Handle EINTR error code returned from opendir and readdir.

Although not documented, this error code, reportedly, may be returned
on Apple operating systems and some BSD systems.

doc/release_history.html

@@ -45,6 +45,7 @@
   <li>Marked templated versions of <code>initial_path</code> as deprecated and removed from <b>v4</b>. Use the non-templated versions instead.</li>
   <li>Use <code>readdir</code> instead of <code>readdir_r</code> on more POSIX platforms, specifically on Mac OS and other Apple operating systems, FreeBSD, OpenBSD, DragonFly BSD, NetBSD, QNX 6.0 and later, Solaris 10 and later and Illumos-based systems. Solaris users with gcc are recommended to define <code>__SunOS_5_x</code> macros according to their target Solaris version (e.g. <code>__SunOS_5_11</code>) when building Boost. (<a href="https://github.com/boostorg/filesystem/issues/349">#349</a>)</li>
   <li>Support for platforms with non-thread-safe <code>readdir</code> is deprecated and will be removed in a future release. Although not required until <a href="https://pubs.opengroup.org/onlinepubs/9799919799/functions/readdir.html">POSIX.1-2024</a>, on modern systems <code>readdir</code> is thread-safe when used with separate <code>DIR</code> objects in different threads and on some systems <code>readdir_r</code> is marked as deprecated. POSIX.1-2024 has been updated accordingly and also marked <code>readdir_r</code> as obsolescent, with a planned removal in a future version of the specification.</li>
+  <li>On POSIX platforms, handle <code>EINTR</code> error code returned from <code>opendir</code>, <code>readdir</code> and equivalents. Although not documented, this error code, reportedly, may be returned on Apple operating systems and some BSD systems.</li>
 </ul>
 
 <h2>1.91.0</h2>

src/directory.cpp

@@ -417,11 +417,21 @@ inline int invoke_readdir(dir_itr_imp& imp, struct dirent** result)
 system::error_code dir_itr_increment(dir_itr_imp& imp, fs::path& filename, fs::file_status& sf, fs::file_status& symlink_sf)
 {
     dirent* result = nullptr;
-    int err = invoke_readdir(imp, &result);
-    if (BOOST_UNLIKELY(err != 0))
-        return system::error_code(err, system::system_category());
-    if (result == nullptr)
-        return dir_itr_close(imp);
+    while (true)
+    {
+        int err = invoke_readdir(imp, &result);
+        if (BOOST_UNLIKELY(err != 0))
+        {
+            if (err == EINTR)
+                continue;
+            return system::error_code(err, system::system_category());
+        }
+
+        if (result == nullptr)
+            return dir_itr_close(imp);
+
+        break;
+    }
 
     filename = result->d_name;
 
@@ -511,21 +521,35 @@ system::error_code dir_itr_create(boost::intrusive_ptr< detail::dir_itr_imp >& i
             return ec;
     }
 
-    pimpl->handle = ::fdopendir(fd.get());
-    if (BOOST_UNLIKELY(!pimpl->handle))
+    while (true)
     {
-        const int err = errno;
-        return system::error_code(err, system::system_category());
+        pimpl->handle = ::fdopendir(fd.get());
+        if (BOOST_UNLIKELY(!pimpl->handle))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+            return system::error_code(err, system::system_category());
+        }
+
+        break;
     }
 
     // At this point fd will be closed by closedir
     fd.release();
 #else // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
-    pimpl->handle = ::opendir(dir.c_str());
-    if (BOOST_UNLIKELY(!pimpl->handle))
+    while (true)
     {
-        const int err = errno;
-        return system::error_code(err, system::system_category());
+        pimpl->handle = ::opendir(dir.c_str());
+        if (BOOST_UNLIKELY(!pimpl->handle))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+            return system::error_code(err, system::system_category());
+        }
+
+        break;
     }
 #endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
 
@@ -1118,29 +1142,44 @@ bool is_empty_directory(boost::scope::unique_fd&& fd, path const& p, error_code*
             ::closedir(dir);
         }
     };
+    std::unique_ptr< DIR, closedir_deleter > dir;
 
     int err;
 
 #if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
-    std::unique_ptr< DIR, closedir_deleter > dir(::fdopendir(fd.get()));
-    if (BOOST_UNLIKELY(!dir))
+    while (true)
     {
-        err = errno;
-    fail:
-        emit_error(err, p, ec, "boost::filesystem::is_empty");
-        return false;
+        dir.reset(::fdopendir(fd.get()));
+        if (BOOST_UNLIKELY(!dir))
+        {
+            err = errno;
+            if (err == EINTR)
+                continue;
+        fail:
+            emit_error(err, p, ec, "boost::filesystem::is_empty");
+            return false;
+        }
+
+        break;
     }
 
     // At this point fd will be closed by closedir
     fd.release();
 #else // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
-    std::unique_ptr< DIR, closedir_deleter > dir(::opendir(p.c_str()));
-    if (BOOST_UNLIKELY(!dir))
+    while (true)
     {
-        err = errno;
-    fail:
-        emit_error(err, p, ec, "boost::filesystem::is_empty");
-        return false;
+        dir.reset(::opendir(p.c_str()));
+        if (BOOST_UNLIKELY(!dir))
+        {
+            err = errno;
+            if (err == EINTR)
+                continue;
+        fail:
+            emit_error(err, p, ec, "boost::filesystem::is_empty");
+            return false;
+        }
+
+        break;
     }
 #endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
 
@@ -1151,6 +1190,8 @@ bool is_empty_directory(boost::scope::unique_fd&& fd, path const& p, error_code*
         if (!ent)
         {
             err = errno;
+            if (err == EINTR)
+                continue;
             if (err != 0)
                 goto fail;