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Systemd/udev_rules_parse.c
Kay Sievers 95776dc6ec consistent key naming to match only the event device or include all parent devices 
This scheme is more consistent and makes it obvious if a match happens
against the event device only, or the full chain of parent devices.

The old key names are now:
  BUS -> SUBSYSTEMS
  ID -> KERNELS
  SYSFS -> ATTRS
  DRIVER -> DRIVERS

Match keys for the event device:
  KERNEL
  SUBSYSTEM
  ATTR
  DRIVER (in a future release, for now the same as DRIVERS)

Match keys for all devices along the parent device chain:
  KERNELS
  SUBSYSTEMS
  ATTRS
  DRIVERS

ID, BUS, SYSFS are no longer mentioned in the man page but still work.
DRIVER must be converted to DRIVERS to match the new scheme. For now,
an error is logged, if DRIVER is used. In a future release, the DRIVER
key behaviour will change.
2006-08-19 16:06:25 +02:00

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/*
* udev_rules_parse.c
*
* Copyright (C) 2003,2004 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 <ctype.h>
#include <unistd.h>
#include <sys/stat.h>
#include <errno.h>
#include "udev.h"
#include "udev_rules.h"
void udev_rules_iter_init(struct udev_rules *rules)
{
dbg("bufsize=%zi", 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", rules->current);
if (rules->current >= rules->bufsize) {
dbg("no more rules");
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;
next:
dbg("current=%zi", rules->current);
if (rules->current >= rules->bufsize) {
dbg("no more rules");
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'", label);
rules->current += sizeof(struct udev_rule) + rule->bufsize;
goto next;
}
dbg("found label '%s'", 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] == '+')
break;
if (linepos[0] == '!')
break;
if (linepos[0] == ':')
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");
} else if (linepos[0] == '!' && linepos[1] == '=') {
*operation = KEY_OP_NOMATCH;
linepos += 2;
dbg("operator=nomatch");
} else if (linepos[0] == '+' && linepos[1] == '=') {
*operation = KEY_OP_ADD;
linepos += 2;
dbg("operator=add");
} else if (linepos[0] == '=') {
*operation = KEY_OP_ASSIGN;
linepos++;
dbg("operator=assign");
} else if (linepos[0] == ':' && linepos[1] == '=') {
*operation = KEY_OP_ASSIGN_FINAL;
linepos += 2;
dbg("operator=assign_final");
} else
return -1;
/* terminate key */
temp[0] = '\0';
dbg("key='%s'", *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'", *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");
return NULL;
}
pos[0] = '\0';
dbg("attribute='%s'", 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 in a single rule");
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)
{
struct udev_rule *rule;
size_t rule_size;
int valid;
char *linepos;
char *attr;
size_t padding;
int retval;
/* get all the keys */
rule = calloc(1, sizeof (struct udev_rule) + LINE_SIZE);
if (!rule) {
err("malloc failed");
return -1;
}
linepos = line;
valid = 0;
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");
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");
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");
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");
goto invalid;
}
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");
goto invalid;
}
err("DRIVER== will change in a future relase, "
"please use DRIVERS== in %s:%u", filename, lineno);
/* FIXME: this should be rule->driver to match only the event device */
add_rule_key(rule, &rule->drivers, operation, value);
valid = 1;
continue;
}
if (strncasecmp(key, "ATTR", sizeof("ATTR")-1) == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid ATTR operation");
goto invalid;
}
attr = get_key_attribute(key + sizeof("ATTR")-1);
if (attr == NULL) {
err("error parsing ATTR attribute in '%s'", line);
continue;
}
add_rule_key_pair(rule, &rule->attr, operation, attr, value);
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");
goto invalid;
}
add_rule_key(rule, &rule->kernels, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "SUBSYTEMS") == 0 ||
strcasecmp(key, "BUS") == 0) {
if (operation != KEY_OP_MATCH &&
operation != KEY_OP_NOMATCH) {
err("invalid SUBSYSTEMS operation");
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");
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 ATTRSS operation");
goto invalid;
}
attr = get_key_attribute(key + sizeof("ATTRS")-1);
if (attr == NULL) {
err("error parsing ATTRS attribute in '%s'", line);
continue;
}
add_rule_key_pair(rule, &rule->attrs, operation, attr, value);
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");
continue;
}
add_rule_key_pair(rule, &rule->env, operation, attr, value);
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");
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 && strstr(attr, "program")) {
dbg("IMPORT will be executed");
rule->import_type = IMPORT_PROGRAM;
} else if (attr && strstr(attr, "file")) {
dbg("IMPORT will be included as file");
rule->import_type = IMPORT_FILE;
} else if (attr && strstr(attr, "parent")) {
dbg("IMPORT will include the parent values");
rule->import_type = IMPORT_PARENT;
} else {
/* figure it out if it is executable */
char file[PATH_SIZE];
char *pos;
struct stat stats;
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, "/lib/udev/", sizeof(file));
strlcat(file, value, sizeof(file));
pos = strchr(file, ' ');
if (pos)
pos[0] = '\0';
}
dbg("IMPORT auto mode for '%s'", file);
if (!lstat(file, &stats) && (stats.st_mode & S_IXUSR)) {
dbg("IMPORT is executable, will be executed (autotype)");
rule->import_type = IMPORT_PROGRAM;
} else {
dbg("IMPORT is not executable, will be included as file (autotype)");
rule->import_type = IMPORT_FILE;
}
}
add_rule_key(rule, &rule->import, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "RUN") == 0) {
add_rule_key(rule, &rule->run, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "WAIT_FOR_SYSFS") == 0) {
add_rule_key(rule, &rule->wait_for_sysfs, 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");
rule->partitions = DEFAULT_PARTITIONS_COUNT;
}
if (strstr(attr, "ignore_remove") != NULL) {
dbg("remove event should be ignored");
rule->ignore_remove = 1;
}
}
if (value[0] == '\0')
dbg("name empty, node creation supressed");
add_rule_key(rule, &rule->name, operation, value);
continue;
}
if (strcasecmp(key, "SYMLINK") == 0) {
add_rule_key(rule, &rule->symlink, operation, value);
valid = 1;
continue;
}
if (strcasecmp(key, "OWNER") == 0) {
valid = 1;
if (rules->resolve_names && (!strchr(value, '$') && !strchr(value, '%'))) {
char *endptr;
strtoul(value, &endptr, 10);
if (endptr[0] != '\0') {
char owner[32];
uid_t uid = lookup_user(value);
dbg("replacing username='%s' by id=%i", value, uid);
sprintf(owner, "%u", (unsigned int) uid);
add_rule_key(rule, &rule->owner, operation, owner);
continue;
}
}
add_rule_key(rule, &rule->owner, operation, value);
continue;
}
if (strcasecmp(key, "GROUP") == 0) {
valid = 1;
if (rules->resolve_names && (!strchr(value, '$') && !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", 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) {
rule->mode = strtol(value, NULL, 8);
rule->mode_operation = operation;
valid = 1;
continue;
}
if (strcasecmp(key, "OPTIONS") == 0) {
if (strstr(value, "last_rule") != NULL) {
dbg("last rule to be applied");
rule->last_rule = 1;
}
if (strstr(value, "ignore_device") != NULL) {
dbg("device should be ignored");
rule->ignore_device = 1;
}
if (strstr(value, "ignore_remove") != NULL) {
dbg("remove event should be ignored");
rule->ignore_remove = 1;
}
if (strstr(value, "all_partitions") != NULL) {
dbg("creation of partition nodes requested");
rule->partitions = DEFAULT_PARTITIONS_COUNT;
}
valid = 1;
continue;
}
err("unknown key '%s' in %s:%u", key, 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", padding);
rule_size += padding;
rule->bufsize += padding;
rules->buf = realloc(rules->buf, rules->bufsize + rule_size);
if (!rules->buf) {
err("realloc failed");
goto exit;
}
dbg("adding rule to offset %zi", rules->bufsize);
memcpy(rules->buf + rules->bufsize, rule, rule_size);
rules->bufsize += rule_size;
exit:
free(rule);
return 0;
invalid:
free(rule);
err("invalid rule '%s:%u'", 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", filename, strerror(errno));
return -1;
}
dbg("reading '%s' as rules file", 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'", 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'", 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 stats;
int retval;
memset(rules, 0x00, sizeof(struct udev_rules));
rules->resolve_names = resolve_names;
/* parse rules file or all matching files in directory */
if (stat(udev_rules_filename, &stats) != 0)
return -1;
if ((stats.st_mode & S_IFMT) != S_IFDIR) {
dbg("parse single rules file '%s'", udev_rules_filename);
retval = parse_file(rules, udev_rules_filename);
} else {
struct name_entry *name_loop, *name_tmp;
LIST_HEAD(name_list);
dbg("parse rules directory '%s'", udev_rules_filename);
retval = add_matching_files(&name_list, udev_rules_filename, RULEFILE_SUFFIX);
list_for_each_entry_safe(name_loop, name_tmp, &name_list, node) {
if (stat(name_loop->name, &stats) == 0) {
if (stats.st_size)
parse_file(rules, name_loop->name);
else
dbg("empty rules file '%s'", name_loop->name);
} else
err("could not read '%s': %s", 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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