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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
***/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "alloc-util.h"
#include "macro.h"
#include "uid-range.h"
#include "user-util.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 = reallocarray(*p, *n + 1, sizeof(UidRange));
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;
}
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