From: Kay Sievers Date: Fri, 24 Oct 2008 08:51:04 +0000 (+0200) Subject: cache uid/gid during rule parsing X-Git-Tag: 174~1388 X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=154a7b8428731fb90cc639439fcdb98003471298 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. --- diff --git a/udev/test-udev.c b/udev/test-udev.c index 76045132b..ff1c353e6 100644 --- a/udev/test-udev.c +++ b/udev/test-udev.c @@ -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)); diff --git a/udev/udev-rules.c b/udev/udev-rules.c index 535ec3f14..b19edc5ed 100644 --- a/udev/udev-rules.c +++ b/udev/udev-rules.c @@ -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); } diff --git a/udev/udevadm-test.c b/udev/udevadm-test.c index ceeead0c8..2c8e0bff9 100644 --- a/udev/udevadm-test.c +++ b/udev/udevadm-test.c @@ -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;