aa11e28bf2
Quite often we need to set up a number of fds as stdin/stdout/stderr of a process we are about to start. Add a generic implementation for a routine doing that that takes care to do so properly: 1. Can handle the case where stdin/stdout/stderr where previously closed, and the fds to set as stdin/stdout/stderr hence likely in the 0..2 range. handling this properly is nasty, since we need to first move the fds out of this range in order to later move them back in, to make things fully robust. 2. Can optionally open /dev/null in case for one or more of the fds, in a smart way, sharing the open file if possible between multiple of the fds. 3. Guarantees that O_CLOEXEC is not set on the three fds, even if the fds already were in the 0..2 range and hence possibly weren't moved.
105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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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 License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <dirent.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <sys/socket.h>
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#include "macro.h"
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/* Make sure we can distinguish fd 0 and NULL */
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#define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
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#define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
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int close_nointr(int fd);
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int safe_close(int fd);
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void safe_close_pair(int p[]);
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static inline int safe_close_above_stdio(int fd) {
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if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
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return -1;
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return safe_close(fd);
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}
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void close_many(const int fds[], unsigned n_fd);
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int fclose_nointr(FILE *f);
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FILE* safe_fclose(FILE *f);
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DIR* safe_closedir(DIR *f);
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static inline void closep(int *fd) {
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safe_close(*fd);
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}
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static inline void close_pairp(int (*p)[2]) {
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safe_close_pair(*p);
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}
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static inline void fclosep(FILE **f) {
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safe_fclose(*f);
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}
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DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, pclose);
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DEFINE_TRIVIAL_CLEANUP_FUNC(DIR*, closedir);
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#define _cleanup_close_ _cleanup_(closep)
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#define _cleanup_fclose_ _cleanup_(fclosep)
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#define _cleanup_pclose_ _cleanup_(pclosep)
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#define _cleanup_closedir_ _cleanup_(closedirp)
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#define _cleanup_close_pair_ _cleanup_(close_pairp)
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int fd_nonblock(int fd, bool nonblock);
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int fd_cloexec(int fd, bool cloexec);
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void stdio_unset_cloexec(void);
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int close_all_fds(const int except[], unsigned n_except);
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int same_fd(int a, int b);
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void cmsg_close_all(struct msghdr *mh);
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bool fdname_is_valid(const char *s);
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int fd_get_path(int fd, char **ret);
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int move_fd(int from, int to, int cloexec);
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enum {
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ACQUIRE_NO_DEV_NULL = 1 << 0,
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ACQUIRE_NO_MEMFD = 1 << 1,
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ACQUIRE_NO_PIPE = 1 << 2,
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ACQUIRE_NO_TMPFILE = 1 << 3,
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ACQUIRE_NO_REGULAR = 1 << 4,
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};
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int acquire_data_fd(const void *data, size_t size, unsigned flags);
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/* Hint: ENETUNREACH happens if we try to connect to "non-existing" special IP addresses, such as ::5 */
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#define ERRNO_IS_DISCONNECT(r) \
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IN_SET(r, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE, ENETUNREACH)
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int fd_move_above_stdio(int fd);
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int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
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