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