io/sendfile.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2004-2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6
   7 #include "command.h"
   8 #include "input.h"
   9 #include <sys/sendfile.h>
  10 #include "init.h"
  11 #include "io.h"
  12
  13 static cmdinfo_t sendfile_cmd;
  14
  15 static void
  16 sendfile_help(void)
  17 {
  18         printf(_(
  19 "\n"
  20 " transfer a range of bytes from the given offset between files\n"
  21 "\n"
  22 " Example:\n"
  23 " 'send -f 2 512 20' - writes 20 bytes at 512 bytes into the open file\n"
  24 "\n"
  25 " Copies data between one file descriptor and another.  Because this copying\n"
  26 " is done within the kernel, sendfile does not need to transfer data to and\n"
  27 " from user space.\n"
  28 " -f -- specifies an input file from which to source data to write\n"
  29 " -i -- specifies an input file name from which to source data to write.\n"
  30 " An offset and length in the source file can be optionally specified.\n"
  31 "\n"));
  32 }
  33
  34 static int
  35 send_buffer(
  36         off64_t         offset,
  37         size_t          count,
  38         int             fd,
  39         long long       *total)
  40 {
  41         off64_t         off = offset;
  42         ssize_t         bytes, bytes_remaining = count;
  43         int             ops = 0;
  44
  45         *total = 0;
  46         while (count > 0) {
  47                 bytes = sendfile(file->fd, fd, &off, bytes_remaining);
  48                 if (bytes == 0)
  49                         break;
  50                 if (bytes < 0) {
  51                         perror("sendfile");
  52                         return -1;
  53                 }
  54                 ops++;
  55                 *total += bytes;
  56                 if (bytes >= bytes_remaining)
  57                         break;
  58                 bytes_remaining -= bytes;
  59         }
  60         return ops;
  61 }
  62
  63 static int
  64 sendfile_f(
  65         int             argc,
  66         char            **argv)
  67 {
  68         off64_t         offset = 0;
  69         long long       count, total;
  70         size_t          blocksize, sectsize;
  71         struct timeval  t1, t2;
  72         char            *infile = NULL;
  73         int             Cflag, qflag;
  74         int             c, fd = -1;
  75
  76         Cflag = qflag = 0;
  77         init_cvtnum(&blocksize, &sectsize);
  78         while ((c = getopt(argc, argv, "Cf:i:q")) != EOF) {
  79                 switch (c) {
  80                 case 'C':
  81                         Cflag = 1;
  82                         break;
  83                 case 'q':
  84                         qflag = 1;
  85                         break;
  86                 case 'f':
  87                         fd = atoi(argv[1]);
  88                         if (fd < 0 || fd >= filecount) {
  89                                 printf(_("value %d is out of range (0-%d)\n"),
  90                                         fd, filecount-1);
  91                                 return 0;
  92                         }
  93                         break;
  94                 case 'i':
  95                         infile = optarg;
  96                         break;
  97                 default:
  98                         return command_usage(&sendfile_cmd);
  99                 }
 100         }
 101         if (infile && fd != -1)
 102                 return command_usage(&sendfile_cmd);
 103
 104         if (!infile)
 105                 fd = filetable[fd].fd;
 106         else if ((fd = openfile(infile, NULL, IO_READONLY, 0, NULL)) < 0)
 107                 return 0;
 108
 109         if (optind == argc - 2) {
 110                 offset = cvtnum(blocksize, sectsize, argv[optind]);
 111                 if (offset < 0) {
 112                         printf(_("non-numeric offset argument -- %s\n"),
 113                                 argv[optind]);
 114                         goto done;
 115                 }
 116                 optind++;
 117                 count = cvtnum(blocksize, sectsize, argv[optind]);
 118                 if (count < 0) {
 119                         printf(_("non-numeric length argument -- %s\n"),
 120                                 argv[optind]);
 121                         goto done;
 122                 }
 123         } else {
 124                 struct stat     stat;
 125
 126                 if (fstat(fd, &stat) < 0) {
 127                         perror("fstat");
 128                         goto done;
 129                 }
 130                 count = stat.st_size;
 131         }
 132
 133         gettimeofday(&t1, NULL);
 134         c = send_buffer(offset, count, fd, &total);
 135         if (c < 0)
 136                 goto done;
 137         if (qflag)
 138                 goto done;
 139         gettimeofday(&t2, NULL);
 140         t2 = tsub(t2, t1);
 141
 142         report_io_times("sent", &t2, (long long)offset, count, total, c, Cflag);
 143 done:
 144         if (infile)
 145                 close(fd);
 146         return 0;
 147 }
 148
 149 void
 150 sendfile_init(void)
 151 {
 152         sendfile_cmd.name = "sendfile";
 153         sendfile_cmd.altname = "send";
 154         sendfile_cmd.cfunc = sendfile_f;
 155         sendfile_cmd.argmin = 2;
 156         sendfile_cmd.argmax = -1;
 157         sendfile_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
 158         sendfile_cmd.args =
 159                 _("-i infile | -f N [off len]");
 160         sendfile_cmd.oneline =
 161                 _("Transfer data directly between file descriptors");
 162         sendfile_cmd.help = sendfile_help;
 163
 164         add_command(&sendfile_cmd);
 165 }