From 84272fde2e3851884efe2907ea1a5811beb86ca5 Mon Sep 17 00:00:00 2001
From: Siyuan Ren <netheril96@gmail.com>
Date: Sun, 28 Jul 2024 12:27:29 +0800
Subject: [PATCH] Allow owner override in full format

---
 sources/commands.cpp               | 33 +++++++++++++++++++++++++++++-
 sources/full_format.cpp            | 14 +++++++++++++
 sources/full_format.h              | 10 ++++++++-
 sources/fuse_high_level_ops_base.h |  7 +++++++
 test/test_full_format.cpp          |  1 +
 5 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/sources/commands.cpp b/sources/commands.cpp
index 0220812e..94e8edeb 100644
--- a/sources/commands.cpp
+++ b/sources/commands.cpp
@@ -595,7 +595,24 @@ class MountCommand : public CommandBase
                                       "When enabled, securefs does not encrypt or decrypt file "
                                       "names. Use it at your own risk. No effect on full format.",
                                       cmdline()};
-
+    TCLAP::ValueArg<int> uid_override{
+        "",
+        "uid-override",
+        "Forces every file to be owned by this uid in the virtual filesystem. If the value is -1, "
+        "then no override is in place",
+        false,
+        -1,
+        "int",
+        cmdline()};
+    TCLAP::ValueArg<int> gid_override{
+        "",
+        "gid-override",
+        "Forces every file to be owned by this gid in the virtual filesystem. If the value is -1, "
+        "then no override is in place",
+        false,
+        -1,
+        "int",
+        cmdline()};
     DecryptedSecurefsParams fsparams{};
 
 private:
@@ -718,6 +735,20 @@ class MountCommand : public CommandBase
                 [](const MountCommand& cmd) { return cmd.fsparams.size_params().iv_size(); })
             .registerProvider<fruit::Annotated<tBlockSize, unsigned>(const MountCommand&)>(
                 [](const MountCommand& cmd) { return cmd.fsparams.size_params().block_size(); })
+            .registerProvider<OwnerOverride(const MountCommand&)>(
+                [](const MountCommand& cmd)
+                {
+                    OwnerOverride result{};
+                    if (cmd.uid_override.getValue() != -1)
+                    {
+                        result.uid_override = cmd.uid_override.getValue();
+                    }
+                    if (cmd.gid_override.getValue() != -1)
+                    {
+                        result.gid_override = cmd.gid_override.getValue();
+                    }
+                    return result;
+                })
             .registerProvider<fruit::Annotated<tMasterKey, key_type>(const MountCommand&)>(
                 [](const MountCommand& cmd)
                 { return from_byte_string(cmd.fsparams.full_format_params().master_key()); })
diff --git a/sources/full_format.cpp b/sources/full_format.cpp
index 56f190c8..abb0cd9d 100644
--- a/sources/full_format.cpp
+++ b/sources/full_format.cpp
@@ -44,6 +44,7 @@ int FuseHighLevelOps::vgetattr(const char* path, fuse_stat* st, const fuse_conte
     }
     FileLockGuard lg(**opened);
     (**opened).stat(st);
+    postprocess_stat(st);
     return 0;
 };
 int FuseHighLevelOps::vfgetattr(const char* path,
@@ -54,6 +55,7 @@ int FuseHighLevelOps::vfgetattr(const char* path,
     auto fp = get_file(info);
     FileLockGuard lg(*fp);
     fp->stat(st);
+    postprocess_stat(st);
     return 0;
 };
 int FuseHighLevelOps::vopendir(const char* path, fuse_file_info* info, const fuse_context* ctx)
@@ -565,4 +567,16 @@ std::optional<FilePtrHolder> FuseHighLevelOps::open_all(absl::string_view path)
     return holder;
 }
 
+void FuseHighLevelOps::postprocess_stat(fuse_stat* st)
+{
+    if (owner_override_.uid_override.has_value())
+    {
+        st->st_uid = *owner_override_.uid_override;
+    }
+    if (owner_override_.gid_override.has_value())
+    {
+        st->st_gid = *owner_override_.gid_override;
+    }
+}
+
 }    // namespace securefs::full_format
diff --git a/sources/full_format.h b/sources/full_format.h
index 6d4b3f9e..3f3cf5c0 100644
--- a/sources/full_format.h
+++ b/sources/full_format.h
@@ -62,8 +62,13 @@ class FuseHighLevelOps : public ::securefs::FuseHighLevelOpsBase
     INJECT(FuseHighLevelOps(OSService& root,
                             FileTable& ft,
                             RepoLocker& locker,
+                            const OwnerOverride& owner_override,
                             ANNOTATED(tCaseInsensitive, bool) case_insensitive))
-        : root_(root), ft_(ft), locker_(locker), case_insensitive_(case_insensitive)
+        : root_(root)
+        , ft_(ft)
+        , locker_(locker)
+        , owner_override_(owner_override)
+        , case_insensitive_(case_insensitive)
     {
     }
 
@@ -144,6 +149,7 @@ class FuseHighLevelOps : public ::securefs::FuseHighLevelOpsBase
     OSService& root_;
     FileTable& ft_;
     [[maybe_unused]] RepoLocker& locker_;    // We only needs this to construct and destruct.
+    OwnerOverride owner_override_;
     bool case_insensitive_;
 
 private:
@@ -166,5 +172,7 @@ class FuseHighLevelOps : public ::securefs::FuseHighLevelOpsBase
     {
         info->fh = reinterpret_cast<uintptr_t>(fb);
     }
+
+    void postprocess_stat(fuse_stat* st);
 };
 }    // namespace securefs::full_format
diff --git a/sources/fuse_high_level_ops_base.h b/sources/fuse_high_level_ops_base.h
index 8b0f3458..c79ab588 100644
--- a/sources/fuse_high_level_ops_base.h
+++ b/sources/fuse_high_level_ops_base.h
@@ -3,8 +3,15 @@
 #include "object.h"
 #include "platform.h"    // IWYU pragma: keep
 
+#include <optional>
+
 namespace securefs
 {
+struct OwnerOverride
+{
+    std::optional<int> uid_override, gid_override;
+};
+
 class FuseHighLevelOpsBase : public Object
 {
 public:
diff --git a/test/test_full_format.cpp b/test/test_full_format.cpp
index 08190c78..d9f3099d 100644
--- a/test/test_full_format.cpp
+++ b/test/test_full_format.cpp
@@ -40,6 +40,7 @@ namespace
                     return CaseInsensitive ? Directory::DirNameComparison{&case_insensitive_compare}
                                            : Directory::DirNameComparison{&binary_compare};
                 })
+            .registerProvider([]() { return OwnerOverride{}; })
             .bindInstance(*os);
     }
     TEST_CASE("Full format test (case sensitive)")