defined. 331.Pp 332If no user name or password is given, the 333.Nm fetch 334library will attempt an anonymous login, with user name "anonymous" 335and password "anonymous@<hostname>". 336.Sh HTTP SCHEME 337The 338.Fn fetchXGetHTTP , 339.Fn fetchGetHTTP 340and 341.Fn fetchPutHTTP 342functions implement the HTTP/1.1 protocol. 343With a little luck, there's 344even a chance that they comply with RFC2616 and RFC2617. 345.Pp 346If the 347.Ql d 348(direct) flag is specified, 349.Fn fetchXGetHTTP , 350.Fn fetchGetHTTP 351and 352.Fn fetchPutHTTP 353will use a direct connection even if a proxy server is defined. 354.Pp 355Since there seems to be no good way of implementing the HTTP PUT 356method in a manner consistent with the rest of the 357.Nm fetch 358library, 359.Fn fetchPutHTTP 360is currently unimplemented. 361.Sh AUTHENTICATION 362Apart from setting the appropriate environment variables and 363specifying the user name and password in the URL or the 364.Vt struct url , 365the calling program has the option of defining an authentication 366function with the following prototype: 367.Pp 368.Ft int 369.Fn myAuthMethod "struct url *u" 370.Pp 371The callback function should fill in the 372.Fa user 373and 374.Fa pwd 375fields in the provided 376.Vt struct url 377and return 0 on success, or any other value to indicate failure. 378.Pp 379To register the authentication callback, simply set 380.Va fetchAuthMethod 381to point at it. 382The callback will be used whenever a site requires authentication and 383the appropriate environment variables aren't set. 384.Pp 385This interface is experimental and may be subject to change. 386.Sh RETURN VALUES 387.Fn fetchParseURL 388returns a pointer to a 389.Vt struct url 390containing the individual components of the URL. 391If it is 392unable to allocate memory, or the URL is syntactically incorrect, 393.Fn fetchParseURL 394returns a NULL pointer. 395.Pp 396The 397.Fn fetchStat 398functions return 0 on success and -1 on failure. 399.Pp 400All other functions return a stream pointer which may be used to 401access the requested document, or NULL if an error occurred. 402.Pp 403The following error codes are defined in 404.Aq Pa fetch.h : 405.Bl -tag -width 18n 406.It Bq Er FETCH_ABORT 407Operation aborted 408.It Bq Er FETCH_AUTH 409Authentication failed 410.It Bq Er FETCH_DOWN 411Service unavailable 412.It Bq Er FETCH_EXISTS 413File exists 414.It Bq Er FETCH_FULL 415File system full 416.It Bq Er FETCH_INFO 417Informational response 418.It Bq Er FETCH_MEMORY 419Insufficient memory 420.It Bq Er FETCH_MOVED 421File has moved 422.It Bq Er FETCH_NETWORK 423Network error 424.It Bq Er FETCH_OK 425No error 426.It Bq Er FETCH_PROTO 427Protocol error 428.It Bq Er FETCH_RESOLV 429Resolver error 430.It Bq Er FETCH_SERVER 431Server error 432.It Bq Er FETCH_TEMP 433Temporary error 434.It Bq Er FETCH_TIMEOUT 435Operation timed out 436.It Bq Er FETCH_UNAVAIL 437File is not available 438.It Bq Er FETCH_UNKNOWN 439Unknown error 440.It Bq Er FETCH_URL 441Invalid URL 442.El 443.Pp 444The accompanying error message includes a protocol-specific error code 445and message, e.g. "File is not available (404 Not Found)" 446.Sh ENVIRONMENT 447.Bl -tag -width ".Ev FETCH_BIND_ADDRESS" 448.It Ev FETCH_BIND_ADDRESS 449Specifies a hostname or IP address to which sockets used for outgoing 450connections will be bound. 451.It Ev FTP_LOGIN 452Default FTP login if none was provided in the URL. 453.It Ev FTP_PASSIVE_MODE 454If set to anything but 455.Ql no , 456forces the FTP code to use passive mode. 457.It Ev FTP_PASSWORD 458Default FTP password if the remote server requests one and none was 459provided in the URL. 460.It Ev FTP_PROXY 461URL of the proxy to use for FTP requests. 462The document part is ignored. 463FTP and HTTP proxies are supported; if no scheme is specified, FTP is 464assumed. 465If the proxy is an FTP proxy, 466.Nm libfetch 467will send 468.Ql user@host 469as user name to the proxy, where 470.Ql user 471is the real user name, and 472.Ql host 473is the name of the FTP server. 474.Pp 475If this variable is set to an empty string, no proxy will be used for 476FTP requests, even if the 477.Ev HTTP_PROXY 478variable is set. 479.It Ev ftp_proxy 480Same as 481.Ev FTP_PROXY , 482for compatibility. 483.It Ev HTTP_AUTH 484Specifies HTTP authorization parameters as a colon-separated list of 485items. 486The first and second item are the authorization scheme and realm 487respectively; further items are scheme-dependent. 488Currently, only basic authorization is supported. 489.Pp 490Basic authorization requires two parameters: the user name and 491password, in that order. 492.Pp 493This variable is only used if the server requires authorization and 494no user name or password was specified in the URL. 495.It Ev HTTP_PROXY 496URL of the proxy to use for HTTP requests. 497The document part is ignored. 498Only HTTP proxies are supported for HTTP requests. 499If no port number is specified, the default is 3128. 500.Pp 501Note that this proxy will also be used for FTP documents, unless the 502.Ev FTP_PROXY 503variable is set. 504.It Ev http_proxy 505Same as 506.Ev HTTP_PROXY , 507for compatibility. 508.It Ev HTTP_PROXY_AUTH 509Specifies authorization parameters for the HTTP proxy in the same 510format as the 511.Ev HTTP_AUTH 512variable. 513.Pp 514This variable is used if and only if connected to an HTTP proxy, and 515is ignored if a user and/or a password were specified in the proxy 516URL. 517.It Ev HTTP_REFERER 518Specifies the referrer URL to use for HTTP requests. 519If set to 520.Dq auto , 521the document URL will be used as referrer URL. 522.It Ev HTTP_USER_AGENT 523Specifies the User-Agent string to use for HTTP requests. 524This can be useful when working with HTTP origin or proxy servers that 525differentiate between user agents. 526.It Ev NETRC 527Specifies a file to use instead of 528.Pa ~/.netrc 529to look up login names and passwords for FTP sites. 530See 531.Xr ftp 1 532for a description of the file format. 533This feature is experimental. 534.El 535.Sh EXAMPLES 536To access a proxy server on 537.Pa proxy.example.com 538port 8080, set the 539.Ev HTTP_PROXY 540environment variable in a manner similar to this: 541.Pp 542.Dl HTTP_PROXY=http://proxy.example.com:8080 543.Pp 544If the proxy server requires authentication, there are 545two options available for passing the authentication data. 546The first method is by using the proxy URL: 547.Pp 548.Dl HTTP_PROXY=http://<user>:<pwd>@proxy.example.com:8080 549.Pp 550The second method is by using the 551.Ev HTTP_PROXY_AUTH 552environment variable: 553.Bd -literal -offset indent 554HTTP_PROXY=http://proxy.example.com:8080 555HTTP_PROXY_AUTH=basic:*:<user>:<pwd> 556.Ed 557.Sh SEE ALSO 558.Xr fetch 1 , 559.Xr ftpio 3 , 560.Xr ip 4 561.Rs 562.%A J. Postel 563.%A J. K. Reynolds 564.%D October 1985 565.%B File Transfer Protocol 566.%O RFC959 567.Re 568.Rs 569.%A P. Deutsch 570.%A A. Emtage 571.%A A. Marine. 572.%D May 1994 573.%T How to Use Anonymous FTP 574.%O RFC1635 575.Re 576.Rs 577.%A T. Berners-Lee 578.%A L. Masinter 579.%A M. McCahill 580.%D December 1994 581.%T Uniform Resource Locators (URL) 582.%O RFC1738 583.Re 584.Rs 585.%A R. Fielding 586.%A J. Gettys 587.%A J. Mogul 588.%A H. Frystyk 589.%A L. Masinter 590.%A P. Leach 591.%A T. Berners-Lee 592.%D January 1999 593.%B Hypertext Transfer Protocol -- HTTP/1.1 594.%O RFC2616 595.Re 596.Rs 597.%A J. Franks 598.%A P. Hallam-Baker 599.%A J. Hostetler 600.%A S. Lawrence 601.%A P. Leach 602.%A A. Luotonen 603.%A L. Stewart 604.%D June 1999 605.%B HTTP Authentication: Basic and Digest Access Authentication 606.%O RFC2617 607.Re 608.Sh HISTORY 609The 610.Nm fetch 611library first appeared in 612.Fx 3.0 . 613.Sh AUTHORS 614.An -nosplit 615The 616.Nm fetch 617library was mostly written by 618.An Dag-Erling Co\(:idan Sm\(/orgrav Aq des@FreeBSD.org 619with numerous suggestions from 620.An Jordan K. Hubbard Aq jkh@FreeBSD.org , 621.An Eugene Skepner Aq eu@qub.com 622and other 623.Fx 624developers. 625It replaces the older 626.Nm ftpio 627library written by 628.An Poul-Henning Kamp Aq pkh@FreeBSD.org 629and 630.An Jordan K. Hubbard Aq jkh@FreeBSD.org . 631.Pp 632This manual page was written by 633.An Dag-Erling Co\(:idan Sm\(/orgrav Aq des@FreeBSD.org . 634.Sh BUGS 635Some parts of the library are not yet implemented. 636The most notable 637examples of this are 638.Fn fetchPutHTTP , 639.Fn fetchListHTTP , 640.Fn fetchListFTP 641and FTP proxy support. 642.Pp 643There's no way to select a proxy at run-time other than setting the 644.Ev HTTP_PROXY 645or 646.Ev FTP_PROXY 647environment variables as appropriate. 648.Pp 649.Nm libfetch 650does not understand or obey 305 (Use Proxy) replies. 651.Pp 652Error numbers are unique only within a certain context; the error 653codes used for FTP and HTTP overlap, as do those used for resolver and 654system errors. 655For instance, error code 202 means "Command not 656implemented, superfluous at this site" in an FTP context and 657"Accepted" in an HTTP context. 658.Pp 659.Fn fetchStatFTP 660does not check that the result of an MDTM command is a valid date. 661.Pp 662The man page is incomplete, poorly written and produces badly 663formatted text. 664.Pp 665The error reporting mechanism is unsatisfactory. 666.Pp 667Some parts of the code are not fully reentrant. 668