1 files changed, 588 insertions, 0 deletions
diff --git a/nss/nsswitch.c b/nss/nsswitch.c
new file mode 100644
index 0000000000..4c2ccf692f
--- /dev/null
+++ b/nss/nsswitch.c
@@ -0,0 +1,588 @@
+/* Copyright (C) 1996 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <ctype.h>
+#include <dlfcn.h>
+#include <netdb.h>
+#include <libc-lock.h>
+#include <search.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nsswitch.h"
+#include "../elf/link.h"	/* We need some help from ld.so.  */
+
+/* Prototypes for the local functions.  */
+static void nss_init (void);
+static void *nss_lookup_function (service_user *ni, const char *fct_name);
+static int nss_find_entry (struct entry **knownp, const char *key,
+			   void **valp);
+static void nss_insert_entry (struct entry **knownp, const char *key,
+			      void *val);
+static name_database *nss_parse_file (const char *fname);
+static name_database_entry *nss_getline (char *line);
+static service_library *nss_new_service (name_database *database,
+					 const char *name);
+
+
+__libc_lock_define_initialized (static, lock);
+
+
+/* Global variable.  */
+struct __res_state _res;
+
+
+/* Known aliases for service names.  */
+static struct {
+  const char *alias;
+  const char *value;
+} service_alias[] =
+{
+  { "nis+", "nisplus" },
+  { "yp", "nis" }
+};
+
+
+/* Nonzero if the sevices are already initialized.  */
+static int nss_initialized;
+
+
+/* The root of the whole data base.  */
+static name_database *service_table;
+
+
+static void
+nss_init (void)
+{
+  /* Prevent multiple threads to change the service table.  */
+  __libc_lock_lock (lock);
+
+  if (service_table == NULL)
+    service_table = nss_parse_file (_PATH_NSSWITCH_CONF);
+
+  __libc_lock_unlock (lock);
+}
+
+
+/* -1 == database not found
+    0 == database entry pointer stored */
+int
+__nss_database_lookup (const char *database, service_user **ni)
+{
+  /* Return first `service_user' entry for DATABASE.
+     XXX Will use perfect hashing function for known databases.  */
+  name_database_entry *entry;
+
+  /* Test whether configuration data is available.  */
+  if (service_table == NULL)
+    {
+      if (nss_initialized == 0)
+	nss_init ();
+
+      if (service_table == NULL)
+	return -1;
+    }
+
+  /* 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)
+      break;
+
+  if (entry == NULL || (*ni = entry->service) == NULL)
+    return -1;
+
+  return 0;
+}
+
+
+/* -1 == not found
+    0 == adjusted for next function */
+int
+__nss_lookup (service_user **ni, const char *fct_name, void **fctp)
+{
+  *fctp = nss_lookup_function (*ni, fct_name);
+
+  while (*fctp == NULL
+	 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
+	 && (*ni)->next != NULL)
+    {
+      *ni = (*ni)->next;
+
+      *fctp = nss_lookup_function (*ni, fct_name);
+    }
+
+  return *fctp != NULL ? 0 : -1;
+}
+
+
+/* -1 == not found
+    0 == adjusted for next function
+    1 == finished */
+int
+__nss_next (service_user **ni, const char *fct_name, void **fctp, int status,
+	    int all_values)
+{
+  if (all_values)
+    {
+      if (nss_next_action (*ni, NSS_STATUS_TRYAGAIN) == NSS_ACTION_RETURN
+	  && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_RETURN
+	  && nss_next_action (*ni, NSS_STATUS_NOTFOUND) == NSS_ACTION_RETURN
+	  && nss_next_action (*ni, NSS_STATUS_SUCCESS) == NSS_ACTION_RETURN)
+	return 1;
+    }
+  else
+    {
+      /* This is really only for debugging.  */
+       if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_SUCCESS)
+	 __libc_fatal ("illegal status in " __FUNCTION__);
+
+       if (nss_next_action (*ni, status) == NSS_ACTION_RETURN)
+	 return 1;
+    }
+
+  if ((*ni)->next == NULL)
+    return -1;
+
+  do
+    {
+      *ni = (*ni)->next;
+
+      *fctp = nss_lookup_function (*ni, fct_name);
+    }
+  while (*fctp == NULL
+	 && nss_next_action (*ni, NSS_STATUS_UNAVAIL) == NSS_ACTION_CONTINUE
+	 && (*ni)->next != NULL);
+
+  return *fctp != NULL ? 0 : -1;
+}
+
+
+static int
+nss_dlerror_run (void (*operate) (void))
+{
+  const char *last_errstring = NULL;
+  const char *last_object_name = NULL;
+
+  (void) _dl_catch_error (&last_errstring, &last_object_name, operate);
+
+  return last_errstring != NULL;
+}
+
+
+static void *
+nss_lookup_function (service_user *ni, const char *fct_name)
+{
+  void *result;
+
+  /* Determine whether current function is loaded.  */
+  if (nss_find_entry (&ni->known, fct_name, &result) >= 0)
+    return result;
+
+  /* If we failed to allocate the needed data structures for the
+     service return an error.  This should only happen when we are out
+     of memory.  */
+  if (ni->library == NULL)
+    return NULL;
+
+  /* We now modify global data.  Protect it.  */
+  __libc_lock_lock (lock);
+
+  if (ni->library->lib_handle == NULL)
+    {
+      /* Load the shared library.  */
+      size_t shlen = (7 + strlen (ni->library->name) + 3
+		      + sizeof (NSS_SHLIB_REVISION));
+      char shlib_name[shlen];
+
+      void do_open (void)
+	{
+	  /* The used function is found in GNU ld.so.  XXX The first
+	     argument to _dl_open used to be `_dl_loaded'.  But this
+	     does (currently) not work.  */
+	  ni->library->lib_handle = _dl_open (shlib_name, RTLD_LAZY);
+	}
+
+      /* Construct name.  */
+      __stpcpy (__stpcpy (__stpcpy (shlib_name, "libnss_"), ni->library->name),
+		".so" NSS_SHLIB_REVISION);
+
+      if (nss_dlerror_run (do_open) != 0)
+	/* Failed to load the library.  */
+	ni->library->lib_handle = (void *) -1;
+    }
+
+  if (ni->library->lib_handle == (void *) -1)
+    /* Library not found => function not found.  */
+    result = NULL;
+  else
+    {
+      /* Get the desired function.  Again,  GNU ld.so magic ahead.  */
+      size_t namlen = (5 + strlen (ni->library->name) + 1
+		       + strlen (fct_name) + 1);
+      char name[namlen];
+      struct link_map *map = ni->library->lib_handle;
+      Elf32_Addr loadbase;
+      const Elf32_Sym *ref = NULL;
+      void get_sym (void)
+	{
+	  struct link_map *scope[2] = { map, NULL };
+	  loadbase = _dl_lookup_symbol (name, &ref, scope, map->l_name, 0, 0);
+	}
+
+      __stpcpy (__stpcpy (__stpcpy (__stpcpy (name, "_nss_"),
+				    ni->library->name),
+			  "_"),
+		fct_name);
+
+      result = (nss_dlerror_run (get_sym)
+		? NULL : (void *) (loadbase + ref->st_value));
+    }
+
+  /* Remember function pointer for the usage.  */
+  nss_insert_entry (&ni->known, fct_name, result);
+
+  /* Remove the lock.  */
+  __libc_lock_unlock (lock);
+
+  return result;
+}
+
+
+static int
+known_compare (const void *p1, const void *p2)
+{
+  known_function *v1 = (known_function *) p1;
+  known_function *v2 = (known_function *) p2;
+
+  return strcmp (v1->fct_name, v2->fct_name);
+}
+
+
+static int
+nss_find_entry (struct entry **knownp, const char *key, void **valp)
+{
+  known_function looking_for = { fct_name: key };
+  struct entry **found;
+
+  found = __tfind (&looking_for, (const void **) knownp, known_compare);
+
+  if (found == NULL)
+    return -1;
+
+  *valp = ((known_function *) (*found)->key)->fct_ptr;
+
+  return 0;
+}
+
+
+static void
+nss_insert_entry (struct entry **knownp, const char *key, void *val)
+{
+  known_function *to_insert;
+
+  to_insert = (known_function *) malloc (sizeof (known_function));
+  if (to_insert == NULL)
+    return;
+
+  to_insert->fct_name = key;
+  to_insert->fct_ptr = val;
+
+  __tsearch (to_insert, (void **) knownp, known_compare);
+}
+
+
+static name_database *
+nss_parse_file (const char *fname)
+{
+  FILE *fp;
+  name_database *result;
+  name_database_entry *last;
+  char *line;
+  size_t len;
+
+  /* Open the configuration file.  */
+  fp = fopen (fname, "r");
+  if (fp == NULL)
+    return NULL;
+
+  result = (name_database *) malloc (sizeof (name_database));
+  if (result == NULL)
+    return NULL;
+
+  result->entry = NULL;
+  result->library = NULL;
+  last = NULL;
+  line = NULL;
+  len = 0;
+  do
+    {
+      name_database_entry *this;
+      ssize_t n;
+      char *cp;
+
+      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.  */
+      cp = strchr (line, '#');
+      if (cp != NULL)
+	*cp = '\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 (fp));
+
+  /* Free the buffer.  */
+  free (line);
+  /* Close configuration file.  */
+  fclose (fp);
+
+  /* Now create for each service we could use an entry in LIBRARY list.  */
+  for (last = result->entry; last != NULL; last = last->next)
+    {
+      service_user *runp;
+
+      for (runp = last->service; runp != NULL; runp = runp->next)
+	runp->library = nss_new_service (result, runp->name);
+    }
+
+  return result;
+}
+
+
+static name_database_entry *
+nss_getline (char *line)
+{
+  const char *name;
+  name_database_entry *result;
+  service_user *last;
+
+  /* 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';
+
+  result = (name_database_entry *) malloc (sizeof (name_database_entry));
+  if (result == NULL)
+    return NULL;
+
+  result->name = strdup (name);
+  if (result->name == NULL)
+    {
+      free (result);
+      return NULL;
+    }
+  result->service = NULL;
+  result->next = NULL;
+  last = NULL;
+
+  /* Read the source names: `<source> ( "[" <status> "=" <action> "]" )*'.  */
+  while (1)
+    {
+      service_user *new_service;
+      size_t n;
+
+      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));
+      if (new_service == NULL)
+	return result;
+
+      /* Test whether the source name is one of the aliases.  */
+      for (n = 0; n < sizeof (service_alias) / sizeof (service_alias[0]); ++n)
+	if (strncmp (service_alias[n].alias, name, line - name) == 0
+	    && service_alias[n].alias[line - name] == '\0')
+	  break;
+
+      if (n < sizeof (service_alias) / sizeof (service_alias[0]))
+	new_service->name = service_alias[n].value;
+      else
+	{
+	  char *source = (char *) malloc (line - name + 1);
+	  if (source == NULL)
+	    {
+	      free (new_service);
+	      return result;
+	    }
+	  memcpy (source, name, line - name);
+	  source[line - name] = '\0';
+
+	  new_service->name = source;
+	}
+
+      /* 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->library = NULL;
+      new_service->known = NULL;
+      new_service->next = NULL;
+
+      while (isspace (line[0]))
+	++line;
+
+      if (line[0] == '[')
+	{
+	  int status;
+
+	  /* Read criterions.  */
+	  do
+	    ++line;
+	  while (line[0] != '\0' && isspace (line[0]));
+
+	  do
+	    {
+	      /* 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
+		    return result;
+		}
+	      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
+		    return result;
+		}
+	      else
+		return result;
+
+	      while (isspace (line[0]))
+		++line;
+	      if (line[0] != '=')
+		return result;
+	      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)
+		new_service->actions[2 + status] = NSS_ACTION_RETURN;
+	      else if (line - name == 8
+		       && strncasecmp (name, "CONTINUE", 8) == 0)
+		new_service->actions[2 + status] = NSS_ACTION_CONTINUE;
+	      else
+		return result;
+
+	      /* Match white spaces.  */
+	      while (isspace (line[0]))
+		++line;
+	    }
+	  while (line[0] != ']');
+
+	  /* Skip the ']'.  */
+	  ++line;
+	}
+
+      if (last == NULL)
+	result->service = new_service;
+      else
+	last->next = new_service;
+      last = new_service;
+    }
+  /* NOTREACHED */
+  return NULL;
+}
+
+
+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;
+}