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| -rw-r--r-- | lib/libfetch/fetch.3 | 668 |
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diff --git a/lib/libfetch/fetch.3 b/lib/libfetch/fetch.3 new file mode 100644 index 00000000..67c29b08 --- /dev/null +++ b/lib/libfetch/fetch.3 @@ -0,0 +1,668 @@ +.\"- +.\" Copyright (c) 1998-2004 Dag-Erling Coïdan Smørgrav +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD: /repoman/r/ncvs/src/lib/libfetch/fetch.3,v 1.61 2005/11/30 04:08:45 tmclaugh Exp $ +.\" +.Dd July 1, 1998 +.Dt FETCH 3 +.Os +.Sh NAME +.Nm fetchMakeURL , +.Nm fetchParseURL , +.Nm fetchFreeURL , +.Nm fetchXGetURL , +.Nm fetchGetURL , +.Nm fetchPutURL , +.Nm fetchStatURL , +.Nm fetchListURL , +.Nm fetchXGet , +.Nm fetchGet , +.Nm fetchPut , +.Nm fetchStat , +.Nm fetchList , +.Nm fetchXGetFile , +.Nm fetchGetFile , +.Nm fetchPutFile , +.Nm fetchStatFile , +.Nm fetchListFile , +.Nm fetchXGetHTTP , +.Nm fetchGetHTTP , +.Nm fetchPutHTTP , +.Nm fetchStatHTTP , +.Nm fetchListHTTP , +.Nm fetchXGetFTP , +.Nm fetchGetFTP , +.Nm fetchPutFTP , +.Nm fetchStatFTP , +.Nm fetchListFTP +.Nd file transfer functions +.Sh LIBRARY +.Lb libfetch +.Sh SYNOPSIS +.In sys/param.h +.In stdio.h +.In fetch.h +.Ft struct url * +.Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd" +.Ft struct url * +.Fn fetchParseURL "const char *URL" +.Ft void +.Fn fetchFreeURL "struct url *u" +.Ft FILE * +.Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags" +.Ft FILE * +.Fn fetchGetURL "const char *URL" "const char *flags" +.Ft FILE * +.Fn fetchPutURL "const char *URL" "const char *flags" +.Ft int +.Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags" +.Ft struct url_ent * +.Fn fetchListURL "const char *URL" "const char *flags" +.Ft FILE * +.Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags" +.Ft FILE * +.Fn fetchGet "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchPut "struct url *u" "const char *flags" +.Ft int +.Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags" +.Ft struct url_ent * +.Fn fetchList "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags" +.Ft FILE * +.Fn fetchGetFile "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchPutFile "struct url *u" "const char *flags" +.Ft int +.Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags" +.Ft struct url_ent * +.Fn fetchListFile "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags" +.Ft FILE * +.Fn fetchGetHTTP "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchPutHTTP "struct url *u" "const char *flags" +.Ft int +.Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags" +.Ft struct url_ent * +.Fn fetchListHTTP "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags" +.Ft FILE * +.Fn fetchGetFTP "struct url *u" "const char *flags" +.Ft FILE * +.Fn fetchPutFTP "struct url *u" "const char *flags" +.Ft int +.Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags" +.Ft struct url_ent * +.Fn fetchListFTP "struct url *u" "const char *flags" +.Sh DESCRIPTION +These functions implement a high-level library for retrieving and +uploading files using Uniform Resource Locators (URLs). +.Pp +.Fn fetchParseURL +takes a URL in the form of a null-terminated string and splits it into +its components function according to the Common Internet Scheme Syntax +detailed in RFC1738. +A regular expression which produces this syntax is: +.Bd -literal + <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? +.Ed +.Pp +If the URL does not seem to begin with a scheme name, the following +syntax is assumed: +.Bd -literal + ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)? +.Ed +.Pp +Note that some components of the URL are not necessarily relevant to +all URL schemes. +For instance, the file scheme only needs the <scheme> and <document> +components. +.Pp +.Fn fetchMakeURL +and +.Fn fetchParseURL +return a pointer to a +.Vt url +structure, which is defined as follows in +.In fetch.h : +.Bd -literal +#define URL_SCHEMELEN 16 +#define URL_USERLEN 256 +#define URL_PWDLEN 256 + +struct url { + char scheme[URL_SCHEMELEN+1]; + char user[URL_USERLEN+1]; + char pwd[URL_PWDLEN+1]; + char host[MAXHOSTNAMELEN+1]; + int port; + char *doc; + off_t offset; + size_t length; +}; +.Ed +.Pp +The pointer returned by +.Fn fetchMakeURL +or +.Fn fetchParseURL +should be freed using +.Fn fetchFreeURL . +.Pp +.Fn fetchXGetURL , +.Fn fetchGetURL , +and +.Fn fetchPutURL +constitute the recommended interface to the +.Nm fetch +library. +They examine the URL passed to them to determine the transfer +method, and call the appropriate lower-level functions to perform the +actual transfer. +.Fn fetchXGetURL +also returns the remote document's metadata in the +.Vt url_stat +structure pointed to by the +.Fa us +argument. +.Pp +The +.Fa flags +argument is a string of characters which specify transfer options. +The +meaning of the individual flags is scheme-dependent, and is detailed +in the appropriate section below. +.Pp +.Fn fetchStatURL +attempts to obtain the requested document's metadata and fill in the +structure pointed to by its second argument. +The +.Vt url_stat +structure is defined as follows in +.In fetch.h : +.Bd -literal +struct url_stat { + off_t size; + time_t atime; + time_t mtime; +}; +.Ed +.Pp +If the size could not be obtained from the server, the +.Fa size +field is set to -1. +If the modification time could not be obtained from the server, the +.Fa mtime +field is set to the epoch. +If the access time could not be obtained from the server, the +.Fa atime +field is set to the modification time. +.Pp +.Fn fetchListURL +attempts to list the contents of the directory pointed to by the URL +provided. +If successful, it returns a malloced array of +.Vt url_ent +structures. +The +.Vt url_ent +structure is defined as follows in +.In fetch.h : +.Bd -literal +struct url_ent { + char name[MAXPATHLEN]; + struct url_stat stat; +}; +.Ed +.Pp +The list is terminated by an entry with an empty name. +.Pp +The pointer returned by +.Fn fetchListURL +should be freed using +.Fn free . +.Pp +.Fn fetchXGet , +.Fn fetchGet , +.Fn fetchPut +and +.Fn fetchStat +are similar to +.Fn fetchXGetURL , +.Fn fetchGetURL , +.Fn fetchPutURL +and +.Fn fetchStatURL , +except that they expect a pre-parsed URL in the form of a pointer to +a +.Vt struct url +rather than a string. +.Pp +All of the +.Fn fetchXGetXXX , +.Fn fetchGetXXX +and +.Fn fetchPutXXX +functions return a pointer to a stream which can be used to read or +write data from or to the requested document, respectively. +Note that +although the implementation details of the individual access methods +vary, it can generally be assumed that a stream returned by one of the +.Fn fetchXGetXXX +or +.Fn fetchGetXXX +functions is read-only, and that a stream returned by one of the +.Fn fetchPutXXX +functions is write-only. +.Sh FILE SCHEME +.Fn fetchXGetFile , +.Fn fetchGetFile +and +.Fn fetchPutFile +provide access to documents which are files in a locally mounted file +system. +Only the <document> component of the URL is used. +.Pp +.Fn fetchXGetFile +and +.Fn fetchGetFile +do not accept any flags. +.Pp +.Fn fetchPutFile +accepts the +.Ql a +(append to file) flag. +If that flag is specified, the data written to +the stream returned by +.Fn fetchPutFile +will be appended to the previous contents of the file, instead of +replacing them. +.Sh FTP SCHEME +.Fn fetchXGetFTP , +.Fn fetchGetFTP +and +.Fn fetchPutFTP +implement the FTP protocol as described in RFC959. +.Pp +If the +.Ql p +(passive) flag is specified, a passive (rather than active) connection +will be attempted. +.Pp +If the +.Ql l +(low) flag is specified, data sockets will be allocated in the low (or +default) port range instead of the high port range (see +.Xr ip 4 ) . +.Pp +If the +.Ql d +(direct) flag is specified, +.Fn fetchXGetFTP , +.Fn fetchGetFTP +and +.Fn fetchPutFTP +will use a direct connection even if a proxy server is defined. +.Pp +If no user name or password is given, the +.Nm fetch +library will attempt an anonymous login, with user name "anonymous" +and password "anonymous@<hostname>". +.Sh HTTP SCHEME +The +.Fn fetchXGetHTTP , +.Fn fetchGetHTTP +and +.Fn fetchPutHTTP +functions implement the HTTP/1.1 protocol. +With a little luck, there is +even a chance that they comply with RFC2616 and RFC2617. +.Pp +If the +.Ql d +(direct) flag is specified, +.Fn fetchXGetHTTP , +.Fn fetchGetHTTP +and +.Fn fetchPutHTTP +will use a direct connection even if a proxy server is defined. +.Pp +Since there seems to be no good way of implementing the HTTP PUT +method in a manner consistent with the rest of the +.Nm fetch +library, +.Fn fetchPutHTTP +is currently unimplemented. +.Sh AUTHENTICATION +Apart from setting the appropriate environment variables and +specifying the user name and password in the URL or the +.Vt struct url , +the calling program has the option of defining an authentication +function with the following prototype: +.Pp +.Ft int +.Fn myAuthMethod "struct url *u" +.Pp +The callback function should fill in the +.Fa user +and +.Fa pwd +fields in the provided +.Vt struct url +and return 0 on success, or any other value to indicate failure. +.Pp +To register the authentication callback, simply set +.Va fetchAuthMethod +to point at it. +The callback will be used whenever a site requires authentication and +the appropriate environment variables are not set. +.Pp +This interface is experimental and may be subject to change. +.Sh RETURN VALUES +.Fn fetchParseURL +returns a pointer to a +.Vt struct url +containing the individual components of the URL. +If it is +unable to allocate memory, or the URL is syntactically incorrect, +.Fn fetchParseURL +returns a NULL pointer. +.Pp +The +.Fn fetchStat +functions return 0 on success and -1 on failure. +.Pp +All other functions return a stream pointer which may be used to +access the requested document, or NULL if an error occurred. +.Pp +The following error codes are defined in +.In fetch.h : +.Bl -tag -width 18n +.It Bq Er FETCH_ABORT +Operation aborted +.It Bq Er FETCH_AUTH +Authentication failed +.It Bq Er FETCH_DOWN +Service unavailable +.It Bq Er FETCH_EXISTS +File exists +.It Bq Er FETCH_FULL +File system full +.It Bq Er FETCH_INFO +Informational response +.It Bq Er FETCH_MEMORY +Insufficient memory +.It Bq Er FETCH_MOVED +File has moved +.It Bq Er FETCH_NETWORK +Network error +.It Bq Er FETCH_OK +No error +.It Bq Er FETCH_PROTO +Protocol error +.It Bq Er FETCH_RESOLV +Resolver error +.It Bq Er FETCH_SERVER +Server error +.It Bq Er FETCH_TEMP +Temporary error +.It Bq Er FETCH_TIMEOUT +Operation timed out +.It Bq Er FETCH_UNAVAIL +File is not available +.It Bq Er FETCH_UNKNOWN +Unknown error +.It Bq Er FETCH_URL +Invalid URL +.El +.Pp +The accompanying error message includes a protocol-specific error code +and message, e.g.\& "File is not available (404 Not Found)" +.Sh ENVIRONMENT +.Bl -tag -width ".Ev FETCH_BIND_ADDRESS" +.It Ev FETCH_BIND_ADDRESS +Specifies a hostname or IP address to which sockets used for outgoing +connections will be bound. +.It Ev FTP_LOGIN +Default FTP login if none was provided in the URL. +.It Ev FTP_PASSIVE_MODE +If set to anything but +.Ql no , +forces the FTP code to use passive mode. +.It Ev FTP_PASSWORD +Default FTP password if the remote server requests one and none was +provided in the URL. +.It Ev FTP_PROXY +URL of the proxy to use for FTP requests. +The document part is ignored. +FTP and HTTP proxies are supported; if no scheme is specified, FTP is +assumed. +If the proxy is an FTP proxy, +.Nm libfetch +will send +.Ql user@host +as user name to the proxy, where +.Ql user +is the real user name, and +.Ql host +is the name of the FTP server. +.Pp +If this variable is set to an empty string, no proxy will be used for +FTP requests, even if the +.Ev HTTP_PROXY +variable is set. +.It Ev ftp_proxy +Same as +.Ev FTP_PROXY , +for compatibility. +.It Ev HTTP_AUTH +Specifies HTTP authorization parameters as a colon-separated list of +items. +The first and second item are the authorization scheme and realm +respectively; further items are scheme-dependent. +Currently, only basic authorization is supported. +.Pp +Basic authorization requires two parameters: the user name and +password, in that order. +.Pp +This variable is only used if the server requires authorization and +no user name or password was specified in the URL. +.It Ev HTTP_PROXY +URL of the proxy to use for HTTP requests. +The document part is ignored. +Only HTTP proxies are supported for HTTP requests. +If no port number is specified, the default is 3128. +.Pp +Note that this proxy will also be used for FTP documents, unless the +.Ev FTP_PROXY +variable is set. +.It Ev http_proxy +Same as +.Ev HTTP_PROXY , +for compatibility. +.It Ev HTTP_PROXY_AUTH +Specifies authorization parameters for the HTTP proxy in the same +format as the +.Ev HTTP_AUTH +variable. +.Pp +This variable is used if and only if connected to an HTTP proxy, and +is ignored if a user and/or a password were specified in the proxy +URL. +.It Ev HTTP_REFERER +Specifies the referrer URL to use for HTTP requests. +If set to +.Dq auto , +the document URL will be used as referrer URL. +.It Ev HTTP_USER_AGENT +Specifies the User-Agent string to use for HTTP requests. +This can be useful when working with HTTP origin or proxy servers that +differentiate between user agents. +.It Ev NETRC +Specifies a file to use instead of +.Pa ~/.netrc +to look up login names and passwords for FTP sites. +See +.Xr ftp 1 +for a description of the file format. +This feature is experimental. +.El +.Sh EXAMPLES +To access a proxy server on +.Pa proxy.example.com +port 8080, set the +.Ev HTTP_PROXY +environment variable in a manner similar to this: +.Pp +.Dl HTTP_PROXY=http://proxy.example.com:8080 +.Pp +If the proxy server requires authentication, there are +two options available for passing the authentication data. +The first method is by using the proxy URL: +.Pp +.Dl HTTP_PROXY=http://<user>:<pwd>@proxy.example.com:8080 +.Pp +The second method is by using the +.Ev HTTP_PROXY_AUTH +environment variable: +.Bd -literal -offset indent +HTTP_PROXY=http://proxy.example.com:8080 +HTTP_PROXY_AUTH=basic:*:<user>:<pwd> +.Ed +.Sh SEE ALSO +.Xr fetch 1 , +.Xr ftpio 3 , +.Xr ip 4 +.Rs +.%A J. Postel +.%A J. K. Reynolds +.%D October 1985 +.%B File Transfer Protocol +.%O RFC959 +.Re +.Rs +.%A P. Deutsch +.%A A. Emtage +.%A A. Marine. +.%D May 1994 +.%T How to Use Anonymous FTP +.%O RFC1635 +.Re +.Rs +.%A T. Berners-Lee +.%A L. Masinter +.%A M. McCahill +.%D December 1994 +.%T Uniform Resource Locators (URL) +.%O RFC1738 +.Re +.Rs +.%A R. Fielding +.%A J. Gettys +.%A J. Mogul +.%A H. Frystyk +.%A L. Masinter +.%A P. Leach +.%A T. Berners-Lee +.%D January 1999 +.%B Hypertext Transfer Protocol -- HTTP/1.1 +.%O RFC2616 +.Re +.Rs +.%A J. Franks +.%A P. Hallam-Baker +.%A J. Hostetler +.%A S. Lawrence +.%A P. Leach +.%A A. Luotonen +.%A L. Stewart +.%D June 1999 +.%B HTTP Authentication: Basic and Digest Access Authentication +.%O RFC2617 +.Re +.Sh HISTORY +The +.Nm fetch +library first appeared in +.Fx 3.0 . +.Sh AUTHORS +.An -nosplit +The +.Nm fetch +library was mostly written by +.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org +with numerous suggestions from +.An Jordan K. Hubbard Aq jkh@FreeBSD.org , +.An Eugene Skepner Aq eu@qub.com +and other +.Fx +developers. +It replaces the older +.Nm ftpio +library written by +.An Poul-Henning Kamp Aq phk@FreeBSD.org +and +.An Jordan K. Hubbard Aq jkh@FreeBSD.org . +.Pp +This manual page was written by +.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org . +.Sh BUGS +Some parts of the library are not yet implemented. +The most notable +examples of this are +.Fn fetchPutHTTP , +.Fn fetchListHTTP , +.Fn fetchListFTP +and FTP proxy support. +.Pp +There is no way to select a proxy at run-time other than setting the +.Ev HTTP_PROXY +or +.Ev FTP_PROXY +environment variables as appropriate. +.Pp +.Nm libfetch +does not understand or obey 305 (Use Proxy) replies. +.Pp +Error numbers are unique only within a certain context; the error +codes used for FTP and HTTP overlap, as do those used for resolver and +system errors. +For instance, error code 202 means "Command not +implemented, superfluous at this site" in an FTP context and +"Accepted" in an HTTP context. +.Pp +.Fn fetchStatFTP +does not check that the result of an MDTM command is a valid date. +.Pp +The man page is incomplete, poorly written and produces badly +formatted text. +.Pp +The error reporting mechanism is unsatisfactory. +.Pp +Some parts of the code are not fully reentrant. |