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// SPDX-License-Identifier: GPL-3.0-or-later
#include "cached-uid-username.h"
// --------------------------------------------------------------------------------------------------------------------
// hashtable for caching uid to username mappings
// key is the uid, value is username (STRING)
#define SIMPLE_HASHTABLE_KEY_TYPE uid_t
#define SIMPLE_HASHTABLE_VALUE_TYPE CACHED_USERNAME
#define SIMPLE_HASHTABLE_VALUE2KEY_FUNCTION cached_username_to_uid_ptr
#define SIMPLE_HASHTABLE_COMPARE_KEYS_FUNCTION compar_uid_ptr
#define SIMPLE_HASHTABLE_NAME _USERNAMES_CACHE
#include "libnetdata/simple_hashtable/simple_hashtable.h"
static struct {
bool initialized;
SPINLOCK spinlock;
SIMPLE_HASHTABLE_USERNAMES_CACHE ht;
} user_cache = {
.initialized = false,
.spinlock = NETDATA_SPINLOCK_INITIALIZER,
.ht = { 0 },
};
static uid_t *cached_username_to_uid_ptr(CACHED_USERNAME *cu) {
return &cu->uid;
}
static bool compar_uid_ptr(uid_t *a, uid_t *b) {
return *a == *b;
}
void cached_username_populate_by_uid(uid_t uid, const char *username, uint32_t version) {
internal_fatal(!user_cache.initialized, "system-users cache needs to be initialized");
if(!username || !*username) return;
spinlock_lock(&user_cache.spinlock);
XXH64_hash_t hash = XXH3_64bits(&uid, sizeof(uid));
SIMPLE_HASHTABLE_SLOT_USERNAMES_CACHE *sl = simple_hashtable_get_slot_USERNAMES_CACHE(&user_cache.ht, hash, &uid, true);
CACHED_USERNAME *cu = SIMPLE_HASHTABLE_SLOT_DATA(sl);
if(!cu || (cu->version && version > cu->version)) {
internal_fatal(cu && cu->uid != uid, "invalid uid matched from cache");
if(cu)
string_freez(cu->username);
else
cu = callocz(1, sizeof(*cu));
cu->version = version;
cu->uid = uid;
cu->username = string_strdupz(username);
simple_hashtable_set_slot_USERNAMES_CACHE(&user_cache.ht, sl, hash, cu);
}
spinlock_unlock(&user_cache.spinlock);
}
CACHED_USERNAME cached_username_get_by_uid(uid_t uid) {
internal_fatal(!user_cache.initialized, "system-users cache needs to be initialized");
spinlock_lock(&user_cache.spinlock);
XXH64_hash_t hash = XXH3_64bits(&uid, sizeof(uid));
SIMPLE_HASHTABLE_SLOT_USERNAMES_CACHE *sl = simple_hashtable_get_slot_USERNAMES_CACHE(&user_cache.ht, hash, &uid, true);
CACHED_USERNAME *cu = SIMPLE_HASHTABLE_SLOT_DATA(sl);
if(!cu) {
cu = callocz(1, sizeof(*cu));
static char tmp[1024]; // we are inside a global spinlock - it is ok to be static
struct passwd pw, *result = NULL;
if (getpwuid_r(uid, &pw, tmp, sizeof(tmp), &result) != 0 || !result || !pw.pw_name || !(*pw.pw_name)) {
char name[UINT64_MAX_LENGTH];
print_uint64(name, uid);
cu->username = string_strdupz(name);
}
else
cu->username = string_strdupz(pw.pw_name);
cu->uid = uid;
simple_hashtable_set_slot_USERNAMES_CACHE(&user_cache.ht, sl, hash, cu);
}
internal_fatal(cu->uid != uid, "invalid uid matched from cache");
CACHED_USERNAME rc = {
.version = cu->version,
.uid = cu->uid,
.username = string_dup(cu->username),
};
spinlock_unlock(&user_cache.spinlock);
return rc;
}
void cached_username_release(CACHED_USERNAME cu) {
string_freez(cu.username);
}
void cached_usernames_init(void) {
if(user_cache.initialized) return;
user_cache.initialized = true;
spinlock_init(&user_cache.spinlock);
simple_hashtable_init_USERNAMES_CACHE(&user_cache.ht, 100);
}
void cached_usernames_destroy(void) {
if(!user_cache.initialized) return;
spinlock_lock(&user_cache.spinlock);
for(SIMPLE_HASHTABLE_SLOT_USERNAMES_CACHE *sl = simple_hashtable_first_read_only_USERNAMES_CACHE(&user_cache.ht);
sl;
sl = simple_hashtable_next_read_only_USERNAMES_CACHE(&user_cache.ht, sl)) {
CACHED_USERNAME *u = SIMPLE_HASHTABLE_SLOT_DATA(sl);
if(u) {
string_freez(u->username);
freez(u);
// simple_hashtable_del_slot_USERNAMES_CACHE(&uc.ht, sl);
}
}
simple_hashtable_destroy_USERNAMES_CACHE(&user_cache.ht);
user_cache.initialized = false;
spinlock_unlock(&user_cache.spinlock);
}
void cached_usernames_delete_old_versions(uint32_t version) {
if(!user_cache.initialized) return;
spinlock_lock(&user_cache.spinlock);
for(SIMPLE_HASHTABLE_SLOT_USERNAMES_CACHE *sl = simple_hashtable_first_read_only_USERNAMES_CACHE(&user_cache.ht);
sl;
sl = simple_hashtable_next_read_only_USERNAMES_CACHE(&user_cache.ht, sl)) {
CACHED_USERNAME *cu = SIMPLE_HASHTABLE_SLOT_DATA(sl);
if(cu && cu->version && cu->version < version) {
string_freez(cu->username);
freez(cu);
simple_hashtable_del_slot_USERNAMES_CACHE(&user_cache.ht, sl);
}
}
spinlock_unlock(&user_cache.spinlock);
}
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