summaryrefslogtreecommitdiffstats
path: root/contrib/fuse-lib/mount.c
blob: 922d9e464db17cdee7d4a20ca8f65f0cd4e63b86 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
  Copyright (c) 2010 Gluster, Inc. <http://www.gluster.com>

  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB.
*/

#include "mount_util.h"
#include "mount-gluster-compat.h"

#ifdef GF_FUSERMOUNT
#define FUSERMOUNT_PROG FUSERMOUNT_DIR "/fusermount-glusterfs"
#else
#define FUSERMOUNT_PROG "fusermount"
#endif
#define FUSE_DEVFD_ENV "_FUSE_DEVFD"


/* FUSE: function is called fuse_kern_unmount() */
void
gf_fuse_unmount (const char *mountpoint, int fd)
{
        int res;
        int pid;

        if (!mountpoint)
                return;

        if (fd != -1) {
                struct pollfd pfd;

                pfd.fd = fd;
                pfd.events = 0;
                res = poll (&pfd, 1, 0);
                /* If file poll returns POLLERR on the device file descriptor,
                   then the filesystem is already unmounted */
                if (res == 1 && (pfd.revents & POLLERR))
                        return;

                /* Need to close file descriptor, otherwise synchronous umount
                   would recurse into filesystem, and deadlock */
                close (fd);
        }

        if (geteuid () == 0) {
                fuse_mnt_umount ("fuse", mountpoint, mountpoint, 1);
                return;
        }

        res = umount2 (mountpoint, 2);
        if (res == 0)
                return;

        pid = fork ();
        if (pid == -1)
                return;

        if (pid == 0) {
                const char *argv[] = { FUSERMOUNT_PROG, "-u", "-q", "-z",
                                       "--", mountpoint, NULL };

                execvp (FUSERMOUNT_PROG, (char **)argv);
                _exit (1);
        }
        waitpid (pid, NULL, 0);
}


/* gluster-specific routines */

static char *
escape (char *s)
{
        size_t len = 0;
        char *p = NULL;
        char *q = NULL;
        char *e = NULL;

        for (p = s; *p; p++) {
                if (*p == ',')
                       len++;
                len++;
        }

        e = CALLOC (1, len + 1);
        if (!e)
                return NULL;

        for (p = s, q = e; *p; p++, q++) {
                if (*p == ',') {
                        *q = '\\';
                        q++;
                }
                *q = *p;
        }

        return e;
}

static int
fuse_mount_fusermount (const char *mountpoint, char *fsname,
                       unsigned long mountflags, char *mnt_param,
                       int fd)
{
        int  pid = -1;
        int  res = 0;
        int  ret = -1;
        char *fm_mnt_params = NULL;
        char *efsname = NULL;

#ifndef GF_FUSERMOUNT
        GFFUSE_LOGERR ("Mounting via helper utility "
                       "(unprivileged mounting) is supported "
                       "only if glusterfs is compiled with "
                       "--enable-fusermount");
        return -1;
#endif

        efsname = escape (fsname);
        if (!efsname) {
                GFFUSE_LOGERR ("Out of memory");

                return -1;
        }
        ret = asprintf (&fm_mnt_params,
                        "%s%s,fsname=%s,nonempty,subtype=glusterfs",
                        (mountflags & MS_RDONLY) ? "ro," : "",
                        mnt_param, efsname);
        FREE (efsname);
        if (ret == -1) {
                GFFUSE_LOGERR ("Out of memory");

                goto out;
        }

        /* fork to exec fusermount */
        pid = fork ();
        if (pid == -1) {
                GFFUSE_LOGERR ("fork() failed: %s", strerror (errno));
                ret = -1;
                goto out;
        }

        if (pid == 0) {
                char env[10];
                const char *argv[32];
                int a = 0;

                argv[a++] = FUSERMOUNT_PROG;
                argv[a++] = "-o";
                argv[a++] = fm_mnt_params;
                argv[a++] = "--";
                argv[a++] = mountpoint;
                argv[a++] = NULL;

                snprintf (env, sizeof (env), "%i", fd);
                setenv (FUSE_DEVFD_ENV, env, 1);
                execvp (FUSERMOUNT_PROG, (char **)argv);
                GFFUSE_LOGERR ("failed to exec fusermount: %s",
                               strerror (errno));
                _exit (1);
        }

        ret = waitpid (pid, &res, 0);
        ret = (ret == pid && res == 0) ? 0 : -1;
 out:
        FREE (fm_mnt_params);
        return ret;
}

static int
fuse_mount_sys (const char *mountpoint, char *fsname,
                unsigned long mountflags, char *mnt_param, int fd)
{
        int ret = -1;
        unsigned mounted = 0;
        char *mnt_param_mnt = NULL;
        char *fstype = "fuse.glusterfs";
        char *source = fsname;

        ret = asprintf (&mnt_param_mnt,
                        "%s,fd=%i,rootmode=%o,user_id=%i,group_id=%i",
                        mnt_param, fd, S_IFDIR, getuid (), getgid ());
        if (ret == -1) {
                GFFUSE_LOGERR ("Out of memory");

                goto out;
        }
        ret = mount (source, mountpoint, fstype, mountflags,
                     mnt_param_mnt);
        if (ret == -1 && errno == ENODEV) {
                /* fs subtype support was added by 79c0b2df aka
                   v2.6.21-3159-g79c0b2d. Probably we have an
                   older kernel ... */
                fstype = "fuse";
                ret = asprintf (&source, "glusterfs#%s", fsname);
                if (ret == -1) {
                        GFFUSE_LOGERR ("Out of memory");

                        goto out;
                }
                ret = mount (source, mountpoint, fstype, mountflags,
                             mnt_param_mnt);
        }
        if (ret == -1)
                goto out;
        else
                mounted = 1;

#ifndef __NetBSD__
        if (geteuid () == 0) {
                char *newmnt = fuse_mnt_resolve_path ("fuse", mountpoint);
                char *mnt_param_mtab = NULL;

                if (!newmnt) {
                        ret = -1;

                        goto out;
                }

                ret = asprintf (&mnt_param_mtab, "%s%s",
                                mountflags & MS_RDONLY ? "ro," : "",
                                mnt_param);
                if (ret == -1)
                        GFFUSE_LOGERR ("Out of memory");
                else {
                        ret = fuse_mnt_add_mount ("fuse", source, newmnt,
                                                  fstype, mnt_param_mtab);
                        FREE (mnt_param_mtab);
                }

                FREE (newmnt);
                if (ret == -1) {
                        GFFUSE_LOGERR ("failed to add mtab entry");

                        goto out;
                }
        }
#endif /* __NetBSD__ */

out:
        if (ret == -1) {
                if (mounted)
                        umount2 (mountpoint, 2); /* lazy umount */
        }
        FREE (mnt_param_mnt);
        if (source != fsname)
                FREE (source);

        return ret;
}

int
gf_fuse_mount (const char *mountpoint, char *fsname,
               unsigned long mountflags, char *mnt_param,
               pid_t *mnt_pid, int status_fd)
{
        int   fd  = -1;
        pid_t pid = -1;
        int   ret = -1;

        fd = open ("/dev/fuse", O_RDWR);
        if (fd == -1) {
                GFFUSE_LOGERR ("cannot open /dev/fuse (%s)",
                                strerror (errno));
                return -1;
        }

        /* start mount agent */
        pid = fork();
        switch (pid) {
        case 0:
                /* hello it's mount agent */
                if (!mnt_pid) {
                        /* daemonize mount agent, caller is
                         * not interested in waiting for it
                         */
                        pid = fork ();
                        if (pid)
                                exit (pid == -1 ? 1 : 0);
                }

                ret = fuse_mount_sys (mountpoint, fsname, mountflags, mnt_param, fd);
                if (ret == -1) {
                        gf_log ("glusterfs-fuse", GF_LOG_INFO,
                                "direct mount failed (%s), "
                                "retry to mount via fusermount",
                                strerror (errno));

                        ret = fuse_mount_fusermount (mountpoint, fsname, mountflags,
                                                     mnt_param, fd);
                }

                if (ret == -1)
                        GFFUSE_LOGERR ("mount of %s to %s (%s) failed",
                                       fsname, mountpoint, mnt_param);

                if (status_fd >= 0)
                        (void)write (status_fd, &ret, sizeof (ret));
                exit (!!ret);
                /* bye mount agent */
        case -1:
                close (fd);
                fd = -1;
        }

        if (mnt_pid)
               *mnt_pid = pid;

        return fd;
}