utils.rs: remove duplicate tmpfiles entries

With Jonathan's suggestion:
from rpmostree_context_assemble(), we call a function like
`rpmostreecxx::deduplicate_tmpfiles_entries(tmprootfs_dfd)`, which scans
the dropins, sorts them into two `HashMaps` and then unlink all the
`pkg-*` files and create a single `pkg-rpm-ostree-autovar.conf`
(re-using the same prefix ensures that this same logic works client-side).
See #26 (comment)

Fixes #26

rpmostree-cxxrs.cxx

@@ -2921,6 +2921,9 @@ extern "C"
   void rpmostreecxx$cxxbridge1$cache_branch_to_nevra (::rust::Str nevra,
                                                       ::rust::String *return$) noexcept;
 
+  ::rust::repr::PtrLen
+  rpmostreecxx$cxxbridge1$deduplicate_tmpfiles_entries (::std::int32_t rootfs) noexcept;
+
   ::std::uint32_t
   rpmostreecxx$cxxbridge1$CxxGObjectArray$length (::rpmostreecxx::CxxGObjectArray &self) noexcept
   {
@@ -6055,6 +6058,16 @@ cache_branch_to_nevra (::rust::Str nevra) noexcept
   rpmostreecxx$cxxbridge1$cache_branch_to_nevra (nevra, &return$.value);
   return ::std::move (return$.value);
 }
+
+void
+deduplicate_tmpfiles_entries (::std::int32_t rootfs)
+{
+  ::rust::repr::PtrLen error$ = rpmostreecxx$cxxbridge1$deduplicate_tmpfiles_entries (rootfs);
+  if (error$.ptr)
+    {
+      throw ::rust::impl< ::rust::Error>::error (error$);
+    }
+}
 } // namespace rpmostreecxx
 
 extern "C"
@@ -6769,5 +6782,6 @@ Vec< ::rpmostreecxx::LockedPackage>::truncate (::std::size_t len)
 {
   return cxxbridge1$rust_vec$rpmostreecxx$LockedPackage$truncate (this, len);
 }
+
 } // namespace cxxbridge1
 } // namespace rust

rpmostree-cxxrs.h

@@ -2043,4 +2043,6 @@ ::rpmostreecxx::GKeyFile *treefile_to_origin (::rpmostreecxx::Treefile const &tf
 void origin_validate_roundtrip (::rpmostreecxx::GKeyFile const &kf) noexcept;
 
 ::rust::String cache_branch_to_nevra (::rust::Str nevra) noexcept;
+
+void deduplicate_tmpfiles_entries (::std::int32_t rootfs);
 } // namespace rpmostreecxx

rust/src/lib.rs

@@ -710,6 +710,7 @@ pub mod ffi {
     extern "Rust" {
         fn prepare_rpm_layering(rootfs: i32, merge_passwd_dir: &str) -> Result<bool>;
         fn complete_rpm_layering(rootfs: i32) -> Result<()>;
+        fn deduplicate_tmpfiles_entries(rootfs: i32) -> Result<()>;
         fn passwd_cleanup(rootfs: i32) -> Result<()>;
         fn migrate_group_except_root(rootfs: i32, preserved_groups: &Vec<String>) -> Result<()>;
         fn migrate_passwd_except_root(rootfs: i32) -> Result<()>;

rust/src/utils.rs

@@ -8,18 +8,23 @@
  */
 
 use crate::cxxrsutil::*;
+use crate::ffiutil;
 use crate::variant_utils;
 use anyhow::{bail, Context, Result};
 use camino::Utf8Path;
+use cap_std::fs::{Dir, OpenOptions};
 use cap_std::io_lifetimes::AsFilelike;
+use fn_error_context::context;
 use glib::Variant;
 use once_cell::sync::Lazy;
 use ostree_ext::prelude::*;
 use ostree_ext::{glib, ostree};
 use regex::Regex;
+use rustix::fs::OpenOptionsExt;
 use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
 use std::io::prelude::*;
+use std::io::BufReader;
 use std::os::fd::OwnedFd;
 use std::os::unix::io::IntoRawFd;
 use std::path::Path;
@@ -304,6 +309,104 @@ pub(crate) fn translate_path_for_ostree_impl(path: &str) -> Option<String> {
     None
 }
 
+#[context("Deduplicate tmpfiles entries")]
+pub fn deduplicate_tmpfiles_entries(tmprootfs_dfd: i32) -> CxxResult<()> {
+    let tmprootfs_dfd = unsafe { ffiutil::ffi_dirfd(tmprootfs_dfd)? };
+    static TMPFILESD: &str = "usr/lib/tmpfiles.d";
+    let tmpfiles_dir = tmprootfs_dfd
+        .open_dir(TMPFILESD)
+        .context("readdir {TMPFILESD}")?;
+
+    let mut auto_tmpfiles_list = Vec::new();
+    let mut system_tmpfiles_list = Vec::new();
+
+    for entry in tmpfiles_dir.entries()? {
+        let entry = entry?;
+        let name = entry.file_name();
+        let name = name.to_str().unwrap();
+        // skip README
+        if name == "README" {
+            continue;
+        }
+        if name.starts_with("pkg-") {
+            auto_tmpfiles_list.push(format!("{name}"));
+        } else {
+            system_tmpfiles_list.push(format!("{name}"));
+        }
+    }
+
+    if auto_tmpfiles_list.is_empty() || system_tmpfiles_list.is_empty() {
+        println!("Not found any auto-generated or system tmpfiles.d config");
+        return Ok(());
+    }
+
+    // save all entries to hashmaps
+    let mut auto_tmpfiles_entries =
+        save_tmpfile_entries(&tmpfiles_dir, &auto_tmpfiles_list).unwrap();
+    let system_tmpfiles_entries =
+        save_tmpfile_entries(&tmpfiles_dir, &system_tmpfiles_list).unwrap();
+
+    // remove duplicated entries in auto-generated tmpfiles.d,
+    // which are already in system
+    for key in system_tmpfiles_entries.keys() {
+        if auto_tmpfiles_entries.contains_key(key) {
+            auto_tmpfiles_entries.remove(key);
+        }
+    }
+
+    {
+        // save the noduplicated entries
+        let auto_tmpfiles_entries_nodup: Vec<String> =
+            auto_tmpfiles_entries.into_values().collect();
+
+        let mut openopts = OpenOptions::new();
+        openopts.create(true).write(true).mode(0o644);
+        static AUTOVAR_PATH: &str = "pkg-rpm-ostree-autovar.conf";
+        let mut path = tmpfiles_dir
+            .open_with(AUTOVAR_PATH, &openopts)
+            .with_context(|| format!("Creating {AUTOVAR_PATH}"))?;
+
+        for entry in auto_tmpfiles_entries_nodup {
+            path.write_all(entry.as_bytes())?;
+            path.write_all(b"\n")?;
+        }
+    }
+
+    // unlink all the auto-generated files
+    for path in &auto_tmpfiles_list {
+        tmpfiles_dir
+            .remove_file(path)
+            .with_context(|| format!("unlinkat({})", path))?;
+    }
+    Ok(())
+}
+
+#[context("Save tmpfiles entries to hashmap")]
+pub(crate) fn save_tmpfile_entries(
+    tmpfiles_dir: &Dir,
+    var_list: &Vec<String>,
+) -> Result<HashMap<String, String>> {
+    let mut tmpflies_entries: HashMap<String, String> = HashMap::new();
+    for tmpflies in var_list.iter() {
+        let contents = tmpfiles_dir.open(tmpflies).map(BufReader::new)?;
+
+        for (line_num, line) in contents.lines().enumerate() {
+            let input = line
+                .with_context(|| format!("failed to read tmpfiles entry at line {}", line_num))?;
+
+            // Skip empty and comment lines
+            if input.is_empty() || input.starts_with('#') {
+                continue;
+            }
+
+            let parts: Vec<&str> = input.split_whitespace().collect();
+            let entry = parts.get(1).unwrap();
+            tmpflies_entries.insert(entry.to_string(), input.to_string());
+        }
+    }
+    Ok(tmpflies_entries)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/libpriv/rpmostree-core.cxx

@@ -4442,6 +4442,11 @@ rpmostree_context_assemble (RpmOstreeContext *self, GCancellable *cancellable, G
         task->end (msg);
       }
 
+      /* Remove duplicated tmpfiles entries;
+       * see https://github.com/coreos/rpm-ostree/issues/26
+       */
+      ROSCXX_TRY (deduplicate_tmpfiles_entries (tmprootfs_dfd), error);
+
       /* We want this to be the first error message if something went wrong
        * with a script; see https://github.com/projectatomic/rpm-ostree/pull/888
        * (otherwise, on a script that did `rm -rf`, we'd fail first on the renameat below)