/*      $OpenBSD: pwrite.c,v 1.6 2014/02/28 16:14:05 espie Exp $        */
/*
 *      Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
 */
#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/pwriteXXXXXXXXX";
        const char magic[10] = "0123456789";
        const char zeroes[10] = "0000000000";
        char buf[10];
        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");

        if (pwrite(fd, &magic[1], 4, 4) != 4)
                err(1, "pwrite");

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

        if (c != '2')
                errx(1, "read %c != %c", c, '2');

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

        if (write(fd, &c, 0) != 0)
                err(1, "write");

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

        if (memcmp(buf, "0000125400", 10) != 0)
                errx(1, "data mismatch: %s != %s", buf, "0000125400");

        if ((ret = pwrite(fd, &magic[5], 1, -1)) != -1)
                errx(1, "pwrite with negative offset succeeded,\
                                returning %d", ret);
        if (errno != EINVAL)
                err(1, "pwrite with negative offset");

        if ((ret = pwrite(fd, &magic[5], 1, LLONG_MAX)) != -1)
                errx(1, "pwrite with wrapping offset succeeded,\
                                returning %d", ret);
        if (errno != EFBIG && errno != EINVAL)
                err(1, "pwrite with wrapping offset");

        /* pwrite should be unaffected by O_APPEND */
        if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_APPEND))
                err(1, "fcntl");
        if (pwrite(fd, &magic[2], 3, 2) != 3)
                err(1, "pwrite");
        if (pread(fd, buf, 10, 0) != 10)
                err(1, "pread");
        if (memcmp(buf, "0023425400", 10) != 0)
                errx(1, "data mismatch: %s != %s", buf, "0023425400");

        close(fd);

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

        return 0;
}