Fix failure to re-create config when it is bad (due to attempt to find a link

[dcpomatic.git] / src / lib / config.cc

diff --git a/src/lib/config.cc b/src/lib/config.cc
index e61eea3a6f89f7cd916be30b9cb8a54aa595dc95..9dd6f638e7c6e16ba29545f942dc1388ed887378 100644 (file)
--- a/src/lib/config.cc
+++ b/src/lib/config.cc
@@ -32,6 +32,7 @@
 #include "film.h"
 #include "dkdm_wrapper.h"
 #include "compose.hpp"
+#include "crypto.h"
 #include <dcp/raw_convert.h>
 #include <dcp/name_format.h>
 #include <dcp/certificate_chain.h>
@@ -61,6 +62,7 @@ using boost::shared_ptr;
 using boost::optional;
 using boost::dynamic_pointer_cast;
 using boost::algorithm::trim;
+using boost::shared_array;
 using dcp::raw_convert;
 
 Config* Config::_instance = 0;
@@ -435,7 +437,19 @@ try
                BOOST_FOREACH (cxml::NodePtr i, decryption->node_children ("Certificate")) {
                        c->add (dcp::Certificate (i->content ()));
                }
-               c->set_key (decryption->string_child ("PrivateKey"));
+               optional<string> key = decryption->optional_string_child ("PrivateKey");
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+               if (key) {
+                       c->set_key (*key);
+               } else {
+                       dcp::Data encrypted_key (path("private"));
+                       dcp::Data iv (path("iv"));
+                       c->set_key (dcpomatic::decrypt (encrypted_key, key_from_uuid(), iv));
+               }
+#else
+               DCPOMATIC_ASSERT (key);
+               c->set_key (*key);
+#endif
                _decryption_chain = c;
        } else {
                _decryption_chain = create_certificate_chain ();
@@ -599,6 +613,19 @@ Config::write () const
        write_cinemas ();
 }
 
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+/* Make up a key from the machine UUID */
+dcp::Data
+Config::key_from_uuid () const
+{
+       dcp::Data key (dcpomatic::crypto_key_length());
+       memset (key.data().get(), 0, key.size());
+       string const magic = command_and_read ("dcpomatic2_uuid");
+       strncpy ((char *) key.data().get(), magic.c_str(), dcpomatic::crypto_key_length());
+       return key;
+}
+#endif
+
 void
 Config::write_config () const
 {
@@ -771,18 +798,7 @@ Config::write_config () const
        BOOST_FOREACH (dcp::Certificate const & i, _signer_chain->unordered()) {
                signer->add_child("Certificate")->add_child_text (i.certificate (true));
        }
-#ifdef DCPOMATIC_SWAROOP
-       FILE* f = fopen_boost (path("private"), "wb");
-       if (!f) {
-               throw FileError ("Could not open file for writing", path("private"));
-       }
-       shared_array<uint8_t> iv = dcpomatic::random_iv ();
-       dcp::Data encrypted_key = dcpomatic::encrypt (_signer_chain->key().get(), key, iv);
-       fwrite (encrypted_key.data().get(), encrypted_key.data().size(), 1, f);
-       fclose (f);
-#else  
        signer->add_child("PrivateKey")->add_child_text (_signer_chain->key().get ());
-#endif 
 
        /* [XML] Decryption Certificate chain and private key to use when decrypting KDMs */
        xmlpp::Element* decryption = root->add_child ("Decryption");
@@ -790,7 +806,14 @@ Config::write_config () const
        BOOST_FOREACH (dcp::Certificate const & i, _decryption_chain->unordered()) {
                decryption->add_child("Certificate")->add_child_text (i.certificate (true));
        }
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+       dcp::Data iv = dcpomatic::random_iv ();
+       dcp::Data encrypted_key = dcpomatic::encrypt (_decryption_chain->key().get(), key_from_uuid(), iv);
+       encrypted_key.write (path("private"));
+       iv.write (path("iv"));
+#else
        decryption->add_child("PrivateKey")->add_child_text (_decryption_chain->key().get ());
+#endif
 
        /* [XML] History Filename of DCP to present in the <guilabel>File</guilabel> menu of the GUI; there can be more than one
           of these tags.
@@ -959,17 +982,15 @@ Config::write_config () const
 
        try {
                string const s = doc.write_to_string_formatted ();
-               boost::filesystem::path const cf = config_file ();
-               FILE* f = fopen_boost (cf, "w");
+               boost::filesystem::path tmp (string(config_file().string()).append(".tmp"));
+               FILE* f = fopen_boost (tmp, "w");
                if (!f) {
-                       throw FileError (_("Could not open file for writing"), cf);
-               }
-               size_t const w = fwrite (s.c_str(), 1, s.length(), f);
-               if (w != s.length()) {
-                       fclose (f);
-                       throw FileError (_("Could not write whole file"), cf);
+                       throw FileError (_("Could not open file for writing"), tmp);
                }
+               checked_fwrite (s.c_str(), s.length(), f, tmp);
                fclose (f);
+               boost::filesystem::remove (config_file());
+               boost::filesystem::rename (tmp, config_file());
        } catch (xmlpp::exception& e) {
                string s = e.what ();
                trim (s);
@@ -989,7 +1010,9 @@ Config::write_cinemas () const
        }
 
        try {
-               doc.write_to_file_formatted (_cinemas_file.string ());
+               doc.write_to_file_formatted (_cinemas_file.string() + ".tmp");
+               boost::filesystem::remove (_cinemas_file);
+               boost::filesystem::rename (_cinemas_file.string() + ".tmp", _cinemas_file);
        } catch (xmlpp::exception& e) {
                string s = e.what ();
                trim (s);
@@ -1214,10 +1237,16 @@ Config::config_file ()
        }
 
        /* See if there's a link */
-       f.read_file (main);
-       optional<string> link = f.optional_string_child("Link");
-       if (link) {
-               return *link;
+       try {
+               f.read_file (main);
+               optional<string> link = f.optional_string_child("Link");
+               if (link) {
+                       return *link;
+               }
+       } catch (xmlpp::exception& e) {
+               /* There as a problem reading the main configuration file,
+                  so there can't be a link.
+               */
        }
 
        return main;