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Commit bb58b015 authored by Steve Muckle's avatar Steve Muckle
Browse files

libmodprobe: add support to remove modules 

Add a remove method which will unload a given module from the kernel,
along with any modules it depended on, assuming those modules are now
unused.

Change-Id: Ie66dc153ef1771f50e26421d38d3656e95954780
parent 73b2928b

libmodprobe/include/modprobe/modprobe.h

+2 −0
Original line number Diff line number Diff line
@@ -26,11 +26,13 @@ class Modprobe { 


    bool LoadListedModules();

    bool LoadWithAliases(const std::string& module_name, bool strict);

    bool Remove(const std::string& module_name);



  private:

    std::string MakeCanonical(const std::string& module_path);

    bool InsmodWithDeps(const std::string& module_name);

    bool Insmod(const std::string& path_name);

    bool Rmmod(const std::string& module_name);

    std::vector<std::string> GetDependencies(const std::string& module);

    bool ModuleExists(const std::string& module_name);

libmodprobe/libmodprobe.cpp

+15 −0
Original line number Diff line number Diff line
@@ -315,3 +315,18 @@ bool Modprobe::LoadListedModules() { 
    }

    return true;

}



bool Modprobe::Remove(const std::string& module_name) {

    auto dependencies = GetDependencies(MakeCanonical(module_name));

    if (dependencies.empty()) {

        LOG(ERROR) << "Empty dependencies for module " << module_name;

        return false;

    }

    if (!Rmmod(dependencies[0])) {

        return false;

    }

    for (auto dep = dependencies.begin() + 1; dep != dependencies.end(); ++dep) {

        Rmmod(*dep);

    }

    return true;

}

libmodprobe/libmodprobe_ext.cpp

+9 −0
Original line number Diff line number Diff line
@@ -51,6 +51,15 @@ bool Modprobe::Insmod(const std::string& path_name) { 
    return true;

}



bool Modprobe::Rmmod(const std::string& module_name) {

    int ret = syscall(__NR_delete_module, MakeCanonical(module_name).c_str(), O_NONBLOCK);

    if (ret != 0) {

        PLOG(ERROR) << "Failed to remove module '" << module_name << "'";

        return false;

    }

    return true;

}



bool Modprobe::ModuleExists(const std::string& module_name) {

    struct stat fileStat;

    auto deps = GetDependencies(module_name);

libmodprobe/libmodprobe_ext_test.cpp

+10 −0
Original line number Diff line number Diff line
@@ -51,6 +51,16 @@ bool Modprobe::Insmod(const std::string& path_name) { 
    return true;

}



bool Modprobe::Rmmod(const std::string& module_name) {

    for (auto it = modules_loaded.begin(); it != modules_loaded.end(); it++) {

        if (*it == module_name) {

            modules_loaded.erase(it);

            return true;

        }

    }

    return false;

}



bool Modprobe::ModuleExists(const std::string& module_name) {

    auto deps = GetDependencies(module_name);

    if (deps.empty()) {

libmodprobe/libmodprobe_test.cpp

+22 −0
Original line number Diff line number Diff line
@@ -56,6 +56,14 @@ TEST(libmodprobe, Test) { 
            "/test13.ko",

    };



    std::vector<std::string> expected_after_remove = {

            "/test14.ko", "/test15.ko",         "/test1.ko",

            "/test6.ko",  "/test2.ko",          "/test5.ko",

            "/test8.ko",  "/test7.ko param1=4", "/test9.ko param_x=1 param_y=2 param_z=3",

            "/test10.ko", "/test12.ko",         "/test11.ko",

            "/test13.ko",

    };



    const std::string modules_dep =

            "test1.ko:\n"

            "test2.ko:\n"
@@ -131,4 +139,18 @@ TEST(libmodprobe, Test) { 
    }



    EXPECT_TRUE(modules_loaded == expected_modules_loaded);



    EXPECT_TRUE(m.Remove("test4"));



    GTEST_LOG_(INFO) << "Expected modules loaded after removing test4 (in order):";

    for (auto i = expected_after_remove.begin(); i != expected_after_remove.end(); ++i) {

        *i = dir.path + *i;

        GTEST_LOG_(INFO) << "\"" << *i << "\"";

    }

    GTEST_LOG_(INFO) << "Actual modules loaded after removing test4 (in order):";

    for (auto i = modules_loaded.begin(); i != modules_loaded.end(); ++i) {

        GTEST_LOG_(INFO) << "\"" << *i << "\"";

    }



    EXPECT_TRUE(modules_loaded == expected_after_remove);

}