1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11 
  12 /*
  13  * Copyright 2020 Joyent, Inc.
  14  */
  15 
  16 /*
  17  * Some simple testing of the read/writev() family: specifically we're checking
  18  * IOV_MAX == 1024, and that a large-file compiled 32-bit binary can correctly
  19  * access certain offsets.
  20  */
  21 
  22 #include <sys/uio.h>
  23 #include <strings.h>
  24 #include <limits.h>
  25 #include <unistd.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <err.h>
  30 
  31 #define ONE_GIG ((off_t)1024 * 1024 * 1024)
  32 
  33 #define DATA_LEN (sizeof ("data"))
  34 
  35 char path[] = "/var/tmp/writev_test.XXXXXX";
  36 
  37 static void
  38 cleanup(void)
  39 {
  40         (void) unlink(path);
  41 }
  42 
  43 int
  44 main(int argc, char *argv[])
  45 {
  46         char data[(IOV_MAX + 1) * DATA_LEN] = "";
  47         struct iovec iov[IOV_MAX + 1];
  48 
  49         if (IOV_MAX != 1024)
  50                 errx(EXIT_FAILURE, "IOV_MAX != 1024");
  51 
  52         int fd = mkstemp(path);
  53 
  54         if (fd == -1)
  55                 err(EXIT_FAILURE, "failed to create file");
  56 
  57         (void) atexit(cleanup);
  58 
  59         int ret = ftruncate(fd, ONE_GIG * 8);
  60 
  61         if (ret != 0)
  62                 err(EXIT_FAILURE, "failed to truncate file");
  63 
  64         for (int i = 0; i < IOV_MAX + 1; i++) {
  65                 (void) strcpy(data + i * DATA_LEN, "data");
  66                 iov[i].iov_base = data + i * 5;
  67                 iov[i].iov_len = DATA_LEN;
  68         }
  69 
  70         ssize_t written = writev(fd, iov, IOV_MAX + 1);
  71 
  72         if (written != -1 || errno != EINVAL)
  73                 errx(EXIT_FAILURE, "writev(IOV_MAX + 1) didn't fail properly");
  74 
  75         written = writev(fd, iov, IOV_MAX);
  76 
  77         if (written == -1)
  78                 err(EXIT_FAILURE, "writev failed");
  79 
  80         bzero(data, sizeof (data));
  81 
  82         ssize_t read = preadv(fd, iov, IOV_MAX, 0);
  83 
  84         if (read != DATA_LEN * IOV_MAX)
  85                 err(EXIT_FAILURE, "preadv failed");
  86 
  87         for (int i = 0; i < IOV_MAX; i++) {
  88                 if (strcmp(data + i * DATA_LEN, "data") != 0)
  89                         errx(EXIT_FAILURE, "bad read at 0x%lx", i * DATA_LEN);
  90         }
  91 
  92         /*
  93          * Now test various "interesting" offsets.
  94          */
  95 
  96         for (off_t off = 0; off < ONE_GIG * 8; off += ONE_GIG) {
  97                 if ((written = pwritev(fd, iov, 1, off)) != DATA_LEN)
  98                         err(EXIT_FAILURE, "pwritev(0x%lx) failed", off);
  99         }
 100 
 101         for (off_t off = 0; off < ONE_GIG * 8; off += ONE_GIG) {
 102                 if ((read = preadv(fd, iov, 1, off)) != DATA_LEN)
 103                         err(EXIT_FAILURE, "preadv(0x%lx) failed", off);
 104                 if (strcmp(data, "data") != 0)
 105                         errx(EXIT_FAILURE, "bad read at 0x%lx", off);
 106         }
 107 
 108         return (EXIT_SUCCESS);
 109 }