/* Copyright (C) 1996-2018 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 <assert.h>
#include <atomic.h>
#include <libc-lock.h>
#include <errno.h>
#include <netdb.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "netgroup.h"
#include "nsswitch.h"
#include <sysdep.h>
#include <nscd/nscd_proto.h>
/* Protect above variable against multiple uses at the same time. */
__libc_lock_define_initialized (static, lock)
/* The whole information for the set/get/endnetgrent functions are
kept in this structure. */
static struct __netgrent dataset;
/* Set up NIP to run through the services. Return nonzero if there are no
services (left). */
static int
setup (void **fctp, service_user **nipp)
{
/* Remember the first service_entry, it's always the same. */
static bool startp_initialized;
static service_user *startp;
int no_more;
if (!startp_initialized)
{
/* Executing this more than once at the same time must yield the
same result every time. So we need no locking. */
no_more = __nss_netgroup_lookup2 (nipp, "setnetgrent", NULL, fctp);
startp = no_more ? (service_user *) -1 : *nipp;
#ifdef PTR_MANGLE
PTR_MANGLE (startp);
#endif
atomic_write_barrier ();
startp_initialized = true;
}
else
{
service_user *nip = startp;
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (nip);
#endif
if (nip == (service_user *) -1)
/* No services at all. */
return 1;
/* Reset to the beginning of the service list. */
*nipp = nip;
/* Look up the first function. */
no_more = __nss_lookup (nipp, "setnetgrent", NULL, fctp);
}
return no_more;
}
/* Free used memory. */
static void
free_memory (struct __netgrent *data)
{
while (data->known_groups != NULL)
{
struct name_list *tmp = data->known_groups;
data->known_groups = data->known_groups->next;
free (tmp);
}
while (data->needed_groups != NULL)
{
struct name_list *tmp = data->needed_groups;
data->needed_groups = data->needed_groups->next;
free (tmp);
}
}
static void
endnetgrent_hook (struct __netgrent *datap)
{
enum nss_status (*endfct) (struct __netgrent *);
if (datap->nip == NULL || datap->nip == (service_user *) -1l)
return;
endfct = __nss_lookup_function (datap->nip, "endnetgrent");
if (endfct != NULL)
(void) (*endfct) (datap);
datap->nip = NULL;
}
static int
__internal_setnetgrent_reuse (const char *group, struct __netgrent *datap,
int *errnop)
{
union
{
enum nss_status (*f) (const char *, struct __netgrent *);
void *ptr;
} fct;
enum nss_status status = NSS_STATUS_UNAVAIL;
struct name_list *new_elem;
/* Free data from previous service. */
endnetgrent_hook (datap);
/* Cycle through all the services and run their setnetgrent functions. */
int no_more = setup (&fct.ptr, &datap->nip);
while (! no_more)
{
assert (datap->data == NULL);
/* Ignore status, we force check in `__nss_next2'. */
status = DL_CALL_FCT (*fct.f, (group, datap));
service_user *old_nip = datap->nip;
no_more = __nss_next2 (&datap->nip, "setnetgrent", NULL, &fct.ptr,
status, 0);
if (status == NSS_STATUS_SUCCESS && ! no_more)
{
enum nss_status (*endfct) (struct __netgrent *);
endfct = __nss_lookup_function (old_nip, "endnetgrent");
if (endfct != NULL)
(void) DL_CALL_FCT (*endfct, (datap));
}
}
/* Add the current group to the list of known groups. */
size_t group_len = strlen (group) + 1;
new_elem = (struct name_list *) malloc (sizeof (struct name_list)
+ group_len);
if (new_elem == NULL)
{
*errnop = errno;
status = NSS_STATUS_TRYAGAIN;
}
else
{
new_elem->next = datap->known_groups;
memcpy (new_elem->name, group, group_len);
datap->known_groups = new_elem;
}
return status == NSS_STATUS_SUCCESS;
}
int
__internal_setnetgrent (const char *group, struct __netgrent *datap)
{
/* Free list of all netgroup names from last run. */
free_memory (datap);
return __internal_setnetgrent_reuse (group, datap, &errno);
}
libc_hidden_def (__internal_setnetgrent)
static int
nscd_setnetgrent (const char *group)
{
#ifdef USE_NSCD
if (__nss_not_use_nscd_netgroup > 0
&& ++__nss_not_use_nscd_netgroup > NSS_NSCD_RETRY)
__nss_not_use_nscd_netgroup = 0;
if (!__nss_not_use_nscd_netgroup
&& !__nss_database_custom[NSS_DBSIDX_netgroup])
return __nscd_setnetgrent (group, &dataset);
#endif
return -1;
}
int
setnetgrent (const char *group)
{
int result;
__libc_lock_lock (lock);
result = nscd_setnetgrent (group);
if (result < 0)
result = __internal_setnetgrent (group, &dataset);
__libc_lock_unlock (lock);
return result;
}
void
__internal_endnetgrent (struct __netgrent *datap)
{
endnetgrent_hook (datap);
/* Now free list of all netgroup names from last run. */
free_memory (datap);
}
libc_hidden_def (__internal_endnetgrent)
void
endnetgrent (void)
{
__libc_lock_lock (lock);
__internal_endnetgrent (&dataset);
__libc_lock_unlock (lock);
}
#ifdef USE_NSCD
static const char *
get_nonempty_val (const char *in)
{
if (*in == '\0')
return NULL;
return in;
}
static enum nss_status
nscd_getnetgrent (struct __netgrent *datap, char *buffer, size_t buflen,
int *errnop)
{
if (datap->cursor >= datap->data + datap->data_size)
return NSS_STATUS_UNAVAIL;
datap->type = triple_val;
datap->val.triple.host = get_nonempty_val (datap->cursor);
datap->cursor = (char *) __rawmemchr (datap->cursor, '\0') + 1;
datap->val.triple.user = get_nonempty_val (datap->cursor);
datap->cursor = (char *) __rawmemchr (datap->cursor, '\0') + 1;
datap->val.triple.domain = get_nonempty_val (datap->cursor);
datap->cursor = (char *) __rawmemchr (datap->cursor, '\0') + 1;
return NSS_STATUS_SUCCESS;
}
#endif
int
__internal_getnetgrent_r (char **hostp, char **userp, char **domainp,
struct __netgrent *datap,
char *buffer, size_t buflen, int *errnop)
{
enum nss_status (*fct) (struct __netgrent *, char *, size_t, int *);
/* Initialize status to return if no more functions are found. */
enum nss_status status = NSS_STATUS_NOTFOUND;
/* Run through available functions, starting with the same function last
run. We will repeat each function as long as it succeeds, and then go
on to the next service action. */
int no_more = datap->nip == NULL;
if (! no_more)
{
#ifdef USE_NSCD
/* This bogus function pointer is a special marker left by
__nscd_setnetgrent to tell us to use the data it left
before considering any modules. */
if (datap->nip == (service_user *) -1l)
fct = nscd_getnetgrent;
else
#endif
{
fct = __nss_lookup_function (datap->nip, "getnetgrent_r");
no_more = fct == NULL;
}
while (! no_more)
{
status = DL_CALL_FCT (*fct, (datap, buffer, buflen, &errno));
if (status == NSS_STATUS_RETURN
/* The service returned a NOTFOUND, but there are more groups that
we need to resolve before we give up. */
|| (status == NSS_STATUS_NOTFOUND && datap->needed_groups != NULL))
{
/* This was the last one for this group. Look at next group
if available. */
int found = 0;
while (datap->needed_groups != NULL && ! found)
{
struct name_list *tmp = datap->needed_groups;
datap->needed_groups = datap->needed_groups->next;
tmp->next = datap->known_groups;
datap->known_groups = tmp;
found = __internal_setnetgrent_reuse (datap->known_groups->name,
datap, errnop);
}
if (found && datap->nip != NULL)
{
fct = __nss_lookup_function (datap->nip, "getnetgrent_r");
if (fct != NULL)
continue;
}
}
else if (status == NSS_STATUS_SUCCESS && datap->type == group_val)
{
/* The last entry was a name of another netgroup. */
struct name_list *namep;
/* Ignore if we've seen the name before. */
for (namep = datap->known_groups; namep != NULL;
namep = namep->next)
if (strcmp (datap->val.group, namep->name) == 0)
break;
if (namep == NULL)
for (namep = datap->needed_groups; namep != NULL;
namep = namep->next)
if (strcmp (datap->val.group, namep->name) == 0)
break;
if (namep != NULL)
/* Really ignore. */
continue;
size_t group_len = strlen (datap->val.group) + 1;
namep = (struct name_list *) malloc (sizeof (struct name_list)
+ group_len);
if (namep == NULL)
/* We are out of memory. */
status = NSS_STATUS_RETURN;
else
{
namep->next = datap->needed_groups;
memcpy (namep->name, datap->val.group, group_len);
datap->needed_groups = namep;
/* And get the next entry. */
continue;
}
}
break;
}
}
if (status == NSS_STATUS_SUCCESS)
{
*hostp = (char *) datap->val.triple.host;
*userp = (char *) datap->val.triple.user;
*domainp = (char *) datap->val.triple.domain;
}
return status == NSS_STATUS_SUCCESS ? 1 : 0;
}
libc_hidden_def (__internal_getnetgrent_r)
/* The real entry point. */
int
__getnetgrent_r (char **hostp, char **userp, char **domainp,
char *buffer, size_t buflen)
{
enum nss_status status;
__libc_lock_lock (lock);
status = __internal_getnetgrent_r (hostp, userp, domainp, &dataset,
buffer, buflen, &errno);
__libc_lock_unlock (lock);
return status;
}
weak_alias (__getnetgrent_r, getnetgrent_r)
/* Test whether given (host,user,domain) triple is in NETGROUP. */
int
innetgr (const char *netgroup, const char *host, const char *user,
const char *domain)
{
#ifdef USE_NSCD
if (__nss_not_use_nscd_netgroup > 0
&& ++__nss_not_use_nscd_netgroup > NSS_NSCD_RETRY)
__nss_not_use_nscd_netgroup = 0;
if (!__nss_not_use_nscd_netgroup
&& !__nss_database_custom[NSS_DBSIDX_netgroup])
{
int result = __nscd_innetgr (netgroup, host, user, domain);
if (result >= 0)
return result;
}
#endif
union
{
enum nss_status (*f) (const char *, struct __netgrent *);
void *ptr;
} setfct;
void (*endfct) (struct __netgrent *);
int (*getfct) (struct __netgrent *, char *, size_t, int *);
struct __netgrent entry;
int result = 0;
const char *current_group = netgroup;
memset (&entry, '\0', sizeof (entry));
/* Walk through the services until we found an answer or we shall
not work further. We can do some optimization here. Since all
services must provide the `setnetgrent' function we can do all
the work during one walk through the service list. */
while (1)
{
int no_more = setup (&setfct.ptr, &entry.nip);
while (! no_more)
{
assert (entry.data == NULL);
/* Open netgroup. */
enum nss_status status = DL_CALL_FCT (*setfct.f,
(current_group, &entry));
if (status == NSS_STATUS_SUCCESS
&& (getfct = __nss_lookup_function (entry.nip, "getnetgrent_r"))
!= NULL)
{
char buffer[1024];
while (DL_CALL_FCT (*getfct,
(&entry, buffer, sizeof buffer, &errno))
== NSS_STATUS_SUCCESS)
{
if (entry.type == group_val)
{
/* Make sure we haven't seen the name before. */
struct name_list *namep;
for (namep = entry.known_groups; namep != NULL;
namep = namep->next)
if (strcmp (entry.val.group, namep->name) == 0)
break;
if (namep == NULL)
for (namep = entry.needed_groups; namep != NULL;
namep = namep->next)
if (strcmp (entry.val.group, namep->name) == 0)
break;
if (namep == NULL
&& strcmp (netgroup, entry.val.group) != 0)
{
size_t group_len = strlen (entry.val.group) + 1;
namep =
(struct name_list *) malloc (sizeof (*namep)
+ group_len);
if (namep == NULL)
{
/* Out of memory, simply return. */
result = -1;
break;
}
namep->next = entry.needed_groups;
memcpy (namep->name, entry.val.group, group_len);
entry.needed_groups = namep;
}
}
else
{
if ((entry.val.triple.host == NULL || host == NULL
|| __strcasecmp (entry.val.triple.host, host) == 0)
&& (entry.val.triple.user == NULL || user == NULL
|| strcmp (entry.val.triple.user, user) == 0)
&& (entry.val.triple.domain == NULL || domain == NULL
|| __strcasecmp (entry.val.triple.domain,
domain) == 0))
{
result = 1;
break;
}
}
}
/* If we found one service which does know the given
netgroup we don't try further. */
status = NSS_STATUS_RETURN;
}
/* Free all resources of the service. */
endfct = __nss_lookup_function (entry.nip, "endnetgrent");
if (endfct != NULL)
DL_CALL_FCT (*endfct, (&entry));
if (result != 0)
break;
/* Look for the next service. */
no_more = __nss_next2 (&entry.nip, "setnetgrent", NULL,
&setfct.ptr, status, 0);
}
if (result == 0 && entry.needed_groups != NULL)
{
struct name_list *tmp = entry.needed_groups;
entry.needed_groups = tmp->next;
tmp->next = entry.known_groups;
entry.known_groups = tmp;
current_group = tmp->name;
continue;
}
/* No way out. */
break;
}
/* Free the memory. */
free_memory (&entry);
return result == 1;
}
libc_hidden_def (innetgr)