/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2025 Oxide Computer Company
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <strings.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/modctl.h>
#include <zone.h>
#include <spawn.h>
#include <err.h>
#include <stdbool.h>


static void
usage(void)
{
        (void) fprintf(stderr,
            "usage:  modunload [-e <exec_file>] -i <id> | <name>\n");
        exit(EXIT_FAILURE);
}

/*
 * Execute the user file.
 */
static void
exec_userfile(char *execfile, const struct modinfo *modinfo, char **envp)
{
        char modid[8], mod0[8];
        char *child_args[] = {execfile, modid, mod0, NULL};

        (void) snprintf(modid, sizeof (modid), "%d", modinfo->mi_id);
        (void) snprintf(mod0, sizeof (mod0), "%d",
            modinfo->mi_msinfo[0].msi_p0);

        const short desired_attrs =
            POSIX_SPAWN_NOSIGCHLD_NP | POSIX_SPAWN_WAITPID_NP;
        posix_spawnattr_t attr;
        int res;
        if ((res = posix_spawnattr_init(&attr)) != 0 ||
            (res = posix_spawnattr_setflags(&attr, desired_attrs)) != 0) {
                errc(EXIT_FAILURE, res, "could not set spawn attrs");
        }

        pid_t child;
        if (posix_spawn(&child, execfile, NULL, &attr, child_args, envp) != 0) {
                err(EXIT_FAILURE, "could not exec %s", execfile);
        }
        (void) posix_spawnattr_destroy(&attr);

        int status, error;
        do {
                error = waitpid(child, &status, 0);
        } while (error == -1 && errno == EINTR);
        if (error < 0) {
                err(EXIT_FAILURE, "error while waiting for child");
        }

        if (WEXITSTATUS(status) != 0) {
                errx(WEXITSTATUS(status),
                    "%s returned error %d.", execfile, status);
        }
}

/*
 * Unload a loaded module.
 */
int
main(int argc, char *argv[], char *envp[])
{
        int id = -1;
        char *execfile = NULL;
        char *unload_name = NULL;
        int opt;
        bool has_mod_id = false;

        if (argc < 2)
                usage();

        while ((opt = getopt(argc, argv, "i:e:")) != -1) {
                switch (opt) {
                case 'i':
                        if (has_mod_id) {
                                errx(EXIT_FAILURE,
                                    "Only one module id can be specified");
                        }
                        if (sscanf(optarg, "%d", &id) != 1 || id < 0)
                                errx(EXIT_FAILURE, "Invalid id %s", optarg);
                        has_mod_id = true;
                        break;
                case 'e':
                        execfile = optarg;
                        break;
                case '?':
                        usage();
                        break;
                }
        }
        argc -= optind;
        argv += optind;

        if (argc == 1) {
                unload_name = argv[0];
        } else if (argc > 1) {
                errx(EXIT_FAILURE, "Only one module name can be specified");
        }

        /* One must specify a name (x)or an ID, not both */
        if (unload_name == NULL && !has_mod_id) {
                (void) fprintf(stderr,
                    "missing required module id or name\n");
                usage();
        } else if (unload_name != NULL && has_mod_id) {
                (void) fprintf(stderr,
                    "invalid to specify both module id and name\n");
                usage();
        }

        if (getzoneid() != GLOBAL_ZONEID) {
                errx(EXIT_FAILURE,
                    "modunload can only be run from the global zone");
        }

        struct modinfo modinfo;
        if (execfile != NULL || unload_name != NULL) {
                modinfo.mi_id = modinfo.mi_nextid = id;
                modinfo.mi_info = MI_INFO_ONE;
                if (unload_name != NULL) {
                        (void) strlcpy(modinfo.mi_name, unload_name,
                            sizeof (modinfo.mi_name));
                        modinfo.mi_info |= MI_INFO_BY_NAME;
                }
                if (modctl(MODINFO, id, &modinfo) < 0) {
                        err(EXIT_FAILURE, "can't get module information");
                }
                if (unload_name != NULL) {
                        id = modinfo.mi_id;
                }
        }

        if (execfile) {
                exec_userfile(execfile, &modinfo, envp);
        }

        /*
         * Unload the module.
         */
        if (modctl(MODUNLOAD, id) < 0) {
                if (errno == EPERM) {
                        errx(EXIT_FAILURE,
                            "Insufficient privileges to unload a module");
                } else if (id != 0) {
                        err(EXIT_FAILURE, "can't unload the module");
                }
        }

        return (EXIT_SUCCESS);
}