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Commit 5eb441ca authored by Jooyung Han's avatar Jooyung Han
Browse files

Respect `namespace mnt` 

This fixes the regression of aosp/2153354.
SwitchToMountNamespaceIfNeeded() is supposed to switch between "default"
mount namespace and "bootstrap" mount namespace. But it shouldn't affect
services with its own mount namespace.

Bug: 239882455
Test: make a hal service start in a separate mount namespace
    using 'namespace mnt' in its definition.
    see the mount namespace of the service process
    $ cat /proc/$(pgrep -f myservice)/ns/mnt
Change-Id: I8c80eaec723241c405f48980b9e88640123c43ad
parent 6a058f49

init/mount_namespace.cpp

+20 −2
Original line number Diff line number Diff line
@@ -190,15 +190,33 @@ bool SetupMountNamespaces() { 
    return success;

}



// Switch the mount namespace of the current process from bootstrap to default OR from default to

// bootstrap. If the current mount namespace is neither bootstrap nor default, keep it that way.

Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace) {

    if (IsRecoveryMode() || !IsApexUpdatable()) {

        // we don't have multiple namespaces in recovery mode or if apex is not updatable

        return {};

    }

    const auto& ns_id = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_id : default_ns_id;



    const std::string current_namespace_id = GetMountNamespaceId();

    MountNamespace current_mount_namespace;

    if (current_namespace_id == bootstrap_ns_id) {

        current_mount_namespace = NS_BOOTSTRAP;

    } else if (current_namespace_id == default_ns_id) {

        current_mount_namespace = NS_DEFAULT;

    } else {

        // services with `namespace mnt` start in its own mount namespace. So we need to keep it.

        return {};

    }



    // We're already in the target mount namespace.

    if (current_mount_namespace == target_mount_namespace) {

        return {};

    }



    const auto& ns_fd = target_mount_namespace == NS_BOOTSTRAP ? bootstrap_ns_fd : default_ns_fd;

    const auto& ns_name = target_mount_namespace == NS_BOOTSTRAP ? "bootstrap" : "default";

    if (ns_id != GetMountNamespaceId() && ns_fd.get() != -1) {

    if (ns_fd.get() != -1) {

        if (setns(ns_fd.get(), CLONE_NEWNS) == -1) {

            return ErrnoError() << "Failed to switch to " << ns_name << " mount namespace.";

        }