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8530dc44 LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2014 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 | ||
a8fbdf54 TA |
20 | #include <errno.h> |
21 | #include <stdlib.h> | |
22 | #include <string.h> | |
23 | ||
24 | #include "macro.h" | |
8530dc44 | 25 | #include "uid-range.h" |
b1d4f8e1 | 26 | #include "user-util.h" |
8530dc44 LP |
27 | |
28 | static bool uid_range_intersect(UidRange *range, uid_t start, uid_t nr) { | |
29 | assert(range); | |
30 | ||
31 | return range->start <= start + nr && | |
32 | range->start + range->nr >= start; | |
33 | } | |
34 | ||
35 | static void uid_range_coalesce(UidRange **p, unsigned *n) { | |
36 | unsigned i, j; | |
37 | ||
38 | assert(p); | |
39 | assert(n); | |
40 | ||
41 | for (i = 0; i < *n; i++) { | |
42 | for (j = i + 1; j < *n; j++) { | |
43 | UidRange *x = (*p)+i, *y = (*p)+j; | |
44 | ||
45 | if (uid_range_intersect(x, y->start, y->nr)) { | |
46 | uid_t begin, end; | |
47 | ||
48 | begin = MIN(x->start, y->start); | |
49 | end = MAX(x->start + x->nr, y->start + y->nr); | |
50 | ||
51 | x->start = begin; | |
52 | x->nr = end - begin; | |
53 | ||
54 | if (*n > j+1) | |
55 | memmove(y, y+1, sizeof(UidRange) * (*n - j -1)); | |
56 | ||
313cefa1 | 57 | (*n)--; |
8530dc44 LP |
58 | j--; |
59 | } | |
60 | } | |
61 | } | |
62 | ||
63 | } | |
64 | ||
65 | static int uid_range_compare(const void *a, const void *b) { | |
66 | const UidRange *x = a, *y = b; | |
67 | ||
68 | if (x->start < y->start) | |
69 | return -1; | |
70 | if (x->start > y->start) | |
71 | return 1; | |
72 | ||
73 | if (x->nr < y->nr) | |
74 | return -1; | |
75 | if (x->nr > y->nr) | |
76 | return 1; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | int uid_range_add(UidRange **p, unsigned *n, uid_t start, uid_t nr) { | |
82 | bool found = false; | |
83 | UidRange *x; | |
84 | unsigned i; | |
85 | ||
86 | assert(p); | |
87 | assert(n); | |
88 | ||
89 | if (nr <= 0) | |
90 | return 0; | |
91 | ||
92 | for (i = 0; i < *n; i++) { | |
93 | x = (*p) + i; | |
94 | if (uid_range_intersect(x, start, nr)) { | |
95 | found = true; | |
96 | break; | |
97 | } | |
98 | } | |
99 | ||
100 | if (found) { | |
101 | uid_t begin, end; | |
102 | ||
103 | begin = MIN(x->start, start); | |
104 | end = MAX(x->start + x->nr, start + nr); | |
105 | ||
106 | x->start = begin; | |
107 | x->nr = end - begin; | |
108 | } else { | |
109 | UidRange *t; | |
110 | ||
111 | t = realloc(*p, sizeof(UidRange) * (*n + 1)); | |
112 | if (!t) | |
113 | return -ENOMEM; | |
114 | ||
115 | *p = t; | |
116 | x = t + ((*n) ++); | |
117 | ||
118 | x->start = start; | |
119 | x->nr = nr; | |
120 | } | |
121 | ||
122 | qsort(*p, *n, sizeof(UidRange), uid_range_compare); | |
123 | uid_range_coalesce(p, n); | |
124 | ||
125 | return *n; | |
126 | } | |
127 | ||
128 | int uid_range_add_str(UidRange **p, unsigned *n, const char *s) { | |
129 | uid_t start, nr; | |
130 | const char *t; | |
131 | int r; | |
132 | ||
133 | assert(p); | |
134 | assert(n); | |
135 | assert(s); | |
136 | ||
137 | t = strchr(s, '-'); | |
138 | if (t) { | |
139 | char *b; | |
140 | uid_t end; | |
141 | ||
142 | b = strndupa(s, t - s); | |
143 | r = parse_uid(b, &start); | |
144 | if (r < 0) | |
145 | return r; | |
146 | ||
147 | r = parse_uid(t+1, &end); | |
148 | if (r < 0) | |
149 | return r; | |
150 | ||
151 | if (end < start) | |
152 | return -EINVAL; | |
153 | ||
154 | nr = end - start + 1; | |
155 | } else { | |
156 | r = parse_uid(s, &start); | |
157 | if (r < 0) | |
158 | return r; | |
159 | ||
160 | nr = 1; | |
161 | } | |
162 | ||
163 | return uid_range_add(p, n, start, nr); | |
164 | } | |
165 | ||
166 | int uid_range_next_lower(const UidRange *p, unsigned n, uid_t *uid) { | |
fed1e721 | 167 | uid_t closest = UID_INVALID, candidate; |
8530dc44 LP |
168 | unsigned i; |
169 | ||
170 | assert(p); | |
171 | assert(uid); | |
172 | ||
173 | candidate = *uid - 1; | |
174 | ||
175 | for (i = 0; i < n; i++) { | |
176 | uid_t begin, end; | |
177 | ||
178 | begin = p[i].start; | |
179 | end = p[i].start + p[i].nr - 1; | |
180 | ||
181 | if (candidate >= begin && candidate <= end) { | |
182 | *uid = candidate; | |
183 | return 1; | |
184 | } | |
185 | ||
186 | if (end < candidate) | |
187 | closest = end; | |
188 | } | |
189 | ||
fed1e721 | 190 | if (closest == UID_INVALID) |
8530dc44 LP |
191 | return -EBUSY; |
192 | ||
193 | *uid = closest; | |
194 | return 1; | |
195 | } | |
196 | ||
197 | bool uid_range_contains(const UidRange *p, unsigned n, uid_t uid) { | |
198 | unsigned i; | |
199 | ||
200 | assert(p); | |
201 | assert(uid); | |
202 | ||
203 | for (i = 0; i < n; i++) | |
204 | if (uid >= p[i].start && uid < p[i].start + p[i].nr) | |
205 | return true; | |
206 | ||
207 | return false; | |
208 | } |