|
Packit |
229ac0 |
/*
|
|
Packit |
229ac0 |
* Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org>
|
|
Packit |
229ac0 |
* 2008 Jaroslav Kysela <perex@perex.cz>
|
|
Packit |
229ac0 |
*
|
|
Packit |
229ac0 |
* This program is free software; you can redistribute it and/or modify it
|
|
Packit |
229ac0 |
* under the terms of the GNU General Public License as published by the
|
|
Packit |
229ac0 |
* Free Software Foundation version 2 of the License.
|
|
Packit |
229ac0 |
*
|
|
Packit |
229ac0 |
* This program is distributed in the hope that it will be useful, but
|
|
Packit |
229ac0 |
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
Packit |
229ac0 |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Packit |
229ac0 |
* General Public License for more details.
|
|
Packit |
229ac0 |
*
|
|
Packit |
229ac0 |
* You should have received a copy of the GNU General Public License along
|
|
Packit |
229ac0 |
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
Packit |
229ac0 |
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
Packit |
229ac0 |
*
|
|
Packit |
229ac0 |
*/
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
static char sysfs_path[PATH_SIZE];
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* attribute value cache */
|
|
Packit |
229ac0 |
static LIST_HEAD(attr_list);
|
|
Packit |
229ac0 |
struct sysfs_attr {
|
|
Packit |
229ac0 |
struct list_head node;
|
|
Packit |
229ac0 |
char path[PATH_SIZE];
|
|
Packit |
229ac0 |
char *value; /* points to value_local if value is cached */
|
|
Packit |
229ac0 |
char value_local[NAME_SIZE];
|
|
Packit |
229ac0 |
};
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
static int sysfs_init(void)
|
|
Packit |
229ac0 |
{
|
|
Packit |
229ac0 |
const char *env;
|
|
Packit |
229ac0 |
char sysfs_test[PATH_SIZE];
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
env = getenv("SYSFS_PATH");
|
|
Packit |
229ac0 |
if (env) {
|
|
Packit |
229ac0 |
strlcpy(sysfs_path, env, sizeof(sysfs_path));
|
|
Packit |
229ac0 |
remove_trailing_chars(sysfs_path, '/');
|
|
Packit |
229ac0 |
} else
|
|
Packit |
229ac0 |
strlcpy(sysfs_path, "/sys", sizeof(sysfs_path));
|
|
Packit |
229ac0 |
dbg("sysfs_path='%s'", sysfs_path);
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
strlcpy(sysfs_test, sysfs_path, sizeof(sysfs_test));
|
|
Packit |
229ac0 |
strlcat(sysfs_test, "/kernel/uevent_helper", sizeof(sysfs_test));
|
|
Packit |
229ac0 |
if (access(sysfs_test, F_OK)) {
|
|
Packit |
229ac0 |
error("sysfs path '%s' is invalid\n", sysfs_path);
|
|
Packit |
229ac0 |
return -errno;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
INIT_LIST_HEAD(&attr_list);
|
|
Packit |
229ac0 |
return 0;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
static void sysfs_cleanup(void)
|
|
Packit |
229ac0 |
{
|
|
Packit |
229ac0 |
struct sysfs_attr *attr_loop;
|
|
Packit |
229ac0 |
struct sysfs_attr *attr_temp;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
list_for_each_entry_safe(attr_loop, attr_temp, &attr_list, node) {
|
|
Packit |
229ac0 |
list_del(&attr_loop->node);
|
|
Packit |
229ac0 |
free(attr_loop);
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
static char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
|
|
Packit |
229ac0 |
{
|
|
Packit |
229ac0 |
char path_full[PATH_SIZE];
|
|
Packit |
229ac0 |
const char *path;
|
|
Packit |
229ac0 |
char value[NAME_SIZE];
|
|
Packit |
229ac0 |
struct sysfs_attr *attr_loop;
|
|
Packit |
229ac0 |
struct sysfs_attr *attr;
|
|
Packit |
229ac0 |
struct stat statbuf;
|
|
Packit |
229ac0 |
int fd;
|
|
Packit |
229ac0 |
ssize_t size;
|
|
Packit |
229ac0 |
size_t sysfs_len;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
dbg("open '%s'/'%s'", devpath, attr_name);
|
|
Packit |
229ac0 |
sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
|
|
Packit |
229ac0 |
path = &path_full[sysfs_len];
|
|
Packit |
229ac0 |
strlcat(path_full, devpath, sizeof(path_full));
|
|
Packit |
229ac0 |
strlcat(path_full, "/", sizeof(path_full));
|
|
Packit |
229ac0 |
strlcat(path_full, attr_name, sizeof(path_full));
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* look for attribute in cache */
|
|
Packit |
229ac0 |
list_for_each_entry(attr_loop, &attr_list, node) {
|
|
Packit |
229ac0 |
if (strcmp(attr_loop->path, path) == 0) {
|
|
Packit |
229ac0 |
dbg("found in cache '%s'", attr_loop->path);
|
|
Packit |
229ac0 |
return attr_loop->value;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* store attribute in cache (also negatives are kept in cache) */
|
|
Packit |
229ac0 |
dbg("new uncached attribute '%s'", path_full);
|
|
Packit |
229ac0 |
attr = malloc(sizeof(struct sysfs_attr));
|
|
Packit |
229ac0 |
if (attr == NULL)
|
|
Packit |
229ac0 |
return NULL;
|
|
Packit |
229ac0 |
memset(attr, 0x00, sizeof(struct sysfs_attr));
|
|
Packit |
229ac0 |
strlcpy(attr->path, path, sizeof(attr->path));
|
|
Packit |
229ac0 |
dbg("add to cache '%s'", path_full);
|
|
Packit |
229ac0 |
list_add(&attr->node, &attr_list);
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
if (lstat(path_full, &statbuf) != 0) {
|
|
Packit |
229ac0 |
dbg("stat '%s' failed: %s", path_full, strerror(errno));
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
if (S_ISLNK(statbuf.st_mode)) {
|
|
Packit |
229ac0 |
/* links return the last element of the target path */
|
|
Packit |
229ac0 |
char link_target[PATH_SIZE + 1];
|
|
Packit |
229ac0 |
int len;
|
|
Packit |
229ac0 |
const char *pos;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
len = readlink(path_full, link_target, sizeof(link_target) - 1);
|
|
Packit |
229ac0 |
if (len > 0) {
|
|
Packit |
229ac0 |
link_target[len] = '\0';
|
|
Packit |
229ac0 |
pos = strrchr(link_target, '/');
|
|
Packit |
229ac0 |
if (pos != NULL) {
|
|
Packit |
229ac0 |
dbg("cache '%s' with link value '%s'", path_full, pos+1);
|
|
Packit |
229ac0 |
strlcpy(attr->value_local, &pos[1], sizeof(attr->value_local));
|
|
Packit |
229ac0 |
attr->value = attr->value_local;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* skip directories */
|
|
Packit |
229ac0 |
if (S_ISDIR(statbuf.st_mode))
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* skip non-readable files */
|
|
Packit |
229ac0 |
if ((statbuf.st_mode & S_IRUSR) == 0)
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* read attribute value */
|
|
Packit |
229ac0 |
fd = open(path_full, O_RDONLY);
|
|
Packit |
229ac0 |
if (fd < 0) {
|
|
Packit |
229ac0 |
dbg("attribute '%s' does not exist", path_full);
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
}
|
|
Packit |
229ac0 |
size = read(fd, value, sizeof(value));
|
|
Packit |
229ac0 |
close(fd);
|
|
Packit |
229ac0 |
if (size < 0)
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
if (size == sizeof(value))
|
|
Packit |
229ac0 |
goto out;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
/* got a valid value, store and return it */
|
|
Packit |
229ac0 |
value[size] = '\0';
|
|
Packit |
229ac0 |
remove_trailing_chars(value, '\n');
|
|
Packit |
229ac0 |
dbg("cache '%s' with attribute value '%s'", path_full, value);
|
|
Packit |
229ac0 |
strlcpy(attr->value_local, value, sizeof(attr->value_local));
|
|
Packit |
229ac0 |
attr->value = attr->value_local;
|
|
Packit |
229ac0 |
|
|
Packit |
229ac0 |
out:
|
|
Packit |
229ac0 |
return attr->value;
|
|
Packit |
229ac0 |
}
|