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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 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 "util.h" | |
23 | #include "uid-range.h" | |
24 | ||
25 | static bool uid_range_intersect(UidRange *range, uid_t start, uid_t nr) { | |
26 | assert(range); | |
27 | ||
28 | return range->start <= start + nr && | |
29 | range->start + range->nr >= start; | |
30 | } | |
31 | ||
32 | static void uid_range_coalesce(UidRange **p, unsigned *n) { | |
33 | unsigned i, j; | |
34 | ||
35 | assert(p); | |
36 | assert(n); | |
37 | ||
38 | for (i = 0; i < *n; i++) { | |
39 | for (j = i + 1; j < *n; j++) { | |
40 | UidRange *x = (*p)+i, *y = (*p)+j; | |
41 | ||
42 | if (uid_range_intersect(x, y->start, y->nr)) { | |
43 | uid_t begin, end; | |
44 | ||
45 | begin = MIN(x->start, y->start); | |
46 | end = MAX(x->start + x->nr, y->start + y->nr); | |
47 | ||
48 | x->start = begin; | |
49 | x->nr = end - begin; | |
50 | ||
51 | if (*n > j+1) | |
52 | memmove(y, y+1, sizeof(UidRange) * (*n - j -1)); | |
53 | ||
54 | (*n) --; | |
55 | j--; | |
56 | } | |
57 | } | |
58 | } | |
59 | ||
60 | } | |
61 | ||
62 | static int uid_range_compare(const void *a, const void *b) { | |
63 | const UidRange *x = a, *y = b; | |
64 | ||
65 | if (x->start < y->start) | |
66 | return -1; | |
67 | if (x->start > y->start) | |
68 | return 1; | |
69 | ||
70 | if (x->nr < y->nr) | |
71 | return -1; | |
72 | if (x->nr > y->nr) | |
73 | return 1; | |
74 | ||
75 | return 0; | |
76 | } | |
77 | ||
78 | int uid_range_add(UidRange **p, unsigned *n, uid_t start, uid_t nr) { | |
79 | bool found = false; | |
80 | UidRange *x; | |
81 | unsigned i; | |
82 | ||
83 | assert(p); | |
84 | assert(n); | |
85 | ||
86 | if (nr <= 0) | |
87 | return 0; | |
88 | ||
89 | for (i = 0; i < *n; i++) { | |
90 | x = (*p) + i; | |
91 | if (uid_range_intersect(x, start, nr)) { | |
92 | found = true; | |
93 | break; | |
94 | } | |
95 | } | |
96 | ||
97 | if (found) { | |
98 | uid_t begin, end; | |
99 | ||
100 | begin = MIN(x->start, start); | |
101 | end = MAX(x->start + x->nr, start + nr); | |
102 | ||
103 | x->start = begin; | |
104 | x->nr = end - begin; | |
105 | } else { | |
106 | UidRange *t; | |
107 | ||
108 | t = realloc(*p, sizeof(UidRange) * (*n + 1)); | |
109 | if (!t) | |
110 | return -ENOMEM; | |
111 | ||
112 | *p = t; | |
113 | x = t + ((*n) ++); | |
114 | ||
115 | x->start = start; | |
116 | x->nr = nr; | |
117 | } | |
118 | ||
119 | qsort(*p, *n, sizeof(UidRange), uid_range_compare); | |
120 | uid_range_coalesce(p, n); | |
121 | ||
122 | return *n; | |
123 | } | |
124 | ||
125 | int uid_range_add_str(UidRange **p, unsigned *n, const char *s) { | |
126 | uid_t start, nr; | |
127 | const char *t; | |
128 | int r; | |
129 | ||
130 | assert(p); | |
131 | assert(n); | |
132 | assert(s); | |
133 | ||
134 | t = strchr(s, '-'); | |
135 | if (t) { | |
136 | char *b; | |
137 | uid_t end; | |
138 | ||
139 | b = strndupa(s, t - s); | |
140 | r = parse_uid(b, &start); | |
141 | if (r < 0) | |
142 | return r; | |
143 | ||
144 | r = parse_uid(t+1, &end); | |
145 | if (r < 0) | |
146 | return r; | |
147 | ||
148 | if (end < start) | |
149 | return -EINVAL; | |
150 | ||
151 | nr = end - start + 1; | |
152 | } else { | |
153 | r = parse_uid(s, &start); | |
154 | if (r < 0) | |
155 | return r; | |
156 | ||
157 | nr = 1; | |
158 | } | |
159 | ||
160 | return uid_range_add(p, n, start, nr); | |
161 | } | |
162 | ||
163 | int uid_range_next_lower(const UidRange *p, unsigned n, uid_t *uid) { | |
fed1e721 | 164 | uid_t closest = UID_INVALID, candidate; |
8530dc44 LP |
165 | unsigned i; |
166 | ||
167 | assert(p); | |
168 | assert(uid); | |
169 | ||
170 | candidate = *uid - 1; | |
171 | ||
172 | for (i = 0; i < n; i++) { | |
173 | uid_t begin, end; | |
174 | ||
175 | begin = p[i].start; | |
176 | end = p[i].start + p[i].nr - 1; | |
177 | ||
178 | if (candidate >= begin && candidate <= end) { | |
179 | *uid = candidate; | |
180 | return 1; | |
181 | } | |
182 | ||
183 | if (end < candidate) | |
184 | closest = end; | |
185 | } | |
186 | ||
fed1e721 | 187 | if (closest == UID_INVALID) |
8530dc44 LP |
188 | return -EBUSY; |
189 | ||
190 | *uid = closest; | |
191 | return 1; | |
192 | } | |
193 | ||
194 | bool uid_range_contains(const UidRange *p, unsigned n, uid_t uid) { | |
195 | unsigned i; | |
196 | ||
197 | assert(p); | |
198 | assert(uid); | |
199 | ||
200 | for (i = 0; i < n; i++) | |
201 | if (uid >= p[i].start && uid < p[i].start + p[i].nr) | |
202 | return true; | |
203 | ||
204 | return false; | |
205 | } |