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Diffstat (limited to 'src/libudev/src/libudev-device.c')
| -rw-r--r-- | src/libudev/src/libudev-device.c | 960 |
1 files changed, 960 insertions, 0 deletions
diff --git a/src/libudev/src/libudev-device.c b/src/libudev/src/libudev-device.c new file mode 100644 index 0000000000..d6e2c5fa6e --- /dev/null +++ b/src/libudev/src/libudev-device.c @@ -0,0 +1,960 @@ +/*** + This file is part of systemd. + + Copyright 2008-2012 Kay Sievers <kay@vrfy.org> + Copyright 2015 Tom Gundersen <teg@jklm.no> + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <ctype.h> +#include <dirent.h> +#include <errno.h> +#include <fcntl.h> +#include <net/if.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <linux/sockios.h> + +#include <libudev.h> + +#include "sd-device/device-private.h" +#include "sd-device/device-util.h" +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/parse-util.h" +#include "systemd-staging/sd-device.h" + +#include "libudev-device-internal.h" +#include "libudev-private.h" + +/** + * SECTION:libudev-device + * @short_description: kernel sys devices + * + * Representation of kernel sys devices. Devices are uniquely identified + * by their syspath, every device has exactly one path in the kernel sys + * filesystem. Devices usually belong to a kernel subsystem, and have + * a unique name inside that subsystem. + */ + +/** + * udev_device_get_seqnum: + * @udev_device: udev device + * + * This is only valid if the device was received through a monitor. Devices read from + * sys do not have a sequence number. + * + * Returns: the kernel event sequence number, or 0 if there is no sequence number available. + **/ +_public_ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device) +{ + const char *seqnum; + unsigned long long ret; + int r; + + assert_return_errno(udev_device, 0, EINVAL); + + r = sd_device_get_property_value(udev_device->device, "SEQNUM", &seqnum); + if (r == -ENOENT) + return 0; + else if (r < 0) { + errno = -r; + return 0; + } + + r = safe_atollu(seqnum, &ret); + if (r < 0) { + errno = -r; + return 0; + } + + return ret; +} + +/** + * udev_device_get_devnum: + * @udev_device: udev device + * + * Get the device major/minor number. + * + * Returns: the dev_t number. + **/ +_public_ dev_t udev_device_get_devnum(struct udev_device *udev_device) +{ + dev_t devnum; + int r; + + assert_return_errno(udev_device, makedev(0, 0), EINVAL); + + r = sd_device_get_devnum(udev_device->device, &devnum); + if (r < 0) { + errno = -r; + return makedev(0, 0); + } + + return devnum; +} + +/** + * udev_device_get_driver: + * @udev_device: udev device + * + * Get the kernel driver name. + * + * Returns: the driver name string, or #NULL if there is no driver attached. + **/ +_public_ const char *udev_device_get_driver(struct udev_device *udev_device) +{ + const char *driver; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_driver(udev_device->device, &driver); + if (r < 0) { + errno = -r; + return NULL; + } + + return driver; +} + +/** + * udev_device_get_devtype: + * @udev_device: udev device + * + * Retrieve the devtype string of the udev device. + * + * Returns: the devtype name of the udev device, or #NULL if it can not be determined + **/ +_public_ const char *udev_device_get_devtype(struct udev_device *udev_device) +{ + const char *devtype; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_devtype(udev_device->device, &devtype); + if (r < 0) { + errno = -r; + return NULL; + } + + return devtype; +} + +/** + * udev_device_get_subsystem: + * @udev_device: udev device + * + * Retrieve the subsystem string of the udev device. The string does not + * contain any "/". + * + * Returns: the subsystem name of the udev device, or #NULL if it can not be determined + **/ +_public_ const char *udev_device_get_subsystem(struct udev_device *udev_device) +{ + const char *subsystem; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_subsystem(udev_device->device, &subsystem); + if (r < 0) { + errno = -r; + return NULL; + } else if (!subsystem) + errno = ENODATA; + + return subsystem; +} + +/** + * udev_device_get_property_value: + * @udev_device: udev device + * @key: property name + * + * Get the value of a given property. + * + * Returns: the property string, or #NULL if there is no such property. + **/ +_public_ const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key) +{ + const char *value = NULL; + int r; + + assert_return_errno(udev_device && key, NULL, EINVAL); + + r = sd_device_get_property_value(udev_device->device, key, &value); + if (r < 0) { + errno = -r; + return NULL; + } + + return value; +} + +struct udev_device *udev_device_new(struct udev *udev) { + struct udev_device *udev_device; + + assert_return_errno(udev, NULL, EINVAL); + + udev_device = new0(struct udev_device, 1); + if (!udev_device) { + errno = ENOMEM; + return NULL; + } + udev_device->refcount = 1; + udev_device->udev = udev; + udev_list_init(udev, &udev_device->properties, true); + udev_list_init(udev, &udev_device->tags, true); + udev_list_init(udev, &udev_device->sysattrs, true); + udev_list_init(udev, &udev_device->devlinks, true); + + return udev_device; +} + +/** + * udev_device_new_from_syspath: + * @udev: udev library context + * @syspath: sys device path including sys directory + * + * Create new udev device, and fill in information from the sys + * device and the udev database entry. The syspath is the absolute + * path to the device, including the sys mount point. + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +_public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath) { + struct udev_device *udev_device; + int r; + + udev_device = udev_device_new(udev); + if (!udev_device) + return NULL; + + r = sd_device_new_from_syspath(&udev_device->device, syspath); + if (r < 0) { + errno = -r; + udev_device_unref(udev_device); + return NULL; + } + + return udev_device; +} + +/** + * udev_device_new_from_devnum: + * @udev: udev library context + * @type: char or block device + * @devnum: device major/minor number + * + * Create new udev device, and fill in information from the sys + * device and the udev database entry. The device is looked-up + * by its major/minor number and type. Character and block device + * numbers are not unique across the two types. + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +_public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum) +{ + struct udev_device *udev_device; + int r; + + udev_device = udev_device_new(udev); + if (!udev_device) + return NULL; + + r = sd_device_new_from_devnum(&udev_device->device, type, devnum); + if (r < 0) { + errno = -r; + udev_device_unref(udev_device); + return NULL; + } + + return udev_device; +} + +/** + * udev_device_new_from_device_id: + * @udev: udev library context + * @id: text string identifying a kernel device + * + * Create new udev device, and fill in information from the sys + * device and the udev database entry. The device is looked-up + * by a special string: + * b8:2 - block device major:minor + * c128:1 - char device major:minor + * n3 - network device ifindex + * +sound:card29 - kernel driver core subsystem:device name + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +_public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id) +{ + struct udev_device *udev_device; + int r; + + udev_device = udev_device_new(udev); + if (!udev_device) + return NULL; + + r = sd_device_new_from_device_id(&udev_device->device, id); + if (r < 0) { + errno = -r; + udev_device_unref(udev_device); + return NULL; + } + + return udev_device; +} + +/** + * udev_device_new_from_subsystem_sysname: + * @udev: udev library context + * @subsystem: the subsystem of the device + * @sysname: the name of the device + * + * Create new udev device, and fill in information from the sys device + * and the udev database entry. The device is looked up by the subsystem + * and name string of the device, like "mem" / "zero", or "block" / "sda". + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +_public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname) +{ + struct udev_device *udev_device; + int r; + + udev_device = udev_device_new(udev); + if (!udev_device) + return NULL; + + r = sd_device_new_from_subsystem_sysname(&udev_device->device, subsystem, sysname); + if (r < 0) { + errno = -r; + udev_device_unref(udev_device); + return NULL; + } + + return udev_device; +} + +/** + * udev_device_new_from_environment + * @udev: udev library context + * + * Create new udev device, and fill in information from the + * current process environment. This only works reliable if + * the process is called from a udev rule. It is usually used + * for tools executed from IMPORT= rules. + * + * The initial refcount is 1, and needs to be decremented to + * release the resources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +_public_ struct udev_device *udev_device_new_from_environment(struct udev *udev) +{ + struct udev_device *udev_device; + int r; + + udev_device = udev_device_new(udev); + if (!udev_device) + return NULL; + + r = device_new_from_strv(&udev_device->device, environ); + if (r < 0) { + errno = -r; + udev_device_unref(udev_device); + return NULL; + } + + return udev_device; +} + +static struct udev_device *device_new_from_parent(struct udev_device *child) +{ + struct udev_device *parent; + int r; + + assert_return_errno(child, NULL, EINVAL); + + parent = udev_device_new(child->udev); + if (!parent) + return NULL; + + r = sd_device_get_parent(child->device, &parent->device); + if (r < 0) { + errno = -r; + udev_device_unref(parent); + return NULL; + } + + /* the parent is unref'ed with the child, so take a ref from libudev as well */ + sd_device_ref(parent->device); + + return parent; +} + +/** + * udev_device_get_parent: + * @udev_device: the device to start searching from + * + * Find the next parent device, and fill in information from the sys + * device and the udev database entry. + * + * Returned device is not referenced. It is attached to the child + * device, and will be cleaned up when the child device is cleaned up. + * + * It is not necessarily just the upper level directory, empty or not + * recognized sys directories are ignored. + * + * It can be called as many times as needed, without caring about + * references. + * + * Returns: a new udev device, or #NULL, if it no parent exist. + **/ +_public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + if (!udev_device->parent_set) { + udev_device->parent_set = true; + udev_device->parent = device_new_from_parent(udev_device); + } + + /* TODO: errno will differ here in case parent == NULL */ + return udev_device->parent; +} + +/** + * udev_device_get_parent_with_subsystem_devtype: + * @udev_device: udev device to start searching from + * @subsystem: the subsystem of the device + * @devtype: the type (DEVTYPE) of the device + * + * Find the next parent device, with a matching subsystem and devtype + * value, and fill in information from the sys device and the udev + * database entry. + * + * If devtype is #NULL, only subsystem is checked, and any devtype will + * match. + * + * Returned device is not referenced. It is attached to the child + * device, and will be cleaned up when the child device is cleaned up. + * + * It can be called as many times as needed, without caring about + * references. + * + * Returns: a new udev device, or #NULL if no matching parent exists. + **/ +_public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype) +{ + sd_device *parent; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + /* this relies on the fact that finding the subdevice of a parent or the + parent of a subdevice commute */ + + /* first find the correct sd_device */ + r = sd_device_get_parent_with_subsystem_devtype(udev_device->device, subsystem, devtype, &parent); + if (r < 0) { + errno = -r; + return NULL; + } + + /* then walk the chain of udev_device parents until the corresponding + one is found */ + while ((udev_device = udev_device_get_parent(udev_device))) { + if (udev_device->device == parent) + return udev_device; + } + + errno = ENOENT; + return NULL; +} + +/** + * udev_device_get_udev: + * @udev_device: udev device + * + * Retrieve the udev library context the device was created with. + * + * Returns: the udev library context + **/ +_public_ struct udev *udev_device_get_udev(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + return udev_device->udev; +} + +/** + * udev_device_ref: + * @udev_device: udev device + * + * Take a reference of a udev device. + * + * Returns: the passed udev device + **/ +_public_ struct udev_device *udev_device_ref(struct udev_device *udev_device) +{ + if (udev_device) + udev_device->refcount++; + + return udev_device; +} + +/** + * udev_device_unref: + * @udev_device: udev device + * + * Drop a reference of a udev device. If the refcount reaches zero, + * the resources of the device will be released. + * + * Returns: #NULL + **/ +_public_ struct udev_device *udev_device_unref(struct udev_device *udev_device) +{ + if (udev_device && (-- udev_device->refcount) == 0) { + sd_device_unref(udev_device->device); + udev_device_unref(udev_device->parent); + + udev_list_cleanup(&udev_device->properties); + udev_list_cleanup(&udev_device->sysattrs); + udev_list_cleanup(&udev_device->tags); + udev_list_cleanup(&udev_device->devlinks); + + free(udev_device); + } + + return NULL; +} + +/** + * udev_device_get_devpath: + * @udev_device: udev device + * + * Retrieve the kernel devpath value of the udev device. The path + * does not contain the sys mount point, and starts with a '/'. + * + * Returns: the devpath of the udev device + **/ +_public_ const char *udev_device_get_devpath(struct udev_device *udev_device) +{ + const char *devpath; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_devpath(udev_device->device, &devpath); + if (r < 0) { + errno = -r; + return NULL; + } + + return devpath; +} + +/** + * udev_device_get_syspath: + * @udev_device: udev device + * + * Retrieve the sys path of the udev device. The path is an + * absolute path and starts with the sys mount point. + * + * Returns: the sys path of the udev device + **/ +_public_ const char *udev_device_get_syspath(struct udev_device *udev_device) +{ + const char *syspath; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_syspath(udev_device->device, &syspath); + if (r < 0) { + errno = -r; + return NULL; + } + + return syspath; +} + +/** + * udev_device_get_sysname: + * @udev_device: udev device + * + * Get the kernel device name in /sys. + * + * Returns: the name string of the device + **/ +_public_ const char *udev_device_get_sysname(struct udev_device *udev_device) +{ + const char *sysname; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_sysname(udev_device->device, &sysname); + if (r < 0) { + errno = -r; + return NULL; + } + + return sysname; +} + +/** + * udev_device_get_sysnum: + * @udev_device: udev device + * + * Get the instance number of the device. + * + * Returns: the trailing number string of the device name + **/ +_public_ const char *udev_device_get_sysnum(struct udev_device *udev_device) +{ + const char *sysnum; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_sysnum(udev_device->device, &sysnum); + if (r < 0) { + errno = -r; + return NULL; + } + + return sysnum; +} + +/** + * udev_device_get_devnode: + * @udev_device: udev device + * + * Retrieve the device node file name belonging to the udev device. + * The path is an absolute path, and starts with the device directory. + * + * Returns: the device node file name of the udev device, or #NULL if no device node exists + **/ +_public_ const char *udev_device_get_devnode(struct udev_device *udev_device) +{ + const char *devnode; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_devname(udev_device->device, &devnode); + if (r < 0) { + errno = -r; + return NULL; + } + + return devnode; +} + +/** + * udev_device_get_devlinks_list_entry: + * @udev_device: udev device + * + * Retrieve the list of device links pointing to the device file of + * the udev device. The next list entry can be retrieved with + * udev_list_entry_get_next(), which returns #NULL if no more entries exist. + * The devlink path can be retrieved from the list entry by + * udev_list_entry_get_name(). The path is an absolute path, and starts with + * the device directory. + * + * Returns: the first entry of the device node link list + **/ +_public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + if (device_get_devlinks_generation(udev_device->device) != udev_device->devlinks_generation || + !udev_device->devlinks_read) { + const char *devlink; + + udev_list_cleanup(&udev_device->devlinks); + + FOREACH_DEVICE_DEVLINK(udev_device->device, devlink) + udev_list_entry_add(&udev_device->devlinks, devlink, NULL); + + udev_device->devlinks_read = true; + udev_device->devlinks_generation = device_get_devlinks_generation(udev_device->device); + } + + return udev_list_get_entry(&udev_device->devlinks); +} + +/** + * udev_device_get_event_properties_entry: + * @udev_device: udev device + * + * Retrieve the list of key/value device properties of the udev + * device. The next list entry can be retrieved with udev_list_entry_get_next(), + * which returns #NULL if no more entries exist. The property name + * can be retrieved from the list entry by udev_list_entry_get_name(), + * the property value by udev_list_entry_get_value(). + * + * Returns: the first entry of the property list + **/ +_public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + if (device_get_properties_generation(udev_device->device) != udev_device->properties_generation || + !udev_device->properties_read) { + const char *key, *value; + + udev_list_cleanup(&udev_device->properties); + + FOREACH_DEVICE_PROPERTY(udev_device->device, key, value) + udev_list_entry_add(&udev_device->properties, key, value); + + udev_device->properties_read = true; + udev_device->properties_generation = device_get_properties_generation(udev_device->device); + } + + return udev_list_get_entry(&udev_device->properties); +} + +/** + * udev_device_get_action: + * @udev_device: udev device + * + * This is only valid if the device was received through a monitor. Devices read from + * sys do not have an action string. Usual actions are: add, remove, change, online, + * offline. + * + * Returns: the kernel action value, or #NULL if there is no action value available. + **/ +_public_ const char *udev_device_get_action(struct udev_device *udev_device) { + const char *action = NULL; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_property_value(udev_device->device, "ACTION", &action); + if (r < 0 && r != -ENOENT) { + errno = -r; + return NULL; + } + + return action; +} + +/** + * udev_device_get_usec_since_initialized: + * @udev_device: udev device + * + * Return the number of microseconds passed since udev set up the + * device for the first time. + * + * This is only implemented for devices with need to store properties + * in the udev database. All other devices return 0 here. + * + * Returns: the number of microseconds since the device was first seen. + **/ +_public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device) +{ + usec_t ts; + int r; + + assert_return(udev_device, -EINVAL); + + r = sd_device_get_usec_since_initialized(udev_device->device, &ts); + if (r < 0) { + errno = EINVAL; + return 0; + } + + return ts; +} + +/** + * udev_device_get_sysattr_value: + * @udev_device: udev device + * @sysattr: attribute name + * + * The retrieved value is cached in the device. Repeated calls will return the same + * value and not open the attribute again. + * + * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value. + **/ +_public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr) +{ + const char *value; + int r; + + assert_return_errno(udev_device, NULL, EINVAL); + + r = sd_device_get_sysattr_value(udev_device->device, sysattr, &value); + if (r < 0) { + errno = -r; + return NULL; + } + + return value; +} + +/** + * udev_device_set_sysattr_value: + * @udev_device: udev device + * @sysattr: attribute name + * @value: new value to be set + * + * Update the contents of the sys attribute and the cached value of the device. + * + * Returns: Negative error code on failure or 0 on success. + **/ +_public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value) +{ + int r; + + assert_return(udev_device, -EINVAL); + + r = sd_device_set_sysattr_value(udev_device->device, sysattr, value); + if (r < 0) + return r; + + return 0; +} + +/** + * udev_device_get_sysattr_list_entry: + * @udev_device: udev device + * + * Retrieve the list of available sysattrs, with value being empty; + * This just return all available sysfs attributes for a particular + * device without reading their values. + * + * Returns: the first entry of the property list + **/ +_public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + if (!udev_device->sysattrs_read) { + const char *sysattr; + + udev_list_cleanup(&udev_device->sysattrs); + + FOREACH_DEVICE_SYSATTR(udev_device->device, sysattr) + udev_list_entry_add(&udev_device->sysattrs, sysattr, NULL); + + udev_device->sysattrs_read = true; + } + + return udev_list_get_entry(&udev_device->sysattrs); +} + +/** + * udev_device_get_is_initialized: + * @udev_device: udev device + * + * Check if udev has already handled the device and has set up + * device node permissions and context, or has renamed a network + * device. + * + * This is only implemented for devices with a device node + * or network interfaces. All other devices return 1 here. + * + * Returns: 1 if the device is set up. 0 otherwise. + **/ +_public_ int udev_device_get_is_initialized(struct udev_device *udev_device) +{ + int r, initialized; + + assert_return(udev_device, -EINVAL); + + r = sd_device_get_is_initialized(udev_device->device, &initialized); + if (r < 0) { + errno = -r; + + return 0; + } + + return initialized; +} + +/** + * udev_device_get_tags_list_entry: + * @udev_device: udev device + * + * Retrieve the list of tags attached to the udev device. The next + * list entry can be retrieved with udev_list_entry_get_next(), + * which returns #NULL if no more entries exist. The tag string + * can be retrieved from the list entry by udev_list_entry_get_name(). + * + * Returns: the first entry of the tag list + **/ +_public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device) +{ + assert_return_errno(udev_device, NULL, EINVAL); + + if (device_get_tags_generation(udev_device->device) != udev_device->tags_generation || + !udev_device->tags_read) { + const char *tag; + + udev_list_cleanup(&udev_device->tags); + + FOREACH_DEVICE_TAG(udev_device->device, tag) + udev_list_entry_add(&udev_device->tags, tag, NULL); + + udev_device->tags_read = true; + udev_device->tags_generation = device_get_tags_generation(udev_device->device); + } + + return udev_list_get_entry(&udev_device->tags); +} + +/** + * udev_device_has_tag: + * @udev_device: udev device + * @tag: tag name + * + * Check if a given device has a certain tag associated. + * + * Returns: 1 if the tag is found. 0 otherwise. + **/ +_public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag) +{ + assert_return(udev_device, 0); + + return sd_device_has_tag(udev_device->device, tag); +} |