src/basic/fd-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 /* Make sure we can distinguish fd 0 and NULL */
  12 #define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
  13 #define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
  14
  15 int close_nointr(int fd);
  16 int safe_close(int fd);
  17 void safe_close_pair(int p[static 2]);
  18
  19 static inline int safe_close_above_stdio(int fd) {
  20         if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
  21                 return -1;
  22
  23         return safe_close(fd);
  24 }
  25
  26 void close_many(const int fds[], size_t n_fd);
  27
  28 int fclose_nointr(FILE *f);
  29 FILE* safe_fclose(FILE *f);
  30 DIR* safe_closedir(DIR *f);
  31
  32 static inline void closep(int *fd) {
  33         safe_close(*fd);
  34 }
  35
  36 static inline void close_pairp(int (*p)[2]) {
  37         safe_close_pair(*p);
  38 }
  39
  40 static inline void fclosep(FILE **f) {
  41         safe_fclose(*f);
  42 }
  43
  44 DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, pclose);
  45 DEFINE_TRIVIAL_CLEANUP_FUNC(DIR*, closedir);
  46
  47 #define _cleanup_close_ _cleanup_(closep)
  48 #define _cleanup_fclose_ _cleanup_(fclosep)
  49 #define _cleanup_pclose_ _cleanup_(pclosep)
  50 #define _cleanup_closedir_ _cleanup_(closedirp)
  51 #define _cleanup_close_pair_ _cleanup_(close_pairp)
  52
  53 int fd_nonblock(int fd, bool nonblock);
  54 int fd_cloexec(int fd, bool cloexec);
  55
  56 int close_all_fds(const int except[], size_t n_except);
  57
  58 int same_fd(int a, int b);
  59
  60 void cmsg_close_all(struct msghdr *mh);
  61
  62 bool fdname_is_valid(const char *s);
  63
  64 int fd_get_path(int fd, char **ret);
  65
  66 int move_fd(int from, int to, int cloexec);
  67
  68 enum {
  69         ACQUIRE_NO_DEV_NULL = 1 << 0,
  70         ACQUIRE_NO_MEMFD    = 1 << 1,
  71         ACQUIRE_NO_PIPE     = 1 << 2,
  72         ACQUIRE_NO_TMPFILE  = 1 << 3,
  73         ACQUIRE_NO_REGULAR  = 1 << 4,
  74 };
  75
  76 int acquire_data_fd(const void *data, size_t size, unsigned flags);
  77
  78 int fd_duplicate_data_fd(int fd);
  79
  80 /* Hint: ENETUNREACH happens if we try to connect to "non-existing" special IP addresses, such as ::5 */
  81 /* The kernel sends e.g., EHOSTUNREACH or ENONET to userspace in some ICMP error cases.
  82  * See the icmp_err_convert[] in net/ipv4/icmp.c in the kernel sources */
  83 #define ERRNO_IS_DISCONNECT(r)                                          \
  84         IN_SET(r,                                                       \
  85                ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE, \
  86                ENETUNREACH, EHOSTUNREACH, ENOPROTOOPT, EHOSTDOWN, ENONET)
  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);
 109
 110 int read_nr_open(void);