/*      $NetBSD: devpubd.c,v 1.7 2021/06/21 03:14:12 christos Exp $     */

/*-
 * Copyright (c) 2011 Jared D. McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__COPYRIGHT("@(#) Copyright (c) 2011-2015\
Jared D. McNeill <jmcneill@invisible.ca>. All rights reserved.");
__RCSID("$NetBSD: devpubd.c,v 1.7 2021/06/21 03:14:12 christos Exp $");

#include <sys/queue.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/drvctlio.h>
#include <sys/wait.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

static int drvctl_fd = -1;
static const char devpubd_script[] = DEVPUBD_RUN_HOOKS;

struct devpubd_probe_event {
        char *device;
        TAILQ_ENTRY(devpubd_probe_event) entries;
};

static TAILQ_HEAD(, devpubd_probe_event) devpubd_probe_events;

#define DEVPUBD_ATTACH_EVENT    "device-attach"
#define DEVPUBD_DETACH_EVENT    "device-detach"

__dead static void
devpubd_exec(const char *path, char * const *argv)
{
        int error;

        error = execv(path, argv);
        if (error) {
                syslog(LOG_ERR, "couldn't exec '%s': %m", path);
                exit(EXIT_FAILURE);
        }

        exit(EXIT_SUCCESS);
}

static void
devpubd_eventhandler(const char *event, const char **device)
{
        char **argv;
        pid_t pid;
        int status;
        size_t i, ndevs;

        for (ndevs = 0, i = 0; device[i] != NULL; i++) {
                ++ndevs;
                syslog(LOG_DEBUG, "event = '%s', device = '%s'", event,
                    device[i]);
        }

        argv = calloc(3 + ndevs, sizeof(*argv));
        argv[0] = __UNCONST(devpubd_script);
        argv[1] = __UNCONST(event);
        for (i = 0; i < ndevs; i++) {
                argv[2 + i] = __UNCONST(device[i]);
        }
        argv[2 + i] = NULL;

        pid = fork();
        switch (pid) {
        case -1:
                syslog(LOG_ERR, "fork failed: %m");
                break;
        case 0:
                devpubd_exec(devpubd_script, argv);
                /* NOTREACHED */
        default:
                if (waitpid(pid, &status, 0) == -1) {
                        syslog(LOG_ERR, "waitpid(%d) failed: %m", pid);
                        break;
                }
                if (WIFEXITED(status) && WEXITSTATUS(status)) {
                        syslog(LOG_WARNING, "%s exited with status %d",
                            devpubd_script, WEXITSTATUS(status));
                } else if (WIFSIGNALED(status)) {
                        syslog(LOG_WARNING, "%s received signal %d",
                            devpubd_script, WTERMSIG(status));
                }
                break;
        }

        free(argv);
}

__dead static void
devpubd_eventloop(void)
{
        const char *event, *device[2];
        prop_dictionary_t ev;
        int res;

        assert(drvctl_fd != -1);

        device[1] = NULL;

        for (;;) {
                res = prop_dictionary_recv_ioctl(drvctl_fd, DRVGETEVENT, &ev);
                if (res)
                        err(EXIT_FAILURE, "DRVGETEVENT failed");
                prop_dictionary_get_string(ev, "event", &event);
                prop_dictionary_get_string(ev, "device", &device[0]);

                printf("%s: event='%s', device='%s'\n", __func__,
                    event, device[0]);

                devpubd_eventhandler(event, device);

                prop_object_release(ev);
        }
}

static void
devpubd_probe(const char *device)
{
        struct devlistargs laa;
        size_t len, children, n;
        void *p;
        int error;

        assert(drvctl_fd != -1);

        memset(&laa, 0, sizeof(laa));
        if (device)
                strlcpy(laa.l_devname, device, sizeof(laa.l_devname));

        /* Get the child device count for this device */
        error = ioctl(drvctl_fd, DRVLISTDEV, &laa);
        if (error) {
                syslog(LOG_ERR, "DRVLISTDEV failed: %m");
                return;
        }

child_count_changed:
        /* If this device has no children, return */
        if (laa.l_children == 0)
                return;

        /* Allocate a buffer large enough to hold the child device names */
        p = laa.l_childname;
        children = laa.l_children;

        len = children * sizeof(laa.l_childname[0]);
        laa.l_childname = realloc(laa.l_childname, len);
        if (laa.l_childname == NULL) {
                syslog(LOG_ERR, "couldn't allocate %zu bytes", len);
                laa.l_childname = p;
                goto done;
        }

        /* Get a list of child devices */
        error = ioctl(drvctl_fd, DRVLISTDEV, &laa);
        if (error) {
                syslog(LOG_ERR, "DRVLISTDEV failed: %m");
                goto done;
        }

        /* If the child count changed between DRVLISTDEV calls, retry */
        if (children != laa.l_children)
                goto child_count_changed;

        /*
         * For each child device, queue an attach event and
         * then scan each one for additional devices.
         */
        for (n = 0; n < laa.l_children; n++) {
                struct devpubd_probe_event *ev = calloc(1, sizeof(*ev));
                ev->device = strdup(laa.l_childname[n]);
                TAILQ_INSERT_TAIL(&devpubd_probe_events, ev, entries);
        }
        for (n = 0; n < laa.l_children; n++)
                devpubd_probe(laa.l_childname[n]);

done:
        free(laa.l_childname);
        return;
}

static void
devpubd_init(void)
{
        struct devpubd_probe_event *ev;
        const char **devs;
        size_t ndevs, i;

        TAILQ_INIT(&devpubd_probe_events);
        devpubd_probe(NULL);
        ndevs = 0;
        TAILQ_FOREACH(ev, &devpubd_probe_events, entries) {
                ++ndevs;
        }
        devs = calloc(ndevs + 1, sizeof(*devs));
        i = 0;
        TAILQ_FOREACH(ev, &devpubd_probe_events, entries) {
                devs[i++] = ev->device;
        }
        devpubd_eventhandler(DEVPUBD_ATTACH_EVENT, devs);
        free(devs);
        while ((ev = TAILQ_FIRST(&devpubd_probe_events)) != NULL) {
                TAILQ_REMOVE(&devpubd_probe_events, ev, entries);
                free(ev->device);
                free(ev);
        }
}

__dead static void
usage(void)
{
        fprintf(stderr, "usage: %s [-1f]\n", getprogname());
        exit(EXIT_FAILURE);
}

int
main(int argc, char *argv[])
{
        bool fflag = false;
        bool once = false;
        int ch;

        setprogname(argv[0]);

        while ((ch = getopt(argc, argv, "1fh")) != -1) {
                switch (ch) {
                case '1':
                        fflag = true;
                        once = true;
                        break;
                case 'f':
                        fflag = true;
                        break;
                case 'h':
                default:
                        usage();
                        /* NOTREACHED */
                }
        }
        argc -= optind;
        argv += optind;

        if (argc)
                usage();
                /* NOTREACHED */

        drvctl_fd = open(DRVCTLDEV, O_RDWR);
        if (drvctl_fd == -1)
                err(EXIT_FAILURE, "couldn't open " DRVCTLDEV);

        /* Look for devices that are already present */
        devpubd_init();

        if (!fflag) {
                if (daemon(0, 0) == -1) {
                        err(EXIT_FAILURE, "couldn't fork");
                }
        }

        if (!once)
                devpubd_eventloop();

        return EXIT_SUCCESS;
}