Refactor genesis download/load/check functions (#17276)

* Refactor genesis ingest functions

* Consolidate genesis.bin/genesis.tar.bz2 references

genesis-utils/src/lib.rs

@@ -0,0 +1,75 @@
+use solana_download_utils::download_genesis_if_missing;
+use solana_runtime::hardened_unpack::unpack_genesis_archive;
+use solana_sdk::{
+    genesis_config::{GenesisConfig, DEFAULT_GENESIS_ARCHIVE},
+    hash::Hash,
+};
+use std::net::SocketAddr;
+
+fn check_genesis_hash(
+    genesis_config: &GenesisConfig,
+    expected_genesis_hash: Option<Hash>,
+) -> Result<(), String> {
+    let genesis_hash = genesis_config.hash();
+
+    if let Some(expected_genesis_hash) = expected_genesis_hash {
+        if expected_genesis_hash != genesis_hash {
+            return Err(format!(
+                "Genesis hash mismatch: expected {} but downloaded genesis hash is {}",
+                expected_genesis_hash, genesis_hash,
+            ));
+        }
+    }
+
+    Ok(())
+}
+
+fn load_local_genesis(
+    ledger_path: &std::path::Path,
+    expected_genesis_hash: Option<Hash>,
+) -> Result<GenesisConfig, String> {
+    let existing_genesis = GenesisConfig::load(&ledger_path)
+        .map_err(|err| format!("Failed to load genesis config: {}", err))?;
+    check_genesis_hash(&existing_genesis, expected_genesis_hash)?;
+
+    Ok(existing_genesis)
+}
+
+pub fn download_then_check_genesis_hash(
+    rpc_addr: &SocketAddr,
+    ledger_path: &std::path::Path,
+    expected_genesis_hash: Option<Hash>,
+    max_genesis_archive_unpacked_size: u64,
+    no_genesis_fetch: bool,
+    use_progress_bar: bool,
+) -> Result<GenesisConfig, String> {
+    if no_genesis_fetch {
+        let genesis_config = load_local_genesis(ledger_path, expected_genesis_hash)?;
+        return Ok(genesis_config);
+    }
+
+    let genesis_package = ledger_path.join(DEFAULT_GENESIS_ARCHIVE);
+    let genesis_config = if let Ok(tmp_genesis_package) =
+        download_genesis_if_missing(rpc_addr, &genesis_package, use_progress_bar)
+    {
+        unpack_genesis_archive(
+            &tmp_genesis_package,
+            &ledger_path,
+            max_genesis_archive_unpacked_size,
+        )
+        .map_err(|err| format!("Failed to unpack downloaded genesis config: {}", err))?;
+
+        let downloaded_genesis = GenesisConfig::load(&ledger_path)
+            .map_err(|err| format!("Failed to load downloaded genesis config: {}", err))?;
+
+        check_genesis_hash(&downloaded_genesis, expected_genesis_hash)?;
+        std::fs::rename(tmp_genesis_package, genesis_package)
+            .map_err(|err| format!("Unable to rename: {:?}", err))?;
+
+        downloaded_genesis
+    } else {
+        load_local_genesis(ledger_path, expected_genesis_hash)?
+    };
+
+    Ok(genesis_config)
+}