Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d838dde6 authored by Yi-Yo Chiang's avatar Yi-Yo Chiang
Browse files

fs_mgr: Refactor mandatory overlayfs kernel patch checks 

The check result can just return the exact mount flags to use, this
reduces code duplication at the caller's side.

Bug: 293695109
Test: adb-remount-test
Change-Id: I9b5c918968f2494c0c1be3cb8d8e6b527a9c4eb2
parent f6dc8ee3

fs_mgr/fs_mgr.cpp

+23 −22
Original line number Diff line number Diff line
@@ -2227,8 +2227,8 @@ bool fs_mgr_create_canonical_mount_point(const std::string& mount_point) { 
}



bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) {

    auto overlayfs_valid_result = fs_mgr_overlayfs_valid();

    if (overlayfs_valid_result == OverlayfsValidResult::kNotSupported) {

    const auto overlayfs_check_result = android::fs_mgr::CheckOverlayfs();

    if (!overlayfs_check_result.supported) {

        LERROR << __FUNCTION__ << "(): kernel does not support overlayfs";

        return false;

    }
@@ -2280,10 +2280,7 @@ bool fs_mgr_mount_overlayfs_fstab_entry(const FstabEntry& entry) { 
        }

    }



    auto options = "lowerdir=" + lowerdir;

    if (overlayfs_valid_result == OverlayfsValidResult::kOverrideCredsRequired) {

        options += ",override_creds=off";

    }

    const auto options = "lowerdir=" + lowerdir + overlayfs_check_result.mount_flags;



    // Use "overlay-" + entry.blk_device as the mount() source, so that adb-remout-test don't

    // confuse this with adb remount overlay, whose device name is "overlay".
@@ -2339,30 +2336,34 @@ std::string fs_mgr_get_context(const std::string& mount_point) { 
    return context;

}



OverlayfsValidResult fs_mgr_overlayfs_valid() {

    // Overlayfs available in the kernel, and patched for override_creds?

    if (access("/sys/module/overlay/parameters/override_creds", F_OK) == 0) {

        return OverlayfsValidResult::kOverrideCredsRequired;

    }

namespace android {

namespace fs_mgr {



OverlayfsCheckResult CheckOverlayfs() {

    if (!fs_mgr_filesystem_available("overlay")) {

        return OverlayfsValidResult::kNotSupported;

        return {.supported = false};

    }

    struct utsname uts;

    if (uname(&uts) == -1) {

        return OverlayfsValidResult::kNotSupported;

        return {.supported = false};

    }

    int major, minor;

    if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {

        return OverlayfsValidResult::kNotSupported;

        return {.supported = false};

    }

    if (major < 4) {

        return OverlayfsValidResult::kOk;

    // Overlayfs available in the kernel, and patched for override_creds?

    if (access("/sys/module/overlay/parameters/override_creds", F_OK) == 0) {

        auto mount_flags = ",override_creds=off"s;

        if (major > 5 || (major == 5 && minor >= 15)) {

            mount_flags += ",userxattr"s;

        }

    if (major > 4) {

        return OverlayfsValidResult::kNotSupported;

        return {.supported = true, .mount_flags = mount_flags};

    }

    if (minor > 3) {

        return OverlayfsValidResult::kNotSupported;

    if (major < 4 || (major == 4 && minor <= 3)) {

        return {.supported = true};

    }

    return OverlayfsValidResult::kOk;

    return {.supported = false};

}



}  // namespace fs_mgr

}  // namespace android

fs_mgr/fs_mgr_overlayfs_mount.cpp

+2 −20
Original line number Diff line number Diff line
@@ -23,7 +23,6 @@ 
#include <sys/stat.h>

#include <sys/statvfs.h>

#include <sys/types.h>

#include <sys/utsname.h>

#include <sys/vfs.h>

#include <unistd.h>
@@ -218,17 +217,6 @@ static std::string fs_mgr_get_overlayfs_candidate(const std::string& mount_point 
    return "";

}



static inline bool KernelSupportsUserXattrs() {

    struct utsname uts;

    uname(&uts);



    int major, minor;

    if (sscanf(uts.release, "%d.%d", &major, &minor) != 2) {

        return false;

    }

    return major > 5 || (major == 5 && minor >= 15);

}



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

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

    return "/system";
@@ -240,13 +228,7 @@ static std::string fs_mgr_get_overlayfs_options(const FstabEntry& entry) { 
    auto candidate = fs_mgr_get_overlayfs_candidate(mount_point);

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

    auto ret = kLowerdirOption + mount_point + "," + kUpperdirOption + candidate + kUpperName +

               ",workdir=" + candidate + kWorkName;

    if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {

        ret += ",override_creds=off";

    }

    if (KernelSupportsUserXattrs()) {

        ret += ",userxattr";

    }

               ",workdir=" + candidate + kWorkName + android::fs_mgr::CheckOverlayfs().mount_flags;

    for (const auto& flag : android::base::Split(entry.fs_options, ",")) {

        if (android::base::StartsWith(flag, "context=")) {

            ret += "," + flag;
@@ -608,7 +590,7 @@ bool OverlayfsSetupAllowed(bool verbose) { 
        return false;

    }

    // Check mandatory kernel patches.

    if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {

    if (!android::fs_mgr::CheckOverlayfs().supported) {

        if (verbose) {

            LOG(ERROR) << "Kernel does not support overlayfs";

        }

fs_mgr/fs_mgr_priv.h

+7 −7
Original line number Diff line number Diff line
@@ -100,18 +100,18 @@ bool fs_mgr_is_f2fs(const std::string& blk_device); 
bool fs_mgr_filesystem_available(const std::string& filesystem);

std::string fs_mgr_get_context(const std::string& mount_point);



enum class OverlayfsValidResult {

    kNotSupported = 0,

    kOk,

    kOverrideCredsRequired,

};

OverlayfsValidResult fs_mgr_overlayfs_valid();



namespace android {

namespace fs_mgr {



bool UnmapDevice(const std::string& name);

bool InRecovery();



struct OverlayfsCheckResult {

    bool supported;

    std::string mount_flags;

};



OverlayfsCheckResult CheckOverlayfs();



}  // namespace fs_mgr

}  // namespace android

fs_mgr/fs_mgr_vendor_overlay.cpp

+3 −5
Original line number Diff line number Diff line
@@ -85,10 +85,8 @@ bool fs_mgr_vendor_overlay_mount(const std::pair<std::string, std::string>& moun 
        return false;

    }



    auto options = kLowerdirOption + source_directory + ":" + vendor_mount_point;

    if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kOverrideCredsRequired) {

        options += ",override_creds=off";

    }

    const auto options = kLowerdirOption + source_directory + ":" + vendor_mount_point +

                         android::fs_mgr::CheckOverlayfs().mount_flags;

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

                  options + ")=";

    auto ret = mount("overlay", vendor_mount_point.c_str(), "overlay", MS_RDONLY | MS_NOATIME,
@@ -120,7 +118,7 @@ bool fs_mgr_vendor_overlay_mount_all() { 


    const auto vendor_overlay_dirs = fs_mgr_get_vendor_overlay_dirs(vndk_version);

    if (vendor_overlay_dirs.empty()) return true;

    if (fs_mgr_overlayfs_valid() == OverlayfsValidResult::kNotSupported) {

    if (!android::fs_mgr::CheckOverlayfs().supported) {

        LINFO << "vendor overlay: kernel does not support overlayfs";

        return false;

    }