/*      $OpenBSD: preadv.c,v 1.4 2011/11/06 15:00:34 guenther Exp $     */
/*
 *      Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
 */
#include <sys/types.h>
#include <sys/uio.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{       
        char temp[] = "/tmp/dup2XXXXXXXXX";
        const char magic[10] = "0123456789";
        char c, c1, c2;
        int fd, ret;
        struct iovec iv[2];

        if ((fd = mkstemp(temp)) < 0)
                err(1, "mkstemp");
        remove(temp);

        if (write(fd, magic, sizeof(magic)) != sizeof(magic))
                err(1, "write");

        if (lseek(fd, 0, SEEK_SET) != 0)
                err(1, "lseek");

        if (read(fd, &c, 1) != 1)
                err(1, "read1");

        if (c != magic[0])
                errx(1, "read1 %c != %c", c, magic[0]);

        iv[0].iov_base = &c1;
        iv[0].iov_len = 1;
        iv[1].iov_base = &c2;
        iv[1].iov_len = 1;

        if (preadv(fd, iv, 2, 7) != 2)
                err(1, "preadv");

        if (c1 != magic[7])
                errx(1, "preadv %c != %c", c1, magic[7]);

        if (c2 != magic[8])
                errx(1, "preadv %c != %c", c2, magic[7]);

        if (read(fd, &c, 1) != 1)
                err(1, "read2");

        if (c != magic[1])
                errx(1, "read2 %c != %c", c, magic[1]);

        if ((ret = preadv(fd, iv, 2, -1)) != -1)
                errx(1, "preadv with negative offset succeeded,\
                                returning %d", ret);
        if (errno != EINVAL)
                err(1, "pread with negative offset");

        if ((ret = preadv(fd, iv, 2, LLONG_MAX)) != -1)
                errx(1, "preadv with wrapping offset succeeded,\
                                returning %d", ret);
        if (errno != EINVAL)
                err(1, "pread with wrapping offset");

        if (read(fd, &c, 1) != 1)
                err(1, "read3");

        if (c != magic[2])
                errx(1, "read3 %c != %c", c, magic[2]);

        close(fd);

        /* also, verify that preadv fails on ttys */
        fd = open("/dev/tty", O_RDWR);
        if (fd < 0)
                printf("skipping tty test\n");
        else if ((ret = preadv(fd, iv, 2, 7)) != -1)
                errx(1, "preadv succeeded on tty, returning %d", ret);
        else if (errno != ESPIPE)
                err(1, "preadv");

        return 0;
}