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Windows specific: Transactional saving of PrusaSlicer.ini to ensure

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that configuration could be recovered in the case PrusaSlicer.ini
is corrupted during saving. The config is first written into a temp file
marked with a MD5 checksum. Once the file is saved, it is
copied to a backup file first, then moved to PrusaSlicer.ini.

When loading PrusaSlicer.ini fails, the backup file will be loaded
instead, however only if its MD5 checksum is valid.

The following "Fixes" comments are for github triggers. We implemented
a workaround, not a fix, we don't actually know how the data corruption
happens and why. Most likely the "Move file" Windows API is not atomic
and if PrusaSlicer crashes on another thread while moving the file,
PrusaSlicer.ini will only be partially saved, with the rest of the file
filled with nulls. We did not "fix" the issue, we just hope that our
workaround will help in majority of cases.

Fixes prusaslicer wont open 2.3 windows 10 #5812
Fixes Won't Open - Windows 10 #4915
Fixes PrusaSlicer Crashes upon opening with "'=' character not found in
line error" #2438
Fixes Fails to open on blank slic3r.ini %user%\AppData\Roaming\Slic3rPE
This commit is contained in:
Vojtech Bubnik 2021-06-25 16:44:06 +02:00
parent 2359d8f2eb
commit e06ec9d4bf
2 changed files with 145 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

148
src/libslic3r/AppConfig.cpp
View File

@ -3,6 +3,7 @@
#include "AppConfig.hpp"
#include "Exception.hpp"
#include "Thread.hpp"
#include "format.hpp"
#include <utility>
#include <vector>
@ -16,9 +17,13 @@
#include <boost/property_tree/ptree_fwd.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/format/format_fwd.hpp>
#include <boost/log/trivial.hpp>
//#include <wx/string.h>
//#include "I18N.hpp"
#ifdef WIN32
//FIXME replace the two following includes with <boost/md5.hpp> after it becomes mainstream.
#include <boost/uuid/detail/md5.hpp>
#include <boost/algorithm/hex.hpp>
#endif
namespace Slic3r {
@ -164,15 +169,103 @@ void AppConfig::set_defaults()
erase("", "object_settings_size");
}
#ifdef WIN32
static std::string appconfig_md5_hash_line(const std::string_view data)
{
//FIXME replace the two following includes with <boost/md5.hpp> after it becomes mainstream.
// return boost::md5(data).hex_str_value();
// boost::uuids::detail::md5 is an internal namespace thus it may change in the future.
// Also this implementation is not the fastest, it was designed for short blocks of text.
using boost::uuids::detail::md5;
md5 md5_hash;
// unsigned int[4], 128 bits
md5::digest_type md5_digest{};
std::string md5_digest_str;
md5_hash.process_bytes(data.data(), data.size());
md5_hash.get_digest(md5_digest);
boost::algorithm::hex(md5_digest, md5_digest + std::size(md5_digest), std::back_inserter(md5_digest_str));
// MD5 hash is 32 HEX digits long.
assert(md5_digest_str.size() == 32);
// This line will be emited at the end of the file.
return "# MD5 checksum " + md5_digest_str + "\n";
};
// Assume that the last line with the comment inside the config file contains a checksum and that the user didn't modify the config file.
static bool verify_config_file_checksum(boost::nowide::ifstream &ifs)
{
auto read_whole_config_file = [&ifs]() -> std::string {
std::stringstream ss;
ss << ifs.rdbuf();
return ss.str();
};
ifs.seekg(0, boost::nowide::ifstream::beg);
std::string whole_config = read_whole_config_file();
// The checksum should be on the last line in the config file.
if (size_t last_comment_pos = whole_config.find_last_of('#'); last_comment_pos != std::string::npos) {
// Split read config into two parts, one with checksum, and the second part is part with configuration from the checksum was computed.
// Verify existence and validity of the MD5 checksum line at the end of the file.
// When the checksum isn't found, the checksum was not saved correctly, it was removed or it is an older config file without the checksum.
// If the checksum is incorrect, then the file was either not saved correctly or modified.
if (std::string_view(whole_config.c_str() + last_comment_pos, whole_config.size() - last_comment_pos) == appconfig_md5_hash_line({ whole_config.data(), last_comment_pos }))
return true;
}
return false;
}
#endif
std::string AppConfig::load()
{
// 1) Read the complete config file into a boost::property_tree.
namespace pt = boost::property_tree;
pt::ptree tree;
boost::nowide::ifstream ifs(AppConfig::config_path());
boost::nowide::ifstream ifs;
bool recovered = false;
try {
ifs.open(AppConfig::config_path());
#ifdef WIN32
// Verify the checksum of the config file without taking just for debugging purpose.
if (!verify_config_file_checksum(ifs))
BOOST_LOG_TRIVIAL(info) << "The configuration file " << AppConfig::config_path() <<
" has a wrong MD5 checksum or the checksum is missing. This may indicate a file corruption or a harmless user edit.";
ifs.seekg(0, boost::nowide::ifstream::beg);
#endif
pt::read_ini(ifs, tree);
} catch (pt::ptree_error& ex) {
#ifdef WIN32
// The configuration file is corrupted, try replacing it with the backup configuration.
ifs.close();
std::string backup_path = (boost::format("%1%.bak") % AppConfig::config_path()).str();
if (boost::filesystem::exists(backup_path)) {
// Compute checksum of the configuration backup file and try to load configuration from it when the checksum is correct.
boost::nowide::ifstream backup_ifs(backup_path);
if (!verify_config_file_checksum(backup_ifs)) {
BOOST_LOG_TRIVIAL(error) << format("Both \"%1%\" and \"%2%\" are corrupted. It isn't possible to restore configuration from the backup.", AppConfig::config_path(), backup_path);
backup_ifs.close();
boost::filesystem::remove(backup_path);
} else if (std::string error_message; copy_file(backup_path, AppConfig::config_path(), error_message, false) != SUCCESS) {
BOOST_LOG_TRIVIAL(error) << format("Configuration file \"%1%\" is corrupted. Failed to restore from backup \"%2%\": %3%", AppConfig::config_path(), backup_path, error_message);
backup_ifs.close();
boost::filesystem::remove(backup_path);
} else {
BOOST_LOG_TRIVIAL(info) << format("Configuration file \"%1%\" was corrupted. It has been succesfully restored from the backup \"%2%\".", AppConfig::config_path(), backup_path);
// Try parse configuration file after restore from backup.
try {
ifs.open(AppConfig::config_path());
pt::read_ini(ifs, tree);
recovered = true;
} catch (pt::ptree_error& ex) {
BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\" after it has been restored from backup: %2%", AppConfig::config_path(), ex.what());
}
}
} else
#endif // WIN32
BOOST_LOG_TRIVIAL(info) << format("Failed to parse configuration file \"%1%\": %2%", AppConfig::config_path(), ex.what());
if (! recovered) {
// Report the initial error of parsing PrusaSlicer.ini.
// Error while parsing config file. We'll customize the error message and rethrow to be displayed.
// ! But to avoid the use of _utf8 (related to use of wxWidgets)
// we will rethrow this exception from the place of load() call, if returned value wouldn't be empty
@ -184,6 +277,7 @@ std::string AppConfig::load()
*/
return ex.what();
}
}
// 2) Parse the property_tree, extract the sections and key / value pairs.
for (const auto &section : tree) {
@ -259,22 +353,21 @@ void AppConfig::save()
const auto path = config_path();
std::string path_pid = (boost::format("%1%.%2%") % path % get_current_pid()).str();
boost::nowide::ofstream c;
c.open(path_pid, std::ios::out | std::ios::trunc);
std::stringstream config_ss;
if (m_mode == EAppMode::Editor)
c << "# " << Slic3r::header_slic3r_generated() << std::endl;
config_ss << "# " << Slic3r::header_slic3r_generated() << std::endl;
else
c << "# " << Slic3r::header_gcodeviewer_generated() << std::endl;
config_ss << "# " << Slic3r::header_gcodeviewer_generated() << std::endl;
// Make sure the "no" category is written first.
for (const std::pair<std::string, std::string> &kvp : m_storage[""])
c << kvp.first << " = " << kvp.second << std::endl;
for (const auto& kvp : m_storage[""])
config_ss << kvp.first << " = " << kvp.second << std::endl;
// Write the other categories.
for (const auto category : m_storage) {
if (category.first.empty())
continue;
c << std::endl << "[" << category.first << "]" << std::endl;
for (const std::pair<std::string, std::string> &kvp : category.second)
c << kvp.first << " = " << kvp.second << std::endl;
config_ss << std::endl << "[" << category.first << "]" << std::endl;
for (const auto& kvp : category.second)
config_ss << kvp.first << " = " << kvp.second << std::endl;
}
// Write vendor sections
for (const auto &vendor : m_vendors) {
@ -282,17 +375,42 @@ void AppConfig::save()
for (const auto &model : vendor.second) { size_sum += model.second.size(); }
if (size_sum == 0) { continue; }
c << std::endl << "[" << VENDOR_PREFIX << vendor.first << "]" << std::endl;
config_ss << std::endl << "[" << VENDOR_PREFIX << vendor.first << "]" << std::endl;
for (const auto &model : vendor.second) {
if (model.second.size() == 0) { continue; }
if (model.second.empty()) { continue; }
const std::vector<std::string> variants(model.second.begin(), model.second.end());
const auto escaped = escape_strings_cstyle(variants);
c << MODEL_PREFIX << model.first << " = " << escaped << std::endl;
config_ss << MODEL_PREFIX << model.first << " = " << escaped << std::endl;
}
}
// One empty line before the MD5 sum.
config_ss << std::endl;
std::string config_str = config_ss.str();
boost::nowide::ofstream c;
c.open(path_pid, std::ios::out | std::ios::trunc);
c << config_str;
#ifdef WIN32
// WIN32 specific: The final "rename_file()" call is not safe in case of an application crash, there is no atomic "rename file" API
// provided by Windows (sic!). Therefore we save a MD5 checksum to be able to verify file corruption. In addition,
// we save the config file into a backup first before moving it to the final destination.
c << appconfig_md5_hash_line(config_str);
#endif
c.close();
#ifdef WIN32
// Make a backup of the configuration file before copying it to the final destination.
std::string error_message;
std::string backup_path = (boost::format("%1%.bak") % path).str();
// Copy configuration file with PID suffix into the configuration file with "bak" suffix.
if (copy_file(path_pid, backup_path, error_message, false) != SUCCESS)
BOOST_LOG_TRIVIAL(error) << "Copying from " << path_pid << " to " << backup_path << " failed. Failed to create a backup configuration.";
#endif
// Rename the config atomically.
// On Windows, the rename is likely NOT atomic, thus it may fail if PrusaSlicer crashes on another thread in the meanwhile.
// To cope with that, we already made a backup of the config on Windows.
rename_file(path_pid, path);
m_dirty = false;
}