splice/splice2.c

   1 #define _GNU_SOURCE
   2 #include <unistd.h>
   3 #include <fcntl.h>
   4 #include <sys/uio.h>
   5 #include <stdlib.h>
   6 #include <stdio.h>
   7 #include <errno.h>
   8 #include <string.h>
   9 #include <stdint.h>
  10 #include <sys/socket.h>
  11 #include <sys/sendfile.h>
  12
  13 int main(int argc, const char * const *argv)
  14 {
  15         int pfd[2];
  16         int zfd;
  17         int nfd;
  18         size_t i;
  19         size_t total_size;
  20         size_t current_size = 0;
  21         uint8_t *buffer = NULL;;
  22         size_t buffer_size;
  23
  24         if (argc != 4) {
  25                 printf("%s: usage %s <'splice'|'rw'> <total_size> <buffer_size>\n",
  26                         argv[0], argv[0]);
  27                 exit(1);
  28         }
  29
  30         total_size = strtoull(argv[2], NULL, 0);
  31         buffer_size = strtoull(argv[3], NULL, 0);
  32
  33         if (strcmp(argv[1], "splice") == 0) {
  34                 pipe(pfd);
  35                 fcntl(pfd[1], F_SETPIPE_SZ, buffer_size);
  36                 buffer_size = fcntl(pfd[1], F_GETPIPE_SZ);
  37         } else {
  38                 buffer = malloc(buffer_size);
  39         }
  40
  41         zfd = open("/dev/zero", O_RDONLY);
  42         nfd = open("/dev/null", O_WRONLY);
  43
  44         while (current_size < total_size) {
  45                 ssize_t zret;
  46                 ssize_t nret;
  47
  48                 errno = 0;
  49                 if (buffer) {
  50                         zret = read(zfd, buffer, buffer_size);
  51                 } else {
  52                         zret = splice(zfd, NULL, pfd[1], NULL,
  53                                       buffer_size, SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
  54                 }
  55                 if (zret < 0) {
  56                         printf("%d: zret[%lld] errno[%d/%s]\n", __LINE__,
  57                                 (long long int)zret, errno, strerror(errno));
  58                         break;
  59                 }
  60
  61                 errno = 0;
  62                 if (buffer) {
  63                         nret = write(nfd, buffer, zret);
  64                 } else {
  65                         nret = splice(pfd[0], NULL, nfd, NULL,
  66                                       zret, SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
  67                 }
  68                 if (nret < 0) {
  69                         printf("%d: nret[%lld] errno[%d/%s]\n", __LINE__,
  70                                 (long long int)nret, errno, strerror(errno));
  71                         break;
  72                 }
  73                 if (nret != zret) {
  74                         printf("%d: zret[%lld] nret[%lld]\n", __LINE__,
  75                                 (long long int)zret,
  76                                 (long long int)nret);
  77                         break;
  78                 }
  79
  80                 current_size += nret;
  81                 i++;
  82         }
  83
  84         printf("%s: i[%lld] total_size[%lld] buffer_size[%lld => %lld]\n",
  85                 argv[1],
  86                 (long long int)i,
  87                 (long long int)total_size,
  88                 (long long int)buffer_size,
  89                 (long long int)(total_size/i));
  90         return 0;
  91 }