/*      $OpenBSD: pwritev.c,v 1.5 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 <string.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{       
        char temp[] = "/tmp/pwritevXXXXXXXXX";
        char magic[10] = "0123456789";
        const char zeroes[10] = "0000000000";
        char buf[10];
        struct iovec iov[2];
        char c;
        int fd, ret;

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

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

        if (lseek(fd, 5, SEEK_SET) != 5)
                err(1, "lseek");

        iov[0].iov_base = &magic[8];
        iov[0].iov_len = 2;
        iov[1].iov_base = &magic[7];
        iov[1].iov_len = 2;

        if (pwritev(fd, iov, 2, 4) != 4)
                err(1, "pwritev");

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

        if (c != '9')
                errx(1, "read %c != %c", c, '9');

        c = '5';
        if (write(fd, &c, 1) != 1)
                err(1, "write");

        if (pread(fd, buf, 10, 0) != 10)
                err(1, "pread");

        iov[1].iov_base = &magic[1];
        iov[1].iov_len = 2;
        if ((ret = pwritev(fd, iov, 2, -1)) != -1)
                errx(1, "pwritev with negative offset succeeded,\
                                returning %d", ret);
        if (errno != EINVAL)
                err(1, "pwritev with negative offset");

        if ((ret = pwritev(fd, iov, 2, LLONG_MAX)) != -1)
                errx(1, "pwritev with wrapping offset succeeded,\
                                returning %d", ret);
        if (errno != EFBIG && errno != EINVAL)
                err(1, "pwritev with wrapping offset");

        if (memcmp(buf, "0000895800", 10) != 0)
                errx(1, "data mismatch: %s != %s", buf, "0000895800");

        /* pwrite should be unaffected by O_APPEND */
        if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_APPEND))
                err(1, "fcntl");
        if (pwritev(fd, iov, 2, 2) != 4)
                err(1, "pwritev");
        if (pread(fd, buf, 10, 0) != 10)
                err(1, "pread");
        if (memcmp(buf, "0089125800", 10) != 0)
                errx(1, "data mismatch: %s != %s", buf, "0089125800");

        close(fd);

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

        return 0;
}