1.\"- 2.\" Copyright (c) 1998-2011 Dag-Erling Smørgrav 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd November 3, 2012 29.Dt FETCH 3 30.Os 31.Sh NAME 32.Nm fetchMakeURL , 33.Nm fetchParseURL , 34.Nm fetchFreeURL , 35.Nm fetchXGetURL , 36.Nm fetchGetURL , 37.Nm fetchPutURL , 38.Nm fetchStatURL , 39.Nm fetchListURL , 40.Nm fetchXGet , 41.Nm fetchGet , 42.Nm fetchPut , 43.Nm fetchStat , 44.Nm fetchList , 45.Nm fetchXGetFile , 46.Nm fetchGetFile , 47.Nm fetchPutFile , 48.Nm fetchStatFile , 49.Nm fetchListFile , 50.Nm fetchXGetHTTP , 51.Nm fetchGetHTTP , 52.Nm fetchPutHTTP , 53.Nm fetchStatHTTP , 54.Nm fetchListHTTP , 55.Nm fetchXGetFTP , 56.Nm fetchGetFTP , 57.Nm fetchPutFTP , 58.Nm fetchStatFTP , 59.Nm fetchListFTP 60.Nd file transfer functions 61.Sh LIBRARY 62.Lb libfetch 63.Sh SYNOPSIS 64.In sys/param.h 65.In stdio.h 66.In fetch.h 67.Ft struct url * 68.Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd" 69.Ft struct url * 70.Fn fetchParseURL "const char *URL" 71.Ft void 72.Fn fetchFreeURL "struct url *u" 73.Ft FILE * 74.Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags" 75.Ft FILE * 76.Fn fetchGetURL "const char *URL" "const char *flags" 77.Ft FILE * 78.Fn fetchPutURL "const char *URL" "const char *flags" 79.Ft int 80.Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags" 81.Ft struct url_ent * 82.Fn fetchListURL "const char *URL" "const char *flags" 83.Ft FILE * 84.Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags" 85.Ft FILE * 86.Fn fetchGet "struct url *u" "const char *flags" 87.Ft FILE * 88.Fn fetchPut "struct url *u" "const char *flags" 89.Ft int 90.Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags" 91.Ft struct url_ent * 92.Fn fetchList "struct url *u" "const char *flags" 93.Ft FILE * 94.Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags" 95.Ft FILE * 96.Fn fetchGetFile "struct url *u" "const char *flags" 97.Ft FILE * 98.Fn fetchPutFile "struct url *u" "const char *flags" 99.Ft int 100.Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags" 101.Ft struct url_ent * 102.Fn fetchListFile "struct url *u" "const char *flags" 103.Ft FILE * 104.Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags" 105.Ft FILE * 106.Fn fetchGetHTTP "struct url *u" "const char *flags" 107.Ft FILE * 108.Fn fetchPutHTTP "struct url *u" "const char *flags" 109.Ft int 110.Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags" 111.Ft struct url_ent * 112.Fn fetchListHTTP "struct url *u" "const char *flags" 113.Ft FILE * 114.Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags" 115.Ft FILE * 116.Fn fetchGetFTP "struct url *u" "const char *flags" 117.Ft FILE * 118.Fn fetchPutFTP "struct url *u" "const char *flags" 119.Ft int 120.Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags" 121.Ft struct url_ent * 122.Fn fetchListFTP "struct url *u" "const char *flags" 123.Sh DESCRIPTION 124These functions implement a high-level library for retrieving and 125uploading files using Uniform Resource Locators (URLs). 126.Pp 127.Fn fetchParseURL 128takes a URL in the form of a null-terminated string and splits it into 129its components function according to the Common Internet Scheme Syntax 130detailed in RFC 1738. 131A regular expression which produces this syntax is: 132.Bd -literal 133 <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? 134.Ed 135.Pp 136If the URL does not seem to begin with a scheme name, the following 137syntax is assumed: 138.Bd -literal 139 ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? 140.Ed 141.Pp 142Note that some components of the URL are not necessarily relevant to 143all URL schemes. 144For instance, the file scheme only needs the <scheme> and <document> 145components. 146.Pp 147.Fn fetchMakeURL 148and 149.Fn fetchParseURL 150return a pointer to a 151.Vt url 152structure, which is defined as follows in 153.In fetch.h : 154.Bd -literal 155#define URL_SCHEMELEN 16 156#define URL_USERLEN 256 157#define URL_PWDLEN 256 158 159struct url { 160 char scheme[URL_SCHEMELEN+1]; 161 char user[URL_USERLEN+1]; 162 char pwd[URL_PWDLEN+1]; 163 char host[MAXHOSTNAMELEN+1]; 164 int port; 165 char *doc; 166 off_t offset; 167 size_t length; 168 time_t ims_time; 169}; 170.Ed 171.Pp 172The 173.Va ims_time 174field stores the time value for 175.Li If-Modified-Since 176HTTP requests. 177.Pp 178The pointer returned by 179.Fn fetchMakeURL 180or 181.Fn fetchParseURL 182should be freed using 183.Fn fetchFreeURL . 184.Pp 185.Fn fetchXGetURL , 186.Fn fetchGetURL , 187and 188.Fn fetchPutURL 189constitute the recommended interface to the 190.Nm fetch 191library. 192They examine the URL passed to them to determine the transfer 193method, and call the appropriate lower-level functions to perform the 194actual transfer. 195.Fn fetchXGetURL 196also returns the remote document's metadata in the 197.Vt url_stat 198structure pointed to by the 199.Fa us 200argument. 201.Pp 202The 203.Fa flags 204argument is a string of characters which specify transfer options. 205The 206meaning of the individual flags is scheme-dependent, and is detailed 207in the appropriate section below. 208.Pp 209.Fn fetchStatURL 210attempts to obtain the requested document's metadata and fill in the 211structure pointed to by its second argument. 212The 213.Vt url_stat 214structure is defined as follows in 215.In fetch.h : 216.Bd -literal 217struct url_stat { 218 off_t size; 219 time_t atime; 220 time_t mtime; 221}; 222.Ed 223.Pp 224If the size could not be obtained from the server, the 225.Fa size 226field is set to -1. 227If the modification time could not be obtained from the server, the 228.Fa mtime 229field is set to the epoch. 230If the access time could not be obtained from the server, the 231.Fa atime 232field is set to the modification time. 233.Pp 234.Fn fetchListURL 235attempts to list the contents of the directory pointed to by the URL 236provided. 237If successful, it returns a malloced array of 238.Vt url_ent 239structures. 240The 241.Vt url_ent 242structure is defined as follows in 243.In fetch.h : 244.Bd -literal 245struct url_ent { 246 char name[PATH_MAX]; 247 struct url_stat stat; 248}; 249.Ed 250.Pp 251The list is terminated by an entry with an empty name. 252.Pp 253The pointer returned by 254.Fn fetchListURL 255should be freed using 256.Fn free . 257.Pp 258.Fn fetchXGet , 259.Fn fetchGet , 260.Fn fetchPut 261and 262.Fn fetchStat 263are similar to 264.Fn fetchXGetURL , 265.Fn fetchGetURL , 266.Fn fetchPutURL 267and 268.Fn fetchStatURL , 269except that they expect a pre-parsed URL in the form of a pointer to 270a 271.Vt struct url 272rather than a string. 273.Pp 274All of the 275.Fn fetchXGetXXX , 276.Fn fetchGetXXX 277and 278.Fn fetchPutXXX 279functions return a pointer to a stream which can be used to read or 280write data from or to the requested document, respectively. 281Note that 282although the implementation details of the individual access methods 283vary, it can generally be assumed that a stream returned by one of the 284.Fn fetchXGetXXX 285or 286.Fn fetchGetXXX 287functions is read-only, and that a stream returned by one of the 288.Fn fetchPutXXX 289functions is write-only. 290.Sh FILE SCHEME 291.Fn fetchXGetFile , 292.Fn fetchGetFile 293and 294.Fn fetchPutFile 295provide access to documents which are files in a locally mounted file 296system. 297Only the <document> component of the URL is used. 298.Pp 299.Fn fetchXGetFile 300and 301.Fn fetchGetFile 302do not accept any flags. 303.Pp 304.Fn fetchPutFile 305accepts the 306.Ql a 307(append to file) flag. 308If that flag is specified, the data written to 309the stream returned by 310.Fn fetchPutFile 311will be appended to the previous contents of the file, instead of 312replacing them. 313.Sh FTP SCHEME 314.Fn fetchXGetFTP , 315.Fn fetchGetFTP 316and 317.Fn fetchPutFTP 318implement the FTP protocol as described in RFC 959. 319.Pp 320If the 321.Ql P 322(not passive) flag is specified, an active (rather than passive) 323connection will be attempted. 324.Pp 325The 326.Ql p 327flag is supported for compatibility with earlier versions where active 328connections were the default. 329It has precedence over the 330.Ql P 331flag, so if both are specified, 332.Nm 333will use a passive connection. 334.Pp 335If the 336.Ql l 337(low) flag is specified, data sockets will be allocated in the low (or 338default) port range instead of the high port range (see 339.Xr ip 4 ) . 340.Pp 341If the 342.Ql d 343(direct) flag is specified, 344.Fn fetchXGetFTP , 345.Fn fetchGetFTP 346and 347.Fn fetchPutFTP 348will use a direct connection even if a proxy server is defined. 349.Pp 350If no user name or password is given, the 351.Nm fetch 352library will attempt an anonymous login, with user name "anonymous" 353and password "anonymous@<hostname>". 354.Sh HTTP SCHEME 355The 356.Fn fetchXGetHTTP , 357.Fn fetchGetHTTP 358and 359.Fn fetchPutHTTP 360functions implement the HTTP/1.1 protocol. 361With a little luck, there is 362even a chance that they comply with RFC 2616 and RFC 2617. 363.Pp 364If the 365.Ql d 366(direct) flag is specified, 367.Fn fetchXGetHTTP , 368.Fn fetchGetHTTP 369and 370.Fn fetchPutHTTP 371will use a direct connection even if a proxy server is defined. 372.Pp 373If the 374.Ql i 375(if-modified-since) flag is specified, and 376the 377.Va ims_time 378field is set in 379.Vt "struct url" , 380then 381.Fn fetchXGetHTTP 382and 383.Fn fetchGetHTTP 384will send a conditional 385.Li If-Modified-Since 386HTTP header to only fetch the content if it is newer than 387.Va ims_time . 388.Pp 389Since there seems to be no good way of implementing the HTTP PUT 390method in a manner consistent with the rest of the 391.Nm fetch 392library, 393.Fn fetchPutHTTP 394is currently unimplemented. 395.Sh AUTHENTICATION 396Apart from setting the appropriate environment variables and 397specifying the user name and password in the URL or the 398.Vt struct url , 399the calling program has the option of defining an authentication 400function with the following prototype: 401.Pp 402.Ft int 403.Fn myAuthMethod "struct url *u" 404.Pp 405The callback function should fill in the 406.Fa user 407and 408.Fa pwd 409fields in the provided 410.Vt struct url 411and return 0 on success, or any other value to indicate failure. 412.Pp 413To register the authentication callback, simply set 414.Va fetchAuthMethod 415to point at it. 416The callback will be used whenever a site requires authentication and 417the appropriate environment variables are not set. 418.Pp 419This interface is experimental and may be subject to change. 420.Sh RETURN VALUES 421.Fn fetchParseURL 422returns a pointer to a 423.Vt struct url 424containing the individual components of the URL. 425If it is 426unable to allocate memory, or the URL is syntactically incorrect, 427.Fn fetchParseURL 428returns a NULL pointer. 429.Pp 430The 431.Fn fetchStat 432functions return 0 on success and -1 on failure. 433.Pp 434All other functions return a stream pointer which may be used to 435access the requested document, or NULL if an error occurred. 436.Pp 437The following error codes are defined in 438.In fetch.h : 439.Bl -tag -width 18n 440.It Bq Er FETCH_ABORT 441Operation aborted 442.It Bq Er FETCH_AUTH 443Authentication failed 444.It Bq Er FETCH_DOWN 445Service unavailable 446.It Bq Er FETCH_EXISTS 447File exists 448.It Bq Er FETCH_FULL 449File system full 450.It Bq Er FETCH_INFO 451Informational response 452.It Bq Er FETCH_MEMORY 453Insufficient memory 454.It Bq Er FETCH_MOVED 455File has moved 456.It Bq Er FETCH_NETWORK 457Network error 458.It Bq Er FETCH_OK 459No error 460.It Bq Er FETCH_PROTO 461Protocol error 462.It Bq Er FETCH_RESOLV 463Resolver error 464.It Bq Er FETCH_SERVER 465Server error 466.It Bq Er FETCH_TEMP 467Temporary error 468.It Bq Er FETCH_TIMEOUT 469Operation timed out 470.It Bq Er FETCH_UNAVAIL 471File is not available 472.It Bq Er FETCH_UNKNOWN 473Unknown error 474.It Bq Er FETCH_URL 475Invalid URL 476.El 477.Pp 478The accompanying error message includes a protocol-specific error code 479and message, e.g.\& "File is not available (404 Not Found)" 480.Sh ENVIRONMENT 481.Bl -tag -width ".Ev FETCH_BIND_ADDRESS" 482.It Ev FETCH_BIND_ADDRESS 483Specifies a hostname or IP address to which sockets used for outgoing 484connections will be bound. 485.It Ev FTP_LOGIN 486Default FTP login if none was provided in the URL. 487.It Ev FTP_PASSIVE_MODE 488If set to 489.Ql no , 490forces the FTP code to use active mode. 491If set to any other value, forces passive mode even if the application 492requested active mode. 493.It Ev FTP_PASSWORD 494Default FTP password if the remote server requests one and none was 495provided in the URL. 496.It Ev FTP_PROXY 497URL of the proxy to use for FTP requests. 498The document part is ignored. 499FTP and HTTP proxies are supported; if no scheme is specified, FTP is 500assumed. 501If the proxy is an FTP proxy, 502.Nm libfetch 503will send 504.Ql user@host 505as user name to the proxy, where 506.Ql user 507is the real user name, and 508.Ql host 509is the name of the FTP server. 510.Pp 511If this variable is set to an empty string, no proxy will be used for 512FTP requests, even if the 513.Ev HTTP_PROXY 514variable is set. 515.It Ev ftp_proxy 516Same as 517.Ev FTP_PROXY , 518for compatibility. 519.It Ev HTTP_AUTH 520Specifies HTTP authorization parameters as a colon-separated list of 521items. 522The first and second item are the authorization scheme and realm 523respectively; further items are scheme-dependent. 524Currently, only basic authorization is supported. 525.Pp 526Basic authorization requires two parameters: the user name and 527password, in that order. 528.Pp 529This variable is only used if the server requires authorization and 530no user name or password was specified in the URL. 531.It Ev HTTP_PROXY 532URL of the proxy to use for HTTP requests. 533The document part is ignored. 534Only HTTP proxies are supported for HTTP requests. 535If no port number is specified, the default is 3128. 536.Pp 537Note that this proxy will also be used for FTP documents, unless the 538.Ev FTP_PROXY 539variable is set. 540.It Ev http_proxy 541Same as 542.Ev HTTP_PROXY , 543for compatibility. 544.It Ev HTTP_PROXY_AUTH 545Specifies authorization parameters for the HTTP proxy in the same 546format as the 547.Ev HTTP_AUTH 548variable. 549.Pp 550This variable is used if and only if connected to an HTTP proxy, and 551is ignored if a user and/or a password were specified in the proxy 552URL. 553.It Ev HTTP_REFERER 554Specifies the referrer URL to use for HTTP requests. 555If set to 556.Dq auto , 557the document URL will be used as referrer URL. 558.It Ev HTTP_USER_AGENT 559Specifies the User-Agent string to use for HTTP requests. 560This can be useful when working with HTTP origin or proxy servers that 561differentiate between user agents. 562.It Ev NETRC 563Specifies a file to use instead of 564.Pa ~/.netrc 565to look up login names and passwords for FTP sites. 566See 567.Xr ftp 1 568for a description of the file format. 569This feature is experimental. 570.It Ev NO_PROXY 571Either a single asterisk, which disables the use of proxies 572altogether, or a comma- or whitespace-separated list of hosts for 573which proxies should not be used. 574.It Ev no_proxy 575Same as 576.Ev NO_PROXY , 577for compatibility. 578.El 579.Sh EXAMPLES 580To access a proxy server on 581.Pa proxy.example.com 582port 8080, set the 583.Ev HTTP_PROXY 584environment variable in a manner similar to this: 585.Pp 586.Dl HTTP_PROXY=http://proxy.example.com:8080 587.Pp 588If the proxy server requires authentication, there are 589two options available for passing the authentication data. 590The first method is by using the proxy URL: 591.Pp 592.Dl HTTP_PROXY=http://<user>:<pwd>@proxy.example.com:8080 593.Pp 594The second method is by using the 595.Ev HTTP_PROXY_AUTH 596environment variable: 597.Bd -literal -offset indent 598HTTP_PROXY=http://proxy.example.com:8080 599HTTP_PROXY_AUTH=basic:*:<user>:<pwd> 600.Ed 601.Pp 602To disable the use of a proxy for an HTTP server running on the local 603host, define 604.Ev NO_PROXY 605as follows: 606.Bd -literal -offset indent 607NO_PROXY=localhost,127.0.0.1 608.Ed 609.Sh SEE ALSO 610.Xr fetch 1 , 611.Xr ftpio 3 , 612.Xr ip 4 613.Rs 614.%A J. Postel 615.%A J. K. Reynolds 616.%D October 1985 617.%B File Transfer Protocol 618.%O RFC 959 619.Re 620.Rs 621.%A P. Deutsch 622.%A A. Emtage 623.%A A. Marine. 624.%D May 1994 625.%T How to Use Anonymous FTP 626.%O RFC 1635 627.Re 628.Rs 629.%A T. Berners-Lee 630.%A L. Masinter 631.%A M. McCahill 632.%D December 1994 633.%T Uniform Resource Locators (URL) 634.%O RFC 1738 635.Re 636.Rs 637.%A R. Fielding 638.%A J. Gettys 639.%A J. Mogul 640.%A H. Frystyk 641.%A L. Masinter 642.%A P. Leach 643.%A T. Berners-Lee 644.%D January 1999 645.%B Hypertext Transfer Protocol -- HTTP/1.1 646.%O RFC 2616 647.Re 648.Rs 649.%A J. Franks 650.%A P. Hallam-Baker 651.%A J. Hostetler 652.%A S. Lawrence 653.%A P. Leach 654.%A A. Luotonen 655.%A L. Stewart 656.%D June 1999 657.%B HTTP Authentication: Basic and Digest Access Authentication 658.%O RFC 2617 659.Re 660.Sh HISTORY 661The 662.Nm fetch 663library first appeared in 664.Fx 3.0 . 665.Sh AUTHORS 666.An -nosplit 667The 668.Nm fetch 669library was mostly written by 670.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org 671with numerous suggestions from 672.An Jordan K. Hubbard Aq jkh@FreeBSD.org , 673.An Eugene Skepner Aq eu@qub.com 674and other 675.Fx 676developers. 677It replaces the older 678.Nm ftpio 679library written by 680.An Poul-Henning Kamp Aq phk@FreeBSD.org 681and 682.An Jordan K. Hubbard Aq jkh@FreeBSD.org . 683.Pp 684This manual page was written by 685.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org . 686.Sh BUGS 687Some parts of the library are not yet implemented. 688The most notable 689examples of this are 690.Fn fetchPutHTTP , 691.Fn fetchListHTTP , 692.Fn fetchListFTP 693and FTP proxy support. 694.Pp 695There is no way to select a proxy at run-time other than setting the 696.Ev HTTP_PROXY 697or 698.Ev FTP_PROXY 699environment variables as appropriate. 700.Pp 701.Nm libfetch 702does not understand or obey 305 (Use Proxy) replies. 703.Pp 704Error numbers are unique only within a certain context; the error 705codes used for FTP and HTTP overlap, as do those used for resolver and 706system errors. 707For instance, error code 202 means "Command not 708implemented, superfluous at this site" in an FTP context and 709"Accepted" in an HTTP context. 710.Pp 711.Fn fetchStatFTP 712does not check that the result of an MDTM command is a valid date. 713.Pp 714The man page is incomplete, poorly written and produces badly 715formatted text. 716.Pp 717The error reporting mechanism is unsatisfactory. 718.Pp 719Some parts of the code are not fully reentrant. 720