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-rw-r--r--nss/nsswitch.c588
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;
+}
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