]>
Commit | Line | Data |
---|---|---|
53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
8c1be37e LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2016 Lennart Poettering | |
6 | ||
7 | systemd is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU Lesser General Public License as published by | |
9 | the Free Software Foundation; either version 2.1 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | systemd is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | Lesser General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public License | |
18 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
19 | ***/ | |
20 | ||
dccca82b | 21 | #include <errno.h> |
8c1be37e LP |
22 | #include <fcntl.h> |
23 | #include <linux/loop.h> | |
24 | #include <sys/ioctl.h> | |
25 | #include <sys/stat.h> | |
26 | ||
27 | #include "alloc-util.h" | |
28 | #include "fd-util.h" | |
29 | #include "loop-util.h" | |
3cc44114 | 30 | #include "stat-util.h" |
8c1be37e LP |
31 | |
32 | int loop_device_make(int fd, int open_flags, LoopDevice **ret) { | |
33 | const struct loop_info64 info = { | |
34 | .lo_flags = LO_FLAGS_AUTOCLEAR|LO_FLAGS_PARTSCAN|(open_flags == O_RDONLY ? LO_FLAGS_READ_ONLY : 0), | |
35 | }; | |
36 | ||
37 | _cleanup_close_ int control = -1, loop = -1; | |
38 | _cleanup_free_ char *loopdev = NULL; | |
39 | struct stat st; | |
40 | LoopDevice *d; | |
3cc44114 | 41 | int nr, r; |
8c1be37e LP |
42 | |
43 | assert(fd >= 0); | |
44 | assert(ret); | |
45 | assert(IN_SET(open_flags, O_RDWR, O_RDONLY)); | |
46 | ||
47 | if (fstat(fd, &st) < 0) | |
48 | return -errno; | |
49 | ||
50 | if (S_ISBLK(st.st_mode)) { | |
51 | int copy; | |
52 | ||
53 | /* If this is already a block device, store a copy of the fd as it is */ | |
54 | ||
55 | copy = fcntl(fd, F_DUPFD_CLOEXEC, 3); | |
56 | if (copy < 0) | |
57 | return -errno; | |
58 | ||
59 | d = new0(LoopDevice, 1); | |
60 | if (!d) | |
61 | return -ENOMEM; | |
62 | ||
63 | *d = (LoopDevice) { | |
64 | .fd = copy, | |
65 | .nr = -1, | |
66 | }; | |
67 | ||
68 | *ret = d; | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
3cc44114 LP |
73 | r = stat_verify_regular(&st); |
74 | if (r < 0) | |
75 | return r; | |
8c1be37e LP |
76 | |
77 | control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); | |
78 | if (control < 0) | |
79 | return -errno; | |
80 | ||
81 | nr = ioctl(control, LOOP_CTL_GET_FREE); | |
82 | if (nr < 0) | |
83 | return -errno; | |
84 | ||
85 | if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) | |
86 | return -ENOMEM; | |
87 | ||
88 | loop = open(loopdev, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags); | |
89 | if (loop < 0) | |
90 | return -errno; | |
91 | ||
92 | if (ioctl(loop, LOOP_SET_FD, fd) < 0) | |
93 | return -errno; | |
94 | ||
95 | if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) | |
96 | return -errno; | |
97 | ||
98 | d = new(LoopDevice, 1); | |
99 | if (!d) | |
100 | return -ENOMEM; | |
101 | ||
102 | *d = (LoopDevice) { | |
103 | .fd = loop, | |
104 | .node = loopdev, | |
105 | .nr = nr, | |
106 | }; | |
107 | ||
108 | loop = -1; | |
109 | loopdev = NULL; | |
110 | ||
111 | *ret = d; | |
112 | ||
113 | return (*ret)->fd; | |
114 | } | |
115 | ||
116 | int loop_device_make_by_path(const char *path, int open_flags, LoopDevice **ret) { | |
117 | _cleanup_close_ int fd = -1; | |
118 | ||
119 | assert(path); | |
120 | assert(ret); | |
121 | assert(IN_SET(open_flags, O_RDWR, O_RDONLY)); | |
122 | ||
123 | fd = open(path, O_CLOEXEC|O_NONBLOCK|O_NOCTTY|open_flags); | |
124 | if (fd < 0) | |
125 | return -errno; | |
126 | ||
127 | return loop_device_make(fd, open_flags, ret); | |
128 | } | |
129 | ||
130 | LoopDevice* loop_device_unref(LoopDevice *d) { | |
131 | if (!d) | |
132 | return NULL; | |
133 | ||
134 | if (d->fd >= 0) { | |
135 | ||
a2ea3b2f | 136 | if (d->nr >= 0 && !d->relinquished) { |
8c1be37e LP |
137 | if (ioctl(d->fd, LOOP_CLR_FD) < 0) |
138 | log_debug_errno(errno, "Failed to clear loop device: %m"); | |
139 | ||
140 | } | |
141 | ||
142 | safe_close(d->fd); | |
143 | } | |
144 | ||
a2ea3b2f | 145 | if (d->nr >= 0 && !d->relinquished) { |
8c1be37e LP |
146 | _cleanup_close_ int control = -1; |
147 | ||
148 | control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); | |
149 | if (control < 0) | |
150 | log_debug_errno(errno, "Failed to open loop control device: %m"); | |
151 | else { | |
152 | if (ioctl(control, LOOP_CTL_REMOVE, d->nr) < 0) | |
153 | log_debug_errno(errno, "Failed to remove loop device: %m"); | |
154 | } | |
155 | } | |
156 | ||
157 | free(d->node); | |
5fecf46d | 158 | return mfree(d); |
8c1be37e | 159 | } |
a2ea3b2f LP |
160 | |
161 | void loop_device_relinquish(LoopDevice *d) { | |
162 | assert(d); | |
163 | ||
164 | /* Don't attempt to clean up the loop device anymore from this point on. Leave the clean-ing up to the kernel | |
165 | * itself, using the loop device "auto-clear" logic we already turned on when creating the device. */ | |
166 | ||
167 | d->relinquished = true; | |
168 | } |