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6e6fb527 LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2012 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 TA |
20 | #include <errno.h> |
21 | #include <stddef.h> | |
22 | #include <stdlib.h> | |
6e6fb527 LP |
23 | #include <string.h> |
24 | ||
b5efdb8a | 25 | #include "alloc-util.h" |
6e6fb527 | 26 | #include "macro.h" |
6e6fb527 | 27 | #include "replace-var.h" |
b11d6a7b | 28 | #include "string-util.h" |
6e6fb527 LP |
29 | |
30 | /* | |
31 | * Generic infrastructure for replacing @FOO@ style variables in | |
32 | * strings. Will call a callback for each replacement. | |
33 | */ | |
34 | ||
35 | static int get_variable(const char *b, char **r) { | |
36 | size_t k; | |
37 | char *t; | |
38 | ||
39 | assert(b); | |
40 | assert(r); | |
41 | ||
42 | if (*b != '@') | |
43 | return 0; | |
44 | ||
4b549144 | 45 | k = strspn(b + 1, UPPERCASE_LETTERS "_"); |
6e6fb527 LP |
46 | if (k <= 0 || b[k+1] != '@') |
47 | return 0; | |
48 | ||
49 | t = strndup(b + 1, k); | |
50 | if (!t) | |
51 | return -ENOMEM; | |
52 | ||
53 | *r = t; | |
54 | return 1; | |
55 | } | |
56 | ||
57 | char *replace_var(const char *text, char *(*lookup)(const char *variable, void*userdata), void *userdata) { | |
58 | char *r, *t; | |
59 | const char *f; | |
60 | size_t l; | |
61 | ||
62 | assert(text); | |
63 | assert(lookup); | |
64 | ||
65 | l = strlen(text); | |
66 | r = new(char, l+1); | |
67 | if (!r) | |
68 | return NULL; | |
69 | ||
70 | f = text; | |
71 | t = r; | |
72 | while (*f) { | |
73 | _cleanup_free_ char *v = NULL, *n = NULL; | |
74 | char *a; | |
75 | int k; | |
76 | size_t skip, d, nl; | |
77 | ||
78 | k = get_variable(f, &v); | |
79 | if (k < 0) | |
80 | goto oom; | |
81 | if (k == 0) { | |
82 | *(t++) = *(f++); | |
83 | continue; | |
84 | } | |
85 | ||
86 | n = lookup(v, userdata); | |
87 | if (!n) | |
88 | goto oom; | |
89 | ||
90 | skip = strlen(v) + 2; | |
91 | ||
92 | d = t - r; | |
93 | nl = l - skip + strlen(n); | |
94 | a = realloc(r, nl + 1); | |
95 | if (!a) | |
96 | goto oom; | |
97 | ||
98 | l = nl; | |
99 | r = a; | |
100 | t = r + d; | |
101 | ||
102 | t = stpcpy(t, n); | |
103 | f += skip; | |
104 | } | |
105 | ||
106 | *t = 0; | |
107 | return r; | |
108 | ||
109 | oom: | |
6b430fdb | 110 | return mfree(r); |
6e6fb527 | 111 | } |