/*      $OpenBSD: open.c,v 1.2 2026/03/28 07:23:57 dgl Exp $    */
/*
 * Copyright (c) 2026 David Leadbeater <dgl@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/stat.h>

#include <err.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>

/*
 * __pledge_open(2) is libc internal. This is for testing kernel semantics
 * only, do not use this outside of regress.
 */
int _libc___pledge_open(char *path, int flags, ...);

#define NO_PLEDGE "[NO PLEDGE]"

int
main(int argc, char **argv)
{
        int fd, i;
        char *promise, *path;
        struct stat sb;

        if (argc < 3)
                errx(1, "argc: %d", argc);

        promise = argv[1];
        path = argv[2];

        if (((argc - 3) % 2) != 0)
                errx(1, "unveil(x, y) must be balanced");

        for (i = 3; i < argc; i += 2) {
                if (unveil(argv[i], argv[i+1]) == -1)
                        err(1, "unveil(%s, %s)", argv[i], argv[i+1]);
        }

        if (strcmp(promise, NO_PLEDGE) != 0 && pledge(promise, NULL) == -1)
                err(1, "pledge %s", promise);

        fd = _libc___pledge_open(path, O_RDONLY);
        if (fd == -1)
                err(2, "open %s", path);

        if (fstat(fd, &sb) == -1)
                err(3, "fstat %s", path);

        /* __pledge_open marks fds so certain operations are not allowed. */
        if (strcmp(promise, NO_PLEDGE) != 0 && S_ISREG(sb.st_mode))
                if (fchmod(fd, 0) != -1)
                        errx(4, "fchmod succeeded");
}