blob: 95dfc2f07782f9f6c700e71a0082c45776a8c333 [file] [log] [blame] [raw]
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <fcntl.h>
#include <unistd.h>
#include "sd-device.h"
#include "alloc-util.h"
#include "device-enumerator-private.h"
#include "device-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "set.h"
#include "sort-util.h"
#include "string-util.h"
#include "strv.h"
#define DEVICE_ENUMERATE_MAX_DEPTH 256
typedef enum DeviceEnumerationType {
DEVICE_ENUMERATION_TYPE_DEVICES,
DEVICE_ENUMERATION_TYPE_SUBSYSTEMS,
_DEVICE_ENUMERATION_TYPE_MAX,
_DEVICE_ENUMERATION_TYPE_INVALID = -1,
} DeviceEnumerationType;
struct sd_device_enumerator {
unsigned n_ref;
DeviceEnumerationType type;
sd_device **devices;
size_t n_devices, n_allocated, current_device_index;
bool scan_uptodate;
Set *match_subsystem;
Set *nomatch_subsystem;
Hashmap *match_sysattr;
Hashmap *nomatch_sysattr;
Hashmap *match_property;
Set *match_sysname;
Set *match_tag;
Set *match_parent;
bool match_allow_uninitialized;
};
_public_ int sd_device_enumerator_new(sd_device_enumerator **ret) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *enumerator = NULL;
assert(ret);
enumerator = new(sd_device_enumerator, 1);
if (!enumerator)
return -ENOMEM;
*enumerator = (sd_device_enumerator) {
.n_ref = 1,
.type = _DEVICE_ENUMERATION_TYPE_INVALID,
};
*ret = TAKE_PTR(enumerator);
return 0;
}
static sd_device_enumerator *device_enumerator_free(sd_device_enumerator *enumerator) {
size_t i;
assert(enumerator);
for (i = 0; i < enumerator->n_devices; i++)
sd_device_unref(enumerator->devices[i]);
free(enumerator->devices);
set_free(enumerator->match_subsystem);
set_free(enumerator->nomatch_subsystem);
hashmap_free(enumerator->match_sysattr);
hashmap_free(enumerator->nomatch_sysattr);
hashmap_free(enumerator->match_property);
set_free(enumerator->match_sysname);
set_free(enumerator->match_tag);
set_free(enumerator->match_parent);
return mfree(enumerator);
}
DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_enumerator, sd_device_enumerator, device_enumerator_free);
_public_ int sd_device_enumerator_add_match_subsystem(sd_device_enumerator *enumerator, const char *subsystem, int match) {
Set **set;
int r;
assert_return(enumerator, -EINVAL);
assert_return(subsystem, -EINVAL);
if (match)
set = &enumerator->match_subsystem;
else
set = &enumerator->nomatch_subsystem;
r = set_put_strdup(set, subsystem);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
_public_ int sd_device_enumerator_add_match_sysattr(sd_device_enumerator *enumerator, const char *sysattr, const char *value, int match) {
Hashmap **hashmap;
int r;
assert_return(enumerator, -EINVAL);
assert_return(sysattr, -EINVAL);
if (match)
hashmap = &enumerator->match_sysattr;
else
hashmap = &enumerator->nomatch_sysattr;
r = hashmap_put_strdup(hashmap, sysattr, value);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
_public_ int sd_device_enumerator_add_match_property(sd_device_enumerator *enumerator, const char *property, const char *value) {
int r;
assert_return(enumerator, -EINVAL);
assert_return(property, -EINVAL);
r = hashmap_put_strdup(&enumerator->match_property, property, value);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
_public_ int sd_device_enumerator_add_match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
int r;
assert_return(enumerator, -EINVAL);
assert_return(sysname, -EINVAL);
r = set_put_strdup(&enumerator->match_sysname, sysname);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
_public_ int sd_device_enumerator_add_match_tag(sd_device_enumerator *enumerator, const char *tag) {
int r;
assert_return(enumerator, -EINVAL);
assert_return(tag, -EINVAL);
r = set_put_strdup(&enumerator->match_tag, tag);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
int device_enumerator_add_match_parent_incremental(sd_device_enumerator *enumerator, sd_device *parent) {
const char *path;
int r;
assert(enumerator);
assert(parent);
r = sd_device_get_syspath(parent, &path);
if (r < 0)
return r;
r = set_put_strdup(&enumerator->match_parent, path);
if (r <= 0)
return r;
enumerator->scan_uptodate = false;
return 1;
}
_public_ int sd_device_enumerator_add_match_parent(sd_device_enumerator *enumerator, sd_device *parent) {
assert_return(enumerator, -EINVAL);
assert_return(parent, -EINVAL);
set_clear(enumerator->match_parent);
return device_enumerator_add_match_parent_incremental(enumerator, parent);
}
_public_ int sd_device_enumerator_allow_uninitialized(sd_device_enumerator *enumerator) {
assert_return(enumerator, -EINVAL);
enumerator->match_allow_uninitialized = true;
enumerator->scan_uptodate = false;
return 1;
}
int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator) {
assert_return(enumerator, -EINVAL);
enumerator->match_allow_uninitialized = false;
enumerator->scan_uptodate = false;
return 1;
}
static int device_compare(sd_device * const *_a, sd_device * const *_b) {
sd_device *a = *(sd_device **)_a, *b = *(sd_device **)_b;
const char *devpath_a, *devpath_b, *sound_a;
bool delay_a, delay_b;
int r;
assert_se(sd_device_get_devpath(a, &devpath_a) >= 0);
assert_se(sd_device_get_devpath(b, &devpath_b) >= 0);
sound_a = strstr(devpath_a, "/sound/card");
if (sound_a) {
/* For sound cards the control device must be enumerated last to
* make sure it's the final device node that gets ACLs applied.
* Applications rely on this fact and use ACL changes on the
* control node as an indicator that the ACL change of the
* entire sound card completed. The kernel makes this guarantee
* when creating those devices, and hence we should too when
* enumerating them. */
sound_a += STRLEN("/sound/card");
sound_a = strchr(sound_a, '/');
if (sound_a) {
unsigned prefix_len;
prefix_len = sound_a - devpath_a;
if (strncmp(devpath_a, devpath_b, prefix_len) == 0) {
const char *sound_b;
sound_b = devpath_b + prefix_len;
if (startswith(sound_a, "/controlC") &&
!startswith(sound_b, "/contolC"))
return 1;
if (!startswith(sound_a, "/controlC") &&
startswith(sound_b, "/controlC"))
return -1;
}
}
}
/* md and dm devices are enumerated after all other devices */
delay_a = strstr(devpath_a, "/block/md") || strstr(devpath_a, "/block/dm-");
delay_b = strstr(devpath_b, "/block/md") || strstr(devpath_b, "/block/dm-");
r = CMP(delay_a, delay_b);
if (r != 0)
return r;
return strcmp(devpath_a, devpath_b);
}
int device_enumerator_add_device(sd_device_enumerator *enumerator, sd_device *device) {
assert_return(enumerator, -EINVAL);
assert_return(device, -EINVAL);
if (!GREEDY_REALLOC(enumerator->devices, enumerator->n_allocated, enumerator->n_devices + 1))
return -ENOMEM;
enumerator->devices[enumerator->n_devices++] = sd_device_ref(device);
return 0;
}
static bool match_sysattr_value(sd_device *device, const char *sysattr, const char *match_value) {
const char *value;
int r;
assert(device);
assert(sysattr);
r = sd_device_get_sysattr_value(device, sysattr, &value);
if (r < 0)
return false;
if (!match_value)
return true;
if (fnmatch(match_value, value, 0) == 0)
return true;
return false;
}
static bool match_sysattr(sd_device_enumerator *enumerator, sd_device *device) {
const char *sysattr;
const char *value;
Iterator i;
assert(enumerator);
assert(device);
HASHMAP_FOREACH_KEY(value, sysattr, enumerator->nomatch_sysattr, i)
if (match_sysattr_value(device, sysattr, value))
return false;
HASHMAP_FOREACH_KEY(value, sysattr, enumerator->match_sysattr, i)
if (!match_sysattr_value(device, sysattr, value))
return false;
return true;
}
static bool match_property(sd_device_enumerator *enumerator, sd_device *device) {
const char *property;
const char *value;
Iterator i;
assert(enumerator);
assert(device);
if (hashmap_isempty(enumerator->match_property))
return true;
HASHMAP_FOREACH_KEY(value, property, enumerator->match_property, i) {
const char *property_dev, *value_dev;
FOREACH_DEVICE_PROPERTY(device, property_dev, value_dev) {
if (fnmatch(property, property_dev, 0) != 0)
continue;
if (!value && !value_dev)
return true;
if (!value || !value_dev)
continue;
if (fnmatch(value, value_dev, 0) == 0)
return true;
}
}
return false;
}
static bool match_tag(sd_device_enumerator *enumerator, sd_device *device) {
const char *tag;
Iterator i;
assert(enumerator);
assert(device);
SET_FOREACH(tag, enumerator->match_tag, i)
if (!sd_device_has_tag(device, tag))
return false;
return true;
}
static bool match_parent(sd_device_enumerator *enumerator, sd_device *device) {
const char *syspath_parent, *syspath;
Iterator i;
assert(enumerator);
assert(device);
if (set_isempty(enumerator->match_parent))
return true;
assert_se(sd_device_get_syspath(device, &syspath) >= 0);
SET_FOREACH(syspath_parent, enumerator->match_parent, i)
if (path_startswith(syspath, syspath_parent))
return true;
return false;
}
static bool match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
const char *sysname_match;
Iterator i;
assert(enumerator);
assert(sysname);
if (set_isempty(enumerator->match_sysname))
return true;
SET_FOREACH(sysname_match, enumerator->match_sysname, i)
if (fnmatch(sysname_match, sysname, 0) == 0)
return true;
return false;
}
static int enumerator_scan_dir_and_add_devices(sd_device_enumerator *enumerator, const char *basedir, const char *subdir1, const char *subdir2) {
_cleanup_closedir_ DIR *dir = NULL;
char *path;
struct dirent *dent;
int r = 0;
assert(enumerator);
assert(basedir);
path = strjoina("/sys/", basedir, "/");
if (subdir1)
path = strjoina(path, subdir1, "/");
if (subdir2)
path = strjoina(path, subdir2, "/");
dir = opendir(path);
if (!dir)
return -errno;
FOREACH_DIRENT_ALL(dent, dir, return -errno) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
char syspath[strlen(path) + 1 + strlen(dent->d_name) + 1];
int initialized, k;
if (dent->d_name[0] == '.')
continue;
if (!match_sysname(enumerator, dent->d_name))
continue;
(void) sprintf(syspath, "%s%s", path, dent->d_name);
k = sd_device_new_from_syspath(&device, syspath);
if (k < 0) {
if (k != -ENODEV)
/* this is necessarily racey, so ignore missing devices */
r = k;
continue;
}
initialized = sd_device_get_is_initialized(device);
if (initialized < 0) {
if (initialized != -ENOENT)
/* this is necessarily racey, so ignore missing devices */
r = initialized;
continue;
}
/*
* All devices with a device node or network interfaces
* possibly need udev to adjust the device node permission
* or context, or rename the interface before it can be
* reliably used from other processes.
*
* For now, we can only check these types of devices, we
* might not store a database, and have no way to find out
* for all other types of devices.
*/
if (!enumerator->match_allow_uninitialized &&
!initialized &&
(sd_device_get_devnum(device, NULL) >= 0 ||
sd_device_get_ifindex(device, NULL) >= 0))
continue;
if (!match_parent(enumerator, device))
continue;
if (!match_tag(enumerator, device))
continue;
if (!match_property(enumerator, device))
continue;
if (!match_sysattr(enumerator, device))
continue;
k = device_enumerator_add_device(enumerator, device);
if (k < 0)
r = k;
}
return r;
}
static bool match_subsystem(sd_device_enumerator *enumerator, const char *subsystem) {
const char *subsystem_match;
Iterator i;
assert(enumerator);
if (!subsystem)
return false;
SET_FOREACH(subsystem_match, enumerator->nomatch_subsystem, i)
if (fnmatch(subsystem_match, subsystem, 0) == 0)
return false;
if (set_isempty(enumerator->match_subsystem))
return true;
SET_FOREACH(subsystem_match, enumerator->match_subsystem, i)
if (fnmatch(subsystem_match, subsystem, 0) == 0)
return true;
return false;
}
static int enumerator_scan_dir(sd_device_enumerator *enumerator, const char *basedir, const char *subdir, const char *subsystem) {
_cleanup_closedir_ DIR *dir = NULL;
char *path;
struct dirent *dent;
int r = 0;
path = strjoina("/sys/", basedir);
dir = opendir(path);
if (!dir)
return -errno;
log_debug("sd-device-enumerator: Scanning %s", path);
FOREACH_DIRENT_ALL(dent, dir, return -errno) {
int k;
if (dent->d_name[0] == '.')
continue;
if (!match_subsystem(enumerator, subsystem ? : dent->d_name))
continue;
k = enumerator_scan_dir_and_add_devices(enumerator, basedir, dent->d_name, subdir);
if (k < 0)
r = k;
}
return r;
}
static int enumerator_scan_devices_tag(sd_device_enumerator *enumerator, const char *tag) {
_cleanup_closedir_ DIR *dir = NULL;
char *path;
struct dirent *dent;
int r = 0;
assert(enumerator);
assert(tag);
path = strjoina("/run/udev/tags/", tag);
dir = opendir(path);
if (!dir) {
if (errno != ENOENT)
return log_debug_errno(errno, "sd-device-enumerator: Failed to open tags directory %s: %m", path);
return 0;
}
/* TODO: filter away subsystems? */
FOREACH_DIRENT_ALL(dent, dir, return -errno) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
const char *subsystem, *sysname;
int k;
if (dent->d_name[0] == '.')
continue;
k = sd_device_new_from_device_id(&device, dent->d_name);
if (k < 0) {
if (k != -ENODEV)
/* this is necessarily racy, so ignore missing devices */
r = k;
continue;
}
k = sd_device_get_subsystem(device, &subsystem);
if (k < 0) {
if (k != -ENOENT)
/* this is necessarily racy, so ignore missing devices */
r = k;
continue;
}
if (!match_subsystem(enumerator, subsystem))
continue;
k = sd_device_get_sysname(device, &sysname);
if (k < 0) {
r = k;
continue;
}
if (!match_sysname(enumerator, sysname))
continue;
if (!match_parent(enumerator, device))
continue;
if (!match_property(enumerator, device))
continue;
if (!match_sysattr(enumerator, device))
continue;
k = device_enumerator_add_device(enumerator, device);
if (k < 0) {
r = k;
continue;
}
}
return r;
}
static int enumerator_scan_devices_tags(sd_device_enumerator *enumerator) {
const char *tag;
Iterator i;
int r = 0;
assert(enumerator);
SET_FOREACH(tag, enumerator->match_tag, i) {
int k;
k = enumerator_scan_devices_tag(enumerator, tag);
if (k < 0)
r = k;
}
return r;
}
static int parent_add_child(sd_device_enumerator *enumerator, const char *path) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
const char *subsystem, *sysname;
int r;
r = sd_device_new_from_syspath(&device, path);
if (r == -ENODEV)
/* this is necessarily racy, so ignore missing devices */
return 0;
else if (r < 0)
return r;
r = sd_device_get_subsystem(device, &subsystem);
if (r == -ENOENT)
return 0;
if (r < 0)
return r;
if (!match_subsystem(enumerator, subsystem))
return 0;
r = sd_device_get_sysname(device, &sysname);
if (r < 0)
return r;
if (!match_sysname(enumerator, sysname))
return 0;
if (!match_property(enumerator, device))
return 0;
if (!match_sysattr(enumerator, device))
return 0;
r = device_enumerator_add_device(enumerator, device);
if (r < 0)
return r;
return 1;
}
static int parent_crawl_children(sd_device_enumerator *enumerator, const char *path, unsigned maxdepth) {
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *dent;
int r = 0;
dir = opendir(path);
if (!dir)
return log_debug_errno(errno, "sd-device-enumerator: Failed to open parent directory %s: %m", path);
FOREACH_DIRENT_ALL(dent, dir, return -errno) {
_cleanup_free_ char *child = NULL;
int k;
if (dent->d_name[0] == '.')
continue;
if (dent->d_type != DT_DIR)
continue;
child = path_join(path, dent->d_name);
if (!child)
return -ENOMEM;
k = parent_add_child(enumerator, child);
if (k < 0)
r = k;
if (maxdepth > 0)
parent_crawl_children(enumerator, child, maxdepth - 1);
else
log_debug("sd-device-enumerator: Max depth reached, %s: ignoring devices", child);
}
return r;
}
static int enumerator_scan_devices_children(sd_device_enumerator *enumerator) {
const char *path;
int r = 0, k;
Iterator i;
SET_FOREACH(path, enumerator->match_parent, i) {
k = parent_add_child(enumerator, path);
if (k < 0)
r = k;
k = parent_crawl_children(enumerator, path, DEVICE_ENUMERATE_MAX_DEPTH);
if (k < 0)
r = k;
}
return r;
}
static int enumerator_scan_devices_all(sd_device_enumerator *enumerator) {
int r = 0;
log_debug("sd-device-enumerator: Scan all dirs");
if (access("/sys/subsystem", F_OK) >= 0) {
/* we have /subsystem/, forget all the old stuff */
r = enumerator_scan_dir(enumerator, "subsystem", "devices", NULL);
if (r < 0)
return log_debug_errno(r, "sd-device-enumerator: Failed to scan /sys/subsystem: %m");
} else {
int k;
k = enumerator_scan_dir(enumerator, "bus", "devices", NULL);
if (k < 0) {
log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/bus: %m");
r = k;
}
k = enumerator_scan_dir(enumerator, "class", NULL, NULL);
if (k < 0) {
log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/class: %m");
r = k;
}
}
return r;
}
static void device_enumerator_dedup_devices(sd_device_enumerator *enumerator) {
sd_device **a, **b, **end;
assert(enumerator);
if (enumerator->n_devices <= 1)
return;
a = enumerator->devices + 1;
b = enumerator->devices;
end = enumerator->devices + enumerator->n_devices;
for (; a < end; a++) {
const char *devpath_a, *devpath_b;
assert_se(sd_device_get_devpath(*a, &devpath_a) >= 0);
assert_se(sd_device_get_devpath(*b, &devpath_b) >= 0);
if (path_equal(devpath_a, devpath_b))
sd_device_unref(*a);
else
*(++b) = *a;
}
enumerator->n_devices = b - enumerator->devices + 1;
}
int device_enumerator_scan_devices(sd_device_enumerator *enumerator) {
int r = 0, k;
size_t i;
assert(enumerator);
if (enumerator->scan_uptodate &&
enumerator->type == DEVICE_ENUMERATION_TYPE_DEVICES)
return 0;
for (i = 0; i < enumerator->n_devices; i++)
sd_device_unref(enumerator->devices[i]);
enumerator->n_devices = 0;
if (!set_isempty(enumerator->match_tag)) {
k = enumerator_scan_devices_tags(enumerator);
if (k < 0)
r = k;
} else if (enumerator->match_parent) {
k = enumerator_scan_devices_children(enumerator);
if (k < 0)
r = k;
} else {
k = enumerator_scan_devices_all(enumerator);
if (k < 0)
r = k;
}
typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
device_enumerator_dedup_devices(enumerator);
enumerator->scan_uptodate = true;
enumerator->type = DEVICE_ENUMERATION_TYPE_DEVICES;
return r;
}
_public_ sd_device *sd_device_enumerator_get_device_first(sd_device_enumerator *enumerator) {
int r;
assert_return(enumerator, NULL);
r = device_enumerator_scan_devices(enumerator);
if (r < 0)
return NULL;
enumerator->current_device_index = 0;
if (enumerator->n_devices == 0)
return NULL;
return enumerator->devices[0];
}
_public_ sd_device *sd_device_enumerator_get_device_next(sd_device_enumerator *enumerator) {
assert_return(enumerator, NULL);
if (!enumerator->scan_uptodate ||
enumerator->type != DEVICE_ENUMERATION_TYPE_DEVICES ||
enumerator->current_device_index + 1 >= enumerator->n_devices)
return NULL;
return enumerator->devices[++enumerator->current_device_index];
}
int device_enumerator_scan_subsystems(sd_device_enumerator *enumerator) {
const char *subsysdir;
int r = 0, k;
size_t i;
assert(enumerator);
if (enumerator->scan_uptodate &&
enumerator->type == DEVICE_ENUMERATION_TYPE_SUBSYSTEMS)
return 0;
for (i = 0; i < enumerator->n_devices; i++)
sd_device_unref(enumerator->devices[i]);
enumerator->n_devices = 0;
/* modules */
if (match_subsystem(enumerator, "module")) {
k = enumerator_scan_dir_and_add_devices(enumerator, "module", NULL, NULL);
if (k < 0) {
log_debug_errno(k, "sd-device-enumerator: Failed to scan modules: %m");
r = k;
}
}
if (access("/sys/subsystem", F_OK) >= 0)
subsysdir = "subsystem";
else
subsysdir = "bus";
/* subsystems (only buses support coldplug) */
if (match_subsystem(enumerator, "subsystem")) {
k = enumerator_scan_dir_and_add_devices(enumerator, subsysdir, NULL, NULL);
if (k < 0) {
log_debug_errno(k, "sd-device-enumerator: Failed to scan subsystems: %m");
r = k;
}
}
/* subsystem drivers */
if (match_subsystem(enumerator, "drivers")) {
k = enumerator_scan_dir(enumerator, subsysdir, "drivers", "drivers");
if (k < 0) {
log_debug_errno(k, "sd-device-enumerator: Failed to scan drivers: %m");
r = k;
}
}
typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
device_enumerator_dedup_devices(enumerator);
enumerator->scan_uptodate = true;
enumerator->type = DEVICE_ENUMERATION_TYPE_SUBSYSTEMS;
return r;
}
_public_ sd_device *sd_device_enumerator_get_subsystem_first(sd_device_enumerator *enumerator) {
int r;
assert_return(enumerator, NULL);
r = device_enumerator_scan_subsystems(enumerator);
if (r < 0)
return NULL;
enumerator->current_device_index = 0;
if (enumerator->n_devices == 0)
return NULL;
return enumerator->devices[0];
}
_public_ sd_device *sd_device_enumerator_get_subsystem_next(sd_device_enumerator *enumerator) {
assert_return(enumerator, NULL);
if (!enumerator->scan_uptodate ||
enumerator->type != DEVICE_ENUMERATION_TYPE_SUBSYSTEMS ||
enumerator->current_device_index + 1 >= enumerator->n_devices)
return NULL;
return enumerator->devices[++enumerator->current_device_index];
}
sd_device *device_enumerator_get_first(sd_device_enumerator *enumerator) {
assert_return(enumerator, NULL);
if (!enumerator->scan_uptodate)
return NULL;
enumerator->current_device_index = 0;
if (enumerator->n_devices == 0)
return NULL;
return enumerator->devices[0];
}
sd_device *device_enumerator_get_next(sd_device_enumerator *enumerator) {
assert_return(enumerator, NULL);
if (!enumerator->scan_uptodate ||
enumerator->current_device_index + 1 >= enumerator->n_devices)
return NULL;
return enumerator->devices[++enumerator->current_device_index];
}
sd_device **device_enumerator_get_devices(sd_device_enumerator *enumerator, size_t *ret_n_devices) {
assert(enumerator);
assert(ret_n_devices);
if (!enumerator->scan_uptodate)
return NULL;
*ret_n_devices = enumerator->n_devices;
return enumerator->devices;
}