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ddeb4241 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2013 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <stdio.h> | |
23 | #include <fcntl.h> | |
ddeb4241 | 24 | #include <sys/mman.h> |
7f96b1d8 | 25 | #include <sys/prctl.h> |
ddeb4241 | 26 | |
27c64db6 ZJS |
27 | #ifdef HAVE_LINUX_MEMFD_H |
28 | # include <linux/memfd.h> | |
29 | #endif | |
30 | ||
ddeb4241 | 31 | #include "util.h" |
a09abc4a | 32 | #include "memfd-util.h" |
8f2807ba | 33 | #include "utf8.h" |
27c64db6 | 34 | #include "missing.h" |
ddeb4241 | 35 | |
4531a9bc | 36 | int memfd_new(const char *name) { |
7f96b1d8 | 37 | _cleanup_free_ char *g = NULL; |
4531a9bc | 38 | int fd; |
ddeb4241 | 39 | |
5755381f | 40 | if (!name) { |
7f96b1d8 LP |
41 | char pr[17] = {}; |
42 | ||
43 | /* If no name is specified we generate one. We include | |
44 | * a hint indicating our library implementation, and | |
45 | * add the thread name to it */ | |
46 | ||
47 | assert_se(prctl(PR_GET_NAME, (unsigned long) pr) >= 0); | |
48 | ||
49 | if (isempty(pr)) | |
50 | name = "sd"; | |
51 | else { | |
5755381f LP |
52 | _cleanup_free_ char *e = NULL; |
53 | ||
54 | e = utf8_escape_invalid(pr); | |
55 | if (!e) | |
56 | return -ENOMEM; | |
57 | ||
58 | g = strappend("sd-", e); | |
7f96b1d8 LP |
59 | if (!g) |
60 | return -ENOMEM; | |
61 | ||
62 | name = g; | |
63 | } | |
64 | } | |
65 | ||
45071fca | 66 | fd = memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC); |
4531a9bc | 67 | if (fd < 0) |
a6082d77 | 68 | return -errno; |
ddeb4241 | 69 | |
4531a9bc | 70 | return fd; |
ddeb4241 LP |
71 | } |
72 | ||
fac9c0d5 | 73 | int memfd_map(int fd, uint64_t offset, size_t size, void **p) { |
ddeb4241 LP |
74 | void *q; |
75 | int sealed; | |
76 | ||
4531a9bc LP |
77 | assert(fd >= 0); |
78 | assert(size > 0); | |
79 | assert(p); | |
ddeb4241 | 80 | |
fac9c0d5 | 81 | sealed = memfd_get_sealed(fd); |
ddeb4241 LP |
82 | if (sealed < 0) |
83 | return sealed; | |
84 | ||
23972f42 | 85 | if (sealed) |
fac9c0d5 | 86 | q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, offset); |
23972f42 | 87 | else |
fac9c0d5 | 88 | q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset); |
23972f42 | 89 | |
ddeb4241 LP |
90 | if (q == MAP_FAILED) |
91 | return -errno; | |
92 | ||
93 | *p = q; | |
94 | return 0; | |
95 | } | |
96 | ||
fac9c0d5 | 97 | int memfd_set_sealed(int fd) { |
ddeb4241 LP |
98 | int r; |
99 | ||
4531a9bc | 100 | assert(fd >= 0); |
ddeb4241 | 101 | |
db74cc0d | 102 | r = fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
103 | if (r < 0) |
104 | return -errno; | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
fac9c0d5 | 109 | int memfd_get_sealed(int fd) { |
a6082d77 | 110 | int r; |
ddeb4241 | 111 | |
4531a9bc | 112 | assert(fd >= 0); |
ddeb4241 | 113 | |
fac9c0d5 | 114 | r = fcntl(fd, F_GET_SEALS); |
ddeb4241 LP |
115 | if (r < 0) |
116 | return -errno; | |
117 | ||
db74cc0d | 118 | return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); |
ddeb4241 LP |
119 | } |
120 | ||
fac9c0d5 | 121 | int memfd_get_size(int fd, uint64_t *sz) { |
a6082d77 | 122 | struct stat stat; |
4531a9bc | 123 | int r; |
ddeb4241 | 124 | |
4531a9bc LP |
125 | assert(fd >= 0); |
126 | assert(sz); | |
ddeb4241 | 127 | |
fac9c0d5 | 128 | r = fstat(fd, &stat); |
ddeb4241 LP |
129 | if (r < 0) |
130 | return -errno; | |
131 | ||
a6082d77 | 132 | *sz = stat.st_size; |
5755381f | 133 | return 0; |
ddeb4241 LP |
134 | } |
135 | ||
fac9c0d5 | 136 | int memfd_set_size(int fd, uint64_t sz) { |
ddeb4241 LP |
137 | int r; |
138 | ||
4531a9bc | 139 | assert(fd >= 0); |
ddeb4241 | 140 | |
fac9c0d5 | 141 | r = ftruncate(fd, sz); |
ddeb4241 LP |
142 | if (r < 0) |
143 | return -errno; | |
144 | ||
5755381f | 145 | return 0; |
ddeb4241 | 146 | } |
453a0c29 | 147 | |
4531a9bc LP |
148 | int memfd_new_and_map(const char *name, size_t sz, void **p) { |
149 | _cleanup_close_ int fd = -1; | |
453a0c29 LP |
150 | int r; |
151 | ||
4531a9bc LP |
152 | assert(sz > 0); |
153 | assert(p); | |
154 | ||
155 | fd = memfd_new(name); | |
156 | if (fd < 0) | |
157 | return fd; | |
453a0c29 | 158 | |
4531a9bc | 159 | r = memfd_set_size(fd, sz); |
8a02deca | 160 | if (r < 0) |
453a0c29 | 161 | return r; |
453a0c29 | 162 | |
4531a9bc | 163 | r = memfd_map(fd, 0, sz, p); |
8a02deca | 164 | if (r < 0) |
453a0c29 | 165 | return r; |
453a0c29 | 166 | |
4531a9bc LP |
167 | r = fd; |
168 | fd = -1; | |
169 | ||
170 | return r; | |
453a0c29 | 171 | } |