Systemd/src/basic/fd-util.h
Lennart Poettering da6053d0a7 tree-wide: be more careful with the type of array sizes
Previously we were a bit sloppy with the index and size types of arrays,
we'd regularly use unsigned. While I don't think this ever resulted in
real issues I think we should be more careful there and follow a
stricter regime: unless there's a strong reason not to use size_t for
array sizes and indexes, size_t it should be. Any allocations we do
ultimately will use size_t anyway, and converting forth and back between
unsigned and size_t will always be a source of problems.

Note that on 32bit machines "unsigned" and "size_t" are equivalent, and
on 64bit machines our arrays shouldn't grow that large anyway, and if
they do we have a problem, however that kind of overly large allocation
we have protections for usually, but for overflows we do not have that
so much, hence let's add it.

So yeah, it's a story of the current code being already "good enough",
but I think some extra type hygiene is better.

This patch tries to be comprehensive, but it probably isn't and I missed
a few cases. But I guess we can cover that later as we notice it. Among
smaller fixes, this changes:

1. strv_length()' return type becomes size_t

2. the unit file changes array size becomes size_t

3. DNS answer and query array sizes become size_t

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=76745
2018-04-27 14:29:06 +02:00

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2.8 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
***/
#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[]);
static inline int safe_close_above_stdio(int fd) {
if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
return -1;
return safe_close(fd);
}
void close_many(const int fds[], size_t 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);
int close_all_fds(const int except[], size_t 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)
/* Resource exhaustion, could be our fault or general system trouble */
#define ERRNO_IS_RESOURCE(r) \
IN_SET(r, ENOMEM, EMFILE, ENFILE)
int fd_move_above_stdio(int fd);
int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
static inline int make_null_stdio(void) {
return rearrange_stdio(-1, -1, -1);
}
/* Like TAKE_PTR() but for file descriptors, resetting them to -1 */
#define TAKE_FD(fd) \
({ \
int _fd_ = (fd); \
(fd) = -1; \
_fd_; \
})
int fd_reopen(int fd, int flags);