/*
* This is from udev-121's udev_sysfs.c
*
* Copyright (C) 2005-2006 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <inttypes.h>
#include <sys/stat.h>
#include "log.h"
#include "sysdeps.h"
#include "sysfs.h"
/*
* We take this file from udev so we want to make as few changes are possible,
* so we can maintain patches.
*
* This is from udev_utils_string.c
*/
static void remove_trailing_chars(char *path, char c)
{
size_t len;
len = strlen(path);
while (len > 0 && path[len-1] == c)
path[--len] = '\0';
}
/* this converts udevs logging to ours. */
#define dbg(format, arg...) \
do { \
log_debug(3, "%s: " format, __FUNCTION__,## arg); \
} while (0)
/*
* Begin udev_sysfs.c code
*/
char sysfs_path[PATH_SIZE];
/* device cache */
static LIST_HEAD(dev_list);
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);
return 0;
}
void sysfs_cleanup(void)
{
struct sysfs_device *dev_loop;
struct sysfs_device *dev_temp;
list_for_each_entry_safe(dev_loop, dev_temp, &dev_list, node) {
list_del_init(&dev_loop->node);
free(dev_loop);
}
}
void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
const char *subsystem, const char *driver)
{
char *pos;
strlcpy(dev->devpath, devpath, sizeof(dev->devpath));
if (subsystem != NULL)
strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem));
if (driver != NULL)
strlcpy(dev->driver, driver, sizeof(dev->driver));
/* set kernel name */
pos = strrchr(dev->devpath, '/');
if (pos == NULL)
return;
strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel));
dbg("kernel='%s'", dev->kernel);
/* some devices have '!' in their name, change that to '/' */
pos = dev->kernel;
while (pos[0] != '\0') {
if (pos[0] == '!')
pos[0] = '/';
pos++;
}
/* get kernel number */
pos = &dev->kernel[strlen(dev->kernel)];
while (isdigit(pos[-1]))
pos--;
strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number));
dbg("kernel_number='%s'", dev->kernel_number);
}
int sysfs_resolve_link(char *devpath, size_t size)
{
char link_path[PATH_SIZE];
char link_target[PATH_SIZE];
int len;
int i;
int back;
strlcpy(link_path, sysfs_path, sizeof(link_path));
strlcat(link_path, devpath, sizeof(link_path));
len = readlink(link_path, link_target, sizeof(link_target) - 1);
if (len <= 0)
return -1;
link_target[len] = '\0';
dbg("path link '%s' points to '%s'", devpath, link_target);
for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
;
dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back);
for (i = 0; i <= back; i++) {
char *pos = strrchr(devpath, '/');
if (pos == NULL)
return -1;
pos[0] = '\0';
}
dbg("after moving back '%s'", devpath);
strlcat(devpath, "/", size);
strlcat(devpath, &link_target[back * 3], size);
return 0;
}
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;
/* we handle only these devpathes */
if (devpath != NULL &&
strncmp(devpath, "/devices/", 9) != 0 &&
strncmp(devpath, "/subsystem/", 11) != 0 &&
strncmp(devpath, "/module/", 8) != 0 &&
strncmp(devpath, "/bus/", 5) != 0 &&
strncmp(devpath, "/class/", 7) != 0 &&
strncmp(devpath, "/block/", 7) != 0)
return NULL;
dbg("open '%s'", devpath);
strlcpy(devpath_real, devpath, sizeof(devpath_real));
remove_trailing_chars(devpath_real, '/');
if (devpath[0] == '\0' )
return NULL;
/* look for device already in cache (we never put an untranslated path in the 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;
}
}
/* if we got a link, resolve it to the real device */
strlcpy(path, sysfs_path, sizeof(path));
strlcat(path, devpath_real, sizeof(path));
if (lstat(path, &statbuf) != 0) {
dbg("stat '%s' failed: %s", path, strerror(errno));
return NULL;
}
if (S_ISLNK(statbuf.st_mode)) {
if (sysfs_resolve_link(devpath_real, sizeof(devpath_real)) != 0)
return NULL;
/* now look for device in cache after path translation */
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;
}
}
}
/* it is a new device */
dbg("new uncached device '%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, NULL);
/* get subsystem name */
strlcpy(link_path, sysfs_path, sizeof(link_path));
strlcat(link_path, dev->devpath, sizeof(link_path));
strlcat(link_path, "/subsystem", sizeof(link_path));
len = readlink(link_path, link_target, sizeof(link_target) - 1);
if (len > 0) {
/* get subsystem from "subsystem" link */
link_target[len] = '\0';
dbg("subsystem link '%s' points to '%s'", link_path, link_target);
pos = strrchr(link_target, '/');
if (pos != NULL)
strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
} else if (strstr(dev->devpath, "/drivers/") != NULL) {
strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
} else if (strncmp(dev->devpath, "/module/", 8) == 0) {
strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
} else if (strncmp(dev->devpath, "/subsystem/", 11) == 0) {
pos = strrchr(dev->devpath, '/');
if (pos == &dev->devpath[10])
strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem));
} else if (strncmp(dev->devpath, "/class/", 7) == 0) {
pos = strrchr(dev->devpath, '/');
if (pos == &dev->devpath[6])
strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem));
} else if (strncmp(dev->devpath, "/bus/", 5) == 0) {
pos = strrchr(dev->devpath, '/');
if (pos == &dev->devpath[4])
strlcpy(dev->subsystem, "subsystem", 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) - 1);
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));
}
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 *pos;
dbg("open '%s'", dev->devpath);
/* look if we already know the parent */
if (dev->parent != NULL)
return dev->parent;
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';
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;
}
}
if (strcmp(parent_devpath, "/block") == 0) {
dbg("/block top level, look for device link");
goto device_link;
}
/* are we at the top level? */
pos = strrchr(parent_devpath, '/');
if (pos == NULL || pos == parent_devpath)
return NULL;
/* get parent and remember it */
dev->parent = sysfs_device_get(parent_devpath);
return dev->parent;
device_link:
strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
strlcat(parent_devpath, "/device", sizeof(parent_devpath));
if (sysfs_resolve_link(parent_devpath, sizeof(parent_devpath)) != 0)
return NULL;
/* get parent and remember it */
dev->parent = sysfs_device_get(parent_devpath);
return dev->parent;
}
struct sysfs_device *sysfs_device_get_parent_with_subsystem(struct sysfs_device *dev, const char *subsystem)
{
struct sysfs_device *dev_parent;
dev_parent = sysfs_device_get_parent(dev);
while (dev_parent != NULL) {
if (strcmp(dev_parent->subsystem, subsystem) == 0)
return dev_parent;
dev_parent = sysfs_device_get_parent(dev_parent);
}
return NULL;
}
char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
{
char path_full[PATH_SIZE];
char value[NAME_SIZE] = { '\0', };
struct stat statbuf;
int fd;
ssize_t size;
size_t sysfs_len;
dbg("open '%s'/'%s'", devpath, attr_name);
sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
if(sysfs_len >= sizeof(path_full))
sysfs_len = sizeof(path_full) - 1;
strlcat(path_full, devpath, sizeof(path_full));
strlcat(path_full, "/", sizeof(path_full));
strlcat(path_full, attr_name, sizeof(path_full));
if (lstat(path_full, &statbuf) != 0) {
dbg("stat '%s' failed: %s", path_full, strerror(errno));
goto out;
}
if (S_ISLNK(statbuf.st_mode)) {
/* links return the last element of the target path */
char link_target[PATH_SIZE];
int len;
const char *pos;
len = readlink(path_full, link_target, sizeof(link_target) - 1);
if (len > 0) {
link_target[len] = '\0';
pos = strrchr(link_target, '/');
if (pos != NULL) {
dbg("cache '%s' with link value '%s'", path_full, value);
strlcpy(value, &pos[1], NAME_SIZE);
}
}
goto out;
}
/* skip directories */
if (S_ISDIR(statbuf.st_mode))
goto out;
/* skip non-readable files */
if ((statbuf.st_mode & S_IRUSR) == 0)
goto out;
/* read attribute value */
fd = open(path_full, O_RDONLY);
if (fd < 0) {
dbg("attribute '%s' can not be opened", path_full);
goto out;
}
size = read(fd, value, sizeof(value));
close(fd);
if (size < 0)
goto out;
if (size == sizeof(value))
goto out;
/* got a valid value, store and return it */
value[size] = '\0';
remove_trailing_chars(value, '\n');
out:
if (value[0] == '\0')
return NULL;
return strdup(value);
}
int sysfs_lookup_devpath_by_subsys_id(char *devpath_full, size_t len, const char *subsystem, const char *id)
{
size_t sysfs_len;
char path_full[PATH_SIZE];
char *path;
struct stat statbuf;
sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
path = &path_full[sysfs_len];
if (strcmp(subsystem, "subsystem") == 0) {
strlcpy(path, "/subsystem/", 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, id, sizeof(path_full) - sysfs_len);
if (stat(path_full, &statbuf) == 0)
goto found;
goto out;
strlcpy(path, "/class/", sizeof(path_full) - sysfs_len);
strlcat(path, id, sizeof(path_full) - sysfs_len);
if (stat(path_full, &statbuf) == 0)
goto found;
}
if (strcmp(subsystem, "module") == 0) {
strlcpy(path, "/module/", sizeof(path_full) - sysfs_len);
strlcat(path, id, sizeof(path_full) - sysfs_len);
if (stat(path_full, &statbuf) == 0)
goto found;
goto out;
}
if (strcmp(subsystem, "drivers") == 0) {
char subsys[NAME_SIZE];
char *driver;
strlcpy(subsys, id, sizeof(subsys));
driver = strchr(subsys, ':');
if (driver != NULL) {
driver[0] = '\0';
driver = &driver[1];
strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
strlcat(path, subsys, sizeof(path_full) - sysfs_len);
strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
strlcat(path, driver, sizeof(path_full) - sysfs_len);
if (stat(path_full, &statbuf) == 0)
goto found;
strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
strlcat(path, subsys, sizeof(path_full) - sysfs_len);
strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
strlcat(path, driver, sizeof(path_full) - sysfs_len);
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;
strlcpy(path, "/firmware/", 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;
}
char *sysfs_get_value(const char *id, char *subsys, char *param)
{
char devpath[PATH_SIZE];
char *sysfs_value;
if (!sysfs_lookup_devpath_by_subsys_id(devpath, sizeof(devpath),
subsys, id)) {
log_debug(3, "Could not lookup devpath for %s %s",
subsys, id);
return NULL;
}
sysfs_value = sysfs_attr_get_value(devpath, param);
if (!sysfs_value) {
log_debug(3, "Could not read attr %s on path %s",
param, devpath);
return NULL;
}
if (!strncmp(sysfs_value, "<NULL>", 6) ||
!strncmp(sysfs_value, "(null)", 6)) {
free(sysfs_value);
return NULL;
}
return sysfs_value;
}
int sysfs_get_uint(char *id, char *subsys, char *param,
unsigned int *value)
{
char *sysfs_value;
*value = -1;
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value)
return EIO;
errno = 0;
*value = strtoul(sysfs_value, NULL, 0);
free(sysfs_value);
if (errno)
return errno;
return 0;
}
int sysfs_get_int(const char *id, char *subsys, char *param, int *value)
{
char *sysfs_value;
*value = -1;
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value)
return EIO;
*value = atoi(sysfs_value);
free(sysfs_value);
return 0;
}
int sysfs_get_str(char *id, char *subsys, char *param, char *value,
int value_size)
{
char *sysfs_value;
int len;
value[0] = '\0';
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value || !strlen(sysfs_value))
return EIO;
len = strlen(sysfs_value);
if (len && (sysfs_value[len - 1] == '\n'))
sysfs_value[len - 1] = '\0';
strncpy(value, sysfs_value, value_size);
value[value_size - 1] = '\0';
free(sysfs_value);
return 0;
}
int sysfs_get_uint64(char *id, char *subsys, char *param, uint64_t *value)
{
char *sysfs_value;
*value = -1;
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value)
return EIO;
if (sscanf(sysfs_value, "%" PRIu64 "\n", value) != 1) {
free(sysfs_value);
return EINVAL;
}
free(sysfs_value);
return 0;
}
int sysfs_get_uint8(char *id, char *subsys, char *param,
uint8_t *value)
{
char *sysfs_value;
*value = -1;
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value)
return EIO;
*value = (uint8_t)atoi(sysfs_value);
free(sysfs_value);
return 0;
}
int sysfs_get_uint16(char *id, char *subsys, char *param,
uint16_t *value)
{
char *sysfs_value;
*value = -1;
sysfs_value = sysfs_get_value(id, subsys, param);
if (!sysfs_value)
return EIO;
*value = (uint16_t)atoi(sysfs_value);
free(sysfs_value);
return 0;
}
int sysfs_set_param(char *id, char *subsys, char *attr_name,
char *write_buf, ssize_t buf_size)
{
struct stat statbuf;
char devpath[PATH_SIZE];
size_t sysfs_len;
char path_full[PATH_SIZE];
int rc = 0, fd;
if (!sysfs_lookup_devpath_by_subsys_id(devpath, sizeof(devpath),
subsys, id)) {
log_debug(3, "Could not lookup devpath for %s %s",
subsys, id);
return EIO;
}
sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
if(sysfs_len >= sizeof(path_full))
sysfs_len = sizeof(path_full) - 1;
strlcat(path_full, devpath, sizeof(path_full));
strlcat(path_full, "/", sizeof(path_full));
strlcat(path_full, attr_name, sizeof(path_full));
if (lstat(path_full, &statbuf)) {
log_debug(3, "Could not stat %s", path_full);
return errno;
}
if ((statbuf.st_mode & S_IWUSR) == 0) {
log_error("Could not write to %s. Invalid permissions.",
path_full);
return EACCES;
}
fd = open(path_full, O_WRONLY);
if (fd < 0) {
log_error("Could not open %s err %d", path_full, errno);
return errno;
}
if (write(fd, write_buf, buf_size) == -1)
rc = errno;
close(fd);
return rc;
}
char *sysfs_get_uevent_field(const char *path, const char *field)
{
char *uevent_path = NULL;
FILE *f = NULL;
char *line, buffer[1024];
char *ff, *d;
char *out = NULL;
uevent_path = calloc(1, PATH_MAX);
if (!uevent_path)
return NULL;
snprintf(uevent_path, PATH_MAX, "%s/uevent", path);
f = fopen(uevent_path, "r");
if (!f)
goto out;
while ((line = fgets(buffer, sizeof (buffer), f))) {
ff = strtok(line, "=");
d = strtok(NULL, "\n");
if (strcmp(ff, field))
continue;
out = strdup(d);
break;
}
fclose(f);
out:
free(uevent_path);
return out;
}
char *sysfs_get_uevent_devtype(const char *path)
{
return sysfs_get_uevent_field(path, "DEVTYPE");
}
char *sysfs_get_uevent_devname(const char *path)
{
return sysfs_get_uevent_field(path, "DEVNAME");
}