LXR linux/tools/testing/selftests/splice/splice

   1// SPDX-License-Identifier: GPL-2.0
   2#define _GNU_SOURCE
   3#include <errno.h>
   4#include <fcntl.h>
   5#include <limits.h>
   6#include <stdio.h>
   7#include <stdlib.h>
   8#include <unistd.h>
   9#include <sys/types.h>
  10#include <sys/stat.h>
  11
  12int main(int argc, char *argv[])
  13{
  14        int fd;
  15        size_t size;
  16        ssize_t spliced;
  17
  18        if (argc < 2) {
  19                fprintf(stderr, "Usage: %s INPUT [BYTES]\n", argv[0]);
  20                return EXIT_FAILURE;
  21        }
  22
  23        fd = open(argv[1], O_RDONLY);
  24        if (fd < 0) {
  25                perror(argv[1]);
  26                return EXIT_FAILURE;
  27        }
  28
  29        if (argc == 3)
  30                size = atol(argv[2]);
  31        else {
  32                struct stat statbuf;
  33
  34                if (fstat(fd, &statbuf) < 0) {
  35                        perror(argv[1]);
  36                        return EXIT_FAILURE;
  37                }
  38
  39                if (statbuf.st_size > INT_MAX) {
  40                        fprintf(stderr, "%s: Too big\n", argv[1]);
  41                        return EXIT_FAILURE;
  42                }
  43
  44                size = statbuf.st_size;
  45        }
  46
  47        /* splice(2) file to stdout. */
  48        spliced = splice(fd, NULL, STDOUT_FILENO, NULL,
  49                      size, SPLICE_F_MOVE);
  50        if (spliced < 0) {
  51                perror("splice");
  52                return EXIT_FAILURE;
  53        }
  54
  55        close(fd);
  56        return EXIT_SUCCESS;
  57}
  58