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Commit | Line | Data |
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ddeb4241 LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2013 Lennart Poettering | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
11c3a366 | 20 | #include <errno.h> |
ddeb4241 | 21 | #include <fcntl.h> |
11c3a366 TA |
22 | #include <sys/stat.h> |
23 | #include <unistd.h> | |
27c64db6 | 24 | #ifdef HAVE_LINUX_MEMFD_H |
07630cea | 25 | #include <linux/memfd.h> |
27c64db6 | 26 | #endif |
07630cea LP |
27 | #include <stdio.h> |
28 | #include <sys/mman.h> | |
29 | #include <sys/prctl.h> | |
27c64db6 | 30 | |
b5efdb8a | 31 | #include "alloc-util.h" |
3ffd4af2 | 32 | #include "fd-util.h" |
93cc7779 | 33 | #include "macro.h" |
3ffd4af2 | 34 | #include "memfd-util.h" |
07630cea LP |
35 | #include "missing.h" |
36 | #include "string-util.h" | |
37 | #include "utf8.h" | |
ddeb4241 | 38 | |
4531a9bc | 39 | int memfd_new(const char *name) { |
7f96b1d8 | 40 | _cleanup_free_ char *g = NULL; |
4531a9bc | 41 | int fd; |
ddeb4241 | 42 | |
5755381f | 43 | if (!name) { |
7f96b1d8 LP |
44 | char pr[17] = {}; |
45 | ||
46 | /* If no name is specified we generate one. We include | |
47 | * a hint indicating our library implementation, and | |
48 | * add the thread name to it */ | |
49 | ||
50 | assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0); | |
51 | ||
52 | if (isempty(pr)) | |
53 | name = "sd"; | |
54 | else { | |
5755381f LP |
55 | _cleanup_free_ char *e = NULL; |
56 | ||
57 | e = utf8_escape_invalid(pr); | |
58 | if (!e) | |
59 | return -ENOMEM; | |
60 | ||
61 | g = strappend("sd-", e); | |
7f96b1d8 LP |
62 | if (!g) |
63 | return -ENOMEM; | |
64 | ||
65 | name = g; | |
66 | } | |
67 | } | |
68 | ||
45071fca | 69 | fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); |
4531a9bc | 70 | if (fd < 0) |
a6082d77 | 71 | return -errno; |
ddeb4241 | 72 | |
4531a9bc | 73 | return fd; |
ddeb4241 LP |
74 | } |
75 | ||
fac9c0d5 | 76 | int memfd_map(int fd, uint64_t offset, size_t size, void **p) { |
ddeb4241 LP |
77 | void *q; |
78 | int sealed; | |
79 | ||
4531a9bc LP |
80 | assert(fd >= 0); |
81 | assert(size > 0); | |
82 | assert(p); | |
ddeb4241 | 83 | |
fac9c0d5 | 84 | sealed = memfd_get_sealed(fd); |
ddeb4241 LP |
85 | if (sealed < 0) |
86 | return sealed; | |
87 | ||
23972f42 | 88 | if (sealed) |
fac9c0d5 | 89 | q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset); |
23972f42 | 90 | else |
fac9c0d5 | 91 | q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset); |
23972f42 | 92 | |
ddeb4241 LP |
93 | if (q == MAP_FAILED) |
94 | return -errno; | |
95 | ||
96 | *p = q; | |
97 | return 0; | |
98 | } | |
99 | ||
fac9c0d5 | 100 | int memfd_set_sealed(int fd) { |
ddeb4241 LP |
101 | int r; |
102 | ||
4531a9bc | 103 | assert(fd >= 0); |
ddeb4241 | 104 | |
db74cc0d | 105 | r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
106 | if (r < 0) |
107 | return -errno; | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
fac9c0d5 | 112 | int memfd_get_sealed(int fd) { |
a6082d77 | 113 | int r; |
ddeb4241 | 114 | |
4531a9bc | 115 | assert(fd >= 0); |
ddeb4241 | 116 | |
fac9c0d5 | 117 | r = fcntl(fd, F_GET_SEALS); |
ddeb4241 LP |
118 | if (r < 0) |
119 | return -errno; | |
120 | ||
db74cc0d | 121 | return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
122 | } |
123 | ||
fac9c0d5 | 124 | int memfd_get_size(int fd, uint64_t *sz) { |
a6082d77 | 125 | struct stat stat; |
4531a9bc | 126 | int r; |
ddeb4241 | 127 | |
4531a9bc LP |
128 | assert(fd >= 0); |
129 | assert(sz); | |
ddeb4241 | 130 | |
fac9c0d5 | 131 | r = fstat(fd, &stat); |
ddeb4241 LP |
132 | if (r < 0) |
133 | return -errno; | |
134 | ||
a6082d77 | 135 | *sz = stat.st_size; |
5755381f | 136 | return 0; |
ddeb4241 LP |
137 | } |
138 | ||
fac9c0d5 | 139 | int memfd_set_size(int fd, uint64_t sz) { |
ddeb4241 LP |
140 | int r; |
141 | ||
4531a9bc | 142 | assert(fd >= 0); |
ddeb4241 | 143 | |
fac9c0d5 | 144 | r = ftruncate(fd, sz); |
ddeb4241 LP |
145 | if (r < 0) |
146 | return -errno; | |
147 | ||
5755381f | 148 | return 0; |
ddeb4241 | 149 | } |
453a0c29 | 150 | |
4531a9bc LP |
151 | int memfd_new_and_map(const char *name, size_t sz, void **p) { |
152 | _cleanup_close_ int fd = -1; | |
453a0c29 LP |
153 | int r; |
154 | ||
4531a9bc LP |
155 | assert(sz > 0); |
156 | assert(p); | |
157 | ||
158 | fd = memfd_new(name); | |
159 | if (fd < 0) | |
160 | return fd; | |
453a0c29 | 161 | |
4531a9bc | 162 | r = memfd_set_size(fd, sz); |
8a02deca | 163 | if (r < 0) |
453a0c29 | 164 | return r; |
453a0c29 | 165 | |
4531a9bc | 166 | r = memfd_map(fd, 0, sz, p); |
8a02deca | 167 | if (r < 0) |
453a0c29 | 168 | return r; |
453a0c29 | 169 | |
4531a9bc LP |
170 | r = fd; |
171 | fd = -1; | |
172 | ||
173 | return r; | |
453a0c29 | 174 | } |