293 lines
8.4 KiB
C
293 lines
8.4 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2011 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <assert.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/acl.h>
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#include <acl/libacl.h>
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#include "util.h"
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#include "acl-util.h"
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#include "set.h"
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#include "logind-acl.h"
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#include "udev-util.h"
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static int flush_acl(acl_t acl) {
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acl_entry_t i;
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int found;
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bool changed = false;
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assert(acl);
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for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
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found > 0;
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found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
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acl_tag_t tag;
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if (acl_get_tag_type(i, &tag) < 0)
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return -errno;
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if (tag != ACL_USER)
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continue;
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if (acl_delete_entry(acl, i) < 0)
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return -errno;
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changed = true;
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}
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if (found < 0)
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return -errno;
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return changed;
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}
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int devnode_acl(const char *path,
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bool flush,
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bool del, uid_t old_uid,
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bool add, uid_t new_uid) {
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acl_t acl;
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int r = 0;
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bool changed = false;
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assert(path);
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acl = acl_get_file(path, ACL_TYPE_ACCESS);
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if (!acl)
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return -errno;
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if (flush) {
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r = flush_acl(acl);
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if (r < 0)
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goto finish;
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if (r > 0)
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changed = true;
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} else if (del && old_uid > 0) {
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acl_entry_t entry;
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r = acl_find_uid(acl, old_uid, &entry);
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if (r < 0)
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goto finish;
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if (r > 0) {
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if (acl_delete_entry(acl, entry) < 0) {
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r = -errno;
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goto finish;
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}
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changed = true;
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}
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}
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if (add && new_uid > 0) {
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acl_entry_t entry;
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acl_permset_t permset;
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int rd, wt;
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r = acl_find_uid(acl, new_uid, &entry);
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if (r < 0)
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goto finish;
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if (r == 0) {
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if (acl_create_entry(&acl, &entry) < 0) {
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r = -errno;
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goto finish;
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}
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if (acl_set_tag_type(entry, ACL_USER) < 0 ||
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acl_set_qualifier(entry, &new_uid) < 0) {
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r = -errno;
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goto finish;
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}
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}
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if (acl_get_permset(entry, &permset) < 0) {
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r = -errno;
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goto finish;
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}
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rd = acl_get_perm(permset, ACL_READ);
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if (rd < 0) {
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r = -errno;
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goto finish;
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}
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wt = acl_get_perm(permset, ACL_WRITE);
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if (wt < 0) {
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r = -errno;
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goto finish;
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}
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if (!rd || !wt) {
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if (acl_add_perm(permset, ACL_READ|ACL_WRITE) < 0) {
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r = -errno;
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goto finish;
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}
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changed = true;
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}
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}
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if (!changed)
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goto finish;
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if (acl_calc_mask(&acl) < 0) {
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r = -errno;
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goto finish;
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}
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if (acl_set_file(path, ACL_TYPE_ACCESS, acl) < 0) {
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r = -errno;
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goto finish;
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}
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r = 0;
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finish:
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acl_free(acl);
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return r;
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}
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int devnode_acl_all(struct udev *udev,
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const char *seat,
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bool flush,
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bool del, uid_t old_uid,
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bool add, uid_t new_uid) {
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_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
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struct udev_list_entry *item = NULL, *first = NULL;
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_cleanup_set_free_free_ Set *nodes = NULL;
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_cleanup_closedir_ DIR *dir = NULL;
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struct dirent *dent;
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Iterator i;
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char *n;
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int r;
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assert(udev);
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nodes = set_new(&string_hash_ops);
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if (!nodes)
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return -ENOMEM;
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e = udev_enumerate_new(udev);
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if (!e)
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return -ENOMEM;
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if (isempty(seat))
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seat = "seat0";
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/* We can only match by one tag in libudev. We choose
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* "uaccess" for that. If we could match for two tags here we
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* could add the seat name as second match tag, but this would
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* be hardly optimizable in libudev, and hence checking the
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* second tag manually in our loop is a good solution. */
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r = udev_enumerate_add_match_tag(e, "uaccess");
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if (r < 0)
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return r;
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r = udev_enumerate_add_match_is_initialized(e);
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if (r < 0)
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return r;
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r = udev_enumerate_scan_devices(e);
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if (r < 0)
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return r;
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first = udev_enumerate_get_list_entry(e);
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udev_list_entry_foreach(item, first) {
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_cleanup_udev_device_unref_ struct udev_device *d = NULL;
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const char *node, *sn;
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d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
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if (!d)
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return -ENOMEM;
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sn = udev_device_get_property_value(d, "ID_SEAT");
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if (isempty(sn))
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sn = "seat0";
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if (!streq(seat, sn))
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continue;
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node = udev_device_get_devnode(d);
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/* In case people mistag devices with nodes, we need to ignore this */
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if (!node)
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continue;
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n = strdup(node);
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if (!n)
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return -ENOMEM;
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log_debug("Found udev node %s for seat %s", n, seat);
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r = set_consume(nodes, n);
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if (r < 0)
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return r;
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}
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/* udev exports "dead" device nodes to allow module on-demand loading,
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* these devices are not known to the kernel at this moment */
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dir = opendir("/run/udev/static_node-tags/uaccess");
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if (dir) {
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FOREACH_DIRENT(dent, dir, return -errno) {
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_cleanup_free_ char *unescaped_devname = NULL;
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unescaped_devname = cunescape(dent->d_name);
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if (!unescaped_devname)
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return -ENOMEM;
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n = strappend("/dev/", unescaped_devname);
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if (!n)
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return -ENOMEM;
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log_debug("Found static node %s for seat %s", n, seat);
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r = set_consume(nodes, n);
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if (r == -EEXIST)
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continue;
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if (r < 0)
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return r;
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}
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}
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r = 0;
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SET_FOREACH(n, nodes, i) {
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int k;
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log_debug("Changing ACLs at %s for seat %s (uid "UID_FMT"→"UID_FMT"%s%s)",
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n, seat, old_uid, new_uid,
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del ? " del" : "", add ? " add" : "");
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k = devnode_acl(n, flush, del, old_uid, add, new_uid);
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if (k == -ENOENT)
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log_debug("Device %s disappeared while setting ACLs", n);
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else if (k < 0 && r == 0)
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r = k;
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}
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return r;
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}
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