sd-device.c revision 24eb4a30982ed18d4716bd59c454a72f161d5982
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier/***
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier This file is part of systemd.
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier Copyright 2014 Tom Gundersen <teg@jklm.no>
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier systemd is free software; you can redistribute it and/or modify it
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier under the terms of the GNU Lesser General Public License as published by
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier the Free Software Foundation; either version 2.1 of the License, or
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier (at your option) any later version.
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier systemd is distributed in the hope that it will be useful, but
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier WITHOUT ANY WARRANTY; without even the implied warranty of
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier Lesser General Public License for more details.
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier You should have received a copy of the GNU Lesser General Public License
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier along with systemd; If not, see <http://www.gnu.org/licenses/>.
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier***/
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include <ctype.h>
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include <sys/types.h>
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include <net/if.h>
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "util.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "macro.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "path-util.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "strxcpyx.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "fileio.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "hashmap.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "set.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "strv.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "sd-device.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "device-util.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "device-private.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier#include "device-internal.h"
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalierint device_new_aux(sd_device **ret) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier _cleanup_device_unref_ sd_device *device = NULL;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier assert(ret);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier device = new0(sd_device, 1);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (!device)
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier return -ENOMEM;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier device->n_ref = 1;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier device->watch_handle = -1;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier *ret = device;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier device = NULL;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier return 0;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier}
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier_public_ sd_device *sd_device_ref(sd_device *device) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (device)
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier assert_se(++ device->n_ref >= 2);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier return device;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier}
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier_public_ sd_device *sd_device_unref(sd_device *device) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (device && -- device->n_ref == 0) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier sd_device_unref(device->parent);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->syspath);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->sysname);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->devtype);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->devname);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->subsystem);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->driver);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->id_filename);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->properties_strv);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device->properties_nulstr);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier ordered_hashmap_free_free_free(device->properties);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier ordered_hashmap_free_free_free(device->properties_db);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier hashmap_free_free_free(device->sysattr_values);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier set_free_free(device->sysattrs);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier set_free_free(device->tags);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier set_free_free(device->devlinks);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier free(device);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier }
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier return NULL;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier}
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalierint device_add_property_aux(sd_device *device, const char *_key, const char *_value, bool db) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier OrderedHashmap **properties;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier assert(device);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier assert(_key);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (db)
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier properties = &device->properties_db;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier else
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier properties = &device->properties;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (_value) {
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier _cleanup_free_ char *key = NULL, *value = NULL, *old_key = NULL, *old_value = NULL;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier int r;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier r = ordered_hashmap_ensure_allocated(properties, &string_hash_ops);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (r < 0)
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier return r;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier key = strdup(_key);
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier if (!key)
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier return -ENOMEM;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier value = strdup(_value);
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier if (!value)
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier return -ENOMEM;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier old_value = ordered_hashmap_get2(*properties, key, (void**) &old_key);
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier r = ordered_hashmap_replace(*properties, key, value);
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier if (r < 0)
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier return r;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier key = NULL;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier value = NULL;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier } else {
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier _cleanup_free_ char *key = NULL;
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier _cleanup_free_ char *value = NULL;
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier value = ordered_hashmap_remove2(*properties, _key, (void**) &key);
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier }
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier if (!db) {
2de61bbebfe6a1a97709b3277b150cacc30a79cdRonny Chevalier device->properties_generation ++;
4630bbb766d564eafee3bfcd36342fbae8534c15Ronny Chevalier device->properties_buf_outdated = true;
4630bbb766d564eafee3bfcd36342fbae8534c15Ronny Chevalier }
106ecd769d57116ad81efdea2c27557fba062138Ronny Chevalier
return 0;
}
int device_add_property_internal(sd_device *device, const char *key, const char *value) {
return device_add_property_aux(device, key, value, false);
}
int device_set_syspath(sd_device *device, const char *_syspath, bool verify) {
_cleanup_free_ char *syspath = NULL;
const char *devpath;
int r;
assert(device);
assert(_syspath);
/* must be a subdirectory of /sys */
if (!path_startswith(_syspath, "/sys/")) {
log_debug("sd-device: syspath '%s' is not a subdirectory of /sys", _syspath);
return -EINVAL;
}
if (verify) {
r = readlink_and_canonicalize(_syspath, &syspath);
if (r == -EINVAL) {
/* not a symlink */
syspath = canonicalize_file_name(_syspath);
if (!syspath) {
log_debug("sd-device: could not canonicalize '%s': %m", _syspath);
return -errno;
}
/* ignore errors due to the link not being a symlink */
} else if (r < 0 && r != -EINVAL) {
log_debug("sd-device: could not get target of '%s': %s", _syspath, strerror(-r));
return r;
}
if (path_startswith(syspath, "/sys/devices/")) {
char *path;
/* all 'devices' require an 'uevent' file */
path = strjoina(syspath, "/uevent");
r = access(path, F_OK);
if (r < 0) {
log_debug("sd-device: %s does not have an uevent file: %m", syspath);
return -errno;
}
} else {
/* everything else just just needs to be a directory */
if (!is_dir(syspath, false)) {
log_debug("sd-device: %s is not a directory", syspath);
return -EINVAL;
}
}
} else {
syspath = strdup(_syspath);
if (!syspath)
return -ENOMEM;
}
devpath = syspath + strlen("/sys");
r = device_add_property_internal(device, "DEVPATH", devpath);
if (r < 0)
return r;
free(device->syspath);
device->syspath = syspath;
syspath = NULL;
device->devpath = devpath;
return 0;
}
_public_ int sd_device_new_from_syspath(sd_device **ret, const char *syspath) {
_cleanup_device_unref_ sd_device *device = NULL;
int r;
assert_return(ret, -EINVAL);
assert_return(syspath, -EINVAL);
r = device_new_aux(&device);
if (r < 0)
return r;
r = device_set_syspath(device, syspath, true);
if (r < 0)
return r;
*ret = device;
device = NULL;
return 0;
}
_public_ int sd_device_new_from_devnum(sd_device **ret, char type, dev_t devnum) {
char *syspath;
char id[DECIMAL_STR_MAX(unsigned) * 2 + 1];
assert_return(ret, -EINVAL);
assert_return(type == 'b' || type == 'c', -EINVAL);
/* use /sys/dev/{block,char}/<maj>:<min> link */
snprintf(id, sizeof(id), "%u:%u", major(devnum), minor(devnum));
syspath = strjoina("/sys/dev/", (type == 'b' ? "block" : "char"), "/", id);
return sd_device_new_from_syspath(ret, syspath);
}
_public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *subsystem, const char *sysname) {
char *syspath;
assert_return(ret, -EINVAL);
assert_return(subsystem, -EINVAL);
assert_return(sysname, -EINVAL);
if (streq(subsystem, "subsystem")) {
syspath = strjoina("/sys/subsystem/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
syspath = strjoina("/sys/bus/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
syspath = strjoina("/sys/class/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
} else if (streq(subsystem, "module")) {
syspath = strjoina("/sys/module/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
} else if (streq(subsystem, "drivers")) {
char subsys[PATH_MAX];
char *driver;
strscpy(subsys, sizeof(subsys), sysname);
driver = strchr(subsys, ':');
if (driver) {
driver[0] = '\0';
driver++;
syspath = strjoina("/sys/subsystem/", subsys, "/drivers/", driver);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
syspath = strjoina("/sys/bus/", subsys, "/drivers/", driver);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
} else
return -EINVAL;
} else {
syspath = strjoina("/sys/subsystem/", subsystem, "/devices/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
syspath = strjoina("/sys/bus/", subsystem, "/devices/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
syspath = strjoina("/sys/class/", subsystem, "/", sysname);
if (access(syspath, F_OK) >= 0)
return sd_device_new_from_syspath(ret, syspath);
}
return -ENOENT;
}
int device_set_devtype(sd_device *device, const char *_devtype) {
_cleanup_free_ char *devtype = NULL;
int r;
assert(device);
assert(_devtype);
devtype = strdup(_devtype);
if (!devtype)
return -ENOMEM;
r = device_add_property_internal(device, "DEVTYPE", devtype);
if (r < 0)
return r;
free(device->devtype);
device->devtype = devtype;
devtype = NULL;
return 0;
}
int device_set_ifindex(sd_device *device, const char *_ifindex) {
int ifindex, r;
assert(device);
assert(_ifindex);
r = safe_atoi(_ifindex, &ifindex);
if (r < 0)
return r;
if (ifindex <= 0)
return -EINVAL;
r = device_add_property_internal(device, "IFINDEX", _ifindex);
if (r < 0)
return r;
device->ifindex = ifindex;
return 0;
}
int device_set_devname(sd_device *device, const char *_devname) {
_cleanup_free_ char *devname = NULL;
int r;
assert(device);
assert(_devname);
if (_devname[0] != '/') {
r = asprintf(&devname, "/dev/%s", _devname);
if (r < 0)
return -ENOMEM;
} else {
devname = strdup(_devname);
if (!devname)
return -ENOMEM;
}
r = device_add_property_internal(device, "DEVNAME", devname);
if (r < 0)
return r;
free(device->devname);
device->devname = devname;
devname = NULL;
return 0;
}
int device_set_devmode(sd_device *device, const char *_devmode) {
unsigned devmode;
int r;
assert(device);
assert(_devmode);
r = safe_atou(_devmode, &devmode);
if (r < 0)
return r;
if (devmode > 07777)
return -EINVAL;
r = device_add_property_internal(device, "DEVMODE", _devmode);
if (r < 0)
return r;
device->devmode = devmode;
return 0;
}
int device_set_devnum(sd_device *device, const char *major, const char *minor) {
unsigned maj = 0, min = 0;
int r;
assert(device);
assert(major);
r = safe_atou(major, &maj);
if (r < 0)
return r;
if (!maj)
return 0;
if (minor) {
r = safe_atou(minor, &min);
if (r < 0)
return r;
}
r = device_add_property_internal(device, "MAJOR", major);
if (r < 0)
return r;
if (minor) {
r = device_add_property_internal(device, "MINOR", minor);
if (r < 0)
return r;
}
device->devnum = makedev(maj, min);
return 0;
}
static int handle_uevent_line(sd_device *device, const char *key, const char *value, const char **major, const char **minor) {
int r;
assert(device);
assert(key);
assert(value);
assert(major);
assert(minor);
if (streq(key, "DEVTYPE")) {
r = device_set_devtype(device, value);
if (r < 0)
return r;
} else if (streq(key, "IFINDEX")) {
r = device_set_ifindex(device, value);
if (r < 0)
return r;
} else if (streq(key, "DEVNAME")) {
r = device_set_devname(device, value);
if (r < 0)
return r;
} else if (streq(key, "DEVMODE")) {
r = device_set_devmode(device, value);
if (r < 0)
return r;
} else if (streq(key, "MAJOR"))
*major = value;
else if (streq(key, "MINOR"))
*minor = value;
else {
r = device_add_property_internal(device, key, value);
if (r < 0)
return r;
}
return 0;
}
int device_read_uevent_file(sd_device *device) {
_cleanup_free_ char *uevent = NULL;
const char *syspath, *key, *value, *major = NULL, *minor = NULL;
char *path;
size_t uevent_len;
unsigned i;
int r;
enum {
PRE_KEY,
KEY,
PRE_VALUE,
VALUE,
INVALID_LINE,
} state = PRE_KEY;
assert(device);
if (device->uevent_loaded || device->sealed)
return 0;
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
path = strjoina(syspath, "/uevent");
r = read_full_file(path, &uevent, &uevent_len);
if (r < 0) {
log_debug("sd-device: failed to read uevent file '%s': %s", path, strerror(-r));
return r;
}
for (i = 0; i < uevent_len; i++) {
switch (state) {
case PRE_KEY:
if (!strchr(NEWLINE, uevent[i])) {
key = &uevent[i];
state = KEY;
}
break;
case KEY:
if (uevent[i] == '=') {
uevent[i] = '\0';
state = PRE_VALUE;
} else if (strchr(NEWLINE, uevent[i])) {
uevent[i] = '\0';
log_debug("sd-device: ignoring invalid uevent line '%s'", key);
state = PRE_KEY;
}
break;
case PRE_VALUE:
value = &uevent[i];
state = VALUE;
break;
case VALUE:
if (strchr(NEWLINE, uevent[i])) {
uevent[i] = '\0';
r = handle_uevent_line(device, key, value, &major, &minor);
if (r < 0)
log_debug("sd-device: failed to handle uevent entry '%s=%s': %s", key, value, strerror(-r));
state = PRE_KEY;
}
break;
default:
assert_not_reached("invalid state when parsing uevent file");
}
}
if (major) {
r = device_set_devnum(device, major, minor);
if (r < 0)
log_debug("sd-device: could not set 'MAJOR=%s' or 'MINOR=%s' from '%s': %s", major, minor, path, strerror(-r));
}
device->uevent_loaded = true;
return 0;
}
_public_ int sd_device_get_ifindex(sd_device *device, int *ifindex) {
int r;
assert_return(device, -EINVAL);
assert_return(ifindex, -EINVAL);
r = device_read_uevent_file(device);
if (r < 0)
return r;
*ifindex = device->ifindex;
return 0;
}
_public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
int r;
assert_return(ret, -EINVAL);
assert_return(id, -EINVAL);
switch (id[0]) {
case 'b':
case 'c':
{
char type;
int maj, min;
r = sscanf(id, "%c%i:%i", &type, &maj, &min);
if (r != 3)
return -EINVAL;
return sd_device_new_from_devnum(ret, type, makedev(maj, min));
}
case 'n':
{
_cleanup_device_unref_ sd_device *device = NULL;
_cleanup_close_ int sk = -1;
struct ifreq ifr = {};
int ifindex;
r = safe_atoi(&id[1], &ifr.ifr_ifindex);
if (r < 0)
return r;
else if (ifr.ifr_ifindex <= 0)
return -EINVAL;
sk = socket(PF_INET, SOCK_DGRAM, 0);
if (sk < 0)
return -errno;
r = ioctl(sk, SIOCGIFNAME, &ifr);
if (r < 0)
return -errno;
r = sd_device_new_from_subsystem_sysname(&device, "net", ifr.ifr_name);
if (r < 0)
return r;
r = sd_device_get_ifindex(device, &ifindex);
if (r < 0)
return r;
/* this si racey, so we might end up with the wrong device */
if (ifr.ifr_ifindex != ifindex)
return -ENODEV;
*ret = device;
device = NULL;
return 0;
}
case '+':
{
char subsys[PATH_MAX];
char *sysname;
(void)strscpy(subsys, sizeof(subsys), id + 1);
sysname = strchr(subsys, ':');
if (!sysname)
return -EINVAL;
sysname[0] = '\0';
sysname ++;
return sd_device_new_from_subsystem_sysname(ret, subsys, sysname);
}
default:
return -EINVAL;
}
}
_public_ int sd_device_get_syspath(sd_device *device, const char **ret) {
assert_return(device, -EINVAL);
assert_return(ret, -EINVAL);
assert(path_startswith(device->syspath, "/sys/"));
*ret = device->syspath;
return 0;
}
static int device_new_from_child(sd_device **ret, sd_device *child) {
_cleanup_free_ char *path = NULL;
const char *subdir, *syspath;
int r;
assert(ret);
assert(child);
r = sd_device_get_syspath(child, &syspath);
if (r < 0)
return r;
path = strdup(syspath);
if (!path)
return -ENOMEM;
subdir = path + strlen("/sys");
for (;;) {
char *pos;
pos = strrchr(subdir, '/');
if (!pos || pos < subdir + 2)
break;
*pos = '\0';
r = sd_device_new_from_syspath(ret, path);
if (r < 0)
continue;
return 0;
}
return -ENOENT;
}
_public_ int sd_device_get_parent(sd_device *child, sd_device **ret) {
assert_return(ret, -EINVAL);
assert_return(child, -EINVAL);
if (!child->parent_set) {
child->parent_set = true;
(void)device_new_from_child(&child->parent, child);
}
if (!child->parent)
return -ENOENT;
*ret = child->parent;
return 0;
}
int device_set_subsystem(sd_device *device, const char *_subsystem) {
_cleanup_free_ char *subsystem = NULL;
int r;
assert(device);
assert(_subsystem);
subsystem = strdup(_subsystem);
if (!subsystem)
return -ENOMEM;
r = device_add_property_internal(device, "SUBSYSTEM", subsystem);
if (r < 0)
return r;
free(device->subsystem);
device->subsystem = subsystem;
subsystem = NULL;
device->subsystem_set = true;
return 0;
}
_public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
assert_return(ret, -EINVAL);
assert_return(device, -EINVAL);
if (!device->subsystem_set) {
_cleanup_free_ char *subsystem = NULL;
const char *syspath;
char *path;
int r;
/* read 'subsystem' link */
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
path = strjoina(syspath, "/subsystem");
r = readlink_value(path, &subsystem);
if (r >= 0)
r = device_set_subsystem(device, subsystem);
/* use implicit names */
else if (path_startswith(device->devpath, "/module/"))
r = device_set_subsystem(device, "module");
else if (strstr(device->devpath, "/drivers/"))
r = device_set_subsystem(device, "drivers");
else if (path_startswith(device->devpath, "/subsystem/") ||
path_startswith(device->devpath, "/class/") ||
path_startswith(device->devpath, "/buss/"))
r = device_set_subsystem(device, "subsystem");
if (r < 0)
return r;
device->subsystem_set = true;
}
*ret = device->subsystem;
return 0;
}
_public_ int sd_device_get_devtype(sd_device *device, const char **devtype) {
int r;
assert(devtype);
assert(device);
r = device_read_uevent_file(device);
if (r < 0)
return r;
*devtype = device->devtype;
return 0;
}
_public_ int sd_device_get_parent_with_subsystem_devtype(sd_device *child, const char *subsystem, const char *devtype, sd_device **ret) {
sd_device *parent = NULL;
int r;
assert_return(child, -EINVAL);
assert_return(subsystem, -EINVAL);
r = sd_device_get_parent(child, &parent);
while (r >= 0) {
const char *parent_subsystem = NULL;
const char *parent_devtype = NULL;
(void)sd_device_get_subsystem(parent, &parent_subsystem);
if (streq_ptr(parent_subsystem, subsystem)) {
if (!devtype)
break;
(void)sd_device_get_devtype(parent, &parent_devtype);
if (streq_ptr(parent_devtype, devtype))
break;
}
r = sd_device_get_parent(parent, &parent);
}
if (r < 0)
return r;
*ret = parent;
return 0;
}
_public_ int sd_device_get_devnum(sd_device *device, dev_t *devnum) {
int r;
assert_return(device, -EINVAL);
assert_return(devnum, -EINVAL);
r = device_read_uevent_file(device);
if (r < 0)
return r;
*devnum = device->devnum;
return 0;
}
int device_set_driver(sd_device *device, const char *_driver) {
_cleanup_free_ char *driver = NULL;
int r;
assert(device);
assert(_driver);
driver = strdup(_driver);
if (!driver)
return -ENOMEM;
r = device_add_property_internal(device, "DRIVER", driver);
if (r < 0)
return r;
free(device->driver);
device->driver = driver;
driver = NULL;
device->driver_set = true;
return 0;
}
_public_ int sd_device_get_driver(sd_device *device, const char **ret) {
assert_return(device, -EINVAL);
assert_return(ret, -EINVAL);
if (!device->driver_set) {
_cleanup_free_ char *driver = NULL;
const char *syspath;
char *path;
int r;
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
path = strjoina(syspath, "/driver");
r = readlink_value(path, &driver);
if (r >= 0) {
r = device_set_driver(device, driver);
if (r < 0)
return r;
}
}
*ret = device->driver;
return 0;
}
_public_ int sd_device_get_devpath(sd_device *device, const char **devpath) {
assert_return(device, -EINVAL);
assert_return(devpath, -EINVAL);
assert(device->devpath);
assert(device->devpath[0] == '/');
*devpath = device->devpath;
return 0;
}
_public_ int sd_device_get_devname(sd_device *device, const char **devname) {
int r;
assert_return(device, -EINVAL);
assert_return(devname, -EINVAL);
r = device_read_uevent_file(device);
if (r < 0)
return r;
if (!device->devname)
return -ENOENT;
assert(path_startswith(device->devname, "/dev/"));
*devname = device->devname;
return 0;
}
static int device_set_sysname(sd_device *device) {
_cleanup_free_ char *sysname = NULL;
const char *sysnum = NULL;
const char *pos;
size_t len = 0;
pos = strrchr(device->devpath, '/');
if (!pos)
return -EINVAL;
pos ++;
/* devpath is not a root directory */
if (*pos == '\0' || pos <= device->devpath)
return -EINVAL;
sysname = strdup(pos);
if (!sysname)
return -ENOMEM;
/* some devices have '!' in their name, change that to '/' */
while (sysname[len] != '\0') {
if (sysname[len] == '!')
sysname[len] = '/';
len ++;
}
/* trailing number */
while (len > 0 && isdigit(sysname[--len]))
sysnum = &sysname[len];
if (len == 0)
sysnum = NULL;
free(device->sysname);
device->sysname = sysname;
sysname = NULL;
device->sysnum = sysnum;
device->sysname_set = true;
return 0;
}
_public_ int sd_device_get_sysname(sd_device *device, const char **ret) {
int r;
assert_return(device, -EINVAL);
assert_return(ret, -EINVAL);
if (!device->sysname_set) {
r = device_set_sysname(device);
if (r < 0)
return r;
}
*ret = device->sysname;
return 0;
}
_public_ int sd_device_get_sysnum(sd_device *device, const char **ret) {
int r;
assert_return(device, -EINVAL);
assert_return(ret, -EINVAL);
if (!device->sysname_set) {
r = device_set_sysname(device);
if (r < 0)
return r;
}
*ret = device->sysnum;
return 0;
}
static bool is_valid_tag(const char *tag) {
assert(tag);
return !strchr(tag, ':') && !strchr(tag, ' ');
}
int device_add_tag(sd_device *device, const char *tag) {
int r;
assert(device);
assert(tag);
if (!is_valid_tag(tag))
return -EINVAL;
r = set_ensure_allocated(&device->tags, &string_hash_ops);
if (r < 0)
return r;
r = set_put_strdup(device->tags, tag);
if (r < 0)
return r;
device->tags_generation ++;
device->property_tags_outdated = true;
return 0;
}
int device_add_devlink(sd_device *device, const char *devlink) {
int r;
assert(device);
assert(devlink);
r = set_ensure_allocated(&device->devlinks, &string_hash_ops);
if (r < 0)
return r;
r = set_put_strdup(device->devlinks, devlink);
if (r < 0)
return r;
device->devlinks_generation ++;
device->property_devlinks_outdated = true;
return 0;
}
static int device_add_property_internal_from_string(sd_device *device, const char *str) {
_cleanup_free_ char *key = NULL;
char *value;
assert(device);
assert(str);
key = strdup(str);
if (!key)
return -ENOMEM;
value = strchr(key, '=');
if (!value)
return -EINVAL;
*value = '\0';
if (isempty(++value))
value = NULL;
return device_add_property_internal(device, key, value);
}
int device_set_usec_initialized(sd_device *device, const char *initialized) {
uint64_t usec_initialized;
int r;
assert(device);
assert(initialized);
r = safe_atou64(initialized, &usec_initialized);
if (r < 0)
return r;
r = device_add_property_internal(device, "USEC_INITIALIZED", initialized);
if (r < 0)
return r;
device->usec_initialized = usec_initialized;
return 0;
}
static int handle_db_line(sd_device *device, char key, const char *value) {
char *path;
int r;
assert(device);
assert(value);
switch (key) {
case 'G':
r = device_add_tag(device, value);
if (r < 0)
return r;
break;
case 'S':
path = strjoina("/dev/", value);
r = device_add_devlink(device, path);
if (r < 0)
return r;
break;
case 'E':
r = device_add_property_internal_from_string(device, value);
if (r < 0)
return r;
break;
case 'I':
r = device_set_usec_initialized(device, value);
if (r < 0)
return r;
break;
case 'L':
r = safe_atoi(value, &device->devlink_priority);
if (r < 0)
return r;
break;
case 'W':
r = safe_atoi(value, &device->watch_handle);
if (r < 0)
return r;
break;
default:
log_debug("device db: unknown key '%c'", key);
}
return 0;
}
int device_get_id_filename(sd_device *device, const char **ret) {
assert(device);
assert(ret);
if (!device->id_filename) {
_cleanup_free_ char *id = NULL;
const char *subsystem;
dev_t devnum;
int ifindex, r;
r = sd_device_get_subsystem(device, &subsystem);
if (r < 0)
return r;
r = sd_device_get_devnum(device, &devnum);
if (r < 0)
return r;
r = sd_device_get_ifindex(device, &ifindex);
if (r < 0)
return r;
if (major(devnum) > 0) {
/* use dev_t -- b259:131072, c254:0 */
r = asprintf(&id, "%c%u:%u",
streq(subsystem, "block") ? 'b' : 'c',
major(devnum), minor(devnum));
if (r < 0)
return -errno;
} else if (ifindex > 0) {
/* use netdev ifindex -- n3 */
r = asprintf(&id, "n%u", ifindex);
if (r < 0)
return -errno;
} else {
/* use $subsys:$sysname -- pci:0000:00:1f.2
* sysname() has '!' translated, get it from devpath
*/
const char *sysname;
sysname = basename(device->devpath);
if (!sysname)
return -EINVAL;
r = asprintf(&id, "+%s:%s", subsystem, sysname);
if (r < 0)
return -errno;
}
device->id_filename = id;
id = NULL;
}
*ret = device->id_filename;
return 0;
}
static int device_read_db(sd_device *device) {
_cleanup_free_ char *db = NULL;
char *path;
const char *id, *value;
char key;
size_t db_len;
unsigned i;
int r;
enum {
PRE_KEY,
KEY,
PRE_VALUE,
VALUE,
INVALID_LINE,
} state = PRE_KEY;
if (device->db_loaded || device->sealed)
return 0;
r = device_get_id_filename(device, &id);
if (r < 0)
return r;
path = strjoina("/run/udev/data/", id);
r = read_full_file(path, &db, &db_len);
if (r < 0) {
if (r == -ENOENT)
return 0;
else {
log_debug("sd-device: failed to read db '%s': %s", path, strerror(-r));
return r;
}
}
/* devices with a database entry are initialized */
device->is_initialized = true;;
for (i = 0; i < db_len; i++) {
switch (state) {
case PRE_KEY:
if (!strchr(NEWLINE, db[i])) {
key = db[i];
state = KEY;
}
break;
case KEY:
if (db[i] != ':') {
log_debug("sd-device: ignoring invalid db entry with key '%c'", key);
state = INVALID_LINE;
} else {
db[i] = '\0';
state = PRE_VALUE;
}
break;
case PRE_VALUE:
value = &db[i];
state = VALUE;
break;
case INVALID_LINE:
if (strchr(NEWLINE, db[i]))
state = PRE_KEY;
break;
case VALUE:
if (strchr(NEWLINE, db[i])) {
db[i] = '\0';
r = handle_db_line(device, key, value);
if (r < 0)
log_debug("sd-device: failed to handle db entry '%c:%s': %s", key, value, strerror(-r));
state = PRE_KEY;
}
break;
default:
assert_not_reached("invalid state when parsing db");
}
}
device->db_loaded = true;
return 0;
}
_public_ int sd_device_get_is_initialized(sd_device *device, int *initialized) {
int r;
assert_return(device, -EINVAL);
assert_return(initialized, -EINVAL);
r = device_read_db(device);
if (r < 0)
return r;
*initialized = device->is_initialized;
return 0;
}
_public_ int sd_device_get_usec_since_initialized(sd_device *device, uint64_t *usec) {
usec_t now_ts;
int r;
assert_return(device, -EINVAL);
assert_return(usec, -EINVAL);
r = device_read_db(device);
if (r < 0)
return r;
if (!device->is_initialized)
return -EBUSY;
if (!device->usec_initialized)
return -ENODATA;
now_ts = now(clock_boottime_or_monotonic());
if (now_ts < device->usec_initialized)
return -EIO;
*usec = now_ts - device->usec_initialized;
return 0;
}
_public_ const char *sd_device_get_tag_first(sd_device *device) {
assert_return(device, NULL);
(void) device_read_db(device);
device->tags_iterator_generation = device->tags_generation;
device->tags_iterator = ITERATOR_FIRST;
return set_iterate(device->tags, &device->tags_iterator);
}
_public_ const char *sd_device_get_tag_next(sd_device *device) {
assert_return(device, NULL);
(void) device_read_db(device);
if (device->tags_iterator_generation != device->tags_generation)
return NULL;
return set_iterate(device->tags, &device->tags_iterator);
}
_public_ const char *sd_device_get_devlink_first(sd_device *device) {
assert_return(device, NULL);
(void) device_read_db(device);
device->devlinks_iterator_generation = device->devlinks_generation;
device->devlinks_iterator = ITERATOR_FIRST;
return set_iterate(device->devlinks, &device->devlinks_iterator);
}
_public_ const char *sd_device_get_devlink_next(sd_device *device) {
assert_return(device, NULL);
(void) device_read_db(device);
if (device->devlinks_iterator_generation != device->devlinks_generation)
return NULL;
return set_iterate(device->devlinks, &device->devlinks_iterator);
}
static int device_properties_prepare(sd_device *device) {
int r;
assert(device);
r = device_read_uevent_file(device);
if (r < 0)
return r;
r = device_read_db(device);
if (r < 0)
return r;
if (device->property_devlinks_outdated) {
char *devlinks = NULL;
const char *devlink;
devlink = sd_device_get_devlink_first(device);
if (devlink)
devlinks = strdupa(devlink);
while ((devlink = sd_device_get_devlink_next(device)))
devlinks = strjoina(devlinks, " ", devlink);
r = device_add_property_internal(device, "DEVLINKS", devlinks);
if (r < 0)
return r;
device->property_devlinks_outdated = false;
}
if (device->property_tags_outdated) {
char *tags = NULL;
const char *tag;
tag = sd_device_get_tag_first(device);
if (tag)
tags = strjoina(":", tag);
while ((tag = sd_device_get_tag_next(device)))
tags = strjoina(tags, ":", tag);
tags = strjoina(tags, ":");
r = device_add_property_internal(device, "TAGS", tags);
if (r < 0)
return r;
device->property_tags_outdated = false;
}
return 0;
}
_public_ const char *sd_device_get_property_first(sd_device *device, const char **_value) {
const char *key;
const char *value;
int r;
assert_return(device, NULL);
r = device_properties_prepare(device);
if (r < 0)
return NULL;
device->properties_iterator_generation = device->properties_generation;
device->properties_iterator = ITERATOR_FIRST;
value = ordered_hashmap_iterate(device->properties, &device->properties_iterator, (const void**)&key);
if (_value)
*_value = value;
return key;
}
_public_ const char *sd_device_get_property_next(sd_device *device, const char **_value) {
const char *key;
const char *value;
int r;
assert_return(device, NULL);
r = device_properties_prepare(device);
if (r < 0)
return NULL;
if (device->properties_iterator_generation != device->properties_generation)
return NULL;
value = ordered_hashmap_iterate(device->properties, &device->properties_iterator, (const void**)&key);
if (_value)
*_value = value;
return key;
}
static int device_sysattrs_read_all(sd_device *device) {
_cleanup_closedir_ DIR *dir = NULL;
const char *syspath;
struct dirent *dent;
int r;
assert(device);
if (device->sysattrs_read)
return 0;
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
dir = opendir(syspath);
if (!dir)
return -errno;
r = set_ensure_allocated(&device->sysattrs, &string_hash_ops);
if (r < 0)
return r;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
char *path;
struct stat statbuf;
/* only handle symlinks and regular files */
if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
continue;
path = strjoina(syspath, "/", dent->d_name);
if (lstat(path, &statbuf) != 0)
continue;
if (!(statbuf.st_mode & S_IRUSR))
continue;
r = set_put_strdup(device->sysattrs, dent->d_name);
if (r < 0)
return r;
}
device->sysattrs_read = true;
return 0;
}
_public_ const char *sd_device_get_sysattr_first(sd_device *device) {
int r;
assert_return(device, NULL);
if (!device->sysattrs_read) {
r = device_sysattrs_read_all(device);
if (r < 0) {
errno = -r;
return NULL;
}
}
device->sysattrs_iterator = ITERATOR_FIRST;
return set_iterate(device->sysattrs, &device->sysattrs_iterator);
}
_public_ const char *sd_device_get_sysattr_next(sd_device *device) {
assert_return(device, NULL);
if (!device->sysattrs_read)
return NULL;
return set_iterate(device->sysattrs, &device->sysattrs_iterator);
}
_public_ int sd_device_has_tag(sd_device *device, const char *tag) {
assert_return(device, -EINVAL);
assert_return(tag, -EINVAL);
(void) device_read_db(device);
return !!set_contains(device->tags, tag);
}
_public_ int sd_device_get_property_value(sd_device *device, const char *key, const char **_value) {
char *value;
int r;
assert_return(device, -EINVAL);
assert_return(key, -EINVAL);
assert_return(_value, -EINVAL);
r = device_properties_prepare(device);
if (r < 0)
return r;
value = ordered_hashmap_get(device->properties, key);
if (!value)
return -ENOENT;
*_value = value;
return 0;
}
/* replaces the value if it already exists */
static int device_add_sysattr_value(sd_device *device, const char *_key, char *value) {
_cleanup_free_ char *key = NULL;
_cleanup_free_ char *value_old = NULL;
int r;
assert(device);
assert(_key);
r = hashmap_ensure_allocated(&device->sysattr_values, &string_hash_ops);
if (r < 0)
return r;
value_old = hashmap_remove2(device->sysattr_values, _key, (void **)&key);
if (!key) {
key = strdup(_key);
if (!key)
return -ENOMEM;
}
r = hashmap_put(device->sysattr_values, key, value);
if (r < 0)
return r;
key = NULL;
return 0;
}
static int device_get_sysattr_value(sd_device *device, const char *_key, const char **_value) {
const char *key = NULL, *value;
assert(device);
assert(_key);
value = hashmap_get2(device->sysattr_values, _key, (void **) &key);
if (!key)
return -ENOENT;
if (_value)
*_value = value;
return 0;
}
/* We cache all sysattr lookups. If an attribute does not exist, it is stored
* with a NULL value in the cache, otherwise the returned string is stored */
_public_ int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value) {
_cleanup_free_ char *value = NULL;
const char *syspath, *cached_value = NULL;
char *path;
struct stat statbuf;
int r;
assert_return(device, -EINVAL);
assert_return(sysattr, -EINVAL);
/* look for possibly already cached result */
r = device_get_sysattr_value(device, sysattr, &cached_value);
if (r != -ENOENT) {
if (r < 0)
return r;
if (!cached_value)
/* we looked up the sysattr before and it did not exist */
return -ENOENT;
if (_value)
*_value = cached_value;
return 0;
}
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
path = strjoina(syspath, "/", sysattr);
r = lstat(path, &statbuf);
if (r < 0) {
/* remember that we could not access the sysattr */
r = device_add_sysattr_value(device, sysattr, NULL);
if (r < 0)
return r;
return -ENOENT;
} else if (S_ISLNK(statbuf.st_mode)) {
/* Some core links return only the last element of the target path,
* these are just values, the paths should not be exposed. */
if (STR_IN_SET(sysattr, "driver", "subsystem", "module")) {
r = readlink_value(path, &value);
if (r < 0)
return r;
} else
return -EINVAL;
} else if (S_ISDIR(statbuf.st_mode)) {
/* skip directories */
return -EINVAL;
} else if (!(statbuf.st_mode & S_IRUSR)) {
/* skip non-readable files */
return -EPERM;
} else {
size_t size;
/* read attribute value */
r = read_full_file(path, &value, &size);
if (r < 0)
return r;
/* drop trailing newlines */
while (size > 0 && value[--size] == '\n')
value[size] = '\0';
}
r = device_add_sysattr_value(device, sysattr, value);
if (r < 0)
return r;
*_value = value;
value = NULL;
return 0;
}
static void device_remove_sysattr_value(sd_device *device, const char *_key) {
_cleanup_free_ char *key = NULL;
_cleanup_free_ char *value = NULL;
assert(device);
assert(_key);
value = hashmap_remove2(device->sysattr_values, _key, (void **) &key);
return;
}
/* set the attribute and save it in the cache. If a NULL value is passed the
* attribute is cleared from the cache */
_public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, char *_value) {
_cleanup_close_ int fd = -1;
_cleanup_free_ char *value = NULL;
const char *syspath;
char *path;
struct stat statbuf;
size_t value_len = 0;
ssize_t size;
int r;
assert_return(device, -EINVAL);
assert_return(sysattr, -EINVAL);
if (!_value) {
device_remove_sysattr_value(device, sysattr);
return 0;
}
r = sd_device_get_syspath(device, &syspath);
if (r < 0)
return r;
path = strjoina(syspath, "/", sysattr);
r = lstat(path, &statbuf);
if (r < 0) {
value = strdup("");
if (!value)
return -ENOMEM;
r = device_add_sysattr_value(device, sysattr, value);
if (r < 0)
return r;
return -ENXIO;
}
if (S_ISLNK(statbuf.st_mode))
return -EINVAL;
/* skip directories */
if (S_ISDIR(statbuf.st_mode))
return -EISDIR;
/* skip non-readable files */
if ((statbuf.st_mode & S_IRUSR) == 0)
return -EACCES;
value_len = strlen(_value);
/* drop trailing newlines */
while (value_len > 0 && _value[value_len - 1] == '\n')
_value[--value_len] = '\0';
/* value length is limited to 4k */
if (value_len > 4096)
return -EINVAL;
fd = open(path, O_WRONLY | O_CLOEXEC);
if (fd < 0)
return -errno;
value = strdup(_value);
if (!value)
return -ENOMEM;
size = write(fd, value, value_len);
if (size < 0)
return -errno;
if ((size_t)size != value_len)
return -EIO;
r = device_add_sysattr_value(device, sysattr, value);
if (r < 0)
return r;
value = NULL;
return 0;
}