/* vi: set sw=4 ts=4: */
/*
 * Mini rmmod implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <string.h>
#include <sys/utsname.h>
#include <sys/syscall.h>
#include "busybox.h"

#ifdef CONFIG_FEATURE_2_6_MODULES
static inline void filename2modname(char *modname, const char *filename)
{
	const char *afterslash;
	unsigned int i;

	afterslash = strrchr(filename, '/');
	if (!afterslash)
		afterslash = filename;
	else
		afterslash++;

	/* Convert to underscores, stop at first . */
	for (i = 0; afterslash[i] && afterslash[i] != '.'; i++) {
		int kr_chk = 1;

		if (ENABLE_FEATURE_2_4_MODULES) {
			struct utsname uname_info;
			if (uname(&uname_info) == -1)
				bb_error_msg_and_die("cannot get uname data");
			if (strcmp(uname_info.release, "2.6") < 0)
				kr_chk = 0;
		}
		if (kr_chk && (afterslash[i] == '-'))
			modname[i] = '_';
		else
			modname[i] = afterslash[i];
	}
	modname[i] = '\0';
}
#endif

extern int rmmod_main(int argc, char **argv)
{
	int n, ret = EXIT_SUCCESS;
	size_t nmod = 0; /* number of modules */
	size_t pnmod = -1; /* previous number of modules */
	unsigned int flags = O_NONBLOCK|O_EXCL;
#ifdef CONFIG_FEATURE_QUERY_MODULE_INTERFACE
	void *buf; /* hold the module names which we ignore but must get */
	size_t bufsize = 0;
#endif

	/* Parse command line. */
	while ((n = getopt(argc, argv, "a")) != EOF) {
		switch (n) {
			case 'w':       // --wait
				flags &= ~O_NONBLOCK;
				break;
			case 'f':       // --force
				flags |= O_TRUNC;
				break;
			case 'a':
				/* Unload _all_ unused modules via NULL delete_module() call */
				/* until the number of modules does not change */
#ifdef CONFIG_FEATURE_QUERY_MODULE_INTERFACE
				buf = xmalloc(bufsize = 256);
#endif
				while (nmod != pnmod) {
					if (syscall(__NR_delete_module, NULL, flags) < 0) {
						if (errno==EFAULT)
							return(ret);
						bb_perror_msg_and_die("rmmod");
					}
					pnmod = nmod;
#ifdef CONFIG_FEATURE_QUERY_MODULE_INTERFACE
					/* 1 == QM_MODULES */
					if (my_query_module(NULL, 1, &buf, &bufsize, &nmod)) {
						bb_perror_msg_and_die("QM_MODULES");
					}
#endif
				}
#if defined CONFIG_FEATURE_CLEAN_UP && CONFIG_FEATURE_QUERY_MODULE_INTERFACE
				free(buf);
#endif
				return EXIT_SUCCESS;
			default:
				bb_show_usage();
		}
	}

	if (optind == argc)
		bb_show_usage();

	{
		for (n = optind; n < argc; n++) {
#ifdef CONFIG_FEATURE_2_6_MODULES
			char module_name[strlen(argv[n]) + 1];
			filename2modname(module_name, argv[n]);
#else
#define module_name		argv[n]
#endif
			if (syscall(__NR_delete_module, module_name, flags) < 0) {
				bb_perror_msg("%s", argv[n]);
				ret = EXIT_FAILURE;
			}
		}
	}

	return(ret);
}