udev_rules.c revision 98bbc835f584ed6792e895519326cc637f64f411
/*
* udev_rules.c
*
* Userspace devfs
*
* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2003-2005 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 <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <ctype.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include "libsysfs/sysfs/libsysfs.h"
#include "list.h"
#include "udev_libc_wrapper.h"
#include "udev.h"
#include "udev_utils.h"
#include "udev_version.h"
#include "logging.h"
#include "udev_rules.h"
#include "udev_db.h"
/* compare string with pattern (supports * ? [0-9] [!A-Z]) */
static int strcmp_pattern(const char *p, const char *s)
{
if (s[0] == '\0') {
while (p[0] == '*')
p++;
return (p[0] != '\0');
}
switch (p[0]) {
case '[':
{
int not = 0;
p++;
if (p[0] == '!') {
not = 1;
p++;
}
while ((p[0] != '\0') && (p[0] != ']')) {
int match = 0;
if (p[1] == '-') {
if ((s[0] >= p[0]) && (s[0] <= p[2]))
match = 1;
p += 3;
} else {
match = (p[0] == s[0]);
p++;
}
if (match ^ not) {
while ((p[0] != '\0') && (p[0] != ']'))
p++;
if (p[0] == ']')
return strcmp_pattern(p+1, s+1);
}
}
}
break;
case '*':
if (strcmp_pattern(p, s+1))
return strcmp_pattern(p+1, s);
return 0;
case '\0':
if (s[0] == '\0') {
return 0;
}
break;
default:
if ((p[0] == s[0]) || (p[0] == '?'))
return strcmp_pattern(p+1, s+1);
break;
}
return 1;
}
/* extract possible {attr} and move str behind it */
static char *get_format_attribute(char **str)
{
char *pos;
char *attr = NULL;
if (*str[0] == '{') {
pos = strchr(*str, '}');
if (pos == NULL) {
err("missing closing brace for format");
return NULL;
}
pos[0] = '\0';
attr = *str+1;
*str = pos+1;
dbg("attribute='%s', str='%s'", attr, *str);
}
return attr;
}
/* extract possible format length and move str behind it*/
static int get_format_len(char **str)
{
int num;
char *tail;
if (isdigit(*str[0])) {
num = (int) strtoul(*str, &tail, 10);
if (num > 0) {
*str = tail;
dbg("format length=%i", num);
return num;
} else {
err("format parsing error '%s'", *str);
}
}
return -1;
}
/** Finds the lowest positive N such that <name>N isn't present in
* $(udevroot) either as a file or a symlink.
*
* @param name Name to check for
* @return 0 if <name> didn't exist and N otherwise.
*/
static int find_free_number(struct udevice *udev, const char *name)
{
char devpath[PATH_SIZE];
char filename[PATH_SIZE];
int num = 0;
strlcpy(filename, name, sizeof(filename));
while (1) {
dbg("look for existing node '%s'", filename);
if (udev_db_search_name(devpath, sizeof(devpath), filename) != 0) {
dbg("free num=%d", num);
return num;
}
num++;
if (num > 1000) {
info("find_free_number gone crazy (num=%d), aborted", num);
return -1;
}
snprintf(filename, sizeof(filename), "%s%d", name, num);
filename[sizeof(filename)-1] = '\0';
}
}
static int find_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device,
const char *name, char *value, size_t len)
{
struct sysfs_attribute *tmpattr;
dbg("look for device attribute '%s'", name);
if (class_dev) {
tmpattr = sysfs_get_classdev_attr(class_dev, name);
if (tmpattr)
goto attr_found;
}
if (sysfs_device) {
tmpattr = sysfs_get_device_attr(sysfs_device, name);
if (tmpattr)
goto attr_found;
}
return -1;
attr_found:
strlcpy(value, tmpattr->value, len);
remove_trailing_char(value, '\n');
dbg("found attribute '%s'", tmpattr->path);
return 0;
}
static void apply_format(struct udevice *udev, char *string, size_t maxsize,
struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device)
{
char temp[PATH_SIZE];
char temp2[PATH_SIZE];
char *tail, *pos, *cpos, *attr, *rest;
int len;
int i;
char c;
unsigned int next_free_number;
struct sysfs_class_device *class_dev_parent;
pos = string;
while (1) {
pos = strchr(pos, '%');
if (pos == NULL)
break;
pos[0] = '\0';
tail = pos+1;
len = get_format_len(&tail);
c = tail[0];
strlcpy(temp, tail+1, sizeof(temp));
tail = temp;
dbg("format=%c, string='%s', tail='%s'",c , string, tail);
attr = get_format_attribute(&tail);
switch (c) {
case 'p':
strlcat(string, udev->devpath, maxsize);
dbg("substitute kernel name '%s'", udev->kernel_name);
break;
case 'b':
strlcat(string, udev->bus_id, maxsize);
dbg("substitute bus_id '%s'", udev->bus_id);
break;
case 'k':
strlcat(string, udev->kernel_name, maxsize);
dbg("substitute kernel name '%s'", udev->kernel_name);
break;
case 'n':
strlcat(string, udev->kernel_number, maxsize);
dbg("substitute kernel number '%s'", udev->kernel_number);
break;
case 'm':
sprintf(temp2, "%d", minor(udev->devt));
strlcat(string, temp2, maxsize);
dbg("substitute minor number '%s'", temp2);
break;
case 'M':
sprintf(temp2, "%d", major(udev->devt));
strlcat(string, temp2, maxsize);
dbg("substitute major number '%s'", temp2);
break;
case 'c':
if (udev->program_result[0] == '\0')
break;
/* get part part of the result string */
i = 0;
if (attr != NULL)
i = strtoul(attr, &rest, 10);
if (i > 0) {
dbg("request part #%d of result string", i);
cpos = udev->program_result;
while (--i) {
while (cpos[0] != '\0' && !isspace(cpos[0]))
cpos++;
while (isspace(cpos[0]))
cpos++;
}
if (i > 0) {
err("requested part of result string not found");
break;
}
strlcpy(temp2, cpos, sizeof(temp2));
/* %{2+}c copies the whole string from the second part on */
if (rest[0] != '+') {
cpos = strchr(temp2, ' ');
if (cpos)
cpos[0] = '\0';
}
strlcat(string, temp2, maxsize);
dbg("substitute part of result string '%s'", temp2);
} else {
strlcat(string, udev->program_result, maxsize);
dbg("substitute result string '%s'", udev->program_result);
}
break;
case 's':
if (attr == NULL) {
dbg("missing attribute");
break;
}
if (find_sysfs_attribute(class_dev, sysfs_device, attr, temp2, sizeof(temp2)) != 0) {
struct sysfs_device *parent_device;
dbg("sysfs attribute '%s' not found, walk up the physical devices", attr);
parent_device = sysfs_get_device_parent(sysfs_device);
while (parent_device) {
dbg("looking at '%s'", parent_device->path);
if (find_sysfs_attribute(NULL, parent_device, attr, temp2, sizeof(temp2)) == 0)
break;
parent_device = sysfs_get_device_parent(parent_device);
}
if (!parent_device)
break;
}
/* strip trailing whitespace of sysfs value */
i = strlen(temp2);
while (i > 0 && isspace(temp2[i-1]))
temp2[--i] = '\0';
replace_untrusted_chars(temp2);
strlcat(string, temp2, maxsize);
dbg("substitute sysfs value '%s'", temp2);
break;
case '%':
strlcat(string, "%", maxsize);
pos++;
break;
case 'e':
next_free_number = find_free_number(udev, string);
if (next_free_number > 0) {
sprintf(temp2, "%d", next_free_number);
strlcat(string, temp2, maxsize);
}
break;
case 'P':
if (!class_dev)
break;
class_dev_parent = sysfs_get_classdev_parent(class_dev);
if (class_dev_parent != NULL) {
struct udevice udev_parent;
dbg("found parent '%s', get the node name", class_dev_parent->path);
udev_init_device(&udev_parent, NULL, NULL);
/* lookup the name in the udev_db with the DEVPATH of the parent */
if (udev_db_get_device(&udev_parent, &class_dev_parent->path[strlen(sysfs_path)]) == 0) {
strlcat(string, udev_parent.name, maxsize);
dbg("substitute parent node name'%s'", udev_parent.name);
} else
dbg("parent not found in database");
udev_cleanup_device(&udev_parent);
}
break;
case 'N':
if (udev->tmp_node[0] == '\0') {
dbg("create temporary device node for callout");
snprintf(udev->tmp_node, sizeof(udev->tmp_node), "%s/.tmp-%u-%u",
udev_root, major(udev->devt), minor(udev->devt));
udev->tmp_node[sizeof(udev->tmp_node)-1] = '\0';
udev_make_node(udev, udev->tmp_node, udev->devt, 0600, 0, 0);
}
strlcat(string, udev->tmp_node, maxsize);
dbg("substitute temporary device node name '%s'", udev->tmp_node);
break;
case 'r':
strlcat(string, udev_root, maxsize);
dbg("substitute udev_root '%s'", udev_root);
break;
default:
err("unknown substitution type '%%%c'", c);
break;
}
/* truncate to specified length */
if (len > 0)
pos[len] = '\0';
strlcat(string, tail, maxsize);
}
}
static int execute_program(struct udevice *udev, const char *path, char *value, int len)
{
int retval;
int count;
int status;
int fds[2];
pid_t pid;
char *pos;
char arg[PATH_SIZE];
char *argv[(sizeof(arg) / 2) + 1];
int i;
strlcpy(arg, path, sizeof(arg));
i = 0;
if (strchr(path, ' ')) {
pos = arg;
while (pos != NULL) {
if (pos[0] == '\'') {
/* don't separate if in apostrophes */
pos++;
argv[i] = strsep(&pos, "\'");
while (pos && pos[0] == ' ')
pos++;
} else {
argv[i] = strsep(&pos, " ");
}
dbg("arg[%i] '%s'", i, argv[i]);
i++;
}
argv[i] = NULL;
dbg("execute '%s' with parsed arguments", arg);
} else {
argv[0] = arg;
argv[1] = udev->subsystem;
argv[2] = NULL;
dbg("execute '%s' with subsystem '%s' argument", arg, argv[1]);
}
retval = pipe(fds);
if (retval != 0) {
err("pipe failed");
return -1;
}
pid = fork();
switch(pid) {
case 0:
/* child dup2 write side of pipe to STDOUT */
dup2(fds[1], STDOUT_FILENO);
retval = execv(arg, argv);
info(KEY_PROGRAM " execution of '%s' failed", path);
exit(1);
case -1:
err("fork of '%s' failed", path);
return -1;
default:
/* parent reads from fds[0] */
close(fds[1]);
retval = 0;
i = 0;
while (1) {
count = read(fds[0], value + i, len - i-1);
if (count < 0) {
err("read failed with '%s'", strerror(errno));
retval = -1;
}
if (count == 0)
break;
i += count;
if (i >= len-1) {
err("result len %d too short", len);
retval = -1;
break;
}
}
value[i] = '\0';
close(fds[0]);
waitpid(pid, &status, 0);
if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) {
dbg("exec program status 0x%x", status);
retval = -1;
}
}
if (!retval) {
remove_trailing_char(value, '\n');
dbg("result is '%s'", value);
replace_untrusted_chars(value);
} else
value[0] = '\0';
return retval;
}
static int compare_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, struct key_pair *pair)
{
char value[VALUE_SIZE];
int i;
if (find_sysfs_attribute(class_dev, sysfs_device, pair->name, value, sizeof(value)) != 0)
return -1;
/* strip trailing whitespace of value, if not asked to match for it */
if (!isspace(pair->value[strlen(pair->value)-1])) {
i = strlen(value);
while (i > 0 && isspace(value[i-1]))
value[--i] = '\0';
dbg("removed %i trailing whitespace chars from '%s'", strlen(value)-i, value);
}
dbg("compare attribute '%s' value '%s' with '%s'", pair->name, value, pair->value);
if (strcmp_pattern(pair->value, value) != 0)
return -1;
dbg("found matching attribute '%s' with value '%s'", pair->name, pair->value);
return 0;
}
static int match_rule(struct udevice *udev, struct udev_rule *rule,
struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device)
{
struct sysfs_device *parent_device = sysfs_device;
if (rule->kernel[0] != '\0') {
dbg("check for " KEY_KERNEL " rule->kernel='%s' class_dev->name='%s'",
rule->kernel, class_dev->name);
if (strcmp_pattern(rule->kernel, class_dev->name) != 0) {
dbg(KEY_KERNEL " is not matching");
if (rule->kernel_operation != KEY_OP_NOMATCH)
goto exit;
} else {
dbg(KEY_KERNEL " matches");
if (rule->kernel_operation == KEY_OP_NOMATCH)
goto exit;
}
dbg(KEY_KERNEL " key is true");
}
if (rule->subsystem[0] != '\0') {
dbg("check for " KEY_SUBSYSTEM " rule->subsystem='%s' class_dev->name='%s'",
rule->subsystem, class_dev->name);
if (strcmp_pattern(rule->subsystem, udev->subsystem) != 0) {
dbg(KEY_SUBSYSTEM " is not matching");
if (rule->subsystem_operation != KEY_OP_NOMATCH)
goto exit;
} else {
dbg(KEY_SUBSYSTEM " matches");
if (rule->subsystem_operation == KEY_OP_NOMATCH)
goto exit;
}
dbg(KEY_SUBSYSTEM " key is true");
}
if (rule->env_pair_count) {
int i;
dbg("check for " KEY_ENV " pairs");
for (i = 0; i < rule->env_pair_count; i++) {
struct key_pair *pair;
const char *value;
pair = &rule->env_pair[i];
value = getenv(pair->name);
if (!value) {
dbg(KEY_ENV "{'%s'} is not found", pair->name);
goto exit;
}
if (strcmp_pattern(pair->value, value) != 0) {
dbg(KEY_ENV "{'%s'} is not matching", pair->name);
if (pair->operation != KEY_OP_NOMATCH)
goto exit;
} else {
dbg(KEY_ENV "{'%s'} matches", pair->name);
if (pair->operation == KEY_OP_NOMATCH)
goto exit;
}
}
dbg(KEY_ENV " key is true");
}
/* walk up the chain of physical devices and find a match */
while (1) {
/* check for matching driver */
if (rule->driver[0] != '\0') {
if (parent_device == NULL) {
dbg("device has no sysfs_device");
goto exit;
}
dbg("check for " KEY_DRIVER " rule->driver='%s' sysfs_device->driver_name='%s'",
rule->driver, parent_device->driver_name);
if (strcmp_pattern(rule->driver, parent_device->driver_name) != 0) {
dbg(KEY_DRIVER " is not matching");
if (rule->driver_operation != KEY_OP_NOMATCH)
goto try_parent;
} else {
dbg(KEY_DRIVER " matches");
if (rule->driver_operation == KEY_OP_NOMATCH)
goto try_parent;
}
dbg(KEY_DRIVER " key is true");
}
/* check for matching bus value */
if (rule->bus[0] != '\0') {
if (parent_device == NULL) {
dbg("device has no sysfs_device");
goto exit;
}
dbg("check for " KEY_BUS " rule->bus='%s' sysfs_device->bus='%s'",
rule->bus, parent_device->bus);
if (strcmp_pattern(rule->bus, parent_device->bus) != 0) {
dbg(KEY_BUS " is not matching");
if (rule->bus_operation != KEY_OP_NOMATCH)
goto try_parent;
} else {
dbg(KEY_BUS " matches");
if (rule->bus_operation == KEY_OP_NOMATCH)
goto try_parent;
}
dbg(KEY_BUS " key is true");
}
/* check for matching bus id */
if (rule->id[0] != '\0') {
if (parent_device == NULL) {
dbg("device has no sysfs_device");
goto exit;
}
dbg("check " KEY_ID);
if (strcmp_pattern(rule->id, parent_device->bus_id) != 0) {
dbg(KEY_ID " is not matching");
if (rule->id_operation != KEY_OP_NOMATCH)
goto try_parent;
} else {
dbg(KEY_ID " matches");
if (rule->id_operation == KEY_OP_NOMATCH)
goto try_parent;
}
dbg(KEY_ID " key is true");
}
/* check for matching sysfs pairs */
if (rule->sysfs_pair_count) {
int i;
dbg("check " KEY_SYSFS " pairs");
for (i = 0; i < rule->sysfs_pair_count; i++) {
struct key_pair *pair;
pair = &rule->sysfs_pair[i];
if (compare_sysfs_attribute(class_dev, parent_device, pair) != 0) {
dbg(KEY_SYSFS "{'%s'} is not matching", pair->name);
if (pair->operation != KEY_OP_NOMATCH)
goto try_parent;
} else {
dbg(KEY_SYSFS "{'%s'} matches", pair->name);
if (pair->operation == KEY_OP_NOMATCH)
goto try_parent;
}
}
dbg(KEY_SYSFS " keys are true");
}
/* found matching physical device */
break;
try_parent:
dbg("try parent sysfs device");
parent_device = sysfs_get_device_parent(parent_device);
if (parent_device == NULL)
goto exit;
dbg("look at sysfs_device->path='%s'", parent_device->path);
dbg("look at sysfs_device->bus_id='%s'", parent_device->bus_id);
}
/* execute external program */
if (rule->program[0] != '\0') {
char program[PATH_SIZE];
dbg("check " KEY_PROGRAM);
strlcpy(program, rule->program, sizeof(program));
apply_format(udev, program, sizeof(program), class_dev, sysfs_device);
if (execute_program(udev, program, udev->program_result, sizeof(udev->program_result)) != 0) {
dbg(KEY_PROGRAM " returned nonzero");
if (rule->program_operation != KEY_OP_NOMATCH)
goto exit;
} else {
dbg(KEY_PROGRAM " returned successful");
if (rule->program_operation == KEY_OP_NOMATCH)
goto exit;
}
dbg(KEY_PROGRAM " key is true");
}
/* check for matching result of external program */
if (rule->result[0] != '\0') {
dbg("check for " KEY_RESULT " rule->result='%s', udev->program_result='%s'",
rule->result, udev->program_result);
if (strcmp_pattern(rule->result, udev->program_result) != 0) {
dbg(KEY_RESULT " is not matching");
if (rule->result_operation != KEY_OP_NOMATCH)
goto exit;
} else {
dbg(KEY_RESULT " matches");
if (rule->result_operation == KEY_OP_NOMATCH)
goto exit;
}
dbg(KEY_RESULT " key is true");
}
/* rule matches */
return 0;
exit:
return -1;
}
int udev_rules_get_name(struct udevice *udev, struct sysfs_class_device *class_dev)
{
struct sysfs_class_device *class_dev_parent;
struct sysfs_device *sysfs_device = NULL;
struct udev_rule *rule;
dbg("class_dev->name='%s'", class_dev->name);
/* Figure out where the "device"-symlink is at. For char devices this will
* always be in the class_dev->path. On block devices, only the main block
* device will have the device symlink in it's path. All partition devices
* need to look at the symlink in its parent directory.
*/
class_dev_parent = sysfs_get_classdev_parent(class_dev);
if (class_dev_parent != NULL) {
dbg("given class device has a parent, use this instead");
sysfs_device = sysfs_get_classdev_device(class_dev_parent);
} else {
sysfs_device = sysfs_get_classdev_device(class_dev);
}
if (sysfs_device) {
dbg("found devices device: path='%s', bus_id='%s', bus='%s'",
sysfs_device->path, sysfs_device->bus_id, sysfs_device->bus);
strlcpy(udev->bus_id, sysfs_device->bus_id, sizeof(udev->bus_id));
}
dbg("udev->kernel_name='%s'", udev->kernel_name);
/* look for a matching rule to apply */
list_for_each_entry(rule, &udev_rule_list, node) {
dbg("process rule");
if (match_rule(udev, rule, class_dev, sysfs_device) == 0) {
/* apply options */
if (rule->ignore_device) {
info("configured rule in '%s[%i]' applied, '%s' is ignored",
rule->config_file, rule->config_line, udev->kernel_name);
return -1;
}
if (rule->ignore_remove) {
udev->ignore_remove = 1;
dbg("remove event should be ignored");
}
/* apply all_partitions option only at a main block device */
if (rule->partitions && udev->type == DEV_BLOCK && udev->kernel_number[0] == '\0') {
udev->partitions = rule->partitions;
dbg("creation of partition nodes requested");
}
/* apply permissions */
if (rule->mode != 0000) {
udev->mode = rule->mode;
dbg("applied mode=%#o to '%s'", udev->mode, udev->kernel_name);
}
if (rule->owner[0] != '\0') {
strlcpy(udev->owner, rule->owner, sizeof(udev->owner));
apply_format(udev, udev->owner, sizeof(udev->owner), class_dev, sysfs_device);
dbg("applied owner='%s' to '%s'", udev->owner, udev->kernel_name);
}
if (rule->group[0] != '\0') {
strlcpy(udev->group, rule->group, sizeof(udev->group));
apply_format(udev, udev->group, sizeof(udev->group), class_dev, sysfs_device);
dbg("applied group='%s' to '%s'", udev->group, udev->kernel_name);
}
/* collect symlinks */
if (rule->symlink[0] != '\0') {
char temp[PATH_SIZE];
char *pos, *next;
info("configured rule in '%s[%i]' applied, added symlink '%s'",
rule->config_file, rule->config_line, rule->symlink);
strlcpy(temp, rule->symlink, sizeof(temp));
apply_format(udev, temp, sizeof(temp), class_dev, sysfs_device);
/* add multiple symlinks separated by spaces */
pos = temp;
next = strchr(temp, ' ');
while (next) {
next[0] = '\0';
info("add symlink '%s'", pos);
name_list_add(&udev->symlink_list, pos, 0);
pos = &next[1];
next = strchr(pos, ' ');
}
info("add symlink '%s'", pos);
name_list_add(&udev->symlink_list, pos, 0);
}
/* rule matches */
if (rule->name[0] != '\0') {
info("configured rule in '%s[%i]' applied, '%s' becomes '%s'",
rule->config_file, rule->config_line, udev->kernel_name, rule->name);
strlcpy(udev->name, rule->name, sizeof(udev->name));
apply_format(udev, udev->name, sizeof(udev->name), class_dev, sysfs_device);
strlcpy(udev->config_file, rule->config_file, sizeof(udev->config_file));
udev->config_line = rule->config_line;
if (udev->type != DEV_NET)
dbg("name, '%s' is going to have owner='%s', group='%s', mode=%#o partitions=%i",
udev->name, udev->owner, udev->group, udev->mode, udev->partitions);
break;
}
if (rule->last_rule) {
dbg("last rule to be applied");
break;
}
}
}
if (udev->name[0] == '\0') {
/* no rule matched, so we use the kernel name */
strlcpy(udev->name, udev->kernel_name, sizeof(udev->name));
info("no rule found, use kernel name '%s'", udev->name);
}
if (udev->tmp_node[0] != '\0') {
dbg("removing temporary device node");
unlink_secure(udev->tmp_node);
udev->tmp_node[0] = '\0';
}
return 0;
}