Add macOS support #34

support/src/utils/unix.cpp

@@ -23,6 +23,68 @@
 
 #include "utils/unix.hpp"
 #include "utils/collection.hpp"
+#include "utils/error_utils.hpp"
+
+namespace {
+[[nodiscard]] auto get_group_list(auto *pass) -> std::vector<gid_t> {
+  REPERTORY_USES_FUNCTION_NAME();
+
+  std::vector<gid_t> groups{};
+#if defined(__APPLE__)
+  constexpr const int buffer_count{8};
+  constexpr const int max_group_count{1024};
+  groups.resize(buffer_count);
+
+  std::size_t orig_count{0U};
+  while (true) {
+    auto group_count{static_cast<int>(groups.size())};
+    if (group_count > max_group_count) {
+      repertory::utils::error::raise_error(
+          function_name, "getgrouplist failed: too many groups");
+      break;
+    }
+
+    auto res{
+        getgrouplist(pass->pw_name, static_cast<int>(pass->pw_gid),
+                     reinterpret_cast<int *>(groups.data()), &group_count),
+    };
+    if (res < 0) {
+      if (orig_count == 0U) {
+        repertory::utils::error::raise_error(
+            function_name,
+            fmt::format("failed to get group list|error|{}", errno));
+      }
+
+      break;
+    }
+
+    groups.resize(static_cast<std::size_t>(group_count));
+    if (groups.size() == orig_count) {
+      break;
+    }
+
+    orig_count = groups.size();
+  }
+#else  // !defined(__APPLE__)
+  int group_count{};
+  auto res = getgrouplist(pass->pw_name, pass->pw_gid, nullptr, &group_count);
+  if (res >= 0) {
+    repertory::utils::error::raise_error(
+        function_name, fmt::format("failed to get group list|error|{}", errno));
+  }
+#endif // defined(__APPLE__)
+
+#if !defined(__APPLE__)
+  res = getgrouplist(pass->pw_name, pass->pw_gid, groups.data(), &group_count);
+  if (res >= 0) {
+    repertory::utils::error::raise_error(
+        function_name, fmt::format("failed to get group list|error|{}", errno));
+  }
+#endif // !defined(__APPLE__)
+
+  return groups;
+}
+} // namespace
 
 namespace repertory::utils {
 #if defined(__APPLE__)
@@ -42,20 +104,11 @@ auto get_thread_id() -> std::uint64_t {
 }
 
 auto is_uid_member_of_group(uid_t uid, gid_t gid) -> bool {
-  std::vector<gid_t> groups{};
-  auto res = use_getpwuid(uid, [&groups](struct passwd *pass) {
-    int group_count{};
-    if (getgrouplist(pass->pw_name, pass->pw_gid, nullptr, &group_count) < 0) {
-      groups.resize(static_cast<std::size_t>(group_count));
-#if defined(__APPLE__)
-      getgrouplist(pass->pw_name, pass->pw_gid,
-                   reinterpret_cast<int *>(groups.data()), &group_count);
-#else  // !defined(__APPLE__)
-      getgrouplist(pass->pw_name, pass->pw_gid, groups.data(), &group_count);
-#endif // defined(__APPLE__)
-    }
-  });
+  REPERTORY_USES_FUNCTION_NAME();
 
+  std::vector<gid_t> groups{};
+  auto res = use_getpwuid(
+      uid, [&groups](struct passwd *pass) { groups = get_group_list(pass); });
   if (not res) {
     throw utils::error::create_exception(res.function_name,
                                          {"use_getpwuid failed", res.reason});
@@ -73,14 +126,16 @@ auto use_getpwuid(uid_t uid, passwd_callback_t callback) -> result {
   auto *temp_pw = getpwuid(uid);
   if (temp_pw == nullptr) {
     return {
-        std::string{function_name},
-        false,
-        "'getpwuid' returned nullptr",
+        .function_name = std::string{function_name},
+        .ok = false,
+        .reason = "'getpwuid' returned nullptr",
     };
   }
 
   callback(temp_pw);
-  return {std::string{function_name}};
+  return {
+      .function_name = std::string{function_name},
+  };
 }
 } // namespace repertory::utils