nsswitch: use new internal API (core)

Core changes to switch the NSS internals to use the new API.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 33 insertions, 776 deletions

diff --git a/nss/nsswitch.c b/nss/nsswitch.c
index 8d7b69d4bc..40109c744d 100644
--- a/nss/nsswitch.c
+++ b/nss/nsswitch.c
@@ -32,6 +32,7 @@
 #include <netinet/ether.h>
 #include <pwd.h>
 #include <shadow.h>
+#include <unistd.h>
 
 #if !defined DO_STATIC_NSS || defined SHARED
 # include <gnu/lib-names.h>
@@ -42,36 +43,20 @@
 #include <sysdep.h>
 #include <config.h>
 
-/* Prototypes for the local functions.  */
-static name_database *nss_parse_file (const char *fname);
-static name_database_entry *nss_getline (char *line);
-static service_user *nss_parse_service_list (const char *line);
-#if !defined DO_STATIC_NSS || defined SHARED
-static service_library *nss_new_service (name_database *database,
-					 const char *name);
-#endif
-
-
 /* Declare external database variables.  */
 #define DEFINE_DATABASE(name)						      \
-  service_user *__nss_##name##_database attribute_hidden;		      \
+  nss_action_list __nss_##name##_database attribute_hidden;		      \
   weak_extern (__nss_##name##_database)
 #include "databases.def"
 #undef DEFINE_DATABASE
 
-/* Structure to map database name to variable.  */
-static const struct
-{
-  const char name[10];
-  service_user **dbp;
-} databases[] =
-{
-#define DEFINE_DATABASE(name)						      \
-  { #name, &__nss_##name##_database },
-#include "databases.def"
+
 #undef DEFINE_DATABASE
+#define DEFINE_DATABASE(name)  #name,
+static const char * database_names[] = {
+#include "databases.def"
+  NULL
 };
-#define ndatabases (sizeof (databases) / sizeof (databases[0]))
 
 #ifdef USE_NSCD
 /* Flags whether custom rules for database is set.  */
@@ -79,103 +64,33 @@ bool __nss_database_custom[NSS_DBSIDX_max];
 #endif
 
 
-__libc_lock_define_initialized (static, lock)
-
-#if !defined DO_STATIC_NSS || defined SHARED
-/* String with revision number of the shared object files.  */
-static const char *const __nss_shlib_revision = LIBNSS_FILES_SO + 15;
-#endif
-
-/* The root of the whole data base.  */
-static name_database *service_table;
-
-/* List of default service lists that were generated by glibc because
-   /etc/nsswitch.conf did not provide a value.
-   The list is only maintained so we can free such service lists in
-   __libc_freeres.  */
-static name_database_entry *defconfig_entries;
-
-
-#if defined USE_NSCD && (!defined DO_STATIC_NSS || defined SHARED)
-/* Nonzero if this is the nscd process.  */
-static bool is_nscd;
-/* The callback passed to the init functions when nscd is used.  */
-static void (*nscd_init_cb) (size_t, struct traced_file *);
-#endif
-
+/*__libc_lock_define_initialized (static, lock)*/
 
 /* -1 == database not found
     0 == database entry pointer stored */
 int
 __nss_database_lookup2 (const char *database, const char *alternate_name,
-			const char *defconfig, service_user **ni)
+			const char *defconfig, nss_action_list *ni)
 {
-  /* Prevent multiple threads to change the service table.  */
-  __libc_lock_lock (lock);
+  int database_id;
 
-  /* Reconsider database variable in case some other thread called
-     `__nss_configure_lookup' while we waited for the lock.  */
-  if (*ni != NULL)
-    {
-      __libc_lock_unlock (lock);
-      return 0;
-    }
+  for (database_id = 0; database_names[database_id]; database_id++)
+    if (strcmp (database_names[database_id], database) == 0)
+	break;
 
-  /* Are we initialized yet?  */
-  if (service_table == NULL)
-    /* Read config file.  */
-    service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
+  if (database_names[database_id] == NULL)
+    return -1;
 
-  /* Test whether configuration data is available.  */
-  if (service_table != NULL)
+  if (__nss_database_get (database_id, ni))
     {
-      /* Return first `service_user' entry for DATABASE.  */
-      name_database_entry *entry;
-
-      /* XXX Could use some faster mechanism here.  But each database is
-	 only requested once and so this might not be critical.  */
-      for (entry = service_table->entry; entry != NULL; entry = entry->next)
-	if (strcmp (database, entry->name) == 0)
-	  *ni = entry->service;
-
-      if (*ni == NULL && alternate_name != NULL)
-	/* We haven't found an entry so far.  Try to find it with the
-	   alternative name.  */
-	for (entry = service_table->entry; entry != NULL; entry = entry->next)
-	  if (strcmp (alternate_name, entry->name) == 0)
-	    *ni = entry->service;
+      /* Success.  */
+      return 0;
     }
-
-  /* No configuration data is available, either because nsswitch.conf
-     doesn't exist or because it doesn't have a line for this database.
-
-     DEFCONFIG specifies the default service list for this database,
-     or null to use the most common default.  */
-  if (*ni == NULL)
+  else
     {
-      *ni = nss_parse_service_list (defconfig ?: "files");
-      if (*ni != NULL)
-	{
-	  /* Record the memory we've just allocated in defconfig_entries list,
-	     so we can free it later.  */
-	  name_database_entry *entry;
-
-	  /* Allocate ENTRY plus size of name (1 here).  */
-	  entry = (name_database_entry *) malloc (sizeof (*entry) + 1);
-
-	  if (entry != NULL)
-	    {
-	      entry->next = defconfig_entries;
-	      entry->service = *ni;
-	      entry->name[0] = '\0';
-	      defconfig_entries = entry;
-	    }
-	}
+      /* Failure.  */
+      return -1;
     }
-
-  __libc_lock_unlock (lock);
-
-  return *ni != NULL ? 0 : -1;
 }
 libc_hidden_def (__nss_database_lookup2)
 
@@ -184,7 +99,7 @@ libc_hidden_def (__nss_database_lookup2)
     0 == function found
     1 == finished */
 int
-__nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name,
+__nss_lookup (nss_action_list *ni, const char *fct_name, const char *fct2_name,
 	      void **fctp)
 {
   *fctp = __nss_lookup_function (*ni, fct_name);
@@ -193,16 +108,16 @@ __nss_lookup (service_user **ni, const char *fct_name, const char *fct2_name,
 
   while (*fctp == NULL
 	 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
-	 && (*ni)->next != NULL)
+	 && (*ni)[1].module != NULL)
     {
-      *ni = (*ni)->next;
+      ++(*ni);
 
       *fctp = __nss_lookup_function (*ni, fct_name);
       if (*fctp == NULL && fct2_name != NULL)
 	*fctp = __nss_lookup_function (*ni, fct2_name);
     }
 
-  return *fctp != NULL ? 0 : (*ni)->next == NULL ? 1 : -1;
+  return *fctp != NULL ? 0 : (*ni)[1].module == NULL ? 1 : -1;
 }
 libc_hidden_def (__nss_lookup)
 
@@ -211,7 +126,7 @@ libc_hidden_def (__nss_lookup)
     0 == adjusted for next function
     1 == finished */
 int
-__nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
+__nss_next2 (nss_action_list *ni, const char *fct_name, const char *fct2_name,
 	     void **fctp, int status, int all_values)
 {
   if (all_values)
@@ -233,12 +148,12 @@ __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
 	 return 1;
     }
 
-  if ((*ni)->next == NULL)
+  if ((*ni)[1].module == NULL)
     return -1;
 
   do
     {
-      *ni = (*ni)->next;
+      ++(*ni);
 
       *fctp = __nss_lookup_function (*ni, fct_name);
       if (*fctp == NULL && fct2_name != NULL)
@@ -246,675 +161,17 @@ __nss_next2 (service_user **ni, const char *fct_name, const char *fct2_name,
     }
   while (*fctp == NULL
 	 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
-	 && (*ni)->next != NULL);
+	 && (*ni)[1].module != NULL);
 
   return *fctp != NULL ? 0 : -1;
 }
 libc_hidden_def (__nss_next2)
 
-int
-__nss_configure_lookup (const char *dbname, const char *service_line)
-{
-  service_user *new_db;
-  size_t cnt;
-
-  for (cnt = 0; cnt < ndatabases; ++cnt)
-    {
-      int cmp = strcmp (dbname, databases[cnt].name);
-      if (cmp == 0)
-	break;
-      if (cmp < 0)
-	{
-	  __set_errno (EINVAL);
-	  return -1;
-	}
-    }
-
-  if (cnt == ndatabases)
-    {
-      __set_errno (EINVAL);
-      return -1;
-    }
-
-  /* Test whether it is really used.  */
-  if (databases[cnt].dbp == NULL)
-    /* Nothing to do, but we could do.  */
-    return 0;
-
-  /* Try to generate new data.  */
-  new_db = nss_parse_service_list (service_line);
-  if (new_db == NULL)
-    {
-      /* Illegal service specification.  */
-      __set_errno (EINVAL);
-      return -1;
-    }
-
-  /* Prevent multiple threads to change the service table.  */
-  __libc_lock_lock (lock);
-
-  /* Install new rules.  */
-  *databases[cnt].dbp = new_db;
-#ifdef USE_NSCD
-  __nss_database_custom[cnt] = true;
-#endif
-
-  __libc_lock_unlock (lock);
-
-  return 0;
-}
-
-
-/* Comparison function for searching NI->known tree.  */
-static int
-known_compare (const void *p1, const void *p2)
-{
-  return p1 == p2 ? 0 : strcmp (*(const char *const *) p1,
-				*(const char *const *) p2);
-}
-
-
-#if !defined DO_STATIC_NSS || defined SHARED
-/* Load library.  */
-static int
-nss_load_library (service_user *ni)
-{
-  if (ni->library == NULL)
-    {
-      /* This service has not yet been used.  Fetch the service
-	 library for it, creating a new one if need be.  If there
-	 is no service table from the file, this static variable
-	 holds the head of the service_library list made from the
-	 default configuration.  */
-      static name_database default_table;
-      ni->library = nss_new_service (service_table ?: &default_table,
-				     ni->name);
-      if (ni->library == NULL)
-	return -1;
-    }
-
-  if (ni->library->lib_handle == NULL)
-    {
-      /* Load the shared library.  */
-      size_t shlen = (7 + strlen (ni->name) + 3
-		      + strlen (__nss_shlib_revision) + 1);
-      int saved_errno = errno;
-      char shlib_name[shlen];
-
-      /* Construct shared object name.  */
-      __stpcpy (__stpcpy (__stpcpy (__stpcpy (shlib_name,
-					      "libnss_"),
-				    ni->name),
-			  ".so"),
-		__nss_shlib_revision);
-
-      ni->library->lib_handle = __libc_dlopen (shlib_name);
-      if (ni->library->lib_handle == NULL)
-	{
-	  /* Failed to load the library.  */
-	  ni->library->lib_handle = (void *) -1l;
-	  __set_errno (saved_errno);
-	}
-# ifdef USE_NSCD
-      else if (is_nscd)
-	{
-	  /* Call the init function when nscd is used.  */
-	  size_t initlen = (5 + strlen (ni->name)
-			    + strlen ("_init") + 1);
-	  char init_name[initlen];
-
-	  /* Construct the init function name.  */
-	  __stpcpy (__stpcpy (__stpcpy (init_name,
-					"_nss_"),
-			      ni->name),
-		    "_init");
-
-	  /* Find the optional init function.  */
-	  void (*ifct) (void (*) (size_t, struct traced_file *))
-	    = __libc_dlsym (ni->library->lib_handle, init_name);
-	  if (ifct != NULL)
-	    {
-	      void (*cb) (size_t, struct traced_file *) = nscd_init_cb;
-#  ifdef PTR_DEMANGLE
-	      PTR_DEMANGLE (cb);
-#  endif
-	      ifct (cb);
-	    }
-	}
-# endif
-    }
-
-  return 0;
-}
-#endif
-
-
 void *
-__nss_lookup_function (service_user *ni, const char *fct_name)
-{
-  void **found, *result;
-
-  /* We now modify global data.  Protect it.  */
-  __libc_lock_lock (lock);
-
-  /* Search the tree of functions previously requested.  Data in the
-     tree are `known_function' structures, whose first member is a
-     `const char *', the lookup key.  The search returns a pointer to
-     the tree node structure; the first member of the is a pointer to
-     our structure (i.e. what will be a `known_function'); since the
-     first member of that is the lookup key string, &FCT_NAME is close
-     enough to a pointer to our structure to use as a lookup key that
-     will be passed to `known_compare' (above).  */
-
-  found = __tsearch (&fct_name, &ni->known, &known_compare);
-  if (found == NULL)
-    /* This means out-of-memory.  */
-    result = NULL;
-  else if (*found != &fct_name)
-    {
-      /* The search found an existing structure in the tree.  */
-      result = ((known_function *) *found)->fct_ptr;
-#ifdef PTR_DEMANGLE
-      PTR_DEMANGLE (result);
-#endif
-    }
-  else
-    {
-      /* This name was not known before.  Now we have a node in the tree
-	 (in the proper sorted position for FCT_NAME) that points to
-	 &FCT_NAME instead of any real `known_function' structure.
-	 Allocate a new structure and fill it in.  */
-
-      known_function *known = malloc (sizeof *known);
-      if (! known)
-	{
-#if !defined DO_STATIC_NSS || defined SHARED
-	remove_from_tree:
-#endif
-	  /* Oops.  We can't instantiate this node properly.
-	     Remove it from the tree.  */
-	  __tdelete (&fct_name, &ni->known, &known_compare);
-	  free (known);
-	  result = NULL;
-	}
-      else
-	{
-	  /* Point the tree node at this new structure.  */
-	  *found = known;
-	  known->fct_name = fct_name;
-
-#if !defined DO_STATIC_NSS || defined SHARED
-	  /* Load the appropriate library.  */
-	  if (nss_load_library (ni) != 0)
-	    /* This only happens when out of memory.  */
-	    goto remove_from_tree;
-
-	  if (ni->library->lib_handle == (void *) -1l)
-	    /* Library not found => function not found.  */
-	    result = NULL;
-	  else
-	    {
-	      /* Get the desired function.  */
-	      size_t namlen = (5 + strlen (ni->name) + 1
-			       + strlen (fct_name) + 1);
-	      char name[namlen];
-
-	      /* Construct the function name.  */
-	      __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"),
-					    ni->name),
-				  "_"),
-			fct_name);
-
-	      /* Look up the symbol.  */
-	      result = __libc_dlsym (ni->library->lib_handle, name);
-	    }
-#else
-	  /* We can't get function address dynamically in static linking. */
-	  {
-# define DEFINE_ENT(h,nm)						      \
-	    { #h"_get"#nm"ent_r", _nss_##h##_get##nm##ent_r },		      \
-	    { #h"_end"#nm"ent", _nss_##h##_end##nm##ent },		      \
-	    { #h"_set"#nm"ent", _nss_##h##_set##nm##ent },
-# define DEFINE_GET(h,nm)						      \
-	    { #h"_get"#nm"_r", _nss_##h##_get##nm##_r },
-# define DEFINE_GETBY(h,nm,ky)						      \
-	    { #h"_get"#nm"by"#ky"_r", _nss_##h##_get##nm##by##ky##_r },
-	    static struct fct_tbl { const char *fname; void *fp; } *tp, tbl[] =
-	      {
-# include "function.def"
-		{ NULL, NULL }
-	      };
-	    size_t namlen = (5 + strlen (ni->name) + 1
-			     + strlen (fct_name) + 1);
-	    char name[namlen];
-
-	    /* Construct the function name.  */
-	    __stpcpy (__stpcpy (__stpcpy (name, ni->name),
-				"_"),
-		      fct_name);
-
-	    result = NULL;
-	    for (tp = &tbl[0]; tp->fname; tp++)
-	      if (strcmp (tp->fname, name) == 0)
-		{
-		  result = tp->fp;
-		  break;
-		}
-	  }
-#endif
-
-	  /* Remember function pointer for later calls.  Even if null, we
-	     record it so a second try needn't search the library again.  */
-	  known->fct_ptr = result;
-#ifdef PTR_MANGLE
-	  PTR_MANGLE (known->fct_ptr);
-#endif
-	}
-    }
-
-  /* Remove the lock.  */
-  __libc_lock_unlock (lock);
-
-  return result;
-}
-libc_hidden_def (__nss_lookup_function)
-
-
-static name_database *
-nss_parse_file (const char *fname)
+__nss_lookup_function (nss_action_list ni, const char *fct_name)
 {
-  FILE *fp;
-  name_database *result;
-  name_database_entry *last;
-  char *line;
-  size_t len;
-
-  /* Open the configuration file.  */
-  fp = fopen (fname, "rce");
-  if (fp == NULL)
+  if (ni->module == NULL)
     return NULL;
-
-  /* No threads use this stream.  */
-  __fsetlocking (fp, FSETLOCKING_BYCALLER);
-
-  result = (name_database *) malloc (sizeof (name_database));
-  if (result == NULL)
-    {
-      fclose (fp);
-      return NULL;
-    }
-
-  result->entry = NULL;
-  result->library = NULL;
-  last = NULL;
-  line = NULL;
-  len = 0;
-  do
-    {
-      name_database_entry *this;
-      ssize_t n;
-
-      n = __getline (&line, &len, fp);
-      if (n < 0)
-	break;
-      if (line[n - 1] == '\n')
-	line[n - 1] = '\0';
-
-      /* Because the file format does not know any form of quoting we
-	 can search forward for the next '#' character and if found
-	 make it terminating the line.  */
-      *__strchrnul (line, '#') = '\0';
-
-      /* If the line is blank it is ignored.  */
-      if (line[0] == '\0')
-	continue;
-
-      /* Each line completely specifies the actions for a database.  */
-      this = nss_getline (line);
-      if (this != NULL)
-	{
-	  if (last != NULL)
-	    last->next = this;
-	  else
-	    result->entry = this;
-
-	  last = this;
-	}
-    }
-  while (!__feof_unlocked (fp));
-
-  /* Free the buffer.  */
-  free (line);
-  /* Close configuration file.  */
-  fclose (fp);
-
-  return result;
-}
-
-
-/* Read the source names:
-	`( <source> ( "[" "!"? (<status> "=" <action> )+ "]" )? )*'
-   */
-static service_user *
-nss_parse_service_list (const char *line)
-{
-  service_user *result = NULL, **nextp = &result;
-
-  while (1)
-    {
-      service_user *new_service;
-      const char *name;
-
-      while (isspace (line[0]))
-	++line;
-      if (line[0] == '\0')
-	/* No source specified.  */
-	return result;
-
-      /* Read <source> identifier.  */
-      name = line;
-      while (line[0] != '\0' && !isspace (line[0]) && line[0] != '[')
-	++line;
-      if (name == line)
-	return result;
-
-
-      new_service = (service_user *) malloc (sizeof (service_user)
-					     + (line - name + 1));
-      if (new_service == NULL)
-	return result;
-
-      *((char *) __mempcpy (new_service->name, name, line - name)) = '\0';
-
-      /* Set default actions.  */
-      new_service->actions[2 + NSS_STATUS_TRYAGAIN] = NSS_ACTION_CONTINUE;
-      new_service->actions[2 + NSS_STATUS_UNAVAIL] = NSS_ACTION_CONTINUE;
-      new_service->actions[2 + NSS_STATUS_NOTFOUND] = NSS_ACTION_CONTINUE;
-      new_service->actions[2 + NSS_STATUS_SUCCESS] = NSS_ACTION_RETURN;
-      new_service->actions[2 + NSS_STATUS_RETURN] = NSS_ACTION_RETURN;
-      new_service->library = NULL;
-      new_service->known = NULL;
-      new_service->next = NULL;
-
-      while (isspace (line[0]))
-	++line;
-
-      if (line[0] == '[')
-	{
-	  /* Read criterions.  */
-	  do
-	    ++line;
-	  while (line[0] != '\0' && isspace (line[0]));
-
-	  do
-	    {
-	      int not;
-	      enum nss_status status;
-	      lookup_actions action;
-
-	      /* Grok ! before name to mean all statii but that one.  */
-	      not = line[0] == '!';
-	      if (not)
-		++line;
-
-	      /* Read status name.  */
-	      name = line;
-	      while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
-		     && line[0] != ']')
-		++line;
-
-	      /* Compare with known statii.  */
-	      if (line - name == 7)
-		{
-		  if (__strncasecmp (name, "SUCCESS", 7) == 0)
-		    status = NSS_STATUS_SUCCESS;
-		  else if (__strncasecmp (name, "UNAVAIL", 7) == 0)
-		    status = NSS_STATUS_UNAVAIL;
-		  else
-		    goto finish;
-		}
-	      else if (line - name == 8)
-		{
-		  if (__strncasecmp (name, "NOTFOUND", 8) == 0)
-		    status = NSS_STATUS_NOTFOUND;
-		  else if (__strncasecmp (name, "TRYAGAIN", 8) == 0)
-		    status = NSS_STATUS_TRYAGAIN;
-		  else
-		    goto finish;
-		}
-	      else
-		goto finish;
-
-	      while (isspace (line[0]))
-		++line;
-	      if (line[0] != '=')
-		goto finish;
-	      do
-		++line;
-	      while (isspace (line[0]));
-
-	      name = line;
-	      while (line[0] != '\0' && !isspace (line[0]) && line[0] != '='
-		     && line[0] != ']')
-		++line;
-
-	      if (line - name == 6 && __strncasecmp (name, "RETURN", 6) == 0)
-		action = NSS_ACTION_RETURN;
-	      else if (line - name == 8
-		       && __strncasecmp (name, "CONTINUE", 8) == 0)
-		action = NSS_ACTION_CONTINUE;
-	      else if (line - name == 5
-		       && __strncasecmp (name, "MERGE", 5) == 0)
-		action = NSS_ACTION_MERGE;
-	      else
-		goto finish;
-
-	      if (not)
-		{
-		  /* Save the current action setting for this status,
-		     set them all to the given action, and reset this one.  */
-		  const lookup_actions save = new_service->actions[2 + status];
-		  new_service->actions[2 + NSS_STATUS_TRYAGAIN] = action;
-		  new_service->actions[2 + NSS_STATUS_UNAVAIL] = action;
-		  new_service->actions[2 + NSS_STATUS_NOTFOUND] = action;
-		  new_service->actions[2 + NSS_STATUS_SUCCESS] = action;
-		  new_service->actions[2 + status] = save;
-		}
-	      else
-		new_service->actions[2 + status] = action;
-
-	      /* Skip white spaces.  */
-	      while (isspace (line[0]))
-		++line;
-	    }
-	  while (line[0] != ']');
-
-	  /* Skip the ']'.  */
-	  ++line;
-	}
-
-      *nextp = new_service;
-      nextp = &new_service->next;
-      continue;
-
-    finish:
-      free (new_service);
-      return result;
-    }
-}
-
-static name_database_entry *
-nss_getline (char *line)
-{
-  const char *name;
-  name_database_entry *result;
-  size_t len;
-
-  /* Ignore leading white spaces.  ATTENTION: this is different from
-     what is implemented in Solaris.  The Solaris man page says a line
-     beginning with a white space character is ignored.  We regard
-     this as just another misfeature in Solaris.  */
-  while (isspace (line[0]))
-    ++line;
-
-  /* Recognize `<database> ":"'.  */
-  name = line;
-  while (line[0] != '\0' && !isspace (line[0]) && line[0] != ':')
-    ++line;
-  if (line[0] == '\0' || name == line)
-    /* Syntax error.  */
-    return NULL;
-  *line++ = '\0';
-
-  len = strlen (name) + 1;
-
-  result = (name_database_entry *) malloc (sizeof (name_database_entry) + len);
-  if (result == NULL)
-    return NULL;
-
-  /* Save the database name.  */
-  memcpy (result->name, name, len);
-
-  /* Parse the list of services.  */
-  result->service = nss_parse_service_list (line);
-
-  result->next = NULL;
-  return result;
-}
-
-
-#if !defined DO_STATIC_NSS || defined SHARED
-static service_library *
-nss_new_service (name_database *database, const char *name)
-{
-  service_library **currentp = &database->library;
-
-  while (*currentp != NULL)
-    {
-      if (strcmp ((*currentp)->name, name) == 0)
-	return *currentp;
-      currentp = &(*currentp)->next;
-    }
-
-  /* We have to add the new service.  */
-  *currentp = (service_library *) malloc (sizeof (service_library));
-  if (*currentp == NULL)
-    return NULL;
-
-  (*currentp)->name = name;
-  (*currentp)->lib_handle = NULL;
-  (*currentp)->next = NULL;
-
-  return *currentp;
-}
-#endif
-
-
-#if defined SHARED && defined USE_NSCD
-/* Load all libraries for the service.  */
-static void
-nss_load_all_libraries (const char *service, const char *def)
-{
-  service_user *ni = NULL;
-
-  if (__nss_database_lookup2 (service, NULL, def, &ni) == 0)
-    while (ni != NULL)
-      {
-	nss_load_library (ni);
-	ni = ni->next;
-      }
-}
-
-
-/* Called by nscd and nscd alone.  */
-void
-__nss_disable_nscd (void (*cb) (size_t, struct traced_file *))
-{
-# ifdef PTR_MANGLE
-  PTR_MANGLE (cb);
-# endif
-  nscd_init_cb = cb;
-  is_nscd = true;
-
-  /* Find all the relevant modules so that the init functions are called.  */
-  nss_load_all_libraries ("passwd", "files");
-  nss_load_all_libraries ("group", "files");
-  nss_load_all_libraries ("hosts", "dns [!UNAVAIL=return] files");
-  nss_load_all_libraries ("services", NULL);
-
-  /* Disable all uses of NSCD.  */
-  __nss_not_use_nscd_passwd = -1;
-  __nss_not_use_nscd_group = -1;
-  __nss_not_use_nscd_hosts = -1;
-  __nss_not_use_nscd_services = -1;
-  __nss_not_use_nscd_netgroup = -1;
-}
-#endif
-
-static void
-free_database_entries (name_database_entry *entry)
-{
-  while (entry != NULL)
-    {
-      name_database_entry *olde = entry;
-      service_user *service = entry->service;
-
-      while (service != NULL)
-	{
-	  service_user *olds = service;
-
-	  if (service->known != NULL)
-	    __tdestroy (service->known, free);
-
-	  service = service->next;
-	  free (olds);
-	}
-
-      entry = entry->next;
-      free (olde);
-    }
-}
-
-/* Free all resources if necessary.  */
-libc_freeres_fn (free_defconfig)
-{
-  name_database_entry *entry = defconfig_entries;
-
-  if (entry == NULL)
-    /* defconfig was not used.  */
-    return;
-
-  /* Don't disturb ongoing other threads (if there are any).  */
-  defconfig_entries = NULL;
-
-  free_database_entries (entry);
-}
-
-libc_freeres_fn (free_mem)
-{
-  name_database *top = service_table;
-  service_library *library;
-
-  if (top == NULL)
-    /* Maybe we have not read the nsswitch.conf file.  */
-    return;
-
-  /* Don't disturb ongoing other threads (if there are any).  */
-  service_table = NULL;
-
-  free_database_entries (top->entry);
-
-  library = top->library;
-  while (library != NULL)
-    {
-      service_library *oldl = library;
-
-      if (library->lib_handle && library->lib_handle != (void *) -1l)
-	__libc_dlclose (library->lib_handle);
-
-      library = library->next;
-      free (oldl);
-    }
-
-  free (top);
+  return __nss_module_get_function (ni->module, fct_name);
 }
+libc_hidden_def (__nss_lookup_function)