Remove 'grp' and merge into 'nss' and 'posix'

The majority of grp routines are entry points for nss functionality.
This commit removes the 'grp' subdirectory and moves all nss-relevant
functionality and all tests to 'nss', and the 'setgroups' stub into
'posix' (alongside the 'getgroups' stub).  References to grp/ are
accordingly changed.  In addition, compat-initgroups.c, a fallback
implementation of initgroups is renamed to initgroups-fallback.c so that
the build system does not confuse it for nss_compat/compat-initgroups.c.

Build time improves very slightly; e.g. down from an average of 45.5s to
44.5s on an 8-thread mobile x86_64 CPU.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/nss/putgrent.c b/nss/putgrent.c
new file mode 100644
index 0000000..93caea5
--- /dev/null
+++ b/nss/putgrent.c
@@ -0,0 +1,76 @@
+/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <nss.h>
+#include <stdio.h>
+#include <string.h>
+#include <grp.h>
+
+#define flockfile(s) _IO_flockfile (s)
+#define funlockfile(s) _IO_funlockfile (s)
+
+#define _S(x)	x ? x : ""
+
+/* Write an entry to the given stream.
+   This must know the format of the group file.  */
+int
+putgrent (const struct group *gr, FILE *stream)
+{
+  int retval;
+
+  if (__glibc_unlikely (gr == NULL) || __glibc_unlikely (stream == NULL)
+      || gr->gr_name == NULL || !__nss_valid_field (gr->gr_name)
+      || !__nss_valid_field (gr->gr_passwd)
+      || !__nss_valid_list_field (gr->gr_mem))
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  flockfile (stream);
+
+  if (gr->gr_name[0] == '+' || gr->gr_name[0] == '-')
+    retval = fprintf (stream, "%s:%s::",
+		      gr->gr_name, _S (gr->gr_passwd));
+  else
+    retval = fprintf (stream, "%s:%s:%lu:",
+		      gr->gr_name, _S (gr->gr_passwd),
+		      (unsigned long int) gr->gr_gid);
+  if (__builtin_expect (retval, 0) < 0)
+    {
+      funlockfile (stream);
+      return -1;
+    }
+
+  if (gr->gr_mem != NULL)
+    {
+      for (size_t i = 0; gr->gr_mem[i] != NULL; i++)
+	if (fprintf (stream, i == 0 ? "%s" : ",%s", gr->gr_mem[i]) < 0)
+	  {
+	    /* What else can we do?  */
+	    funlockfile (stream);
+	    return -1;
+	  }
+    }
+
+  retval = fputc_unlocked ('\n', stream);
+
+  funlockfile (stream);
+
+  return retval < 0 ? -1 : 0;
+}