204 lines
6.3 KiB
C
204 lines
6.3 KiB
C
/*
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* Copyright (c) 1991 - 1994, Julianne Frances Haugh
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* Copyright (c) 2008 - 2009, Nicolas François
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the copyright holders or contributors may not be used to
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* endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <config.h>
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#include <assert.h>
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#include <stdio.h>
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#include <errno.h>
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#include "prototypes.h"
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#include "groupio.h"
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#include "getdef.h"
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/*
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* find_new_gid - Find a new unused GID.
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*
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* If successful, find_new_gid provides an unused group ID in the
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* [GID_MIN:GID_MAX] range.
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* This ID should be higher than all the used GID, but if not possible,
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* the lowest unused ID in the range will be returned.
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*
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* Return 0 on success, -1 if no unused GIDs are available.
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*/
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int find_new_gid (bool sys_group,
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gid_t *gid,
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/*@null@*/gid_t const *preferred_gid)
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{
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const struct group *grp;
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gid_t gid_min, gid_max, group_id;
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bool *used_gids;
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assert (gid != NULL);
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if (!sys_group) {
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gid_min = (gid_t) getdef_ulong ("GID_MIN", 1000UL);
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gid_max = (gid_t) getdef_ulong ("GID_MAX", 60000UL);
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if (gid_max < gid_min) {
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(void) fprintf (stderr,
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_("%s: Invalid configuration: GID_MIN (%lu), GID_MAX (%lu)\n"),
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Prog, (unsigned long) gid_min, (unsigned long) gid_max);
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}
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} else {
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gid_min = (gid_t) getdef_ulong ("SYS_GID_MIN", 101UL);
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gid_max = (gid_t) getdef_ulong ("GID_MIN", 1000UL) - 1;
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gid_max = (gid_t) getdef_ulong ("SYS_GID_MAX", (unsigned long) gid_max);
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if (gid_max < gid_min) {
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(void) fprintf (stderr,
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_("%s: Invalid configuration: SYS_GID_MIN (%lu), GID_MIN (%lu), SYS_GID_MAX (%lu)\n"),
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Prog, (unsigned long) gid_min, getdef_ulong ("GID_MIN", 1000UL), (unsigned long) gid_max);
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}
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}
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used_gids = malloc (sizeof (bool) * (gid_max +1));
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if (NULL == used_gids) {
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fprintf (stderr,
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_("%s: failed to allocate memory: %s\n"),
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Prog, strerror (errno));
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return -1;
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}
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memset (used_gids, false, sizeof (bool) * (gid_max + 1));
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if ( (NULL != preferred_gid)
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&& (*preferred_gid >= gid_min)
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&& (*preferred_gid <= gid_max)
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/* Check if the user exists according to NSS */
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&& (getgrgid (*preferred_gid) == NULL)
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/* Check also the local database in case of uncommitted
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* changes */
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&& (gr_locate_gid (*preferred_gid) == NULL)) {
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*gid = *preferred_gid;
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return 0;
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}
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/*
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* Search the entire group file,
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* looking for the largest unused value.
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*
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* We check the list of groups according to NSS (setgrent/getgrent),
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* but we also check the local database (gr_rewind/gr_next) in case
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* some groups were created but the changes were not committed yet.
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*/
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if (sys_group) {
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gid_t id;
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/* setgrent / getgrent / endgrent can be very slow with
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* LDAP configurations (and many accounts).
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* Since there is a limited amount of IDs to be tested
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* for system accounts, we just check the existence
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* of IDs with getgrgid.
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*/
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group_id = gid_max;
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for (id = gid_max; id >= gid_min; id--) {
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if (getgrgid (id) != NULL) {
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group_id = id - 1;
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used_gids[id] = true;
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}
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}
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(void) gr_rewind ();
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while ((grp = gr_next ()) != NULL) {
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if ((grp->gr_gid <= group_id) && (grp->gr_gid >= gid_min)) {
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group_id = grp->gr_gid - 1;
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}
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/* create index of used GIDs */
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if (grp->gr_gid <= gid_max) {
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used_gids[grp->gr_gid] = true;
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}
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}
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} else {
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group_id = gid_min;
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setgrent ();
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while ((grp = getgrent ()) != NULL) {
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if ((grp->gr_gid >= group_id) && (grp->gr_gid <= gid_max)) {
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group_id = grp->gr_gid + 1;
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}
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/* create index of used GIDs */
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if (grp->gr_gid <= gid_max) {
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used_gids[grp->gr_gid] = true;
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}
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}
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endgrent ();
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(void) gr_rewind ();
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while ((grp = gr_next ()) != NULL) {
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if ((grp->gr_gid >= group_id) && (grp->gr_gid <= gid_max)) {
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group_id = grp->gr_gid + 1;
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}
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/* create index of used GIDs */
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if (grp->gr_gid <= gid_max) {
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used_gids[grp->gr_gid] = true;
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}
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}
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}
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/*
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* If a group with GID equal to GID_MAX exists, the above algorithm
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* will give us GID_MAX+1 even if not unique. Search for the first
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* free GID starting with GID_MIN.
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*/
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if (sys_group) {
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if (group_id == gid_min - 1) {
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for (group_id = gid_max; group_id >= gid_min; group_id--) {
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if (false == used_gids[group_id]) {
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break;
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}
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}
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if ( group_id < gid_min ) {
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fprintf (stderr,
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_("%s: Can't get unique system GID (no more available GIDs)\n"),
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Prog);
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SYSLOG ((LOG_WARN,
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"no more available GID on the system"));
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return -1;
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}
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}
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} else {
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if (group_id == gid_max + 1) {
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for (group_id = gid_min; group_id < gid_max; group_id++) {
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if (false == used_gids[group_id]) {
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break;
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}
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}
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if (group_id == gid_max) {
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fprintf (stderr,
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_("%s: Can't get unique GID (no more available GIDs)\n"),
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Prog);
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SYSLOG ((LOG_WARN, "no more available GID on the system"));
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return -1;
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}
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}
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}
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free (used_gids);
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*gid = group_id;
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return 0;
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}
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