summaryrefslogtreecommitdiff
path: root/udev_sysfs.c
diff options
context:
space:
mode:
authorKay Sievers <kay.sievers@suse.de>2006-01-09 21:18:00 +0100
committerKay Sievers <kay.sievers@suse.de>2006-01-09 21:18:00 +0100
commit1aa1e24848903d11780db1ade355be73ad61a937 (patch)
treefb15c937a1a6e9f0197c905cc7af6ee5df8b108c /udev_sysfs.c
parent47fbf3c58260e3fed1078061f8d45e01b0e120f0 (diff)
replace libsysfs
We never used any of the libsysfs convenience features. Here we replace it completely with 300 lines of code, which are much simpler and a bit faster cause udev(d) does not open any syfs file for a simple event which does not need any parent device information. Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Diffstat (limited to 'udev_sysfs.c')
-rw-r--r--udev_sysfs.c345
1 files changed, 345 insertions, 0 deletions
diff --git a/udev_sysfs.c b/udev_sysfs.c
new file mode 100644
index 0000000000..19fd614e63
--- /dev/null
+++ b/udev_sysfs.c
@@ -0,0 +1,345 @@
+/*
+ * udev_sysfs.c - sysfs access
+ *
+ * Copyright (C) 2005 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 version 2 of the License.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "udev.h"
+
+char sysfs_path[PATH_SIZE];
+
+/* device cache */
+static LIST_HEAD(dev_list);
+
+/* attribute value cache */
+static LIST_HEAD(attr_list);
+struct sysfs_attr {
+ struct list_head node;
+ char path[PATH_SIZE];
+ char value[NAME_SIZE];
+};
+
+int sysfs_init(void)
+{
+ const char *env;
+
+ env = getenv("SYSFS_PATH");
+ if (env) {
+ strlcpy(sysfs_path, env, sizeof(sysfs_path));
+ remove_trailing_chars(sysfs_path, '/');
+ } else
+ strlcpy(sysfs_path, "/sys", sizeof(sysfs_path));
+ dbg("sysfs_path='%s'", sysfs_path);
+
+ INIT_LIST_HEAD(&dev_list);
+ INIT_LIST_HEAD(&attr_list);
+ return 0;
+}
+
+void sysfs_cleanup(void)
+{
+ struct sysfs_attr *attr_loop;
+ struct sysfs_attr *attr_temp;
+ struct sysfs_device *dev_loop;
+ struct sysfs_device *dev_temp;
+
+ list_for_each_entry_safe(attr_loop, attr_temp, &attr_list, node) {
+ list_del(&attr_loop->node);
+ free(attr_loop);
+ }
+
+ list_for_each_entry_safe(dev_loop, dev_temp, &dev_list, node) {
+ list_del(&dev_loop->node);
+ free(dev_loop);
+ }
+}
+
+void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath, const char *subsystem)
+{
+ char *pos;
+
+ strlcpy(dev->devpath, devpath, sizeof(dev->devpath));
+ if (subsystem != NULL)
+ strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem));
+
+ /* set kernel name */
+ pos = strrchr(dev->devpath, '/');
+ if (pos == NULL)
+ return;
+
+ strlcpy(dev->kernel_name, &pos[1], sizeof(dev->kernel_name));
+ dbg("kernel_name='%s'", dev->kernel_name);
+
+ /* some devices have '!' in their name, change that to '/' */
+ pos = dev->kernel_name;
+ while (pos[0] != '\0') {
+ if (pos[0] == '!')
+ pos[0] = '/';
+ pos++;
+ }
+
+ /* get kernel number */
+ pos = &dev->kernel_name[strlen(dev->kernel_name)];
+ while (isdigit(pos[-1]))
+ pos--;
+ strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number));
+ dbg("kernel_number='%s'", dev->kernel_number);
+}
+
+struct sysfs_device *sysfs_device_get(const char *devpath)
+{
+ char path[PATH_SIZE];
+ char devpath_real[PATH_SIZE];
+ struct sysfs_device *dev;
+ struct sysfs_device *dev_loop;
+ struct stat statbuf;
+ char link_path[PATH_SIZE];
+ char link_target[PATH_SIZE];
+ int len;
+ char *pos;
+
+ dbg("open '%s'", devpath);
+ strlcpy(devpath_real, devpath, sizeof(devpath_real));
+ remove_trailing_chars(devpath_real, '/');
+
+ strlcpy(path, sysfs_path, sizeof(path));
+ strlcat(path, devpath_real, sizeof(path));
+ if (lstat(path, &statbuf) != 0) {
+ dbg("stat '%s' failed: %s", devpath, strerror(errno));
+ return NULL;
+ }
+
+ /* if we got a link, resolve it to the real device */
+ if (S_ISLNK(statbuf.st_mode)) {
+ int i;
+ int back;
+
+ len = readlink(path, link_target, sizeof(link_target));
+ if (len <= 0)
+ return NULL;
+ link_target[len] = '\0';
+ dbg("devpath link '%s' points to '%s'", path, link_target);
+
+ for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
+ ;
+ dbg("base '%s', tail '%s', back %i", devpath_real, &link_target[back * 3], back);
+ for (i = 0; i <= back; i++) {
+ pos = strrchr(devpath_real, '/');
+ if (pos == NULL)
+ return NULL;
+ pos[0] = '\0';
+ }
+ dbg("after moving back '%s'", devpath_real);
+ strlcat(devpath_real, "/", sizeof(devpath_real));
+ strlcat(devpath_real, &link_target[back * 3], sizeof(devpath_real));
+ }
+
+ /* look for device in cache */
+ list_for_each_entry(dev_loop, &dev_list, node) {
+ if (strcmp(dev_loop->devpath, devpath_real) == 0) {
+ dbg("found in cache '%s'", dev_loop->devpath);
+ return dev_loop;
+ }
+ }
+
+ /* new device */
+ dbg("'%s'", devpath_real);
+ dev = malloc(sizeof(struct sysfs_device));
+ if (dev == NULL)
+ return NULL;
+ memset(dev, 0x00, sizeof(struct sysfs_device));
+
+ sysfs_device_set_values(dev, devpath_real, NULL);
+
+ /* get subsystem */
+ if (strncmp(dev->devpath, "/class/", 7) == 0) {
+ strlcpy(dev->subsystem, &dev->devpath[7], sizeof(dev->subsystem));
+ pos = strchr(dev->subsystem, '/');
+ if (pos != NULL)
+ pos[0] = '\0';
+ else
+ dev->subsystem[0] = '\0';
+ } else if (strncmp(devpath, "/block/", 7) == 0) {
+ strlcpy(dev->subsystem, "block", sizeof(dev->subsystem));
+ } else if (strncmp(devpath, "/devices/", 9) == 0) {
+ /* get subsystem from bus name */
+ strlcpy(link_path, sysfs_path, sizeof(link_path));
+ strlcat(link_path, dev->devpath, sizeof(link_path));
+ strlcat(link_path, "/bus", sizeof(link_path));
+ len = readlink(link_path, link_target, sizeof(link_target));
+ if (len > 0) {
+ link_target[len] = '\0';
+ dbg("bus link '%s' points to '%s'", link_path, link_target);
+ pos = strrchr(link_target, '/');
+ if (pos != NULL)
+ strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
+ }
+
+ /* get driver name */
+ strlcpy(link_path, sysfs_path, sizeof(link_path));
+ strlcat(link_path, dev->devpath, sizeof(link_path));
+ strlcat(link_path, "/driver", sizeof(link_path));
+ len = readlink(link_path, link_target, sizeof(link_target));
+ if (len > 0) {
+ link_target[len] = '\0';
+ dbg("driver link '%s' points to '%s'", link_path, link_target);
+ pos = strrchr(link_target, '/');
+ if (pos != NULL)
+ strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
+ }
+ } else if (strncmp(devpath, "/bus/", 5) == 0 && strstr(devpath, "/drivers/")) {
+ strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
+ } else if (strncmp(devpath, "/module/", 8) == 0) {
+ strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
+ }
+
+ dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'", dev->devpath, dev->subsystem, dev->driver);
+ list_add(&dev->node, &dev_list);
+
+ return dev;
+}
+
+struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
+{
+ char parent_devpath[PATH_SIZE];
+ char device_link[PATH_SIZE];
+ char device_link_target[PATH_SIZE];
+ char *pos;
+ int i;
+ int len;
+ int back;
+
+ /* requesting a parent is only valid for devices */
+ if ((strncmp(dev->devpath, "/devices/", 9) != 0) &&
+ (strncmp(dev->devpath, "/class/", 7) != 0) &&
+ (strncmp(dev->devpath, "/block/", 7) != 0))
+ return NULL;
+
+ strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
+ dbg("'%s'", parent_devpath);
+
+ /* strip last element */
+ pos = strrchr(parent_devpath, '/');
+ if (pos == NULL || pos == parent_devpath)
+ return NULL;
+ pos[0] = '\0';
+
+ /* are we at the top level */
+ if (strcmp(parent_devpath, "/devices") == 0) {
+ dbg("/devices top level");
+ return NULL;
+ }
+
+ /* at the top level we may follow the "device" link */
+ if (strcmp(parent_devpath, "/block") == 0) {
+ dbg("/block top level, look for device link");
+ goto device_link;
+ }
+
+ if (strncmp(parent_devpath, "/class", 6) == 0) {
+ pos = strrchr(parent_devpath, '/');
+ if (pos == &parent_devpath[6] || pos == parent_devpath) {
+ dbg("class top level, look for device link");
+ goto device_link;
+ }
+ }
+ return sysfs_device_get(parent_devpath);
+
+device_link:
+ strlcpy(device_link, sysfs_path, sizeof(device_link));
+ strlcat(device_link, dev->devpath, sizeof(device_link));
+ strlcat(device_link, "/device", sizeof(device_link));
+ len = readlink(device_link, device_link_target, sizeof(device_link_target));
+ if (len < 0)
+ return NULL;
+ device_link_target[len] = '\0';
+ dbg("device link '%s' points to '%s'", device_link, device_link_target);
+
+ for (back = 0; strncmp(&device_link_target[back * 3], "../", 3) == 0; back++)
+ ;
+ strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
+ dbg("base='%s', tail='%s', back=%i", parent_devpath, &device_link_target[back * 3], back);
+ for (i = 0; i < back; i++) {
+ pos = strrchr(parent_devpath, '/');
+ if (pos == NULL)
+ return NULL;
+ pos[0] = '\0';
+ }
+ dbg("after moving back '%s'", parent_devpath);
+ strlcat(parent_devpath, "/", sizeof(parent_devpath));
+ strlcat(parent_devpath, &device_link_target[back * 3], sizeof(parent_devpath));
+ return sysfs_device_get(parent_devpath);
+}
+
+char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
+{
+ char path_full[PATH_SIZE];
+ const char *path;
+ char value[NAME_SIZE];
+ struct sysfs_attr *attr_loop;
+ struct sysfs_attr *attr;
+ int fd;
+ ssize_t size;
+ size_t sysfs_len;
+
+ sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
+ path = &path_full[sysfs_len];
+ strlcat(path_full, devpath, sizeof(path_full));
+ strlcat(path_full, "/", sizeof(path_full));
+ strlcat(path_full, attr_name, sizeof(path_full));
+
+ /* look for attribute in cache */
+ list_for_each_entry(attr_loop, &attr_list, node) {
+ if (strcmp(attr_loop->path, path) == 0) {
+ dbg("found in cache '%s'", attr_loop->path);
+ return attr_loop->value;
+ }
+ }
+
+ /* read attribute value */
+ fd = open(path_full, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+ size = read(fd, value, sizeof(value));
+ close(fd);
+ if (size < 0)
+ return NULL;
+ if (size == sizeof(value))
+ return NULL;
+ value[size] = '\0';
+ remove_trailing_chars(value, '\n');
+
+ /* store attribute in cache */
+ attr = malloc(sizeof(struct sysfs_attr));
+ if (attr == NULL)
+ return NULL;
+ strlcpy(attr->path, path, sizeof(attr->path));
+ strlcpy(attr->value, value, sizeof(attr->value));
+ dbg("add to cache '%s' '%s'", attr->path, attr->value);
+ list_add(&attr->node, &attr_list);
+
+ return attr->value;
+}