diff options
Diffstat (limited to 'src/libsystemd-shared/src/uid-range.c')
| -rw-r--r-- | src/libsystemd-shared/src/uid-range.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/libsystemd-shared/src/uid-range.c b/src/libsystemd-shared/src/uid-range.c new file mode 100644 index 0000000000..ec08299d02 --- /dev/null +++ b/src/libsystemd-shared/src/uid-range.c @@ -0,0 +1,208 @@ +/*** + This file is part of systemd. + + Copyright 2014 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <stdlib.h> +#include <string.h> + +#include "systemd-basic/macro.h" +#include "systemd-basic/user-util.h" +#include "systemd-shared/uid-range.h" + +static bool uid_range_intersect(UidRange *range, uid_t start, uid_t nr) { + assert(range); + + return range->start <= start + nr && + range->start + range->nr >= start; +} + +static void uid_range_coalesce(UidRange **p, unsigned *n) { + unsigned i, j; + + assert(p); + assert(n); + + for (i = 0; i < *n; i++) { + for (j = i + 1; j < *n; j++) { + UidRange *x = (*p)+i, *y = (*p)+j; + + if (uid_range_intersect(x, y->start, y->nr)) { + uid_t begin, end; + + begin = MIN(x->start, y->start); + end = MAX(x->start + x->nr, y->start + y->nr); + + x->start = begin; + x->nr = end - begin; + + if (*n > j+1) + memmove(y, y+1, sizeof(UidRange) * (*n - j -1)); + + (*n)--; + j--; + } + } + } + +} + +static int uid_range_compare(const void *a, const void *b) { + const UidRange *x = a, *y = b; + + if (x->start < y->start) + return -1; + if (x->start > y->start) + return 1; + + if (x->nr < y->nr) + return -1; + if (x->nr > y->nr) + return 1; + + return 0; +} + +int uid_range_add(UidRange **p, unsigned *n, uid_t start, uid_t nr) { + bool found = false; + UidRange *x; + unsigned i; + + assert(p); + assert(n); + + if (nr <= 0) + return 0; + + for (i = 0; i < *n; i++) { + x = (*p) + i; + if (uid_range_intersect(x, start, nr)) { + found = true; + break; + } + } + + if (found) { + uid_t begin, end; + + begin = MIN(x->start, start); + end = MAX(x->start + x->nr, start + nr); + + x->start = begin; + x->nr = end - begin; + } else { + UidRange *t; + + t = realloc(*p, sizeof(UidRange) * (*n + 1)); + if (!t) + return -ENOMEM; + + *p = t; + x = t + ((*n) ++); + + x->start = start; + x->nr = nr; + } + + qsort(*p, *n, sizeof(UidRange), uid_range_compare); + uid_range_coalesce(p, n); + + return *n; +} + +int uid_range_add_str(UidRange **p, unsigned *n, const char *s) { + uid_t start, nr; + const char *t; + int r; + + assert(p); + assert(n); + assert(s); + + t = strchr(s, '-'); + if (t) { + char *b; + uid_t end; + + b = strndupa(s, t - s); + r = parse_uid(b, &start); + if (r < 0) + return r; + + r = parse_uid(t+1, &end); + if (r < 0) + return r; + + if (end < start) + return -EINVAL; + + nr = end - start + 1; + } else { + r = parse_uid(s, &start); + if (r < 0) + return r; + + nr = 1; + } + + return uid_range_add(p, n, start, nr); +} + +int uid_range_next_lower(const UidRange *p, unsigned n, uid_t *uid) { + uid_t closest = UID_INVALID, candidate; + unsigned i; + + assert(p); + assert(uid); + + candidate = *uid - 1; + + for (i = 0; i < n; i++) { + uid_t begin, end; + + begin = p[i].start; + end = p[i].start + p[i].nr - 1; + + if (candidate >= begin && candidate <= end) { + *uid = candidate; + return 1; + } + + if (end < candidate) + closest = end; + } + + if (closest == UID_INVALID) + return -EBUSY; + + *uid = closest; + return 1; +} + +bool uid_range_contains(const UidRange *p, unsigned n, uid_t uid) { + unsigned i; + + assert(p); + assert(uid); + + for (i = 0; i < n; i++) + if (uid >= p[i].start && uid < p[i].start + p[i].nr) + return true; + + return false; +} |