Add helper to get errno and error message (#20324)

### Description
<!-- Describe your changes. -->
Add platform aware helper to fetch errno message string.


### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
For usage in #20077

---------

Co-authored-by: Edward Chen <[email protected]>

onnxruntime/core/platform/env.cc

@@ -34,4 +34,29 @@ std::ostream& operator<<(std::ostream& os, gsl::span<const LogicalProcessors> af
 
 Env::Env() = default;
 
+std::pair<int, std::string> GetErrnoInfo() {
+  auto err = errno;
+  std::string msg;
+
+  if (err != 0) {
+    char buf[512];
+
+#if defined(_WIN32)
+    auto ret = strerror_s(buf, sizeof(buf), err);
+    msg = ret == 0 ? buf : "Failed to get error message";  // buf is guaranteed to be null terminated by strerror_s
+#else
+    // strerror_r return type differs by platform.
+    auto ret = strerror_r(err, buf, sizeof(buf));
+    if constexpr (std::is_same_v<decltype(ret), int>) {  // POSIX returns int
+      msg = ret == 0 ? buf : "Failed to get error message";
+    } else {
+      // GNU returns char*
+      msg = ret;
+    }
+#endif
+  }
+
+  return {err, msg};
+}
+
 }  // namespace onnxruntime

onnxruntime/core/platform/env.h

@@ -96,6 +96,12 @@ struct ThreadOptions {
 std::ostream& operator<<(std::ostream& os, const LogicalProcessors&);
 std::ostream& operator<<(std::ostream& os, gsl::span<const LogicalProcessors>);
 
+/// <summary>
+/// Get errno and the corresponding error message.
+/// </summary>
+/// <returns>errno and the error message string if errno indicates an error.</returns>
+std::pair<int, std::string> GetErrnoInfo();
+
 /// \brief An interface used by the onnxruntime implementation to
 /// access operating system functionality like the filesystem etc.
 ///

onnxruntime/core/platform/posix/env.cc

@@ -62,39 +62,11 @@ class UnmapFileParam {
   size_t len;
 };
 
-/**
- * @brief Get System Error
- *
- * @return a pair of {errno, error message}
- */
-static std::pair<int, std::string> GetSystemError(int e) {
-  char buf[1024];
-  const char* msg = "";
-  if (e > 0) {
-#if defined(__GLIBC__) && defined(_GNU_SOURCE) && !defined(__ANDROID__)
-    msg = strerror_r(e, buf, sizeof(buf));
-#else
-    // for Mac OS X and Android lower than API 23
-    if (strerror_r(e, buf, sizeof(buf)) != 0) {
-      buf[0] = '\0';
-    }
-    msg = buf;
-#endif
-  }
-
-  return std::make_pair(e, msg);
-}
-
-static std::pair<int, std::string> GetSystemError() {
-  auto e = errno;
-  return GetSystemError(e);
-}
-
 static void UnmapFile(void* param) noexcept {
   std::unique_ptr<UnmapFileParam> p(reinterpret_cast<UnmapFileParam*>(param));
   int ret = munmap(p->addr, p->len);
   if (ret != 0) {
-    auto [err_no, err_msg] = GetSystemError();
+    auto [err_no, err_msg] = GetErrnoInfo();
     LOGS_DEFAULT(ERROR) << "munmap failed. error code: " << err_no << " error msg: " << err_msg;
   }
 }
@@ -104,8 +76,9 @@ struct FileDescriptorTraits {
   static Handle GetInvalidHandleValue() { return -1; }
   static void CleanUp(Handle h) {
     if (close(h) == -1) {
-      auto [err_no, err_msg] = GetSystemError();
-      LOGS_DEFAULT(ERROR) << "Failed to close file descriptor " << h << " - error code: " << err_no << " error msg: " << err_msg;
+      auto [err_no, err_msg] = GetErrnoInfo();
+      LOGS_DEFAULT(ERROR) << "Failed to close file descriptor " << h << " - error code: " << err_no
+                          << " error msg: " << err_msg;
     }
   }
 };
@@ -131,7 +104,7 @@ int nftw_remove(
     int /*typeflag*/, struct FTW* /*ftwbuf*/) {
   const auto result = remove(fpath);
   if (result != 0) {
-    auto [err_no, err_msg] = GetSystemError();
+    auto [err_no, err_msg] = GetErrnoInfo();
     LOGS_DEFAULT(WARNING) << "remove() failed. Error code: " << err_no << " error msg: " << err_msg
                           << ", path: " << fpath;
   }
@@ -188,22 +161,22 @@ class PosixThread : public EnvThread {
       pthread_attr_t attr;
       int s = pthread_attr_init(&attr);
       if (s != 0) {
-        auto [err_no, err_msg] = GetSystemError();
+        auto [err_no, err_msg] = GetErrnoInfo();
         ORT_THROW("pthread_attr_init failed, error code: ", err_no, " error msg: ", err_msg);
       }
 
       size_t stack_size = thread_options.stack_size;
       if (stack_size > 0) {
         s = pthread_attr_setstacksize(&attr, stack_size);
         if (s != 0) {
-          auto [err_no, err_msg] = GetSystemError();
+          auto [err_no, err_msg] = GetErrnoInfo();
           ORT_THROW("pthread_attr_setstacksize failed, error code: ", err_no, " error msg: ", err_msg);
         }
       }
 
       s = pthread_create(&hThread, &attr, ThreadMain, param_ptr.get());
       if (s != 0) {
-        auto [err_no, err_msg] = GetSystemError();
+        auto [err_no, err_msg] = GetErrnoInfo();
         ORT_THROW("pthread_create failed, error code: ", err_no, " error msg: ", err_msg);
       }
       param_ptr.release();
@@ -249,7 +222,8 @@ class PosixThread : public EnvThread {
                                 << ", index: " << p->index
                                 << ", mask: " << *p->affinity;
         } else {
-          auto [err_no, err_msg] = GetSystemError(ret);
+          errno = ret;
+          auto [err_no, err_msg] = GetErrnoInfo();
 #if !defined(USE_MIGRAPHX)
           LOGS_DEFAULT(ERROR) << "pthread_setaffinity_np failed for thread: " << syscall(SYS_gettid)
                               << ", index: " << p->index
@@ -461,7 +435,7 @@ class PosixEnv : public Env {
   }
 
   static common::Status ReportSystemError(const char* operation_name, const std::string& path) {
-    auto [err_no, err_msg] = GetSystemError();
+    auto [err_no, err_msg] = GetErrnoInfo();
     std::ostringstream oss;
     oss << operation_name << " file \"" << path << "\" failed: " << err_msg;
     return common::Status(common::SYSTEM, err_no, oss.str());

onnxruntime/core/platform/windows/env.cc

@@ -110,11 +110,10 @@ class WindowsThread : public EnvThread {
                                       local_param.get(), 0,
                                       &threadID);
       if (th_handle == 0) {
-        auto err = errno;
         auto dos_error = _doserrno;
-        char message_buf[256];
-        strerror_s(message_buf, sizeof(message_buf), err);
-        ORT_THROW("WindowThread:_beginthreadex failed with message: ", message_buf, " doserrno: ", dos_error);
+        auto [err, msg] = GetErrnoInfo();
+        ORT_THROW("WindowThread:_beginthreadex failed with errno:", err, " message:", msg,
+                  " doserrno:", dos_error);
       }
       local_param.release();
       hThread.reset(reinterpret_cast<HANDLE>(th_handle));

onnxruntime/test/platform/env_test.cc

@@ -33,5 +33,25 @@ TEST(PlatformEnvTest, DirectoryCreationAndDeletion) {
   ASSERT_FALSE(env.FolderExists(root_dir));
 }
 
+TEST(PlatformEnvTest, GetErrnoInfo) {
+  // command that should generate an errno error
+  std::ifstream file("non_existent_file");
+  ASSERT_TRUE(file.fail());
+  auto [err, msg] = GetErrnoInfo();
+  ASSERT_EQ(err, ENOENT);
+
+#if defined(_WIN32)
+#pragma warning(push)
+#pragma warning(disable : 4996)
+#endif
+
+  // GetErrnoInfo uses strerror_r or strerror_s depending on the platform. use the unsafe std::sterror to get the
+  // expected value given this is a unit test so doesn't have to be as robust.
+  ASSERT_EQ(msg, std::strerror(ENOENT));
+
+#if defined(_WIN32)
+#pragma warning(pop)
+#endif
+}
 }  // namespace test
 }  // namespace onnxruntime