tools/testing/selftests/splice/splice_read.c

   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
  12 int 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 }