Copyright (c) 2016, 2017 Ingo Schwarze <schwarze@openbsd.org>
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.Dd 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:
p l -enum -compact t .Sx Top level t .Sx Page generators t .Sx Result generators t .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. l -tag -width 1n t Ft int Fn main void The main program l -dash -compact t limits execution time; t changes to .Dv MAN_DIR , the data directory containing all the manual trees; t calls .Fn parse_manpath_conf ; t if .Ev PATH_INFO is empty, calls .Fn parse_query_string ; otherwise, calls .Fn parse_path_info ; t validates the manpath and the architecture; t calls the appropriate one among the .Sx Page generators . .El t Ft void Fn parse_manpath_conf "struct req *req" Parses and validates
a manpath.conf and fills .Va req->p and .Va req->psz . t 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 . t 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 . l -tag -width 1n t 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. t 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 . t 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 t 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 . t 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 . t 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 . t 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 . t Ft void Fn pg_error_internal void This page generator is used by various functions when errors are detected in the
a 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: l -tag -width 1n t 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
a 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. t 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. t 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
a cat or
a man , respectively. t 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. t 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 . t Ft void Fn resp_end_html void This generator copies the file
a 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. l -tag -width 1n t Ft int Fn validate_urifrag "const char *frag" Checks that the string only contains alphanumeric ASCII characters, dashes, dots, slashes, and underscores. t 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
a manpath.conf . t 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