c50f370f9
Denis Vlasenko
2006-11-24
Subject
tar: cache [ug]id->username/groupname mappings. Cuts down amount of open/read/close of /etc/passwd and /etc/group dramatically (we were rereading those for each untarred file!!!)
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Commit Diff GitHub →
archival/tar.c+3 -6
| @@ -211,12 +211,9 @@ static int writeTarHeader(struct TarBallInfo *tbInfo, | |
| putOctal(header.mtime, sizeof(header.mtime), statbuf->st_mtime); | |
| strcpy(header.magic, "ustar "); | |
| - | /* Enter the user and group names (default to root if it fails) */ |
| - | //cache!!! |
| - | if (bb_getpwuid(header.uname, statbuf->st_uid, sizeof(header.uname)) == NULL) |
| - | strcpy(header.uname, "root"); |
| - | if (bb_getgrgid(header.gname, statbuf->st_gid, sizeof(header.gname)) == NULL) |
| - | strcpy(header.gname, "root"); |
| + | /* Enter the user and group names */ |
| + | safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname)); |
| + | safe_strncpy(header.gname, get_cached_groupname(statbuf->st_gid), sizeof(header.gname)); |
| if (tbInfo->hlInfo) { | |
| /* This is a hard link */ | |
include/libbb.h+1 -0
| @@ -567,6 +567,7 @@ pid_t *find_pid_by_name(const char* procName); | |
| pid_t *pidlist_reverse(pid_t *pidList); | |
| void clear_username_cache(void); | |
| const char* get_cached_username(uid_t uid); | |
| + | const char* get_cached_groupname(gid_t gid); |
| extern const char bb_uuenc_tbl_base64[]; | |
libbb/procps.c+48 -18
| @@ -11,32 +11,62 @@ | |
| #include "libbb.h" | |
| - | typedef struct { |
| - | uid_t uid; |
| - | char username[12]; |
| - | } user_map_t; |
| + | typedef struct unsigned_to_name_map_t { |
| + | unsigned id; |
| + | char name[12]; |
| + | } unsigned_to_name_map_t; |
| - | static user_map_t *username_cache; |
| - | static int username_cache_size; |
| + | typedef struct cache_t { |
| + | unsigned_to_name_map_t *cache; |
| + | int size; |
| + | } cache_t; |
| + | static cache_t username, groupname; |
| + | |
| + | static void clear_cache(cache_t *cp) |
| + | { |
| + | free(cp->cache); |
| + | cp->cache = NULL; |
| + | cp->size = 0; |
| + | } |
| void clear_username_cache(void) | |
| { | |
| - | free(username_cache); |
| - | username_cache = NULL; |
| - | username_cache_size = 0; |
| + | clear_cache(&username); |
| + | clear_cache(&groupname); |
| } | |
| - | const char* get_cached_username(uid_t uid) |
| + | /* Returns -N-1 if not found. */ |
| + | /* cp->cache[N] is allocated and must be filled in this case */ |
| + | static int get_cached(cache_t *cp, unsigned id) |
| { | |
| int i; | |
| - | for (i = 0; i < username_cache_size; i++) |
| - | if (username_cache[i].uid == uid) |
| - | return username_cache[i].username; |
| - | i = username_cache_size++; |
| - | username_cache = xrealloc(username_cache, username_cache_size * sizeof(*username_cache)); |
| - | username_cache[i].uid = uid; |
| - | bb_getpwuid(username_cache[i].username, uid, sizeof(username_cache[i].username)); |
| - | return username_cache[i].username; |
| + | for (i = 0; i < cp->size; i++) |
| + | if (cp->cache[i].id == id) |
| + | return i; |
| + | i = cp->size++; |
| + | cp->cache = xrealloc(cp->cache, cp->size * sizeof(*cp->cache)); |
| + | cp->cache[i++].id = id; |
| + | return -i; |
| + | } |
| + | const char* get_cached_username(uid_t uid) |
| + | { |
| + | int i = get_cached(&username, uid); |
| + | if (i < 0) { |
| + | i = -i - 1; |
| + | bb_getpwuid(username.cache[i].name, uid, |
| + | sizeof(username.cache[i].name)); |
| + | } |
| + | return username.cache[i].name; |
| + | } |
| + | const char* get_cached_groupname(uid_t uid) |
| + | { |
| + | int i = get_cached(&groupname, uid); |
| + | if (i < 0) { |
| + | i = -i - 1; |
| + | bb_getgrgid(groupname.cache[i].name, uid, |
| + | sizeof(groupname.cache[i].name)); |
| + | } |
| + | return username.cache[i].name; |
| } | |