src/basic/fd-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /***
   5   This file is part of systemd.
   6
   7   Copyright 2010 Lennart Poettering
   8 ***/
   9
  10 #include <dirent.h>
  11 #include <stdbool.h>
  12 #include <stdio.h>
  13 #include <sys/socket.h>
  14
  15 #include "macro.h"
  16
  17 /* Make sure we can distinguish fd 0 and NULL */
  18 #define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
  19 #define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
  20
  21 int close_nointr(int fd);
  22 int safe_close(int fd);
  23 void safe_close_pair(int p[]);
  24
  25 static inline int safe_close_above_stdio(int fd) {
  26         if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
  27                 return -1;
  28
  29         return safe_close(fd);
  30 }
  31
  32 void close_many(const int fds[], unsigned n_fd);
  33
  34 int fclose_nointr(FILE *f);
  35 FILE* safe_fclose(FILE *f);
  36 DIR* safe_closedir(DIR *f);
  37
  38 static inline void closep(int *fd) {
  39         safe_close(*fd);
  40 }
  41
  42 static inline void close_pairp(int (*p)[2]) {
  43         safe_close_pair(*p);
  44 }
  45
  46 static inline void fclosep(FILE **f) {
  47         safe_fclose(*f);
  48 }
  49
  50 DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, pclose);
  51 DEFINE_TRIVIAL_CLEANUP_FUNC(DIR*, closedir);
  52
  53 #define _cleanup_close_ _cleanup_(closep)
  54 #define _cleanup_fclose_ _cleanup_(fclosep)
  55 #define _cleanup_pclose_ _cleanup_(pclosep)
  56 #define _cleanup_closedir_ _cleanup_(closedirp)
  57 #define _cleanup_close_pair_ _cleanup_(close_pairp)
  58
  59 int fd_nonblock(int fd, bool nonblock);
  60 int fd_cloexec(int fd, bool cloexec);
  61
  62 int close_all_fds(const int except[], unsigned n_except);
  63
  64 int same_fd(int a, int b);
  65
  66 void cmsg_close_all(struct msghdr *mh);
  67
  68 bool fdname_is_valid(const char *s);
  69
  70 int fd_get_path(int fd, char **ret);
  71
  72 int move_fd(int from, int to, int cloexec);
  73
  74 enum {
  75         ACQUIRE_NO_DEV_NULL = 1 << 0,
  76         ACQUIRE_NO_MEMFD    = 1 << 1,
  77         ACQUIRE_NO_PIPE     = 1 << 2,
  78         ACQUIRE_NO_TMPFILE  = 1 << 3,
  79         ACQUIRE_NO_REGULAR  = 1 << 4,
  80 };
  81
  82 int acquire_data_fd(const void *data, size_t size, unsigned flags);
  83
  84 /* Hint: ENETUNREACH happens if we try to connect to "non-existing" special IP addresses, such as ::5 */
  85 #define ERRNO_IS_DISCONNECT(r) \
  86         IN_SET(r, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE, ENETUNREACH)
  87
  88 /* Resource exhaustion, could be our fault or general system trouble */
  89 #define ERRNO_IS_RESOURCE(r) \
  90         IN_SET(r, ENOMEM, EMFILE, ENFILE)
  91
  92 int fd_move_above_stdio(int fd);
  93
  94 int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
  95
  96 static inline int make_null_stdio(void) {
  97         return rearrange_stdio(-1, -1, -1);
  98 }
  99
 100 /* Like TAKE_PTR() but for file descriptors, resetting them to -1 */
 101 #define TAKE_FD(fd)                             \
 102         ({                                      \
 103                 int _fd_ = (fd);                \
 104                 (fd) = -1;                      \
 105                 _fd_;                           \
 106         })
 107
 108 int fd_reopen(int fd, int flags);