/* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* * mod_negotiation.c: keeps track of MIME types the client is willing to * accept, and contains code to handle type arbitration. * * rst */ #include "apr.h" #include "apr_strings.h" #include "apr_file_io.h" #include "apr_lib.h" #define APR_WANT_STRFUNC #include "apr_want.h" #include "ap_config.h" #include "httpd.h" #include "http_config.h" #include "http_request.h" #include "http_protocol.h" #include "http_core.h" #include "http_log.h" #include "util_script.h" #define MAP_FILE_MAGIC_TYPE "application/x-type-map" /* Commands --- configuring document caching on a per (virtual?) * server basis... */ typedef struct { int forcelangpriority; apr_array_header_t *language_priority; } neg_dir_config; /* forcelangpriority flags */ #define FLP_UNDEF 0 /* Same as FLP_DEFAULT, but base overrides */ #define FLP_NONE 1 /* Return 406, HTTP_NOT_ACCEPTABLE */ #define FLP_PREFER 2 /* Use language_priority rather than MC */ #define FLP_FALLBACK 4 /* Use language_priority rather than NA */ #define FLP_DEFAULT FLP_PREFER /* env evaluation */ #define DISCARD_ALL_ENCODINGS 1 /* no-gzip */ #define DISCARD_ALL_BUT_HTML 2 /* gzip-only-text/html */ module AP_MODULE_DECLARE_DATA negotiation_module; static void *create_neg_dir_config(apr_pool_t *p, char *dummy) { neg_dir_config *new = (neg_dir_config *) apr_palloc(p, sizeof(neg_dir_config)); new->forcelangpriority = FLP_UNDEF; new->language_priority = NULL; return new; } static void *merge_neg_dir_configs(apr_pool_t *p, void *basev, void *addv) { neg_dir_config *base = (neg_dir_config *) basev; neg_dir_config *add = (neg_dir_config *) addv; neg_dir_config *new = (neg_dir_config *) apr_palloc(p, sizeof(neg_dir_config)); /* give priority to the config in the subdirectory */ new->forcelangpriority = (add->forcelangpriority != FLP_UNDEF) ? add->forcelangpriority : base->forcelangpriority; new->language_priority = add->language_priority ? add->language_priority : base->language_priority; return new; } static const char *set_language_priority(cmd_parms *cmd, void *n_, const char *lang) { neg_dir_config *n = n_; const char **langp; if (!n->language_priority) n->language_priority = apr_array_make(cmd->pool, 4, sizeof(char *)); langp = (const char **) apr_array_push(n->language_priority); *langp = lang; return NULL; } static const char *set_force_priority(cmd_parms *cmd, void *n_, const char *w) { neg_dir_config *n = n_; if (!strcasecmp(w, "None")) { if (n->forcelangpriority & ~FLP_NONE) { return "Cannot combine ForceLanguagePriority options with None"; } n->forcelangpriority = FLP_NONE; } else if (!strcasecmp(w, "Prefer")) { if (n->forcelangpriority & FLP_NONE) { return "Cannot combine ForceLanguagePriority options None and " "Prefer"; } n->forcelangpriority |= FLP_PREFER; } else if (!strcasecmp(w, "Fallback")) { if (n->forcelangpriority & FLP_NONE) { return "Cannot combine ForceLanguagePriority options None and " "Fallback"; } n->forcelangpriority |= FLP_FALLBACK; } else { return apr_pstrcat(cmd->pool, "Invalid ForceLanguagePriority option ", w, NULL); } return NULL; } static const char *cache_negotiated_docs(cmd_parms *cmd, void *dummy, int arg) { ap_set_module_config(cmd->server->module_config, &negotiation_module, (arg ? "Cache" : NULL)); return NULL; } static int do_cache_negotiated_docs(server_rec *s) { return (ap_get_module_config(s->module_config, &negotiation_module) != NULL); } static const command_rec negotiation_cmds[] = { AP_INIT_FLAG("CacheNegotiatedDocs", cache_negotiated_docs, NULL, RSRC_CONF, "Either 'on' or 'off' (default)"), AP_INIT_ITERATE("LanguagePriority", set_language_priority, NULL, OR_FILEINFO, "space-delimited list of MIME language abbreviations"), AP_INIT_ITERATE("ForceLanguagePriority", set_force_priority, NULL, OR_FILEINFO, "Force LanguagePriority elections, either None, or " "Fallback and/or Prefer"), {NULL} }; /* * Record of available info on a media type specified by the client * (we also use 'em for encodings and languages) */ typedef struct accept_rec { char *name; /* MUST be lowercase */ float quality; float level; char *charset; /* for content-type only */ } accept_rec; /* * Record of available info on a particular variant * * Note that a few of these fields are updated by the actual negotiation * code. These are: * * level_matched --- initialized to zero. Set to the value of level * if the client actually accepts this media type at that * level (and *not* if it got in on a wildcard). See level_cmp * below. * mime_stars -- initialized to zero. Set to the number of stars * present in the best matching Accept header element. * 1 for star/star, 2 for type/star and 3 for * type/subtype. * * definite -- initialized to 1. Set to 0 if there is a match which * makes the variant non-definite according to the rules * in rfc2296. */ typedef struct var_rec { request_rec *sub_req; /* May be NULL (is, for map files) */ const char *mime_type; /* MUST be lowercase */ const char *file_name; /* Set to 'this' (for map file body content) */ apr_off_t body; /* Only for map file body content */ const char *content_encoding; apr_array_header_t *content_languages; /* list of lang. for this variant */ const char *content_charset; const char *description; /* The next five items give the quality values for the dimensions * of negotiation for this variant. They are obtained from the * appropriate header lines, except for source_quality, which * is obtained from the variant itself (the 'qs' parameter value * from the variant's mime-type). Apart from source_quality, * these values are set when we find the quality for each variant * (see best_match()). source_quality is set from the 'qs' parameter * of the variant description or mime type: see set_mime_fields(). */ float lang_quality; /* quality of this variant's language */ float encoding_quality; /* ditto encoding */ float charset_quality; /* ditto charset */ float mime_type_quality; /* ditto media type */ float source_quality; /* source quality for this variant */ /* Now some special values */ float level; /* Auxiliary to content-type... */ apr_off_t bytes; /* content length, if known */ int lang_index; /* Index into LanguagePriority list */ int is_pseudo_html; /* text/html, *or* the INCLUDES_MAGIC_TYPEs */ /* Above are all written-once properties of the variant. The * three fields below are changed during negotiation: */ float level_matched; int mime_stars; int definite; } var_rec; /* Something to carry around the state of negotiation (and to keep * all of this thread-safe)... */ typedef struct { apr_pool_t *pool; request_rec *r; neg_dir_config *conf; char *dir_name; int accept_q; /* 1 if an Accept item has a q= param */ float default_lang_quality; /* fiddle lang q for variants with no lang */ /* the array pointers below are NULL if the corresponding accept * headers are not present */ apr_array_header_t *accepts; /* accept_recs */ apr_array_header_t *accept_encodings; /* accept_recs */ apr_array_header_t *accept_charsets; /* accept_recs */ apr_array_header_t *accept_langs; /* accept_recs */ apr_array_header_t *avail_vars; /* available variants */ int count_multiviews_variants; /* number of variants found on disk */ int is_transparent; /* 1 if this resource is trans. negotiable */ int dont_fiddle_headers; /* 1 if we may not fiddle with accept hdrs */ int ua_supports_trans; /* 1 if ua supports trans negotiation */ int send_alternates; /* 1 if we want to send an Alternates header */ int may_choose; /* 1 if we may choose a variant for the client */ int use_rvsa; /* 1 if we must use RVSA/1.0 negotiation algo */ } negotiation_state; /* A few functions to manipulate var_recs. * Cleaning out the fields... */ static void clean_var_rec(var_rec *mime_info) { mime_info->sub_req = NULL; mime_info->mime_type = ""; mime_info->file_name = ""; mime_info->body = 0; mime_info->content_encoding = NULL; mime_info->content_languages = NULL; mime_info->content_charset = ""; mime_info->description = ""; mime_info->is_pseudo_html = 0; mime_info->level = 0.0f; mime_info->level_matched = 0.0f; mime_info->bytes = -1; mime_info->lang_index = -1; mime_info->mime_stars = 0; mime_info->definite = 1; mime_info->charset_quality = 1.0f; mime_info->encoding_quality = 1.0f; mime_info->lang_quality = 1.0f; mime_info->mime_type_quality = 1.0f; mime_info->source_quality = 0.0f; } /* Initializing the relevant fields of a variant record from the * accept_info read out of its content-type, one way or another. */ static void set_mime_fields(var_rec *var, accept_rec *mime_info) { var->mime_type = mime_info->name; var->source_quality = mime_info->quality; var->level = mime_info->level; var->content_charset = mime_info->charset; var->is_pseudo_html = (!strcmp(var->mime_type, "text/html") || !strcmp(var->mime_type, INCLUDES_MAGIC_TYPE) || !strcmp(var->mime_type, INCLUDES_MAGIC_TYPE3)); } /* Create a variant list validator in r using info from vlistr. */ static void set_vlist_validator(request_rec *r, request_rec *vlistr) { /* Calculating the variant list validator is similar to * calculating an etag for the source of the variant list * information, so we use ap_make_etag(). Note that this * validator can be 'weak' in extreme case. */ ap_update_mtime(vlistr, vlistr->finfo.mtime); r->vlist_validator = ap_make_etag(vlistr, 0); /* ap_set_etag will later take r->vlist_validator into account * when creating the etag header */ } /***************************************************************** * * Parsing (lists of) media types and their parameters, as seen in * HTTPD header lines and elsewhere. */ /* * parse quality value. atof(3) is not well-usable here, because it * depends on the locale (argh). * * However, RFC 2616 states: * 3.9 Quality Values * * [...] HTTP/1.1 applications MUST NOT generate more than three digits * after the decimal point. User configuration of these values SHOULD also * be limited in this fashion. * * qvalue = ( "0" [ "." 0*3DIGIT ] ) * | ( "1" [ "." 0*3("0") ] ) * * This is quite easy. If the supplied string doesn't match the above * definition (loosely), we simply return 1 (same as if there's no qvalue) */ static float atoq(const char *string) { if (!string || !*string) { return 1.0f; } while (*string && apr_isspace(*string)) { ++string; } /* be tolerant and accept qvalues without leading zero * (also for backwards compat, where atof() was in use) */ if (*string != '.' && *string++ != '0') { return 1.0f; } if (*string == '.') { /* better only one division later, than dealing with fscking * IEEE format 0.1 factors ... */ int i = 0; if (*++string >= '0' && *string <= '9') { i += (*string - '0') * 100; if (*++string >= '0' && *string <= '9') { i += (*string - '0') * 10; if (*++string > '0' && *string <= '9') { i += (*string - '0'); } } } return (float)i / 1000.0f; } return 0.0f; } /* * Get a single mime type entry --- one media type and parameters; * enter the values we recognize into the argument accept_rec */ static const char *get_entry(apr_pool_t *p, accept_rec *result, const char *accept_line) { result->quality = 1.0f; result->level = 0.0f; result->charset = ""; /* * Note that this handles what I gather is the "old format", * * Accept: text/html text/plain moo/zot * * without any compatibility kludges --- if the token after the * MIME type begins with a semicolon, we know we're looking at parms, * otherwise, we know we aren't. (So why all the pissing and moaning * in the CERN server code? I must be missing something). */ result->name = ap_get_token(p, &accept_line, 0); ap_str_tolower(result->name); /* You want case insensitive, * you'll *get* case insensitive. */ /* KLUDGE!!! Default HTML to level 2.0 unless the browser * *explicitly* says something else. */ if (!strcmp(result->name, "text/html") && (result->level == 0.0)) { result->level = 2.0f; } else if (!strcmp(result->name, INCLUDES_MAGIC_TYPE)) { result->level = 2.0f; } else if (!strcmp(result->name, INCLUDES_MAGIC_TYPE3)) { result->level = 3.0f; } while (*accept_line == ';') { /* Parameters ... */ char *parm; char *cp; char *end; ++accept_line; parm = ap_get_token(p, &accept_line, 1); /* Look for 'var = value' --- and make sure the var is in lcase. */ for (cp = parm; (*cp && !apr_isspace(*cp) && *cp != '='); ++cp) { *cp = apr_tolower(*cp); } if (!*cp) { continue; /* No '='; just ignore it. */ } *cp++ = '\0'; /* Delimit var */ while (*cp && (apr_isspace(*cp) || *cp == '=')) { ++cp; } if (*cp == '"') { ++cp; for (end = cp; (*end && *end != '\n' && *end != '\r' && *end != '\"'); end++); } else { for (end = cp; (*end && !apr_isspace(*end)); end++); } if (*end) { *end = '\0'; /* strip ending quote or return */ } ap_str_tolower(cp); if (parm[0] == 'q' && (parm[1] == '\0' || (parm[1] == 's' && parm[2] == '\0'))) { result->quality = atoq(cp); } else if (parm[0] == 'l' && !strcmp(&parm[1], "evel")) { result->level = (float)atoi(cp); } else if (!strcmp(parm, "charset")) { result->charset = cp; } } if (*accept_line == ',') { ++accept_line; } return accept_line; } /***************************************************************** * * Dealing with header lines ... * * Accept, Accept-Charset, Accept-Language and Accept-Encoding * are handled by do_header_line() - they all have the same * basic structure of a list of items of the format * name; q=N; charset=TEXT * * where charset is only valid in Accept. */ static apr_array_header_t *do_header_line(apr_pool_t *p, const char *accept_line) { apr_array_header_t *accept_recs; if (!accept_line) { return NULL; } accept_recs = apr_array_make(p, 40, sizeof(accept_rec)); while (*accept_line) { accept_rec *new = (accept_rec *) apr_array_push(accept_recs); accept_line = get_entry(p, new, accept_line); } return accept_recs; } /* Given the text of the Content-Languages: line from the var map file, * return an array containing the languages of this variant */ static apr_array_header_t *do_languages_line(apr_pool_t *p, const char **lang_line) { apr_array_header_t *lang_recs = apr_array_make(p, 2, sizeof(char *)); if (!lang_line) { return lang_recs; } while (**lang_line) { char **new = (char **) apr_array_push(lang_recs); *new = ap_get_token(p, lang_line, 0); ap_str_tolower(*new); if (**lang_line == ',' || **lang_line == ';') { ++(*lang_line); } } return lang_recs; } /***************************************************************** * * Handling header lines from clients... */ static negotiation_state *parse_accept_headers(request_rec *r) { negotiation_state *new = (negotiation_state *) apr_pcalloc(r->pool, sizeof(negotiation_state)); accept_rec *elts; apr_table_t *hdrs = r->headers_in; int i; new->pool = r->pool; new->r = r; new->conf = (neg_dir_config *)ap_get_module_config(r->per_dir_config, &negotiation_module); new->dir_name = ap_make_dirstr_parent(r->pool, r->filename); new->accepts = do_header_line(r->pool, apr_table_get(hdrs, "Accept")); /* calculate new->accept_q value */ if (new->accepts) { elts = (accept_rec *) new->accepts->elts; for (i = 0; i < new->accepts->nelts; ++i) { if (elts[i].quality < 1.0) { new->accept_q = 1; } } } new->accept_encodings = do_header_line(r->pool, apr_table_get(hdrs, "Accept-Encoding")); new->accept_langs = do_header_line(r->pool, apr_table_get(hdrs, "Accept-Language")); new->accept_charsets = do_header_line(r->pool, apr_table_get(hdrs, "Accept-Charset")); /* This is possibly overkill for some servers, heck, we have * only 33 index.html variants in docs/docroot (today). * Make this configurable? */ new->avail_vars = apr_array_make(r->pool, 40, sizeof(var_rec)); return new; } static void parse_negotiate_header(request_rec *r, negotiation_state *neg) { const char *negotiate = apr_table_get(r->headers_in, "Negotiate"); char *tok; /* First, default to no TCN, no Alternates, and the original Apache * negotiation algorithm with fiddles for broken browser configs. * * To save network bandwidth, we do not configure to send an * Alternates header to the user agent by default. User * agents that want an Alternates header for agent-driven * negotiation will have to request it by sending an * appropriate Negotiate header. */ neg->ua_supports_trans = 0; neg->send_alternates = 0; neg->may_choose = 1; neg->use_rvsa = 0; neg->dont_fiddle_headers = 0; if (!negotiate) return; if (strcmp(negotiate, "trans") == 0) { /* Lynx 2.7 and 2.8 send 'negotiate: trans' even though they * do not support transparent content negotiation, so for Lynx we * ignore the negotiate header when its contents are exactly "trans". * If future versions of Lynx ever need to say 'negotiate: trans', * they can send the equivalent 'negotiate: trans, trans' instead * to avoid triggering the workaround below. */ const char *ua = apr_table_get(r->headers_in, "User-Agent"); if (ua && (strncmp(ua, "Lynx", 4) == 0)) return; } neg->may_choose = 0; /* An empty Negotiate would require 300 response */ while ((tok = ap_get_list_item(neg->pool, &negotiate)) != NULL) { if (strcmp(tok, "trans") == 0 || strcmp(tok, "vlist") == 0 || strcmp(tok, "guess-small") == 0 || apr_isdigit(tok[0]) || strcmp(tok, "*") == 0) { /* The user agent supports transparent negotiation */ neg->ua_supports_trans = 1; /* Send-alternates could be configurable, but note * that it must be 1 if we have 'vlist' in the * negotiate header. */ neg->send_alternates = 1; if (strcmp(tok, "1.0") == 0) { /* we may use the RVSA/1.0 algorithm, configure for it */ neg->may_choose = 1; neg->use_rvsa = 1; neg->dont_fiddle_headers = 1; } else if (tok[0] == '*') { /* we may use any variant selection algorithm, configure * to use the Apache algorithm */ neg->may_choose = 1; /* We disable header fiddles on the assumption that a * client sending Negotiate knows how to send correct * headers which don't need fiddling. */ neg->dont_fiddle_headers = 1; } } } #ifdef NEG_DEBUG ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "dont_fiddle_headers=%d use_rvsa=%d ua_supports_trans=%d " "send_alternates=%d, may_choose=%d", neg->dont_fiddle_headers, neg->use_rvsa, neg->ua_supports_trans, neg->send_alternates, neg->may_choose); #endif } /* Sometimes clients will give us no Accept info at all; this routine sets * up the standard default for that case, and also arranges for us to be * willing to run a CGI script if we find one. (In fact, we set up to * dramatically prefer CGI scripts in cases where that's appropriate, * e.g., POST or when URI includes query args or extra path info). */ static void maybe_add_default_accepts(negotiation_state *neg, int prefer_scripts) { accept_rec *new_accept; if (!neg->accepts) { neg->accepts = apr_array_make(neg->pool, 4, sizeof(accept_rec)); new_accept = (accept_rec *) apr_array_push(neg->accepts); new_accept->name = "*/*"; new_accept->quality = 1.0f; new_accept->level = 0.0f; } new_accept = (accept_rec *) apr_array_push(neg->accepts); new_accept->name = CGI_MAGIC_TYPE; if (neg->use_rvsa) { new_accept->quality = 0; } else { new_accept->quality = prefer_scripts ? 2.0f : 0.001f; } new_accept->level = 0.0f; } /***************************************************************** * * Parsing type-map files, in Roy's meta/http format augmented with * #-comments. */ /* Reading RFC822-style header lines, ignoring #-comments and * handling continuations. */ enum header_state { header_eof, header_seen, header_sep }; static enum header_state get_header_line(char *buffer, int len, apr_file_t *map) { char *buf_end = buffer + len; char *cp; char c; /* Get a noncommented line */ do { if (apr_file_gets(buffer, MAX_STRING_LEN, map) != APR_SUCCESS) { return header_eof; } } while (buffer[0] == '#'); /* If blank, just return it --- this ends information on this variant */ for (cp = buffer; (*cp && apr_isspace(*cp)); ++cp) { continue; } if (*cp == '\0') { return header_sep; } /* If non-blank, go looking for header lines, but note that we still * have to treat comments specially... */ cp += strlen(cp); /* We need to shortcut the rest of this block following the Body: * tag - we will not look for continutation after this line. */ if (!strncasecmp(buffer, "Body:", 5)) return header_seen; while (apr_file_getc(&c, map) != APR_EOF) { if (c == '#') { /* Comment line */ while (apr_file_getc(&c, map) != APR_EOF && c != '\n') { continue; } } else if (apr_isspace(c)) { /* Leading whitespace. POSSIBLE continuation line * Also, possibly blank --- if so, we ungetc() the final newline * so that we will pick up the blank line the next time 'round. */ while (c != '\n' && apr_isspace(c)) { if(apr_file_getc(&c, map) != APR_SUCCESS) break; } apr_file_ungetc(c, map); if (c == '\n') { return header_seen; /* Blank line */ } /* Continuation */ while ( cp < buf_end - 2 && (apr_file_getc(&c, map)) != APR_EOF && c != '\n') { *cp++ = c; } *cp++ = '\n'; *cp = '\0'; } else { /* Line beginning with something other than whitespace */ apr_file_ungetc(c, map); return header_seen; } } return header_seen; } static apr_off_t get_body(char *buffer, apr_size_t *len, const char *tag, apr_file_t *map) { char *endbody; int bodylen; int taglen; apr_off_t pos; taglen = strlen(tag); *len -= taglen; /* We are at the first character following a body:tag\n entry * Suck in the body, then backspace to the first char after the * closing tag entry. If we fail to read, find the tag or back * up then we have a hosed file, so give up already */ if (apr_file_read(map, buffer, len) != APR_SUCCESS) { return -1; } /* put a copy of the tag *after* the data read from the file * so that strstr() will find something with no reliance on * terminating '\0' */ memcpy(buffer + *len, tag, taglen); endbody = strstr(buffer, tag); if (endbody == buffer + *len) { return -1; } bodylen = endbody - buffer; endbody += taglen; /* Skip all the trailing cruft after the end tag to the next line */ while (*endbody) { if (*endbody == '\n') { ++endbody; break; } ++endbody; } pos = -(apr_off_t)(*len - (endbody - buffer)); if (apr_file_seek(map, APR_CUR, &pos) != APR_SUCCESS) { return -1; } /* Give the caller back the actual body's file offset and length */ *len = bodylen; return pos - (endbody - buffer); } /* Stripping out RFC822 comments */ static void strip_paren_comments(char *hdr) { /* Hmmm... is this correct? In Roy's latest draft, (comments) can nest! */ /* Nope, it isn't correct. Fails to handle backslash escape as well. */ while (*hdr) { if (*hdr == '"') { hdr = strchr(hdr, '"'); if (hdr == NULL) { return; } ++hdr; } else if (*hdr == '(') { while (*hdr && *hdr != ')') { *hdr++ = ' '; } if (*hdr) { *hdr++ = ' '; } } else { ++hdr; } } } /* Getting to a header body from the header */ static char *lcase_header_name_return_body(char *header, request_rec *r) { char *cp = header; for ( ; *cp && *cp != ':' ; ++cp) { *cp = apr_tolower(*cp); } if (!*cp) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Syntax error in type map, no ':' in %s for header %s", r->filename, header); return NULL; } do { ++cp; } while (*cp && apr_isspace(*cp)); if (!*cp) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Syntax error in type map --- no header body: %s for %s", r->filename, header); return NULL; } return cp; } static int read_type_map(apr_file_t **map, negotiation_state *neg, request_rec *rr) { request_rec *r = neg->r; apr_file_t *map_ = NULL; apr_status_t status; char buffer[MAX_STRING_LEN]; enum header_state hstate; struct var_rec mime_info; int has_content; if (!map) map = &map_; /* We are not using multiviews */ neg->count_multiviews_variants = 0; if ((status = apr_file_open(map, rr->filename, APR_READ | APR_BUFFERED, APR_OS_DEFAULT, neg->pool)) != APR_SUCCESS) { ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, "cannot access type map file: %s", rr->filename); if (APR_STATUS_IS_ENOTDIR(status) || APR_STATUS_IS_ENOENT(status)) { return HTTP_NOT_FOUND; } else { return HTTP_FORBIDDEN; } } clean_var_rec(&mime_info); has_content = 0; do { hstate = get_header_line(buffer, MAX_STRING_LEN, *map); if (hstate == header_seen) { char *body1 = lcase_header_name_return_body(buffer, neg->r); const char *body; if (body1 == NULL) { return HTTP_INTERNAL_SERVER_ERROR; } strip_paren_comments(body1); body = body1; if (!strncmp(buffer, "uri:", 4)) { mime_info.file_name = ap_get_token(neg->pool, &body, 0); } else if (!strncmp(buffer, "content-type:", 13)) { struct accept_rec accept_info; get_entry(neg->pool, &accept_info, body); set_mime_fields(&mime_info, &accept_info); has_content = 1; } else if (!strncmp(buffer, "content-length:", 15)) { char *errp; apr_off_t number; if (apr_strtoff(&number, body, &errp, 10) || *errp || number < 0) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Parse error in type map, Content-Length: " "'%s' in %s is invalid.", body, r->filename); break; } mime_info.bytes = number; has_content = 1; } else if (!strncmp(buffer, "content-language:", 17)) { mime_info.content_languages = do_languages_line(neg->pool, &body); has_content = 1; } else if (!strncmp(buffer, "content-encoding:", 17)) { mime_info.content_encoding = ap_get_token(neg->pool, &body, 0); has_content = 1; } else if (!strncmp(buffer, "description:", 12)) { char *desc = apr_pstrdup(neg->pool, body); char *cp; for (cp = desc; *cp; ++cp) { if (*cp=='\n') *cp=' '; } if (cp>desc) *(cp-1)=0; mime_info.description = desc; } else if (!strncmp(buffer, "body:", 5)) { char *tag = apr_pstrdup(neg->pool, body); char *eol = strchr(tag, '\0'); apr_size_t len = MAX_STRING_LEN; while (--eol >= tag && apr_isspace(*eol)) *eol = '\0'; if ((mime_info.body = get_body(buffer, &len, tag, *map)) < 0) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Syntax error in type map, no end tag '%s'" "found in %s for Body: content.", tag, r->filename); break; } mime_info.bytes = len; mime_info.file_name = apr_filepath_name_get(rr->filename); } } else { if (*mime_info.file_name && has_content) { void *new_var = apr_array_push(neg->avail_vars); memcpy(new_var, (void *) &mime_info, sizeof(var_rec)); } clean_var_rec(&mime_info); has_content = 0; } } while (hstate != header_eof); if (map_) apr_file_close(map_); set_vlist_validator(r, rr); return OK; } /* Sort function used by read_types_multi. */ static int variantsortf(var_rec *a, var_rec *b) { /* First key is the source quality, sort in descending order. */ /* XXX: note that we currently implement no method of setting the * source quality for multiviews variants, so we are always comparing * 1.0 to 1.0 for now */ if (a->source_quality < b->source_quality) return 1; if (a->source_quality > b->source_quality) return -1; /* Second key is the variant name */ return strcmp(a->file_name, b->file_name); } /***************************************************************** * * Same as read_type_map, except we use a filtered directory listing * as the map... */ static int read_types_multi(negotiation_state *neg) { request_rec *r = neg->r; char *filp; int prefix_len; apr_dir_t *dirp; apr_finfo_t dirent; apr_status_t status; struct var_rec mime_info; struct accept_rec accept_info; void *new_var; int anymatch = 0; clean_var_rec(&mime_info); if (r->proxyreq || !r->filename || !ap_os_is_path_absolute(neg->pool, r->filename)) { return DECLINED; } /* Only absolute paths here */ if (!(filp = strrchr(r->filename, '/'))) { return DECLINED; } ++filp; prefix_len = strlen(filp); if ((status = apr_dir_open(&dirp, neg->dir_name, neg->pool)) != APR_SUCCESS) { ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, "cannot read directory for multi: %s", neg->dir_name); return HTTP_FORBIDDEN; } while (apr_dir_read(&dirent, APR_FINFO_DIRENT, dirp) == APR_SUCCESS) { apr_array_header_t *exception_list; request_rec *sub_req; /* Do we have a match? */ #ifdef CASE_BLIND_FILESYSTEM if (strncasecmp(dirent.name, filp, prefix_len)) { #else if (strncmp(dirent.name, filp, prefix_len)) { #endif continue; } if (dirent.name[prefix_len] != '.') { continue; } /* Don't negotiate directories and other unusual files * Really shouldn't see anything but DIR/LNK/REG here, * and we aught to discover if the LNK was interesting. * * Of course, this only helps platforms that capture the * the filetype in apr_dir_read(), which most can once * they are optimized with some magic [it's known to the * dirent, not associated to the inode, on most FS's.] */ if ((dirent.valid & APR_FINFO_TYPE) && (dirent.filetype == APR_DIR)) continue; /* Ok, something's here. Maybe nothing useful. Remember that * we tried, if we completely fail, so we can reject the request! */ anymatch = 1; /* See if it's something which we have access to, and which * has a known type and encoding (as opposed to something * which we'll be slapping default_type on later). */ sub_req = ap_sub_req_lookup_dirent(&dirent, r, AP_SUBREQ_MERGE_ARGS, NULL); /* Double check, we still don't multi-resolve non-ordinary files */ if (sub_req->finfo.filetype != APR_REG) continue; /* If it has a handler, we'll pretend it's a CGI script, * since that's a good indication of the sort of thing it * might be doing. */ if (sub_req->handler && !sub_req->content_type) { ap_set_content_type(sub_req, CGI_MAGIC_TYPE); } /* * mod_mime will _always_ provide us the base name in the * ap-mime-exception-list, if it processed anything. If * this list is empty, give up immediately, there was * nothing interesting. For example, looking at the files * readme.txt and readme.foo, we will throw away .foo if * it's an insignificant file (e.g. did not identify a * language, charset, encoding, content type or handler,) */ exception_list = (apr_array_header_t *)apr_table_get(sub_req->notes, "ap-mime-exceptions-list"); if (!exception_list) { ap_destroy_sub_req(sub_req); continue; } /* Each unregonized bit better match our base name, in sequence. * A test of index.html.foo will match index.foo or index.html.foo, * but it will never transpose the segments and allow index.foo.html * because that would introduce too much CPU consumption. Better that * we don't attempt a many-to-many match here. */ { int nexcept = exception_list->nelts; char **cur_except = (char**)exception_list->elts; char *segstart = filp, *segend, saveend; while (*segstart && nexcept) { if (!(segend = strchr(segstart, '.'))) segend = strchr(segstart, '\0'); saveend = *segend; *segend = '\0'; #ifdef CASE_BLIND_FILESYSTEM if (strcasecmp(segstart, *cur_except) == 0) { #else if (strcmp(segstart, *cur_except) == 0) { #endif --nexcept; ++cur_except; } if (!saveend) break; *segend = saveend; segstart = segend + 1; } if (nexcept) { /* Something you don't know is, something you don't know... */ ap_destroy_sub_req(sub_req); continue; } } /* * ###: be warned, the _default_ content type is already * picked up here! If we failed the subrequest, or don't * know what we are serving, then continue. */ if (sub_req->status != HTTP_OK || (!sub_req->content_type)) { ap_destroy_sub_req(sub_req); continue; } /* If it's a map file, we use that instead of the map * we're building... */ if (((sub_req->content_type) && !strcmp(sub_req->content_type, MAP_FILE_MAGIC_TYPE)) || ((sub_req->handler) && !strcmp(sub_req->handler, "type-map"))) { apr_dir_close(dirp); neg->avail_vars->nelts = 0; if (sub_req->status != HTTP_OK) { return sub_req->status; } return read_type_map(NULL, neg, sub_req); } /* Have reasonable variant --- gather notes. */ mime_info.sub_req = sub_req; mime_info.file_name = apr_pstrdup(neg->pool, dirent.name); if (sub_req->content_encoding) { mime_info.content_encoding = sub_req->content_encoding; } if (sub_req->content_languages) { mime_info.content_languages = sub_req->content_languages; } get_entry(neg->pool, &accept_info, sub_req->content_type); set_mime_fields(&mime_info, &accept_info); new_var = apr_array_push(neg->avail_vars); memcpy(new_var, (void *) &mime_info, sizeof(var_rec)); neg->count_multiviews_variants++; clean_var_rec(&mime_info); } apr_dir_close(dirp); /* We found some file names that matched. None could be served. * Rather than fall out to autoindex or some other mapper, this * request must die. */ if (anymatch && !neg->avail_vars->nelts) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "Negotiation: discovered file(s) matching request: %s" " (None could be negotiated).", r->filename); return HTTP_NOT_FOUND; } set_vlist_validator(r, r); /* Sort the variants into a canonical order. The negotiation * result sometimes depends on the order of the variants. By * sorting the variants into a canonical order, rather than using * the order in which readdir() happens to return them, we ensure * that the negotiation result will be consistent over filesystem * backup/restores and over all mirror sites. */ qsort((void *) neg->avail_vars->elts, neg->avail_vars->nelts, sizeof(var_rec), (int (*)(const void *, const void *)) variantsortf); return OK; } /***************************************************************** * And now for the code you've been waiting for... actually * finding a match to the client's requirements. */ /* Matching MIME types ... the star/star and foo/star commenting conventions * are implemented here. (You know what I mean by star/star, but just * try mentioning those three characters in a C comment). Using strcmp() * is legit, because everything has already been smashed to lowercase. * * Note also that if we get an exact match on the media type, we update * level_matched for use in level_cmp below... * * We also give a value for mime_stars, which is used later. It should * be 1 for star/star, 2 for type/star and 3 for type/subtype. */ static int mime_match(accept_rec *accept_r, var_rec *avail) { const char *accept_type = accept_r->name; const char *avail_type = avail->mime_type; int len = strlen(accept_type); if (accept_type[0] == '*') { /* Anything matches star/star */ if (avail->mime_stars < 1) { avail->mime_stars = 1; } return 1; } else if ((accept_type[len - 1] == '*') && !strncmp(accept_type, avail_type, len - 2)) { if (avail->mime_stars < 2) { avail->mime_stars = 2; } return 1; } else if (!strcmp(accept_type, avail_type) || (!strcmp(accept_type, "text/html") && (!strcmp(avail_type, INCLUDES_MAGIC_TYPE) || !strcmp(avail_type, INCLUDES_MAGIC_TYPE3)))) { if (accept_r->level >= avail->level) { avail->level_matched = avail->level; avail->mime_stars = 3; return 1; } } return OK; } /* This code implements a piece of the tie-breaking algorithm between * variants of equal quality. This piece is the treatment of variants * of the same base media type, but different levels. What we want to * return is the variant at the highest level that the client explicitly * claimed to accept. * * If all the variants available are at a higher level than that, or if * the client didn't say anything specific about this media type at all * and these variants just got in on a wildcard, we prefer the lowest * level, on grounds that that's the one that the client is least likely * to choke on. * * (This is all motivated by treatment of levels in HTML --- we only * want to give level 3 to browsers that explicitly ask for it; browsers * that don't, including HTTP/0.9 browsers that only get the implicit * "Accept: * / *" [space added to avoid confusing cpp --- no, that * syntax doesn't really work] should get HTML2 if available). * * (Note that this code only comes into play when we are choosing among * variants of equal quality, where the draft standard gives us a fair * bit of leeway about what to do. It ain't specified by the standard; * rather, it is a choice made by this server about what to do in cases * where the standard does not specify a unique course of action). */ static int level_cmp(var_rec *var1, var_rec *var2) { /* Levels are only comparable between matching media types */ if (var1->is_pseudo_html && !var2->is_pseudo_html) { return 0; } if (!var1->is_pseudo_html && strcmp(var1->mime_type, var2->mime_type)) { return 0; } /* The result of the above if statements is that, if we get to * here, both variants have the same mime_type or both are * pseudo-html. */ /* Take highest level that matched, if either did match. */ if (var1->level_matched > var2->level_matched) { return 1; } if (var1->level_matched < var2->level_matched) { return -1; } /* Neither matched. Take lowest level, if there's a difference. */ if (var1->level < var2->level) { return 1; } if (var1->level > var2->level) { return -1; } /* Tied */ return 0; } /* Finding languages. The main entry point is set_language_quality() * which is called for each variant. It sets two elements in the * variant record: * language_quality - the 'q' value of the 'best' matching language * from Accept-Language: header (HTTP/1.1) * lang_index - Non-negotiated language priority, using * position of language on the Accept-Language: * header, if present, else LanguagePriority * directive order. * * When we do the variant checking for best variant, we use language * quality first, and if a tie, language_index next (this only applies * when _not_ using the RVSA/1.0 algorithm). If using the RVSA/1.0 * algorithm, lang_index is never used. * * set_language_quality() calls find_lang_index() and find_default_index() * to set lang_index. */ static int find_lang_index(apr_array_header_t *accept_langs, char *lang) { const char **alang; int i; if (!lang || !accept_langs) { return -1; } alang = (const char **) accept_langs->elts; for (i = 0; i < accept_langs->nelts; ++i) { if (!strncmp(lang, *alang, strlen(*alang))) { return i; } alang += (accept_langs->elt_size / sizeof(char*)); } return -1; } /* set_default_lang_quality() sets the quality we apply to variants * which have no language assigned to them. If none of the variants * have a language, we are not negotiating on language, so all are * acceptable, and we set the default q value to 1.0. However if * some of the variants have languages, we set this default to 0.0001. * The value of this default will be applied to all variants with * no explicit language -- which will have the effect of making them * acceptable, but only if no variants with an explicit language * are acceptable. The default q value set here is assigned to variants * with no language type in set_language_quality(). * * Note that if using the RVSA/1.0 algorithm, we don't use this * fiddle. */ static void set_default_lang_quality(negotiation_state *neg) { var_rec *avail_recs = (var_rec *) neg->avail_vars->elts; int j; if (!neg->dont_fiddle_headers) { for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; if (variant->content_languages && variant->content_languages->nelts) { neg->default_lang_quality = 0.0001f; return; } } } neg->default_lang_quality = 1.0f; } /* Set the language_quality value in the variant record. Also * assigns lang_index for ForceLanguagePriority. * * To find the language_quality value, we look for the 'q' value * of the 'best' matching language on the Accept-Language * header. The 'best' match is the language on Accept-Language * header which matches the language of this variant either fully, * or as far as the prefix marker (-). If two or more languages * match, use the longest string from the Accept-Language header * (see HTTP/1.1 [14.4]) * * When a variant has multiple languages, we find the 'best' * match for each variant language tag as above, then select the * one with the highest q value. Because both the accept-header * and variant can have multiple languages, we now have a hairy * loop-within-a-loop here. * * If the variant has no language and we have no Accept-Language * items, leave the quality at 1.0 and return. * * If the variant has no language, we use the default as set by * set_default_lang_quality() (1.0 if we are not negotiating on * language, 0.001 if we are). * * Following the setting of the language quality, we drop through to * set the old 'lang_index'. This is set based on either the order * of the languages on the Accept-Language header, or the * order on the LanguagePriority directive. This is only used * in the negotiation if the language qualities tie. */ static void set_language_quality(negotiation_state *neg, var_rec *variant) { int forcepriority = neg->conf->forcelangpriority; if (forcepriority == FLP_UNDEF) { forcepriority = FLP_DEFAULT; } if (!variant->content_languages || !variant->content_languages->nelts) { /* This variant has no content-language, so use the default * quality factor for variants with no content-language * (previously set by set_default_lang_quality()). * Leave the factor alone (it remains at 1.0) when we may not fiddle * with the headers. */ if (!neg->dont_fiddle_headers) { variant->lang_quality = neg->default_lang_quality; } if (!neg->accept_langs) { return; /* no accept-language header */ } return; } else { /* Variant has one (or more) languages. Look for the best * match. We do this by going through each language on the * variant description looking for a match on the * Accept-Language header. The best match is the longest * matching language on the header. The final result is the * best q value from all the languages on the variant * description. */ if (!neg->accept_langs) { /* no accept-language header makes the variant indefinite */ variant->definite = 0; } else { /* There is an accept-language with 0 or more items */ accept_rec *accs = (accept_rec *) neg->accept_langs->elts; accept_rec *best = NULL, *star = NULL; accept_rec *bestthistag; char *lang, *p; float fiddle_q = 0.0f; int any_match_on_star = 0; int i, j; apr_size_t alen, longest_lang_range_len; for (j = 0; j < variant->content_languages->nelts; ++j) { p = NULL; bestthistag = NULL; longest_lang_range_len = 0; alen = 0; /* lang is the variant's language-tag, which is the one * we are allowed to use the prefix of in HTTP/1.1 */ lang = ((char **) (variant->content_languages->elts))[j]; /* now find the best (i.e. longest) matching * Accept-Language header language. We put the best match * for this tag in bestthistag. We cannot update the * overall best (based on q value) because the best match * for this tag is the longest language item on the accept * header, not necessarily the highest q. */ for (i = 0; i < neg->accept_langs->nelts; ++i) { if (!strcmp(accs[i].name, "*")) { if (!star) { star = &accs[i]; } continue; } /* Find language. We match if either the variant * language tag exactly matches the language range * from the accept header, or a prefix of the variant * language tag up to a '-' character matches the * whole of the language range in the Accept-Language * header. Note that HTTP/1.x allows any number of * '-' characters in a tag or range, currently only * tags with zero or one '-' characters are defined * for general use (see rfc1766). * * We only use language range in the Accept-Language * header the best match for the variant language tag * if it is longer than the previous best match. */ alen = strlen(accs[i].name); if ((strlen(lang) >= alen) && !strncmp(lang, accs[i].name, alen) && ((lang[alen] == 0) || (lang[alen] == '-')) ) { if (alen > longest_lang_range_len) { longest_lang_range_len = alen; bestthistag = &accs[i]; } } if (!bestthistag && !neg->dont_fiddle_headers) { /* The next bit is a fiddle. Some browsers might * be configured to send more specific language * ranges than desirable. For example, an * Accept-Language of en-US should never match * variants with languages en or en-GB. But US * English speakers might pick en-US as their * language choice. So this fiddle checks if the * language range has a prefix, and if so, it * matches variants which match that prefix with a * priority of 0.001. So a request for en-US would * match variants of types en and en-GB, but at * much lower priority than matches of en-US * directly, or of any other language listed on * the Accept-Language header. Note that this * fiddle does not handle multi-level prefixes. */ if ((p = strchr(accs[i].name, '-'))) { int plen = p - accs[i].name; if (!strncmp(lang, accs[i].name, plen)) { fiddle_q = 0.001f; } } } } /* Finished looking at Accept-Language headers, the best * (longest) match is in bestthistag, or NULL if no match */ if (!best || (bestthistag && bestthistag->quality > best->quality)) { best = bestthistag; } /* See if the tag matches on a * in the Accept-Language * header. If so, record this fact for later use */ if (!bestthistag && star) { any_match_on_star = 1; } } /* If one of the language tags of the variant matched on *, we * need to see if its q is better than that of any non-* match * on any other tag of the variant. If so the * match takes * precedence and the overall match is not definite. */ if ( any_match_on_star && ((best && star->quality > best->quality) || (!best)) ) { best = star; variant->definite = 0; } variant->lang_quality = best ? best->quality : fiddle_q; } } /* Handle the ForceDefaultLanguage overrides, based on the best match * to LanguagePriority order. The best match is the lowest index of * any LanguagePriority match. */ if (((forcepriority & FLP_PREFER) && (variant->lang_index < 0)) || ((forcepriority & FLP_FALLBACK) && !variant->lang_quality)) { int bestidx = -1; int j; for (j = 0; j < variant->content_languages->nelts; ++j) { /* lang is the variant's language-tag, which is the one * we are allowed to use the prefix of in HTTP/1.1 */ char *lang = ((char **) (variant->content_languages->elts))[j]; int idx = -1; /* If we wish to fallback or * we use our own LanguagePriority index. */ idx = find_lang_index(neg->conf->language_priority, lang); if ((idx >= 0) && ((bestidx == -1) || (idx < bestidx))) { bestidx = idx; } } if (bestidx >= 0) { if (variant->lang_quality) { if (forcepriority & FLP_PREFER) { variant->lang_index = bestidx; } } else { if (forcepriority & FLP_FALLBACK) { variant->lang_index = bestidx; variant->lang_quality = .0001f; variant->definite = 0; } } } } return; } /* Determining the content length --- if the map didn't tell us, * we have to do a stat() and remember for next time. */ static apr_off_t find_content_length(negotiation_state *neg, var_rec *variant) { apr_finfo_t statb; if (variant->bytes < 0) { if ( variant->sub_req && (variant->sub_req->finfo.valid & APR_FINFO_SIZE)) { variant->bytes = variant->sub_req->finfo.size; } else { char *fullname = ap_make_full_path(neg->pool, neg->dir_name, variant->file_name); if (apr_stat(&statb, fullname, APR_FINFO_SIZE, neg->pool) == APR_SUCCESS) { variant->bytes = statb.size; } } } return variant->bytes; } /* For a given variant, find the best matching Accept: header * and assign the Accept: header's quality value to the * mime_type_quality field of the variant, for later use in * determining the best matching variant. */ static void set_accept_quality(negotiation_state *neg, var_rec *variant) { int i; accept_rec *accept_recs; float q = 0.0f; int q_definite = 1; /* if no Accept: header, leave quality alone (will * remain at the default value of 1) * * XXX: This if is currently never true because of the effect of * maybe_add_default_accepts(). */ if (!neg->accepts) { if (variant->mime_type && *variant->mime_type) variant->definite = 0; return; } accept_recs = (accept_rec *) neg->accepts->elts; /* * Go through each of the ranges on the Accept: header, * looking for the 'best' match with this variant's * content-type. We use the best match's quality * value (from the Accept: header) for this variant's * mime_type_quality field. * * The best match is determined like this: * type/type is better than type/ * is better than * / * * if match is type/type, use the level mime param if available */ for (i = 0; i < neg->accepts->nelts; ++i) { accept_rec *type = &accept_recs[i]; int prev_mime_stars; prev_mime_stars = variant->mime_stars; if (!mime_match(type, variant)) { continue; /* didn't match the content type at all */ } else { /* did match - see if there were less or more stars than * in previous match */ if (prev_mime_stars == variant->mime_stars) { continue; /* more stars => not as good a match */ } } /* If we are allowed to mess with the q-values * and have no explicit q= parameters in the accept header, * make wildcards very low, so we have a low chance * of ending up with them if there's something better. */ if (!neg->dont_fiddle_headers && !neg->accept_q && variant->mime_stars == 1) { q = 0.01f; } else if (!neg->dont_fiddle_headers && !neg->accept_q && variant->mime_stars == 2) { q = 0.02f; } else { q = type->quality; } q_definite = (variant->mime_stars == 3); } variant->mime_type_quality = q; variant->definite = variant->definite && q_definite; } /* For a given variant, find the 'q' value of the charset given * on the Accept-Charset line. If no charsets are listed, * assume value of '1'. */ static void set_charset_quality(negotiation_state *neg, var_rec *variant) { int i; accept_rec *accept_recs; const char *charset = variant->content_charset; accept_rec *star = NULL; /* if no Accept-Charset: header, leave quality alone (will * remain at the default value of 1) */ if (!neg->accept_charsets) { if (charset && *charset) variant->definite = 0; return; } accept_recs = (accept_rec *) neg->accept_charsets->elts; if (charset == NULL || !*charset) { /* Charset of variant not known */ /* if not a text / * type, leave quality alone */ if (!(!strncmp(variant->mime_type, "text/", 5) || !strcmp(variant->mime_type, INCLUDES_MAGIC_TYPE) || !strcmp(variant->mime_type, INCLUDES_MAGIC_TYPE3) )) return; /* Don't go guessing if we are in strict header mode, * e.g. when running the rvsa, as any guess won't be reflected * in the variant list or content-location headers. */ if (neg->dont_fiddle_headers) return; charset = "iso-8859-1"; /* The default charset for HTTP text types */ } /* * Go through each of the items on the Accept-Charset header, * looking for a match with this variant's charset. If none * match, charset is unacceptable, so set quality to 0. */ for (i = 0; i < neg->accept_charsets->nelts; ++i) { accept_rec *type = &accept_recs[i]; if (!strcmp(type->name, charset)) { variant->charset_quality = type->quality; return; } else if (strcmp(type->name, "*") == 0) { star = type; } } /* No explicit match */ if (star) { variant->charset_quality = star->quality; variant->definite = 0; return; } /* If this variant is in charset iso-8859-1, the default is 1.0 */ if (strcmp(charset, "iso-8859-1") == 0) { variant->charset_quality = 1.0f; } else { variant->charset_quality = 0.0f; } } /* is_identity_encoding is included for back-compat, but does anyone * use 7bit, 8bin or binary in their var files?? */ static int is_identity_encoding(const char *enc) { return (!enc || !enc[0] || !strcmp(enc, "7bit") || !strcmp(enc, "8bit") || !strcmp(enc, "binary")); } /* * set_encoding_quality determines whether the encoding for a particular * variant is acceptable for the user-agent. * * The rules for encoding are that if the user-agent does not supply * any Accept-Encoding header, then all encodings are allowed but a * variant with no encoding should be preferred. * If there is an empty Accept-Encoding header, then no encodings are * acceptable. If there is a non-empty Accept-Encoding header, then * any of the listed encodings are acceptable, as well as no encoding * unless the "identity" encoding is specifically excluded. */ static void set_encoding_quality(negotiation_state *neg, var_rec *variant) { accept_rec *accept_recs; const char *enc = variant->content_encoding; accept_rec *star = NULL; float value_if_not_found = 0.0f; int i; if (!neg->accept_encodings) { /* We had no Accept-Encoding header, assume that all * encodings are acceptable with a low quality, * but we prefer no encoding if available. */ if (!enc || is_identity_encoding(enc)) variant->encoding_quality = 1.0f; else variant->encoding_quality = 0.5f; return; } if (!enc || is_identity_encoding(enc)) { enc = "identity"; value_if_not_found = 0.0001f; } accept_recs = (accept_rec *) neg->accept_encodings->elts; /* Go through each of the encodings on the Accept-Encoding: header, * looking for a match with our encoding. x- prefixes are ignored. */ if (enc[0] == 'x' && enc[1] == '-') { enc += 2; } for (i = 0; i < neg->accept_encodings->nelts; ++i) { char *name = accept_recs[i].name; if (name[0] == 'x' && name[1] == '-') { name += 2; } if (!strcmp(name, enc)) { variant->encoding_quality = accept_recs[i].quality; return; } if (strcmp(name, "*") == 0) { star = &accept_recs[i]; } } /* No explicit match */ if (star) { variant->encoding_quality = star->quality; return; } /* Encoding not found on Accept-Encoding: header, so it is * _not_ acceptable unless it is the identity (no encoding) */ variant->encoding_quality = value_if_not_found; } /************************************************************* * Possible results of the variant selection algorithm */ enum algorithm_results { alg_choice = 1, /* choose variant */ alg_list /* list variants */ }; /* Below is the 'best_match' function. It returns an int, which has * one of the two values alg_choice or alg_list, which give the result * of the variant selection algorithm. alg_list means that no best * variant was found by the algorithm, alg_choice means that a best * variant was found and should be returned. The list/choice * terminology comes from TCN (rfc2295), but is used in a more generic * way here. The best variant is returned in *pbest. best_match has * two possible algorithms for determining the best variant: the * RVSA/1.0 algorithm (from RFC2296), and the standard Apache * algorithm. These are split out into separate functions * (is_variant_better_rvsa() and is_variant_better()). Selection of * one is through the neg->use_rvsa flag. * * The call to best_match also creates full information, including * language, charset, etc quality for _every_ variant. This is needed * for generating a correct Vary header, and can be used for the * Alternates header, the human-readable list responses and 406 errors. */ /* Firstly, the RVSA/1.0 (HTTP Remote Variant Selection Algorithm * v1.0) from rfc2296. This is the algorithm that goes together with * transparent content negotiation (TCN). */ static int is_variant_better_rvsa(negotiation_state *neg, var_rec *variant, var_rec *best, float *p_bestq) { float bestq = *p_bestq, q; /* TCN does not cover negotiation on content-encoding. For now, * we ignore the encoding unless it was explicitly excluded. */ if (variant->encoding_quality == 0.0f) return 0; q = variant->mime_type_quality * variant->source_quality * variant->charset_quality * variant->lang_quality; /* RFC 2296 calls for the result to be rounded to 5 decimal places, * but we don't do that because it serves no useful purpose other * than to ensure that a remote algorithm operates on the same * precision as ours. That is silly, since what we obviously want * is for the algorithm to operate on the best available precision * regardless of who runs it. Since the above calculation may * result in significant variance at 1e-12, rounding would be bogus. */ #ifdef NEG_DEBUG ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "Variant: file=%s type=%s lang=%s sourceq=%1.3f " "mimeq=%1.3f langq=%1.3f charq=%1.3f encq=%1.3f " "q=%1.5f definite=%d", (variant->file_name ? variant->file_name : ""), (variant->mime_type ? variant->mime_type : ""), (variant->content_languages ? apr_array_pstrcat(neg->pool, variant->content_languages, ',') : ""), variant->source_quality, variant->mime_type_quality, variant->lang_quality, variant->charset_quality, variant->encoding_quality, q, variant->definite); #endif if (q <= 0.0f) { return 0; } if (q > bestq) { *p_bestq = q; return 1; } if (q == bestq) { /* If the best variant's encoding is of lesser quality than * this variant, then we prefer this variant */ if (variant->encoding_quality > best->encoding_quality) { *p_bestq = q; return 1; } } return 0; } /* Negotiation algorithm as used by previous versions of Apache * (just about). */ static int is_variant_better(negotiation_state *neg, var_rec *variant, var_rec *best, float *p_bestq) { float bestq = *p_bestq, q; int levcmp; /* For non-transparent negotiation, server can choose how * to handle the negotiation. We'll use the following in * order: content-type, language, content-type level, charset, * content encoding, content length. * * For each check, we have three possible outcomes: * This variant is worse than current best: return 0 * This variant is better than the current best: * assign this variant's q to *p_bestq, and return 1 * This variant is just as desirable as the current best: * drop through to the next test. * * This code is written in this long-winded way to allow future * customisation, either by the addition of additional * checks, or to allow the order of the checks to be determined * by configuration options (e.g. we might prefer to check * language quality _before_ content type). */ /* First though, eliminate this variant if it is not * acceptable by type, charset, encoding or language. */ #ifdef NEG_DEBUG ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, "Variant: file=%s type=%s lang=%s sourceq=%1.3f " "mimeq=%1.3f langq=%1.3f langidx=%d charq=%1.3f encq=%1.3f ", (variant->file_name ? variant->file_name : ""), (variant->mime_type ? variant->mime_type : ""), (variant->content_languages ? apr_array_pstrcat(neg->pool, variant->content_languages, ',') : ""), variant->source_quality, variant->mime_type_quality, variant->lang_quality, variant->lang_index, variant->charset_quality, variant->encoding_quality); #endif if (variant->encoding_quality == 0.0f || variant->lang_quality == 0.0f || variant->source_quality == 0.0f || variant->charset_quality == 0.0f || variant->mime_type_quality == 0.0f) { return 0; /* don't consider unacceptables */ } q = variant->mime_type_quality * variant->source_quality; if (q == 0.0 || q < bestq) { return 0; } if (q > bestq || !best) { *p_bestq = q; return 1; } /* language */ if (variant->lang_quality < best->lang_quality) { return 0; } if (variant->lang_quality > best->lang_quality) { *p_bestq = q; return 1; } /* if language qualities were equal, try the LanguagePriority stuff */ if (best->lang_index != -1 && (variant->lang_index == -1 || variant->lang_index > best->lang_index)) { return 0; } if (variant->lang_index != -1 && (best->lang_index == -1 || variant->lang_index < best->lang_index)) { *p_bestq = q; return 1; } /* content-type level (sometimes used with text/html, though we * support it on other types too) */ levcmp = level_cmp(variant, best); if (levcmp == -1) { return 0; } if (levcmp == 1) { *p_bestq = q; return 1; } /* charset */ if (variant->charset_quality < best->charset_quality) { return 0; } /* If the best variant's charset is ISO-8859-1 and this variant has * the same charset quality, then we prefer this variant */ if (variant->charset_quality > best->charset_quality || ((variant->content_charset != NULL && *variant->content_charset != '\0' && strcmp(variant->content_charset, "iso-8859-1") != 0) && (best->content_charset == NULL || *best->content_charset == '\0' || strcmp(best->content_charset, "iso-8859-1") == 0))) { *p_bestq = q; return 1; } /* Prefer the highest value for encoding_quality. */ if (variant->encoding_quality < best->encoding_quality) { return 0; } if (variant->encoding_quality > best->encoding_quality) { *p_bestq = q; return 1; } /* content length if all else equal */ if (find_content_length(neg, variant) >= find_content_length(neg, best)) { return 0; } /* ok, to get here means every thing turned out equal, except * we have a shorter content length, so use this variant */ *p_bestq = q; return 1; } /* figure out, whether a variant is in a specific language * it returns also false, if the variant has no language. */ static int variant_has_language(var_rec *variant, const char *lang) { int j, max; /* fast exit */ if ( !lang || !variant->content_languages || !(max = variant->content_languages->nelts)) { return 0; } for (j = 0; j < max; ++j) { if (!strcmp(lang, ((char **) (variant->content_languages->elts))[j])) { return 1; } } return 0; } /* check for environment variables 'no-gzip' and * 'gzip-only-text/html' to get a behaviour similiar * to mod_deflate */ static int discard_variant_by_env(var_rec *variant, int discard) { if ( is_identity_encoding(variant->content_encoding) || !strcmp(variant->content_encoding, "identity")) { return 0; } return ( (discard == DISCARD_ALL_ENCODINGS) || (discard == DISCARD_ALL_BUT_HTML && (!variant->mime_type || strncmp(variant->mime_type, "text/html", 9)))); } static int best_match(negotiation_state *neg, var_rec **pbest) { int j; var_rec *best; float bestq = 0.0f; enum algorithm_results algorithm_result; int may_discard = 0; var_rec *avail_recs = (var_rec *) neg->avail_vars->elts; /* fetch request dependent variables * prefer-language: prefer a certain language. */ const char *preferred_language = apr_table_get(neg->r->subprocess_env, "prefer-language"); /* no-gzip: do not send encoded documents */ if (apr_table_get(neg->r->subprocess_env, "no-gzip")) { may_discard = DISCARD_ALL_ENCODINGS; } /* gzip-only-text/html: send encoded documents only * if they are text/html. (no-gzip has a higher priority). */ else { const char *env_value = apr_table_get(neg->r->subprocess_env, "gzip-only-text/html"); if (env_value && !strcmp(env_value, "1")) { may_discard = DISCARD_ALL_BUT_HTML; } } set_default_lang_quality(neg); /* * Find the 'best' variant * We run the loop possibly twice: if "prefer-language" * environment variable is set but we did not find an appropriate * best variant. In that case forget the preferred language and * negotiate over all variants. */ do { best = NULL; for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; /* if this variant is encoded somehow and there are special * variables set, we do not negotiate it. see above. */ if ( may_discard && discard_variant_by_env(variant, may_discard)) { continue; } /* if a language is preferred, but the current variant * is not in that language, then drop it for now */ if ( preferred_language && !variant_has_language(variant, preferred_language)) { continue; } /* Find all the relevant 'quality' values from the * Accept... headers, and store in the variant. This also * prepares for sending an Alternates header etc so we need to * do it even if we do not actually plan to find a best * variant. */ set_accept_quality(neg, variant); /* accept the preferred language, even when it's not listed within * the Accept-Language header */ if (preferred_language) { variant->lang_quality = 1.0f; variant->definite = 1; } else { set_language_quality(neg, variant); } set_encoding_quality(neg, variant); set_charset_quality(neg, variant); /* Only do variant selection if we may actually choose a * variant for the client */ if (neg->may_choose) { /* Now find out if this variant is better than the current * best, either using the RVSA/1.0 algorithm, or Apache's * internal server-driven algorithm. Presumably other * server-driven algorithms are possible, and could be * implemented here. */ if (neg->use_rvsa) { if (is_variant_better_rvsa(neg, variant, best, &bestq)) { best = variant; } } else { if (is_variant_better(neg, variant, best, &bestq)) { best = variant; } } } } /* We now either have a best variant, or no best variant */ if (neg->use_rvsa) { /* calculate result for RVSA/1.0 algorithm: * only a choice response if the best variant has q>0 * and is definite */ algorithm_result = (best && best->definite) && (bestq > 0) ? alg_choice : alg_list; } else { /* calculate result for Apache negotiation algorithm */ algorithm_result = bestq > 0 ? alg_choice : alg_list; } /* run the loop again, if the "prefer-language" got no clear result */ if (preferred_language && (!best || algorithm_result != alg_choice)) { preferred_language = NULL; continue; } break; } while (1); /* Returning a choice response with a non-neighboring variant is a * protocol security error in TCN (see rfc2295). We do *not* * verify here that the variant and URI are neighbors, even though * we may return alg_choice. We depend on the environment (the * caller) to only declare the resource transparently negotiable if * all variants are neighbors. */ *pbest = best; return algorithm_result; } /* Sets response headers for a negotiated response. * neg->is_transparent determines whether a transparently negotiated * response or a plain `server driven negotiation' response is * created. Applicable headers are Alternates, Vary, and TCN. * * The Vary header we create is sometimes longer than is required for * the correct caching of negotiated results by HTTP/1.1 caches. For * example if we have 3 variants x.html, x.ps.en and x.ps.nl, and if * the Accept: header assigns a 0 quality to .ps, then the results of * the two server-side negotiation algorithms we currently implement * will never depend on Accept-Language so we could return `Vary: * negotiate, accept' instead of the longer 'Vary: negotiate, accept, * accept-language' which the code below will return. A routine for * computing the exact minimal Vary header would be a huge pain to code * and maintain though, especially because we need to take all possible * twiddles in the server-side negotiation algorithms into account. */ static void set_neg_headers(request_rec *r, negotiation_state *neg, int alg_result) { apr_table_t *hdrs; var_rec *avail_recs = (var_rec *) neg->avail_vars->elts; const char *sample_type = NULL; const char *sample_language = NULL; const char *sample_encoding = NULL; const char *sample_charset = NULL; char *lang; char *qstr; apr_off_t len; apr_array_header_t *arr; int max_vlist_array = (neg->avail_vars->nelts * 21); int first_variant = 1; int vary_by_type = 0; int vary_by_language = 0; int vary_by_charset = 0; int vary_by_encoding = 0; int j; /* In order to avoid O(n^2) memory copies in building Alternates, * we preallocate a apr_table_t with the maximum substrings possible, * fill it with the variant list, and then concatenate the entire array. * Note that if you change the number of substrings pushed, you also * need to change the calculation of max_vlist_array above. */ if (neg->send_alternates && neg->avail_vars->nelts) arr = apr_array_make(r->pool, max_vlist_array, sizeof(char *)); else arr = NULL; /* Put headers into err_headers_out, since send_http_header() * outputs both headers_out and err_headers_out. */ hdrs = r->err_headers_out; for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; if (variant->content_languages && variant->content_languages->nelts) { lang = apr_array_pstrcat(r->pool, variant->content_languages, ','); } else { lang = NULL; } /* Calculate Vary by looking for any difference between variants */ if (first_variant) { sample_type = variant->mime_type; sample_charset = variant->content_charset; sample_language = lang; sample_encoding = variant->content_encoding; } else { if (!vary_by_type && strcmp(sample_type ? sample_type : "", variant->mime_type ? variant->mime_type : "")) { vary_by_type = 1; } if (!vary_by_charset && strcmp(sample_charset ? sample_charset : "", variant->content_charset ? variant->content_charset : "")) { vary_by_charset = 1; } if (!vary_by_language && strcmp(sample_language ? sample_language : "", lang ? lang : "")) { vary_by_language = 1; } if (!vary_by_encoding && strcmp(sample_encoding ? sample_encoding : "", variant->content_encoding ? variant->content_encoding : "")) { vary_by_encoding = 1; } } first_variant = 0; if (!neg->send_alternates) continue; /* Generate the string components for this Alternates entry */ *((const char **) apr_array_push(arr)) = "{\""; *((const char **) apr_array_push(arr)) = variant->file_name; *((const char **) apr_array_push(arr)) = "\" "; qstr = (char *) apr_palloc(r->pool, 6); apr_snprintf(qstr, 6, "%1.3f", variant->source_quality); /* Strip trailing zeros (saves those valuable network bytes) */ if (qstr[4] == '0') { qstr[4] = '\0'; if (qstr[3] == '0') { qstr[3] = '\0'; if (qstr[2] == '0') { qstr[1] = '\0'; } } } *((const char **) apr_array_push(arr)) = qstr; if (variant->mime_type && *variant->mime_type) { *((const char **) apr_array_push(arr)) = " {type "; *((const char **) apr_array_push(arr)) = variant->mime_type; *((const char **) apr_array_push(arr)) = "}"; } if (variant->content_charset && *variant->content_charset) { *((const char **) apr_array_push(arr)) = " {charset "; *((const char **) apr_array_push(arr)) = variant->content_charset; *((const char **) apr_array_push(arr)) = "}"; } if (lang) { *((const char **) apr_array_push(arr)) = " {language "; *((const char **) apr_array_push(arr)) = lang; *((const char **) apr_array_push(arr)) = "}"; } if (variant->content_encoding && *variant->content_encoding) { /* Strictly speaking, this is non-standard, but so is TCN */ *((const char **) apr_array_push(arr)) = " {encoding "; *((const char **) apr_array_push(arr)) = variant->content_encoding; *((const char **) apr_array_push(arr)) = "}"; } /* Note that the Alternates specification (in rfc2295) does * not require that we include {length x}, so we could omit it * if determining the length is too expensive. We currently * always include it though. * * If the variant is a CGI script, find_content_length would * return the length of the script, not the output it * produces, so we check for the presence of a handler and if * there is one we don't add a length. * * XXX: TODO: This check does not detect a CGI script if we * get the variant from a type map. This needs to be fixed * (without breaking things if the type map specifies a * content-length, which currently leads to the correct result). */ if (!(variant->sub_req && variant->sub_req->handler) && (len = find_content_length(neg, variant)) >= 0) { *((const char **) apr_array_push(arr)) = " {length "; *((const char **) apr_array_push(arr)) = apr_off_t_toa(r->pool, len); *((const char **) apr_array_push(arr)) = "}"; } *((const char **) apr_array_push(arr)) = "}"; *((const char **) apr_array_push(arr)) = ", "; /* trimmed below */ } if (neg->send_alternates && neg->avail_vars->nelts) { arr->nelts--; /* remove last comma */ apr_table_mergen(hdrs, "Alternates", apr_array_pstrcat(r->pool, arr, '\0')); } if (neg->is_transparent || vary_by_type || vary_by_language || vary_by_language || vary_by_charset || vary_by_encoding) { apr_table_mergen(hdrs, "Vary", 2 + apr_pstrcat(r->pool, neg->is_transparent ? ", negotiate" : "", vary_by_type ? ", accept" : "", vary_by_language ? ", accept-language" : "", vary_by_charset ? ", accept-charset" : "", vary_by_encoding ? ", accept-encoding" : "", NULL)); } if (neg->is_transparent) { /* Create TCN response header */ apr_table_setn(hdrs, "TCN", alg_result == alg_list ? "list" : "choice"); } } /********************************************************************** * * Return an HTML list of variants. This is output as part of the * choice response or 406 status body. */ static char *make_variant_list(request_rec *r, negotiation_state *neg) { apr_array_header_t *arr; int i; int max_vlist_array = (neg->avail_vars->nelts * 15) + 2; /* In order to avoid O(n^2) memory copies in building the list, * we preallocate a apr_table_t with the maximum substrings possible, * fill it with the variant list, and then concatenate the entire array. */ arr = apr_array_make(r->pool, max_vlist_array, sizeof(char *)); *((const char **) apr_array_push(arr)) = "Available variants:\n<ul>\n"; for (i = 0; i < neg->avail_vars->nelts; ++i) { var_rec *variant = &((var_rec *) neg->avail_vars->elts)[i]; const char *filename = variant->file_name ? variant->file_name : ""; apr_array_header_t *languages = variant->content_languages; const char *description = variant->description ? variant->description : ""; /* The format isn't very neat, and it would be nice to make * the tags human readable (eg replace 'language en' with 'English'). * Note that if you change the number of substrings pushed, you also * need to change the calculation of max_vlist_array above. */ *((const char **) apr_array_push(arr)) = "<li><a href=\""; *((const char **) apr_array_push(arr)) = filename; *((const char **) apr_array_push(arr)) = "\">"; *((const char **) apr_array_push(arr)) = filename; *((const char **) apr_array_push(arr)) = "</a> "; *((const char **) apr_array_push(arr)) = description; if (variant->mime_type && *variant->mime_type) { *((const char **) apr_array_push(arr)) = ", type "; *((const char **) apr_array_push(arr)) = variant->mime_type; } if (languages && languages->nelts) { *((const char **) apr_array_push(arr)) = ", language "; *((const char **) apr_array_push(arr)) = apr_array_pstrcat(r->pool, languages, ','); } if (variant->content_charset && *variant->content_charset) { *((const char **) apr_array_push(arr)) = ", charset "; *((const char **) apr_array_push(arr)) = variant->content_charset; } if (variant->content_encoding) { *((const char **) apr_array_push(arr)) = ", encoding "; *((const char **) apr_array_push(arr)) = variant->content_encoding; } *((const char **) apr_array_push(arr)) = "</li>\n"; } *((const char **) apr_array_push(arr)) = "</ul>\n"; return apr_array_pstrcat(r->pool, arr, '\0'); } static void store_variant_list(request_rec *r, negotiation_state *neg) { if (r->main == NULL) { apr_table_setn(r->notes, "variant-list", make_variant_list(r, neg)); } else { apr_table_setn(r->main->notes, "variant-list", make_variant_list(r->main, neg)); } } /* Called if we got a "Choice" response from the variant selection algorithm. * It checks the result of the chosen variant to see if it * is itself negotiated (if so, return error HTTP_VARIANT_ALSO_VARIES). * Otherwise, add the appropriate headers to the current response. */ static int setup_choice_response(request_rec *r, negotiation_state *neg, var_rec *variant) { request_rec *sub_req; const char *sub_vary; if (!variant->sub_req) { int status; sub_req = ap_sub_req_lookup_file(variant->file_name, r, NULL); status = sub_req->status; if (status != HTTP_OK && !apr_table_get(sub_req->err_headers_out, "TCN")) { ap_destroy_sub_req(sub_req); return status; } variant->sub_req = sub_req; } else { sub_req = variant->sub_req; } /* The variant selection algorithm told us to return a "Choice" * response. This is the normal variant response, with * some extra headers. First, ensure that the chosen * variant did or will not itself engage in transparent negotiation. * If not, set the appropriate headers, and fall through to * the normal variant handling */ /* This catches the error that a transparent type map selects a * transparent multiviews resource as the best variant. * * XXX: We do not signal an error if a transparent type map * selects a _non_transparent multiviews resource as the best * variant, because we can generate a legal negotiation response * in this case. In this case, the vlist_validator of the * nontransparent subrequest will be lost however. This could * lead to cases in which a change in the set of variants or the * negotiation algorithm of the nontransparent resource is never * propagated up to a HTTP/1.1 cache which interprets Vary. To be * completely on the safe side we should return HTTP_VARIANT_ALSO_VARIES * for this type of recursive negotiation too. */ if (neg->is_transparent && apr_table_get(sub_req->err_headers_out, "TCN")) { return HTTP_VARIANT_ALSO_VARIES; } /* This catches the error that a transparent type map recursively * selects, as the best variant, another type map which itself * causes transparent negotiation to be done. * * XXX: Actually, we catch this error by catching all cases of * type map recursion. There are some borderline recursive type * map arrangements which would not produce transparent * negotiation protocol errors or lack of cache propagation * problems, but such arrangements are very hard to detect at this * point in the control flow, so we do not bother to single them * out. * * Recursive type maps imply a recursive arrangement of negotiated * resources which is visible to outside clients, and this is not * supported by the transparent negotiation caching protocols, so * if we are to have generic support for recursive type maps, we * have to create some configuration setting which makes all type * maps non-transparent when recursion is enabled. Also, if we * want recursive type map support which ensures propagation of * type map changes into HTTP/1.1 caches that handle Vary, we * would have to extend the current mechanism for generating * variant list validators. */ if (sub_req->handler && strcmp(sub_req->handler, "type-map") == 0) { return HTTP_VARIANT_ALSO_VARIES; } /* This adds an appropriate Variant-Vary header if the subrequest * is a multiviews resource. * * XXX: TODO: Note that this does _not_ handle any Vary header * returned by a CGI if sub_req is a CGI script, because we don't * see that Vary header yet at this point in the control flow. * This won't cause any cache consistency problems _unless_ the * CGI script also returns a Cache-Control header marking the * response as cachable. This needs to be fixed, also there are * problems if a CGI returns an Etag header which also need to be * fixed. */ if ((sub_vary = apr_table_get(sub_req->err_headers_out, "Vary")) != NULL) { apr_table_setn(r->err_headers_out, "Variant-Vary", sub_vary); /* Move the subreq Vary header into the main request to * prevent having two Vary headers in the response, which * would be legal but strange. */ apr_table_setn(r->err_headers_out, "Vary", sub_vary); apr_table_unset(sub_req->err_headers_out, "Vary"); } apr_table_setn(r->err_headers_out, "Content-Location", apr_pstrdup(r->pool, variant->file_name)); set_neg_headers(r, neg, alg_choice); /* add Alternates and Vary */ /* Still to do by caller: add Expires */ return 0; } /**************************************************************** * * Executive... */ static int do_negotiation(request_rec *r, negotiation_state *neg, var_rec **bestp, int prefer_scripts) { var_rec *avail_recs = (var_rec *) neg->avail_vars->elts; int alg_result; /* result of variant selection algorithm */ int res; int j; /* Decide if resource is transparently negotiable */ /* GET or HEAD? (HEAD has same method number as GET) */ if (r->method_number == M_GET) { /* maybe this should be configurable, see also the comment * about recursive type maps in setup_choice_response() */ neg->is_transparent = 1; /* We can't be transparent if we are a map file in the middle * of the request URI. */ if (r->path_info && *r->path_info) neg->is_transparent = 0; for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; /* We can't be transparent, because of internal * assumptions in best_match(), if there is a * non-neighboring variant. We can have a non-neighboring * variant when processing a type map. */ if (ap_strchr_c(variant->file_name, '/')) neg->is_transparent = 0; /* We can't be transparent, because of the behavior * of variant typemap bodies. */ if (variant->body) { neg->is_transparent = 0; } } } if (neg->is_transparent) { parse_negotiate_header(r, neg); } else { /* configure negotiation on non-transparent resource */ neg->may_choose = 1; } maybe_add_default_accepts(neg, prefer_scripts); alg_result = best_match(neg, bestp); /* alg_result is one of * alg_choice: a best variant is chosen * alg_list: no best variant is chosen */ if (alg_result == alg_list) { /* send a list response or HTTP_NOT_ACCEPTABLE error response */ neg->send_alternates = 1; /* always include Alternates header */ set_neg_headers(r, neg, alg_result); store_variant_list(r, neg); if (neg->is_transparent && neg->ua_supports_trans) { /* XXX todo: expires? cachability? */ /* Some HTTP/1.0 clients are known to choke when they get * a 300 (multiple choices) response without a Location * header. However the 300 code response we are are about * to generate will only reach 1.0 clients which support * transparent negotiation, and they should be OK. The * response should never reach older 1.0 clients, even if * we have CacheNegotiatedDocs enabled, because no 1.0 * proxy cache (we know of) will cache and return 300 * responses (they certainly won't if they conform to the * HTTP/1.0 specification). */ return HTTP_MULTIPLE_CHOICES; } if (!*bestp) { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, "no acceptable variant: %s", r->filename); return HTTP_NOT_ACCEPTABLE; } } /* Variant selection chose a variant */ /* XXX todo: merge the two cases in the if statement below */ if (neg->is_transparent) { if ((res = setup_choice_response(r, neg, *bestp)) != 0) { return res; /* return if error */ } } else { set_neg_headers(r, neg, alg_result); } /* Make sure caching works - Vary should handle HTTP/1.1, but for * HTTP/1.0, we can't allow caching at all. */ /* XXX: Note that we only set r->no_cache to 1, which causes * Expires: <now> to be added, when responding to a HTTP/1.0 * client. If we return the response to a 1.1 client, we do not * add Expires <now>, because doing so would degrade 1.1 cache * performance by preventing re-use of the response without prior * revalidation. On the other hand, if the 1.1 client is a proxy * which was itself contacted by a 1.0 client, or a proxy cache * which can be contacted later by 1.0 clients, then we currently * rely on this 1.1 proxy to add the Expires: <now> when it * forwards the response. * * XXX: TODO: Find out if the 1.1 spec requires proxies and * tunnels to add Expires: <now> when forwarding the response to * 1.0 clients. I (kh) recall it is rather vague on this point. * Testing actual 1.1 proxy implementations would also be nice. If * Expires: <now> is not added by proxies then we need to always * include Expires: <now> ourselves to ensure correct caching, but * this would degrade HTTP/1.1 cache efficiency unless we also add * Cache-Control: max-age=N, which we currently don't. * * Roy: No, we are not going to screw over HTTP future just to * ensure that people who can't be bothered to upgrade their * clients will always receive perfect server-side negotiation. * Hell, those clients are sending bogus accept headers anyway. * * Manual setting of cache-control/expires always overrides this * automated kluge, on purpose. */ if ((!do_cache_negotiated_docs(r->server) && (r->proto_num < HTTP_VERSION(1,1))) && neg->count_multiviews_variants != 1) { r->no_cache = 1; } return OK; } static int handle_map_file(request_rec *r) { negotiation_state *neg; apr_file_t *map; var_rec *best; int res; char *udir; const char *new_req; if(strcmp(r->handler,MAP_FILE_MAGIC_TYPE) && strcmp(r->handler,"type-map")) return DECLINED; neg = parse_accept_headers(r); if ((res = read_type_map(&map, neg, r))) { return res; } res = do_negotiation(r, neg, &best, 0); if (res != 0) return res; if (best->body) { conn_rec *c = r->connection; apr_bucket_brigade *bb; apr_bucket *e; ap_allow_standard_methods(r, REPLACE_ALLOW, M_GET, M_OPTIONS, M_POST, -1); /* XXX: ? * if (r->method_number == M_OPTIONS) { * return ap_send_http_options(r); *} */ if (r->method_number != M_GET && r->method_number != M_POST) { return HTTP_METHOD_NOT_ALLOWED; } /* ### These may be implemented by adding some 'extra' info * of the file offset onto the etag * ap_update_mtime(r, r->finfo.mtime); * ap_set_last_modified(r); * ap_set_etag(r); */ apr_table_setn(r->headers_out, "Accept-Ranges", "bytes"); ap_set_content_length(r, best->bytes); /* set MIME type and charset as negotiated */ if (best->mime_type && *best->mime_type) { if (best->content_charset && *best->content_charset) { ap_set_content_type(r, apr_pstrcat(r->pool, best->mime_type, "; charset=", best->content_charset, NULL)); } else { ap_set_content_type(r, apr_pstrdup(r->pool, best->mime_type)); } } /* set Content-language(s) as negotiated */ if (best->content_languages && best->content_languages->nelts) { r->content_languages = apr_array_copy(r->pool, best->content_languages); } /* set Content-Encoding as negotiated */ if (best->content_encoding && *best->content_encoding) { r->content_encoding = apr_pstrdup(r->pool, best->content_encoding); } if ((res = ap_meets_conditions(r)) != OK) { return res; } if ((res = ap_discard_request_body(r)) != OK) { return res; } bb = apr_brigade_create(r->pool, c->bucket_alloc); e = apr_bucket_file_create(map, best->body, (apr_size_t)best->bytes, r->pool, c->bucket_alloc); APR_BRIGADE_INSERT_TAIL(bb, e); e = apr_bucket_eos_create(c->bucket_alloc); APR_BRIGADE_INSERT_TAIL(bb, e); return ap_pass_brigade(r->output_filters, bb); } if (r->path_info && *r->path_info) { /* remove any path_info from the end of the uri before trying * to change the filename. r->path_info from the original * request is passed along on the redirect. */ r->uri[ap_find_path_info(r->uri, r->path_info)] = '\0'; } udir = ap_make_dirstr_parent(r->pool, r->uri); udir = ap_escape_uri(r->pool, udir); if (r->args) { if (r->path_info) { new_req = apr_pstrcat(r->pool, udir, best->file_name, r->path_info, "?", r->args, NULL); } else { new_req = apr_pstrcat(r->pool, udir, best->file_name, "?", r->args, NULL); } } else { new_req = apr_pstrcat(r->pool, udir, best->file_name, r->path_info, NULL); } ap_internal_redirect(new_req, r); return OK; } static int handle_multi(request_rec *r) { negotiation_state *neg; var_rec *best, *avail_recs; request_rec *sub_req; int res; int j; if (r->finfo.filetype != APR_NOFILE || !(ap_allow_options(r) & OPT_MULTI)) { return DECLINED; } neg = parse_accept_headers(r); if ((res = read_types_multi(neg))) { return_from_multi: /* free all allocated memory from subrequests */ avail_recs = (var_rec *) neg->avail_vars->elts; for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; if (variant->sub_req) { ap_destroy_sub_req(variant->sub_req); } } return res; } if (neg->avail_vars->nelts == 0) { return DECLINED; } res = do_negotiation(r, neg, &best, (r->method_number != M_GET) || r->args || (r->path_info && *r->path_info)); if (res != 0) goto return_from_multi; if (!(sub_req = best->sub_req)) { /* We got this out of a map file, so we don't actually have * a sub_req structure yet. Get one now. */ sub_req = ap_sub_req_lookup_file(best->file_name, r, NULL); if (sub_req->status != HTTP_OK) { res = sub_req->status; ap_destroy_sub_req(sub_req); goto return_from_multi; } } /* now do a "fast redirect" ... promotes the sub_req into the main req */ ap_internal_fast_redirect(sub_req, r); /* give no advise for time on this subrequest. Perhaps we * should tally the last mtime amoung all variants, and date * the most recent, but that could confuse the proxies. */ r->mtime = 0; /* clean up all but our favorite variant, since that sub_req * is now merged into the main request! */ avail_recs = (var_rec *) neg->avail_vars->elts; for (j = 0; j < neg->avail_vars->nelts; ++j) { var_rec *variant = &avail_recs[j]; if (variant != best && variant->sub_req) { ap_destroy_sub_req(variant->sub_req); } } return OK; } /********************************************************************** * There is a problem with content-encoding, as some clients send and * expect an x- token (e.g. x-gzip) while others expect the plain token * (i.e. gzip). To try and deal with this as best as possible we do * the following: if the client sent an Accept-Encoding header and it * contains a plain token corresponding to the content encoding of the * response, then set content encoding using the plain token. Else if * the A-E header contains the x- token use the x- token in the C-E * header. Else don't do anything. * * Note that if no A-E header was sent, or it does not contain a token * compatible with the final content encoding, then the token in the * C-E header will be whatever was specified in the AddEncoding * directive. */ static int fix_encoding(request_rec *r) { const char *enc = r->content_encoding; char *x_enc = NULL; apr_array_header_t *accept_encodings; accept_rec *accept_recs; int i; if (!enc || !*enc) { return DECLINED; } if (enc[0] == 'x' && enc[1] == '-') { enc += 2; } if ((accept_encodings = do_header_line(r->pool, apr_table_get(r->headers_in, "Accept-Encoding"))) == NULL) { return DECLINED; } accept_recs = (accept_rec *) accept_encodings->elts; for (i = 0; i < accept_encodings->nelts; ++i) { char *name = accept_recs[i].name; if (!strcmp(name, enc)) { r->content_encoding = name; return OK; } if (name[0] == 'x' && name[1] == '-' && !strcmp(name+2, enc)) { x_enc = name; } } if (x_enc) { r->content_encoding = x_enc; return OK; } return DECLINED; } static void register_hooks(apr_pool_t *p) { ap_hook_fixups(fix_encoding,NULL,NULL,APR_HOOK_MIDDLE); ap_hook_type_checker(handle_multi,NULL,NULL,APR_HOOK_FIRST); ap_hook_handler(handle_map_file,NULL,NULL,APR_HOOK_MIDDLE); } module AP_MODULE_DECLARE_DATA negotiation_module = { STANDARD20_MODULE_STUFF, create_neg_dir_config, /* dir config creator */ merge_neg_dir_configs, /* dir merger --- default is to override */ NULL, /* server config */ NULL, /* merge server config */ negotiation_cmds, /* command apr_table_t */ register_hooks /* register hooks */ };
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