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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
ddeb4241 LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2013 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 | ||
11c3a366 | 21 | #include <errno.h> |
ddeb4241 | 22 | #include <fcntl.h> |
11c3a366 TA |
23 | #include <sys/stat.h> |
24 | #include <unistd.h> | |
349cc4a5 | 25 | #if HAVE_LINUX_MEMFD_H |
07630cea | 26 | #include <linux/memfd.h> |
27c64db6 | 27 | #endif |
07630cea LP |
28 | #include <stdio.h> |
29 | #include <sys/mman.h> | |
30 | #include <sys/prctl.h> | |
27c64db6 | 31 | |
b5efdb8a | 32 | #include "alloc-util.h" |
3ffd4af2 | 33 | #include "fd-util.h" |
93cc7779 | 34 | #include "macro.h" |
3ffd4af2 | 35 | #include "memfd-util.h" |
07630cea LP |
36 | #include "missing.h" |
37 | #include "string-util.h" | |
38 | #include "utf8.h" | |
ddeb4241 | 39 | |
4531a9bc | 40 | int memfd_new(const char *name) { |
7f96b1d8 | 41 | _cleanup_free_ char *g = NULL; |
4531a9bc | 42 | int fd; |
ddeb4241 | 43 | |
5755381f | 44 | if (!name) { |
7f96b1d8 LP |
45 | char pr[17] = {}; |
46 | ||
47 | /* If no name is specified we generate one. We include | |
48 | * a hint indicating our library implementation, and | |
49 | * add the thread name to it */ | |
50 | ||
51 | assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0); | |
52 | ||
53 | if (isempty(pr)) | |
54 | name = "sd"; | |
55 | else { | |
5755381f LP |
56 | _cleanup_free_ char *e = NULL; |
57 | ||
58 | e = utf8_escape_invalid(pr); | |
59 | if (!e) | |
60 | return -ENOMEM; | |
61 | ||
62 | g = strappend("sd-", e); | |
7f96b1d8 LP |
63 | if (!g) |
64 | return -ENOMEM; | |
65 | ||
66 | name = g; | |
67 | } | |
68 | } | |
69 | ||
45071fca | 70 | fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); |
4531a9bc | 71 | if (fd < 0) |
a6082d77 | 72 | return -errno; |
ddeb4241 | 73 | |
4531a9bc | 74 | return fd; |
ddeb4241 LP |
75 | } |
76 | ||
fac9c0d5 | 77 | int memfd_map(int fd, uint64_t offset, size_t size, void **p) { |
ddeb4241 LP |
78 | void *q; |
79 | int sealed; | |
80 | ||
4531a9bc LP |
81 | assert(fd >= 0); |
82 | assert(size > 0); | |
83 | assert(p); | |
ddeb4241 | 84 | |
fac9c0d5 | 85 | sealed = memfd_get_sealed(fd); |
ddeb4241 LP |
86 | if (sealed < 0) |
87 | return sealed; | |
88 | ||
23972f42 | 89 | if (sealed) |
fac9c0d5 | 90 | q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset); |
23972f42 | 91 | else |
fac9c0d5 | 92 | q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset); |
23972f42 | 93 | |
ddeb4241 LP |
94 | if (q == MAP_FAILED) |
95 | return -errno; | |
96 | ||
97 | *p = q; | |
98 | return 0; | |
99 | } | |
100 | ||
fac9c0d5 | 101 | int memfd_set_sealed(int fd) { |
ddeb4241 LP |
102 | int r; |
103 | ||
4531a9bc | 104 | assert(fd >= 0); |
ddeb4241 | 105 | |
db74cc0d | 106 | r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
107 | if (r < 0) |
108 | return -errno; | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
fac9c0d5 | 113 | int memfd_get_sealed(int fd) { |
a6082d77 | 114 | int r; |
ddeb4241 | 115 | |
4531a9bc | 116 | assert(fd >= 0); |
ddeb4241 | 117 | |
fac9c0d5 | 118 | r = fcntl(fd, F_GET_SEALS); |
ddeb4241 LP |
119 | if (r < 0) |
120 | return -errno; | |
121 | ||
db74cc0d | 122 | return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
123 | } |
124 | ||
fac9c0d5 | 125 | int memfd_get_size(int fd, uint64_t *sz) { |
a6082d77 | 126 | struct stat stat; |
4531a9bc | 127 | int r; |
ddeb4241 | 128 | |
4531a9bc LP |
129 | assert(fd >= 0); |
130 | assert(sz); | |
ddeb4241 | 131 | |
fac9c0d5 | 132 | r = fstat(fd, &stat); |
ddeb4241 LP |
133 | if (r < 0) |
134 | return -errno; | |
135 | ||
a6082d77 | 136 | *sz = stat.st_size; |
5755381f | 137 | return 0; |
ddeb4241 LP |
138 | } |
139 | ||
fac9c0d5 | 140 | int memfd_set_size(int fd, uint64_t sz) { |
ddeb4241 LP |
141 | int r; |
142 | ||
4531a9bc | 143 | assert(fd >= 0); |
ddeb4241 | 144 | |
fac9c0d5 | 145 | r = ftruncate(fd, sz); |
ddeb4241 LP |
146 | if (r < 0) |
147 | return -errno; | |
148 | ||
5755381f | 149 | return 0; |
ddeb4241 | 150 | } |
453a0c29 | 151 | |
4531a9bc LP |
152 | int memfd_new_and_map(const char *name, size_t sz, void **p) { |
153 | _cleanup_close_ int fd = -1; | |
453a0c29 LP |
154 | int r; |
155 | ||
4531a9bc LP |
156 | assert(sz > 0); |
157 | assert(p); | |
158 | ||
159 | fd = memfd_new(name); | |
160 | if (fd < 0) | |
161 | return fd; | |
453a0c29 | 162 | |
4531a9bc | 163 | r = memfd_set_size(fd, sz); |
8a02deca | 164 | if (r < 0) |
453a0c29 | 165 | return r; |
453a0c29 | 166 | |
4531a9bc | 167 | r = memfd_map(fd, 0, sz, p); |
8a02deca | 168 | if (r < 0) |
453a0c29 | 169 | return r; |
453a0c29 | 170 | |
4531a9bc LP |
171 | r = fd; |
172 | fd = -1; | |
173 | ||
174 | return r; | |
453a0c29 | 175 | } |