freebsd-skq/contrib/mdocml/man.cgi.3

.\"	$Id: man.cgi.3,v 1.4 2017/03/15 13:18:53 schwarze Exp $
.\"
.\" Copyright (c) 2016, 2017 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: March 15 2017 $
.Dt MAN.CGI 3
.Os
.Sh NAME
.Nm man.cgi
.Nd internals of the CGI program to search and display manual pages
.Sh DESCRIPTION
The source code of
.Xr man.cgi 8
is organized in four levels:
.Pp
.Bl -enum -compact
.It
.Sx Top level
.It
.Sx Page generators
.It
.Sx Result generators
.It
.Sx Utility routines
.El
.Ss Top level
The top level of
.Xr man.cgi 8
consists of the
.Fn main
program and a few parser routines.
.Bl -tag -width 1n
.It Ft int Fn main void
The main program
.Bl -dash -compact
.It
limits execution time;
.It
changes to
.Dv MAN_DIR ,
the data directory containing all the manual trees;
.It
calls
.Fn parse_manpath_conf ;
.It
if
.Ev PATH_INFO
is empty, calls
.Fn parse_query_string ;
otherwise,
calls
.Fn parse_path_info ;
.It
validates the manpath and the architecture;
.It
calls the appropriate one among the
.Sx Page generators .
.El
.It Ft void Fn parse_manpath_conf "struct req *req"
Parses and validates
.Pa manpath.conf
and fills
.Va req->p
and
.Va req->psz .
.It Ft void Fn parse_path_info "struct req *req" "const char *path"
Parses and validates
.Ev PATH_INFO ,
clears
.Va req->isquery ,
and fills
.Va req->q .
.It Ft void Fn parse_query_string "struct req *req" "const char *qs"
Parses and validates
.Ev QUERY_STRING ,
sets
.Va req->isquery ,
and fills
.Va req->q .
This function is the only user of the utility functions
.Fn http_decode
and
.Fn set_query_attr .
.El
.Ss Page generators
The purpose of each page generator is to print a complete HTML page,
starting with the HTTP headers and continuing to the page footer.
Before starting HTML output with
.Fn resp_begin_html ,
some page generators do some preparatory work, for example to decide
which page to show.
Each page generator ends with a call to
.Fn resp_end_html .
.Bl -tag -width 1n
.It Ft void Fn pg_show "struct req *req" "const char *fullpath"
This page generator is used when
.Ev PATH_INFO
contains the complete path to a manual page including manpath,
section directory, optional architecture subdirectory, manual name
and section number suffix.
It validates the manpath, changes into it, validate the filename,
and then calls
.Fn resp_begin_html ,
.Fn resp_searchform ,
.Fn resp_show ,
and
.Fn resp_end_html
in that order.
.It Ft void Fn pg_search "const struct req *req"
This page generator is used when
.Ev PATH_INFO
contains a search query in short format or when
.Ev PATH_INFO
is empty and a
.Ev QUERY_STRING
is provided.
If possible, requests using
.Ev QUERY_STRING
are redirected to URIs using
.Ev PATH_INFO
by calling
.Fn pg_redirect .
Otherwise, it changes into the manpath and calls
.Xr mansearch 3 .
Depending on the result, it calls either
.Fn pg_noresult
or
.Fn pg_searchres .
.It Ft void Fn pg_redirect "const struct req *req" "const char *name"
This function is special in so far as it does not print an HTML page,
but only an HTTP 303 response with a Location: of the form:
.Sm off
.No http://
.Ar host Ns /
.Op Ar scriptname Ns /
.Op Ar manpath Ns /
.Op Ar arch Ns /
.Fa name
.Op Pf . Ar sec
.Sm on
.It Ft void Fn pg_noresult "const struct req *req" "const char *msg"
This function calls
.Fn resp_begin_html ,
.Fn resp_searchform ,
prints the
.Fa msg
passed to it, and calls
.Fn resp_end_html .
.It Ft void Fn pg_searchres "const struct req *req" "struct manpage *r"\
 "size_t sz"
This function first validates the filenames found.
If
.Ev QUERY_STRING
was used and there is exactly one result,
it writes an HTTP redirect to that result.
Otherwise, it writes an HTML result page beginning with
.Fn resp_begin_html
and
.Fn resp_searchform .
If there is more than one result, it writes a list of links
to all the results.
If it was a
.Xr man 1
rather than an
.Xr apropos 1
query or if there is only one single result, it calls
.Fn resp_show .
Finally, it calls
.Fn resp_end_html .
.It Ft void Fn pg_index "const struct req *req"
This page generator is used when
.Ev PATH_INFO
and
.Ev QUERY_STRING
are both empty.
It calls
.Fn resp_begin_html
and
.Fn resp_searchform ,
writes links to help pages, and calls
.Fn resp_end_html .
.It Ft void Fn pg_error_badrequest "const char *msg"
This page generator is used when
.Fn main
or
.Fn pg_show
detect an invalid URI.
It calls
.Fn resp_begin_html ,
prints the
.Fa msg
provided, and calls
.Fn resp_end_html .
.It Ft void Fn pg_error_internal void
This page generator is used by various functions when errors are
detected in the
.Pa manpath.conf
configuration file, in
.Xr mandoc.db 5
databases, in the
.Xr mandoc 3
parser, in file system permissions, or when setting up timeouts.
It calls
.Fn resp_begin_html ,
prints
.Qq "Internal Server Error" ,
and calls
.Fn resp_end_html .
Before calling
.Fn pg_error_internal ,
call
.Xr warn 3
or
.Xr warnx 3
to log the reason of the error to the
.Xr httpd 8
server log file.
.El
.Ss Result generators
The purpose of result generators is to print a chunk of HTML code.
When they print untrusted strings or characters,
.Fn html_print
and
.Fn html_putchar
are used.
The highest level result generators are:
.Bl -tag -width 1n
.It Ft void Fn resp_begin_html "int code" "const char *msg" "const char *file"
This generator calls
.Fn resp_begin_http
to print the HTTP headers, then prints the HTML header up to the
opening tag of the <body> element, then copies the file
.Pa header.html
to the output, if it exists and is readable.
If
.Fa file
is not
.Dv NULL ,
it is used for the <title> element.
.It Ft void Fn resp_searchform "const struct req *req" "enum focus focus"
This generator prints a search form, filling it with data
from the provided request object.
If the
.Fa focus
argument is
.Dv FOCUS_QUERY ,
it sets the document's autofocus to the query input box.
.It Ft void Fn resp_show "const struct req *req" "const char *file"
This wrapper dispatches to either
.Fn resp_catman
or
.Fn resp_format ,
depending on whether
.Ar file
starts with
.Pa cat
or
.Pa man ,
respectively.
.It Ft void Fn resp_catman "const struct req *req" "const char *file"
This generator translates a preformatted, backspace-encoded manual
page to HTML and prints it to the output.
.It Ft void Fn resp_format "const struct req *req" "const char *file"
This generator formats a manual page on the standard output,
using the functions documented in
.Xr mchars_alloc 3
and
.Xr mandoc 3 .
.It Ft void Fn resp_end_html void
This generator copies the file
.Pa footer.html
to the output, if it exists and is readable,
and closes the <body> and <html> elements.
.El
.Ss Utility routines
These functions take a string and return 1 if it is valid, or 0 otherwise.
.Bl -tag -width 1n
.It Ft int Fn validate_urifrag "const char *frag"
Checks that the string only contains alphanumeric ASCII characters,
dashes, dots, slashes, and underscores.
.It Ft int Fn validate_manpath "const struct req *req" "const char* manpath"
Checks that the string is either
.Qq mandoc
or one of the manpaths configured in
.Pa manpath.conf .
.It Ft int Fn validate_filename "const char *file"
Checks that the string starts with
.Qq man
or
.Qq cat
and does not ascend to parent directories.
.El
.Sh SEE ALSO
.Xr mandoc 3 ,
.Xr mansearch 3 ,
.Xr mchars_alloc 3 ,
.Xr mandoc.db 5 ,
.Xr man.cgi 8