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, 65 insertions, 0 deletions

diff --git a/nss/fgetgrent_r.c b/nss/fgetgrent_r.c
new file mode 100644
index 0000000000..5ce70230f1
--- /dev/null
+++ b/nss/fgetgrent_r.c
@@ -0,0 +1,65 @@
+/* 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 <ctype.h>
+#include <errno.h>
+#include <grp.h>
+#include <stdio.h>
+
+/* Define a line parsing function using the common code
+   used in the nss_files module.  */
+
+#define STRUCTURE	group
+#define ENTNAME		grent
+struct grent_data {};
+
+#define TRAILING_LIST_MEMBER		gr_mem
+#define TRAILING_LIST_SEPARATOR_P(c)	((c) == ',')
+#include <nss/nss_files/files-parse.c>
+LINE_PARSER
+(,
+ STRING_FIELD (result->gr_name, ISCOLON, 0);
+ if (line[0] == '\0'
+     && (result->gr_name[0] == '+' || result->gr_name[0] == '-'))
+   {
+     result->gr_passwd = NULL;
+     result->gr_gid = 0;
+   }
+ else
+   {
+     STRING_FIELD (result->gr_passwd, ISCOLON, 0);
+     if (result->gr_name[0] == '+' || result->gr_name[0] == '-')
+       INT_FIELD_MAYBE_NULL (result->gr_gid, ISCOLON, 0, 10, , 0)
+     else
+       INT_FIELD (result->gr_gid, ISCOLON, 0, 10,)
+   }
+ )
+
+
+/* Read one entry from the given stream.  */
+int
+__fgetgrent_r (FILE *stream, struct group *resbuf, char *buffer, size_t buflen,
+	       struct group **result)
+{
+  int ret = __nss_fgetent_r (stream, resbuf, buffer, buflen, parse_line);
+  if (ret == 0)
+    *result = resbuf;
+  else
+    *result = NULL;
+  return ret;
+}
+weak_alias (__fgetgrent_r, fgetgrent_r)