[libc] Add 'struct ucred' definition. (#213152)

This is a Linux extension that allows to obtain credentials of a peer
process connected to a socket, e.g. via passing `SO_PEERCRED` to
`getsockopt` function.

GitOrigin-RevId: 7d5dd438b286d4812a8d2e753262cb6db1c3be51

include/CMakeLists.txt

diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 941c9c7..1c6c65f 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -858,6 +858,7 @@
     .llvm-libc-types.struct_msghdr
     .llvm-libc-types.struct_sockaddr
     .llvm-libc-types.struct_sockaddr_storage
+    .llvm-libc-types.struct_ucred
 )
 
 add_header_macro(

include/llvm-libc-types/CMakeLists.txt

diff --git a/include/llvm-libc-types/CMakeLists.txt b/include/llvm-libc-types/CMakeLists.txt
index 0854507..3286ebe 100644
--- a/include/llvm-libc-types/CMakeLists.txt
+++ b/include/llvm-libc-types/CMakeLists.txt
@@ -264,6 +264,7 @@
 add_header(struct_ifreq HDR struct_ifreq.h DEPENDS libc.include.llvm-libc-macros.net_if_macros .struct_sockaddr)
 add_header(struct_iovec HDR struct_iovec.h DEPENDS .size_t)
 add_header(struct_linger HDR struct_linger.h)
+add_header(struct_ucred HDR struct_ucred.h DEPENDS .pid_t .uid_t .gid_t)
 add_header(struct_cmsghdr HDR struct_cmsghdr.h DEPENDS .size_t)
 add_header(struct_msghdr HDR struct_msghdr.h DEPENDS .size_t .socklen_t .struct_iovec)
 add_header(struct_mmsghdr HDR struct_mmsghdr.h DEPENDS .struct_msghdr)

include/llvm-libc-types/struct_ucred.h

diff --git a/include/llvm-libc-types/struct_ucred.h b/include/llvm-libc-types/struct_ucred.h
new file mode 100644
index 0000000..727e18f
--- /dev/null
+++ b/include/llvm-libc-types/struct_ucred.h
@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Definition of struct ucred.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_STRUCT_UCRED_H
+#define LLVM_LIBC_TYPES_STRUCT_UCRED_H
+
+#include "gid_t.h"
+#include "pid_t.h"
+#include "uid_t.h"
+
+// Credentials of a peer process connected to a socket.
+struct ucred {
+  pid_t pid;
+  uid_t uid;
+  gid_t gid;
+};
+
+#endif // LLVM_LIBC_TYPES_STRUCT_UCRED_H

include/sys/socket.yaml

diff --git a/include/sys/socket.yaml b/include/sys/socket.yaml
index fb121fa..64a3a56 100644
--- a/include/sys/socket.yaml
+++ b/include/sys/socket.yaml
@@ -15,6 +15,9 @@
   - type_name: struct_msghdr
   - type_name: struct_iovec
   - type_name: struct_linger
+  - type_name: struct_ucred
+    standards:
+      - linux
   - type_name: size_t
   - type_name: ssize_t
 enums: []