collector: use non-throwing std::filesystem overloads

  Replaced throwing std::filesystem APIs with std::error_code overloads
  in fru_collector and sel_collector to prevent crashes.

  Tested:
  blaze test //third_party/milotic/external/cc/tlbmc/collector/...

  Google-Bug-Id: 478925741

PiperOrigin-RevId: 897503496
Change-Id: I33fcbb73979677724e1df42881bfad8fbc364a44

tlbmc/collector/fru_collector.cc

diff --git a/tlbmc/collector/fru_collector.cc b/tlbmc/collector/fru_collector.cc
index 3e3795d..7b79050 100644
--- a/tlbmc/collector/fru_collector.cc
+++ b/tlbmc/collector/fru_collector.cc
@@ -419,14 +419,20 @@
 void FruCollector::WriteCachedFru(const RawFruTable& fru_table,
                                   const std::string& cached_fru_table_path) {
   std::filesystem::path path(cached_fru_table_path);
-  std::error_code error_code;
   std::filesystem::path parent_path = path.parent_path();
-  if (!std::filesystem::exists(parent_path)) {
-    std::filesystem::create_directories(path.parent_path(), error_code);
-    if (error_code) {
+  std::error_code ec;
+  bool exists_result = std::filesystem::exists(parent_path, ec);
+  if (ec) {
+    LOG(ERROR) << "Error checking exists for path '" << parent_path
+               << "': " << ec.message();
+    return;
+  }
+  if (!exists_result) {
+    std::filesystem::create_directories(parent_path, ec);
+    if (ec) {
       LOG(WARNING) << "Error creating directories for cached FRU table file at "
                       "path: "
-                   << path.parent_path();
+                   << parent_path;
       return;
     }
   }

tlbmc/collector/sel_collector.cc

diff --git a/tlbmc/collector/sel_collector.cc b/tlbmc/collector/sel_collector.cc
index b7ee32b..59d756b 100644
--- a/tlbmc/collector/sel_collector.cc
+++ b/tlbmc/collector/sel_collector.cc
@@ -231,9 +231,23 @@
   bool found_any_sel_file = false;
   std::string last_file_path;
   std::error_code ec;
-  for (const std::filesystem::directory_entry& entry :
-       std::filesystem::directory_iterator(config_.sel_save_path(), ec)) {
-    if (!entry.is_regular_file()) {
+  auto it = std::filesystem::directory_iterator(config_.sel_save_path(), ec);
+  if (ec) {
+    return absl::InternalError(absl::StrCat(
+        "Failed to iterate over SEL save path: ", config_.sel_save_path()));
+  }
+  auto end = std::filesystem::directory_iterator();
+  for (; it != end; it.increment(ec)) {
+    const std::filesystem::directory_entry& entry = *it;
+
+    std::error_code reg_ec;
+    bool is_reg = entry.is_regular_file(reg_ec);
+    if (reg_ec) {
+      LOG(ERROR) << "Error checking is_regular_file for path '"
+                 << entry.path().string() << "': " << reg_ec.message();
+      continue;
+    }
+    if (!is_reg) {
       continue;
     }
     std::string file_name = entry.path().filename().string();