1.\"- 2.\" Copyright (c) 1998-2004 Dag-Erling Co�dan Sm�rgrav 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: fetch.3,v 1.64 2007/12/18 11:03:26 des Exp $ 27.\" $NetBSD: fetch.3,v 1.1.1.7 2009/10/15 12:59:58 joerg Exp $ 28.\" 29.Dd February 4, 2009 30.Dt FETCH 3 31.Os 32.Sh NAME 33.Nm fetchMakeURL , 34.Nm fetchParseURL , 35.Nm fetchCopyURL , 36.Nm fetchFreeURL , 37.Nm fetchXGetURL , 38.Nm fetchGetURL , 39.Nm fetchPutURL , 40.Nm fetchStatURL , 41.Nm fetchListURL , 42.Nm fetchXGet , 43.Nm fetchGet , 44.Nm fetchPut , 45.Nm fetchStat , 46.Nm fetchList , 47.Nm fetchXGetFile , 48.Nm fetchGetFile , 49.Nm fetchPutFile , 50.Nm fetchStatFile , 51.Nm fetchListFile , 52.Nm fetchXGetHTTP , 53.Nm fetchGetHTTP , 54.Nm fetchPutHTTP , 55.Nm fetchStatHTTP , 56.Nm fetchListHTTP , 57.Nm fetchXGetFTP , 58.Nm fetchGetFTP , 59.Nm fetchPutFTP , 60.Nm fetchStatFTP , 61.Nm fetchListFTP 62.Nm fetchInitURLList , 63.Nm fetchFreeURLList , 64.Nm fetchUnquotePath , 65.Nm fetchUnquoteFilename , 66.Nm fetchStringifyURL , 67.Nm fetch 68.Nd file transfer functions 69.Sh LIBRARY 70.Lb libfetch 71.Sh SYNOPSIS 72.In stdio.h 73.In fetch.h 74.Ft struct url * 75.Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd" 76.Ft struct url * 77.Fn fetchParseURL "const char *URL" 78.Ft struct url * 79.Fn fetchCopyURL "const struct url *u" 80.Ft void 81.Fn fetchFreeURL "struct url *u" 82.Ft fetchIO * 83.Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags" 84.Ft fetchIO * 85.Fn fetchGetURL "const char *URL" "const char *flags" 86.Ft fetchIO * 87.Fn fetchPutURL "const char *URL" "const char *flags" 88.Ft int 89.Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags" 90.Ft int 91.Fn fetchListURL "struct url_list *list" "const char *URL" "const char *flags" 92.Ft fetchIO * 93.Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags" 94.Ft fetchIO * 95.Fn fetchGet "struct url *u" "const char *flags" 96.Ft fetchIO * 97.Fn fetchPut "struct url *u" "const char *flags" 98.Ft int 99.Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags" 100.Ft int 101.Fn fetchList "struct url_list *list" "struct url *u" "const char *flags" 102.Ft fetchIO * 103.Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags" 104.Ft fetchIO * 105.Fn fetchGetFile "struct url *u" "const char *flags" 106.Ft fetchIO * 107.Fn fetchPutFile "struct url *u" "const char *flags" 108.Ft int 109.Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags" 110.Ft int 111.Fn fetchListFile "struct url_list *list" "struct url *u" "const char *flags" 112.Ft fetchIO * 113.Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags" 114.Ft fetchIO * 115.Fn fetchGetHTTP "struct url *u" "const char *flags" 116.Ft fetchIO * 117.Fn fetchPutHTTP "struct url *u" "const char *flags" 118.Ft int 119.Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags" 120.Ft int 121.Fn fetchListHTTP "struct url_list *list" "struct url *u" "const char *flags" 122.Ft fetchIO * 123.Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags" 124.Ft fetchIO * 125.Fn fetchGetFTP "struct url *u" "const char *flags" 126.Ft fetchIO * 127.Fn fetchPutFTP "struct url *u" "const char *flags" 128.Ft int 129.Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags" 130.Ft int 131.Fn fetchListFTP "struct url_list *list" "struct url *u" "const char *flags" 132.Ft void 133.Fn fetchInitURLList "struct url_list *ul" 134.Ft int 135.Fn fetchAppendURLList "struct url_list *dst" "const struct url_list *src" 136.Ft void 137.Fn fetchFreeURLList "struct url_list *ul" 138.Ft char * 139.Fn fetchUnquotePath "struct url *u" 140.Ft char * 141.Fn fetchUnquoteFilename "struct url *u" 142.Ft char * 143.Fn fetchStringifyURL "const struct url *u" 144.Sh DESCRIPTION 145These functions implement a high-level library for retrieving and 146uploading files using Uniform Resource Locators (URLs). 147.Pp 148.Fn fetchParseURL 149takes a URL in the form of a null-terminated string and splits it into 150its components function according to the Common Internet Scheme Syntax 151detailed in RFC 1738. 152A regular expression which produces this syntax is: 153.Bd -literal -offset indent 154\*[Lt]scheme\*[Gt]:(//(\*[Lt]user\*[Gt](:\*[Lt]pwd\*[Gt])?@)?\*[Lt]host\*[Gt](:\*[Lt]port\*[Gt])?)?/(\*[Lt]document\*[Gt])? 155.Ed 156.Pp 157If the URL does not seem to begin with a scheme name, it is assumed to be a local path. 158Only absolute path names are accepted. 159.Pp 160Note that some components of the URL are not necessarily relevant to 161all URL schemes. 162For instance, the file scheme only needs the 163.Aq scheme 164and 165.Aq document 166components. 167.Fn fetchParseURL 168quotes any unsafe character in the URL automatically. 169This is not done by 170.Fn fetchMakeURL . 171.Fn fetchCopyURL 172copies an existing 173.Vt url 174structure. 175.Pp 176.Fn fetchMakeURL , 177.Fn fetchParseURL , 178and 179.Fn fetchCopyURL 180return a pointer to a 181.Vt url 182structure, which is defined as follows in 183.In fetch.h : 184.Bd -literal 185#define URL_SCHEMELEN 16 186#define URL_USERLEN 256 187#define URL_PWDLEN 256 188#define URL_HOSTLEN 255 189 190struct url { 191 char scheme[URL_SCHEMELEN + 1]; 192 char user[URL_USERLEN + 1]; 193 char pwd[URL_PWDLEN + 1]; 194 char host[URL_HOSTLEN + 1]; 195 int port; 196 char *doc; 197 off_t offset; 198 size_t length; 199 time_t last_modified; 200}; 201.Ed 202.Pp 203The pointer returned by 204.Fn fetchMakeURL , 205.Fn fetchCopyURL , 206and 207.Fn fetchParseURL 208should be freed using 209.Fn fetchFreeURL . 210The size of 211.Vt struct URL 212is not part of the ABI. 213.Pp 214.Fn fetchXGetURL , 215.Fn fetchGetURL , 216and 217.Fn fetchPutURL 218constitute the recommended interface to the 219.Nm fetch 220library. 221They examine the URL passed to them to determine the transfer 222method, and call the appropriate lower-level functions to perform the 223actual transfer. 224.Fn fetchXGetURL 225also returns the remote document's metadata in the 226.Vt url_stat 227structure pointed to by the 228.Fa us 229argument. 230.Pp 231The 232.Fa flags 233argument is a string of characters which specify transfer options. 234The 235meaning of the individual flags is scheme-dependent, and is detailed 236in the appropriate section below. 237.Pp 238.Fn fetchStatURL 239attempts to obtain the requested document's metadata and fill in the 240structure pointed to by its second argument. 241The 242.Vt url_stat 243structure is defined as follows in 244.In fetch.h : 245.Bd -literal 246struct url_stat { 247 off_t size; 248 time_t atime; 249 time_t mtime; 250}; 251.Ed 252.Pp 253If the size could not be obtained from the server, the 254.Fa size 255field is set to \-1. 256If the modification time could not be obtained from the server, the 257.Fa mtime 258field is set to the epoch. 259If the access time could not be obtained from the server, the 260.Fa atime 261field is set to the modification time. 262.Pp 263.Fn fetchListURL 264attempts to list the contents of the directory pointed to by the URL provided. 265The pattern can be a simple glob-like expression as hint. 266Callers should not depend on the server to filter names. 267If successful, it appends the list of entries to the 268.Vt url_list 269structure. 270The 271.Vt url_list 272structure is defined as follows in 273.In fetch.h : 274.Bd -literal 275struct url_list { 276 size_t length; 277 size_t alloc_size; 278 struct url *urls; 279}; 280.Ed 281.Pp 282The list should be initialized by calling 283.Fn fetchInitURLList 284and the entries be freed by calling 285.Fn fetchFreeURLList . 286The function 287.Fn fetchAppendURLList 288can be used to append one URL lists to another. 289If the 290.Ql c 291(cache result) flag is specified, the library is allowed to internally 292cache the result. 293.Pp 294.Fn fetchStringifyURL 295returns the URL as string. 296.Fn fetchUnquotePath 297returns the path name part of the URL with any quoting undone. 298Query arguments and fragment identifiers are not included. 299.Fn fetchUnquoteFilename 300returns the last component of the path name as returned by 301.Fn fetchUnquotePath . 302.Fn fetchStringifyURL , 303.Fn fetchUnquotePath , 304and 305.Fn fetchUnquoteFilename 306return a string that should be deallocated with 307.Fn free 308after use. 309.Pp 310.Fn fetchXGet , 311.Fn fetchGet , 312.Fn fetchPut , 313and 314.Fn fetchStat 315are similar to 316.Fn fetchXGetURL , 317.Fn fetchGetURL , 318.Fn fetchPutURL , 319and 320.Fn fetchStatURL , 321except that they expect a pre-parsed URL in the form of a pointer to 322a 323.Vt struct url 324rather than a string. 325.Pp 326All of the 327.Fn fetchXGetXXX , 328.Fn fetchGetXXX , 329and 330.Fn fetchPutXXX 331functions return a pointer to a stream which can be used to read or 332write data from or to the requested document, respectively. 333Note that 334although the implementation details of the individual access methods 335vary, it can generally be assumed that a stream returned by one of the 336.Fn fetchXGetXXX 337or 338.Fn fetchGetXXX 339functions is read-only, and that a stream returned by one of the 340.Fn fetchPutXXX 341functions is write-only. 342.Sh PROTOCOL INDEPENDENT FLAGS 343If the 344.Ql i 345(if-modified-since) flag is specified, the library will try to fetch 346the content only if it is newer than 347.Va last_modified . 348For HTTP an 349.Li If-Modified-Since 350HTTP header is sent. 351For FTP a 352.Li MTDM 353command is sent first and compared locally. 354For FILE the source file is compared. 355.Sh FILE SCHEME 356.Fn fetchXGetFile , 357.Fn fetchGetFile , 358and 359.Fn fetchPutFile 360provide access to documents which are files in a locally mounted file 361system. 362Only the 363.Aq document 364component of the URL is used. 365.Pp 366.Fn fetchXGetFile 367and 368.Fn fetchGetFile 369do not accept any flags. 370.Pp 371.Fn fetchPutFile 372accepts the 373.Ql a 374(append to file) flag. 375If that flag is specified, the data written to 376the stream returned by 377.Fn fetchPutFile 378will be appended to the previous contents of the file, instead of 379replacing them. 380.Sh FTP SCHEME 381.Fn fetchXGetFTP , 382.Fn fetchGetFTP , 383and 384.Fn fetchPutFTP 385implement the FTP protocol as described in RFC 959. 386.Pp 387By default 388.Nm libfetch 389will attempt to use passive mode first and only fallback to active mode 390if the server reports a syntax error. 391If the 392.Ql a 393(active) flag is specified, a passive connection is not tried and active mode 394is used directly. 395.Pp 396If the 397.Ql l 398(low) flag is specified, data sockets will be allocated in the low (or 399default) port range instead of the high port range (see 400.Xr ip 4 ) . 401.Pp 402If the 403.Ql d 404(direct) flag is specified, 405.Fn fetchXGetFTP , 406.Fn fetchGetFTP , 407and 408.Fn fetchPutFTP 409will use a direct connection even if a proxy server is defined. 410.Pp 411If no user name or password is given, the 412.Nm fetch 413library will attempt an anonymous login, with user name "anonymous" 414and password "anonymous@\*[Lt]hostname\*[Gt]". 415.Sh HTTP SCHEME 416The 417.Fn fetchXGetHTTP , 418.Fn fetchGetHTTP , 419and 420.Fn fetchPutHTTP 421functions implement the HTTP/1.1 protocol. 422With a little luck, there is 423even a chance that they comply with RFC 2616 and RFC 2617. 424.Pp 425If the 426.Ql d 427(direct) flag is specified, 428.Fn fetchXGetHTTP , 429.Fn fetchGetHTTP , 430and 431.Fn fetchPutHTTP 432will use a direct connection even if a proxy server is defined. 433.Pp 434Since there seems to be no good way of implementing the HTTP PUT 435method in a manner consistent with the rest of the 436.Nm fetch 437library, 438.Fn fetchPutHTTP 439is currently unimplemented. 440.Sh AUTHENTICATION 441Apart from setting the appropriate environment variables and 442specifying the user name and password in the URL or the 443.Vt struct url , 444the calling program has the option of defining an authentication 445function with the following prototype: 446.Pp 447.Ft int 448.Fn myAuthMethod "struct url *u" 449.Pp 450The callback function should fill in the 451.Fa user 452and 453.Fa pwd 454fields in the provided 455.Vt struct url 456and return 0 on success, or any other value to indicate failure. 457.Pp 458To register the authentication callback, simply set 459.Va fetchAuthMethod 460to point at it. 461The callback will be used whenever a site requires authentication and 462the appropriate environment variables are not set. 463.Pp 464This interface is experimental and may be subject to change. 465.Sh RETURN VALUES 466.Fn fetchParseURL 467returns a pointer to a 468.Vt struct url 469containing the individual components of the URL. 470If it is 471unable to allocate memory, or the URL is syntactically incorrect, 472.Fn fetchParseURL 473returns a 474.Dv NULL 475pointer. 476.Pp 477The 478.Fn fetchStat 479functions return 0 on success and \-1 on failure. 480.Pp 481All other functions return a stream pointer which may be used to 482access the requested document, or 483.Dv NULL 484if an error occurred. 485.Pp 486The following error codes are defined in 487.In fetch.h : 488.Bl -tag -width 18n 489.It Bq Er FETCH_ABORT 490Operation aborted 491.It Bq Er FETCH_AUTH 492Authentication failed 493.It Bq Er FETCH_DOWN 494Service unavailable 495.It Bq Er FETCH_EXISTS 496File exists 497.It Bq Er FETCH_FULL 498File system full 499.It Bq Er FETCH_INFO 500Informational response 501.It Bq Er FETCH_MEMORY 502Insufficient memory 503.It Bq Er FETCH_MOVED 504File has moved 505.It Bq Er FETCH_NETWORK 506Network error 507.It Bq Er FETCH_OK 508No error 509.It Bq Er FETCH_PROTO 510Protocol error 511.It Bq Er FETCH_RESOLV 512Resolver error 513.It Bq Er FETCH_SERVER 514Server error 515.It Bq Er FETCH_TEMP 516Temporary error 517.It Bq Er FETCH_TIMEOUT 518Operation timed out 519.It Bq Er FETCH_UNAVAIL 520File is not available 521.It Bq Er FETCH_UNKNOWN 522Unknown error 523.It Bq Er FETCH_URL 524Invalid URL 525.El 526.Pp 527The accompanying error message includes a protocol-specific error code 528and message, e.g.\& "File is not available (404 Not Found)" 529.Sh ENVIRONMENT 530.Bl -tag -width ".Ev FETCH_BIND_ADDRESS" 531.It Ev FETCH_BIND_ADDRESS 532Specifies a host name or IP address to which sockets used for outgoing 533connections will be bound. 534.It Ev FTP_LOGIN 535Default FTP login if none was provided in the URL. 536.It Ev FTP_PASSIVE_MODE 537If set to anything but 538.Ql no , 539forces the FTP code to use passive mode. 540.It Ev FTP_PASSWORD 541Default FTP password if the remote server requests one and none was 542provided in the URL. 543.It Ev FTP_PROXY 544URL of the proxy to use for FTP requests. 545The document part is ignored. 546FTP and HTTP proxies are supported; if no scheme is specified, FTP is 547assumed. 548If the proxy is an FTP proxy, 549.Nm libfetch 550will send 551.Ql user@host 552as user name to the proxy, where 553.Ql user 554is the real user name, and 555.Ql host 556is the name of the FTP server. 557.Pp 558If this variable is set to an empty string, no proxy will be used for 559FTP requests, even if the 560.Ev HTTP_PROXY 561variable is set. 562.It Ev ftp_proxy 563Same as 564.Ev FTP_PROXY , 565for compatibility. 566.It Ev HTTP_AUTH 567Specifies HTTP authorization parameters as a colon-separated list of 568items. 569The first and second item are the authorization scheme and realm 570respectively; further items are scheme-dependent. 571Currently, only basic authorization is supported. 572.Pp 573Basic authorization requires two parameters: the user name and 574password, in that order. 575.Pp 576This variable is only used if the server requires authorization and 577no user name or password was specified in the URL. 578.It Ev HTTP_PROXY 579URL of the proxy to use for HTTP requests. 580The document part is ignored. 581Only HTTP proxies are supported for HTTP requests. 582If no port number is specified, the default is 3128. 583.Pp 584Note that this proxy will also be used for FTP documents, unless the 585.Ev FTP_PROXY 586variable is set. 587.It Ev http_proxy 588Same as 589.Ev HTTP_PROXY , 590for compatibility. 591.It Ev HTTP_PROXY_AUTH 592Specifies authorization parameters for the HTTP proxy in the same 593format as the 594.Ev HTTP_AUTH 595variable. 596.Pp 597This variable is used if and only if connected to an HTTP proxy, and 598is ignored if a user and/or a password were specified in the proxy 599URL. 600.It Ev HTTP_REFERER 601Specifies the referrer URL to use for HTTP requests. 602If set to 603.Dq auto , 604the document URL will be used as referrer URL. 605.It Ev HTTP_USER_AGENT 606Specifies the User-Agent string to use for HTTP requests. 607This can be useful when working with HTTP origin or proxy servers that 608differentiate between user agents. 609.It Ev NETRC 610Specifies a file to use instead of 611.Pa ~/.netrc 612to look up login names and passwords for FTP sites. 613See 614.Xr ftp 1 615for a description of the file format. 616This feature is experimental. 617.It Ev NO_PROXY 618Either a single asterisk, which disables the use of proxies 619altogether, or a comma- or whitespace-separated list of hosts for 620which proxies should not be used. 621.It Ev no_proxy 622Same as 623.Ev NO_PROXY , 624for compatibility. 625.El 626.Sh EXAMPLES 627To access a proxy server on 628.Pa proxy.example.com 629port 8080, set the 630.Ev HTTP_PROXY 631environment variable in a manner similar to this: 632.Pp 633.Dl HTTP_PROXY=http://proxy.example.com:8080 634.Pp 635If the proxy server requires authentication, there are 636two options available for passing the authentication data. 637The first method is by using the proxy URL: 638.Pp 639.Dl HTTP_PROXY=http://\*[Lt]user\*[Gt]:\*[Lt]pwd\*[Gt]@proxy.example.com:8080 640.Pp 641The second method is by using the 642.Ev HTTP_PROXY_AUTH 643environment variable: 644.Bd -literal -offset indent 645HTTP_PROXY=http://proxy.example.com:8080 646HTTP_PROXY_AUTH=basic:*:\*[Lt]user\*[Gt]:\*[Lt]pwd\*[Gt] 647.Ed 648.Pp 649To disable the use of a proxy for an HTTP server running on the local 650host, define 651.Ev NO_PROXY 652as follows: 653.Bd -literal -offset indent 654NO_PROXY=localhost,127.0.0.1 655.Ed 656.Sh SEE ALSO 657.\" .Xr fetch 1 , 658.\" .Xr ftpio 3 , 659.Xr ftp 1 , 660.Xr ip 4 661.Rs 662.%A J. Postel 663.%A J. K. Reynolds 664.%D October 1985 665.%B File Transfer Protocol 666.%O RFC 959 667.Re 668.Rs 669.%A P. Deutsch 670.%A A. Emtage 671.%A A. Marine 672.%D May 1994 673.%T How to Use Anonymous FTP 674.%O RFC 1635 675.Re 676.Rs 677.%A T. Berners-Lee 678.%A L. Masinter 679.%A M. McCahill 680.%D December 1994 681.%T Uniform Resource Locators (URL) 682.%O RFC 1738 683.Re 684.Rs 685.%A R. Fielding 686.%A J. Gettys 687.%A J. Mogul 688.%A H. Frystyk 689.%A L. Masinter 690.%A P. Leach 691.%A T. Berners-Lee 692.%D January 1999 693.%B Hypertext Transfer Protocol -- HTTP/1.1 694.%O RFC 2616 695.Re 696.Rs 697.%A J. Franks 698.%A P. Hallam-Baker 699.%A J. Hostetler 700.%A S. Lawrence 701.%A P. Leach 702.%A A. Luotonen 703.%A L. Stewart 704.%D June 1999 705.%B HTTP Authentication: Basic and Digest Access Authentication 706.%O RFC 2617 707.Re 708.Sh HISTORY 709The 710.Nm fetch 711library first appeared in 712.Fx 3.0 . 713.Sh AUTHORS 714.An -nosplit 715The 716.Nm fetch 717library was mostly written by 718.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org 719with numerous suggestions from 720.An Jordan K. Hubbard Aq jkh@FreeBSD.org , 721.An Eugene Skepner Aq eu@qub.com 722and other 723.Fx 724developers. 725It replaces the older 726.Nm ftpio 727library written by 728.An Poul-Henning Kamp Aq phk@FreeBSD.org 729and 730.An Jordan K. Hubbard Aq jkh@FreeBSD.org . 731.Pp 732This manual page was written by 733.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org . 734.Sh BUGS 735Some parts of the library are not yet implemented. 736The most notable 737examples of this are 738.Fn fetchPutHTTP 739and FTP proxy support. 740.Pp 741There is no way to select a proxy at run-time other than setting the 742.Ev HTTP_PROXY 743or 744.Ev FTP_PROXY 745environment variables as appropriate. 746.Pp 747.Nm libfetch 748does not understand or obey 305 (Use Proxy) replies. 749.Pp 750Error numbers are unique only within a certain context; the error 751codes used for FTP and HTTP overlap, as do those used for resolver and 752system errors. 753For instance, error code 202 means "Command not 754implemented, superfluous at this site" in an FTP context and 755"Accepted" in an HTTP context. 756.Pp 757.Fn fetchStatFTP 758does not check that the result of an MDTM command is a valid date. 759.Pp 760The man page is incomplete, poorly written and produces badly 761formatted text. 762.Pp 763The error reporting mechanism is unsatisfactory. 764.Pp 765Some parts of the code are not fully reentrant. 766