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88677348b4
They are both used by __libc_freeres to free all library malloc allocated resources to help tooling like mtrace or valgrind with memory leak tracking. The current scheme uses assembly markers and linker script entries to consolidate the free routine function pointers in the RELRO segment and to be freed buffers in BSS. This patch changes it to use specific free functions for libc_freeres_ptrs buffers and call the function pointer array directly with call_function_static_weak. It allows the removal of both the internal macros and the linker script sections. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
329 lines
9.1 KiB
C
329 lines
9.1 KiB
C
/* Copyright (C) 1998-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <alloca.h>
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#include <assert.h>
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#include <errno.h>
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#include <grp.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/socket.h>
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#include <sys/uio.h>
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#include <sys/un.h>
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#include <not-cancel.h>
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#include <_itoa.h>
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#include <scratch_buffer.h>
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#include "nscd-client.h"
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#include "nscd_proto.h"
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int __nss_not_use_nscd_group;
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static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
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struct group *resultbuf, char *buffer,
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size_t buflen, struct group **result);
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int
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__nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
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size_t buflen, struct group **result)
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{
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return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
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buffer, buflen, result);
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}
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int
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__nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
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size_t buflen, struct group **result)
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{
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char buf[3 * sizeof (gid_t)];
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buf[sizeof (buf) - 1] = '\0';
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char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
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return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
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buffer, buflen, result);
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}
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libc_locked_map_ptr (,__gr_map_handle) attribute_hidden;
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/* Note that we only free the structure if necessary. The memory
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mapping is not removed since it is not visible to the malloc
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handling. */
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void
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__nscd_gr_map_freemem (void)
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{
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if (__gr_map_handle.mapped != NO_MAPPING)
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{
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void *p = __gr_map_handle.mapped;
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__gr_map_handle.mapped = NO_MAPPING;
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free (p);
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}
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}
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static int
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nscd_getgr_r (const char *key, size_t keylen, request_type type,
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struct group *resultbuf, char *buffer, size_t buflen,
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struct group **result)
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{
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int gc_cycle;
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int nretries = 0;
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const uint32_t *len = NULL;
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struct scratch_buffer lenbuf;
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scratch_buffer_init (&lenbuf);
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/* If the mapping is available, try to search there instead of
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communicating with the nscd. */
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struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
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&__gr_map_handle,
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&gc_cycle);
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retry:;
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const char *gr_name = NULL;
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size_t gr_name_len = 0;
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int retval = -1;
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const char *recend = (const char *) ~UINTMAX_C (0);
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gr_response_header gr_resp;
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if (mapped != NO_MAPPING)
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{
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struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
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sizeof gr_resp);
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if (found != NULL)
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{
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len = (const uint32_t *) (&found->data[0].grdata + 1);
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gr_resp = found->data[0].grdata;
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gr_name = ((const char *) len
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+ gr_resp.gr_mem_cnt * sizeof (uint32_t));
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gr_name_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
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recend = (const char *) found->data + found->recsize;
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/* Now check if we can trust gr_resp fields. If GC is
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in progress, it can contain anything. */
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if (mapped->head->gc_cycle != gc_cycle)
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{
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retval = -2;
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goto out;
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}
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/* The alignment is always sufficient, unless GC is in progress. */
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assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
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}
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}
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int sock = -1;
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if (gr_name == NULL)
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{
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sock = __nscd_open_socket (key, keylen, type, &gr_resp,
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sizeof (gr_resp));
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if (sock == -1)
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{
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__nss_not_use_nscd_group = 1;
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goto out;
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}
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}
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/* No value found so far. */
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*result = NULL;
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if (__glibc_unlikely (gr_resp.found == -1))
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{
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/* The daemon does not cache this database. */
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__nss_not_use_nscd_group = 1;
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goto out_close;
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}
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if (gr_resp.found == 1)
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{
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struct iovec vec[2];
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char *p = buffer;
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size_t total_len;
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uintptr_t align;
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nscd_ssize_t cnt;
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/* Now allocate the buffer the array for the group members. We must
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align the pointer. */
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align = ((__alignof__ (char *) - ((uintptr_t) p))
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& (__alignof__ (char *) - 1));
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total_len = (align + (1 + gr_resp.gr_mem_cnt) * sizeof (char *)
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+ gr_resp.gr_name_len + gr_resp.gr_passwd_len);
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if (__glibc_unlikely (buflen < total_len))
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{
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no_room:
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__set_errno (ERANGE);
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retval = ERANGE;
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goto out_close;
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}
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buflen -= total_len;
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p += align;
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resultbuf->gr_mem = (char **) p;
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p += (1 + gr_resp.gr_mem_cnt) * sizeof (char *);
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/* Set pointers for strings. */
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resultbuf->gr_name = p;
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p += gr_resp.gr_name_len;
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resultbuf->gr_passwd = p;
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p += gr_resp.gr_passwd_len;
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/* Fill in what we know now. */
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resultbuf->gr_gid = gr_resp.gr_gid;
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/* Read the length information, group name, and password. */
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if (gr_name == NULL)
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{
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/* Handle a simple, usual case: no group members. */
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if (__glibc_likely (gr_resp.gr_mem_cnt == 0))
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{
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size_t n = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
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if (__builtin_expect (__readall (sock, resultbuf->gr_name, n)
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!= (ssize_t) n, 0))
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goto out_close;
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}
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else
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{
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/* Allocate array to store lengths. */
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if (!scratch_buffer_set_array_size
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(&lenbuf, gr_resp.gr_mem_cnt, sizeof (uint32_t)))
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goto out_close;
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len = lenbuf.data;
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vec[0].iov_base = (void *) len;
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vec[0].iov_len = gr_resp.gr_mem_cnt * sizeof (uint32_t);
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vec[1].iov_base = resultbuf->gr_name;
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vec[1].iov_len = gr_resp.gr_name_len + gr_resp.gr_passwd_len;
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total_len = vec[0].iov_len + vec[1].iov_len;
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/* Get this data. */
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size_t n = __readvall (sock, vec, 2);
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if (__glibc_unlikely (n != total_len))
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goto out_close;
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}
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}
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else
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/* We already have the data. Just copy the group name and
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password. */
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memcpy (resultbuf->gr_name, gr_name,
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gr_resp.gr_name_len + gr_resp.gr_passwd_len);
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/* Clear the terminating entry. */
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resultbuf->gr_mem[gr_resp.gr_mem_cnt] = NULL;
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/* Prepare reading the group members. */
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total_len = 0;
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for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
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{
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resultbuf->gr_mem[cnt] = p;
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total_len += len[cnt];
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p += len[cnt];
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}
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if (__glibc_unlikely (gr_name + gr_name_len + total_len > recend))
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{
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/* len array might contain garbage during nscd GC cycle,
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retry rather than fail in that case. */
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if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
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retval = -2;
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goto out_close;
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}
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if (__glibc_unlikely (total_len > buflen))
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{
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/* len array might contain garbage during nscd GC cycle,
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retry rather than fail in that case. */
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if (gr_name != NULL && mapped->head->gc_cycle != gc_cycle)
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{
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retval = -2;
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goto out_close;
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}
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else
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goto no_room;
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}
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retval = 0;
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/* If there are no group members TOTAL_LEN is zero. */
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if (gr_name == NULL)
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{
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if (total_len > 0
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&& __builtin_expect (__readall (sock, resultbuf->gr_mem[0],
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total_len) != total_len, 0))
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{
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/* The `errno' to some value != ERANGE. */
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__set_errno (ENOENT);
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retval = ENOENT;
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}
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else
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*result = resultbuf;
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}
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else
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{
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/* Copy the group member names. */
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memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
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/* Try to detect corrupt databases. */
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if (resultbuf->gr_name[gr_name_len - 1] != '\0'
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|| resultbuf->gr_passwd[gr_resp.gr_passwd_len - 1] != '\0'
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|| ({for (cnt = 0; cnt < gr_resp.gr_mem_cnt; ++cnt)
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if (resultbuf->gr_mem[cnt][len[cnt] - 1] != '\0')
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break;
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cnt < gr_resp.gr_mem_cnt; }))
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{
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/* We cannot use the database. */
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retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
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goto out_close;
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}
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*result = resultbuf;
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}
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}
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else
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{
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/* Set errno to 0 to indicate no error, just no found record. */
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__set_errno (0);
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/* Even though we have not found anything, the result is zero. */
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retval = 0;
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}
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out_close:
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if (sock != -1)
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__close_nocancel_nostatus (sock);
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out:
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if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
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{
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/* When we come here this means there has been a GC cycle while we
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were looking for the data. This means the data might have been
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inconsistent. Retry if possible. */
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if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
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{
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/* nscd is just running gc now. Disable using the mapping. */
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if (atomic_fetch_add_relaxed (&mapped->counter, -1) == 1)
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__nscd_unmap (mapped);
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mapped = NO_MAPPING;
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}
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if (retval != -1)
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goto retry;
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}
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scratch_buffer_free (&lenbuf);
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return retval;
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}
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