1/*
2 *  smbmnt.c
3 *
4 *  Copyright (C) 1995-1998 by Paal-Kr. Engstad and Volker Lendecke
5 *  extensively modified by Tridge
6 *
7 */
8
9#include "includes.h"
10
11#include <mntent.h>
12#include <sys/utsname.h>
13
14#include <asm/types.h>
15#include <asm/posix_types.h>
16#include <linux/smb.h>
17#include <linux/smb_mount.h>
18#include <asm/unistd.h>
19
20#ifndef	MS_MGC_VAL
21/* This may look strange but MS_MGC_VAL is what we are looking for and
22	is what we need from <linux/fs.h> under libc systems and is
23	provided in standard includes on glibc systems.  So...  We
24	switch on what we need...  */
25#include <linux/fs.h>
26#endif
27
28static uid_t mount_uid;
29static gid_t mount_gid;
30static int mount_ro;
31static unsigned mount_fmask;
32static unsigned mount_dmask;
33static int user_mount;
34static char *options;
35
36static void
37help(void)
38{
39        printf("\n");
40        printf("Usage: smbmnt mount-point [options]\n");
41	printf("Version %s\n\n",SAMBA_VERSION_STRING);
42        printf("-s share       share name on server\n"
43               "-r             mount read-only\n"
44               "-u uid         mount as uid\n"
45               "-g gid         mount as gid\n"
46               "-f mask        permission mask for files\n"
47               "-d mask        permission mask for directories\n"
48               "-o options     name=value, list of options\n"
49               "-h             print this help text\n");
50}
51
52static int
53parse_args(int argc, char *argv[], struct smb_mount_data *data, char **share)
54{
55        int opt;
56
57        while ((opt = getopt (argc, argv, "s:u:g:rf:d:o:")) != EOF)
58	{
59                switch (opt)
60		{
61                case 's':
62                        *share = optarg;
63                        break;
64                case 'u':
65			if (!user_mount) {
66				mount_uid = strtol(optarg, NULL, 0);
67			}
68                        break;
69                case 'g':
70			if (!user_mount) {
71				mount_gid = strtol(optarg, NULL, 0);
72			}
73                        break;
74                case 'r':
75                        mount_ro = 1;
76                        break;
77                case 'f':
78                        mount_fmask = strtol(optarg, NULL, 8);
79                        break;
80                case 'd':
81                        mount_dmask = strtol(optarg, NULL, 8);
82                        break;
83		case 'o':
84			options = optarg;
85			break;
86                default:
87                        return -1;
88                }
89        }
90        return 0;
91
92}
93
94static char *
95fullpath(const char *p)
96{
97        char path[PATH_MAX+1];
98
99	if (strlen(p) > PATH_MAX) {
100		return NULL;
101	}
102
103        if (realpath(p, path) == NULL) {
104		fprintf(stderr,"Failed to find real path for mount point\n");
105		exit(1);
106	}
107	return strdup(path);
108}
109
110/* Check whether user is allowed to mount on the specified mount point. If it's
111   OK then we change into that directory - this prevents race conditions */
112static int mount_ok(char *mount_point)
113{
114	struct stat st;
115
116	if (chdir(mount_point) != 0) {
117		return -1;
118	}
119
120        if (stat(".", &st) != 0) {
121		return -1;
122        }
123
124        if (!S_ISDIR(st.st_mode)) {
125                errno = ENOTDIR;
126                return -1;
127        }
128
129        if ((getuid() != 0) &&
130	    ((getuid() != st.st_uid) ||
131	     ((st.st_mode & S_IRWXU) != S_IRWXU))) {
132                errno = EPERM;
133                return -1;
134        }
135
136        return 0;
137}
138
139/* Tries to mount using the appropriate format. For 2.2 the struct,
140   for 2.4 the ascii version. */
141static int
142do_mount(char *share_name, unsigned int flags, struct smb_mount_data *data)
143{
144	pstring opts;
145	struct utsname uts;
146	char *release, *major, *minor;
147	char *data1, *data2;
148
149	uname(&uts);
150	release = uts.release;
151	major = strtok(release, ".");
152	minor = strtok(NULL, ".");
153	if (major && minor && atoi(major) == 2 && atoi(minor) < 4) {
154		/* < 2.4, assume struct */
155		data1 = (char *) data;
156		data2 = opts;
157	} else {
158		/* >= 2.4, assume ascii but fall back on struct */
159		data1 = opts;
160		data2 = (char *) data;
161	}
162
163	slprintf(opts, sizeof(opts)-1,
164		 "version=7,uid=%d,gid=%d,file_mode=0%o,dir_mode=0%o,%s",
165		 data->uid, data->gid, data->file_mode, data->dir_mode,options);
166	if (mount(share_name, ".", "smbfs", flags, data1) == 0)
167		return 0;
168	return mount(share_name, ".", "smbfs", flags, data2);
169}
170
171 int main(int argc, char *argv[])
172{
173	char *mount_point, *share_name = NULL;
174	FILE *mtab;
175	int fd;
176	unsigned int flags;
177	struct smb_mount_data data;
178	struct mntent ment;
179
180	memset(&data, 0, sizeof(struct smb_mount_data));
181
182	if (argc < 2) {
183		help();
184		exit(1);
185	}
186
187	if (argv[1][0] == '-') {
188		help();
189		exit(1);
190	}
191
192	if (getuid() != 0) {
193		user_mount = 1;
194	}
195
196        if (geteuid() != 0) {
197                fprintf(stderr, "smbmnt must be installed suid root for direct user mounts (%d,%d)\n", getuid(), geteuid());
198                exit(1);
199        }
200
201	mount_uid = getuid();
202	mount_gid = getgid();
203	mount_fmask = umask(0);
204        umask(mount_fmask);
205	mount_fmask = ~mount_fmask;
206
207        mount_point = fullpath(argv[1]);
208
209        argv += 1;
210        argc -= 1;
211
212        if (mount_ok(mount_point) != 0) {
213                fprintf(stderr, "cannot mount on %s: %s\n",
214                        mount_point, strerror(errno));
215                exit(1);
216        }
217
218	data.version = SMB_MOUNT_VERSION;
219
220        /* getuid() gives us the real uid, who may umount the fs */
221        data.mounted_uid = getuid();
222
223        if (parse_args(argc, argv, &data, &share_name) != 0) {
224                help();
225                return -1;
226        }
227
228        data.uid = mount_uid;
229        data.gid = mount_gid;
230        data.file_mode = (S_IRWXU|S_IRWXG|S_IRWXO) & mount_fmask;
231        data.dir_mode  = (S_IRWXU|S_IRWXG|S_IRWXO) & mount_dmask;
232
233        if (mount_dmask == 0) {
234                data.dir_mode = data.file_mode;
235                if ((data.dir_mode & S_IRUSR) != 0)
236                        data.dir_mode |= S_IXUSR;
237                if ((data.dir_mode & S_IRGRP) != 0)
238                        data.dir_mode |= S_IXGRP;
239                if ((data.dir_mode & S_IROTH) != 0)
240                        data.dir_mode |= S_IXOTH;
241        }
242
243	flags = MS_MGC_VAL;
244
245	if (mount_ro) flags |= MS_RDONLY;
246
247	if (do_mount(share_name, flags, &data) < 0) {
248		switch (errno) {
249		case ENODEV:
250			fprintf(stderr, "ERROR: smbfs filesystem not supported by the kernel\n");
251			break;
252		default:
253			perror("mount error");
254		}
255		fprintf(stderr, "Please refer to the smbmnt(8) manual page\n");
256		return -1;
257	}
258
259        ment.mnt_fsname = share_name ? share_name : "none";
260        ment.mnt_dir = mount_point;
261        ment.mnt_type = "smbfs";
262        ment.mnt_opts = "";
263        ment.mnt_freq = 0;
264        ment.mnt_passno= 0;
265
266        mount_point = ment.mnt_dir;
267
268	if (mount_point == NULL)
269	{
270		fprintf(stderr, "Mount point too long\n");
271		return -1;
272	}
273
274        if ((fd = open(MOUNTED"~", O_RDWR|O_CREAT|O_EXCL, 0600)) == -1)
275        {
276                fprintf(stderr, "Can't get "MOUNTED"~ lock file");
277                return 1;
278        }
279        close(fd);
280
281        if ((mtab = setmntent(MOUNTED, "a+")) == NULL)
282        {
283                fprintf(stderr, "Can't open " MOUNTED);
284                return 1;
285        }
286
287        if (addmntent(mtab, &ment) == 1)
288        {
289                fprintf(stderr, "Can't write mount entry");
290                return 1;
291        }
292        if (fchmod(fileno(mtab), 0644) == -1)
293        {
294                fprintf(stderr, "Can't set perms on "MOUNTED);
295                return 1;
296        }
297        endmntent(mtab);
298
299        if (unlink(MOUNTED"~") == -1)
300        {
301                fprintf(stderr, "Can't remove "MOUNTED"~");
302                return 1;
303        }
304
305	return 0;
306}
307