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Systemd/udev/udev_rules_parse.c

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/*
* Copyright (C) 2003,2004 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2003-2006 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 <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include <sys/stat.h>
#include <errno.h>
#include "udev.h"
#include "udev_rules.h"
#include "udev_selinux.h"
void udev_rules_iter_init(struct udev_rules *rules)
{
dbg("bufsize=%zi\n", rules->bufsize);
rules->current = 0;
}
struct udev_rule *udev_rules_iter_next(struct udev_rules *rules)
{
static struct udev_rule *rule;
if (!rules)
return NULL;
dbg("current=%zi\n", rules->current);
if (rules->current >= rules->bufsize) {
dbg("no more rules\n");
return NULL;
}
/* get next rule */
rule = (struct udev_rule *) (rules->buf + rules->current);
rules->current += sizeof(struct udev_rule) + rule->bufsize;
return rule;
}
struct udev_rule *udev_rules_iter_label(struct udev_rules *rules, const char *label)
{
static struct udev_rule *rule;
size_t start = rules->current;
next:
dbg("current=%zi\n", rules->current);
if (rules->current >= rules->bufsize) {
err("LABEL='%s' not found, GOTO will be ignored\n", label);
rules->current = start;
return NULL;
}
rule = (struct udev_rule *) (rules->buf + rules->current);
if (strcmp(&rule->buf[rule->label.val_off], label) != 0) {
dbg("moving forward, looking for label '%s'\n", label);
rules->current += sizeof(struct udev_rule) + rule->bufsize;
goto next;
}
dbg("found label '%s'\n", label);
return rule;
}
static int get_key(char **line, char **key, enum key_operation *operation, char **value)
{
char *linepos;
char *temp;
linepos = *line;
if (linepos == NULL && linepos[0] == '\0')
return -1;
/* skip whitespace */
while (isspace(linepos[0]) || linepos[0] == ',')
linepos++;
/* get the key */
if (linepos[0] == '\0')
return -1;
*key = linepos;
while (1) {
linepos++;
if (linepos[0] == '\0')
return -1;
if (isspace(linepos[0]))
break;
if (linepos[0] == '=')
break;
if ((linepos[0] == '+') || (linepos[0] == '!') || (linepos[0] == ':'))
if (linepos[1] == '=')
break;
}
/* remember end of key */
temp = linepos;
/* skip whitespace after key */
while (isspace(linepos[0]))
linepos++;
if (linepos[0] == '\0')
return -1;
/* get operation type */
if (linepos[0] == '=' && linepos[1] == '=') {
*operation = KEY_OP_MATCH;
linepos += 2;
dbg("operator=match\n");
} else if (linepos[0] == '!' && linepos[1] == '=') {
*operation = KEY_OP_NOMATCH;
linepos += 2;
dbg("operator=nomatch\n");
} else if (linepos[0] == '+' && linepos[1] == '=') {
*operation = KEY_OP_ADD;
linepos += 2;
dbg("operator=add\n");
} else if (linepos[0] == '=') {
*operation = KEY_OP_ASSIGN;
linepos++;
dbg("operator=assign\n");
} else if (linepos[0] == ':' && linepos[1] == '=') {
*operation = KEY_OP_ASSIGN_FINAL;
linepos += 2;
dbg("operator=assign_final\n");
} else
return -1;
/* terminate key */
temp[0] = '\0';
dbg("key='%s'\n", *key);
/* skip whitespace after operator */
while (isspace(linepos[0]))
linepos++;
if (linepos[0] == '\0')
return -1;
/* get the value*/
if (linepos[0] == '"')
linepos++;
else
return -1;
*value = linepos;
temp = strchr(linepos, '"');
if (!temp)
return -1;
temp[0] = '\0';
temp++;
dbg("value='%s'\n", *value);
/* move line to next key */
*line = temp;
return 0;
}
/* extract possible KEY{attr} */
static char *get_key_attribute(char *str)
{
char *pos;
char *attr;
attr = strchr(str, '{');
if (attr != NULL) {
attr++;
pos = strchr(attr, '}');
if (pos == NULL) {
err("missing closing brace for format\n");
return NULL;
}
pos[0] = '\0';
dbg("attribute='%s'\n", attr);
return attr;
}
return NULL;
}
static int add_rule_key(struct udev_rule *rule, struct key *key,
enum key_operation operation, const char *value)
{
size_t val_len = strnlen(value, PATH_SIZE);
key->operation = operation;
key->val_off = rule->bufsize;
strlcpy(rule->buf + rule->bufsize, value, val_len+1);
rule->bufsize += val_len+1;
return 0;
}
static int add_rule_key_pair(struct udev_rule *rule, struct key_pairs *pairs,
enum key_operation operation, const char *key, const char *value)
{
size_t key_len = strnlen(key, PATH_SIZE);
if (pairs->count >= PAIRS_MAX) {
err("skip, too many keys of the same type in a single rule\n");
return -1;
}
add_rule_key(rule, &pairs->keys[pairs->count].key, operation, value);
/* add the key-name of the pair */
pairs->keys[pairs->count].key_name_off = rule->bufsize;
strlcpy(rule->buf + rule->bufsize, key, key_len+1);
rule->bufsize += key_len+1;
pairs->count++;
return 0;
}
static int add_to_rules(struct udev_rules *rules, char *line, const char *filename, unsigned int lineno)
{
char buf[sizeof(struct udev_rule) + LINE_SIZE];
struct udev_rule *rule;
size_t rule_size;
int valid;
char *linepos;
char *attr;
size_t padding;
int physdev = 0;
int retval;
memset(buf, 0x00, sizeof(buf));
rule = (struct udev_rule *) buf;
rule->event_timeout = -1;
linepos = line;
valid = 0;
/* get all the keys */
while (1) {
char *key;
char *value;
enum key_operation operation = KEY_OP_UNSET;
retval = get_key(&linepos, &key, &operation, &value);
if (retval)
break;
if (strcasecmp(key, "ACTION") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid ACTION operation\n");
goto invalid;
}
add_rule_key(rule, &rule->action, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "DEVPATH") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid DEVPATH operation\n");
goto invalid;
}
add_rule_key(rule, &rule->devpath, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "KERNEL") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid KERNEL operation\n");
goto invalid;
}
add_rule_key(rule, &rule->kernel, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "SUBSYSTEM") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid SUBSYSTEM operation\n");
goto invalid;
}
/* bus, class, subsystem events should all be the same */
if (strcmp(value, "subsystem") == 0 ||
strcmp(value, "bus") == 0 ||
strcmp(value, "class") == 0) {
if (strcmp(value, "bus") == 0 || strcmp(value, "class") == 0)
err("'%s' must be specified as 'subsystem' \n"
"please fix it in %s:%u", value, filename, lineno);
add_rule_key(rule, &rule->subsystem, operation, "subsystem|class|bus");
} else
add_rule_key(rule, &rule->subsystem, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "DRIVER") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid DRIVER operation\n");
goto invalid;
}
add_rule_key(rule, &rule->driver, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "ATTR{", sizeof("ATTR{")-1) == 0) {
attr = get_key_attribute(key + sizeof("ATTR")-1);
if (attr == NULL) {
err("error parsing ATTR attribute\n");
goto invalid;
}
if (add_rule_key_pair(rule, &rule->attr, operation, attr, value) != 0)
goto invalid;
valid = 1;
continue;
}
if (strcasecmp(key, "KERNELS") == 0 ||
strcasecmp(key, "ID") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid KERNELS operation\n");
goto invalid;
}
add_rule_key(rule, &rule->kernels, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "SUBSYSTEMS") == 0 ||
strcasecmp(key, "BUS") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid SUBSYSTEMS operation\n");
goto invalid;
}
add_rule_key(rule, &rule->subsystems, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "DRIVERS") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid DRIVERS operation\n");
goto invalid;
}
add_rule_key(rule, &rule->drivers, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "ATTRS{", sizeof("ATTRS{")-1) == 0 ||
strncasecmp(key, "SYSFS{", sizeof("SYSFS{")-1) == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid ATTRS operation\n");
goto invalid;
}
attr = get_key_attribute(key + sizeof("ATTRS")-1);
if (attr == NULL) {
err("error parsing ATTRS attribute\n");
goto invalid;
}
if (strncmp(attr, "device/", 7) == 0)
err("the 'device' link is deprecated and will be removed from a future kernel, \n"
"please fix it in %s:%u", filename, lineno);
else if (strstr(attr, "../") != NULL)
err("do not reference parent sysfs directories directly, that may break with a future kernel, \n"
"please fix it in %s:%u", filename, lineno);
if (add_rule_key_pair(rule, &rule->attrs, operation, attr, value) != 0)
goto invalid;
valid = 1;
continue;
}
if (strncasecmp(key, "ENV{", sizeof("ENV{")-1) == 0) {
attr = get_key_attribute(key + sizeof("ENV")-1);
if (attr == NULL) {
err("error parsing ENV attribute\n");
goto invalid;
}
if (strncmp(attr, "PHYSDEV", 7) == 0)
physdev = 1;
if (add_rule_key_pair(rule, &rule->env, operation, attr, value) != 0)
goto invalid;
valid = 1;
continue;
}
if (strcasecmp(key, "PROGRAM") == 0) {
add_rule_key(rule, &rule->program, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "RESULT") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid RESULT operation\n");
goto invalid;
}
add_rule_key(rule, &rule->result, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "IMPORT", sizeof("IMPORT")-1) == 0) {
attr = get_key_attribute(key + sizeof("IMPORT")-1);
if (attr != NULL && strstr(attr, "program")) {
dbg("IMPORT will be executed\n");
rule->import_type = IMPORT_PROGRAM;
} else if (attr != NULL && strstr(attr, "file")) {
dbg("IMPORT will be included as file\n");
rule->import_type = IMPORT_FILE;
} else if (attr != NULL && strstr(attr, "parent")) {
dbg("IMPORT will include the parent values\n");
rule->import_type = IMPORT_PARENT;
} else {
/* figure it out if it is executable */
char file[PATH_SIZE];
char *pos;
struct stat statbuf;
strlcpy(file, value, sizeof(file));
pos = strchr(file, ' ');
if (pos)
pos[0] = '\0';
/* allow programs in /lib/udev called without the path */
if (strchr(file, '/') == NULL) {
strlcpy(file, UDEV_PREFIX "/lib/udev/", sizeof(file));
strlcat(file, value, sizeof(file));
pos = strchr(file, ' ');
if (pos)
pos[0] = '\0';
}
dbg("IMPORT auto mode for '%s'\n", file);
if (!lstat(file, &statbuf) && (statbuf.st_mode & S_IXUSR)) {
dbg("IMPORT is executable, will be executed (autotype)\n");
rule->import_type = IMPORT_PROGRAM;
} else {
dbg("IMPORT is not executable, will be included as file (autotype)\n");
rule->import_type = IMPORT_FILE;
}
}
add_rule_key(rule, &rule->import, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "TEST", sizeof("TEST")-1) == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid TEST operation\n");
goto invalid;
}
attr = get_key_attribute(key + sizeof("TEST")-1);
if (attr != NULL)
rule->test_mode_mask = strtol(attr, NULL, 8);
add_rule_key(rule, &rule->test, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "RUN", sizeof("RUN")-1) == 0) {
attr = get_key_attribute(key + sizeof("RUN")-1);
if (attr != NULL) {
if (strstr(attr, "ignore_error"))
rule->run_ignore_error = 1;
}
add_rule_key(rule, &rule->run, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "WAIT_FOR") == 0 || strcasecmp(key, "WAIT_FOR_SYSFS") == 0) {
add_rule_key(rule, &rule->wait_for, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "LABEL") == 0) {
add_rule_key(rule, &rule->label, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "GOTO") == 0) {
add_rule_key(rule, &rule->goto_label, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "NAME", sizeof("NAME")-1) == 0) {
attr = get_key_attribute(key + sizeof("NAME")-1);
if (attr != NULL) {
if (strstr(attr, "all_partitions") != NULL) {
dbg("creation of partition nodes requested\n");
rule->partitions = DEFAULT_PARTITIONS_COUNT;
}
if (strstr(attr, "ignore_remove") != NULL) {
dbg("remove event should be ignored\n");
rule->ignore_remove = 1;
}
}
if (value[0] == '\0')
dbg("name empty, node creation supressed\n");
add_rule_key(rule, &rule->name, operation, value);
continue;
}
if (strcasecmp(key, "SYMLINK") == 0) {
if (operation == KEY_OP_MATCH ||
operation == KEY_OP_NOMATCH)
add_rule_key(rule, &rule->symlink_match, operation, value);
else
add_rule_key(rule, &rule->symlink, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "OWNER") == 0) {
valid = 1;
if (rules->resolve_names && (!strchr(value, '$') && !strchr(value, '%'))) {
char *endptr;
strtoul(value, &endptr, 10);
if (endptr[0] != '\0') {
char owner[32];
uid_t uid = lookup_user(value);
dbg("replacing username='%s' by id=%i\n", value, uid);
sprintf(owner, "%u", (unsigned int) uid);
add_rule_key(rule, &rule->owner, operation, owner);
continue;
}
}
add_rule_key(rule, &rule->owner, operation, value);
continue;
}
if (strcasecmp(key, "GROUP") == 0) {
valid = 1;
if (rules->resolve_names && (!strchr(value, '$') && !strchr(value, '%'))) {
char *endptr;
strtoul(value, &endptr, 10);
if (endptr[0] != '\0') {
char group[32];
gid_t gid = lookup_group(value);
dbg("replacing groupname='%s' by id=%i\n", value, gid);
sprintf(group, "%u", (unsigned int) gid);
add_rule_key(rule, &rule->group, operation, group);
continue;
}
}
add_rule_key(rule, &rule->group, operation, value);
continue;
}
if (strcasecmp(key, "MODE") == 0) {
add_rule_key(rule, &rule->mode, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "OPTIONS") == 0) {
const char *pos;
if (strstr(value, "last_rule") != NULL) {
dbg("last rule to be applied\n");
rule->last_rule = 1;
}
if (strstr(value, "ignore_device") != NULL) {
dbg("device should be ignored\n");
rule->ignore_device = 1;
}
if (strstr(value, "ignore_remove") != NULL) {
dbg("remove event should be ignored\n");
rule->ignore_remove = 1;
}
pos = strstr(value, "link_priority=");
if (pos != NULL) {
rule->link_priority = atoi(&pos[strlen("link_priority=")]);
dbg("link priority=%i\n", rule->link_priority);
}
pos = strstr(value, "event_timeout=");
if (pos != NULL) {
rule->event_timeout = atoi(&pos[strlen("event_timeout=")]);
dbg("event timout=%i\n", rule->event_timeout);
}
pos = strstr(value, "string_escape=");
if (pos != NULL) {
pos = &pos[strlen("string_escape=")];
if (strncmp(pos, "none", strlen("none")) == 0)
rule->string_escape = ESCAPE_NONE;
else if (strncmp(pos, "replace", strlen("replace")) == 0)
rule->string_escape = ESCAPE_REPLACE;
}
if (strstr(value, "all_partitions") != NULL) {
dbg("creation of partition nodes requested\n");
rule->partitions = DEFAULT_PARTITIONS_COUNT;
}
valid = 1;
continue;
}
err("unknown key '%s' in %s:%u\n", key, filename, lineno);
}
if (physdev && rule->wait_for.operation == KEY_OP_UNSET)
err("PHYSDEV* values are deprecated and will be removed from a future kernel, \n"
"please fix it in %s:%u", filename, lineno);
/* skip line if not any valid key was found */
if (!valid)
goto invalid;
/* grow buffer and add rule */
rule_size = sizeof(struct udev_rule) + rule->bufsize;
padding = (sizeof(size_t) - rule_size % sizeof(size_t)) % sizeof(size_t);
dbg("add %zi padding bytes\n", padding);
rule_size += padding;
rule->bufsize += padding;
rules->buf = realloc(rules->buf, rules->bufsize + rule_size);
if (!rules->buf) {
err("realloc failed\n");
goto exit;
}
dbg("adding rule to offset %zi\n", rules->bufsize);
memcpy(rules->buf + rules->bufsize, rule, rule_size);
rules->bufsize += rule_size;
exit:
return 0;
invalid:
err("invalid rule '%s:%u'\n", filename, lineno);
return -1;
}
static int parse_file(struct udev_rules *rules, const char *filename)
{
char line[LINE_SIZE];
char *bufline;
unsigned int lineno;
char *buf;
size_t bufsize;
size_t cur;
size_t count;
int retval = 0;
if (file_map(filename, &buf, &bufsize) != 0) {
err("can't open '%s' as rules file: %s\n", filename, strerror(errno));
return -1;
}
info("reading '%s' as rules file\n", filename);
/* loop through the whole file */
cur = 0;
lineno = 0;
while (cur < bufsize) {
unsigned int i, j;
count = buf_get_line(buf, bufsize, cur);
bufline = &buf[cur];
cur += count+1;
lineno++;
/* eat the whitespace */
while ((count > 0) && isspace(bufline[0])) {
bufline++;
count--;
}
if (count == 0)
continue;
/* see if this is a comment */
if (bufline[0] == COMMENT_CHARACTER)
continue;
if (count >= sizeof(line)) {
err("line too long, rule skipped '%s:%u'\n", filename, lineno);
continue;
}
/* skip backslash and newline from multiline rules */
for (i = j = 0; i < count; i++) {
if (bufline[i] == '\\' && bufline[i+1] == '\n')
continue;
line[j++] = bufline[i];
}
line[j] = '\0';
dbg("read '%s'\n", line);
add_to_rules(rules, line, filename, lineno);
}
file_unmap(buf, bufsize);
return retval;
}
int udev_rules_init(struct udev_rules *rules, int resolve_names)
{
struct stat statbuf;
char filename[PATH_MAX];
LIST_HEAD(name_list);
LIST_HEAD(sort_list);
struct name_entry *name_loop, *name_tmp;
struct name_entry *sort_loop, *sort_tmp;
int retval = 0;
memset(rules, 0x00, sizeof(struct udev_rules));
rules->resolve_names = resolve_names;
if (udev_rules_dir[0] != '\0') {
/* custom rules location for testing */
add_matching_files(&name_list, udev_rules_dir, ".rules");
} else {
/* read default rules */
add_matching_files(&name_list, UDEV_PREFIX "/lib/udev/rules.d", ".rules");
/* read user/custom rules */
add_matching_files(&sort_list, SYSCONFDIR "/udev/rules.d", ".rules");
/* read dynamic/temporary rules */
strlcpy(filename, udev_root, sizeof(filename));
strlcat(filename, "/.udev/rules.d", sizeof(filename));
if (stat(filename, &statbuf) != 0) {
create_path(filename);
selinux_setfscreatecon(filename, NULL, S_IFDIR|0755);
mkdir(filename, 0755);
selinux_resetfscreatecon();
}
add_matching_files(&sort_list, filename, ".rules");
/* sort all rules files by basename into list of files */
list_for_each_entry_safe(sort_loop, sort_tmp, &sort_list, node) {
const char *sort_base = strrchr(sort_loop->name, '/');
if (sort_base == NULL)
continue;
list_for_each_entry_safe(name_loop, name_tmp, &name_list, node) {
const char *name_base = strrchr(name_loop->name, '/');
if (name_base == NULL)
continue;
if (strcmp(name_base, sort_base) > 0)
break;
}
list_move_tail(&sort_loop->node, &name_loop->node);
}
}
/* parse list of files */
list_for_each_entry_safe(name_loop, name_tmp, &name_list, node) {
if (stat(name_loop->name, &statbuf) == 0) {
if (statbuf.st_size)
parse_file(rules, name_loop->name);
else
dbg("empty rules file '%s'\n", name_loop->name);
} else
err("could not read '%s': %s\n", name_loop->name, strerror(errno));
list_del(&name_loop->node);
free(name_loop);
}
return retval;
}
void udev_rules_cleanup(struct udev_rules *rules)
{
if (rules->buf) {
free(rules->buf);
rules->buf = NULL;
}
}
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