src/basic/fd-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <dirent.h>
   5 #include <stdbool.h>
   6 #include <stdio.h>
   7 #include <sys/socket.h>
   8
   9 #include "macro.h"
  10
  11 /* maximum length of fdname */
  12 #define FDNAME_MAX 255
  13
  14 /* Make sure we can distinguish fd 0 and NULL */
  15 #define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
  16 #define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
  17
  18 int close_nointr(int fd);
  19 int safe_close(int fd);
  20 void safe_close_pair(int p[static 2]);
  21
  22 static inline int safe_close_above_stdio(int fd) {
  23         if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
  24                 return -1;
  25
  26         return safe_close(fd);
  27 }
  28
  29 void close_many(const int fds[], size_t n_fd);
  30
  31 int fclose_nointr(FILE *f);
  32 FILE* safe_fclose(FILE *f);
  33 DIR* safe_closedir(DIR *f);
  34
  35 static inline void closep(int *fd) {
  36         safe_close(*fd);
  37 }
  38
  39 static inline void close_pairp(int (*p)[2]) {
  40         safe_close_pair(*p);
  41 }
  42
  43 static inline void fclosep(FILE **f) {
  44         safe_fclose(*f);
  45 }
  46
  47 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(FILE*, pclose, NULL);
  48 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(DIR*, closedir, NULL);
  49
  50 #define _cleanup_close_ _cleanup_(closep)
  51 #define _cleanup_fclose_ _cleanup_(fclosep)
  52 #define _cleanup_pclose_ _cleanup_(pclosep)
  53 #define _cleanup_closedir_ _cleanup_(closedirp)
  54 #define _cleanup_close_pair_ _cleanup_(close_pairp)
  55
  56 int fd_nonblock(int fd, bool nonblock);
  57 int fd_cloexec(int fd, bool cloexec);
  58
  59 int close_all_fds(const int except[], size_t n_except);
  60
  61 int same_fd(int a, int b);
  62
  63 void cmsg_close_all(struct msghdr *mh);
  64
  65 bool fdname_is_valid(const char *s);
  66
  67 int fd_get_path(int fd, char **ret);
  68
  69 int move_fd(int from, int to, int cloexec);
  70
  71 enum {
  72         ACQUIRE_NO_DEV_NULL = 1 << 0,
  73         ACQUIRE_NO_MEMFD    = 1 << 1,
  74         ACQUIRE_NO_PIPE     = 1 << 2,
  75         ACQUIRE_NO_TMPFILE  = 1 << 3,
  76         ACQUIRE_NO_REGULAR  = 1 << 4,
  77 };
  78
  79 int acquire_data_fd(const void *data, size_t size, unsigned flags);
  80
  81 int fd_duplicate_data_fd(int fd);
  82
  83 int fd_move_above_stdio(int fd);
  84
  85 int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
  86
  87 static inline int make_null_stdio(void) {
  88         return rearrange_stdio(-1, -1, -1);
  89 }
  90
  91 /* Like TAKE_PTR() but for file descriptors, resetting them to -1 */
  92 #define TAKE_FD(fd)                             \
  93         ({                                      \
  94                 int _fd_ = (fd);                \
  95                 (fd) = -1;                      \
  96                 _fd_;                           \
  97         })
  98
  99 /* Like free_and_replace(), but for file descriptors */
 100 #define CLOSE_AND_REPLACE(a, b)                 \
 101         ({                                      \
 102                 int *_fdp_ = &(a);              \
 103                 safe_close(*_fdp_);             \
 104                 *_fdp_ = TAKE_FD(b);            \
 105                 0;                              \
 106         })
 107
 108
 109 int fd_reopen(int fd, int flags);
 110
 111 int read_nr_open(void);