shadow/libmisc/find_new_sub_uids.c

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/*
* SPDX-FileCopyrightText: 2012 Eric Biederman
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ifdef ENABLE_SUBIDS
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include "prototypes.h"
#include "subordinateio.h"
#include "getdef.h"
#include "shadowlog.h"
/*
* find_new_sub_uids - Find a new unused range of UIDs.
*
* If successful, find_new_sub_uids provides a range of unused
* user IDs in the [SUB_UID_MIN:SUB_UID_MAX] range.
2021-08-18 23:36:02 +05:30
*
* Return 0 on success, -1 if no unused UIDs are available.
*/
int find_new_sub_uids (uid_t *range_start, unsigned long *range_count)
{
unsigned long min, max;
unsigned long count;
uid_t start;
assert (range_start != NULL);
assert (range_count != NULL);
min = getdef_ulong ("SUB_UID_MIN", 100000UL);
max = getdef_ulong ("SUB_UID_MAX", 600100000UL);
count = getdef_ulong ("SUB_UID_COUNT", 65536);
if (min > max || count >= max || (min + count - 1) > max) {
(void) fprintf (log_get_logfd(),
_("%s: Invalid configuration: SUB_UID_MIN (%lu),"
" SUB_UID_MAX (%lu), SUB_UID_COUNT (%lu)\n"),
log_get_progname(), min, max, count);
return -1;
}
start = sub_uid_find_free_range(min, max, count);
if (start == (uid_t)-1) {
fprintf (log_get_logfd(),
_("%s: Can't get unique subordinate UID range\n"),
log_get_progname());
SYSLOG ((LOG_WARN, "no more available subordinate UIDs on the system"));
return -1;
}
*range_start = start;
*range_count = count;
return 0;
}
#else /* !ENABLE_SUBIDS */
extern int ISO_C_forbids_an_empty_translation_unit;
#endif /* !ENABLE_SUBIDS */