summaryrefslogtreecommitdiff
path: root/src/libelogind/sd-id128/id128-util.c
blob: e6e20234088cbd5779ef9f1596fda854d851d145 (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
/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  Copyright 2016 Lennart Poettering
***/

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include "fd-util.h"
#include "fs-util.h"
#include "hexdecoct.h"
#include "id128-util.h"
#include "io-util.h"
#include "stdio-util.h"

char *id128_to_uuid_string(sd_id128_t id, char s[37]) {
        unsigned n, k = 0;

        assert(s);

        /* Similar to sd_id128_to_string() but formats the result as UUID instead of plain hex chars */

        for (n = 0; n < 16; n++) {

                if (IN_SET(n, 4, 6, 8, 10))
                        s[k++] = '-';

                s[k++] = hexchar(id.bytes[n] >> 4);
                s[k++] = hexchar(id.bytes[n] & 0xF);
        }

        assert(k == 36);

        s[k] = 0;

        return s;
}

bool id128_is_valid(const char *s) {
        size_t i, l;

        assert(s);

        l = strlen(s);
        if (l == 32) {

                /* Plain formatted 128bit hex string */

                for (i = 0; i < l; i++) {
                        char c = s[i];

                        if (!(c >= '0' && c <= '9') &&
                            !(c >= 'a' && c <= 'z') &&
                            !(c >= 'A' && c <= 'Z'))
                                return false;
                }

        } else if (l == 36) {

                /* Formatted UUID */

                for (i = 0; i < l; i++) {
                        char c = s[i];

                        if (IN_SET(i, 8, 13, 18, 23)) {
                                if (c != '-')
                                        return false;
                        } else {
                                if (!(c >= '0' && c <= '9') &&
                                    !(c >= 'a' && c <= 'z') &&
                                    !(c >= 'A' && c <= 'Z'))
                                        return false;
                        }
                }

        } else
                return false;

        return true;
}

int id128_read_fd(int fd, Id128Format f, sd_id128_t *ret) {
        char buffer[36 + 2];
        ssize_t l;

        assert(fd >= 0);
        assert(f < _ID128_FORMAT_MAX);

        /* Reads an 128bit ID from a file, which may either be in plain format (32 hex digits), or in UUID format, both
         * optionally followed by a newline and nothing else. ID files should really be newline terminated, but if they
         * aren't that's OK too, following the rule of "Be conservative in what you send, be liberal in what you
         * accept". */

        l = loop_read(fd, buffer, sizeof(buffer), false); /* we expect a short read of either 32/33 or 36/37 chars */
        if (l < 0)
                return (int) l;
        if (l == 0) /* empty? */
                return -ENOMEDIUM;

        switch (l) {

        case 33: /* plain UUID with trailing newline */
                if (buffer[32] != '\n')
                        return -EINVAL;

                _fallthrough_;
        case 32: /* plain UUID without trailing newline */
                if (f == ID128_UUID)
                        return -EINVAL;

                buffer[32] = 0;
                break;

        case 37: /* RFC UUID with trailing newline */
                if (buffer[36] != '\n')
                        return -EINVAL;

                _fallthrough_;
        case 36: /* RFC UUID without trailing newline */
                if (f == ID128_PLAIN)
                        return -EINVAL;

                buffer[36] = 0;
                break;

        default:
                return -EINVAL;
        }

        return sd_id128_from_string(buffer, ret);
}

int id128_read(const char *p, Id128Format f, sd_id128_t *ret) {
        _cleanup_close_ int fd = -1;

        fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
        if (fd < 0)
                return -errno;

        return id128_read_fd(fd, f, ret);
}

int id128_write_fd(int fd, Id128Format f, sd_id128_t id, bool do_sync) {
        char buffer[36 + 2];
        size_t sz;
        int r;

        assert(fd >= 0);
        assert(f < _ID128_FORMAT_MAX);

        if (f != ID128_UUID) {
                sd_id128_to_string(id, buffer);
                buffer[32] = '\n';
                sz = 33;
        } else {
                id128_to_uuid_string(id, buffer);
                buffer[36] = '\n';
                sz = 37;
        }

        r = loop_write(fd, buffer, sz, false);
        if (r < 0)
                return r;

        if (do_sync) {
                if (fsync(fd) < 0)
                        return -errno;

                r = fsync_directory_of_file(fd);
                if (r < 0)
                        return r;
        }

        return 0;
}

#if 0 /// UNNEEDED by elogind
int id128_write(const char *p, Id128Format f, sd_id128_t id, bool do_sync) {
        _cleanup_close_ int fd = -1;

        fd = open(p, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY|O_TRUNC, 0444);
        if (fd < 0)
                return -errno;

        return id128_write_fd(fd, f, id, do_sync);
}

void id128_hash_func(const void *p, struct siphash *state) {
        siphash24_compress(p, 16, state);
}

int id128_compare_func(const void *a, const void *b) {
        return memcmp(a, b, 16);
}

const struct hash_ops id128_hash_ops = {
        .hash = id128_hash_func,
        .compare = id128_compare_func,
};
#endif // 0