Move nss_compat from nis to nss subdir and install it unconditionally

This has been tested that local lookup still works with and
without an installed libnss_nis, and that NIS lookup works when
libnss_nis is available.

8 files changed, 3339 insertions, 1 deletions

diff --git a/nss/Makefile b/nss/Makefile
index c9a5200..f27bed1 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -72,7 +72,7 @@ tests += tst-cancel-getpwuid_r
 endif
 
 # Specify rules for the nss_* modules.  We have some services.
-services		:= files db
+services		:= files db compat
 
 extra-libs		= $(services:%=libnss_%)
 # These libraries will be built in the `others' pass rather than
@@ -95,11 +95,15 @@ libnss_db-routines	:= $(libnss_db-dbs) db-open db-init hash-string
 generated		+= $(filter-out db-alias.c db-netgrp.c, \
 					$(addsuffix .c,$(libnss_db-dbs)))
 
+libnss_compat-routines	:= $(addprefix compat-,grp pwd spwd initgroups) \
+			   nisdomain
+
 install-others		+= $(inst_vardbdir)/Makefile
 
 # Build static module into libc if requested
 libnss_files-inhibit-o	= $(filter-out .os,$(object-suffixes))
 libnss_db-inhibit-o	= $(filter-out .os,$(object-suffixes))
+libnss_compat-inhibit-o	= $(filter-out .os,$(object-suffixes))
 ifeq ($(build-static-nss),yes)
 routines                += $(libnss_files-routines)
 static-only-routines    += $(libnss_files-routines)
diff --git a/nss/Versions b/nss/Versions
index 50268ed..7694998 100644
--- a/nss/Versions
+++ b/nss/Versions
@@ -162,3 +162,14 @@ libnss_db {
     _nss_db_init;
   }
 }
+
+libnss_compat {
+  GLIBC_PRIVATE {
+    _nss_compat_endgrent; _nss_compat_endpwent; _nss_compat_endspent;
+    _nss_compat_getgrent_r; _nss_compat_getgrgid_r; _nss_compat_getgrnam_r;
+    _nss_compat_getpwent_r; _nss_compat_getpwnam_r; _nss_compat_getpwuid_r;
+    _nss_compat_getspent_r; _nss_compat_getspnam_r;
+    _nss_compat_setgrent; _nss_compat_setpwent; _nss_compat_setspent;
+    _nss_compat_initgroups_dyn;
+  }
+}
diff --git a/nss/nss_compat/compat-grp.c b/nss/nss_compat/compat-grp.c
new file mode 100644
index 0000000..4d51fc9
--- /dev/null
+++ b/nss/nss_compat/compat-grp.c
@@ -0,0 +1,682 @@
+/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <nss.h>
+#include <nsswitch.h>
+#include <stdio_ext.h>
+#include <string.h>
+#include <libc-lock.h>
+#include <kernel-features.h>
+
+static service_user *ni;
+static enum nss_status (*nss_setgrent) (int stayopen);
+static enum nss_status (*nss_getgrnam_r) (const char *name,
+					  struct group * grp, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_getgrgid_r) (gid_t gid, struct group * grp,
+					  char *buffer, size_t buflen,
+					  int *errnop);
+static enum nss_status (*nss_getgrent_r) (struct group * grp, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_endgrent) (void);
+
+/* Get the declaration of the parser function.  */
+#define ENTNAME grent
+#define STRUCTURE group
+#define EXTERN_PARSER
+#include <nss/nss_files/files-parse.c>
+
+/* Structure for remembering -group members ... */
+#define BLACKLIST_INITIAL_SIZE 512
+#define BLACKLIST_INCREMENT 256
+struct blacklist_t
+{
+  char *data;
+  int current;
+  int size;
+};
+
+struct ent_t
+{
+  bool files;
+  enum nss_status setent_status;
+  FILE *stream;
+  struct blacklist_t blacklist;
+};
+typedef struct ent_t ent_t;
+
+static ent_t ext_ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
+
+/* Protect global state against multiple changers.  */
+__libc_lock_define_initialized (static, lock)
+
+/* Prototypes for local functions.  */
+static void blacklist_store_name (const char *, ent_t *);
+static bool in_blacklist (const char *, int, ent_t *);
+
+/* Initialize the NSS interface/functions. The calling function must
+   hold the lock.  */
+static void
+init_nss_interface (void)
+{
+  if (__nss_database_lookup ("group_compat", NULL, "nis", &ni) >= 0)
+    {
+      nss_setgrent = __nss_lookup_function (ni, "setgrent");
+      nss_getgrnam_r = __nss_lookup_function (ni, "getgrnam_r");
+      nss_getgrgid_r = __nss_lookup_function (ni, "getgrgid_r");
+      nss_getgrent_r = __nss_lookup_function (ni, "getgrent_r");
+      nss_endgrent = __nss_lookup_function (ni, "endgrent");
+    }
+}
+
+static enum nss_status
+internal_setgrent (ent_t *ent, int stayopen, int needent)
+{
+  enum nss_status status = NSS_STATUS_SUCCESS;
+
+  ent->files = true;
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  if (ent->stream == NULL)
+    {
+      ent->stream = fopen ("/etc/group", "rme");
+
+      if (ent->stream == NULL)
+	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+      else
+	/* We take care of locking ourself.  */
+	__fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
+    }
+  else
+    rewind (ent->stream);
+
+  if (needent && status == NSS_STATUS_SUCCESS && nss_setgrent)
+    ent->setent_status = nss_setgrent (stayopen);
+
+  return status;
+}
+
+
+enum nss_status
+_nss_compat_setgrent (int stayopen)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  result = internal_setgrent (&ext_ent, stayopen, 1);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static enum nss_status
+internal_endgrent (ent_t *ent)
+{
+  if (ent->stream != NULL)
+    {
+      fclose (ent->stream);
+      ent->stream = NULL;
+    }
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_endgrent (void)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (nss_endgrent)
+    nss_endgrent ();
+
+  result = internal_endgrent (&ext_ent);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+/* get the next group from NSS  (+ entry) */
+static enum nss_status
+getgrent_next_nss (struct group *result, ent_t *ent, char *buffer,
+		   size_t buflen, int *errnop)
+{
+  if (!nss_getgrent_r)
+    return NSS_STATUS_UNAVAIL;
+
+  /* If the setgrent call failed, say so.  */
+  if (ent->setent_status != NSS_STATUS_SUCCESS)
+    return ent->setent_status;
+
+  do
+    {
+      enum nss_status status;
+
+      if ((status = nss_getgrent_r (result, buffer, buflen, errnop)) !=
+	  NSS_STATUS_SUCCESS)
+	return status;
+    }
+  while (in_blacklist (result->gr_name, strlen (result->gr_name), ent));
+
+  return NSS_STATUS_SUCCESS;
+}
+
+/* This function handle the +group entrys in /etc/group */
+static enum nss_status
+getgrnam_plusgroup (const char *name, struct group *result, ent_t *ent,
+		    char *buffer, size_t buflen, int *errnop)
+{
+  if (!nss_getgrnam_r)
+    return NSS_STATUS_UNAVAIL;
+
+  enum nss_status status = nss_getgrnam_r (name, result, buffer, buflen,
+					   errnop);
+  if (status != NSS_STATUS_SUCCESS)
+    return status;
+
+  if (in_blacklist (result->gr_name, strlen (result->gr_name), ent))
+    return NSS_STATUS_NOTFOUND;
+
+  /* We found the entry.  */
+  return NSS_STATUS_SUCCESS;
+}
+
+static enum nss_status
+getgrent_next_file (struct group *result, ent_t *ent,
+		    char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  while (1)
+    {
+      fpos_t pos;
+      int parse_res = 0;
+      char *p;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines. */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
+	/* This is a real entry.  */
+	break;
+
+      /* -group */
+      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0'
+	  && result->gr_name[1] != '@')
+	{
+	  blacklist_store_name (&result->gr_name[1], ent);
+	  continue;
+	}
+
+      /* +group */
+      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
+	  && result->gr_name[1] != '@')
+	{
+	  size_t len = strlen (result->gr_name);
+	  char buf[len];
+	  enum nss_status status;
+
+	  /* Store the group in the blacklist for the "+" at the end of
+	     /etc/group */
+	  memcpy (buf, &result->gr_name[1], len);
+	  status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
+				       buffer, buflen, errnop);
+	  blacklist_store_name (buf, ent);
+	  if (status == NSS_STATUS_SUCCESS)	/* We found the entry. */
+	    break;
+	  else if (status == NSS_STATUS_RETURN /* We couldn't parse the entry*/
+		   || status == NSS_STATUS_NOTFOUND)	/* No group in NIS */
+	    continue;
+	  else
+	    {
+	      if (status == NSS_STATUS_TRYAGAIN)
+		/* The parser ran out of space.  */
+		goto erange_reset;
+
+	      return status;
+	    }
+	}
+
+      /* +:... */
+      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
+	{
+	  ent->files = false;
+
+	  return getgrent_next_nss (result, ent, buffer, buflen, errnop);
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+enum nss_status
+_nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen,
+			int *errnop)
+{
+  enum nss_status result = NSS_STATUS_SUCCESS;
+
+  __libc_lock_lock (lock);
+
+  /* Be prepared that the setgrent function was not called before.  */
+  if (ni == NULL)
+    init_nss_interface ();
+
+  if (ext_ent.stream == NULL)
+    result = internal_setgrent (&ext_ent, 1, 1);
+
+  if (result == NSS_STATUS_SUCCESS)
+    {
+      if (ext_ent.files)
+	result = getgrent_next_file (grp, &ext_ent, buffer, buflen, errnop);
+      else
+	result = getgrent_next_nss (grp, &ext_ent, buffer, buflen, errnop);
+    }
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+/* Searches in /etc/group and the NIS/NIS+ map for a special group */
+static enum nss_status
+internal_getgrnam_r (const char *name, struct group *result, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  while (1)
+    {
+      fpos_t pos;
+      int parse_res = 0;
+      char *p;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines. */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      /* This is a real entry.  */
+      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
+	{
+	  if (strcmp (result->gr_name, name) == 0)
+	    return NSS_STATUS_SUCCESS;
+	  else
+	    continue;
+	}
+
+      /* -group */
+      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
+	{
+	  if (strcmp (&result->gr_name[1], name) == 0)
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    continue;
+	}
+
+      /* +group */
+      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
+	{
+	  if (strcmp (name, &result->gr_name[1]) == 0)
+	    {
+	      enum nss_status status;
+
+	      status = getgrnam_plusgroup (name, result, ent,
+					   buffer, buflen, errnop);
+	      if (status == NSS_STATUS_RETURN)
+		/* We couldn't parse the entry */
+		continue;
+	      else
+		return status;
+	    }
+	}
+      /* +:... */
+      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
+	{
+	  enum nss_status status;
+
+	  status = getgrnam_plusgroup (name, result, ent,
+				       buffer, buflen, errnop);
+	  if (status == NSS_STATUS_RETURN)
+	    /* We couldn't parse the entry */
+	    continue;
+	  else
+	    return status;
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_getgrnam_r (const char *name, struct group *grp,
+			char *buffer, size_t buflen, int *errnop)
+{
+  ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
+  enum nss_status result;
+
+  if (name[0] == '-' || name[0] == '+')
+    return NSS_STATUS_NOTFOUND;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  __libc_lock_unlock (lock);
+
+  result = internal_setgrent (&ent, 0, 0);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop);
+
+  internal_endgrent (&ent);
+
+  return result;
+}
+
+/* Searches in /etc/group and the NIS/NIS+ map for a special group id */
+static enum nss_status
+internal_getgrgid_r (gid_t gid, struct group *result, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  while (1)
+    {
+      fpos_t pos;
+      int parse_res = 0;
+      char *p;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines. */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      /* This is a real entry.  */
+      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
+	{
+	  if (result->gr_gid == gid)
+	    return NSS_STATUS_SUCCESS;
+	  else
+	    continue;
+	}
+
+      /* -group */
+      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
+	{
+	  blacklist_store_name (&result->gr_name[1], ent);
+	  continue;
+	}
+
+      /* +group */
+      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
+	{
+	  /* Yes, no +1, see the memcpy call below.  */
+	  size_t len = strlen (result->gr_name);
+	  char buf[len];
+	  enum nss_status status;
+
+	  /* Store the group in the blacklist for the "+" at the end of
+	     /etc/group */
+	  memcpy (buf, &result->gr_name[1], len);
+	  status = getgrnam_plusgroup (&result->gr_name[1], result, ent,
+				       buffer, buflen, errnop);
+	  blacklist_store_name (buf, ent);
+	  if (status == NSS_STATUS_SUCCESS && result->gr_gid == gid)
+	    break;
+	  else
+	    continue;
+	}
+      /* +:... */
+      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
+	{
+	  if (!nss_getgrgid_r)
+	    return NSS_STATUS_UNAVAIL;
+
+	  enum nss_status status = nss_getgrgid_r (gid, result, buffer, buflen,
+						   errnop);
+	  if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_getgrgid_r (gid_t gid, struct group *grp,
+			char *buffer, size_t buflen, int *errnop)
+{
+  ent_t ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  __libc_lock_unlock (lock);
+
+  result = internal_setgrent (&ent, 0, 0);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop);
+
+  internal_endgrent (&ent);
+
+  return result;
+}
+
+
+/* Support routines for remembering -@netgroup and -user entries.
+   The names are stored in a single string with `|' as separator. */
+static void
+blacklist_store_name (const char *name, ent_t *ent)
+{
+  int namelen = strlen (name);
+  char *tmp;
+
+  /* first call, setup cache */
+  if (ent->blacklist.size == 0)
+    {
+      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
+      ent->blacklist.data = malloc (ent->blacklist.size);
+      if (ent->blacklist.data == NULL)
+	return;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+      ent->blacklist.current = 1;
+    }
+  else
+    {
+      if (in_blacklist (name, namelen, ent))
+	return;			/* no duplicates */
+
+      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
+	{
+	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
+	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
+	  if (tmp == NULL)
+	    {
+	      free (ent->blacklist.data);
+	      ent->blacklist.size = 0;
+	      return;
+	    }
+	  ent->blacklist.data = tmp;
+	}
+    }
+
+  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
+  *tmp++ = '|';
+  *tmp = '\0';
+  ent->blacklist.current += namelen + 1;
+
+  return;
+}
+
+/* Return whether ent->blacklist contains name.  */
+static bool
+in_blacklist (const char *name, int namelen, ent_t *ent)
+{
+  char buf[namelen + 3];
+  char *cp;
+
+  if (ent->blacklist.data == NULL)
+    return false;
+
+  buf[0] = '|';
+  cp = stpcpy (&buf[1], name);
+  *cp++ = '|';
+  *cp = '\0';
+  return strstr (ent->blacklist.data, buf) != NULL;
+}
diff --git a/nss/nss_compat/compat-initgroups.c b/nss/nss_compat/compat-initgroups.c
new file mode 100644
index 0000000..c1a9301
--- /dev/null
+++ b/nss/nss_compat/compat-initgroups.c
@@ -0,0 +1,575 @@
+/* Copyright (C) 1998-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <nss.h>
+#include <stdio_ext.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/param.h>
+#include <nsswitch.h>
+#include <libc-lock.h>
+#include <kernel-features.h>
+#include <scratch_buffer.h>
+
+static service_user *ni;
+/* Type of the lookup function.  */
+static enum nss_status (*nss_initgroups_dyn) (const char *, gid_t,
+					      long int *, long int *,
+					      gid_t **, long int, int *);
+static enum nss_status (*nss_getgrnam_r) (const char *name,
+					  struct group * grp, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_getgrgid_r) (gid_t gid, struct group * grp,
+					  char *buffer, size_t buflen,
+					  int *errnop);
+static enum nss_status (*nss_setgrent) (int stayopen);
+static enum nss_status (*nss_getgrent_r) (struct group * grp, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_endgrent) (void);
+
+/* Protect global state against multiple changers.  */
+__libc_lock_define_initialized (static, lock)
+
+
+/* Get the declaration of the parser function.  */
+#define ENTNAME grent
+#define STRUCTURE group
+#define EXTERN_PARSER
+#include <nss/nss_files/files-parse.c>
+
+/* Structure for remembering -group members ... */
+#define BLACKLIST_INITIAL_SIZE 512
+#define BLACKLIST_INCREMENT 256
+struct blacklist_t
+{
+  char *data;
+  int current;
+  int size;
+};
+
+struct ent_t
+{
+  bool files;
+  bool need_endgrent;
+  bool skip_initgroups_dyn;
+  FILE *stream;
+  struct blacklist_t blacklist;
+};
+typedef struct ent_t ent_t;
+
+/* Prototypes for local functions.  */
+static void blacklist_store_name (const char *, ent_t *);
+static bool in_blacklist (const char *, int, ent_t *);
+
+/* Initialize the NSS interface/functions. The calling function must
+   hold the lock.  */
+static void
+init_nss_interface (void)
+{
+  __libc_lock_lock (lock);
+
+  /* Retest.  */
+  if (ni == NULL
+      && __nss_database_lookup ("group_compat", NULL, "nis", &ni) >= 0)
+    {
+      nss_initgroups_dyn = __nss_lookup_function (ni, "initgroups_dyn");
+      nss_getgrnam_r = __nss_lookup_function (ni, "getgrnam_r");
+      nss_getgrgid_r = __nss_lookup_function (ni, "getgrgid_r");
+      nss_setgrent = __nss_lookup_function (ni, "setgrent");
+      nss_getgrent_r = __nss_lookup_function (ni, "getgrent_r");
+      nss_endgrent = __nss_lookup_function (ni, "endgrent");
+    }
+
+  __libc_lock_unlock (lock);
+}
+
+static enum nss_status
+internal_setgrent (ent_t *ent)
+{
+  enum nss_status status = NSS_STATUS_SUCCESS;
+
+  ent->files = true;
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  ent->stream = fopen ("/etc/group", "rme");
+
+  if (ent->stream == NULL)
+    status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+  else
+    /* We take care of locking ourself.  */
+    __fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
+
+  return status;
+}
+
+
+static enum nss_status
+internal_endgrent (ent_t *ent)
+{
+  if (ent->stream != NULL)
+    {
+      fclose (ent->stream);
+      ent->stream = NULL;
+    }
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  if (ent->need_endgrent && nss_endgrent != NULL)
+    nss_endgrent ();
+
+  return NSS_STATUS_SUCCESS;
+}
+
+/* Add new group record.  */
+static void
+add_group (long int *start, long int *size, gid_t **groupsp, long int limit,
+	   gid_t gid)
+{
+  gid_t *groups = *groupsp;
+
+  /* Matches user.  Insert this group.  */
+  if (__glibc_unlikely (*start == *size))
+    {
+      /* Need a bigger buffer.  */
+      gid_t *newgroups;
+      long int newsize;
+
+      if (limit > 0 && *size == limit)
+	/* We reached the maximum.  */
+	return;
+
+      if (limit <= 0)
+	newsize = 2 * *size;
+      else
+	newsize = MIN (limit, 2 * *size);
+
+      newgroups = realloc (groups, newsize * sizeof (*groups));
+      if (newgroups == NULL)
+	return;
+      *groupsp = groups = newgroups;
+      *size = newsize;
+    }
+
+  groups[*start] = gid;
+  *start += 1;
+}
+
+/* This function checks, if the user is a member of this group and if
+   yes, add the group id to the list.  Return nonzero is we couldn't
+   handle the group because the user is not in the member list.  */
+static int
+check_and_add_group (const char *user, gid_t group, long int *start,
+		     long int *size, gid_t **groupsp, long int limit,
+		     struct group *grp)
+{
+  char **member;
+
+  /* Don't add main group to list of groups.  */
+  if (grp->gr_gid == group)
+    return 0;
+
+  for (member = grp->gr_mem; *member != NULL; ++member)
+    if (strcmp (*member, user) == 0)
+      {
+	add_group (start, size, groupsp, limit, grp->gr_gid);
+	return 0;
+      }
+
+  return 1;
+}
+
+/* Get the next group from NSS  (+ entry). If the NSS module supports
+   initgroups_dyn, get all entries at once.  */
+static enum nss_status
+getgrent_next_nss (ent_t *ent, char *buffer, size_t buflen, const char *user,
+		   gid_t group, long int *start, long int *size,
+		   gid_t **groupsp, long int limit, int *errnop)
+{
+  enum nss_status status;
+  struct group grpbuf;
+
+  /* Try nss_initgroups_dyn if supported. We also need getgrgid_r.
+     If this function is not supported, step through the whole group
+     database with getgrent_r.  */
+  if (! ent->skip_initgroups_dyn)
+    {
+      long int mystart = 0;
+      long int mysize = limit <= 0 ? *size : limit;
+      gid_t *mygroups = malloc (mysize * sizeof (gid_t));
+
+      if (mygroups == NULL)
+	return NSS_STATUS_TRYAGAIN;
+
+      /* For every gid in the list we get from the NSS module,
+	 get the whole group entry. We need to do this, since we
+	 need the group name to check if it is in the blacklist.
+	 In worst case, this is as twice as slow as stepping with
+	 getgrent_r through the whole group database. But for large
+	 group databases this is faster, since the user can only be
+	 in a limited number of groups.  */
+      if (nss_initgroups_dyn (user, group, &mystart, &mysize, &mygroups,
+			      limit, errnop) == NSS_STATUS_SUCCESS)
+	{
+	  status = NSS_STATUS_NOTFOUND;
+
+	  /* If there is no blacklist we can trust the underlying
+	     initgroups implementation.  */
+	  if (ent->blacklist.current <= 1)
+	    for (int i = 0; i < mystart; i++)
+	      add_group (start, size, groupsp, limit, mygroups[i]);
+	  else
+	    {
+	      /* A temporary buffer. We use the normal buffer, until we find
+		 an entry, for which this buffer is to small.  In this case, we
+		 overwrite the pointer with one to a bigger buffer.  */
+	      char *tmpbuf = buffer;
+	      size_t tmplen = buflen;
+	      bool use_malloc = false;
+
+	      for (int i = 0; i < mystart; i++)
+		{
+		  while ((status = nss_getgrgid_r (mygroups[i], &grpbuf,
+						   tmpbuf, tmplen, errnop))
+			 == NSS_STATUS_TRYAGAIN
+			 && *errnop == ERANGE)
+                    {
+                      if (__libc_use_alloca (tmplen * 2))
+                        {
+                          if (tmpbuf == buffer)
+                            {
+                              tmplen *= 2;
+                              tmpbuf = __alloca (tmplen);
+                            }
+                          else
+                            tmpbuf = extend_alloca (tmpbuf, tmplen, tmplen * 2);
+                        }
+                      else
+                        {
+                          tmplen *= 2;
+                          char *newbuf = realloc (use_malloc ? tmpbuf : NULL, tmplen);
+
+                          if (newbuf == NULL)
+                            {
+                              status = NSS_STATUS_TRYAGAIN;
+			      goto done;
+                            }
+                          use_malloc = true;
+                          tmpbuf = newbuf;
+                        }
+                    }
+
+		  if (__builtin_expect  (status != NSS_STATUS_NOTFOUND, 1))
+		    {
+		      if (__builtin_expect  (status != NSS_STATUS_SUCCESS, 0))
+		        goto done;
+
+		      if (!in_blacklist (grpbuf.gr_name,
+					 strlen (grpbuf.gr_name), ent)
+			  && check_and_add_group (user, group, start, size,
+						  groupsp, limit, &grpbuf))
+			{
+			  if (nss_setgrent != NULL)
+			    {
+			      nss_setgrent (1);
+			      ent->need_endgrent = true;
+			    }
+			  ent->skip_initgroups_dyn = true;
+
+			  goto iter;
+			}
+		    }
+		}
+
+	      status = NSS_STATUS_NOTFOUND;
+
+ done:
+	      if (use_malloc)
+	        free (tmpbuf);
+	    }
+
+	  free (mygroups);
+
+	  return status;
+	}
+
+      free (mygroups);
+    }
+
+  /* If we come here, the NSS module does not support initgroups_dyn
+     or we were confronted with a split group.  In these cases we have
+     to step through the whole list ourself.  */
+ iter:
+  do
+    {
+      if ((status = nss_getgrent_r (&grpbuf, buffer, buflen, errnop)) !=
+	  NSS_STATUS_SUCCESS)
+	break;
+    }
+  while (in_blacklist (grpbuf.gr_name, strlen (grpbuf.gr_name), ent));
+
+  if (status == NSS_STATUS_SUCCESS)
+    check_and_add_group (user, group, start, size, groupsp, limit, &grpbuf);
+
+  return status;
+}
+
+static enum nss_status
+internal_getgrent_r (ent_t *ent, char *buffer, size_t buflen, const char *user,
+		     gid_t group, long int *start, long int *size,
+		     gid_t **groupsp, long int limit, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  struct group grpbuf;
+
+  if (!ent->files)
+    return getgrent_next_nss (ent, buffer, buflen, user, group,
+			      start, size, groupsp, limit, errnop);
+
+  while (1)
+    {
+      fpos_t pos;
+      int parse_res = 0;
+      char *p;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines. */
+	     /* Parse the line.  If it is invalid, loop to
+		get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_grent (p, &grpbuf, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      if (grpbuf.gr_name[0] != '+' && grpbuf.gr_name[0] != '-')
+	/* This is a real entry.  */
+	break;
+
+      /* -group */
+      if (grpbuf.gr_name[0] == '-' && grpbuf.gr_name[1] != '\0'
+	  && grpbuf.gr_name[1] != '@')
+	{
+	  blacklist_store_name (&grpbuf.gr_name[1], ent);
+	  continue;
+	}
+
+      /* +group */
+      if (grpbuf.gr_name[0] == '+' && grpbuf.gr_name[1] != '\0'
+	  && grpbuf.gr_name[1] != '@')
+	{
+	  if (in_blacklist (&grpbuf.gr_name[1],
+			    strlen (&grpbuf.gr_name[1]), ent))
+	    continue;
+	  /* Store the group in the blacklist for the "+" at the end of
+	     /etc/group */
+	  blacklist_store_name (&grpbuf.gr_name[1], ent);
+	  if (nss_getgrnam_r == NULL)
+	    return NSS_STATUS_UNAVAIL;
+	  else if (nss_getgrnam_r (&grpbuf.gr_name[1], &grpbuf, buffer,
+				   buflen, errnop) != NSS_STATUS_SUCCESS)
+	    continue;
+
+	  check_and_add_group (user, group, start, size, groupsp,
+			       limit, &grpbuf);
+
+	  return NSS_STATUS_SUCCESS;
+	}
+
+      /* +:... */
+      if (grpbuf.gr_name[0] == '+' && grpbuf.gr_name[1] == '\0')
+	{
+	  /* If the selected module does not support getgrent_r or
+	     initgroups_dyn, abort. We cannot find the needed group
+	     entries.  */
+	  if (nss_initgroups_dyn == NULL || nss_getgrgid_r == NULL)
+	    {
+	      if (nss_setgrent != NULL)
+		{
+		  nss_setgrent (1);
+		  ent->need_endgrent = true;
+		}
+	      ent->skip_initgroups_dyn = true;
+
+	      if (nss_getgrent_r == NULL)
+		return NSS_STATUS_UNAVAIL;
+	    }
+
+	  ent->files = false;
+
+	  return getgrent_next_nss (ent, buffer, buflen, user, group,
+				    start, size, groupsp, limit, errnop);
+	}
+    }
+
+  check_and_add_group (user, group, start, size, groupsp, limit, &grpbuf);
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+enum nss_status
+_nss_compat_initgroups_dyn (const char *user, gid_t group, long int *start,
+			    long int *size, gid_t **groupsp, long int limit,
+			    int *errnop)
+{
+  enum nss_status status;
+  ent_t intern = { true, false, false, NULL, {NULL, 0, 0} };
+
+  status = internal_setgrent (&intern);
+  if (status != NSS_STATUS_SUCCESS)
+    return status;
+
+  struct scratch_buffer tmpbuf;
+  scratch_buffer_init (&tmpbuf);
+
+  do
+    {
+      while ((status = internal_getgrent_r (&intern, tmpbuf.data, tmpbuf.length,
+					    user, group, start, size,
+					    groupsp, limit, errnop))
+	     == NSS_STATUS_TRYAGAIN && *errnop == ERANGE)
+        if (!scratch_buffer_grow (&tmpbuf))
+	    goto done;
+    }
+  while (status == NSS_STATUS_SUCCESS);
+
+  status = NSS_STATUS_SUCCESS;
+
+ done:
+  scratch_buffer_free (&tmpbuf);
+
+  internal_endgrent (&intern);
+
+  return status;
+}
+
+
+/* Support routines for remembering -@netgroup and -user entries.
+   The names are stored in a single string with `|' as separator. */
+static void
+blacklist_store_name (const char *name, ent_t *ent)
+{
+  int namelen = strlen (name);
+  char *tmp;
+
+  /* First call, setup cache.  */
+  if (ent->blacklist.size == 0)
+    {
+      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
+      ent->blacklist.data = malloc (ent->blacklist.size);
+      if (ent->blacklist.data == NULL)
+	return;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+      ent->blacklist.current = 1;
+    }
+  else
+    {
+      if (in_blacklist (name, namelen, ent))
+	return;			/* no duplicates */
+
+      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
+	{
+	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
+	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
+	  if (tmp == NULL)
+	    {
+	      free (ent->blacklist.data);
+	      ent->blacklist.size = 0;
+	      return;
+	    }
+	  ent->blacklist.data = tmp;
+	}
+    }
+
+  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
+  *tmp++ = '|';
+  *tmp = '\0';
+  ent->blacklist.current += namelen + 1;
+
+  return;
+}
+
+/* Return whether ent->blacklist contains name.  */
+static bool
+in_blacklist (const char *name, int namelen, ent_t *ent)
+{
+  char buf[namelen + 3];
+  char *cp;
+
+  if (ent->blacklist.data == NULL)
+    return false;
+
+  buf[0] = '|';
+  cp = stpcpy (&buf[1], name);
+  *cp++ = '|';
+  *cp = '\0';
+  return strstr (ent->blacklist.data, buf) != NULL;
+}
diff --git a/nss/nss_compat/compat-pwd.c b/nss/nss_compat/compat-pwd.c
new file mode 100644
index 0000000..b16eef5
--- /dev/null
+++ b/nss/nss_compat/compat-pwd.c
@@ -0,0 +1,1131 @@
+/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <nss.h>
+#include <nsswitch.h>
+#include <pwd.h>
+#include <stdio_ext.h>
+#include <string.h>
+#include <libc-lock.h>
+#include <kernel-features.h>
+
+#include "netgroup.h"
+#include "nisdomain.h"
+
+static service_user *ni;
+static enum nss_status (*nss_setpwent) (int stayopen);
+static enum nss_status (*nss_getpwnam_r) (const char *name,
+					  struct passwd * pwd, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_getpwuid_r) (uid_t uid, struct passwd * pwd,
+					  char *buffer, size_t buflen,
+					  int *errnop);
+static enum nss_status (*nss_getpwent_r) (struct passwd * pwd, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_endpwent) (void);
+
+/* Get the declaration of the parser function.  */
+#define ENTNAME pwent
+#define STRUCTURE passwd
+#define EXTERN_PARSER
+#include <nss/nss_files/files-parse.c>
+
+/* Structure for remembering -@netgroup and -user members ... */
+#define BLACKLIST_INITIAL_SIZE 512
+#define BLACKLIST_INCREMENT 256
+struct blacklist_t
+{
+  char *data;
+  int current;
+  int size;
+};
+
+struct ent_t
+{
+  bool netgroup;
+  bool first;
+  bool files;
+  enum nss_status setent_status;
+  FILE *stream;
+  struct blacklist_t blacklist;
+  struct passwd pwd;
+  struct __netgrent netgrdata;
+};
+typedef struct ent_t ent_t;
+
+static ent_t ext_ent = { false, false, true, NSS_STATUS_SUCCESS, NULL,
+			 { NULL, 0, 0 },
+			 { NULL, NULL, 0, 0, NULL, NULL, NULL }};
+
+/* Protect global state against multiple changers.  */
+__libc_lock_define_initialized (static, lock)
+
+/* Prototypes for local functions.  */
+static void blacklist_store_name (const char *, ent_t *);
+static bool in_blacklist (const char *, int, ent_t *);
+
+/* Initialize the NSS interface/functions. The calling function must
+   hold the lock.  */
+static void
+init_nss_interface (void)
+{
+  if (__nss_database_lookup ("passwd_compat", NULL, "nis", &ni) >= 0)
+    {
+      nss_setpwent = __nss_lookup_function (ni, "setpwent");
+      nss_getpwnam_r = __nss_lookup_function (ni, "getpwnam_r");
+      nss_getpwuid_r = __nss_lookup_function (ni, "getpwuid_r");
+      nss_getpwent_r = __nss_lookup_function (ni, "getpwent_r");
+      nss_endpwent = __nss_lookup_function (ni, "endpwent");
+    }
+}
+
+static void
+give_pwd_free (struct passwd *pwd)
+{
+  free (pwd->pw_name);
+  free (pwd->pw_passwd);
+  free (pwd->pw_gecos);
+  free (pwd->pw_dir);
+  free (pwd->pw_shell);
+
+  memset (pwd, '\0', sizeof (struct passwd));
+}
+
+static size_t
+pwd_need_buflen (struct passwd *pwd)
+{
+  size_t len = 0;
+
+  if (pwd->pw_passwd != NULL)
+    len += strlen (pwd->pw_passwd) + 1;
+
+  if (pwd->pw_gecos != NULL)
+    len += strlen (pwd->pw_gecos) + 1;
+
+  if (pwd->pw_dir != NULL)
+    len += strlen (pwd->pw_dir) + 1;
+
+  if (pwd->pw_shell != NULL)
+    len += strlen (pwd->pw_shell) + 1;
+
+  return len;
+}
+
+static void
+copy_pwd_changes (struct passwd *dest, struct passwd *src,
+		  char *buffer, size_t buflen)
+{
+  if (src->pw_passwd != NULL && strlen (src->pw_passwd))
+    {
+      if (buffer == NULL)
+	dest->pw_passwd = strdup (src->pw_passwd);
+      else if (dest->pw_passwd &&
+	       strlen (dest->pw_passwd) >= strlen (src->pw_passwd))
+	strcpy (dest->pw_passwd, src->pw_passwd);
+      else
+	{
+	  dest->pw_passwd = buffer;
+	  strcpy (dest->pw_passwd, src->pw_passwd);
+	  buffer += strlen (dest->pw_passwd) + 1;
+	  buflen = buflen - (strlen (dest->pw_passwd) + 1);
+	}
+    }
+
+  if (src->pw_gecos != NULL && strlen (src->pw_gecos))
+    {
+      if (buffer == NULL)
+	dest->pw_gecos = strdup (src->pw_gecos);
+      else if (dest->pw_gecos &&
+	       strlen (dest->pw_gecos) >= strlen (src->pw_gecos))
+	strcpy (dest->pw_gecos, src->pw_gecos);
+      else
+	{
+	  dest->pw_gecos = buffer;
+	  strcpy (dest->pw_gecos, src->pw_gecos);
+	  buffer += strlen (dest->pw_gecos) + 1;
+	  buflen = buflen - (strlen (dest->pw_gecos) + 1);
+	}
+    }
+  if (src->pw_dir != NULL && strlen (src->pw_dir))
+    {
+      if (buffer == NULL)
+	dest->pw_dir = strdup (src->pw_dir);
+      else if (dest->pw_dir && strlen (dest->pw_dir) >= strlen (src->pw_dir))
+	strcpy (dest->pw_dir, src->pw_dir);
+      else
+	{
+	  dest->pw_dir = buffer;
+	  strcpy (dest->pw_dir, src->pw_dir);
+	  buffer += strlen (dest->pw_dir) + 1;
+	  buflen = buflen - (strlen (dest->pw_dir) + 1);
+	}
+    }
+
+  if (src->pw_shell != NULL && strlen (src->pw_shell))
+    {
+      if (buffer == NULL)
+	dest->pw_shell = strdup (src->pw_shell);
+      else if (dest->pw_shell &&
+	       strlen (dest->pw_shell) >= strlen (src->pw_shell))
+	strcpy (dest->pw_shell, src->pw_shell);
+      else
+	{
+	  dest->pw_shell = buffer;
+	  strcpy (dest->pw_shell, src->pw_shell);
+	  buffer += strlen (dest->pw_shell) + 1;
+	  buflen = buflen - (strlen (dest->pw_shell) + 1);
+	}
+    }
+}
+
+static enum nss_status
+internal_setpwent (ent_t *ent, int stayopen, int needent)
+{
+  enum nss_status status = NSS_STATUS_SUCCESS;
+
+  ent->first = ent->netgroup = false;
+  ent->files = true;
+  ent->setent_status = NSS_STATUS_SUCCESS;
+
+  /* If something was left over free it.  */
+  if (ent->netgroup)
+    __internal_endnetgrent (&ent->netgrdata);
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  if (ent->stream == NULL)
+    {
+      ent->stream = fopen ("/etc/passwd", "rme");
+
+      if (ent->stream == NULL)
+	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+      else
+	/* We take care of locking ourself.  */
+	__fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
+    }
+  else
+    rewind (ent->stream);
+
+  give_pwd_free (&ent->pwd);
+
+  if (needent && status == NSS_STATUS_SUCCESS && nss_setpwent)
+    ent->setent_status = nss_setpwent (stayopen);
+
+  return status;
+}
+
+
+enum nss_status
+_nss_compat_setpwent (int stayopen)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  result = internal_setpwent (&ext_ent, stayopen, 1);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static enum nss_status
+internal_endpwent (ent_t *ent)
+{
+  if (ent->stream != NULL)
+    {
+      fclose (ent->stream);
+      ent->stream = NULL;
+    }
+
+  if (ent->netgroup)
+    __internal_endnetgrent (&ent->netgrdata);
+
+  ent->first = ent->netgroup = false;
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  give_pwd_free (&ent->pwd);
+
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_endpwent (void)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (nss_endpwent)
+    nss_endpwent ();
+
+  result = internal_endpwent (&ext_ent);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static enum nss_status
+getpwent_next_nss_netgr (const char *name, struct passwd *result, ent_t *ent,
+			 char *group, char *buffer, size_t buflen,
+			 int *errnop)
+{
+  char *curdomain = NULL, *host, *user, *domain, *p2;
+  int status;
+  size_t p2len;
+
+  /* Leave function if NSS module does not support getpwnam_r,
+     we need this function here.  */
+  if (!nss_getpwnam_r)
+    return NSS_STATUS_UNAVAIL;
+
+  if (ent->first)
+    {
+      memset (&ent->netgrdata, 0, sizeof (struct __netgrent));
+      __internal_setnetgrent (group, &ent->netgrdata);
+      ent->first = false;
+    }
+
+  while (1)
+    {
+      status = __internal_getnetgrent_r (&host, &user, &domain,
+					 &ent->netgrdata, buffer, buflen,
+					 errnop);
+      if (status != 1)
+	{
+	  __internal_endnetgrent (&ent->netgrdata);
+	  ent->netgroup = 0;
+	  give_pwd_free (&ent->pwd);
+	  return NSS_STATUS_RETURN;
+	}
+
+      if (user == NULL || user[0] == '-')
+	continue;
+
+      if (domain != NULL)
+	{
+	  if (curdomain == NULL
+	      && __nss_get_default_domain (&curdomain) != 0)
+	    {
+	      __internal_endnetgrent (&ent->netgrdata);
+	      ent->netgroup = false;
+	      give_pwd_free (&ent->pwd);
+	      return NSS_STATUS_UNAVAIL;
+	    }
+	  if (strcmp (curdomain, domain) != 0)
+	    continue;
+	}
+
+      /* If name != NULL, we are called from getpwnam.  */
+      if (name != NULL)
+	if (strcmp (user, name) != 0)
+	  continue;
+
+      p2len = pwd_need_buflen (&ent->pwd);
+      if (p2len > buflen)
+	{
+	  *errnop = ERANGE;
+	  return NSS_STATUS_TRYAGAIN;
+	}
+      p2 = buffer + (buflen - p2len);
+      buflen -= p2len;
+
+      if (nss_getpwnam_r (user, result, buffer, buflen, errnop) !=
+	  NSS_STATUS_SUCCESS)
+	continue;
+
+      if (!in_blacklist (result->pw_name, strlen (result->pw_name), ent))
+	{
+	  /* Store the User in the blacklist for possible the "+" at the
+	     end of /etc/passwd */
+	  blacklist_store_name (result->pw_name, ent);
+	  copy_pwd_changes (result, &ent->pwd, p2, p2len);
+	  break;
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+/* get the next user from NSS  (+ entry) */
+static enum nss_status
+getpwent_next_nss (struct passwd *result, ent_t *ent, char *buffer,
+		   size_t buflen, int *errnop)
+{
+  enum nss_status status;
+  char *p2;
+  size_t p2len;
+
+  /* Return if NSS module does not support getpwent_r.  */
+  if (!nss_getpwent_r)
+    return NSS_STATUS_UNAVAIL;
+
+  /* If the setpwent call failed, say so.  */
+  if (ent->setent_status != NSS_STATUS_SUCCESS)
+    return ent->setent_status;
+
+  p2len = pwd_need_buflen (&ent->pwd);
+  if (p2len > buflen)
+    {
+      *errnop = ERANGE;
+      return NSS_STATUS_TRYAGAIN;
+    }
+  p2 = buffer + (buflen - p2len);
+  buflen -= p2len;
+
+  if (ent->first)
+    ent->first = false;
+
+  do
+    {
+      if ((status = nss_getpwent_r (result, buffer, buflen, errnop)) !=
+	  NSS_STATUS_SUCCESS)
+	return status;
+    }
+  while (in_blacklist (result->pw_name, strlen (result->pw_name), ent));
+
+  copy_pwd_changes (result, &ent->pwd, p2, p2len);
+
+  return NSS_STATUS_SUCCESS;
+}
+
+/* This function handle the +user entrys in /etc/passwd */
+static enum nss_status
+getpwnam_plususer (const char *name, struct passwd *result, ent_t *ent,
+		   char *buffer, size_t buflen, int *errnop)
+{
+  if (!nss_getpwnam_r)
+    return NSS_STATUS_UNAVAIL;
+
+  struct passwd pwd;
+  memset (&pwd, '\0', sizeof (struct passwd));
+
+  copy_pwd_changes (&pwd, result, NULL, 0);
+
+  size_t plen = pwd_need_buflen (&pwd);
+  if (plen > buflen)
+    {
+      *errnop = ERANGE;
+      return NSS_STATUS_TRYAGAIN;
+    }
+  char *p = buffer + (buflen - plen);
+  buflen -= plen;
+
+  enum nss_status status = nss_getpwnam_r (name, result, buffer, buflen,
+					   errnop);
+  if (status != NSS_STATUS_SUCCESS)
+    return status;
+
+  if (in_blacklist (result->pw_name, strlen (result->pw_name), ent))
+    return NSS_STATUS_NOTFOUND;
+
+  copy_pwd_changes (result, &pwd, p, plen);
+  give_pwd_free (&pwd);
+  /* We found the entry.  */
+  return NSS_STATUS_SUCCESS;
+}
+
+static enum nss_status
+getpwent_next_file (struct passwd *result, ent_t *ent,
+		    char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  while (1)
+    {
+      fpos_t pos;
+      char *p;
+      int parse_res;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines.  */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_pwent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      if (result->pw_name[0] != '+' && result->pw_name[0] != '-')
+	/* This is a real entry.  */
+	break;
+
+      /* -@netgroup */
+      if (result->pw_name[0] == '-' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  /* XXX Do not use fixed length buffer.  */
+	  char buf2[1024];
+	  char *user, *host, *domain;
+	  struct __netgrent netgrdata;
+
+	  memset (&netgrdata, 0, sizeof (struct __netgrent));
+	  __internal_setnetgrent (&result->pw_name[2], &netgrdata);
+	  while (__internal_getnetgrent_r (&host, &user, &domain, &netgrdata,
+					   buf2, sizeof (buf2), errnop))
+	    {
+	      if (user != NULL && user[0] != '-')
+		blacklist_store_name (user, ent);
+	    }
+	  __internal_endnetgrent (&netgrdata);
+	  continue;
+	}
+
+      /* +@netgroup */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  enum nss_status status;
+
+	  ent->netgroup = true;
+	  ent->first = true;
+	  copy_pwd_changes (&ent->pwd, result, NULL, 0);
+
+	  status = getpwent_next_nss_netgr (NULL, result, ent,
+					    &result->pw_name[2],
+					    buffer, buflen, errnop);
+	  if (status == NSS_STATUS_RETURN)
+	    continue;
+	  else
+	    return status;
+	}
+
+      /* -user */
+      if (result->pw_name[0] == '-' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  blacklist_store_name (&result->pw_name[1], ent);
+	  continue;
+	}
+
+      /* +user */
+      if (result->pw_name[0] == '+' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  size_t len = strlen (result->pw_name);
+	  char buf[len];
+	  enum nss_status status;
+
+	  /* Store the User in the blacklist for the "+" at the end of
+	     /etc/passwd */
+	  memcpy (buf, &result->pw_name[1], len);
+	  status = getpwnam_plususer (&result->pw_name[1], result, ent,
+				      buffer, buflen, errnop);
+	  blacklist_store_name (buf, ent);
+
+	  if (status == NSS_STATUS_SUCCESS)	/* We found the entry. */
+	    break;
+	  else if (status == NSS_STATUS_RETURN	/* We couldn't parse the entry */
+		   || status == NSS_STATUS_NOTFOUND)	/* entry doesn't exist */
+	    continue;
+	  else
+	    {
+	      if (status == NSS_STATUS_TRYAGAIN)
+		{
+		  /* The parser ran out of space */
+		  fsetpos (ent->stream, &pos);
+		  *errnop = ERANGE;
+		}
+	      return status;
+	    }
+	}
+
+      /* +:... */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '\0')
+	{
+	  ent->files = false;
+	  ent->first = true;
+	  copy_pwd_changes (&ent->pwd, result, NULL, 0);
+
+	  return getpwent_next_nss (result, ent, buffer, buflen, errnop);
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+static enum nss_status
+internal_getpwent_r (struct passwd *pw, ent_t *ent, char *buffer,
+		     size_t buflen, int *errnop)
+{
+  if (ent->netgroup)
+    {
+      enum nss_status status;
+
+      /* We are searching members in a netgroup */
+      /* Since this is not the first call, we don't need the group name */
+      status = getpwent_next_nss_netgr (NULL, pw, ent, NULL, buffer, buflen,
+					errnop);
+      if (status == NSS_STATUS_RETURN)
+	return getpwent_next_file (pw, ent, buffer, buflen, errnop);
+      else
+	return status;
+    }
+  else if (ent->files)
+    return getpwent_next_file (pw, ent, buffer, buflen, errnop);
+  else
+    return getpwent_next_nss (pw, ent, buffer, buflen, errnop);
+
+}
+
+enum nss_status
+_nss_compat_getpwent_r (struct passwd *pwd, char *buffer, size_t buflen,
+			int *errnop)
+{
+  enum nss_status result = NSS_STATUS_SUCCESS;
+
+  __libc_lock_lock (lock);
+
+  /* Be prepared that the setpwent function was not called before.  */
+  if (ni == NULL)
+    init_nss_interface ();
+
+  if (ext_ent.stream == NULL)
+    result = internal_setpwent (&ext_ent, 1, 1);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getpwent_r (pwd, &ext_ent, buffer, buflen, errnop);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+/* Searches in /etc/passwd and the NIS/NIS+ map for a special user */
+static enum nss_status
+internal_getpwnam_r (const char *name, struct passwd *result, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+
+  while (1)
+    {
+      fpos_t pos;
+      char *p;
+      int parse_res;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    {
+	      return NSS_STATUS_NOTFOUND;
+	    }
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines.  */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_pwent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      /* This is a real entry.  */
+      if (result->pw_name[0] != '+' && result->pw_name[0] != '-')
+	{
+	  if (strcmp (result->pw_name, name) == 0)
+	    return NSS_STATUS_SUCCESS;
+	  else
+	    continue;
+	}
+
+      /* -@netgroup */
+      if (result->pw_name[0] == '-' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  if (innetgr (&result->pw_name[2], NULL, name, NULL))
+	    return NSS_STATUS_NOTFOUND;
+	  continue;
+	}
+
+      /* +@netgroup */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  enum nss_status status;
+
+	  if (innetgr (&result->pw_name[2], NULL, name, NULL))
+	    {
+	      status = getpwnam_plususer (name, result, ent, buffer,
+					  buflen, errnop);
+
+	      if (status == NSS_STATUS_RETURN)
+		continue;
+
+	      return status;
+	    }
+	  continue;
+	}
+
+      /* -user */
+      if (result->pw_name[0] == '-' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  if (strcmp (&result->pw_name[1], name) == 0)
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    continue;
+	}
+
+      /* +user */
+      if (result->pw_name[0] == '+' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  if (strcmp (name, &result->pw_name[1]) == 0)
+	    {
+	      enum nss_status status;
+
+	      status = getpwnam_plususer (name, result, ent, buffer, buflen,
+					  errnop);
+	      if (status == NSS_STATUS_RETURN)
+		/* We couldn't parse the entry */
+		return NSS_STATUS_NOTFOUND;
+	      else
+		return status;
+	    }
+	}
+
+      /* +:... */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '\0')
+	{
+	  enum nss_status status;
+
+	  status = getpwnam_plususer (name, result, ent,
+				      buffer, buflen, errnop);
+	  if (status == NSS_STATUS_SUCCESS)	/* We found the entry. */
+	    break;
+	  else if (status == NSS_STATUS_RETURN)	/* We couldn't parse the entry */
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+	}
+    }
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_getpwnam_r (const char *name, struct passwd *pwd,
+			char *buffer, size_t buflen, int *errnop)
+{
+  enum nss_status result;
+  ent_t ent = { false, false, true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 },
+		{ NULL, NULL, 0, 0, NULL, NULL, NULL }};
+
+  if (name[0] == '-' || name[0] == '+')
+    return NSS_STATUS_NOTFOUND;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  __libc_lock_unlock (lock);
+
+  result = internal_setpwent (&ent, 0, 0);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getpwnam_r (name, pwd, &ent, buffer, buflen, errnop);
+
+  internal_endpwent (&ent);
+
+  return result;
+}
+
+/* This function handle the + entry in /etc/passwd for getpwuid */
+static enum nss_status
+getpwuid_plususer (uid_t uid, struct passwd *result, char *buffer,
+		   size_t buflen, int *errnop)
+{
+  struct passwd pwd;
+  char *p;
+  size_t plen;
+
+  if (!nss_getpwuid_r)
+    return NSS_STATUS_UNAVAIL;
+
+  memset (&pwd, '\0', sizeof (struct passwd));
+
+  copy_pwd_changes (&pwd, result, NULL, 0);
+
+  plen = pwd_need_buflen (&pwd);
+  if (plen > buflen)
+    {
+      *errnop = ERANGE;
+      return NSS_STATUS_TRYAGAIN;
+    }
+  p = buffer + (buflen - plen);
+  buflen -= plen;
+
+  if (nss_getpwuid_r (uid, result, buffer, buflen, errnop) ==
+      NSS_STATUS_SUCCESS)
+    {
+      copy_pwd_changes (result, &pwd, p, plen);
+      give_pwd_free (&pwd);
+      /* We found the entry.  */
+      return NSS_STATUS_SUCCESS;
+    }
+  else
+    {
+      /* Give buffer the old len back */
+      buflen += plen;
+      give_pwd_free (&pwd);
+    }
+  return NSS_STATUS_RETURN;
+}
+
+/* Searches in /etc/passwd and the NSS subsystem for a special user id */
+static enum nss_status
+internal_getpwuid_r (uid_t uid, struct passwd *result, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+
+  while (1)
+    {
+      fpos_t pos;
+      char *p;
+      int parse_res;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines.  */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_pwent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      /* This is a real entry.  */
+      if (result->pw_name[0] != '+' && result->pw_name[0] != '-')
+	{
+	  if (result->pw_uid == uid)
+	    return NSS_STATUS_SUCCESS;
+	  else
+	    continue;
+	}
+
+      /* -@netgroup */
+      if (result->pw_name[0] == '-' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  /* -1, because we remove first two character of pw_name.  */
+	  size_t len = strlen (result->pw_name) - 1;
+	  char buf[len];
+	  enum nss_status status;
+
+	  memcpy (buf, &result->pw_name[2], len);
+
+	  status = getpwuid_plususer (uid, result, buffer, buflen, errnop);
+	  if (status == NSS_STATUS_SUCCESS &&
+	      innetgr (buf, NULL, result->pw_name, NULL))
+	    return NSS_STATUS_NOTFOUND;
+
+	  continue;
+	}
+
+      /* +@netgroup */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '@'
+	  && result->pw_name[2] != '\0')
+	{
+	  /* -1, because we remove first two characters of pw_name.  */
+	  size_t len = strlen (result->pw_name) - 1;
+	  char buf[len];
+	  enum nss_status status;
+
+	  memcpy (buf, &result->pw_name[2], len);
+
+	  status = getpwuid_plususer (uid, result, buffer, buflen, errnop);
+
+	  if (status == NSS_STATUS_RETURN)
+	    continue;
+
+	  if (status == NSS_STATUS_SUCCESS)
+	    {
+	      if (innetgr (buf, NULL, result->pw_name, NULL))
+		return NSS_STATUS_SUCCESS;
+	    }
+	  else if (status == NSS_STATUS_RETURN)	/* We couldn't parse the entry */
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+
+	  continue;
+	}
+
+      /* -user */
+      if (result->pw_name[0] == '-' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  size_t len = strlen (result->pw_name);
+	  char buf[len];
+	  enum nss_status status;
+
+	  memcpy (buf, &result->pw_name[1], len);
+
+	  status = getpwuid_plususer (uid, result, buffer, buflen, errnop);
+	  if (status == NSS_STATUS_SUCCESS &&
+	      innetgr (buf, NULL, result->pw_name, NULL))
+	    return NSS_STATUS_NOTFOUND;
+	  continue;
+	}
+
+      /* +user */
+      if (result->pw_name[0] == '+' && result->pw_name[1] != '\0'
+	  && result->pw_name[1] != '@')
+	{
+	  size_t len = strlen (result->pw_name);
+	  char buf[len];
+	  enum nss_status status;
+
+	  memcpy (buf, &result->pw_name[1], len);
+
+	  status = getpwuid_plususer (uid, result, buffer, buflen, errnop);
+
+	  if (status == NSS_STATUS_RETURN)
+	    continue;
+
+	  if (status == NSS_STATUS_SUCCESS)
+	    {
+	      if (strcmp (buf, result->pw_name) == 0)
+		return NSS_STATUS_SUCCESS;
+	    }
+	  else if (status == NSS_STATUS_RETURN)	/* We couldn't parse the entry */
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+
+	  continue;
+	}
+
+      /* +:... */
+      if (result->pw_name[0] == '+' && result->pw_name[1] == '\0')
+	{
+	  enum nss_status status;
+
+	  status = getpwuid_plususer (uid, result, buffer, buflen, errnop);
+	  if (status == NSS_STATUS_SUCCESS)	/* We found the entry. */
+	    break;
+	  else if (status == NSS_STATUS_RETURN)	/* We couldn't parse the entry */
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+	}
+    }
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_getpwuid_r (uid_t uid, struct passwd *pwd,
+			char *buffer, size_t buflen, int *errnop)
+{
+  enum nss_status result;
+  ent_t ent = { false, false, true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 },
+		{ NULL, NULL, 0, 0, NULL, NULL, NULL }};
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  __libc_lock_unlock (lock);
+
+  result = internal_setpwent (&ent, 0, 0);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getpwuid_r (uid, pwd, &ent, buffer, buflen, errnop);
+
+  internal_endpwent (&ent);
+
+  return result;
+}
+
+
+/* Support routines for remembering -@netgroup and -user entries.
+   The names are stored in a single string with `|' as separator. */
+static void
+blacklist_store_name (const char *name, ent_t *ent)
+{
+  int namelen = strlen (name);
+  char *tmp;
+
+  /* first call, setup cache */
+  if (ent->blacklist.size == 0)
+    {
+      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
+      ent->blacklist.data = malloc (ent->blacklist.size);
+      if (ent->blacklist.data == NULL)
+	return;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+      ent->blacklist.current = 1;
+    }
+  else
+    {
+      if (in_blacklist (name, namelen, ent))
+	return;			/* no duplicates */
+
+      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
+	{
+	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
+	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
+	  if (tmp == NULL)
+	    {
+	      free (ent->blacklist.data);
+	      ent->blacklist.size = 0;
+	      return;
+	    }
+	  ent->blacklist.data = tmp;
+	}
+    }
+
+  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
+  *tmp++ = '|';
+  *tmp = '\0';
+  ent->blacklist.current += namelen + 1;
+
+  return;
+}
+
+/* Returns whether ent->blacklist contains name.  */
+static bool
+in_blacklist (const char *name, int namelen, ent_t *ent)
+{
+  char buf[namelen + 3];
+  char *cp;
+
+  if (ent->blacklist.data == NULL)
+    return false;
+
+  buf[0] = '|';
+  cp = stpcpy (&buf[1], name);
+  *cp++ = '|';
+  *cp = '\0';
+  return strstr (ent->blacklist.data, buf) != NULL;
+}
diff --git a/nss/nss_compat/compat-spwd.c b/nss/nss_compat/compat-spwd.c
new file mode 100644
index 0000000..8a87547
--- /dev/null
+++ b/nss/nss_compat/compat-spwd.c
@@ -0,0 +1,857 @@
+/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <nss.h>
+#include <nsswitch.h>
+#include <shadow.h>
+#include <stdio_ext.h>
+#include <string.h>
+#include <libc-lock.h>
+#include <kernel-features.h>
+
+#include "netgroup.h"
+#include "nisdomain.h"
+
+static service_user *ni;
+static enum nss_status (*nss_setspent) (int stayopen);
+static enum nss_status (*nss_getspnam_r) (const char *name, struct spwd * sp,
+					  char *buffer, size_t buflen,
+					  int *errnop);
+static enum nss_status (*nss_getspent_r) (struct spwd * sp, char *buffer,
+					  size_t buflen, int *errnop);
+static enum nss_status (*nss_endspent) (void);
+
+/* Get the declaration of the parser function.  */
+#define ENTNAME spent
+#define STRUCTURE spwd
+#define EXTERN_PARSER
+#include <nss/nss_files/files-parse.c>
+
+/* Structure for remembering -@netgroup and -user members ... */
+#define BLACKLIST_INITIAL_SIZE 512
+#define BLACKLIST_INCREMENT 256
+struct blacklist_t
+{
+  char *data;
+  int current;
+  int size;
+};
+
+struct ent_t
+{
+  bool netgroup;
+  bool files;
+  bool first;
+  enum nss_status setent_status;
+  FILE *stream;
+  struct blacklist_t blacklist;
+  struct spwd pwd;
+  struct __netgrent netgrdata;
+};
+typedef struct ent_t ent_t;
+
+static ent_t ext_ent = { false, true, false, NSS_STATUS_SUCCESS, NULL,
+			 { NULL, 0, 0},
+			 { NULL, NULL, 0, 0, 0, 0, 0, 0, 0}};
+
+/* Protect global state against multiple changers.  */
+__libc_lock_define_initialized (static, lock)
+
+/* Prototypes for local functions.  */
+static void blacklist_store_name (const char *, ent_t *);
+static bool in_blacklist (const char *, int, ent_t *);
+
+/* Initialize the NSS interface/functions. The calling function must
+   hold the lock.  */
+static void
+init_nss_interface (void)
+{
+  if (__nss_database_lookup ("shadow_compat", "passwd_compat",
+			     "nis", &ni) >= 0)
+    {
+      nss_setspent = __nss_lookup_function (ni, "setspent");
+      nss_getspnam_r = __nss_lookup_function (ni, "getspnam_r");
+      nss_getspent_r = __nss_lookup_function (ni, "getspent_r");
+      nss_endspent = __nss_lookup_function (ni, "endspent");
+    }
+}
+
+static void
+give_spwd_free (struct spwd *pwd)
+{
+  free (pwd->sp_namp);
+  free (pwd->sp_pwdp);
+
+  memset (pwd, '\0', sizeof (struct spwd));
+  pwd->sp_warn = -1;
+  pwd->sp_inact = -1;
+  pwd->sp_expire = -1;
+  pwd->sp_flag = ~0ul;
+}
+
+static int
+spwd_need_buflen (struct spwd *pwd)
+{
+  int len = 0;
+
+  if (pwd->sp_pwdp != NULL)
+    len += strlen (pwd->sp_pwdp) + 1;
+
+  return len;
+}
+
+static void
+copy_spwd_changes (struct spwd *dest, struct spwd *src,
+		   char *buffer, size_t buflen)
+{
+  if (src->sp_pwdp != NULL && strlen (src->sp_pwdp))
+    {
+      if (buffer == NULL)
+	dest->sp_pwdp = strdup (src->sp_pwdp);
+      else if (dest->sp_pwdp &&
+	       strlen (dest->sp_pwdp) >= strlen (src->sp_pwdp))
+	strcpy (dest->sp_pwdp, src->sp_pwdp);
+      else
+	{
+	  dest->sp_pwdp = buffer;
+	  strcpy (dest->sp_pwdp, src->sp_pwdp);
+	  buffer += strlen (dest->sp_pwdp) + 1;
+	  buflen = buflen - (strlen (dest->sp_pwdp) + 1);
+	}
+    }
+  if (src->sp_lstchg != 0)
+    dest->sp_lstchg = src->sp_lstchg;
+  if (src->sp_min != 0)
+    dest->sp_min = src->sp_min;
+  if (src->sp_max != 0)
+    dest->sp_max = src->sp_max;
+  if (src->sp_warn != -1)
+    dest->sp_warn = src->sp_warn;
+  if (src->sp_inact != -1)
+    dest->sp_inact = src->sp_inact;
+  if (src->sp_expire != -1)
+    dest->sp_expire = src->sp_expire;
+  if (src->sp_flag != ~0ul)
+    dest->sp_flag = src->sp_flag;
+}
+
+static enum nss_status
+internal_setspent (ent_t *ent, int stayopen, int needent)
+{
+  enum nss_status status = NSS_STATUS_SUCCESS;
+
+  ent->first = ent->netgroup = 0;
+  ent->files = true;
+
+  /* If something was left over free it.  */
+  if (ent->netgroup)
+    __internal_endnetgrent (&ent->netgrdata);
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  if (ent->stream == NULL)
+    {
+      ent->stream = fopen ("/etc/shadow", "rme");
+
+      if (ent->stream == NULL)
+	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+      else
+	/* We take care of locking ourself.  */
+	__fsetlocking (ent->stream, FSETLOCKING_BYCALLER);
+    }
+  else
+    rewind (ent->stream);
+
+  give_spwd_free (&ent->pwd);
+
+  if (needent && status == NSS_STATUS_SUCCESS && nss_setspent)
+    ent->setent_status = nss_setspent (stayopen);
+
+  return status;
+}
+
+
+enum nss_status
+_nss_compat_setspent (int stayopen)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  result = internal_setspent (&ext_ent, stayopen, 1);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static enum nss_status
+internal_endspent (ent_t *ent)
+{
+  if (ent->stream != NULL)
+    {
+      fclose (ent->stream);
+      ent->stream = NULL;
+    }
+
+  if (ent->netgroup)
+    __internal_endnetgrent (&ent->netgrdata);
+
+  ent->first = ent->netgroup = false;
+  ent->files = true;
+
+  if (ent->blacklist.data != NULL)
+    {
+      ent->blacklist.current = 1;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+    }
+  else
+    ent->blacklist.current = 0;
+
+  give_spwd_free (&ent->pwd);
+
+  return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_compat_endspent (void)
+{
+  enum nss_status result;
+
+  __libc_lock_lock (lock);
+
+  if (nss_endspent)
+    nss_endspent ();
+
+  result = internal_endspent (&ext_ent);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static enum nss_status
+getspent_next_nss_netgr (const char *name, struct spwd *result, ent_t *ent,
+			 char *group, char *buffer, size_t buflen,
+			 int *errnop)
+{
+  char *curdomain = NULL, *host, *user, *domain, *p2;
+  size_t p2len;
+
+  if (!nss_getspnam_r)
+    return NSS_STATUS_UNAVAIL;
+
+  /* If the setpwent call failed, say so.  */
+  if (ent->setent_status != NSS_STATUS_SUCCESS)
+    return ent->setent_status;
+
+  if (ent->first)
+    {
+      memset (&ent->netgrdata, 0, sizeof (struct __netgrent));
+      __internal_setnetgrent (group, &ent->netgrdata);
+      ent->first = false;
+    }
+
+  while (1)
+    {
+      enum nss_status status;
+
+      status = __internal_getnetgrent_r (&host, &user, &domain,
+					 &ent->netgrdata, buffer, buflen,
+					 errnop);
+      if (status != 1)
+	{
+	  __internal_endnetgrent (&ent->netgrdata);
+	  ent->netgroup = false;
+	  give_spwd_free (&ent->pwd);
+	  return NSS_STATUS_RETURN;
+	}
+
+      if (user == NULL || user[0] == '-')
+	continue;
+
+      if (domain != NULL)
+	{
+	  if (curdomain == NULL
+	      && __nss_get_default_domain (&curdomain) != 0)
+	    {
+	      __internal_endnetgrent (&ent->netgrdata);
+	      ent->netgroup = false;
+	      give_spwd_free (&ent->pwd);
+	      return NSS_STATUS_UNAVAIL;
+	    }
+	  if (strcmp (curdomain, domain) != 0)
+	    continue;
+	}
+
+      /* If name != NULL, we are called from getpwnam */
+      if (name != NULL)
+	if (strcmp (user, name) != 0)
+	  continue;
+
+      p2len = spwd_need_buflen (&ent->pwd);
+      if (p2len > buflen)
+	{
+	  *errnop = ERANGE;
+	  return NSS_STATUS_TRYAGAIN;
+	}
+      p2 = buffer + (buflen - p2len);
+      buflen -= p2len;
+
+      if (nss_getspnam_r (user, result, buffer, buflen, errnop) !=
+	  NSS_STATUS_SUCCESS)
+	continue;
+
+      if (!in_blacklist (result->sp_namp, strlen (result->sp_namp), ent))
+	{
+	  /* Store the User in the blacklist for possible the "+" at the
+	     end of /etc/passwd */
+	  blacklist_store_name (result->sp_namp, ent);
+	  copy_spwd_changes (result, &ent->pwd, p2, p2len);
+	  break;
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+static enum nss_status
+getspent_next_nss (struct spwd *result, ent_t *ent,
+		   char *buffer, size_t buflen, int *errnop)
+{
+  enum nss_status status;
+  char *p2;
+  size_t p2len;
+
+  if (!nss_getspent_r)
+    return NSS_STATUS_UNAVAIL;
+
+  p2len = spwd_need_buflen (&ent->pwd);
+  if (p2len > buflen)
+    {
+      *errnop = ERANGE;
+      return NSS_STATUS_TRYAGAIN;
+    }
+  p2 = buffer + (buflen - p2len);
+  buflen -= p2len;
+  do
+    {
+      if ((status = nss_getspent_r (result, buffer, buflen, errnop)) !=
+	  NSS_STATUS_SUCCESS)
+	return status;
+    }
+  while (in_blacklist (result->sp_namp, strlen (result->sp_namp), ent));
+
+  copy_spwd_changes (result, &ent->pwd, p2, p2len);
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+/* This function handle the +user entrys in /etc/shadow */
+static enum nss_status
+getspnam_plususer (const char *name, struct spwd *result, ent_t *ent,
+		   char *buffer, size_t buflen, int *errnop)
+{
+  if (!nss_getspnam_r)
+    return NSS_STATUS_UNAVAIL;
+
+  struct spwd pwd;
+  memset (&pwd, '\0', sizeof (struct spwd));
+  pwd.sp_warn = -1;
+  pwd.sp_inact = -1;
+  pwd.sp_expire = -1;
+  pwd.sp_flag = ~0ul;
+
+  copy_spwd_changes (&pwd, result, NULL, 0);
+
+  size_t plen = spwd_need_buflen (&pwd);
+  if (plen > buflen)
+    {
+      *errnop = ERANGE;
+      return NSS_STATUS_TRYAGAIN;
+    }
+  char *p = buffer + (buflen - plen);
+  buflen -= plen;
+
+  enum nss_status status = nss_getspnam_r (name, result, buffer, buflen,
+					   errnop);
+  if (status != NSS_STATUS_SUCCESS)
+    return status;
+
+  if (in_blacklist (result->sp_namp, strlen (result->sp_namp), ent))
+    return NSS_STATUS_NOTFOUND;
+
+  copy_spwd_changes (result, &pwd, p, plen);
+  give_spwd_free (&pwd);
+  /* We found the entry.  */
+  return NSS_STATUS_SUCCESS;
+}
+
+
+static enum nss_status
+getspent_next_file (struct spwd *result, ent_t *ent,
+		    char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+  while (1)
+    {
+      fpos_t pos;
+      int parse_res = 0;
+      char *p;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || __builtin_expect (buffer[buflen - 1] != '\xff', 0))
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#'	/* Ignore empty and comment lines.  */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     || !(parse_res = _nss_files_parse_spent (p, result, data,
+						      buflen, errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      if (result->sp_namp[0] != '+' && result->sp_namp[0] != '-')
+	/* This is a real entry.  */
+	break;
+
+      /* -@netgroup */
+      if (result->sp_namp[0] == '-' && result->sp_namp[1] == '@'
+	  && result->sp_namp[2] != '\0')
+	{
+	  /* XXX Do not use fixed length buffers.  */
+	  char buf2[1024];
+	  char *user, *host, *domain;
+	  struct __netgrent netgrdata;
+
+	  memset (&netgrdata, 0, sizeof (struct __netgrent));
+	  __internal_setnetgrent (&result->sp_namp[2], &netgrdata);
+	  while (__internal_getnetgrent_r (&host, &user, &domain,
+					   &netgrdata, buf2, sizeof (buf2),
+					   errnop))
+	    {
+	      if (user != NULL && user[0] != '-')
+		blacklist_store_name (user, ent);
+	    }
+	  __internal_endnetgrent (&netgrdata);
+	  continue;
+	}
+
+      /* +@netgroup */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] == '@'
+	  && result->sp_namp[2] != '\0')
+	{
+	  int status;
+
+	  ent->netgroup = true;
+	  ent->first = true;
+	  copy_spwd_changes (&ent->pwd, result, NULL, 0);
+
+	  status = getspent_next_nss_netgr (NULL, result, ent,
+					    &result->sp_namp[2],
+					    buffer, buflen, errnop);
+	  if (status == NSS_STATUS_RETURN)
+	    continue;
+	  else
+	    return status;
+	}
+
+      /* -user */
+      if (result->sp_namp[0] == '-' && result->sp_namp[1] != '\0'
+	  && result->sp_namp[1] != '@')
+	{
+	  blacklist_store_name (&result->sp_namp[1], ent);
+	  continue;
+	}
+
+      /* +user */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] != '\0'
+	  && result->sp_namp[1] != '@')
+	{
+	  size_t len = strlen (result->sp_namp);
+	  char buf[len];
+	  enum nss_status status;
+
+	  /* Store the User in the blacklist for the "+" at the end of
+	     /etc/passwd */
+	  memcpy (buf, &result->sp_namp[1], len);
+	  status = getspnam_plususer (&result->sp_namp[1], result, ent,
+				      buffer, buflen, errnop);
+	  blacklist_store_name (buf, ent);
+
+	  if (status == NSS_STATUS_SUCCESS)	/* We found the entry. */
+	    break;
+	  /* We couldn't parse the entry */
+	  else if (status == NSS_STATUS_RETURN
+		   /* entry doesn't exist */
+		   || status == NSS_STATUS_NOTFOUND)
+	    continue;
+	  else
+	    {
+	      if (status == NSS_STATUS_TRYAGAIN)
+		{
+		  fsetpos (ent->stream, &pos);
+		  *errnop = ERANGE;
+		}
+	      return status;
+	    }
+	}
+
+      /* +:... */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] == '\0')
+	{
+	  ent->files = false;
+	  ent->first = true;
+	  copy_spwd_changes (&ent->pwd, result, NULL, 0);
+
+	  return getspent_next_nss (result, ent, buffer, buflen, errnop);
+	}
+    }
+
+  return NSS_STATUS_SUCCESS;
+}
+
+
+static enum nss_status
+internal_getspent_r (struct spwd *pw, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  if (ent->netgroup)
+    {
+      enum nss_status status;
+
+      /* We are searching members in a netgroup */
+      /* Since this is not the first call, we don't need the group name */
+      status = getspent_next_nss_netgr (NULL, pw, ent, NULL, buffer,
+					buflen, errnop);
+
+      if (status == NSS_STATUS_RETURN)
+	return getspent_next_file (pw, ent, buffer, buflen, errnop);
+      else
+	return status;
+    }
+  else if (ent->files)
+    return getspent_next_file (pw, ent, buffer, buflen, errnop);
+  else
+    return getspent_next_nss (pw, ent, buffer, buflen, errnop);
+}
+
+
+enum nss_status
+_nss_compat_getspent_r (struct spwd *pwd, char *buffer, size_t buflen,
+			int *errnop)
+{
+  enum nss_status result = NSS_STATUS_SUCCESS;
+
+  __libc_lock_lock (lock);
+
+  /* Be prepared that the setpwent function was not called before.  */
+  if (ni == NULL)
+    init_nss_interface ();
+
+  if (ext_ent.stream == NULL)
+    result = internal_setspent (&ext_ent, 1, 1);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getspent_r (pwd, &ext_ent, buffer, buflen, errnop);
+
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+/* Searches in /etc/passwd and the NIS/NIS+ map for a special user */
+static enum nss_status
+internal_getspnam_r (const char *name, struct spwd *result, ent_t *ent,
+		     char *buffer, size_t buflen, int *errnop)
+{
+  struct parser_data *data = (void *) buffer;
+
+  while (1)
+    {
+      fpos_t pos;
+      char *p;
+      int parse_res;
+
+      do
+	{
+	  /* We need at least 3 characters for one line.  */
+	  if (__glibc_unlikely (buflen < 3))
+	    {
+	    erange:
+	      *errnop = ERANGE;
+	      return NSS_STATUS_TRYAGAIN;
+	    }
+
+	  fgetpos (ent->stream, &pos);
+	  buffer[buflen - 1] = '\xff';
+	  p = fgets_unlocked (buffer, buflen, ent->stream);
+	  if (p == NULL && feof_unlocked (ent->stream))
+	    return NSS_STATUS_NOTFOUND;
+
+	  if (p == NULL || buffer[buflen - 1] != '\xff')
+	    {
+	    erange_reset:
+	      fsetpos (ent->stream, &pos);
+	      goto erange;
+	    }
+
+          /* Terminate the line for any case.  */
+	  buffer[buflen - 1] = '\0';
+
+	  /* Skip leading blanks.  */
+	  while (isspace (*p))
+	    ++p;
+	}
+      while (*p == '\0' || *p == '#' ||	/* Ignore empty and comment lines.  */
+	     /* Parse the line.  If it is invalid, loop to
+	        get the next line of the file to parse.  */
+	     !(parse_res = _nss_files_parse_spent (p, result, data, buflen,
+						   errnop)));
+
+      if (__glibc_unlikely (parse_res == -1))
+	/* The parser ran out of space.  */
+	goto erange_reset;
+
+      /* This is a real entry.  */
+      if (result->sp_namp[0] != '+' && result->sp_namp[0] != '-')
+	{
+	  if (strcmp (result->sp_namp, name) == 0)
+	    return NSS_STATUS_SUCCESS;
+	  else
+	    continue;
+	}
+
+      /* -@netgroup */
+      /* If the loaded NSS module does not support this service, add
+         all users from a +@netgroup entry to the blacklist, too.  */
+      if (result->sp_namp[0] == '-' && result->sp_namp[1] == '@'
+	  && result->sp_namp[2] != '\0')
+	{
+	  if (innetgr (&result->sp_namp[2], NULL, name, NULL))
+	    return NSS_STATUS_NOTFOUND;
+	  continue;
+	}
+
+      /* +@netgroup */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] == '@'
+	  && result->sp_namp[2] != '\0')
+	{
+	  enum nss_status status;
+
+	  if (innetgr (&result->sp_namp[2], NULL, name, NULL))
+	    {
+	      status = getspnam_plususer (name, result, ent, buffer,
+					  buflen, errnop);
+
+	      if (status == NSS_STATUS_RETURN)
+		continue;
+
+	      return status;
+	    }
+	  continue;
+	}
+
+      /* -user */
+      if (result->sp_namp[0] == '-' && result->sp_namp[1] != '\0'
+	  && result->sp_namp[1] != '@')
+	{
+	  if (strcmp (&result->sp_namp[1], name) == 0)
+	    return NSS_STATUS_NOTFOUND;
+	  else
+	    continue;
+	}
+
+      /* +user */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] != '\0'
+	  && result->sp_namp[1] != '@')
+	{
+	  if (strcmp (name, &result->sp_namp[1]) == 0)
+	    {
+	      enum nss_status status;
+
+	      status = getspnam_plususer (name, result, ent,
+					  buffer, buflen, errnop);
+
+	      if (status == NSS_STATUS_RETURN)
+		/* We couldn't parse the entry */
+		return NSS_STATUS_NOTFOUND;
+	      else
+		return status;
+	    }
+	}
+
+      /* +:... */
+      if (result->sp_namp[0] == '+' && result->sp_namp[1] == '\0')
+	{
+	  enum nss_status status;
+
+	  status = getspnam_plususer (name, result, ent,
+				      buffer, buflen, errnop);
+
+	  if (status == NSS_STATUS_SUCCESS)
+	    /* We found the entry. */
+            break;
+          else if (status == NSS_STATUS_RETURN)
+	    /* We couldn't parse the entry */
+            return NSS_STATUS_NOTFOUND;
+	  else
+	    return status;
+	}
+    }
+  return NSS_STATUS_SUCCESS;
+}
+
+
+enum nss_status
+_nss_compat_getspnam_r (const char *name, struct spwd *pwd,
+			char *buffer, size_t buflen, int *errnop)
+{
+  enum nss_status result;
+  ent_t ent = { false, true, false, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0},
+		{ NULL, NULL, 0, 0, 0, 0, 0, 0, 0}};
+
+  if (name[0] == '-' || name[0] == '+')
+    return NSS_STATUS_NOTFOUND;
+
+  __libc_lock_lock (lock);
+
+  if (ni == NULL)
+    init_nss_interface ();
+
+  __libc_lock_unlock (lock);
+
+  result = internal_setspent (&ent, 0, 0);
+
+  if (result == NSS_STATUS_SUCCESS)
+    result = internal_getspnam_r (name, pwd, &ent, buffer, buflen, errnop);
+
+  internal_endspent (&ent);
+
+  return result;
+}
+
+
+/* Support routines for remembering -@netgroup and -user entries.
+   The names are stored in a single string with `|' as separator. */
+static void
+blacklist_store_name (const char *name, ent_t *ent)
+{
+  int namelen = strlen (name);
+  char *tmp;
+
+  /* first call, setup cache */
+  if (ent->blacklist.size == 0)
+    {
+      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
+      ent->blacklist.data = malloc (ent->blacklist.size);
+      if (ent->blacklist.data == NULL)
+	return;
+      ent->blacklist.data[0] = '|';
+      ent->blacklist.data[1] = '\0';
+      ent->blacklist.current = 1;
+    }
+  else
+    {
+      if (in_blacklist (name, namelen, ent))
+	return;			/* no duplicates */
+
+      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
+	{
+	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
+	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
+	  if (tmp == NULL)
+	    {
+	      free (ent->blacklist.data);
+	      ent->blacklist.size = 0;
+	      return;
+	    }
+	  ent->blacklist.data = tmp;
+	}
+    }
+
+  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
+  *tmp++ = '|';
+  *tmp = '\0';
+  ent->blacklist.current += namelen + 1;
+
+  return;
+}
+
+
+/* Returns whether ent->blacklist contains name.  */
+static bool
+in_blacklist (const char *name, int namelen, ent_t *ent)
+{
+  char buf[namelen + 3];
+  char *cp;
+
+  if (ent->blacklist.data == NULL)
+    return false;
+
+  buf[0] = '|';
+  cp = stpcpy (&buf[1], name);
+  *cp++ = '|';
+  *cp = '\0';
+  return strstr (ent->blacklist.data, buf) != NULL;
+}
diff --git a/nss/nss_compat/nisdomain.c b/nss/nss_compat/nisdomain.c
new file mode 100644
index 0000000..220ae27
--- /dev/null
+++ b/nss/nss_compat/nisdomain.c
@@ -0,0 +1,58 @@
+/* Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <libc-lock.h>
+#include "nisdomain.h"
+
+#define MAXDOMAINNAMELEN 1024
+
+static char domainname[MAXDOMAINNAMELEN];
+
+__libc_lock_define_initialized (static, domainname_lock)
+
+int
+__nss_get_default_domain (char **outdomain)
+{
+  int result = 0;
+  *outdomain = NULL;
+
+  __libc_lock_lock (domainname_lock);
+
+  if (domainname[0] != '\0')
+    {
+      if (getdomainname (domainname, MAXDOMAINNAMELEN) < 0)
+	result = errno;
+      else if (strcmp (domainname, "(none)") == 0)
+	{
+	  /* If domainname is not set, some systems will return "(none)" */
+	  domainname[0] = '\0';
+	  result = ENOENT;
+	}
+      else
+	*outdomain = domainname;
+    }
+  else
+    *outdomain = domainname;
+
+  __libc_lock_unlock (domainname_lock);
+
+  return result;
+}
diff --git a/nss/nss_compat/nisdomain.h b/nss/nss_compat/nisdomain.h
new file mode 100644
index 0000000..314f3f7
--- /dev/null
+++ b/nss/nss_compat/nisdomain.h
@@ -0,0 +1,20 @@
+/* Copyright (C) 2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* Set OUTDOMAIN to a pointer to the current NIS domain name, or NULL if
+   not set.  Return zero on success, an error number on failure.  */
+extern int __nss_get_default_domain (char **outdomain);