From f31641369fa75e7b420c1f925cdf16503e974c42 Mon Sep 17 00:00:00 2001
From: Gordon Ross <gordon.w.ross@gmail.com>
Date: Mon, 2 Mar 2026 00:01:14 -0500
Subject: [PATCH 1/2] Fix getdomainname for SunOS

---
 .../libs/System.Native/extra_libs.cmake       |  2 +-
 .../libs/System.Native/pal_networking.c       |  4 ++
 src/native/libs/configure.cmake               | 55 ++++++++++++-------
 3 files changed, 40 insertions(+), 21 deletions(-)

diff --git a/src/native/libs/System.Native/extra_libs.cmake b/src/native/libs/System.Native/extra_libs.cmake
index 68c2c128105b50..df3a6136c66fa5 100644
--- a/src/native/libs/System.Native/extra_libs.cmake
+++ b/src/native/libs/System.Native/extra_libs.cmake
@@ -7,7 +7,7 @@ macro(append_extra_system_libs NativeLibsExtra)
         find_library(INOTIFY_LIBRARY inotify HINTS ${CROSS_ROOTFS}/usr/local/lib)
         list(APPEND ${NativeLibsExtra} ${INOTIFY_LIBRARY})
     elseif (CLR_CMAKE_TARGET_SUNOS)
-        list(APPEND ${NativeLibsExtra} socket)
+        list(APPEND ${NativeLibsExtra} socket nsl)
     elseif (CLR_CMAKE_TARGET_HAIKU)
         list (APPEND ${NativeLibsExtra} network bsd)
     endif ()
diff --git a/src/native/libs/System.Native/pal_networking.c b/src/native/libs/System.Native/pal_networking.c
index 3b460d4c4e8296..1c2ad8643bca27 100644
--- a/src/native/libs/System.Native/pal_networking.c
+++ b/src/native/libs/System.Native/pal_networking.c
@@ -52,6 +52,10 @@
 #include <stdio.h>
 #endif
 #include <unistd.h>
+#if defined(TARGET_SUNOS) && HAVE_GETDOMAINNAME
+// SunOS has getdomainname in libnsl but no header declaration
+extern int getdomainname(char *name, int namelen);
+#endif
 #ifdef HAVE_PWD_H
 #include <pwd.h>
 #endif
diff --git a/src/native/libs/configure.cmake b/src/native/libs/configure.cmake
index 4da74e115c6db8..a8ea3ce052c22f 100644
--- a/src/native/libs/configure.cmake
+++ b/src/native/libs/configure.cmake
@@ -978,29 +978,44 @@ check_symbol_exists(
     unistd.h
     HAVE_GETPEEREID)
 
-check_symbol_exists(
-    getdomainname
-    unistd.h
-    HAVE_GETDOMAINNAME)
+set (PREVIOUS_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
+if (CLR_CMAKE_TARGET_SUNOS)
+    # On SunOS, getdomainname is in libnsl but not declared in any header
+    set(CMAKE_REQUIRED_LIBRARIES socket nsl)
+    check_function_exists(
+        getdomainname
+        HAVE_GETDOMAINNAME)
+else()
+    check_symbol_exists(
+        getdomainname
+        unistd.h
+        HAVE_GETDOMAINNAME)
+endif()
 
 # getdomainname on OSX takes an 'int' instead of a 'size_t'
 # check if compiling with 'size_t' would cause a warning
-set (PREVIOUS_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-set (CMAKE_REQUIRED_FLAGS "-Werror -Weverything")
-check_c_source_compiles(
-    "
-    #include <unistd.h>
-    int main(void)
-    {
-        size_t namelen = 20;
-        char name[20];
-        int dummy = getdomainname(name, namelen);
-        (void)dummy;
-        return 0;
-    }
-    "
-    HAVE_GETDOMAINNAME_SIZET)
-set (CMAKE_REQUIRED_FLAGS ${PREVIOUS_CMAKE_REQUIRED_FLAGS})
+if (CLR_CMAKE_TARGET_SUNOS)
+    # SunOS uses int, not size_t
+    set (HAVE_GETDOMAINNAME_SIZET 0)
+else()
+    set (PREVIOUS_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+    set (CMAKE_REQUIRED_FLAGS "-Werror -Weverything")
+    check_c_source_compiles(
+        "
+        #include <unistd.h>
+        int main(void)
+        {
+            size_t namelen = 20;
+            char name[20];
+            int dummy = getdomainname(name, namelen);
+            (void)dummy;
+            return 0;
+        }
+        "
+        HAVE_GETDOMAINNAME_SIZET)
+    set (CMAKE_REQUIRED_FLAGS ${PREVIOUS_CMAKE_REQUIRED_FLAGS})
+endif()
+set (CMAKE_REQUIRED_LIBRARIES ${PREVIOUS_CMAKE_REQUIRED_LIBRARIES})
 
 set (PREVIOUS_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
 if (HAVE_SYS_INOTIFY_H AND CLR_CMAKE_TARGET_FREEBSD)

From 715ecb5a42fbbc86d01e8ec900aa05a98459c3ff Mon Sep 17 00:00:00 2001
From: Radek Zikmund <32671551+rzikm@users.noreply.github.com>
Date: Mon, 16 Mar 2026 11:53:50 +0100
Subject: [PATCH 2/2] Apply code review suggestion

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 src/native/libs/configure.cmake | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/native/libs/configure.cmake b/src/native/libs/configure.cmake
index 03974f4c652b8f..726cad88f48d09 100644
--- a/src/native/libs/configure.cmake
+++ b/src/native/libs/configure.cmake
@@ -991,8 +991,8 @@ else()
         HAVE_GETDOMAINNAME)
 endif()
 
-# getdomainname on OSX takes an 'int' instead of a 'size_t'
-# check if compiling with 'size_t' would cause a warning
+# Some platforms (e.g. macOS, SunOS) define getdomainname with an 'int' length parameter
+# Check whether using 'size_t' for the length parameter would cause a warning
 if (CLR_CMAKE_TARGET_SUNOS)
     # SunOS uses int, not size_t
     set (HAVE_GETDOMAINNAME_SIZET 0)