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cache uid/gid during rule parsing 

This cuts down the number of parsing /etc/group from ~700 to 11,
with some large rule files installed.
This commit is contained in:
Kay Sievers 2008-10-24 10:51:04 +02:00
parent f6bb9e981a
commit 154a7b8428
3 changed files with 139 additions and 18 deletions
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2
udev/test-udev.c
View File

@ -81,7 +81,7 @@ int main(int argc, char *argv[])
goto exit;
}
rules = udev_rules_new(udev, 0);
rules = udev_rules_new(udev, 1);
util_strlcpy(syspath, udev_get_sys_path(udev), sizeof(syspath));
util_strlcat(syspath, devpath, sizeof(syspath));

153
udev/udev-rules.c
View File

@ -31,6 +31,7 @@
#define PREALLOC_TOKEN 2048
#define PREALLOC_STRBUF 32 * 1024
/* KEY=="", KEY!="", KEY+="", KEY="", KEY:="" */
enum key_operation {
KEY_OP_UNSET,
KEY_OP_MATCH,
@ -48,6 +49,7 @@ static const char *operation_str[] = {
[KEY_OP_ASSIGN_FINAL] = "assign-final",
};
/* tokens of a rule are sorted/handled in this order */
enum token_type {
TK_UNDEF,
TK_RULE,
@ -187,19 +189,39 @@ struct rule_tmp {
unsigned int token_cur;
};
struct uid_gid {
unsigned int name_off;
union {
uid_t uid;
gid_t gid;
};
};
struct udev_rules {
struct udev *udev;
int resolve_names;
/* every key in the rules file becomes a token */
struct token *tokens;
unsigned int token_cur;
unsigned int token_max;
/* all key strings are copied to a single string buffer */
char *buf;
size_t buf_cur;
size_t buf_max;
unsigned int buf_count;
/* during rule parsing, we cache uid/gid lookup results */
struct uid_gid *uids;
unsigned int uids_cur;
unsigned int uids_max;
struct uid_gid *gids;
unsigned int gids_cur;
unsigned int gids_max;
};
/* we could lookup and return existing strings, or tails of strings */
/* NOTE: we could lookup and return existing strings, or tails of strings */
static int add_string(struct udev_rules *rules, const char *str)
{
size_t len = strlen(str)+1;
@ -216,8 +238,8 @@ static int add_string(struct udev_rules *rules, const char *str)
/* double the buffer size */
add = rules->buf_max;
if (add < len)
add = len * 2;
if (add < len * 8)
add = len * 8;
buf = realloc(rules->buf, rules->buf_max + add);
if (buf == NULL)
@ -243,8 +265,8 @@ static int add_token(struct udev_rules *rules, struct token *token)
/* double the buffer size */
add = rules->token_max;
if (add < 1)
add = 2;
if (add < 8)
add = 8;
tokens = realloc(rules->tokens, (rules->token_max + add ) * sizeof(struct token));
if (tokens == NULL)
@ -258,6 +280,92 @@ static int add_token(struct udev_rules *rules, struct token *token)
return 0;
}
static uid_t add_uid(struct udev_rules *rules, const char *owner)
{
unsigned int i;
uid_t uid;
unsigned int off;
/* lookup, if we know it already */
for (i = 0; i < rules->uids_cur; i++) {
off = rules->uids[i].name_off;
if (strcmp(&rules->buf[off], owner) == 0) {
uid = rules->uids[i].uid;
dbg(rules->udev, "return existing %u for '%s'\n", uid, owner);
return uid;
}
}
uid = util_lookup_user(rules->udev, owner);
/* grow buffer if needed */
if (rules->uids_cur+1 >= rules->uids_max) {
struct uid_gid *uids;
unsigned int add;
/* double the buffer size */
add = rules->uids_max;
if (add < 1)
add = 8;
uids = realloc(rules->uids, (rules->uids_max + add ) * sizeof(struct uid_gid));
if (uids == NULL)
return uid;
info(rules->udev, "extend uids from %u to %u\n", rules->uids_max, rules->uids_max + add);
rules->uids = uids;
rules->uids_max += add;
}
rules->uids[rules->uids_cur].uid = uid;
off = add_string(rules, owner);
if (off <= 0)
return uid;
rules->uids[rules->uids_cur].name_off = off;
rules->uids_cur++;
return uid;
}
static gid_t add_gid(struct udev_rules *rules, const char *group)
{
unsigned int i;
gid_t gid;
unsigned int off;
/* lookup, if we know it already */
for (i = 0; i < rules->gids_cur; i++) {
off = rules->gids[i].name_off;
if (strcmp(&rules->buf[off], group) == 0) {
gid = rules->gids[i].gid;
info(rules->udev, "return existing %u for '%s'\n", gid, group);
return gid;
}
}
gid = util_lookup_group(rules->udev, group);
/* grow buffer if needed */
if (rules->gids_cur+1 >= rules->gids_max) {
struct uid_gid *gids;
unsigned int add;
/* double the buffer size */
add = rules->gids_max;
if (add < 1)
add = 8;
gids = realloc(rules->gids, (rules->gids_max + add ) * sizeof(struct uid_gid));
if (gids == NULL)
return gid;
info(rules->udev, "extend gids from %u to %u\n", rules->gids_max, rules->gids_max + add);
rules->gids = gids;
rules->gids_max += add;
}
rules->gids[rules->gids_cur].gid = gid;
off = add_string(rules, group);
if (off <= 0)
return gid;
rules->gids[rules->gids_cur].name_off = off;
rules->gids_cur++;
return gid;
}
static int import_property_from_string(struct udev_device *dev, char *line)
{
struct udev *udev = udev_device_get_udev(dev);
@ -1148,7 +1256,7 @@ static int add_rule(struct udev_rules *rules, char *line,
if (endptr[0] == '\0') {
rule_add_token(&rule_tmp, TK_A_OWNER_ID, op, NULL, &uid);
} else if (rules->resolve_names && strchr("$%", value[0]) == NULL) {
uid = util_lookup_user(rules->udev, value);
uid = add_uid(rules, value);
rule_add_token(&rule_tmp, TK_A_OWNER_ID, op, NULL, &uid);
} else {
rule_add_token(&rule_tmp, TK_A_OWNER, op, value, NULL);
@ -1165,7 +1273,7 @@ static int add_rule(struct udev_rules *rules, char *line,
if (endptr[0] == '\0') {
rule_add_token(&rule_tmp, TK_A_GROUP_ID, op, NULL, &gid);
} else if (rules->resolve_names && strchr("$%", value[0]) == NULL) {
gid = util_lookup_group(rules->udev, value);
gid = add_gid(rules, value);
rule_add_token(&rule_tmp, TK_A_GROUP_ID, op, NULL, &gid);
} else {
rule_add_token(&rule_tmp, TK_A_GROUP, op, value, NULL);
@ -1476,7 +1584,16 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names)
end_token.type = TK_END;
add_token(rules, &end_token);
/* shrink allocate buffers */
/* link all TK_RULE tokens to be able to fast-forward to next TK_RULE */
prev_rule = 0;
for (i = 1; i < rules->token_cur; i++) {
if (rules->tokens[i].type == TK_RULE) {
rules->tokens[prev_rule].rule.next_rule = i;
prev_rule = i;
}
}
/* shrink allocated token and string buffer */
if (rules->token_cur < rules->token_max) {
struct token *tokens;
@ -1498,14 +1615,16 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names)
info(udev, "shrunk to %lu bytes tokens (%u * %zu bytes), %zu bytes buffer\n",
rules->token_max * sizeof(struct token), rules->token_max, sizeof(struct token), rules->buf_max);
/* link all TK_RULE tokens to be able to fast-forward to next TK_RULE */
prev_rule = 0;
for (i = 1; i < rules->token_cur; i++) {
if (rules->tokens[i].type == TK_RULE) {
rules->tokens[prev_rule].rule.next_rule = i;
prev_rule = i;
}
}
/* cleanup uid/gid cache */
free(rules->uids);
rules->uids = NULL;
rules->uids_cur = 0;
rules->uids_max = 0;
free(rules->gids);
rules->gids = NULL;
rules->gids_cur = 0;
rules->gids_max = 0;
dump_rules(rules);
return rules;
}
@ -1516,6 +1635,8 @@ void udev_rules_unref(struct udev_rules *rules)
return;
free(rules->tokens);
free(rules->buf);
free(rules->uids);
free(rules->gids);
free(rules);
}

2
udev/udevadm-test.c
View File

@ -89,7 +89,7 @@ int udevadm_test(struct udev *udev, int argc, char *argv[])
"some values may be different, or not available at a simulation run.\n"
"\n");
rules = udev_rules_new(udev, 0);
rules = udev_rules_new(udev, 1);
if (rules == NULL) {
fprintf(stderr, "error reading rules\n");
rc = 1;