diff --git a/ChangeLog b/ChangeLog
index 4a32be9..c803eff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,22 @@
+2024-12-20  Björn Esser  <besser82 at fedoraproject.org>
+
+	libnss_tcb: Match interfaces with NSS documention.
+	According to [1] the interfaces provided should be of return-type
+	'enum nss_status', and take 'int *errnop' as the fourth (and last)
+	parameter.  Additionally the returned status values should be
+	accompanied by a corresponding ERRNO value [2] passed by the errnop
+	pointer.
+	[1] https://www.gnu.org/software/libc/manual/html_node/NSS-Module-Function-Internals.html
+	[2] https://www.gnu.org/software/libc/manual/html_node/NSS-Modules-Interface.html
+	* libs/nss.c (_nss_tcb_setspent): Adapt return-type and use return
+	values from documented macro.
+	(_nss_tcb_endspent): Likewise.
+	(_nss_tcb_getspnam_r): Adapt return-type, change fourth parameter
+	to be 'int *errnop', use return values from documented macro, and
+	set proper errno in errnop before returning.  Also check the pointer
+	to result buffer, set by fgetspent_r(3), to be non-NULL.
+	(_nss_tcb_getspent_r): Likewise.
+
 2024-12-18  Björn Esser  <besser82 at fedoraproject.org>
 
 	libnss_tcb: Initialize or rewind dirstream from inside setspent(3).
diff --git a/libs/nss.c b/libs/nss.c
index 549957a..c0ee708 100644
--- a/libs/nss.c
+++ b/libs/nss.c
@@ -13,27 +13,27 @@
 
 static __thread DIR *tcbdir = NULL;
 
-int _nss_tcb_setspent(void)
+enum nss_status _nss_tcb_setspent(void)
 {
 	if (!tcbdir) {
 		tcbdir = opendir(TCB_DIR);
 		if (!tcbdir)
 			return NSS_STATUS_UNAVAIL;
 
-		return 1;
+		return NSS_STATUS_SUCCESS;
 	}
 
 	rewinddir(tcbdir);
-	return 1;
+	return NSS_STATUS_SUCCESS;
 }
 
-int _nss_tcb_endspent(void)
+enum nss_status _nss_tcb_endspent(void)
 {
 	if (tcbdir) {
 		closedir(tcbdir);
 		tcbdir = NULL;
 	}
-	return 1;
+	return NSS_STATUS_SUCCESS;
 }
 
 static FILE *tcb_safe_open(const char *file, const char *name)
@@ -66,51 +66,76 @@ static FILE *tcb_safe_open(const char *file, const char *name)
 	return f;
 }
 
-int _nss_tcb_getspnam_r(const char *name, struct spwd *__result_buf,
-    char *__buffer, size_t __buflen, struct spwd **__result)
+enum nss_status _nss_tcb_getspnam_r(const char *name,
+    struct spwd *__result_buf, char *__buffer, size_t __buflen, int *__errnop)
 {
 	FILE *f;
 	char *file;
 	int retval, saved_errno;
+	struct spwd **result_buf_ptr = NULL;
 
-	if (asprintf(&file, TCB_FMT, name) < 0)
+	if (asprintf(&file, TCB_FMT, name) < 0) {
+		*__errnop = EAGAIN;
 		return NSS_STATUS_TRYAGAIN;
+	}
+
 	f = tcb_safe_open(file, name);
 	free(file);
-	if (!f)
+	if (!f) {
+		*__errnop = ENOENT;
 		return NSS_STATUS_UNAVAIL;
+	}
 
-	retval = fgetspent_r(f, __result_buf, __buffer, __buflen, __result);
+	retval = fgetspent_r(f, __result_buf, __buffer,
+	    __buflen, result_buf_ptr);
 	saved_errno = errno;
 	fclose(f);
 	errno = saved_errno;
-	if (!retval)
+	if (!retval) {
+		if (!*result_buf_ptr) {
+			*__errnop = ENOENT;
+			return NSS_STATUS_NOTFOUND;
+		}
+
 		return NSS_STATUS_SUCCESS;
+	}
 
 	switch (saved_errno) {
 	case 0:
+		if (!*result_buf_ptr) {
+			*__errnop = ENOENT;
+			return NSS_STATUS_NOTFOUND;
+		}
+
 		return NSS_STATUS_SUCCESS;
 
 	case ENOENT:
+		*__errnop = ENOENT;
 		return NSS_STATUS_NOTFOUND;
 
+	case EAGAIN:
+		*__errnop = EAGAIN;
+		return NSS_STATUS_TRYAGAIN;
+
 	case ERANGE:
+		*__errnop = ERANGE;
 		return NSS_STATUS_TRYAGAIN;
 
 	default:
+		*__errnop = ENOENT;
 		return NSS_STATUS_UNAVAIL;
 	}
 }
 
-int _nss_tcb_getspent_r(struct spwd *__result_buf,
-    char *__buffer, size_t __buflen, struct spwd **__result)
+enum nss_status _nss_tcb_getspent_r(struct spwd *__result_buf,
+    char *__buffer, size_t __buflen, int *__errnop)
 {
 	struct dirent *result;
 	off_t currpos;
 	int retval, saved_errno;
 
 	if (!tcbdir) {
-		errno = ENOENT;
+		*__errnop = ENOENT;
 		return NSS_STATUS_UNAVAIL;
 	}
 
@@ -123,11 +148,13 @@ int _nss_tcb_getspent_r(struct spwd *__result_buf,
 			closedir(tcbdir);
 			errno = saved_errno;
 			tcbdir = NULL;
+			*__errnop = ENOENT;
 			return NSS_STATUS_UNAVAIL;
 		}
 		if (!result) {
 			closedir(tcbdir);
 			errno = ENOENT;
+			*__errnop = ENOENT;
 			tcbdir = NULL;
 			return NSS_STATUS_NOTFOUND;
 		}
@@ -136,7 +163,7 @@ int _nss_tcb_getspent_r(struct spwd *__result_buf,
 	    !strcmp(result->d_name, "..") || result->d_name[0] == ':');
 
 	retval = _nss_tcb_getspnam_r(result->d_name, __result_buf, __buffer,
-	    __buflen, __result);
+	    __buflen, __errnop);
 
 	switch (retval) {
 	case NSS_STATUS_SUCCESS: