Christopher M. Punches
0291e61fd8
Installation records what a module reports about itself. dpm_install_module opens a module once, writes its version and description to a .meta file in /var/lib/dpm/metadata/, and records the alternate names it declared in modules.aliases beside it. dpm_uninstall_module removes both, leaving the module file in place. dpm_list_modules reads those records and opens no module. A module with no record lists with a version of <uninstalled> and still loads when a caller names it. An unreadable or absent metadata directory costs the listing its detail and costs nothing else. Aliases give a module alternate names, declared through the new dpm_module_aliases contract symbol or added with dpm_add_module_alias. A name is recorded once: one already serving as an alias, or belonging to an installed module, is refused rather than repointed. dpm_require matches a name against the installed modules, then the alias table, then the module path. The metadata directory is a fifth override field and the -M flag, and [modules] metadata in core.conf. The test suite is four binaries covering context, modules, records, and aliases, each a ctest case of its own, alongside the CLI cases.
129 lines
4.6 KiB
C++
129 lines
4.6 KiB
C++
/**
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* @file metadata.hpp
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* @brief Module records: what libdpm-core.so knows without loading a module
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*
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* @copyright Copyright (c) 2026 SILO GROUP LLC
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* @author Chris Punches <chris.punches@silogroup.org>
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*
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* Part of the Dark Horse Linux Package Manager (DPM)
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <map>
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#include <string>
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struct dpm_ctx;
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/**
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* @brief The records one module's .meta file carries
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*
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* Written when a module is installed, from what the module itself
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* reported at that moment. A listing reports these values, so a listing
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* needs to open no module.
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*/
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struct dpm_module_meta_records {
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/** Basename of the module file these records describe. */
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std::string module_file;
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/** Version the module reported when it was installed. */
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std::string version;
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/** Description the module reported when it was installed. */
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std::string description;
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};
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namespace dpm_core {
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/**
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* @brief Reads a flat key/value file from the metadata directory
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*
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* The format every file in that directory uses: one `key = value`
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* per line, '#' and ';' opening a comment, and every key and value
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* trimmed. A line carrying no '=' is skipped, so a malformed line
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* costs that line and no more.
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*
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* @param path The file to read
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* @param out Receives the pairs the file carried
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* @return true when the file was opened; false when it was not
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*/
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bool md_read_key_value_file(const std::string& path,
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std::map<std::string, std::string>& out);
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/**
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* @brief Writes a flat key/value file into the metadata directory
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*
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* Creates the directory when it is absent, and replaces the file's
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* whole contents.
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*
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* @param path The file to write
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* @param values The pairs to write, one per line
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* @param reason Receives the failure reason when the write fails
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* @return true on success
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*/
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bool md_write_key_value_file(
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const std::string& path,
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const std::map<std::string, std::string>& values,
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std::string& reason);
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/**
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* @brief Reads every module record in a context's metadata directory
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*
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* Each .meta file becomes one set of records named after the file
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* without its extension. A missing or unreadable directory leaves
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* the context holding no records, which costs a listing its detail
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* and costs nothing else.
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*
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* @param ctx The libdpm-core.so context
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*/
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void md_load_records_dir(dpm_ctx* ctx);
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/**
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* @brief Finds the records for a module name
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*
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* @param ctx The libdpm-core.so context
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* @param module_name The module name to look up
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* @return The records, or nullptr when no module of that name is recorded
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*/
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const dpm_module_meta_records* md_find_module_record(
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dpm_ctx* ctx, const std::string& module_name);
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/**
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* @brief Writes one module's records into the metadata directory
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*
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* Replaces the records of the same module name, and updates the
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* context's own copy so the change is visible without reopening.
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*
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* @param ctx The libdpm-core.so context
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* @param module_name The module name the records belong to
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* @param records The records to write
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* @param reason Receives the failure reason when the write fails
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* @return true on success
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*/
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bool md_write_module_record(dpm_ctx* ctx, const std::string& module_name,
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const dpm_module_meta_records& records,
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std::string& reason);
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/**
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* @brief Removes one module's records from the metadata directory
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*
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* @param ctx The libdpm-core.so context
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* @param module_name The module name whose records are removed
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* @param reason Receives the failure reason when the removal fails
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* @return true on success
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*/
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bool md_remove_module_record(dpm_ctx* ctx, const std::string& module_name,
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std::string& reason);
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} // namespace dpm_core
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