[libc-commits] [libc] [libc] Add getpwnam_r and getpwuid_r entrypoints (PR #220833)

[Alexey Samsonov via libc-commits]

================
@@ -64,5 +77,40 @@ ErrorOr<struct passwd *> read_next() {
   return &pwd_entry;
 }
 
+ErrorOr<struct passwd *> find_by_name(cpp::string_view name, struct passwd *pwd,
+                                      cpp::span<char> buffer,
+                                      const char *path) {
+  if (!pwd)
+    return Error(EINVAL);
+  pwd::ScopedFlatFileDatabase<struct passwd> local_db(path ? path
+                                                           : passwd_file_path);
+  auto matcher = [name](const struct passwd &entry) {
+    return cpp::string_view(entry.pw_name) == name;
+  };
+  auto res = local_db.lookup(matcher, pwd, buffer);
+  if (!res.has_value())
+    return Error(res.error());
+  if (!res.value())
+    return nullptr;
+  return pwd;
----------------
vonosmas wrote:

On success, we always return `pwd` (here and in similar function below), as `pwd` essentially acts as an output parameter. I wonder if we can have `find_by_name` and `find_by_uid` instead return ErrorOr<bool> find_by_name - and then we can just call `return local_db.lookup(matcher, pwd, buffer);` here, and call

```
auto res = passwd::find_by_name(name, pwd, cpp::span<char>(buffer, bufsize));
if (!res.has_value())
  return res.error();
*result = res.value() ? pwd : nullptr;
return 0;
```

in entrypoints?

https://github.com/llvm/llvm-project/pull/220833