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Commit d3dc3c82 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

fs_mgr: correct support for ro.build.system_root_image 

Failed to convert fstab entries from "/" to "/system" when setting
up directory tree.  Introduce an internal fs_mgr_mount_point to
simplify conversion.

Test: manual
Bug: 109821005
Change-Id: Iadc1e967b92702cf01b6522f8f13b2cf3685f2af
parent 53ba407a

fs_mgr/fs_mgr_overlayfs.cpp

+26 −34
Original line number Diff line number Diff line
@@ -141,14 +141,13 @@ constexpr char lowerdir_option[] = "lowerdir="; 
constexpr char upperdir_option[] = "upperdir=";



// default options for mount_point, returns empty string for none available.

std::string fs_mgr_get_overlayfs_options(const char* mount_point) {

    auto fsrec_mount_point = std::string(mount_point);

    auto candidate = fs_mgr_get_overlayfs_candidate(fsrec_mount_point);

std::string fs_mgr_get_overlayfs_options(const std::string& mount_point) {

    auto candidate = fs_mgr_get_overlayfs_candidate(mount_point);

    if (candidate.empty()) return "";



    auto context = fs_mgr_get_context(fsrec_mount_point);

    auto context = fs_mgr_get_context(mount_point);

    if (!context.empty()) context = ",rootcontext="s + context;

    return "override_creds=off,"s + lowerdir_option + fsrec_mount_point + "," + upperdir_option +

    return "override_creds=off,"s + lowerdir_option + mount_point + "," + upperdir_option +

           candidate + upper_name + ",workdir=" + candidate + work_name + context;

}
@@ -167,10 +166,11 @@ bool fs_mgr_system_root_image(const fstab* fstab) { 
    return true;

}



std::string fs_mgr_get_overlayfs_options(const fstab* fstab, const char* mount_point) {

    if (fs_mgr_system_root_image(fstab) && ("/"s == mount_point)) mount_point = "/system";



    return fs_mgr_get_overlayfs_options(mount_point);

const char* fs_mgr_mount_point(const fstab* fstab, const char* mount_point) {

    if (!mount_point) return mount_point;

    if ("/"s != mount_point) return mount_point;

    if (!fs_mgr_system_root_image(fstab)) return mount_point;

    return "/system";

}



// return true if system supports overlayfs
@@ -196,7 +196,7 @@ bool fs_mgr_wants_overlayfs(const fstab_rec* fsrec) { 
    if (!fsrec) return false;



    auto fsrec_mount_point = fsrec->mount_point;

    if (!fsrec_mount_point) return false;

    if (!fsrec_mount_point || !fsrec_mount_point[0]) return false;

    if (!fsrec->blk_device) return false;



    if (!fsrec->fs_type) return false;
@@ -309,15 +309,12 @@ bool fs_mgr_overlayfs_setup_one(const std::string& overlay, const std::string& m 
    return ret;

}



bool fs_mgr_overlayfs_mount(const fstab* fstab, const fstab_rec* fsrec) {

    if (!fs_mgr_wants_overlayfs(fsrec)) return false;

    auto fsrec_mount_point = fsrec->mount_point;

    if (!fsrec_mount_point || !fsrec_mount_point[0]) return false;

    auto options = fs_mgr_get_overlayfs_options(fstab, fsrec_mount_point);

bool fs_mgr_overlayfs_mount(const std::string& mount_point) {

    auto options = fs_mgr_get_overlayfs_options(mount_point);

    if (options.empty()) return false;



    // hijack __mount() report format to help triage

    auto report = "__mount(source=overlay,target="s + fsrec_mount_point + ",type=overlay";

    auto report = "__mount(source=overlay,target="s + mount_point + ",type=overlay";

    const auto opt_list = android::base::Split(options, ",");

    for (const auto opt : opt_list) {

        if (android::base::StartsWith(opt, upperdir_option)) {
@@ -327,7 +324,7 @@ bool fs_mgr_overlayfs_mount(const fstab* fstab, const fstab_rec* fsrec) { 
    }

    report = report + ")=";



    auto ret = mount("overlay", fsrec_mount_point, "overlay", MS_RDONLY | MS_RELATIME,

    auto ret = mount("overlay", mount_point.c_str(), "overlay", MS_RDONLY | MS_RELATIME,

                     options.c_str());

    if (ret) {

        PERROR << report << ret;
@@ -338,8 +335,7 @@ bool fs_mgr_overlayfs_mount(const fstab* fstab, const fstab_rec* fsrec) { 
    }

}



bool fs_mgr_overlayfs_already_mounted(const char* mount_point) {

    if (!mount_point) return false;

bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point) {

    std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(

            fs_mgr_read_fstab("/proc/mounts"), fs_mgr_free_fstab);

    if (!fstab) return false;
@@ -351,7 +347,7 @@ bool fs_mgr_overlayfs_already_mounted(const char* mount_point) { 
        if (("overlay"s != fs_type) && ("overlayfs"s != fs_type)) continue;

        auto fsrec_mount_point = fsrec->mount_point;

        if (!fsrec_mount_point) continue;

        if (strcmp(fsrec_mount_point, mount_point)) continue;

        if (mount_point != fsrec_mount_point) continue;

        const auto fs_options = fsrec->fs_options;

        if (!fs_options) continue;

        const auto options = android::base::Split(fs_options, ",");
@@ -377,11 +373,10 @@ bool fs_mgr_overlayfs_mount_all() { 


    for (auto i = 0; i < fstab->num_entries; i++) {

        const auto fsrec = &fstab->recs[i];

        auto fsrec_mount_point = fsrec->mount_point;

        if (!fsrec_mount_point) continue;

        if (fs_mgr_overlayfs_already_mounted(fsrec_mount_point)) continue;



        if (fs_mgr_overlayfs_mount(fstab.get(), fsrec)) ret = true;

        if (!fs_mgr_wants_overlayfs(fsrec)) continue;

        std::string mount_point(fs_mgr_mount_point(fstab.get(), fsrec->mount_point));

        if (fs_mgr_overlayfs_already_mounted(mount_point)) continue;

        if (fs_mgr_overlayfs_mount(mount_point)) ret = true;

    }

    return ret;

}
@@ -405,11 +400,12 @@ bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* 
    std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),

                                                                      fs_mgr_free_fstab);

    std::vector<std::string> mounts;

    mount_point = fs_mgr_mount_point(fstab.get(), mount_point);

    if (fstab) {

        if (!fs_mgr_get_entry_for_mount_point(fstab.get(), kOverlayMountPoint)) return ret;

        for (auto i = 0; i < fstab->num_entries; i++) {

            const auto fsrec = &fstab->recs[i];

            auto fsrec_mount_point = fsrec->mount_point;

            auto fsrec_mount_point = fs_mgr_mount_point(fstab.get(), fsrec->mount_point);

            if (!fsrec_mount_point) continue;

            if (mount_point && strcmp(fsrec_mount_point, mount_point)) continue;

            if (!fs_mgr_wants_overlayfs(fsrec)) continue;
@@ -418,9 +414,6 @@ bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* 
        if (mounts.empty()) return ret;

    }



    if (mount_point && ("/"s == mount_point) && fs_mgr_system_root_image(fstab.get())) {

        mount_point = "/system";

    }

    auto overlay = kOverlayMountPoint + "/overlay/";

    auto save_errno = errno;

    if (!mkdir(overlay.c_str(), 0755)) {
@@ -443,11 +436,10 @@ bool fs_mgr_overlayfs_setup(const char* backing, const char* mount_point, bool* 
// If something is altered, set *change.

bool fs_mgr_overlayfs_teardown(const char* mount_point, bool* change) {

    if (change) *change = false;

    if (mount_point && ("/"s == mount_point)) {

        std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)> fstab(

                fs_mgr_read_fstab_default(), fs_mgr_free_fstab);

        if (fs_mgr_system_root_image(fstab.get())) mount_point = "/system";

    }

    mount_point = fs_mgr_mount_point(std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)>(

                                             fs_mgr_read_fstab_default(), fs_mgr_free_fstab)

                                             .get(),

                                     mount_point);

    auto ret = true;

    const auto overlay = kOverlayMountPoint + "/overlay";

    const auto oldpath = overlay + (mount_point ?: "");