src/basic/io-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 <stdbool.h>
  11 #include <stddef.h>
  12 #include <stdint.h>
  13 #include <sys/types.h>
  14 #include <sys/uio.h>
  15
  16 #include "macro.h"
  17 #include "time-util.h"
  18
  19 int flush_fd(int fd);
  20
  21 ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll);
  22 int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll);
  23 int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll);
  24
  25 int pipe_eof(int fd);
  26
  27 int fd_wait_for_event(int fd, int event, usec_t timeout);
  28
  29 ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length);
  30
  31 static inline size_t IOVEC_TOTAL_SIZE(const struct iovec *i, size_t n) {
  32         size_t j, r = 0;
  33
  34         for (j = 0; j < n; j++)
  35                 r += i[j].iov_len;
  36
  37         return r;
  38 }
  39
  40 static inline size_t IOVEC_INCREMENT(struct iovec *i, size_t n, size_t k) {
  41         size_t j;
  42
  43         for (j = 0; j < n; j++) {
  44                 size_t sub;
  45
  46                 if (_unlikely_(k <= 0))
  47                         break;
  48
  49                 sub = MIN(i[j].iov_len, k);
  50                 i[j].iov_len -= sub;
  51                 i[j].iov_base = (uint8_t*) i[j].iov_base + sub;
  52                 k -= sub;
  53         }
  54
  55         return k;
  56 }
  57
  58 static inline bool FILE_SIZE_VALID(uint64_t l) {
  59         /* ftruncate() and friends take an unsigned file size, but actually cannot deal with file sizes larger than
  60          * 2^63 since the kernel internally handles it as signed value. This call allows checking for this early. */
  61
  62         return (l >> 63) == 0;
  63 }
  64
  65 static inline bool FILE_SIZE_VALID_OR_INFINITY(uint64_t l) {
  66
  67         /* Same as above, but allows one extra value: -1 as indication for infinity. */
  68
  69         if (l == (uint64_t) -1)
  70                 return true;
  71
  72         return FILE_SIZE_VALID(l);
  73
  74 }
  75
  76 #define IOVEC_INIT(base, len) { .iov_base = (base), .iov_len = (len) }
  77 #define IOVEC_MAKE(base, len) (struct iovec) IOVEC_INIT(base, len)
  78 #define IOVEC_INIT_STRING(string) IOVEC_INIT((char*) string, strlen(string))
  79 #define IOVEC_MAKE_STRING(string) (struct iovec) IOVEC_INIT_STRING(string)