handle files and directories locks

handle multiple locks acquired from the same process
improve logs
add tests
refactor use of LockFile
forbid locking twice same path from same PID
improve windows lockfile to match unix one
split Lock and LockFile
use byte 21 to set lock status
enable reading locked file on windows
ensure closing of file descriptor in Lock and LockFile destructors
add timeout implementation for unix
add testing lock cli for subprocess tests
add subprocess tests
add --lock-timeout to umamba
add clean lock files
add a clean lock files flag -l,--locks to umamba clean command
add cpp-filesystem pins to enforce correct version on dev mode

.github/workflows/main.yml

@@ -45,7 +45,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda install -n base python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cxx-compiler ccache cmake gtest gmock reproc-cpp yaml-cpp
+          conda install -n base python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cxx-compiler ccache cmake gtest gmock reproc-cpp yaml-cpp
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -147,7 +147,7 @@ jobs:
           export MAMBA_ROOT_PREFIX=~/mambaroot
           export MAMBA_EXE=$(pwd)/micromamba
           . $MAMBA_ROOT_PREFIX/etc/profile.d/mamba.sh
-          micromamba create -y -p ~/build_env pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cxx-compiler ccache cmake gtest gmock cpp-filesystem reproc-cpp yaml-cpp cli11 -c conda-forge
+          micromamba create -y -p ~/build_env pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cxx-compiler ccache cmake gtest gmock "cpp-filesystem>=1.5.8" reproc-cpp yaml-cpp cli11 -c conda-forge
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: build tests
@@ -169,6 +169,7 @@ jobs:
                    -DBUILD_BINDINGS=OFF \
                    -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
                    -DCMAKE_C_COMPILER_LAUNCHER=ccache
+          make test_mamba_lock -j2
           make test -j2
 
   umamba_tests:
@@ -208,7 +209,7 @@ jobs:
           export MAMBA_ROOT_PREFIX=~/mambaroot
           export MAMBA_EXE=$(pwd)/micromamba
           . $MAMBA_ROOT_PREFIX/etc/profile.d/mamba.sh
-          micromamba create -y -p ~/build_env pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cxx-compiler ccache cmake gtest gmock cpp-filesystem reproc-cpp yaml-cpp pyyaml cli11 -c conda-forge
+          micromamba create -y -p ~/build_env pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cxx-compiler ccache cmake gtest gmock "cpp-filesystem>=1.5.8" reproc-cpp yaml-cpp pyyaml cli11 -c conda-forge
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: build micromamba
@@ -323,7 +324,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda install -n base -q -y vs2017_win-64 ccache python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cmake gtest gmock ninja reproc-cpp yaml-cpp cli11
+          conda install -n base -q -y vs2017_win-64 ccache python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cmake gtest gmock ninja reproc-cpp yaml-cpp cli11
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -398,7 +399,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda create -q -y -n mamba-tests vs2017_win-64 ccache python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cmake gtest gmock ninja reproc-cpp yaml-cpp cli11 pytest
+          conda create -q -y -n mamba-tests vs2017_win-64 ccache python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cmake gtest gmock ninja reproc-cpp yaml-cpp cli11 pytest
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: Run C++ tests Windows
@@ -412,8 +413,8 @@ jobs:
                    -G "Ninja" ^
                    -DCMAKE_CXX_COMPILER_LAUNCHER=ccache ^
                    -DCMAKE_C_COMPILER_LAUNCHER=ccache
-
-          ninja test
+          ninja test_mamba_lock -j2
+          ninja test -j2
 
   umamba_tests_win:
     runs-on: ${{ matrix.os }}
@@ -508,7 +509,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
+          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: micromamba python based tests
@@ -549,7 +550,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
+          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: micromamba python based tests with pwsh
@@ -588,7 +589,7 @@ jobs:
         run: |
           conda config --add channels conda-forge
           conda config --set channel_priority strict
-          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json cpp-filesystem conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
+          conda create -q -y -n mamba-tests vs2017_win-64 python=$PYTHON_VERSION pip pybind11 libsolv libsodium libarchive "libcurl=7.76.1=*_0" nlohmann_json "cpp-filesystem>=1.5.8" conda cmake gtest gmock ninja reproc-cpp yaml-cpp pyyaml cli11 pytest pytest-lazy-fixture menuinst
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
       - name: micromamba python based tests

environment-dev.yml

@@ -15,7 +15,7 @@ dependencies:
   - cxx-compiler
   - gtest
   - gmock
-  - cpp-filesystem
+  - cpp-filesystem >=1.5.8
   - reproc-cpp
   - yaml-cpp
   - pyyaml

include/mamba/api/clean.hpp

@@ -14,6 +14,7 @@ namespace mamba
     const int MAMBA_CLEAN_INDEX = 1 << 1;
     const int MAMBA_CLEAN_PKGS = 1 << 2;
     const int MAMBA_CLEAN_TARBALLS = 1 << 3;
+    const int MAMBA_CLEAN_LOCKS = 1 << 4;
 
     void clean(int options);
 }

include/mamba/core/context.hpp

@@ -163,6 +163,8 @@ namespace mamba
         bool no_rc = false;
         bool no_env = false;
 
+        std::size_t lock_timeout = 0;
+
         // Conda compat
         bool add_pip_as_python_dependency = true;
 

include/mamba/core/util.hpp

@@ -7,6 +7,11 @@
 #ifndef MAMBA_CORE_UTIL_HPP
 #define MAMBA_CORE_UTIL_HPP
 
+#include "mamba/core/mamba_fs.hpp"
+#include "mamba/core/output.hpp"
+
+#include "nlohmann/json.hpp"
+
 #include <array>
 #include <iomanip>
 #include <limits>
@@ -18,11 +23,7 @@
 #include <time.h>
 #include <vector>
 #include <regex>
-
-#include "nlohmann/json.hpp"
-
-#include "mamba_fs.hpp"
-#include "output.hpp"
+#include <chrono>
 
 
 namespace mamba
@@ -132,28 +133,72 @@ namespace mamba
         fs::path m_path;
     };
 
+    class Lock;
+
     class LockFile
     {
     public:
-        LockFile(const fs::path& path);
+        // LockFile(const fs::path& path);
+        LockFile(const fs::path& path, const std::chrono::seconds& timeout);
         ~LockFile();
 
-        LockFile(const LockFile&) = delete;
-        LockFile& operator=(const LockFile&) = delete;
-        LockFile& operator=(LockFile&&) = default;
+        int fd() const;
 
-        fs::path& path();
-        operator fs::path();
+#ifdef _WIN32
+        // Using file descriptor on Windows may cause false negative
+        static bool is_locked(const fs::path& path);
+#else
+        // Opening a new file descriptor on Unix would clear locks
+        static bool is_locked(int fd);
+#endif
+        static int read_pid(int fd);
+
+    private:
+        fs::path m_path;
+        std::chrono::seconds m_timeout;
+        int m_fd = -1;
+
+        bool set_lock(bool blocking) const;
+
+        int read_pid() const;
+        bool write_pid(int pid) const;
+        bool locked() const;
+        bool lock(int pid, bool blocking) const;
+        bool unlock() const;
+        int close_fd();
+        void remove() noexcept;
+
+        friend class Lock;
+    };
+
+    class Lock
+    {
+    public:
+        Lock(const fs::path& path);
+        ~Lock();
+
+        Lock(const Lock&) = delete;
+        Lock& operator=(const Lock&) = delete;
+        Lock& operator=(Lock&&) = default;
+
+        bool locked() const;
+        int fd() const;
+        fs::path path() const;
 
     private:
         fs::path m_path;
-        int m_fd;
+        fs::path m_lock;
+        std::unique_ptr<LockFile> p_lock_file;
+        bool m_locked;
 
 #if defined(__APPLE__) or defined(__linux__)
         pid_t m_pid;
 #else
         int m_pid;
 #endif
+
+        bool try_lock();
+        bool lock();
     };
 
     /*************************

src/api/clean.cpp

@@ -8,6 +8,7 @@
 #include "mamba/api/configuration.hpp"
 
 #include "mamba/core/context.hpp"
+#include "mamba/core/mamba_fs.hpp"
 #include "mamba/core/package_cache.hpp"
 
 
@@ -25,21 +26,22 @@ namespace mamba
         bool clean_index = options & MAMBA_CLEAN_INDEX;
         bool clean_pkgs = options & MAMBA_CLEAN_PKGS;
         bool clean_tarballs = options & MAMBA_CLEAN_TARBALLS;
+        bool clean_locks = options & MAMBA_CLEAN_LOCKS;
 
-        if (!(clean_all || clean_index || clean_pkgs || clean_tarballs))
+        if (!(clean_all || clean_index || clean_pkgs || clean_tarballs || clean_locks))
         {
-            std::cout << "Nothing to do." << std::endl;
+            Console::stream() << "Nothing to do." << std::endl;
             return;
         }
 
-        Console::print("Collect information..");
+        Console::stream() << "Collect information..";
 
         std::vector<fs::path> envs;
 
         MultiPackageCache caches(ctx.pkgs_dirs);
         if (!ctx.dry_run && (clean_index || clean_all))
         {
-            Console::print("Cleaning index cache..");
+            Console::stream() << "Cleaning index cache..";
 
             for (auto* pkg_cache : caches.writable_caches())
                 if (fs::exists(pkg_cache->get_pkgs_dir() / "cache"))
@@ -55,6 +57,50 @@ namespace mamba
                 }
         }
 
+        if (!ctx.dry_run && (clean_locks || clean_all))
+        {
+            Console::stream() << "Cleaning lock files..";
+
+            for (auto* pkg_cache : caches.writable_caches())
+            {
+                if (fs::exists(pkg_cache->get_pkgs_dir()))
+                    for (auto& p : fs::directory_iterator(pkg_cache->get_pkgs_dir()))
+                    {
+                        if (p.exists() && ends_with(p.path().string(), ".lock")
+                            && fs::exists(rstrip(p.path().string(), ".lock")))
+                        {
+                            try
+                            {
+                                fs::remove(p);
+                            }
+                            catch (...)
+                            {
+                                LOG_WARNING << "Could not clean lock file '" << p.path().string()
+                                            << "'";
+                            }
+                        }
+                    }
+
+                if (fs::exists(pkg_cache->get_pkgs_dir() / "cache"))
+                    for (auto& p :
+                         fs::recursive_directory_iterator(pkg_cache->get_pkgs_dir() / "cache"))
+                    {
+                        if (p.exists() && ends_with(p.path().string(), ".lock"))
+                        {
+                            try
+                            {
+                                fs::remove(p);
+                            }
+                            catch (...)
+                            {
+                                LOG_WARNING << "Could not clean lock file '" << p.path().string()
+                                            << "'";
+                            }
+                        }
+                    }
+            }
+        }
+
         if (fs::exists(ctx.root_prefix / "conda-meta"))
         {
             envs.push_back(ctx.root_prefix);

src/api/configuration.cpp

@@ -814,6 +814,16 @@ namespace mamba
                         Spend extra time validating package contents. It consists of running
                         cryptographic verifications on channels and packages metadata.)")));
 
+        insert(Configurable("lock_timeout", &ctx.lock_timeout)
+                   .group("Link & Install")
+                   .set_rc_configurable()
+                   .set_env_var_names()
+                   .description("Lock timeout")
+                   .long_description(unindent(R"(
+                        Lock timeout for blocking mode when waiting for another process
+                        to release the path.
+                        Not configurable on Windows: set to 10s by WinAPI)")));
+
         // Output, Prompt and Flow
         insert(Configurable("always_yes", &ctx.always_yes)
                    .group("Output, Prompt and Flow Control")

src/api/install.cpp

@@ -339,10 +339,10 @@ namespace mamba
 
         std::vector<std::shared_ptr<MSubdirData>> subdirs;
         MultiDownloadTarget multi_dl;
-        std::unique_ptr<LockFile> subdir_download_lock;
+        std::unique_ptr<Lock> subdir_download_lock;
         if (!ctx.offline)
         {
-            subdir_download_lock = std::make_unique<LockFile>(cache_dir / "mamba.lock");
+            subdir_download_lock = std::make_unique<Lock>(cache_dir);
         }
 
         std::vector<std::pair<int, int>> priorities;
@@ -535,7 +535,7 @@ namespace mamba
                 detail::create_target_directory(ctx.target_prefix);
             }
             {
-                LockFile(pkgs_dirs / "mamba.lock");
+                Lock pkgs_dirs_lock(pkgs_dirs);
                 trans.execute(prefix_data);
             }
             for (auto other_spec : config.at("others_pkg_mgrs_specs")
@@ -774,7 +774,7 @@ namespace mamba
                 fs::create_directories(pkgs_dirs);
             }
 
-            LockFile(pkgs_dirs / "mamba.lock");
+            Lock pkgs_dirs_lock(pkgs_dirs);
 
             std::vector<std::unique_ptr<PackageDownloadExtractTarget>> targets;
             MultiDownloadTarget multi_dl;