511 lines
14 KiB
C
511 lines
14 KiB
C
/*
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* Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <ctype.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include "udev.h"
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char sysfs_path[PATH_SIZE];
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/* device cache */
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static LIST_HEAD(dev_list);
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/* attribute value cache */
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static LIST_HEAD(attr_list);
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struct sysfs_attr {
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struct list_head node;
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char path[PATH_SIZE];
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char *value; /* points to value_local if value is cached */
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char value_local[NAME_SIZE];
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};
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int sysfs_init(void)
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{
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const char *env;
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env = getenv("SYSFS_PATH");
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if (env) {
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strlcpy(sysfs_path, env, sizeof(sysfs_path));
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remove_trailing_chars(sysfs_path, '/');
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} else
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strlcpy(sysfs_path, "/sys", sizeof(sysfs_path));
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dbg("sysfs_path='%s'\n", sysfs_path);
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INIT_LIST_HEAD(&dev_list);
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INIT_LIST_HEAD(&attr_list);
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return 0;
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}
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void sysfs_cleanup(void)
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{
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struct sysfs_attr *attr_loop;
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struct sysfs_attr *attr_temp;
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struct sysfs_device *dev_loop;
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struct sysfs_device *dev_temp;
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list_for_each_entry_safe(attr_loop, attr_temp, &attr_list, node) {
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list_del(&attr_loop->node);
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free(attr_loop);
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}
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list_for_each_entry_safe(dev_loop, dev_temp, &dev_list, node) {
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list_del(&dev_loop->node);
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free(dev_loop);
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}
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}
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void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
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const char *subsystem, const char *driver)
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{
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char *pos;
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strlcpy(dev->devpath, devpath, sizeof(dev->devpath));
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if (subsystem != NULL)
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strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem));
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if (driver != NULL)
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strlcpy(dev->driver, driver, sizeof(dev->driver));
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/* set kernel name */
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pos = strrchr(dev->devpath, '/');
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if (pos == NULL)
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return;
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strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel));
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dbg("kernel='%s'\n", dev->kernel);
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/* some devices have '!' in their name, change that to '/' */
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pos = dev->kernel;
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while (pos[0] != '\0') {
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if (pos[0] == '!')
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pos[0] = '/';
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pos++;
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}
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/* get kernel number */
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pos = &dev->kernel[strlen(dev->kernel)];
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while (isdigit(pos[-1]))
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pos--;
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strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number));
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dbg("kernel_number='%s'\n", dev->kernel_number);
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}
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int sysfs_resolve_link(char *devpath, size_t size)
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{
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char link_path[PATH_SIZE];
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char link_target[PATH_SIZE];
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int len;
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int i;
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int back;
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strlcpy(link_path, sysfs_path, sizeof(link_path));
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strlcat(link_path, devpath, sizeof(link_path));
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len = readlink(link_path, link_target, sizeof(link_target));
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if (len <= 0)
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return -1;
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link_target[len] = '\0';
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dbg("path link '%s' points to '%s'\n", devpath, link_target);
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for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
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;
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dbg("base '%s', tail '%s', back %i\n", devpath, &link_target[back * 3], back);
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for (i = 0; i <= back; i++) {
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char *pos = strrchr(devpath, '/');
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if (pos == NULL)
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return -1;
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pos[0] = '\0';
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}
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dbg("after moving back '%s'\n", devpath);
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strlcat(devpath, "/", size);
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strlcat(devpath, &link_target[back * 3], size);
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return 0;
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}
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struct sysfs_device *sysfs_device_get(const char *devpath)
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{
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char path[PATH_SIZE];
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char devpath_real[PATH_SIZE];
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struct sysfs_device *dev;
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struct sysfs_device *dev_loop;
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struct stat statbuf;
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char link_path[PATH_SIZE];
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char link_target[PATH_SIZE];
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int len;
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char *pos;
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/* we handle only these devpathes */
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if (devpath != NULL &&
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strncmp(devpath, "/devices/", 9) != 0 &&
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strncmp(devpath, "/subsystem/", 11) != 0 &&
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strncmp(devpath, "/module/", 8) != 0 &&
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strncmp(devpath, "/bus/", 5) != 0 &&
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strncmp(devpath, "/class/", 7) != 0 &&
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strncmp(devpath, "/block/", 7) != 0)
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return NULL;
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dbg("open '%s'\n", devpath);
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strlcpy(devpath_real, devpath, sizeof(devpath_real));
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remove_trailing_chars(devpath_real, '/');
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if (devpath[0] == '\0' )
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return NULL;
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/* look for device already in cache (we never put an untranslated path in the cache) */
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list_for_each_entry(dev_loop, &dev_list, node) {
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if (strcmp(dev_loop->devpath, devpath_real) == 0) {
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dbg("found in cache '%s'\n", dev_loop->devpath);
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return dev_loop;
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}
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}
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/* if we got a link, resolve it to the real device */
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strlcpy(path, sysfs_path, sizeof(path));
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strlcat(path, devpath_real, sizeof(path));
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if (lstat(path, &statbuf) != 0) {
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dbg("stat '%s' failed: %s\n", path, strerror(errno));
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return NULL;
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}
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if (S_ISLNK(statbuf.st_mode)) {
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if (sysfs_resolve_link(devpath_real, sizeof(devpath_real)) != 0)
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return NULL;
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/* now look for device in cache after path translation */
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list_for_each_entry(dev_loop, &dev_list, node) {
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if (strcmp(dev_loop->devpath, devpath_real) == 0) {
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dbg("found in cache '%s'\n", dev_loop->devpath);
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return dev_loop;
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}
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}
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}
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/* it is a new device */
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dbg("new uncached device '%s'\n", devpath_real);
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dev = malloc(sizeof(struct sysfs_device));
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if (dev == NULL)
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return NULL;
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memset(dev, 0x00, sizeof(struct sysfs_device));
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sysfs_device_set_values(dev, devpath_real, NULL, NULL);
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/* get subsystem name */
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strlcpy(link_path, sysfs_path, sizeof(link_path));
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strlcat(link_path, dev->devpath, sizeof(link_path));
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strlcat(link_path, "/subsystem", sizeof(link_path));
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len = readlink(link_path, link_target, sizeof(link_target));
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if (len > 0) {
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/* get subsystem from "subsystem" link */
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link_target[len] = '\0';
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dbg("subsystem link '%s' points to '%s'\n", link_path, link_target);
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pos = strrchr(link_target, '/');
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if (pos != NULL)
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strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
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} else if (strstr(dev->devpath, "/drivers/") != NULL) {
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strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
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} else if (strncmp(dev->devpath, "/module/", 8) == 0) {
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strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
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} else if (strncmp(dev->devpath, "/subsystem/", 11) == 0) {
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pos = strrchr(dev->devpath, '/');
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if (pos == &dev->devpath[10])
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strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem));
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} else if (strncmp(dev->devpath, "/class/", 7) == 0) {
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pos = strrchr(dev->devpath, '/');
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if (pos == &dev->devpath[6])
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strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem));
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} else if (strncmp(dev->devpath, "/bus/", 5) == 0) {
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pos = strrchr(dev->devpath, '/');
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if (pos == &dev->devpath[4])
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strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem));
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}
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/* get driver name */
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strlcpy(link_path, sysfs_path, sizeof(link_path));
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strlcat(link_path, dev->devpath, sizeof(link_path));
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strlcat(link_path, "/driver", sizeof(link_path));
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len = readlink(link_path, link_target, sizeof(link_target));
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if (len > 0) {
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link_target[len] = '\0';
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dbg("driver link '%s' points to '%s'\n", link_path, link_target);
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pos = strrchr(link_target, '/');
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if (pos != NULL)
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strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
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}
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dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'\n", dev->devpath, dev->subsystem, dev->driver);
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list_add(&dev->node, &dev_list);
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return dev;
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}
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struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
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{
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char parent_devpath[PATH_SIZE];
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char *pos;
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dbg("open '%s'\n", dev->devpath);
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/* look if we already know the parent */
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if (dev->parent != NULL)
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return dev->parent;
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strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
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dbg("'%s'\n", parent_devpath);
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/* strip last element */
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pos = strrchr(parent_devpath, '/');
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if (pos == NULL || pos == parent_devpath)
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return NULL;
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pos[0] = '\0';
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if (strncmp(parent_devpath, "/class", 6) == 0) {
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pos = strrchr(parent_devpath, '/');
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if (pos == &parent_devpath[6] || pos == parent_devpath) {
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dbg("/class top level, look for device link\n");
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goto device_link;
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}
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}
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if (strcmp(parent_devpath, "/block") == 0) {
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dbg("/block top level, look for device link\n");
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goto device_link;
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}
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/* are we at the top level? */
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pos = strrchr(parent_devpath, '/');
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if (pos == NULL || pos == parent_devpath)
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return NULL;
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/* get parent and remember it */
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dev->parent = sysfs_device_get(parent_devpath);
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return dev->parent;
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device_link:
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strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
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strlcat(parent_devpath, "/device", sizeof(parent_devpath));
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if (sysfs_resolve_link(parent_devpath, sizeof(parent_devpath)) != 0)
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return NULL;
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/* get parent and remember it */
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dev->parent = sysfs_device_get(parent_devpath);
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return dev->parent;
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}
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struct sysfs_device *sysfs_device_get_parent_with_subsystem(struct sysfs_device *dev, const char *subsystem)
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{
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struct sysfs_device *dev_parent;
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dev_parent = sysfs_device_get_parent(dev);
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while (dev_parent != NULL) {
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if (strcmp(dev_parent->subsystem, subsystem) == 0)
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return dev_parent;
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dev_parent = sysfs_device_get_parent(dev_parent);
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}
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return NULL;
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}
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char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
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{
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char path_full[PATH_SIZE];
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const char *path;
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char value[NAME_SIZE];
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struct sysfs_attr *attr_loop;
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struct sysfs_attr *attr;
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struct stat statbuf;
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int fd;
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ssize_t size;
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size_t sysfs_len;
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dbg("open '%s'/'%s'\n", devpath, attr_name);
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sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
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if(sysfs_len >= sizeof(path_full))
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sysfs_len = sizeof(path_full) - 1;
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path = &path_full[sysfs_len];
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strlcat(path_full, devpath, sizeof(path_full));
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strlcat(path_full, "/", sizeof(path_full));
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strlcat(path_full, attr_name, sizeof(path_full));
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/* look for attribute in cache */
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list_for_each_entry(attr_loop, &attr_list, node) {
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if (strcmp(attr_loop->path, path) == 0) {
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dbg("found in cache '%s'\n", attr_loop->path);
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return attr_loop->value;
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}
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}
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/* store attribute in cache (also negatives are kept in cache) */
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dbg("new uncached attribute '%s'\n", path_full);
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attr = malloc(sizeof(struct sysfs_attr));
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if (attr == NULL)
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return NULL;
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memset(attr, 0x00, sizeof(struct sysfs_attr));
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strlcpy(attr->path, path, sizeof(attr->path));
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dbg("add to cache '%s'\n", path_full);
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list_add(&attr->node, &attr_list);
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if (lstat(path_full, &statbuf) != 0) {
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dbg("stat '%s' failed: %s\n", path_full, strerror(errno));
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goto out;
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}
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if (S_ISLNK(statbuf.st_mode)) {
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/* links return the last element of the target path */
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char link_target[PATH_SIZE];
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int len;
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const char *pos;
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len = readlink(path_full, link_target, sizeof(link_target));
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if (len > 0) {
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link_target[len] = '\0';
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pos = strrchr(link_target, '/');
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if (pos != NULL) {
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dbg("cache '%s' with link value '%s'\n", path_full, value);
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strlcpy(attr->value_local, &pos[1], sizeof(attr->value_local));
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attr->value = attr->value_local;
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}
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}
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goto out;
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}
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/* skip directories */
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if (S_ISDIR(statbuf.st_mode))
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goto out;
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/* skip non-readable files */
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if ((statbuf.st_mode & S_IRUSR) == 0)
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goto out;
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/* read attribute value */
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fd = open(path_full, O_RDONLY);
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if (fd < 0) {
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dbg("attribute '%s' can not be opened\n", path_full);
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goto out;
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}
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size = read(fd, value, sizeof(value));
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close(fd);
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if (size < 0)
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goto out;
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if (size == sizeof(value))
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goto out;
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/* got a valid value, store and return it */
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value[size] = '\0';
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remove_trailing_chars(value, '\n');
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dbg("cache '%s' with attribute value '%s'\n", path_full, value);
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strlcpy(attr->value_local, value, sizeof(attr->value_local));
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attr->value = attr->value_local;
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out:
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return attr->value;
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}
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int sysfs_lookup_devpath_by_subsys_id(char *devpath_full, size_t len, const char *subsystem, const char *id)
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{
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size_t sysfs_len;
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char path_full[PATH_SIZE];
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char *path;
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struct stat statbuf;
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sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
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path = &path_full[sysfs_len];
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if (strcmp(subsystem, "subsystem") == 0) {
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strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
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strlcat(path, id, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
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goto found;
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strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
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strlcat(path, id, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
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goto found;
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goto out;
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strlcpy(path, "/class/", sizeof(path_full) - sysfs_len);
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strlcat(path, id, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
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goto found;
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}
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if (strcmp(subsystem, "module") == 0) {
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strlcpy(path, "/module/", sizeof(path_full) - sysfs_len);
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strlcat(path, id, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
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goto found;
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goto out;
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}
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if (strcmp(subsystem, "drivers") == 0) {
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char subsys[NAME_SIZE];
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char *driver;
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strlcpy(subsys, id, sizeof(subsys));
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driver = strchr(subsys, ':');
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if (driver != NULL) {
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driver[0] = '\0';
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driver = &driver[1];
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strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
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strlcat(path, subsys, sizeof(path_full) - sysfs_len);
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strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
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strlcat(path, driver, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
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goto found;
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strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
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strlcat(path, subsys, sizeof(path_full) - sysfs_len);
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strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
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strlcat(path, driver, sizeof(path_full) - sysfs_len);
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if (stat(path_full, &statbuf) == 0)
|
|
goto found;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
|
|
strlcat(path, "/devices/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, id, sizeof(path_full) - sysfs_len);
|
|
if (stat(path_full, &statbuf) == 0)
|
|
goto found;
|
|
|
|
strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
|
|
strlcat(path, "/devices/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, id, sizeof(path_full) - sysfs_len);
|
|
if (stat(path_full, &statbuf) == 0)
|
|
goto found;
|
|
|
|
strlcpy(path, "/class/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
|
|
strlcat(path, "/", sizeof(path_full) - sysfs_len);
|
|
strlcat(path, id, sizeof(path_full) - sysfs_len);
|
|
if (stat(path_full, &statbuf) == 0)
|
|
goto found;
|
|
out:
|
|
return 0;
|
|
found:
|
|
if (S_ISLNK(statbuf.st_mode))
|
|
sysfs_resolve_link(path, sizeof(path_full) - sysfs_len);
|
|
strlcpy(devpath_full, path, len);
|
|
return 1;
|
|
}
|