/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "util.h"

struct {
	const char *opt;
	const char *notopt;
	unsigned long v;
} optnames[] = {
        { "remount",    NULL,           MS_REMOUNT     },
        { "ro",         "rw",           MS_RDONLY      },
        { "sync",       "async",        MS_SYNCHRONOUS },
        { "dirsync",    NULL,           MS_DIRSYNC     },
        { "nodev",      "dev",          MS_NODEV       },
        { "noatime",    "atime",        MS_NOATIME     },
        { "nodiratime", "diratime",     MS_NODIRATIME  },
        { "noexec",     "exec",         MS_NOEXEC      },
        { "nosuid",     "suid",         MS_NOSUID      },
        { "mand",       "nomand",       MS_MANDLOCK    },
        { "relatime",   "norelatime",   MS_RELATIME    },
        { NULL,         NULL,           0              }
};

static struct option {
	char *name;
	struct option *next;
} *opthead;

static void
usage(void)
{
	eprintf("usage: %s [-BMRadn] [-t fstype] [-o options] [source] [target]\n",
		argv0);
}

int
main(int argc, char *argv[])
{
	int i, validopt;
	int oflag = 0, aflag = 0;
	unsigned long flags = 0;
	char *types = NULL, *arg = NULL, *p;
	const char *source;
	const char *target;
	struct stat st1, st2;
	void *data = NULL;
	struct mntent *me = NULL;
	FILE *fp;
	struct option *opt, *tmp;

	ARGBEGIN {
	case 'B':
		flags |= MS_BIND;
		break;
	case 'M':
		flags |= MS_MOVE;
		break;
	case 'R':
		flags |= MS_REC;
		break;
	case 'a':
		aflag = 1;
		break;
	case 'd':
		data = EARGF(usage());
		break;
	case 'o':
		oflag = 1;
		arg = EARGF(usage());
		for (p = strtok(arg, ","); p; p = strtok(NULL, ",")) {
			opt = malloc(sizeof(*opt));
			if (!opt)
				eprintf("malloc:");
			opt->name = strdup(p);
			if (!opt->name)
				eprintf("strdup:");
			opt->next = opthead;
			opthead = opt;
		}
		break;
	case 't':
		types = EARGF(usage());
		break;
	case 'n':
		break;
	default:
		usage();
	} ARGEND;

	if (argc < 1 && aflag == 0)
		usage();

	for (opt = opthead; opt; opt = opt->next) {
		validopt = 0;
		for (i = 0; optnames[i].v; i++) {
			if (optnames[i].opt) {
				if (!strcmp(opt->name,
					    optnames[i].opt)) {
					flags |= optnames[i].v;
					validopt = 1;
					break;
				}
			}
			if (optnames[i].notopt) {
				if (!strcmp(opt->name,
					    optnames[i].notopt)) {
					flags &= ~optnames[i].v;
					validopt = 1;
					break;
				}
			}
		}
		if (!validopt)
			break;
	}
	if (oflag && !validopt)
		eprintf("unknown option: %s\n", opt->name);

	if (aflag == 1)
		goto domount;

	source = argv[0];
	target = argv[1];

	if (!target) {
		target = argv[0];
		source = NULL;
		if (stat(target, &st1) < 0)
			eprintf("stat %s:", target);
		fp = setmntent("/proc/mounts", "r");
		if (!fp)
			eprintf("setmntent %s:", "/proc/mounts");
		while ((me = getmntent(fp))) {
			if (stat(me->mnt_dir, &st2) < 0)
				eprintf("stat %s:", me->mnt_dir);
			if (st1.st_dev == st2.st_dev &&
			    st1.st_ino == st2.st_ino) {
				source = strdup(me->mnt_fsname);
				break;
			}
		}
		endmntent(fp);
		if (!source)
			eprintf("can't find %s mountpoint\n", target);
	}

	if (mount(source, target, types, flags, data) < 0)
		eprintf("mount:");

domount:
	if (aflag == 1) {
		fp = setmntent("/etc/fstab", "r");
		if (!fp)
			eprintf("setmntent %s:", "/etc/fstab");
		while ((me = getmntent(fp)))
			if (mount(me->mnt_fsname, me->mnt_dir, me->mnt_type,
				  0, me->mnt_opts) < 0)
				fprintf(stderr, "mount: %s\n", strerror(errno));
		endmntent(fp);
	}

	opt = opthead;
	while (opt) {
		tmp = opt->next;
		free(opt->name);
		free(opt);
		opt = tmp;
	}

	return EXIT_SUCCESS;
}