7fe2903c23
This adds some paranoia code that moves some of the fds we allocate for longer periods of times to fds > 2 if they are allocated below this boundary. This is a paranoid safety thing, in order to avoid that external code might end up erroneously use our fds under the assumption they were valid stdin/stdout/stderr. Think: some app closes stdin/stdout/stderr and then invokes 'fprintf(stderr, …' which causes writes on our fds. This both adds the helper to do the moving as well as ports over a number of users to this new logic. Since we don't want to litter all our code with invocations of this I tried to strictly focus on fds we keep open for long periods of times only and only in code that is frequently loaded into foreign programs (under the assumptions that in our own codebase we are smart enough to always keep stdin/stdout/stderr allocated to avoid this pitfall). Specifically this means all code used by NSS and our sd-xyz API: 1. our logging APIs 2. sd-event 3. sd-bus 4. sd-resolve 5. sd-netlink This changed was inspired by this: https://github.com/systemd/systemd/issues/8075#issuecomment-363689755 This shows that apparently IRL there are programs that do close stdin/stdout/stderr, and we should accomodate for that. Note that this won't fix any bugs, this just makes sure that buggy programs are less likely to interfere with out own code.
96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
|
|
#pragma once
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2010 Lennart Poettering
|
|
|
|
systemd 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.
|
|
|
|
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <dirent.h>
|
|
#include <stdbool.h>
|
|
#include <stdio.h>
|
|
#include <sys/socket.h>
|
|
|
|
#include "macro.h"
|
|
|
|
/* Make sure we can distinguish fd 0 and NULL */
|
|
#define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
|
|
#define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
|
|
|
|
int close_nointr(int fd);
|
|
int safe_close(int fd);
|
|
void safe_close_pair(int p[]);
|
|
|
|
void close_many(const int fds[], unsigned n_fd);
|
|
|
|
int fclose_nointr(FILE *f);
|
|
FILE* safe_fclose(FILE *f);
|
|
DIR* safe_closedir(DIR *f);
|
|
|
|
static inline void closep(int *fd) {
|
|
safe_close(*fd);
|
|
}
|
|
|
|
static inline void close_pairp(int (*p)[2]) {
|
|
safe_close_pair(*p);
|
|
}
|
|
|
|
static inline void fclosep(FILE **f) {
|
|
safe_fclose(*f);
|
|
}
|
|
|
|
DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, pclose);
|
|
DEFINE_TRIVIAL_CLEANUP_FUNC(DIR*, closedir);
|
|
|
|
#define _cleanup_close_ _cleanup_(closep)
|
|
#define _cleanup_fclose_ _cleanup_(fclosep)
|
|
#define _cleanup_pclose_ _cleanup_(pclosep)
|
|
#define _cleanup_closedir_ _cleanup_(closedirp)
|
|
#define _cleanup_close_pair_ _cleanup_(close_pairp)
|
|
|
|
int fd_nonblock(int fd, bool nonblock);
|
|
int fd_cloexec(int fd, bool cloexec);
|
|
void stdio_unset_cloexec(void);
|
|
|
|
int close_all_fds(const int except[], unsigned n_except);
|
|
|
|
int same_fd(int a, int b);
|
|
|
|
void cmsg_close_all(struct msghdr *mh);
|
|
|
|
bool fdname_is_valid(const char *s);
|
|
|
|
int fd_get_path(int fd, char **ret);
|
|
|
|
int move_fd(int from, int to, int cloexec);
|
|
|
|
enum {
|
|
ACQUIRE_NO_DEV_NULL = 1 << 0,
|
|
ACQUIRE_NO_MEMFD = 1 << 1,
|
|
ACQUIRE_NO_PIPE = 1 << 2,
|
|
ACQUIRE_NO_TMPFILE = 1 << 3,
|
|
ACQUIRE_NO_REGULAR = 1 << 4,
|
|
};
|
|
|
|
int acquire_data_fd(const void *data, size_t size, unsigned flags);
|
|
|
|
/* Hint: ENETUNREACH happens if we try to connect to "non-existing" special IP addresses, such as ::5 */
|
|
#define ERRNO_IS_DISCONNECT(r) \
|
|
IN_SET(r, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE, ENETUNREACH)
|
|
|
|
int fd_move_above_stdio(int fd);
|