src/errorpage.h

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 04    Error Generation */
  10
  11 #ifndef   SQUID_ERRORPAGE_H
  12 #define   SQUID_ERRORPAGE_H
  13
  14 #include "cbdata.h"
  15 #include "comm/forward.h"
  16 #include "error/Detail.h"
  17 #include "error/forward.h"
  18 #include "http/forward.h"
  19 #include "http/StatusCode.h"
  20 #include "ip/Address.h"
  21 #include "log/forward.h"
  22 #include "sbuf/SBuf.h"
  23 #include "SquidString.h"
  24 /* auth/UserRequest.h is empty unless USE_AUTH is defined */
  25 #include "auth/UserRequest.h"
  26
  27 /// error page callback
  28 typedef void ERCB(int fd, void *, size_t);
  29
  30 /**
  31  \defgroup ErrorPageAPI Error Pages API
  32  \ingroup Components
  33  \section ErrorPageStringCodes Error Page % codes for text insertion.
  34  *
  35  \verbatim
  36    a - User identity                            x
  37    A - Local listening IP address               x
  38    B - URL with FTP %2f hack                    x
  39    c - Squid error code                         x
  40    d - seconds elapsed since request received   x
  41    D - Error details                            x
  42    e - errno                                    x
  43    E - strerror()                               x
  44    f - FTP request line                         x
  45    F - FTP reply line                           x
  46    g - FTP server message                       x
  47    h - cache hostname                           x
  48    H - server host name                         x
  49    i - client IP address                        x
  50    I - server IP address                        x
  51    l - HREF link for CSS stylesheet inclusion   x
  52    L - HREF link for more info/contact          x
  53    M - Request Method                           x
  54    m - Error message returned by auth helper    x
  55    o - Message returned external acl helper     x
  56    p - URL port #                               x
  57    P - Protocol                                 x
  58    R - Full HTTP Request                        x
  59    S - squid signature from ERR_SIGNATURE       x
  60    s - caching proxy software with version      x
  61    t - local time                               x
  62    T - UTC                                      x
  63    U - URL without password                     x
  64    u - URL with password                        x
  65    w - cachemgr email address                   x
  66    W - error data (to be included in the mailto links)
  67    x - error name                               x
  68    z - dns server error message                 x
  69    Z - Preformatted error message               x
  70  \endverbatim
  71  *
  72  * Plus logformat %codes embedded using @Squid{%logformat_code} syntax.
  73  */
  74
  75 class MemBuf;
  76 class StoreEntry;
  77 class wordlist;
  78
  79 namespace ErrorPage {
  80
  81 class Build;
  82
  83 } // namespace ErrorPage
  84
  85 /// \ingroup ErrorPageAPI
  86 class ErrorState
  87 {
  88     CBDATA_CLASS(ErrorState);
  89
  90 public:
  91     /// creates an error of type other than ERR_RELAY_REMOTE
  92     ErrorState(err_type type, Http::StatusCode, HttpRequest * request, const AccessLogEntryPointer &al);
  93     ErrorState() = delete; // not implemented.
  94
  95     /// creates an ERR_RELAY_REMOTE error
  96     ErrorState(HttpRequest * request, HttpReply *);
  97
  98     ~ErrorState();
  99
 100     /// Creates a general request forwarding error with the right http_status.
 101     static ErrorState *NewForwarding(err_type, HttpRequestPointer &, const AccessLogEntryPointer &);
 102
 103     /**
 104      * Allocates and initializes an error response
 105      */
 106     HttpReply *BuildHttpReply(void);
 107
 108     /// set error type-specific detail code
 109     void detailError(const ErrorDetail::Pointer &dCode) { detail = dCode; }
 110
 111     /// ensures that a future BuildHttpReply() is likely to succeed
 112     void validate();
 113
 114     /// the source of the error template (for reporting purposes)
 115     SBuf inputLocation;
 116
 117 private:
 118     typedef ErrorPage::Build Build;
 119
 120     /// initializations shared by public constructors
 121     explicit ErrorState(err_type type);
 122
 123     /// locates the right error page template for this error and compiles it
 124     SBuf buildBody();
 125
 126     /// compiles error page or error detail template (i.e. anything but deny_url)
 127     /// \param input  the template text to be compiled
 128     /// \param allowRecursion  whether to compile %codes which produce %codes
 129     SBuf compileBody(const char *text, bool allowRecursion);
 130
 131     /// compile a single-letter %code like %D
 132     void compileLegacyCode(Build &build);
 133
 134     /// compile @Squid{%code} sequence containing a single logformat %code
 135     void compileLogformatCode(Build &build);
 136
 137     /// replaces all legacy and logformat %codes in the given input
 138     /// \param input  the template text to be converted
 139     /// \param building_deny_info_url  whether input is a deny_info URL parameter
 140     /// \param allowRecursion  whether to compile %codes which produce %codes
 141     /// \returns the given input with all %codes substituted
 142     SBuf compile(const char *input, bool building_deny_info_url, bool allowRecursion);
 143
 144     /// React to a compile() error, throwing if buildContext allows.
 145     /// \param msg description of what went wrong
 146     /// \param near approximate start of the problematic input
 147     void noteBuildError(const char *msg, const char *near) {
 148         noteBuildError_(msg, near, false);
 149     }
 150
 151     /// Note a compile() error but do not throw for backwards
 152     /// compatibility with older configurations that may have such errors.
 153     /// Should eventually be replaced with noteBuildError().
 154     /// \param msg description of what went wrong
 155     /// \param near approximate start of the problematic input
 156     void bypassBuildErrorXXX(const char *msg, const char *near) {
 157         noteBuildError_(msg, near, true);
 158     }
 159
 160     /**
 161      * CacheManager / Debug dump of the ErrorState object.
 162      * Writes output into the given MemBuf.
 163      \retval 0 successful completion.
 164      */
 165     int Dump(MemBuf * mb);
 166
 167 public:
 168     err_type type = ERR_NONE;
 169     int page_id = ERR_NONE;
 170     char *err_language = nullptr;
 171     Http::StatusCode httpStatus = Http::scNone;
 172 #if USE_AUTH
 173     Auth::UserRequest::Pointer auth_user_request;
 174 #endif
 175     HttpRequestPointer request;
 176     char *url = nullptr;
 177     int xerrno = 0;
 178     unsigned short port = 0;
 179     String dnsError; ///< DNS lookup error message
 180     time_t ttl = 0;
 181
 182     Ip::Address src_addr;
 183     char *redirect_url = nullptr;
 184     ERCB *callback;
 185     void *callback_data = nullptr;
 186
 187     struct {
 188         wordlist *server_msg = nullptr;
 189         char *request = nullptr;
 190         char *reply = nullptr;
 191         char *cwd_msg = nullptr;
 192         MemBuf *listing = nullptr;
 193     } ftp;
 194
 195     char *request_hdrs = nullptr;
 196     char *err_msg = nullptr; /* Preformatted error message from the cache */
 197
 198     AccessLogEntryPointer ale; ///< transaction details (or nil)
 199
 200     // TODO: Replace type, xerrno and detail with Error while adding a virtual
 201     // Error::Detail::sysError() method to extract errno in detailError().
 202     /// type-specific detail about the transaction error;
 203     /// overwrites xerrno;
 204     ErrorDetail::Pointer detail;
 205
 206     HttpReplyPointer response_;
 207
 208 private:
 209     void noteBuildError_(const char *msg, const char *near, const bool forceBypass);
 210
 211     static const SBuf LogformatMagic; ///< marks each embedded logformat entry
 212 };
 213
 214 /**
 215  \ingroup ErrorPageAPI
 216  *
 217  * This function finds the error messages formats, and stores
 218  * them in error_text[]
 219  *
 220  \par Global effects:
 221  *            error_text[] - is modified
 222  */
 223 void errorInitialize(void);
 224
 225 /// \ingroup ErrorPageAPI
 226 void errorClean(void);
 227
 228 /**
 229  * \ingroup ErrorPageAPI
 230  *
 231  * This function generates a error page from the info contained
 232  * by err and then sends it to the client.
 233  * The callback function errorSendComplete() is called after
 234  * the page has been written to the client (clientConn).
 235  * errorSendComplete() deallocates err.  We need to add
 236  * err to the cbdata because comm_write() requires it
 237  * for all callback data pointers.
 238  *
 239  \note normally errorSend() should only be called from
 240  *     routines in ssl.c and pass.c, where we don't have any
 241  *     StoreEntry's.  In client_side.c we must allocate a StoreEntry
 242  *     for errors and use errorAppendEntry() to account for
 243  *     persistent/pipeline connections.
 244  *
 245  \param clientConn  socket where page object is to be written
 246  \param err         This object is destroyed after use in this function.
 247  */
 248 void errorSend(const Comm::ConnectionPointer &conn, ErrorState *err);
 249
 250 /**
 251  \ingroup ErrorPageAPI
 252  *
 253  * This function generates a error page from the info contained
 254  * by err and then stores the text in the specified store
 255  * entry.
 256  * This function should only be called by "server
 257  * side routines" which need to communicate errors to the
 258  * client side.  It should also be called from client_side.c
 259  * because we now support persistent connections, and
 260  * cannot assume that we can immediately write to the socket
 261  * for an error.
 262  *
 263  \param entry   ??
 264  \param err     This object is destroyed after use in this function.
 265  */
 266 void errorAppendEntry(StoreEntry *entry, ErrorState *err);
 267
 268 /// allocates a new slot for the error page
 269 err_type errorReservePageId(const char *page_name, const SBuf &cfgLocation);
 270
 271 const char *errorPageName(int pageId); ///< error ID to string
 272
 273 /**
 274  \ingroup ErrorPageAPI
 275  *
 276  * loads text templates used for error pages and details;
 277  * supports translation of templates
 278  */
 279 class TemplateFile
 280 {
 281 public:
 282     TemplateFile(const char *name, const err_type code);
 283     virtual ~TemplateFile() {}
 284
 285     /// return true if the data loaded from disk without any problem
 286     bool loaded() const {return wasLoaded;}
 287
 288     /**
 289      * Load the page_name template from a file which  probably exist at:
 290      *  (a) admin specified custom directory (error_directory)
 291      *  (b) default language translation directory (error_default_language)
 292      *  (c) English sub-directory where errors should ALWAYS exist
 293      * If all of the above fail, setDefault() is called.
 294      */
 295     void loadDefault();
 296
 297     /**
 298      * Load an error template for a given HTTP request. This function examines the
 299      * Accept-Language header and select the first available template. If the default
 300      * template selected (eg because of a "Accept-Language: *"), or not available
 301      * template found this function return false.
 302      */
 303     bool loadFor(const HttpRequest *request);
 304
 305     /**
 306      * Load the file given by "path". It uses the "parse()" method.
 307      * On success return true and sets the "defined" member
 308      */
 309     bool loadFromFile(const char *path);
 310
 311     /// The language used for the template
 312     const char *language() {return errLanguage.termedBuf();}
 313
 314     SBuf filename; ///< where the template was loaded from
 315
 316     bool silent; ///< Whether to print error messages on cache.log file or not. It is user defined.
 317
 318 protected:
 319     /// post-process the loaded template
 320     virtual bool parse() { return true; }
 321
 322     /// recover from loadDefault() failure to load or parse() a template
 323     virtual void setDefault() {}
 324
 325     /**
 326      * Try to load the "page_name" template for a given language "lang"
 327      * from squid errors directory
 328      \return true on success false otherwise
 329      */
 330     bool tryLoadTemplate(const char *lang);
 331
 332     SBuf template_; ///< raw template contents
 333     bool wasLoaded; ///< True if the template data read from disk without any problem
 334     String errLanguage; ///< The error language of the template.
 335     String templateName; ///< The name of the template
 336     err_type templateCode; ///< The internal code for this template.
 337 };
 338
 339 /**
 340  * Parses the Accept-Language header value and return one language item on
 341  * each call.
 342  * Will ignore any whitespace, q-values, and detectably invalid language
 343  * codes in the header.
 344  *
 345  * \param hdr is the Accept-Language header value
 346  * \param lang a buffer to store parsed language code in
 347  * \param langlen the length of the lang buffer
 348  * \param pos is used to store the offset state of parsing. Must be "0" on first call.
 349  *            Will be altered to point at the start of next field-value.
 350  * \return true if something looking like a language token has been placed in lang, false otherwise
 351  */
 352 bool strHdrAcptLangGetItem(const String &hdr, char *lang, int langLen, size_t &pos);
 353
 354 #endif /* SQUID_ERRORPAGE_H */
 355