diff options
Diffstat (limited to 'udev/lib/libudev.c')
-rw-r--r-- | udev/lib/libudev.c | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/udev/lib/libudev.c b/udev/lib/libudev.c new file mode 100644 index 0000000000..098ca8f602 --- /dev/null +++ b/udev/lib/libudev.c @@ -0,0 +1,583 @@ +/* + * libudev - interface to udev device information + * + * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include "config.h" + +#include <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <unistd.h> +#include <errno.h> +#include <string.h> +#include <dirent.h> +#include <sys/stat.h> + +#include "libudev.h" +#include "libudev-private.h" +#include "../udev.h" + +void udev_log(struct udev *udev, + int priority, const char *file, int line, const char *fn, + const char *format, ...) +{ + va_list args; + + va_start(args, format); + udev->log_fn(udev, priority, file, line, fn, format, args); + va_end(args); +} + +static void log_stderr(struct udev *udev, + int priority, const char *file, int line, const char *fn, + const char *format, va_list args) +{ + static int log = -1; + + if (log == -1) { + if (getenv("LIBUDEV_DEBUG") != NULL) + log = 1; + else + log = 0; + } + + if (log == 1) { + fprintf(stderr, "libudev: %s: ", fn); + vfprintf(stderr, format, args); + } +} + +/* glue to udev logging, needed until udev logging code is "fixed" */ +#ifdef USE_LOG +void log_message(int priority, const char *format, ...) +{ + va_list args; + + va_start(args, format); + log_stderr(NULL, priority, NULL, 0, "", format, args); + va_end(args); +} +#endif + +static ssize_t get_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size) +{ + char path[PATH_SIZE]; + ssize_t len; + const char *pos; + + strlcpy(path, udev_get_sys_path(udev), sizeof(path)); + strlcat(path, devpath, sizeof(path)); + strlcat(path, "/subsystem", sizeof(path)); + len = readlink(path, path, sizeof(path)); + if (len < 0 || len >= (ssize_t) sizeof(path)) + return -1; + path[len] = '\0'; + pos = strrchr(path, '/'); + if (pos == NULL) + return -1; + pos = &pos[1]; + return strlcpy(subsystem, pos, size); +} + +/** + * udev_new: + * + * Create udev library context. + * + * The initial refcount is 1, and needs to be decremented to + * release the ressources of the udev library context. + * + * Returns: a new udev library context + **/ +struct udev *udev_new(void) +{ + struct udev *udev; + + udev = malloc(sizeof(struct udev)); + if (udev == NULL) + return NULL; + memset(udev, 0x00, (sizeof(struct udev))); + udev->refcount = 1; + udev->log_fn = log_stderr; + udev_config_init(); + sysfs_init(); + log_info(udev, "context %p created\n", udev); + return udev; +} + +/** + * udev_ref: + * @udev: udev library context + * + * Take a reference of the udev library context. + * + * Returns: the passed udev library context + **/ +struct udev *udev_ref(struct udev *udev) +{ + udev->refcount++; + return udev; +} + +/** + * udev_unref: + * @udev: udev library context + * + * Drop a reference of the udev library context. If the refcount + * reaches zero, the ressources of the context will be released. + * + **/ +void udev_unref(struct udev *udev) +{ + udev->refcount--; + if (udev->refcount > 0) + return; + sysfs_cleanup(); + log_info(udev, "context %p released\n", udev); + free(udev); +} + +/** + * udev_set_log_fn: + * @udev: udev library context + * @log_fn: function to be called for logging messages + * + * The built-in logging, which writes to stderr if the + * LIBUDEV_DEBUG environment variable is set, can be + * overridden by a custom function, to plug log messages + * into the users logging functionality. + * + **/ +void udev_set_log_fn(struct udev *udev, + void (*log_fn)(struct udev *udev, + int priority, const char *file, int line, const char *fn, + const char *format, va_list args)) +{ + udev->log_fn = log_fn; + log_info(udev, "custom logging function %p registered\n", udev); +} + +/** + * udev_get_sys_path: + * @udev: udev library context + * + * Retrieve the sysfs mount point. The default is "/sys". For + * testing purposes, it can be overridden with the environment + * variable SYSFS_PATH. + * + * Returns: the sys mount point + **/ +const char *udev_get_sys_path(struct udev *udev) +{ + return sysfs_path; +} + +/** + * udev_get_dev_path: + * @udev: udev library context + * + * Retrieve the device directory path. The default value is "/dev", + * the actual value may be overridden in the udev configuration + * file. + * + * Returns: the device directory path + **/ +const char *udev_get_dev_path(struct udev *udev) +{ + return udev_root; +} + +static struct udev_device *device_init(struct udev *udev) +{ + struct udev_device *udev_device; + + udev_device = malloc(sizeof(struct udev_device)); + if (udev_device == NULL) + return NULL; + memset(udev_device, 0x00, sizeof(struct udev_device)); + udev_device->refcount = 1; + udev_device->udev = udev; + return udev_device; +} + +/** + * udev_device_new_from_devpath: + * @udev: udev library context + * @devpath: sys device path + * + * Create new udev device, and fill in information from the sysfs + * device and the udev database entry. The devpath must not contain + * the sysfs mount path, and must contain a leading '/'. + * + * The initial refcount is 1, and needs to be decremented to + * release the ressources of the udev device. + * + * Returns: a new udev device, or #NULL, if it does not exist + **/ +struct udev_device *udev_device_new_from_devpath(struct udev *udev, const char *devpath) +{ + char path[PATH_SIZE]; + struct stat statbuf; + struct udev_device *udev_device; + int err; + + strlcpy(path, udev_get_sys_path(udev), sizeof(path)); + strlcat(path, devpath, sizeof(path)); + if (stat(path, &statbuf) != 0) + return NULL; + if (!S_ISDIR(statbuf.st_mode)) + return NULL; + + udev_device = device_init(udev); + if (udev_device == NULL) + return NULL; + + udev_device->udevice = udev_device_init(NULL); + if (udev_device->udevice == NULL) { + free(udev_device); + return NULL; + } + log_info(udev, "device %p created\n", udev_device); + + strlcpy(path, devpath, sizeof(path)); + sysfs_resolve_link(path, sizeof(path)); + + err = udev_db_get_device(udev_device->udevice, path); + if (err >= 0) + log_info(udev, "device %p filled with udev database data\n", udev_device); + log_info(udev, "device %p filled with %s data\n", udev_device, udev_device_get_devpath(udev_device)); + return udev_device; +} + +/** + * udev_device_get_udev: + * + * Retrieve the udev library context the device was created with. + * + * Returns: the udev library context + **/ +struct udev *udev_device_get_udev(struct udev_device *udev_device) +{ + return udev_device->udev; +} + +/** + * udev_device_ref: + * @udev_device: udev device + * + * Take a reference of a udev device. + * + * Returns: the passed udev device + **/ +struct udev_device *udev_device_ref(struct udev_device *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 ressources of the device will be released. + * + **/ +void udev_device_unref(struct udev_device *udev_device) +{ + udev_device->refcount--; + if (udev_device->refcount > 0) + return; + udev_device_cleanup(udev_device->udevice); + free(udev_device); +} + +/** + * udev_device_get_devpath: + * @udev_device: udev device + * + * Retrieve the sys path of the udev device. The path does not contain + * the sys mount point. + * + * Returns: the sys path of the udev device + **/ +const char *udev_device_get_devpath(struct udev_device *udev_device) +{ + return udev_device->udevice->dev->devpath; +} + +/** + * udev_device_get_devname: + * @udev_device: udev device + * + * Retrieve the device node file name belonging to the udev device. + * The path does not contain the device directory, and does not contain + * a leading '/'. + * + * Returns: the device node file name of the udev device, or #NULL if no device node exists + **/ +const char *udev_device_get_devname(struct udev_device *udev_device) +{ + if (udev_device->udevice->name[0] == '\0') + return NULL; + return udev_device->udevice->name; +} + +/** + * 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 + **/ +const char *udev_device_get_subsystem(struct udev_device *udev_device) +{ + struct sysfs_device *dev = udev_device->udevice->dev; + if (dev->subsystem[0] != '\0') + return dev->subsystem; + if (get_subsystem(udev_device->udev, dev->devpath, + dev->subsystem, sizeof(dev->subsystem)) < 2) + return NULL; + return dev->subsystem; +} + +/** + * udev_device_get_devlinks: + * @udev_device: udev device + * @cb: function to be called for every device link found + * @data: data to be passed to the function + * + * Retrieve the device links pointing to the device file of the + * udev device. For every device link, the passed function will be + * called with the device link string. If the function returns 1, + * remaning device links will be ignored. The device link path + * does not contain the device directory, and does not contain + * a leading '/'. + * + * Returns: the number of device links passed to the caller, or a negative value on error + **/ +int udev_device_get_devlinks(struct udev_device *udev_device, + int (*cb)(struct udev_device *udev_device, const char *value, void *data), + void *data) +{ + struct name_entry *name_loop; + int count = 0; + + list_for_each_entry(name_loop, &udev_device->udevice->symlink_list, node) { + count++; + if (cb(udev_device, name_loop->name, data) != 0) + break; + } + return count; +} + +/** + * udev_device_get_properties: + * @udev_device: udev device + * @cb: function to be called for every property found + * @data: data to be passed to the function + * + * Retrieve the property key/value pairs belonging to the + * udev device. For every key/value pair, the passed function will be + * called. If the function returns 1, remaning properties will be + * ignored. + * + * Returns: the number of properties passed to the caller, or a negative value on error + **/ +int udev_device_get_properties(struct udev_device *udev_device, + int (*cb)(struct udev_device *udev_device, const char *key, const char *value, void *data), + void *data) +{ + struct name_entry *name_loop; + int count = 0; + + list_for_each_entry(name_loop, &udev_device->udevice->env_list, node) { + char name[PATH_SIZE]; + char *val; + + strncpy(name, name_loop->name, PATH_SIZE); + name[PATH_SIZE-1] = '\0'; + val = strchr(name, '='); + if (val == NULL) + continue; + val[0] = '\0'; + val = &val[1]; + if (cb(udev_device, name, val, data) != 0) + break; + } + return count; +} + +static int devices_scan_subsystem(struct udev *udev, + const char *basedir, const char *subsystem, const char *subdir, + struct list_head *device_list) +{ + char path[PATH_SIZE]; + DIR *dir; + struct dirent *dent; + size_t len; + + len = strlcpy(path, udev_get_sys_path(udev), sizeof(path)); + strlcat(path, basedir, sizeof(path)); + strlcat(path, "/", sizeof(path)); + strlcat(path, subsystem, sizeof(path)); + if (subdir != NULL) + strlcat(path, subdir, sizeof(path)); + dir = opendir(path); + if (dir == NULL) + return -1; + for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) { + char devpath[PATH_SIZE]; + + if (dent->d_name[0] == '.') + continue; + strlcpy(devpath, &path[len], sizeof(devpath)); + strlcat(devpath, "/", sizeof(devpath)); + strlcat(devpath, dent->d_name, sizeof(devpath)); + sysfs_resolve_link(devpath, sizeof(devpath)); + name_list_add(device_list, devpath, 1); + } + closedir(dir); + return 0; +} + +static int devices_scan_subsystems(struct udev *udev, + const char *basedir, const char *subsystem, const char *subdir, + struct list_head *device_list) +{ + char path[PATH_SIZE]; + DIR *dir; + struct dirent *dent; + + if (subsystem != NULL) + return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list); + + strlcpy(path, udev_get_sys_path(udev), sizeof(path)); + strlcat(path, basedir, sizeof(path)); + dir = opendir(path); + if (dir == NULL) + return -1; + for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) { + if (dent->d_name[0] == '.') + continue; + devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list); + } + closedir(dir); + return 0; +} + +static int devices_delay(struct udev *udev, const char *devpath) +{ + static const char *delay_device_list[] = { + "/block/md", + "/block/dm-", + NULL + }; + int i; + + for (i = 0; delay_device_list[i] != NULL; i++) { + if (strstr(devpath, delay_device_list[i]) != NULL) { + log_info(udev, "delaying: %s\n", devpath); + return 1; + } + } + return 0; +} + +static int devices_call(struct udev *udev, const char *devpath, + int (*cb)(struct udev *udev, + const char *devpath, const char *subsystem, const char *name, + void *data), + void *data, + int *cb_rc) +{ + char subsystem[NAME_SIZE]; + const char *name; + + name = strrchr(devpath, '/'); + if (name == NULL) + return -1; + name++; + + if (get_subsystem(udev, devpath, subsystem, sizeof(subsystem)) < 2) + return -1; + *cb_rc = cb(udev, devpath, subsystem, name, data); + return 0; +} + +/** + * udev_devices_enumerate: + * @udev_device: udev device + * @cb: function to be called for every property found + * @data: data to be passed to the function + * + * Retrieve the property key/value pairs belonging to the + * udev device. For every key/value pair, the passed function will be + * called. If the function returns 1, remaning properties will be + * ignored. + * + * Returns: the number of properties passed to the caller, or a negative value on error + **/ +int udev_devices_enumerate(struct udev *udev, const char *subsystem, + int (*cb)(struct udev *udev, + const char *devpath, const char *subsystem, const char *name, void *data), + void *data) +{ + char base[PATH_SIZE]; + struct stat statbuf; + struct list_head device_list; + struct name_entry *loop_device; + struct name_entry *tmp_device; + int cb_rc = 0; + int count = 0; + + INIT_LIST_HEAD(&device_list); + + /* if we have /sys/subsystem/, forget all the old stuff */ + strlcpy(base, sysfs_path, sizeof(base)); + strlcat(base, "/subsystem", sizeof(base)); + if (stat(base, &statbuf) == 0) { + devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list); + } else { + devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list); + devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list); + } + + list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) { + if (devices_delay(udev, loop_device->name)) + continue; + if (cb_rc == 0) + if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0) + count++; + list_del(&loop_device->node); + free(loop_device); + } + + /* handle remaining delayed devices */ + list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) { + if (cb_rc == 0) + if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0) + count++; + list_del(&loop_device->node); + free(loop_device); + } + + return count; +} |