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https://github.com/samba-team/samba.git
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55529d0f85
There is closefrom in some BSDs, but Linux ships this only as part of libbsd. Add a new implementation of it in libreplace. The one in libbsd of jessie and upstream differ and it has for example optimizations for FreeBSD, but it gets some of the array calculations slightly wrong from my point of view. If you want those, use libbsd. This replacement is optimized on Linux only looking at /proc/self/fd/, everything else would do the OPEN_MAX brute force fallback. Signed-off-by: Volker Lendecke <vl@samba.org>
139 lines
2.6 KiB
C
139 lines
2.6 KiB
C
/*
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* Unix SMB/CIFS implementation.
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* Samba utility functions
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* Copyright (C) Volker Lendecke 2016
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*
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* ** NOTE! The following LGPL license applies to the replace
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* ** library. This does NOT imply that all of Samba is released
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* ** under the LGPL
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*
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* This 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 3 of the License, or (at your option) any later version.
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*
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* This 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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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include <dirent.h>
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#include <unistd.h>
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#include <limits.h>
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static int closefrom_sysconf(int lower)
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{
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long max_files, fd;
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max_files = sysconf(_SC_OPEN_MAX);
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if (max_files == -1) {
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max_files = 65536;
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}
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for (fd=lower; fd<max_files; fd++) {
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close(fd);
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}
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return 0;
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}
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static int closefrom_procfs(int lower)
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{
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DIR *dirp;
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int dir_fd;
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struct dirent *dp;
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int *fds = NULL;
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size_t num_fds = 0;
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size_t fd_array_size = 0;
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size_t i;
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int ret = ENOMEM;
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dirp = opendir("/proc/self/fd");
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if (dirp == 0) {
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return errno;
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}
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dir_fd = dirfd(dirp);
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if (dir_fd == -1) {
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ret = errno;
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goto fail;
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}
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while ((dp = readdir(dirp)) != NULL) {
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char *endptr;
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unsigned long long fd;
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errno = 0;
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fd = strtoull(dp->d_name, &endptr, 10);
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if ((fd == 0) && (errno == EINVAL)) {
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continue;
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}
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if ((fd == ULLONG_MAX) && (errno == ERANGE)) {
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continue;
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}
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if (*endptr != '\0') {
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continue;
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}
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if (fd == dir_fd) {
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continue;
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}
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if (fd > INT_MAX) {
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continue;
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}
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if (fd < lower) {
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continue;
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}
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if (num_fds >= (fd_array_size / sizeof(int))) {
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void *tmp;
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if (fd_array_size == 0) {
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fd_array_size = 16 * sizeof(int);
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} else {
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if (fd_array_size + fd_array_size <
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fd_array_size) {
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/* overflow */
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goto fail;
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}
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fd_array_size = fd_array_size + fd_array_size;
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}
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tmp = realloc(fds, fd_array_size);
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if (tmp == NULL) {
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goto fail;
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}
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fds = tmp;
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}
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fds[num_fds++] = fd;
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}
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for (i=0; i<num_fds; i++) {
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close(fds[i]);
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}
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ret = 0;
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fail:
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closedir(dirp);
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free(fds);
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return ret;
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}
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int rep_closefrom(int lower)
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{
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int ret;
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ret = closefrom_procfs(lower);
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if (ret == 0) {
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return 0;
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}
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return closefrom_sysconf(lower);
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}
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