/* Copyright (C) 2007-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2007.
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 <errno.h>
#include <string.h>
#include <not-cancel.h>
#include <_itoa.h>
#include <stdint.h>
#include "nscd-client.h"
#include "nscd_proto.h"
int __nss_not_use_nscd_services;
static int nscd_getserv_r (const char *crit, size_t critlen, const char *proto,
request_type type, struct servent *resultbuf,
char *buf, size_t buflen, struct servent **result);
int
__nscd_getservbyname_r (const char *name, const char *proto,
struct servent *result_buf, char *buf, size_t buflen,
struct servent **result)
{
return nscd_getserv_r (name, strlen (name), proto, GETSERVBYNAME, result_buf,
buf, buflen, result);
}
int
__nscd_getservbyport_r (int port, const char *proto,
struct servent *result_buf, char *buf, size_t buflen,
struct servent **result)
{
char portstr[3 * sizeof (int) + 2];
portstr[sizeof (portstr) - 1] = '\0';
char *cp = _itoa_word (port, portstr + sizeof (portstr) - 1, 10, 0);
return nscd_getserv_r (cp, portstr + sizeof (portstr) - 1 - cp, proto,
GETSERVBYPORT, result_buf, buf, buflen, result);
}
libc_locked_map_ptr (, __serv_map_handle) attribute_hidden;
/* Note that we only free the structure if necessary. The memory
mapping is not removed since it is not visible to the malloc
handling. */
libc_freeres_fn (serv_map_free)
{
if (__serv_map_handle.mapped != NO_MAPPING)
{
void *p = __serv_map_handle.mapped;
__serv_map_handle.mapped = NO_MAPPING;
free (p);
}
}
static int
nscd_getserv_r (const char *crit, size_t critlen, const char *proto,
request_type type, struct servent *resultbuf,
char *buf, size_t buflen, struct servent **result)
{
int gc_cycle;
int nretries = 0;
size_t alloca_used = 0;
/* If the mapping is available, try to search there instead of
communicating with the nscd. */
struct mapped_database *mapped;
mapped = __nscd_get_map_ref (GETFDSERV, "services", &__serv_map_handle,
&gc_cycle);
size_t protolen = proto == NULL ? 0 : strlen (proto);
size_t keylen = critlen + 1 + protolen + 1;
int alloca_key = __libc_use_alloca (keylen);
char *key;
if (alloca_key)
key = alloca_account (keylen, alloca_used);
else
{
key = malloc (keylen);
if (key == NULL)
return -1;
}
memcpy (__mempcpy (__mempcpy (key, crit, critlen),
"/", 1), proto ?: "", protolen + 1);
retry:;
const char *s_name = NULL;
const char *s_proto = NULL;
int alloca_aliases_len = 0;
const uint32_t *aliases_len = NULL;
const char *aliases_list = NULL;
int retval = -1;
const char *recend = (const char *) ~UINTMAX_C (0);
int sock = -1;
serv_response_header serv_resp;
if (mapped != NO_MAPPING)
{
struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
sizeof serv_resp);
if (found != NULL)
{
s_name = (char *) (&found->data[0].servdata + 1);
serv_resp = found->data[0].servdata;
s_proto = s_name + serv_resp.s_name_len;
alloca_aliases_len = 1;
aliases_len = (uint32_t *) (s_proto + serv_resp.s_proto_len);
aliases_list = ((char *) aliases_len
+ serv_resp.s_aliases_cnt * sizeof (uint32_t));
recend = (const char *) found->data + found->recsize;
/* Now check if we can trust serv_resp fields. If GC is
in progress, it can contain anything. */
if (mapped->head->gc_cycle != gc_cycle)
{
retval = -2;
goto out;
}
if (__builtin_expect ((const char *) aliases_len
+ serv_resp.s_aliases_cnt * sizeof (uint32_t)
> recend, 0))
goto out;
#if !_STRING_ARCH_unaligned
/* The aliases_len array in the mapped database might very
well be unaligned. We will access it word-wise so on
platforms which do not tolerate unaligned accesses we
need to make an aligned copy. */
if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1))
!= 0)
{
uint32_t *tmp;
alloca_aliases_len
= __libc_use_alloca (alloca_used
+ (serv_resp.s_aliases_cnt
* sizeof (uint32_t)));
if (alloca_aliases_len)
tmp = alloca_account (serv_resp.s_aliases_cnt
* sizeof (uint32_t),
alloca_used);
else
{
tmp = malloc (serv_resp.s_aliases_cnt * sizeof (uint32_t));
if (tmp == NULL)
{
retval = ENOMEM;
goto out;
}
}
aliases_len = memcpy (tmp, aliases_len,
serv_resp.s_aliases_cnt
* sizeof (uint32_t));
}
#endif
}
}
if (s_name == NULL)
{
sock = __nscd_open_socket (key, keylen, type, &serv_resp,
sizeof (serv_resp));
if (sock == -1)
{
__nss_not_use_nscd_services = 1;
goto out;
}
}
/* No value found so far. */
*result = NULL;
if (__glibc_unlikely (serv_resp.found == -1))
{
/* The daemon does not cache this database. */
__nss_not_use_nscd_services = 1;
goto out_close;
}
if (serv_resp.found == 1)
{
char *cp = buf;
uintptr_t align1;
uintptr_t align2;
size_t total_len;
ssize_t cnt;
int n;
/* A first check whether the buffer is sufficiently large is possible. */
/* Now allocate the buffer the array for the group members. We must
align the pointer and the base of the h_addr_list pointers. */
align1 = ((__alignof__ (char *) - (cp - ((char *) 0)))
& (__alignof__ (char *) - 1));
align2 = ((__alignof__ (char *) - ((cp + align1 + serv_resp.s_name_len
+ serv_resp.s_proto_len)
- ((char *) 0)))
& (__alignof__ (char *) - 1));
if (buflen < (align1 + serv_resp.s_name_len + serv_resp.s_proto_len
+ align2
+ (serv_resp.s_aliases_cnt + 1) * sizeof (char *)))
{
no_room:
__set_errno (ERANGE);
retval = ERANGE;
goto out_close;
}
cp += align1;
/* Prepare the result as far as we can. */
resultbuf->s_aliases = (char **) cp;
cp += (serv_resp.s_aliases_cnt + 1) * sizeof (char *);
resultbuf->s_name = cp;
cp += serv_resp.s_name_len;
resultbuf->s_proto = cp;
cp += serv_resp.s_proto_len + align2;
resultbuf->s_port = serv_resp.s_port;
if (s_name == NULL)
{
struct iovec vec[2];
vec[0].iov_base = resultbuf->s_name;
vec[0].iov_len = serv_resp.s_name_len + serv_resp.s_proto_len;
total_len = vec[0].iov_len;
n = 1;
if (serv_resp.s_aliases_cnt > 0)
{
assert (alloca_aliases_len == 0);
alloca_aliases_len
= __libc_use_alloca (alloca_used
+ (serv_resp.s_aliases_cnt
* sizeof (uint32_t)));
if (alloca_aliases_len)
aliases_len = alloca_account (serv_resp.s_aliases_cnt
* sizeof (uint32_t),
alloca_used);
else
{
aliases_len = malloc (serv_resp.s_aliases_cnt
* sizeof (uint32_t));
if (aliases_len == NULL)
{
retval = ENOMEM;
goto out_close;
}
}
vec[n].iov_base = (void *) aliases_len;
vec[n].iov_len = serv_resp.s_aliases_cnt * sizeof (uint32_t);
total_len += serv_resp.s_aliases_cnt * sizeof (uint32_t);
++n;
}
if ((size_t) __readvall (sock, vec, n) != total_len)
goto out_close;
}
else
memcpy (resultbuf->s_name, s_name,
serv_resp.s_name_len + serv_resp.s_proto_len);
/* Now we also can read the aliases. */
total_len = 0;
for (cnt = 0; cnt < serv_resp.s_aliases_cnt; ++cnt)
{
resultbuf->s_aliases[cnt] = cp;
cp += aliases_len[cnt];
total_len += aliases_len[cnt];
}
resultbuf->s_aliases[cnt] = NULL;
if (__builtin_expect ((const char *) aliases_list + total_len > recend,
0))
{
/* aliases_len array might contain garbage during nscd GC cycle,
retry rather than fail in that case. */
if (aliases_list != NULL && mapped->head->gc_cycle != gc_cycle)
retval = -2;
goto out_close;
}
/* See whether this would exceed the buffer capacity. */
if (__glibc_unlikely (cp > buf + buflen))
{
/* aliases_len array might contain garbage during nscd GC cycle,
retry rather than fail in that case. */
if (aliases_list != NULL && mapped->head->gc_cycle != gc_cycle)
{
retval = -2;
goto out_close;
}
goto no_room;
}
/* And finally read the aliases. */
if (aliases_list == NULL)
{
if (total_len == 0
|| ((size_t) __readall (sock, resultbuf->s_aliases[0], total_len)
== total_len))
{
retval = 0;
*result = resultbuf;
}
}
else
{
memcpy (resultbuf->s_aliases[0], aliases_list, total_len);
/* Try to detect corrupt databases. */
if (resultbuf->s_name[serv_resp.s_name_len - 1] != '\0'
|| resultbuf->s_proto[serv_resp.s_proto_len - 1] != '\0'
|| ({for (cnt = 0; cnt < serv_resp.s_aliases_cnt; ++cnt)
if (resultbuf->s_aliases[cnt][aliases_len[cnt] - 1]
!= '\0')
break;
cnt < serv_resp.s_aliases_cnt; }))
{
/* We cannot use the database. */
if (mapped->head->gc_cycle != gc_cycle)
retval = -2;
goto out_close;
}
retval = 0;
*result = resultbuf;
}
}
else
{
/* Set errno to 0 to indicate no error, just no found record. */
__set_errno (0);
/* Even though we have not found anything, the result is zero. */
retval = 0;
}
out_close:
if (sock != -1)
__close_nocancel_nostatus (sock);
out:
if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
{
/* When we come here this means there has been a GC cycle while we
were looking for the data. This means the data might have been
inconsistent. Retry if possible. */
if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
{
/* nscd is just running gc now. Disable using the mapping. */
if (atomic_decrement_val (&mapped->counter) == 0)
__nscd_unmap (mapped);
mapped = NO_MAPPING;
}
if (retval != -1)
{
if (!alloca_aliases_len)
free ((void *) aliases_len);
goto retry;
}
}
if (!alloca_aliases_len)
free ((void *) aliases_len);
if (!alloca_key)
free (key);
return retval;
}