/*
 * Mount helper utility for Linux CIFS VFS (virtual filesystem) client
 * Copyright (C) 2003,2010 Steve French  (sfrench@us.ibm.com)
 * Copyright (C) 2008 Jeremy Allison (jra@samba.org)
 * Copyright (C) 2010 Jeff Layton (jlayton@samba.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 3 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, see <http://www.gnu.org/licenses/>.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <getopt.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <mntent.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <libgen.h>
#include <sys/mman.h>
#include <sys/wait.h>
#ifdef HAVE_SYS_FSUID_H
#include <sys/fsuid.h>
#endif /* HAVE_SYS_FSUID_H */
#ifdef HAVE_LIBCAP_NG
#include <cap-ng.h>
#else /* HAVE_LIBCAP_NG */
#ifdef HAVE_PRCTL
#include <sys/prctl.h>
#endif /* HAVE_PRCTL */
#ifdef HAVE_LIBCAP
#include <sys/capability.h>
#endif /* HAVE_LIBCAP */
#endif /* HAVE_LIBCAP_NG */
#include "mount.h"
#include "util.h"
#include "resolve_host.h"

#ifndef MS_MOVE 
#define MS_MOVE 8192 
#endif 

#ifndef MS_BIND
#define MS_BIND 4096
#endif

/* private flags - clear these before passing to kernel */
#define MS_USERS	0x40000000
#define MS_USER		0x80000000

#define MAX_UNC_LEN 1024

/* I believe that the kernel limits options data to a page */
#define MAX_OPTIONS_LEN	4096

/* max length of mtab options */
#define MTAB_OPTIONS_LEN 220

/*
 * Max share name, username, password and domain sizes match the kernel's
 * allowances for these string sizes which in turn match Microsoft's
 * documentation.
 */

/* Max length of the share name portion of a UNC. Share names over 80
 * characters cannot be accessed via commandline in Windows 2000/XP. */
#define MAX_SHARE_LEN 256

/* Max user name length. */
#define MAX_USERNAME_SIZE 256

/* Max domain size. */
#define MAX_DOMAIN_SIZE 256

/* Max password size. */
#define MOUNT_PASSWD_SIZE 512

/*
 * mount.cifs has been the subject of many "security" bugs that have arisen
 * because of users and distributions installing it as a setuid root program
 * before it had been audited for security holes. The default behavior is
 * now to allow mount.cifs to be run as a setuid root program. Some admins
 * may want to disable this fully, so this switch remains in place.
 */
#define CIFS_DISABLE_SETUID_CAPABILITY 0

/*
 * When an unprivileged user runs a setuid mount.cifs, we set certain mount
 * flags by default. These defaults can be changed here.
 */
#define CIFS_SETUID_FLAGS (MS_NOSUID|MS_NODEV)

/*
 * Values for parsing a credentials file.
 */
#define CRED_UNPARSEABLE 0
#define CRED_USER        1
#define CRED_PASS        2
#define CRED_DOM         4

/*
 * Values for parsing command line options.
 */
#define OPT_ERROR       -1
#define OPT_IGNORE      0
#define OPT_USERS       1
#define OPT_USER        2
#define OPT_USER_XATTR  3
#define OPT_PASS        4
#define OPT_SEC         5
#define OPT_IP          6
#define OPT_UNC         7
#define OPT_CRED        8
#define OPT_UID         9
#define OPT_GID        10
#define OPT_FMASK      11
#define OPT_FILE_MODE  12
#define OPT_DMASK      13
#define OPT_DIR_MODE   14
#define OPT_DOM        15
#define OPT_NO_SUID    16
#define OPT_SUID       17
#define OPT_NO_DEV     18
#define OPT_DEV        19
#define OPT_NO_LOCK    20
#define OPT_NO_EXEC    21
#define OPT_EXEC       22
#define OPT_GUEST      23
#define OPT_RO         24
#define OPT_RW         25
#define OPT_REMOUNT    26
#define OPT_MAND       27
#define OPT_NOMAND     28
#define OPT_CRUID      29
#define OPT_BKUPUID    30
#define OPT_BKUPGID    31
#define OPT_NOFAIL     32

#define MNT_TMP_FILE "/.mtab.cifs.XXXXXX"

/* struct for holding parsed mount info for use by privleged process */
struct parsed_mount_info {
	unsigned long flags;
	char host[NI_MAXHOST + 1];
	char share[MAX_SHARE_LEN + 1];
	char prefix[PATH_MAX + 1];
	char options[MAX_OPTIONS_LEN];
	char domain[MAX_DOMAIN_SIZE + 1];
	char username[MAX_USERNAME_SIZE + 1];
	char password[MOUNT_PASSWD_SIZE + 1];
	char addrlist[MAX_ADDR_LIST_LEN];
	unsigned int got_user:1;
	unsigned int got_password:1;
	unsigned int fakemnt:1;
	unsigned int nomtab:1;
	unsigned int verboseflag:1;
	unsigned int nofail:1;
	unsigned int got_domain:1;
};

static const char *thisprogram;
static const char *cifs_fstype = "cifs";

static int parse_unc(const char *unc_name, struct parsed_mount_info *parsed_info);

static int check_setuid(void)
{
	if (geteuid()) {
		fprintf(stderr, "This program is not installed setuid root - "
			" \"user\" CIFS mounts not supported.\n");
		return EX_USAGE;
	}

#if CIFS_DISABLE_SETUID_CAPABILITY
	if (getuid() && !geteuid()) {
		printf("This mount.cifs program has been built with the "
		       "ability to run as a setuid root program disabled.\n");
		return EX_USAGE;
	}
#endif /* CIFS_DISABLE_SETUID_CAPABILITY */

	return 0;
}

static int
check_fstab(const char *progname, const char *mountpoint, const char *devname,
	    char **options)
{
	FILE *fstab;
	struct mntent *mnt;

	/* make sure this mount is listed in /etc/fstab */
	fstab = setmntent(_PATH_MNTTAB, "r");
	if (!fstab) {
		fprintf(stderr, "Couldn't open %s for reading!\n", _PATH_MNTTAB);
		return EX_FILEIO;
	}

	while ((mnt = getmntent(fstab))) {
		if (!strcmp(mountpoint, mnt->mnt_dir))
			break;
	}
	endmntent(fstab);

	if (mnt == NULL || strcmp(mnt->mnt_fsname, devname)) {
		fprintf(stderr, "%s: permission denied: no match for "
			"%s found in %s\n", progname, mountpoint, _PATH_MNTTAB);
		return EX_USAGE;
	}

	/*
	 * 'mount' munges the options from fstab before passing them
	 * to us. It is non-trivial to test that we have the correct
	 * set of options. We don't want to trust what the user
	 * gave us, so just take whatever is in /etc/fstab.
	 */
	free(*options);
	*options = strdup(mnt->mnt_opts);
	return 0;
}

/* BB finish BB

	cifs_umount
	open nofollow - avoid symlink exposure? 
	get owner of dir see if matches self or if root
	call system(umount argv) etc.

BB end finish BB */

static int mount_usage(FILE * stream)
{
	fprintf(stream, "\nUsage:  %s <remotetarget> <dir> -o <options>\n",
		thisprogram);
	fprintf(stream, "\nMount the remote target, specified as a UNC name,");
	fprintf(stream, " to a local directory.\n\nOptions:\n");
	fprintf(stream, "\tuser=<arg>\n\tpass=<arg>\n\tdom=<arg>\n");
	fprintf(stream, "\nLess commonly used options:");
	fprintf(stream,
		"\n\tcredentials=<filename>,guest,perm,noperm,setuids,nosetuids,rw,ro,");
	fprintf(stream,
		"\n\tsep=<char>,iocharset=<codepage>,suid,nosuid,exec,noexec,serverino,");
	fprintf(stream,
		"\n\tmapchars,nomapchars,nolock,servernetbiosname=<SRV_RFC1001NAME>");
	fprintf(stream,
		"\n\tdirectio,nounix,cifsacl,sec=<authentication mechanism>,sign,seal,fsc");
	fprintf(stream,
		"\n\nOptions not needed for servers supporting CIFS Unix extensions");
	fprintf(stream,
		"\n\t(e.g. unneeded for mounts to most Samba versions):");
	fprintf(stream,
		"\n\tuid=<uid>,gid=<gid>,dir_mode=<mode>,file_mode=<mode>,sfu");
	fprintf(stream, "\n\nRarely used options:");
	fprintf(stream,
		"\n\tport=<tcpport>,rsize=<size>,wsize=<size>,unc=<unc_name>,ip=<ip_address>,");
	fprintf(stream,
		"\n\tdev,nodev,nouser_xattr,netbiosname=<OUR_RFC1001NAME>,hard,soft,intr,");
	fprintf(stream,
		"\n\tnointr,ignorecase,noposixpaths,noacl,prefixpath=<path>,nobrl");
	fprintf(stream,
		"\n\nOptions are described in more detail in the manual page");
	fprintf(stream, "\n\tman 8 mount.cifs\n");
	fprintf(stream, "\nTo display the version number of the mount helper:");
	fprintf(stream, "\n\t%s -V\n", thisprogram);

	if (stream == stderr)
		return EX_USAGE;
	return 0;
}

/*
 * CIFS has to "escape" commas in the password field so that they don't
 * end up getting confused for option delimiters. Copy password into pw
 * field, turning any commas into double commas.
 */
static int set_password(struct parsed_mount_info *parsed_info, const char *src)
{
	char *dst = parsed_info->password;
	unsigned int i = 0, j = 0;

	while (src[i]) {
		if (src[i] == ',')
			dst[j++] = ',';
		dst[j++] = src[i++];
		if (j > sizeof(parsed_info->password)) {
			fprintf(stderr, "Converted password too long!\n");
			return EX_USAGE;
		}
	}
	dst[j] = '\0';
	parsed_info->got_password = 1;
	return 0;
}

#ifdef HAVE_LIBCAP_NG
static int
drop_capabilities(int parent)
{
	capng_setpid(getpid());
	capng_clear(CAPNG_SELECT_BOTH);
	if (parent) {
		if (capng_updatev(CAPNG_ADD, CAPNG_PERMITTED, CAP_DAC_READ_SEARCH, CAP_DAC_OVERRIDE, -1)) {
			fprintf(stderr, "Unable to update capability set.\n");
			return EX_SYSERR;
		}
		if (capng_update(CAPNG_ADD, CAPNG_PERMITTED|CAPNG_EFFECTIVE, CAP_SYS_ADMIN)) {
			fprintf(stderr, "Unable to update capability set.\n");
			return EX_SYSERR;
		}
	} else {
		if (capng_update(CAPNG_ADD, CAPNG_PERMITTED, CAP_DAC_READ_SEARCH)) {
			fprintf(stderr, "Unable to update capability set.\n");
			return EX_SYSERR;
		}
	}
	if (capng_apply(CAPNG_SELECT_BOTH)) {
		fprintf(stderr, "Unable to apply new capability set.\n");
		return EX_SYSERR;
	}
	return 0;
}

static int
toggle_dac_capability(int writable, int enable)
{
	unsigned int capability = writable ? CAP_DAC_OVERRIDE : CAP_DAC_READ_SEARCH;

	if (capng_update(enable ? CAPNG_ADD : CAPNG_DROP, CAPNG_EFFECTIVE, capability)) {
		fprintf(stderr, "Unable to update capability set.\n");
		return EX_SYSERR;
	}
	if (capng_apply(CAPNG_SELECT_CAPS)) {
		fprintf(stderr, "Unable to apply new capability set.\n");
		return EX_SYSERR;
	}
	return 0;
}
#else /* HAVE_LIBCAP_NG */
#ifdef HAVE_LIBCAP
#ifdef HAVE_PRCTL
static int
prune_bounding_set(void)
{
	int i, rc = 0;
	static int bounding_set_cleared;

	if (bounding_set_cleared)
		return 0;

	for (i = 0; i <= CAP_LAST_CAP && rc == 0; ++i)
		rc = prctl(PR_CAPBSET_DROP, i);

	if (rc != 0) {
		fprintf(stderr, "Unable to clear capability bounding set: %d\n", rc);
		return EX_SYSERR;
	}

	++bounding_set_cleared;
	return 0;
}
#else /* HAVE_PRCTL */
static int
prune_bounding_set(void)
{
	return 0;
}
#endif /* HAVE_PRCTL */
static int
drop_capabilities(int parent)
{
	int rc, ncaps;
	cap_t caps;
	cap_value_t cap_list[3];

	rc = prune_bounding_set();
	if (rc)
		return rc;

	caps = cap_get_proc();
	if (caps == NULL) {
		fprintf(stderr, "Unable to get current capability set: %s\n",
			strerror(errno));
		return EX_SYSERR;
	}

	if (cap_clear(caps) == -1) {
		fprintf(stderr, "Unable to clear capability set: %s\n",
			strerror(errno));
		rc = EX_SYSERR;
		goto free_caps;
	}

	if (parent || getuid() == 0) {
		ncaps = 1;
		cap_list[0] = CAP_DAC_READ_SEARCH;
		if (parent) {
			cap_list[1] = CAP_DAC_OVERRIDE;
			cap_list[2] = CAP_SYS_ADMIN;
			ncaps += 2;
		}
		if (cap_set_flag(caps, CAP_PERMITTED, ncaps, cap_list, CAP_SET) == -1) {
			fprintf(stderr, "Unable to set permitted capabilities: %s\n",
				strerror(errno));
			rc = EX_SYSERR;
			goto free_caps;
		}
		if (parent) {
			cap_list[0] = CAP_SYS_ADMIN;
			if (cap_set_flag(caps, CAP_EFFECTIVE, 1, cap_list, CAP_SET) == -1) {
				fprintf(stderr, "Unable to set effective capabilities: %s\n",
					strerror(errno));
				rc = EX_SYSERR;
				goto free_caps;
			}
		}
	}

	if (cap_set_proc(caps) != 0) {
		fprintf(stderr, "Unable to set current process capabilities: %s\n",
			strerror(errno));
		rc = EX_SYSERR;
	}
free_caps:
	cap_free(caps);
	return rc;
}

static int
toggle_dac_capability(int writable, int enable)
{
	int rc = 0;
	cap_t caps;
	cap_value_t capability = writable ? CAP_DAC_OVERRIDE : CAP_DAC_READ_SEARCH;

	caps = cap_get_proc();
	if (caps == NULL) {
		fprintf(stderr, "Unable to get current capability set: %s\n",
			strerror(errno));
		return EX_SYSERR;
	}

	if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &capability,
			 enable ? CAP_SET : CAP_CLEAR) == -1) {
		fprintf(stderr, "Unable to %s effective capabilities: %s\n",
			enable ? "set" : "clear", strerror(errno));
		rc = EX_SYSERR;
		goto free_caps;
	}

	if (cap_set_proc(caps) != 0) {
		fprintf(stderr, "Unable to set current process capabilities: %s\n",
			strerror(errno));
		rc = EX_SYSERR;
	}
free_caps:
	cap_free(caps);
	return rc;
}
#else /* HAVE_LIBCAP */
static int
drop_capabilities(int parent __attribute((unused)))
{
	return 0;
}

static int
toggle_dac_capability(int writable __attribute((unused)), int enable __attribute((unused)))
{
	return 0;
}
#endif /* HAVE_LIBCAP */
#endif /* HAVE_LIBCAP_NG */

static void null_terminate_endl(char *source)
{
	char *newline = strchr(source, '\n');
	if (newline)
		*newline = '\0';
}

/*
 * Parse a line from the credentials file.  Changes target to first
 * character after '=' on 'line' and returns the value type of the line
 * Returns CRED_UNPARSEABLE on failure or if either parameter is NULL.
 */
static int parse_cred_line(char *line, char **target)
{
	if (line == NULL || target == NULL)
		goto parsing_err;

	/* position target at first char of value */
	*target = strchr(line, '=');
	if (!*target)
		goto parsing_err;
	*target += 1;

	/* tell the caller which value target points to */
	if (strncasecmp("user", line, 4) == 0)
		return CRED_USER;
	if (strncasecmp("pass", line, 4) == 0)
		return CRED_PASS;
	if (strncasecmp("dom", line, 3) == 0)
		return CRED_DOM;

parsing_err:
	return CRED_UNPARSEABLE;
}

static int open_cred_file(char *file_name,
			struct parsed_mount_info *parsed_info)
{
	char *line_buf = NULL;
	char *temp_val = NULL;
	FILE *fs = NULL;
	int i;
	const int line_buf_size = 4096;
	const int min_non_white = 10;

	i = toggle_dac_capability(0, 1);
	if (i)
		goto return_i;

	i = access(file_name, R_OK);
	if (i) {
		toggle_dac_capability(0, 0);
		i = errno;
		goto return_i;
	}

	fs = fopen(file_name, "r");
	if (fs == NULL) {
		toggle_dac_capability(0, 0);
		i = errno;
		goto return_i;
	}

	i = toggle_dac_capability(0, 0);
	if (i)
		goto return_i;

	line_buf = (char *)malloc(line_buf_size);
	if (line_buf == NULL) {
		i = EX_SYSERR;
		goto return_i;
	}

	/* parse line from credentials file */
	while (fgets(line_buf, line_buf_size, fs)) {
		/* eat leading white space */
		for (i = 0; i < line_buf_size - min_non_white + 1; i++) {
			if ((line_buf[i] != ' ') && (line_buf[i] != '\t'))
				break;
		}
		null_terminate_endl(line_buf);

		/* parse next token */
		switch (parse_cred_line(line_buf + i, &temp_val)) {
		case CRED_USER:
			strlcpy(parsed_info->username, temp_val,
				sizeof(parsed_info->username));
			parsed_info->got_user = 1;
			break;
		case CRED_PASS:
			i = set_password(parsed_info, temp_val);
			if (i)
				goto return_i;
			break;
		case CRED_DOM:
			if (parsed_info->verboseflag)
				fprintf(stderr, "domain=%s\n",
					temp_val);
			strlcpy(parsed_info->domain, temp_val,
				sizeof(parsed_info->domain));
			break;
		case CRED_UNPARSEABLE:
			if (parsed_info->verboseflag)
				fprintf(stderr, "Credential formatted "
					"incorrectly: %s\n",
					temp_val ? temp_val : "(null)");
			break;
		}
	}
	i = 0;
return_i:
	if (fs != NULL)
		fclose(fs);

	/* make sure passwords are scrubbed from memory */
	if (line_buf != NULL)
		memset(line_buf, 0, line_buf_size);
	free(line_buf);
	return i;
}

static int
get_password_from_file(int file_descript, char *filename,
		       struct parsed_mount_info *parsed_info)
{
	int rc = 0;
	char buf[sizeof(parsed_info->password) + 1];

	if (filename != NULL) {
		rc = toggle_dac_capability(0, 1);
		if (rc)
			return rc;

		rc = access(filename, R_OK);
		if (rc) {
			fprintf(stderr,
				"mount.cifs failed: access check of %s failed: %s\n",
				filename, strerror(errno));
			toggle_dac_capability(0, 0);
			return EX_SYSERR;
		}

		file_descript = open(filename, O_RDONLY);
		if (file_descript < 0) {
			fprintf(stderr,
				"mount.cifs failed. %s attempting to open password file %s\n",
				strerror(errno), filename);
			toggle_dac_capability(0, 0);
			return EX_SYSERR;
		}

		rc = toggle_dac_capability(0, 0);
		if (rc) {
			rc = EX_SYSERR;
			goto get_pw_exit;
		}
	}

	memset(buf, 0, sizeof(buf));
	rc = read(file_descript, buf, sizeof(buf) - 1);
	if (rc < 0) {
		fprintf(stderr,
			"mount.cifs failed. Error %s reading password file\n",
			strerror(errno));
		rc = EX_SYSERR;
		goto get_pw_exit;
	}

	rc = set_password(parsed_info, buf);

get_pw_exit:
	if (filename != NULL)
		close(file_descript);
	return rc;
}

/*
 * Returns OPT_ERROR on unparsable token.
 */
static int parse_opt_token(const char *token)
{
	if (token == NULL)
		return OPT_ERROR;

	/*
	 * token is NULL terminated and contains exactly the
	 * keyword so we can match exactly
	 */
	if (strcmp(token, "users") == 0)
		return OPT_USERS;
	if (strcmp(token, "user_xattr") == 0)
		return OPT_USER_XATTR;
	if (strcmp(token, "user") == 0 ||
		strcmp(token, "username") == 0)
		return OPT_USER;
	if (strcmp(token, "pass") == 0 ||
		strcmp(token, "password") == 0)
		return OPT_PASS;
	if (strcmp(token, "sec") == 0)
		return OPT_SEC;
	if (strcmp(token, "ip") == 0 ||
		strcmp(token, "addr") == 0)
		return OPT_IP;
	if (strcmp(token, "unc") == 0 ||
		strcmp(token, "target") == 0 ||
		strcmp(token, "path") == 0)
		return OPT_UNC;
	if (strcmp(token, "dom") == 0 ||
		strcmp(token, "domain") == 0 ||
		strcmp(token, "workgroup") == 0)
		return OPT_DOM;
	if (strcmp(token, "cred") == 0 || /* undocumented */
		strcmp(token, "credentials") == 0)
		return OPT_CRED;
	if (strcmp(token, "uid") == 0)
		return OPT_UID;
	if (strcmp(token, "cruid") == 0)
		return OPT_CRUID;
	if (strcmp(token, "gid") == 0)
		return OPT_GID;
	if (strcmp(token, "fmask") == 0)
		return OPT_FMASK;
	if (strcmp(token, "file_mode") == 0)
		return OPT_FILE_MODE;
	if (strcmp(token, "dmask") == 0)
		return OPT_DMASK;
	if (strcmp(token, "dir_mode") == 0 ||
		strcmp(token, "dirm") == 0)
		return OPT_DIR_MODE;
	if (strcmp(token, "nosuid") == 0)
		return OPT_NO_SUID;
	if (strcmp(token, "suid") == 0)
		return OPT_SUID;
	if (strcmp(token, "nodev") == 0)
		return OPT_NO_DEV;
	if (strcmp(token, "nobrl") == 0 ||
		strcmp(token, "nolock") == 0)
		return OPT_NO_LOCK;
	if (strcmp(token, "mand") == 0)
		return OPT_MAND;
	if (strcmp(token, "nomand") == 0)
		return OPT_NOMAND;
	if (strcmp(token, "dev") == 0)
		return OPT_DEV;
	if (strcmp(token, "noexec") == 0)
		return OPT_NO_EXEC;
	if (strcmp(token, "exec") == 0)
		return OPT_EXEC;
	if (strcmp(token, "guest") == 0)
		return OPT_GUEST;
	if (strcmp(token, "ro") == 0)
		return OPT_RO;
	if (strcmp(token, "rw") == 0)
		return OPT_RW;
	if (strcmp(token, "remount") == 0)
		return OPT_REMOUNT;
	if (strcmp(token, "_netdev") == 0)
		return OPT_IGNORE;
	if (strcmp(token, "backupuid") == 0)
		return OPT_BKUPUID;
	if (strcmp(token, "backupgid") == 0)
		return OPT_BKUPGID;
	if (strcmp(token, "nofail") == 0)
		return OPT_NOFAIL;
	if (strncmp(token, "x-", 2) == 0)
		return OPT_IGNORE;

	return OPT_ERROR;
}

static int
parse_options(const char *data, struct parsed_mount_info *parsed_info)
{
	char *value = NULL;
	char *equals = NULL;
	char *next_keyword = NULL;
	char *out = parsed_info->options;
	unsigned long *filesys_flags = &parsed_info->flags;
	int out_len = 0;
	int word_len;
	int rc = 0;
	int got_bkupuid = 0;
	int got_bkupgid = 0;
	int got_uid = 0;
	int got_cruid = 0;
	int got_gid = 0;
	uid_t uid, cruid = 0, bkupuid = 0;
	gid_t gid, bkupgid = 0;
	char *ep;
	struct passwd *pw;
	struct group *gr;
	/*
	 * max 32-bit uint in decimal is 4294967295 which is 10 chars wide
	 * +1 for NULL, and +1 for good measure
	 */
	char txtbuf[12];

	/* make sure we're starting from beginning */
	out[0] = '\0';

	/* BB fixme check for separator override BB */
	uid = getuid();
	if (uid != 0)
		got_uid = 1;

	gid = getgid();
	if (gid != 0)
		got_gid = 1;

	if (!data)
		return EX_USAGE;

	/*
	 * format is keyword,keyword2=value2,keyword3=value3... 
	 * data  = next keyword
	 * value = next value ie stuff after equal sign
	 */
	while (data && *data) {
		next_keyword = strchr(data, ',');	/* BB handle sep= */

		/* temporarily null terminate end of keyword=value pair */
		if (next_keyword)
			*next_keyword++ = 0;

		/* temporarily null terminate keyword if there's a value */
		value = NULL;
		if ((equals = strchr(data, '=')) != NULL) {
			*equals = '\0';
			value = equals + 1;
		}

		switch(parse_opt_token(data)) {
		case OPT_USERS:
			if (!value || !*value) {
				*filesys_flags |= MS_USERS;
				goto nocopy;
			}
			break;

		case OPT_USER:
			if (!value || !*value) {
				if (data[4] == '\0') {
					*filesys_flags |= MS_USER;
					goto nocopy;
				} else {
					fprintf(stderr,
						"username specified with no parameter\n");
					return EX_USAGE;
				}
			} else {
				strlcpy(parsed_info->username, value,
					sizeof(parsed_info->username));
				parsed_info->got_user = 1;
				goto nocopy;
			}

		case OPT_PASS:
			if (parsed_info->got_password) {
				fprintf(stderr,
					"password specified twice, ignoring second\n");
				goto nocopy;
			}
			if (!value || !*value) {
				parsed_info->got_password = 1;
				goto nocopy;
			}
			rc = set_password(parsed_info, value);
			if (rc)
				return rc;
			goto nocopy;

		case OPT_SEC:
			if (value) {
				if (!strncmp(value, "none", 4) ||
				    !strncmp(value, "krb5", 4))
					parsed_info->got_password = 1;
			}
			break;

		case OPT_IP:
			if (!value || !*value) {
				fprintf(stderr,
					"target ip address argument missing\n");
			} else if (strnlen(value, MAX_ADDRESS_LEN) <=
				MAX_ADDRESS_LEN) {
				strcpy(parsed_info->addrlist, value);
				if (parsed_info->verboseflag)
					fprintf(stderr,
						"ip address %s override specified\n",
						value);
				goto nocopy;
			} else {
				fprintf(stderr, "ip address too long\n");
				return EX_USAGE;

			}
			break;

		/* unc || target || path */
		case OPT_UNC:
			if (!value || !*value) {
				fprintf(stderr,
					"invalid path to network resource\n");
				return EX_USAGE;
			}
			rc = parse_unc(value, parsed_info);
			if (rc)
				return rc;
			break;

		/* dom || workgroup */
		case OPT_DOM:
			if (!value) {
				/*
				 * An empty domain has been passed
				 */
				/* not necessary but better safe than.. */
				parsed_info->domain[0] = '\0';
				parsed_info->got_domain = 1;
				goto nocopy;
			}
			if (strnlen(value, sizeof(parsed_info->domain)) >=
			    sizeof(parsed_info->domain)) {
				fprintf(stderr, "domain name too long\n");
				return EX_USAGE;
			}
			strlcpy(parsed_info->domain, value,
				sizeof(parsed_info->domain));
			goto nocopy;

		case OPT_CRED:
			if (!value || !*value) {
				fprintf(stderr,
					"invalid credential file name specified\n");
				return EX_USAGE;
			}
			rc = open_cred_file(value, parsed_info);
			if (rc) {
				fprintf(stderr,
					"error %d (%s) opening credential file %s\n",
					rc, strerror(rc), value);
				return rc;
			}
			goto nocopy;

		case OPT_UID:
			if (!value || !*value)
				goto nocopy;

			got_uid = 1;
			pw = getpwnam(value);
			if (pw) {
				uid = pw->pw_uid;
				goto nocopy;
			}

			errno = 0;
			uid = strtoul(value, &ep, 10);
			if (errno == 0 && *ep == '\0')
				goto nocopy;

			fprintf(stderr, "bad option uid=\"%s\"\n", value);
			return EX_USAGE;
		case OPT_CRUID:
			if (!value || !*value)
				goto nocopy;

			got_cruid = 1;
			pw = getpwnam(value);
			if (pw) {
				cruid = pw->pw_uid;
				goto nocopy;
			}

			errno = 0;
			cruid = strtoul(value, &ep, 10);
			if (errno == 0 && *ep == '\0')
				goto nocopy;

			fprintf(stderr, "bad option: cruid=\"%s\"\n", value);
			return EX_USAGE;
		case OPT_GID:
			if (!value || !*value)
				goto nocopy;

			got_gid = 1;
			gr = getgrnam(value);
			if (gr) {
				gid = gr->gr_gid;
				goto nocopy;
			}

			errno = 0;
			gid = strtoul(value, &ep, 10);
			if (errno == 0 && *ep == '\0')
				goto nocopy;

			fprintf(stderr, "bad option: gid=\"%s\"\n", value);
			return EX_USAGE;
		/* fmask falls through to file_mode */
		case OPT_FMASK:
			fprintf(stderr,
				"WARNING: CIFS mount option 'fmask' is\
				 deprecated. Use 'file_mode' instead.\n");
			data = "file_mode";	/* BB fix this */
			/* Fallthrough */
		case OPT_FILE_MODE:
			if (!value || !*value) {
				fprintf(stderr,
					"Option '%s' requires a numerical argument\n",
					data);
				return EX_USAGE;
			}

			if (value[0] != '0')
				fprintf(stderr,
					"WARNING: '%s' not expressed in octal.\n",
					data);
			break;

		/* dmask falls through to dir_mode */
		case OPT_DMASK:
			fprintf(stderr,
				"WARNING: CIFS mount option 'dmask' is\
				 deprecated. Use 'dir_mode' instead.\n");
			data = "dir_mode";
			/* Fallthrough */
		case OPT_DIR_MODE:
			if (!value || !*value) {
				fprintf(stderr,
					"Option '%s' requires a numerical argument\n",
					data);
				return EX_USAGE;
			}

			if (value[0] != '0')
				fprintf(stderr,
					"WARNING: '%s' not expressed in octal.\n",
					data);
			break;
		case OPT_NO_SUID:
			*filesys_flags |= MS_NOSUID;
			goto nocopy;
		case OPT_SUID:
			*filesys_flags &= ~MS_NOSUID;
			goto nocopy;
		case OPT_NO_DEV:
			*filesys_flags |= MS_NODEV;
			goto nocopy;
		case OPT_NO_LOCK:
			*filesys_flags &= ~MS_MANDLOCK;
			break;
		case OPT_MAND:
			*filesys_flags |= MS_MANDLOCK;
			goto nocopy;
		case OPT_NOMAND:
			*filesys_flags &= ~MS_MANDLOCK;
			goto nocopy;
		case OPT_DEV:
			*filesys_flags &= ~MS_NODEV;
			goto nocopy;
		case OPT_NO_EXEC:
			*filesys_flags |= MS_NOEXEC;
			goto nocopy;
		case OPT_EXEC:
			*filesys_flags &= ~MS_NOEXEC;
			goto nocopy;
		case OPT_GUEST:
			parsed_info->got_user = 1;
			parsed_info->got_password = 1;
			goto nocopy;
		case OPT_RO:
			*filesys_flags |= MS_RDONLY;
			goto nocopy;
		case OPT_RW:
			*filesys_flags &= ~MS_RDONLY;
			goto nocopy;
		case OPT_REMOUNT:
			*filesys_flags |= MS_REMOUNT;
			goto nocopy;
		case OPT_IGNORE:
			goto nocopy;
		case OPT_BKUPUID:
			if (!value || !*value)
				goto nocopy;

			got_bkupuid = 1;
			errno = 0;
			bkupuid = strtoul(value, &ep, 10);
			if (errno == 0 && *ep == '\0')
				goto nocopy;

			pw = getpwnam(value);
			if (pw == NULL) {
				fprintf(stderr,
					"bad user name \"%s\"\n", value);
				return EX_USAGE;
			}

			bkupuid = pw->pw_uid;
			goto nocopy;
		case OPT_BKUPGID:
			if (!value || !*value)
				goto nocopy;

			got_bkupgid = 1;
			errno = 0;
			bkupgid = strtoul(value, &ep, 10);
			if (errno == 0 && *ep == '\0')
				goto nocopy;

			gr = getgrnam(value);
			if (gr == NULL) {
				fprintf(stderr,
					"bad group name \"%s\"\n", value);
				return EX_USAGE;
			}

			bkupgid = gr->gr_gid;
			goto nocopy;
		case OPT_NOFAIL:
			parsed_info->nofail = 1;
			goto nocopy;
		}

		/* check size before copying option to buffer */
		word_len = strlen(data);
		if (value)
			word_len += 1 + strlen(value);

		/* need 2 extra bytes for comma and null byte */
		if (out_len + word_len + 2 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		/* put back equals sign, if any */
		if (equals)
			*equals = '=';

		/* go ahead and copy */
		if (out_len)
			strlcat(out, ",", MAX_OPTIONS_LEN);

		strlcat(out, data, MAX_OPTIONS_LEN);
		out_len = strlen(out);
nocopy:
		data = next_keyword;
	}


	/* special-case the uid and gid */
	if (got_uid) {
		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", uid);

		/* comma + "uid=" + terminating NULL == 6 */
		if (out_len + word_len + 6 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		if (out_len) {
			strlcat(out, ",", MAX_OPTIONS_LEN);
			out_len++;
		}
		snprintf(out + out_len, word_len + 5, "uid=%s", txtbuf);
		out_len = strlen(out);
	}
	if (got_cruid) {
		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", cruid);

		/* comma + "cruid=" + terminating NULL == 8 */
		if (out_len + word_len + 8 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		if (out_len) {
			strlcat(out, ",", MAX_OPTIONS_LEN);
			out_len++;
		}
		snprintf(out + out_len, word_len + 7, "cruid=%s", txtbuf);
		out_len = strlen(out);
	}
	if (got_gid) {
		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", gid);

		/* comma + "gid=" + terminating NULL == 6 */
		if (out_len + word_len + 6 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		if (out_len) {
			strlcat(out, ",", MAX_OPTIONS_LEN);
			out_len++;
		}
		snprintf(out + out_len, word_len + 5, "gid=%s", txtbuf);
	}
	if (got_bkupuid) {
		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", bkupuid);

		/* comma + "backupuid=" + terminating NULL == 12 */
		if (out_len + word_len + 12 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		if (out_len) {
			strlcat(out, ",", MAX_OPTIONS_LEN);
			out_len++;
		}
		snprintf(out + out_len, word_len + 11, "backupuid=%s", txtbuf);
		out_len = strlen(out);
	}
	if (got_bkupgid) {
		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", bkupgid);

		/* comma + "backkupgid=" + terminating NULL == 12 */
		if (out_len + word_len + 12 > MAX_OPTIONS_LEN) {
			fprintf(stderr, "Options string too long\n");
			return EX_USAGE;
		}

		if (out_len) {
			strlcat(out, ",", MAX_OPTIONS_LEN);
			out_len++;
		}
		snprintf(out + out_len, word_len + 11, "backupgid=%s", txtbuf);
	}

	return 0;
}

static int parse_unc(const char *unc_name, struct parsed_mount_info *parsed_info)
{
	int length = strnlen(unc_name, MAX_UNC_LEN);
	const char *host, *share, *prepath;
	size_t hostlen, sharelen, prepathlen;

	if (length > (MAX_UNC_LEN - 1)) {
		fprintf(stderr, "mount error: UNC name too long\n");
		return EX_USAGE;
	}

	if (length < 3) {
		fprintf(stderr, "mount error: UNC name too short\n");
		return EX_USAGE;
	}

	if ((strncasecmp("cifs://", unc_name, 7) == 0) ||
	    (strncasecmp("smb://", unc_name, 6) == 0)) {
		fprintf(stderr,
			"Mounting cifs URL not implemented yet. Attempt to mount %s\n",
			unc_name);
		return EX_USAGE;
	}

	if (strncmp(unc_name, "//", 2) && strncmp(unc_name, "\\\\", 2)) {
		fprintf(stderr, "mount.cifs: bad UNC (%s)\n", unc_name);
		return EX_USAGE;
	}

	host = unc_name + 2;
	hostlen = strcspn(host, "/\\");
	if (!hostlen) {
		fprintf(stderr, "mount.cifs: bad UNC (%s)\n", unc_name);
		return EX_USAGE;
	}
	share = host + hostlen + 1;

	if (hostlen + 1 > sizeof(parsed_info->host)) {
		fprintf(stderr, "mount.cifs: host portion of UNC too long\n");
		return EX_USAGE;
	}

	sharelen = strcspn(share, "/\\");
	if (sharelen + 1 > sizeof(parsed_info->share)) {
		fprintf(stderr, "mount.cifs: share portion of UNC too long\n");
		return EX_USAGE;
	}

	prepath = share + sharelen;
	if (*prepath != '\0')
		prepath++;

	prepathlen = strlen(prepath);

	if (prepathlen + 1 > sizeof(parsed_info->prefix)) {
		fprintf(stderr, "mount.cifs: UNC prefixpath too long\n");
		return EX_USAGE;
	}

	/* copy pieces into their resepective buffers */
	memcpy(parsed_info->host, host, hostlen);
	memcpy(parsed_info->share, share, sharelen);
	memcpy(parsed_info->prefix, prepath, prepathlen);

	return 0;
}

static int get_pw_from_env(struct parsed_mount_info *parsed_info)
{
	int rc = 0;

	if (getenv("PASSWD"))
		rc = set_password(parsed_info, getenv("PASSWD"));
	else if (getenv("PASSWD_FD"))
		rc = get_password_from_file(atoi(getenv("PASSWD_FD")), NULL,
					    parsed_info);
	else if (getenv("PASSWD_FILE"))
		rc = get_password_from_file(0, getenv("PASSWD_FILE"),
					    parsed_info);

	return rc;
}

static struct option longopts[] = {
	{"all", 0, NULL, 'a'},
	{"help", 0, NULL, 'h'},
	{"move", 0, NULL, 'm'},
	{"bind", 0, NULL, 'b'},
	{"read-only", 0, NULL, 'r'},
	{"ro", 0, NULL, 'r'},
	{"verbose", 0, NULL, 'v'},
	{"version", 0, NULL, 'V'},
	{"read-write", 0, NULL, 'w'},
	{"rw", 0, NULL, 'w'},
	{"options", 1, NULL, 'o'},
	{"type", 1, NULL, 't'},
	{"uid", 1, NULL, '1'},
	{"gid", 1, NULL, '2'},
	{"user", 1, NULL, 'u'},
	{"username", 1, NULL, 'u'},
	{"dom", 1, NULL, 'd'},
	{"domain", 1, NULL, 'd'},
	{"password", 1, NULL, 'p'},
	{"pass", 1, NULL, 'p'},
	{"credentials", 1, NULL, 'c'},
	{"port", 1, NULL, 'P'},
	{"sloppy", 0, NULL, 's'},
	{NULL, 0, NULL, 0}
};

/* convert a string to uppercase. return false if the string
 * wasn't ASCII. Return success on a NULL ptr */
static int uppercase_string(char *string)
{
	if (!string)
		return 1;

	while (*string) {
		/* check for unicode */
		if ((unsigned char)string[0] & 0x80)
			return 0;
		*string = toupper((unsigned char)*string);
		string++;
	}

	return 1;
}

static void print_cifs_mount_version(void)
{
	printf("mount.cifs version: %s\n", VERSION);
}

/*
 * This function borrowed from fuse-utils...
 *
 * glibc's addmntent (at least as of 2.10 or so) doesn't properly encode
 * newlines embedded within the text fields. To make sure no one corrupts
 * the mtab, fail the mount if there are embedded newlines.
 */
static int check_newline(const char *progname, const char *name)
{
	const char *s;
	for (s = "\n"; *s; s++) {
		if (strchr(name, *s)) {
			fprintf(stderr,
				"%s: illegal character 0x%02x in mount entry\n",
				progname, *s);
			return EX_USAGE;
		}
	}
	return 0;
}

static int check_mtab(const char *progname, const char *devname,
		      const char *dir)
{
	if (check_newline(progname, devname) || check_newline(progname, dir))
		return EX_USAGE;
	return 0;
}

static int
add_mtab(char *devname, char *mountpoint, unsigned long flags, const char *fstype)
{
	int rc = 0, tmprc, fd;
	uid_t uid;
	char *mount_user = NULL;
	struct mntent mountent;
	struct stat statbuf;
	FILE *pmntfile;
	sigset_t mask, oldmask;

	uid = getuid();
	if (uid != 0)
		mount_user = getusername(uid);

	/*
	 * Set the real uid to the effective uid. This prevents unprivileged
	 * users from sending signals to this process, though ^c on controlling
	 * terminal should still work.
	 */
	rc = setreuid(geteuid(), -1);
	if (rc != 0) {
		fprintf(stderr, "Unable to set real uid to effective uid: %s\n",
				strerror(errno));
		return EX_FILEIO;
	}

	rc = sigfillset(&mask);
	if (rc) {
		fprintf(stderr, "Unable to set filled signal mask\n");
		return EX_FILEIO;
	}

	rc = sigprocmask(SIG_SETMASK, &mask, &oldmask);
	if (rc) {
		fprintf(stderr, "Unable to make process ignore signals\n");
		return EX_FILEIO;
	}

	rc = toggle_dac_capability(1, 1);
	if (rc)
		return EX_FILEIO;

	atexit(unlock_mtab);
	rc = lock_mtab();
	if (rc) {
		fprintf(stderr, "cannot lock mtab");
		rc = EX_FILEIO;
		goto add_mtab_exit;
	}

	pmntfile = setmntent(MOUNTED, "a+");
	if (!pmntfile) {
		fprintf(stderr, "could not update mount table\n");
		unlock_mtab();
		rc = EX_FILEIO;
		goto add_mtab_exit;
	}

	fd = fileno(pmntfile);
	if (fd < 0) {
		fprintf(stderr, "mntent does not appear to be valid\n");
		unlock_mtab();
		rc = EX_FILEIO;
		goto add_mtab_exit;
	}

	rc = fstat(fd, &statbuf);
	if (rc != 0) {
		fprintf(stderr, "unable to fstat open mtab\n");
		endmntent(pmntfile);
		unlock_mtab();
		rc = EX_FILEIO;
		goto add_mtab_exit;
	}

	mountent.mnt_fsname = devname;
	mountent.mnt_dir = mountpoint;
	mountent.mnt_type = (char *)(void *)fstype;
	mountent.mnt_opts = (char *)calloc(MTAB_OPTIONS_LEN, 1);
	if (mountent.mnt_opts) {
		if (flags & MS_RDONLY)
			strlcat(mountent.mnt_opts, "ro", MTAB_OPTIONS_LEN);
		else
			strlcat(mountent.mnt_opts, "rw", MTAB_OPTIONS_LEN);

		if (flags & MS_MANDLOCK)
			strlcat(mountent.mnt_opts, ",mand", MTAB_OPTIONS_LEN);
		if (flags & MS_NOEXEC)
			strlcat(mountent.mnt_opts, ",noexec", MTAB_OPTIONS_LEN);
		if (flags & MS_NOSUID)
			strlcat(mountent.mnt_opts, ",nosuid", MTAB_OPTIONS_LEN);
		if (flags & MS_NODEV)
			strlcat(mountent.mnt_opts, ",nodev", MTAB_OPTIONS_LEN);
		if (flags & MS_SYNCHRONOUS)
			strlcat(mountent.mnt_opts, ",sync", MTAB_OPTIONS_LEN);
		if (mount_user) {
			strlcat(mountent.mnt_opts, ",user=", MTAB_OPTIONS_LEN);
			strlcat(mountent.mnt_opts, mount_user,
				MTAB_OPTIONS_LEN);
		}
	}
	mountent.mnt_freq = 0;
	mountent.mnt_passno = 0;
	rc = addmntent(pmntfile, &mountent);
	if (rc) {
		int ignore __attribute__((unused));

		fprintf(stderr, "unable to add mount entry to mtab\n");
		ignore = ftruncate(fd, statbuf.st_size);
		rc = EX_FILEIO;
	}
	tmprc = my_endmntent(pmntfile, statbuf.st_size);
	if (tmprc) {
		fprintf(stderr, "error %d detected on close of mtab\n", tmprc);
		rc = EX_FILEIO;
	}
	unlock_mtab();
	free(mountent.mnt_opts);
add_mtab_exit:
	toggle_dac_capability(1, 0);
	sigprocmask(SIG_SETMASK, &oldmask, NULL);

	return rc;
}

static int
del_mtab(char *mountpoint)
{
	int len, tmprc, rc = 0;
	FILE *mnttmp, *mntmtab;
	struct mntent *mountent;
	char *mtabfile, *mtabdir, *mtabtmpfile = NULL;

	mtabfile = strdup(MOUNTED);
	if (!mtabfile) {
		fprintf(stderr, "del_mtab: cannot strdup MOUNTED\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	mtabdir = dirname(mtabfile);
	len = strlen(mtabdir) + strlen(MNT_TMP_FILE);
	mtabtmpfile = malloc(len + 1);
	if (!mtabtmpfile) {
		fprintf(stderr, "del_mtab: cannot allocate memory to tmp file\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	if (sprintf(mtabtmpfile, "%s%s", mtabdir, MNT_TMP_FILE) != len) {
		fprintf(stderr, "del_mtab: error writing new string\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	atexit(unlock_mtab);
	rc = lock_mtab();
	if (rc) {
		fprintf(stderr, "del_mtab: cannot lock mtab\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	mtabtmpfile = mktemp(mtabtmpfile);
	if (!mtabtmpfile) {
		fprintf(stderr, "del_mtab: cannot setup tmp file destination\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	mntmtab = setmntent(MOUNTED, "r");
	if (!mntmtab) {
		fprintf(stderr, "del_mtab: could not update mount table\n");
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	mnttmp = setmntent(mtabtmpfile, "w");
	if (!mnttmp) {
		fprintf(stderr, "del_mtab: could not update mount table\n");
		endmntent(mntmtab);
		rc = EX_FILEIO;
		goto del_mtab_exit;
	}

	while ((mountent = getmntent(mntmtab)) != NULL) {
		if (!strcmp(mountent->mnt_dir, mountpoint))
			continue;
		rc = addmntent(mnttmp, mountent);
		if (rc) {
			fprintf(stderr, "del_mtab: unable to add mount entry to mtab\n");
			rc = EX_FILEIO;
			goto del_mtab_error;
		}
	}

	endmntent(mntmtab);

	tmprc = my_endmntent(mnttmp, 0);
	if (tmprc) {
		fprintf(stderr, "del_mtab: error %d detected on close of tmp file\n", tmprc);
		rc = EX_FILEIO;
		goto del_mtab_error;
	}

	if (rename(mtabtmpfile, MOUNTED)) {
		fprintf(stderr, "del_mtab: error %d when renaming mtab in place\n", errno);
		rc = EX_FILEIO;
		goto del_mtab_error;
	}

del_mtab_exit:
	unlock_mtab();
	free(mtabtmpfile);
	free(mtabfile);
	return rc;

del_mtab_error:
	if (unlink(mtabtmpfile))
		fprintf(stderr, "del_mtab: failed to delete tmp file - %s\n",
				strerror(errno));
	goto del_mtab_exit;
}

/* have the child drop root privileges */
static int
drop_child_privs(void)
{
	int rc;
	uid_t uid = getuid();
	gid_t gid = getgid();

	if (gid) {
		rc = setgid(gid);
		if (rc) {
			fprintf(stderr, "Unable set group identity: %s\n",
					strerror(errno));
			return EX_SYSERR;
		}
	}
	if (uid) {
		rc = setuid(uid);
		if (rc) {
			fprintf(stderr, "Unable set user identity: %s\n",
					strerror(errno));
			return EX_SYSERR;
		}
	}

	return 0;
}

/*
 * If systemd is running and systemd-ask-password --
 * is available, then use that else fallback on getpass(..)
 *
 * Returns: @input or NULL on error
 */
static char*
get_password(const char *prompt, char *input, int capacity)
{
#ifdef ENABLE_SYSTEMD
	int is_systemd_running;
	struct stat a, b;

	/* We simply test whether the systemd cgroup hierarchy is
	 * mounted */
	is_systemd_running = (lstat("/sys/fs/cgroup", &a) == 0)
		&& (lstat("/sys/fs/cgroup/systemd", &b) == 0)
		&& (a.st_dev != b.st_dev);

	if (is_systemd_running) {
		char *cmd, *ret;
		FILE *ask_pass_fp = NULL;

		cmd = ret = NULL;
		if (asprintf(&cmd, "systemd-ask-password \"%s\"", prompt) >= 0) {
			ask_pass_fp = popen (cmd, "re");
			free (cmd);
		}

		if (ask_pass_fp) {
			ret = fgets(input, capacity, ask_pass_fp);
			pclose(ask_pass_fp);
		}

		if (ret) {
			int len = strlen(input);
			if (input[len - 1] == '\n')
				input[len - 1] = '\0';
			return input;
		}
	}
#endif

	/*
	 * Falling back to getpass(..)
	 * getpass is obsolete, but there's apparently nothing that replaces it
	 */
	char *tmp_pass = getpass(prompt);
	if (!tmp_pass)
		return NULL;

	strncpy(input, tmp_pass, capacity - 1);
	input[capacity - 1] = '\0';

	/* zero-out the static buffer */
	memset(tmp_pass, 0, strlen(tmp_pass));

	return input;
}

static int
assemble_mountinfo(struct parsed_mount_info *parsed_info,
		   const char *thisprogram, const char *mountpoint,
		   const char *orig_dev, char *orgoptions)
{
	int rc;

	rc = drop_capabilities(0);
	if (rc)
		goto assemble_exit;

	rc = drop_child_privs();
	if (rc)
		goto assemble_exit;

	if (getuid()) {
		rc = check_fstab(thisprogram, mountpoint, orig_dev,
				 &orgoptions);
		if (rc)
			goto assemble_exit;

		/* enable any default user mount flags */
		parsed_info->flags |= CIFS_SETUID_FLAGS;
	}

	rc = get_pw_from_env(parsed_info);
	if (rc)
		goto assemble_exit;

	if (orgoptions) {
		rc = parse_options(orgoptions, parsed_info);
		if (rc)
			goto assemble_exit;
	}

	if (getuid()) {
		if (!(parsed_info->flags & (MS_USERS | MS_USER))) {
			fprintf(stderr, "%s: permission denied\n", thisprogram);
			rc = EX_USAGE;
			goto assemble_exit;
		}
	}

	parsed_info->flags &= ~(MS_USERS | MS_USER);

	rc = parse_unc(orig_dev, parsed_info);
	if (rc)
		goto assemble_exit;

	if (parsed_info->addrlist[0] == '\0')
		rc = resolve_host(parsed_info->host, parsed_info->addrlist);

	switch (rc) {
	case EX_USAGE:
		fprintf(stderr, "mount error: could not resolve address for "
			"%s: %s\n", parsed_info->host,
			rc == EAI_SYSTEM ? strerror(errno) : gai_strerror(rc));
		goto assemble_exit;

	case EX_SYSERR:
		fprintf(stderr, "mount error: problem parsing address "
			"list: %s\n", strerror(errno));
		goto assemble_exit;
	}

	if (!parsed_info->got_user) {
		/*
		 * Note that the password will not be retrieved from the
		 * USER env variable (ie user%password form) as there is
		 * already a PASSWD environment varaible
		 */
		if (getenv("USER"))
			strlcpy(parsed_info->username, getenv("USER"),
				sizeof(parsed_info->username));
		else
			strlcpy(parsed_info->username, getusername(getuid()),
				sizeof(parsed_info->username));
		parsed_info->got_user = 1;
	}

	if (!parsed_info->got_password) {
		char tmp_pass[MOUNT_PASSWD_SIZE + 1];
		char *prompt = NULL;

		if(asprintf(&prompt, "Password for %s@%s: ", parsed_info->username, orig_dev) < 0)
			prompt = NULL;

		if (get_password(prompt ? prompt : "Password: ", tmp_pass, MOUNT_PASSWD_SIZE + 1)) {
			rc = set_password(parsed_info, tmp_pass);
		} else {
			fprintf(stderr, "Error reading password, exiting\n");
			rc = EX_SYSERR;
		}

		free(prompt);
		if (rc)
			goto assemble_exit;
	}

	/* copy in user= string */
	if (parsed_info->got_user) {
		if (*parsed_info->options)
			strlcat(parsed_info->options, ",",
				sizeof(parsed_info->options));
		strlcat(parsed_info->options, "user=",
			sizeof(parsed_info->options));
		strlcat(parsed_info->options, parsed_info->username,
			sizeof(parsed_info->options));
	}

	if (*parsed_info->domain) {
		if (*parsed_info->options)
			strlcat(parsed_info->options, ",",
				sizeof(parsed_info->options));
		strlcat(parsed_info->options, "domain=",
			sizeof(parsed_info->options));
		strlcat(parsed_info->options, parsed_info->domain,
			sizeof(parsed_info->options));
	} else if (parsed_info->got_domain) {
		strlcat(parsed_info->options, ",domain=",
			sizeof(parsed_info->options));
	}

assemble_exit:
	return rc;
}

/*
 * chdir() into the mountpoint and determine "realpath". We assume here that
 * "mountpoint" is a statically allocated string and does not need to be freed.
 */
static int
acquire_mountpoint(char **mountpointp)
{
	int rc, dacrc;
	uid_t realuid, oldfsuid;
	gid_t oldfsgid;
	char *mountpoint;

	/*
	 * Acquire the necessary privileges to chdir to the mountpoint. If
	 * the real uid is root, then we reacquire CAP_DAC_READ_SEARCH. If
	 * it's not, then we change the fsuid to the real uid to ensure that
	 * the mounting user actually has access to the mountpoint.
	 *
	 * The mount(8) manpage does not state that users must be able to
	 * chdir into the mountpoint in order to mount onto it, but if we
	 * allow that, then an unprivileged user could use this program to
	 * "probe" into directories to which he does not have access.
	 */
	realuid = getuid();
	if (realuid == 0) {
		dacrc = toggle_dac_capability(0, 1);
		if (dacrc)
			return dacrc;
	} else {
		oldfsuid = setfsuid(realuid);
		oldfsgid = setfsgid(getgid());
	}

	rc = chdir(*mountpointp);
	if (rc) {
		fprintf(stderr, "Couldn't chdir to %s: %s\n", *mountpointp,
			strerror(errno));
		rc = EX_USAGE;
		goto restore_privs;
	}

	mountpoint = realpath(".", NULL);
	if (!mountpoint) {
		fprintf(stderr, "Unable to resolve %s to canonical path: %s\n",
			*mountpointp, strerror(errno));
		rc = EX_SYSERR;
	}

	*mountpointp = mountpoint;
restore_privs:
	if (realuid == 0) {
		dacrc = toggle_dac_capability(0, 0);
		if (dacrc)
			rc = rc ? rc : dacrc;
	} else {
		uid_t __attribute__((unused)) uignore = setfsuid(oldfsuid);
		gid_t __attribute__((unused)) gignore = setfsgid(oldfsgid);
	}

	return rc;
}

int main(int argc, char **argv)
{
	int c;
	char *orgoptions = NULL;
	char *mountpoint = NULL;
	char *options = NULL;
	char *orig_dev = NULL;
	char *currentaddress, *nextaddress;
	int rc = 0;
	int already_uppercased = 0;
	int sloppy = 0;
	size_t options_size = MAX_OPTIONS_LEN;
	struct parsed_mount_info *parsed_info = NULL;
	pid_t pid;

	rc = check_setuid();
	if (rc)
		return rc;

	rc = drop_capabilities(1);
	if (rc)
		return EX_SYSERR;

	/* setlocale(LC_ALL, "");
	   bindtextdomain(PACKAGE, LOCALEDIR);
	   textdomain(PACKAGE); */

	if (!argc || !argv) {
		rc = mount_usage(stderr);
		goto mount_exit;
	}

	thisprogram = basename(argv[0]);
	if (thisprogram == NULL)
		thisprogram = "mount.cifs";

	/* allocate parsed_info as shared anonymous memory range */
	parsed_info = mmap((void *)0, sizeof(*parsed_info), PROT_READ | PROT_WRITE,
			   MAP_ANONYMOUS | MAP_SHARED, -1, 0);
	if (parsed_info == (struct parsed_mount_info *) -1) {
		parsed_info = NULL;
		fprintf(stderr, "Unable to allocate memory: %s\n",
				strerror(errno));
		return EX_SYSERR;
	}

	/* add sharename in opts string as unc= parm */
	while ((c = getopt_long(argc, argv, "?fhno:rsvVw",
				longopts, NULL)) != -1) {
		switch (c) {
		case '?':
		case 'h':	/* help */
			rc = mount_usage(stdout);
			goto mount_exit;
		case 'n':
			++parsed_info->nomtab;
			break;
		case 'o':
			orgoptions = strndup(optarg, MAX_OPTIONS_LEN);
			if (!orgoptions) {
				rc = EX_SYSERR;
				goto mount_exit;
			}
			break;
		case 'r':	/* mount readonly */
			parsed_info->flags |= MS_RDONLY;
			break;
		case 'v':
			++parsed_info->verboseflag;
			break;
		case 'V':
			print_cifs_mount_version();
			exit(0);
		case 'w':
			parsed_info->flags &= ~MS_RDONLY;
			break;
		case 'f':
			++parsed_info->fakemnt;
			break;
		case 's':
			++sloppy;
			break;
		default:
			fprintf(stderr, "unknown command-line option: %c\n", c);
			rc = mount_usage(stderr);
			goto mount_exit;
		}
	}

	if (argc < optind + 2) {
		rc = mount_usage(stderr);
		goto mount_exit;
	}

	orig_dev = argv[optind];
	mountpoint = argv[optind + 1];

	/* chdir into mountpoint as soon as possible */
	rc = acquire_mountpoint(&mountpoint);
	if (rc)
		return rc;

	/*
	 * mount.cifs does privilege separation. Most of the code to handle
	 * assembling the mount info is done in a child process that drops
	 * privileges. The info is assembled in parsed_info which is a
	 * shared, mmaped memory segment. The parent waits for the child to
	 * exit and checks the return code. If it's anything but "0", then
	 * the process exits without attempting anything further.
	 */
	pid = fork();
	if (pid == -1) {
		fprintf(stderr, "Unable to fork: %s\n", strerror(errno));
		rc = EX_SYSERR;
		goto mount_exit;
	} else if (!pid) {
		/* child */
		rc = assemble_mountinfo(parsed_info, thisprogram, mountpoint,
					orig_dev, orgoptions);
		return rc;
	} else {
		/* parent */
		pid = wait(&rc);
		if (!WIFEXITED(rc)) {
			fprintf(stderr, "Child process terminated abnormally.\n");
			rc = EX_SYSERR;
			goto mount_exit;
		}
		rc = WEXITSTATUS(rc);
		if (rc)
			goto mount_exit;
	}

	options = calloc(options_size, 1);
	if (!options) {
		fprintf(stderr, "Unable to allocate memory.\n");
		rc = EX_SYSERR;
		goto mount_exit;
	}

	currentaddress = parsed_info->addrlist;
	nextaddress = strchr(currentaddress, ',');
	if (nextaddress)
		*nextaddress++ = '\0';

mount_retry:
	if (!currentaddress) {
		fprintf(stderr, "Unable to find suitable address.\n");
		rc = parsed_info->nofail ? 0 : EX_FAIL;
		goto mount_exit;
	}
	strlcpy(options, "ip=", options_size);
	strlcat(options, currentaddress, options_size);

	strlcat(options, ",unc=\\\\", options_size);
	strlcat(options, parsed_info->host, options_size);
	strlcat(options, "\\", options_size);
	strlcat(options, parsed_info->share, options_size);

	if (*parsed_info->options) {
		strlcat(options, ",", options_size);
		strlcat(options, parsed_info->options, options_size);
	}

	if (*parsed_info->prefix) {
		strlcat(options, ",prefixpath=", options_size);
		strlcat(options, parsed_info->prefix, options_size);
	}

	if (sloppy)
		strlcat(options, ",sloppy", options_size);

	if (parsed_info->verboseflag)
		fprintf(stderr, "%s kernel mount options: %s",
			thisprogram, options);

	if (parsed_info->got_password) {
		/*
		 * Commas have to be doubled, or else they will
		 * look like the parameter separator
		 */
		strlcat(options, ",pass=", options_size);
		strlcat(options, parsed_info->password, options_size);
		if (parsed_info->verboseflag)
			fprintf(stderr, ",pass=********");
	}

	if (parsed_info->verboseflag)
		fprintf(stderr, "\n");

	rc = check_mtab(thisprogram, orig_dev, mountpoint);
	if (rc)
		goto mount_exit;

	if (!parsed_info->fakemnt) {
		toggle_dac_capability(0, 1);
		rc = mount(orig_dev, ".", cifs_fstype, parsed_info->flags, options);
		toggle_dac_capability(0, 0);
		if (rc == 0)
			goto do_mtab;

		switch (errno) {
		case ECONNREFUSED:
		case EHOSTUNREACH:
			currentaddress = nextaddress;
			if (currentaddress) {
				nextaddress = strchr(currentaddress, ',');
				if (nextaddress)
					*nextaddress++ = '\0';
			}
			goto mount_retry;
		case ENODEV:
			fprintf(stderr,
				"mount error: %s filesystem not supported by the system\n", cifs_fstype);
			break;
		case ENXIO:
			if (!already_uppercased &&
			    uppercase_string(parsed_info->host) &&
			    uppercase_string(parsed_info->share) &&
			    uppercase_string(parsed_info->prefix) &&
			    uppercase_string(orig_dev)) {
				fprintf(stderr,
					"Retrying with upper case share name\n");
				already_uppercased = 1;
				goto mount_retry;
			}
		}
		fprintf(stderr, "mount error(%d): %s\n", errno,
			strerror(errno));
		fprintf(stderr,
			"Refer to the %s(8) manual page (e.g. man "
			"%s)\n", thisprogram, thisprogram);
		rc = EX_FAIL;
		goto mount_exit;
	}

do_mtab:
	if (!parsed_info->nomtab && !mtab_unusable()) {
		if (parsed_info->flags & MS_REMOUNT) {
			rc = del_mtab(mountpoint);
			if (rc)
				goto mount_exit;
		}

		rc = add_mtab(orig_dev, mountpoint, parsed_info->flags, cifs_fstype);
	}

mount_exit:
	if (parsed_info) {
		memset(parsed_info->password, 0, sizeof(parsed_info->password));
		munmap(parsed_info, sizeof(*parsed_info));
	}
	free(options);
	free(orgoptions);
	return rc;
}