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/* Copyright (C) 1998-2022 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
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <not-cancel.h>
#include <_itoa.h>
#include "nscd-client.h"
#include "nscd_proto.h"
int __nss_not_use_nscd_passwd;
static int nscd_getpw_r (const char *key, size_t keylen, request_type type,
struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result);
int
__nscd_getpwnam_r (const char *name, struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result)
{
if (name == NULL)
return -1;
return nscd_getpw_r (name, strlen (name) + 1, GETPWBYNAME, resultbuf,
buffer, buflen, result);
}
int
__nscd_getpwuid_r (uid_t uid, struct passwd *resultbuf, char *buffer,
size_t buflen, struct passwd **result)
{
char buf[3 * sizeof (uid_t)];
buf[sizeof (buf) - 1] = '\0';
char *cp = _itoa_word (uid, buf + sizeof (buf) - 1, 10, 0);
return nscd_getpw_r (cp, buf + sizeof (buf) - cp, GETPWBYUID, resultbuf,
buffer, buflen, result);
}
libc_locked_map_ptr (static, map_handle);
/* 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 (pw_map_free)
{
if (map_handle.mapped != NO_MAPPING)
{
void *p = map_handle.mapped;
map_handle.mapped = NO_MAPPING;
free (p);
}
}
static int
nscd_getpw_r (const char *key, size_t keylen, request_type type,
struct passwd *resultbuf, char *buffer, size_t buflen,
struct passwd **result)
{
int gc_cycle;
int nretries = 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 (GETFDPW, "passwd", &map_handle, &gc_cycle);
retry:;
const char *pw_name = NULL;
int retval = -1;
const char *recend = (const char *) ~UINTMAX_C (0);
pw_response_header pw_resp;
if (mapped != NO_MAPPING)
{
struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
sizeof pw_resp);
if (found != NULL)
{
pw_name = (const char *) (&found->data[0].pwdata + 1);
pw_resp = found->data[0].pwdata;
recend = (const char *) found->data + found->recsize;
/* Now check if we can trust pw_resp fields. If GC is
in progress, it can contain anything. */
if (mapped->head->gc_cycle != gc_cycle)
{
retval = -2;
goto out;
}
}
}
int sock = -1;
if (pw_name == NULL)
{
sock = __nscd_open_socket (key, keylen, type, &pw_resp,
sizeof (pw_resp));
if (sock == -1)
{
__nss_not_use_nscd_passwd = 1;
goto out;
}
}
/* No value found so far. */
*result = NULL;
if (__glibc_unlikely (pw_resp.found == -1))
{
/* The daemon does not cache this database. */
__nss_not_use_nscd_passwd = 1;
goto out_close;
}
if (pw_resp.found == 1)
{
/* Set the information we already have. */
resultbuf->pw_uid = pw_resp.pw_uid;
resultbuf->pw_gid = pw_resp.pw_gid;
char *p = buffer;
/* get pw_name */
resultbuf->pw_name = p;
p += pw_resp.pw_name_len;
/* get pw_passwd */
resultbuf->pw_passwd = p;
p += pw_resp.pw_passwd_len;
/* get pw_gecos */
resultbuf->pw_gecos = p;
p += pw_resp.pw_gecos_len;
/* get pw_dir */
resultbuf->pw_dir = p;
p += pw_resp.pw_dir_len;
/* get pw_pshell */
resultbuf->pw_shell = p;
p += pw_resp.pw_shell_len;
ssize_t total = p - buffer;
if (__glibc_unlikely (pw_name + total > recend))
goto out_close;
if (__glibc_unlikely (buflen < total))
{
__set_errno (ERANGE);
retval = ERANGE;
goto out_close;
}
retval = 0;
if (pw_name == NULL)
{
ssize_t nbytes = __readall (sock, buffer, total);
if (__glibc_unlikely (nbytes != total))
{
/* The `errno' to some value != ERANGE. */
__set_errno (ENOENT);
retval = ENOENT;
}
else
*result = resultbuf;
}
else
{
/* Copy the various strings. */
memcpy (resultbuf->pw_name, pw_name, total);
/* Try to detect corrupt databases. */
if (resultbuf->pw_name[pw_resp.pw_name_len - 1] != '\0'
|| resultbuf->pw_passwd[pw_resp.pw_passwd_len - 1] != '\0'
|| resultbuf->pw_gecos[pw_resp.pw_gecos_len - 1] != '\0'
|| resultbuf->pw_dir[pw_resp.pw_dir_len - 1] != '\0'
|| resultbuf->pw_shell[pw_resp.pw_shell_len - 1] != '\0')
{
/* We cannot use the database. */
retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
goto out_close;
}
*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_fetch_add_relaxed (&mapped->counter, -1) == 1)
__nscd_unmap (mapped);
mapped = NO_MAPPING;
}
if (retval != -1)
goto retry;
}
return retval;
}
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