man.cgi.3

   1 .\"     $Id: man.cgi.3,v 1.3 2017/03/15 10:17:29 schwarze Exp $
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   3 .\" Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
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  17 .Dd $Mdocdate: March 15 2017 $
  18 .Dt MAN.CGI 3
  19 .Os
  20 .Sh NAME
  21 .Nm man.cgi
  22 .Nd internals of the CGI program to search and display manual pages
  23 .Sh DESCRIPTION
  24 The source code of
  25 .Xr man.cgi 8
  26 is organized in four levels:
  27 .Pp
  28 .Bl -enum -compact
  29 .It
  30 .Sx Top level
  31 .It
  32 .Sx Page generators
  33 .It
  34 .Sx Result generators
  35 .It
  36 .Sx Utility routines
  37 .El
  38 .Ss Top level
  39 The top level of
  40 .Xr man.cgi 8
  41 consists of the
  42 .Fn main
  43 program and a few parser routines.
  44 .Bl -tag -width 1n
  45 .It Ft int Fn main void
  46 The main program
  47 .Bl -dash -compact
  48 .It
  49 limits execution time;
  50 .It
  51 changes to
  52 .Dv MAN_DIR ,
  53 the data directory containing all the manual trees;
  54 .It
  55 calls
  56 .Fn parse_manpath_conf ;
  57 .It
  58 if
  59 .Ev PATH_INFO
  60 is empty, calls
  61 .Fn parse_query_string ;
  62 otherwise,
  63 calls
  64 .Fn parse_path_info ;
  65 .It
  66 validates the manpath and the architecture;
  67 .It
  68 calls the appropriate one among the
  69 .Sx Page generators .
  70 .El
  71 .It Ft void Fn parse_manpath_conf "struct req *req"
  72 Parses and validates
  73 .Pa manpath.conf
  74 and fills
  75 .Va req->p
  76 and
  77 .Va req->psz .
  78 .It Ft void Fn parse_path_info "struct req *req" "const char *path"
  79 Parses and validates
  80 .Ev PATH_INFO ,
  81 clears
  82 .Va req->isquery ,
  83 and fills
  84 .Va req->q .
  85 .It Ft void Fn parse_query_string "struct req *req" "const char *qs"
  86 Parses and validates
  87 .Ev QUERY_STRING ,
  88 sets
  89 .Va req->isquery ,
  90 and fills
  91 .Va req->q .
  92 This function is the only user of the utility functions
  93 .Fn http_decode
  94 and
  95 .Fn set_query_attr .
  96 .El
  97 .Ss Page generators
  98 The purpose of each page generator is to print a complete HTML page,
  99 starting with the HTTP headers and continuing to the page footer.
 100 Before starting HTML output with
 101 .Fn resp_begin_html ,
 102 some page generators do some preparatory work, for example to decide
 103 which page to show.
 104 Each page generator ends with a call to
 105 .Fn resp_end_html .
 106 .Bl -tag -width 1n
 107 .It Ft void Fn pg_show "struct req *req" "const char *fullpath"
 108 This page generator is used when
 109 .Ev PATH_INFO
 110 contains the complete path to a manual page including manpath,
 111 section directory, optional architecture subdirectory, manual name
 112 and section number suffix.
 113 It validates the manpath, changes into it, validate the filename,
 114 and then calls
 115 .Fn resp_begin_html ,
 116 .Fn resp_searchform ,
 117 .Fn resp_show ,
 118 and
 119 .Fn resp_end_html
 120 in that order.
 121 .It Ft void Fn pg_search "const struct req *req"
 122 This page generator is used when
 123 .Ev PATH_INFO
 124 contains a search query in short format or when
 125 .Ev PATH_INFO
 126 is empty and a
 127 .Ev QUERY_STRING
 128 is provided.
 129 If possible, requests using
 130 .Ev QUERY_STRING
 131 are redirected to URIs using
 132 .Ev PATH_INFO
 133 by calling
 134 .Fn pg_redirect .
 135 Otherwise, it changes into the manpath and calls
 136 .Xr mansearch 3 .
 137 Depending on the result, it calls either
 138 .Fn pg_noresult
 139 or
 140 .Fn pg_searchres .
 141 .It Ft void Fn pg_redirect "const struct req *req" "const char *name"
 142 This function is special in so far as it does not print an HTML page,
 143 but only an HTTP 303 response with a Location: of the form:
 144 .Sm off
 145 .No http://
 146 .Ar host Ns /
 147 .Op Ar scriptname Ns /
 148 .Op Ar manpath Ns /
 149 .Op Ar arch Ns /
 150 .Fa name
 151 .Op Pf . Ar sec
 152 .Sm on
 153 .It Ft void Fn pg_noresult "const struct req *req" "const char *msg"
 154 This function calls
 155 .Fn resp_begin_html ,
 156 .Fn resp_searchform ,
 157 prints the
 158 .Fa msg
 159 passed to it, and calls
 160 .Fn resp_end_html .
 161 .It Ft void Fn pg_searchres "const struct req *req" "struct manpage *r"\
 162  "size_t sz"
 163 This function first validates the filenames found.
 164 If
 165 .Ev QUERY_STRING
 166 was used and there is exactly one result,
 167 it writes an HTTP redirect to that result.
 168 Otherwise, it writes an HTML result page beginning with
 169 .Fn resp_begin_html
 170 and
 171 .Fn resp_searchform .
 172 If there is more than one result, it writes a list of links
 173 to all the results.
 174 If it was a
 175 .Xr man 1
 176 rather than an
 177 .Xr apropos 1
 178 query or if there is only one single result, it calls
 179 .Fn resp_show .
 180 Finally, it calls
 181 .Fn resp_end_html .
 182 .It Ft void Fn pg_index "const struct req *req"
 183 This page generator is used when
 184 .Ev PATH_INFO
 185 and
 186 .Ev QUERY_STRING
 187 are both empty.
 188 It calls
 189 .Fn resp_begin_html
 190 and
 191 .Fn resp_searchform ,
 192 writes links to help pages, and calls
 193 .Fn resp_end_html .
 194 .It Ft void Fn pg_error_badrequest "const char *msg"
 195 This page generator is used when
 196 .Fn main
 197 or
 198 .Fn pg_show
 199 detect an invalid URI.
 200 It calls
 201 .Fn resp_begin_html ,
 202 prints the
 203 .Fa msg
 204 provided, and calls
 205 .Fn resp_end_html .
 206 .It Ft void Fn pg_error_internal void
 207 This page generator is used by various functions when errors are
 208 detected in the
 209 .Pa manpath.conf
 210 configuration file, in
 211 .Xr mandoc.db 5
 212 databases, in the
 213 .Xr mandoc 3
 214 parser, in file system permissions, or when setting up timeouts.
 215 It calls
 216 .Fn resp_begin_html ,
 217 prints
 218 .Qq "Internal Server Error" ,
 219 and calls
 220 .Fn resp_end_html .
 221 Before calling
 222 .Fn pg_error_internal ,
 223 call
 224 .Xr warn 3
 225 or
 226 .Xr warnx 3
 227 to log the reason of the error to the
 228 .Xr httpd 8
 229 server log file.
 230 .El
 231 .Ss Result generators
 232 The purpose of result generators is to print a chunk of HTML code.
 233 When they print untrusted strings or characters,
 234 .Fn html_print
 235 and
 236 .Fn html_putchar
 237 are used.
 238 The highest level result generators are:
 239 .Bl -tag -width 1n
 240 .It Ft void Fn resp_begin_html "int code" "const char *msg"
 241 This generator calls
 242 .Fn resp_begin_http
 243 to print the HTTP headers, then prints the HTML header up to the
 244 opening tag of the <body> element, then copies the file
 245 .Pa header.html
 246 to the output, if it exists and is readable.
 247 .It Ft void Fn resp_searchform "const struct req *req" "enum focus focus"
 248 This generator prints a search form, filling it with data
 249 from the provided request object.
 250 If the
 251 .Fa focus
 252 argument is
 253 .Dv FOCUS_QUERY ,
 254 it sets the document's autofocus to the query input box.
 255 .It Ft void Fn resp_show "const struct req *req" "const char *file"
 256 This wrapper dispatches to either
 257 .Fn resp_catman
 258 or
 259 .Fn resp_format ,
 260 depending on whether
 261 .Ar file
 262 starts with
 263 .Pa cat
 264 or
 265 .Pa man ,
 266 respectively.
 267 .It Ft void Fn resp_catman "const struct req *req" "const char *file"
 268 This generator translates a preformatted, backspace-encoded manual
 269 page to HTML and prints it to the output.
 270 .It Ft void Fn resp_format "const struct req *req" "const char *file"
 271 This generator formats a manual page on the standard output,
 272 using the functions documented in
 273 .Xr mchars_alloc 3
 274 and
 275 .Xr mandoc 3 .
 276 .It Ft void Fn resp_end_html void
 277 This generator copies the file
 278 .Pa footer.html
 279 to the output, if it exists and is readable,
 280 and closes the <body> and <html> elements.
 281 .El
 282 .Ss Utility routines
 283 These functions take a string and return 1 if it is valid, or 0 otherwise.
 284 .Bl -tag -width 1n
 285 .It Ft int Fn validate_urifrag "const char *frag"
 286 Checks that the string only contains alphanumeric ASCII characters,
 287 dashes, dots, slashes, and underscores.
 288 .It Ft int Fn validate_manpath "const struct req *req" "const char* manpath"
 289 Checks that the string is either
 290 .Qq mandoc
 291 or one of the manpaths configured in
 292 .Pa manpath.conf .
 293 .It Ft int Fn validate_filename "const char *file"
 294 Checks that the string starts with
 295 .Qq man
 296 or
 297 .Qq cat
 298 and does not ascend to parent directories.
 299 .El
 300 .Sh SEE ALSO
 301 .Xr mandoc 3 ,
 302 .Xr mansearch 3 ,
 303 .Xr mchars_alloc 3 ,
 304 .Xr mandoc.db 5 ,
 305 .Xr man.cgi 8