first cut on XRI resolver

 This commit adds openid service resolver that does discovery using XRI (proxy
 only), Yadis protocol and html-based discovery. It uses expat as xml parsing
 engine, which makes it a bit more strict about html it receives, but I think
 failing to discover links in *severely* broken html is better than
 misdetecting links, hidden in comments or such.

 This is highly experimental code and needs more thoughts and testing.

 Thanks everyone pushing me towards this development. Namely Joseph, John,
 Gen.

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 12 insertions, 4 deletions

diff --git a/lib/util.cc b/lib/util.cc
index ac70938..69d37b5 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -1,295 +1,303 @@
 #include <errno.h>
 #include <cassert>
 #include <cctype>
 #include <cstring>
 #include <vector>
 #include <string>
 #include <stack>
 #include <openssl/bio.h>
 #include <openssl/evp.h>
 #include <curl/curl.h>
 #include "opkele/util.h"
 #include "opkele/exception.h"
 
 namespace opkele {
     using namespace std;
 
     namespace util {
 
         /*
          * base64
          */
         string encode_base64(const void *data,size_t length) {
             BIO *b64 = 0, *bmem = 0;
             try {
                 b64 = BIO_new(BIO_f_base64());
                 if(!b64)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() base64 encoder");
                 BIO_set_flags(b64,BIO_FLAGS_BASE64_NO_NL);
                 bmem = BIO_new(BIO_s_mem());
                 BIO_set_flags(b64,BIO_CLOSE);
                 if(!bmem)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() memory buffer");
                 BIO_push(b64,bmem);
                 if(((size_t)BIO_write(b64,data,length))!=length)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_write()");
                 if(BIO_flush(b64)!=1)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_flush()");
                 char *rvd;
                 long rvl = BIO_get_mem_data(bmem,&rvd);
                 string rv(rvd,rvl);
                 BIO_free_all(b64);
                 return rv;
             }catch(...) {
                 if(b64) BIO_free_all(b64);
                 throw;
             }
         }
 
         void decode_base64(const string& data,vector<unsigned char>& rv) {
             BIO *b64 = 0, *bmem = 0;
             rv.clear();
             try {
                 bmem = BIO_new_mem_buf((void*)data.data(),data.size());
                 if(!bmem)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new_mem_buf()");
                 b64 = BIO_new(BIO_f_base64());
                 if(!b64)
                     throw exception_openssl(OPKELE_CP_ "failed to BIO_new() base64 decoder");
                 BIO_set_flags(b64,BIO_FLAGS_BASE64_NO_NL);
                 BIO_push(b64,bmem);
                 unsigned char tmp[512];
                 size_t rb = 0;
                 while((rb=BIO_read(b64,tmp,sizeof(tmp)))>0)
                     rv.insert(rv.end(),tmp,&tmp[rb]);
                 BIO_free_all(b64);
             }catch(...) {
                 if(b64) BIO_free_all(b64);
                 throw;
             }
         }
 
         /*
          * big numerics
          */
 
         BIGNUM *base64_to_bignum(const string& b64) {
             vector<unsigned char> bin;
             decode_base64(b64,bin);
             BIGNUM *rv = BN_bin2bn(&(bin.front()),bin.size(),0);
             if(!rv)
                 throw failed_conversion(OPKELE_CP_ "failed to BN_bin2bn()");
             return rv;
         }
 
         BIGNUM *dec_to_bignum(const string& dec) {
             BIGNUM *rv = 0;
             if(!BN_dec2bn(&rv,dec.c_str()))
                 throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
             return rv;
         }
 
         string bignum_to_base64(const BIGNUM *bn) {
             vector<unsigned char> bin(BN_num_bytes(bn)+1);
             unsigned char *binptr = &(bin.front())+1;
             int l = BN_bn2bin(bn,binptr);
             if(l && (*binptr)&0x80){
                 (*(--binptr)) = 0; ++l;
             }
             return encode_base64(binptr,l);
         }
 
         /*
          * w3c times
          */
 
         string time_to_w3c(time_t t) {
             struct tm tm_t;
             if(!gmtime_r(&t,&tm_t))
                 throw failed_conversion(OPKELE_CP_ "failed to BN_dec2bn()");
             char rv[25];
             if(!strftime(rv,sizeof(rv)-1,"%Y-%m-%dT%H:%M:%SZ",&tm_t))
                 throw failed_conversion(OPKELE_CP_ "failed to strftime()");
             return rv;
         }
 
         time_t w3c_to_time(const string& w) {
             struct tm tm_t;
             memset(&tm_t,0,sizeof(tm_t));
             if(
                     sscanf(
                         w.c_str(),
                         "%04d-%02d-%02dT%02d:%02d:%02dZ",
                         &tm_t.tm_year,&tm_t.tm_mon,&tm_t.tm_mday,
                         &tm_t.tm_hour,&tm_t.tm_min,&tm_t.tm_sec
                     ) != 6 )
                 throw failed_conversion(OPKELE_CP_ "failed to sscanf()");
             tm_t.tm_mon--;
             tm_t.tm_year-=1900;
             time_t rv = mktime(&tm_t);
             if(rv==(time_t)-1)
                 throw failed_conversion(OPKELE_CP_ "failed to mktime()");
             return rv;
         }
 
         /*
          *
          */
 
         string url_encode(const string& str) {
             char * t = curl_escape(str.c_str(),str.length());
             if(!t)
                 throw failed_conversion(OPKELE_CP_ "failed to curl_escape()");
             string rv(t);
             curl_free(t);
             return rv;
         }
 
         string long_to_string(long l) {
             char rv[32];
             int r=snprintf(rv,sizeof(rv),"%ld",l);
             if(r<0 || r>=(int)sizeof(rv))
                 throw failed_conversion(OPKELE_CP_ "failed to snprintf()");
             return rv;
         }
 
         long string_to_long(const string& s) {
             char *endptr = 0;
             long rv = strtol(s.c_str(),&endptr,10);
             if((!endptr) || endptr==s.c_str())
                 throw failed_conversion(OPKELE_CP_ "failed to strtol()");
             return rv;
         }
 
         /*
          * Normalize URL according to the rules, described in rfc 3986, section 6
          *
          * - uppercase hext triplets (e.g. %ab -> %AB)
          * - lowercase scheme and host
          * - decode %-encoded characters, specified as unreserved in rfc 3986, section 2.3,
          *   that is - [:alpha:][:digit:]._~-
          * - remove dot segments
          * - remove empty and default ports
          * - if there's no path component, add '/'
          */
          string rfc_3986_normalize_uri(const string& uri) {
+             static const char *whitespace = " \t\r\n";
              string rv;
-             string::size_type colon = uri.find(':');
+             string::size_type ns = uri.find_first_not_of(whitespace);
+             if(ns==string::npos)
+                 throw bad_input(OPKELE_CP_ "Can't normalize empty URI");
+             string::size_type colon = uri.find(':',ns);
              if(colon==string::npos)
                  throw bad_input(OPKELE_CP_ "No scheme specified in URI");
              transform(
-                     uri.begin(), uri.begin()+colon+1,
+                     uri.begin()+ns, uri.begin()+colon+1,
                      back_inserter(rv), ::tolower );
              bool s;
              if(rv=="http:")
                  s = false;
              else if(rv=="https:")
                  s = true;
+#ifndef NDEBUG
+             else if(rv=="file:")
+                 s = false;
+#endif /* XXX: or try to make tests work some other way */
              else
                  throw not_implemented(OPKELE_CP_ "Only http(s) URIs can be normalized here");
-             string::size_type ul = uri.length();
+             string::size_type ul = uri.find_last_not_of(whitespace)+1;
              if(ul <= (colon+3))
                  throw bad_input(OPKELE_CP_ "Unexpected end of URI being normalized encountered");
              if(uri[colon+1]!='/' || uri[colon+2]!='/')
                  throw bad_input(OPKELE_CP_ "Unexpected input in URI being normalized after scheme component");
              rv += "//";
              string::size_type interesting = uri.find_first_of(":/#?",colon+3);
              if(interesting==string::npos) {
                  transform(
-                         uri.begin()+colon+3,uri.end(),
+                         uri.begin()+colon+3,uri.begin()+ul,
                          back_inserter(rv), ::tolower );
                  rv += '/'; return rv;
              }
              transform(
                      uri.begin()+colon+3,uri.begin()+interesting,
                      back_inserter(rv), ::tolower );
              bool qf = false;
              char ic = uri[interesting];
              if(ic==':') {
                  string::size_type ni = uri.find_first_of("/#?%",interesting+1);
                  const char *nptr = uri.data()+interesting+1;
                  char *eptr = 0;
                  long port = strtol(nptr,&eptr,10);
                  if( (port>0) && (port<65535) && port!=(s?443:80) ) {
                      char tmp[6];
                      snprintf(tmp,sizeof(tmp),"%ld",port);
                      rv += ':'; rv += tmp;
                  }
                  if(ni==string::npos) {
                      rv += '/'; return rv;
                  }
                  interesting = ni;
              }else if(ic!='/') {
                  rv += '/'; rv += ic;
                  qf = true;
                  ++interesting;
              }
              string::size_type n = interesting;
              char tmp[3] = { 0,0,0 };
              stack<string::size_type> psegs; psegs.push(rv.length());
              string pseg;
              for(;n<ul;) {
                  string::size_type unsafe = uri.find_first_of(qf?"%":"%/?#",n);
                  if(unsafe==string::npos) {
                      pseg.append(uri,n,ul-n-1); n = ul-1;
                  }else{
                      pseg.append(uri,n,unsafe-n);
                      n = unsafe;
                  }
                  char c = uri[n++];
                  if(c=='%') {
                      if((n+1)>=ul)
                          throw bad_input(OPKELE_CP_ "Unexpected end of URI encountered while parsing percent-encoded character");
                      tmp[0] = uri[n++];
                      tmp[1] = uri[n++];
                      if(!( isxdigit(tmp[0]) && isxdigit(tmp[1]) ))
                          throw bad_input(OPKELE_CP_ "Invalid percent-encoded character in URI being normalized");
                      int cc = strtol(tmp,0,16);
                      if( isalpha(cc) || isdigit(cc) || strchr("._~-",cc) )
                          pseg += cc;
                      else{
                          pseg += '%';
                          pseg += toupper(tmp[0]); pseg += toupper(tmp[1]);
                      }
                  }else if(qf) {
                      rv += pseg; rv += c;
                      pseg.clear();
                  }else if(n>=ul || strchr("?/#",c)) {
                      if(pseg.empty() || pseg==".") {
                      }else if(pseg=="..") {
                          if(psegs.size()>1) {
                              rv.resize(psegs.top()); psegs.pop();
                          }
                      }else{
                          psegs.push(rv.length());
                          if(c!='/') {
                              pseg += c;
                              qf = true;
                          }
                          rv += '/'; rv += pseg;
                      }
                      if(c=='/' && (n>=ul || strchr("?#",uri[n])) ) {
                          rv += '/';
                          if(n<ul)
                              qf = true;
                      }else if(strchr("?#",c)) {
                          if(psegs.size()==1 && psegs.top()==rv.length())
                              rv += '/';
                          if(pseg.empty())
                              rv += c;
                          qf = true;
                      }
                      pseg.clear();
                  }else{
                      pseg += c;
                  }
              }
              if(!pseg.empty()) {
                  rv += '/'; rv += pseg;
              }
              return rv;
          }
 
     }
 
 }