From e2abcdca396661cbe0ae2ddb13d5c2b85682c13a Mon Sep 17 00:00:00 2001 From: Cem Keylan Date: Fri, 16 Oct 2020 17:41:25 +0300 Subject: initial commit --- lib/libc/gen/pwcache.c | 433 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 433 insertions(+) create mode 100644 lib/libc/gen/pwcache.c (limited to 'lib/libc/gen/pwcache.c') diff --git a/lib/libc/gen/pwcache.c b/lib/libc/gen/pwcache.c new file mode 100644 index 0000000..2f30f4b --- /dev/null +++ b/lib/libc/gen/pwcache.c @@ -0,0 +1,433 @@ +/* $OpenBSD: pwcache.c,v 1.15 2018/09/22 02:47:23 millert Exp $ */ + +/*- + * Copyright (c) 1992 Keith Muller. + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Keith Muller of the University of California, San Diego. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include + +#include +#include +#include +#include +#include +#include +#include + +/* + * Constants and data structures used to implement group and password file + * caches. Name lengths have been chosen to be as large as those supported + * by the passwd and group files as well as the standard archive formats. + * CACHE SIZES MUST BE PRIME + */ +#define UNMLEN 32 /* >= user name found in any protocol */ +#define GNMLEN 32 /* >= group name found in any protocol */ +#define UID_SZ 317 /* size of uid to user_name cache */ +#define UNM_SZ 317 /* size of user_name to uid cache */ +#define GID_SZ 251 /* size of gid to group_name cache */ +#define GNM_SZ 251 /* size of group_name to gid cache */ +#define VALID 1 /* entry and name are valid */ +#define INVALID 2 /* entry valid, name NOT valid */ + +/* + * Node structures used in the user, group, uid, and gid caches. + */ + +typedef struct uidc { + int valid; /* is this a valid or a miss entry */ + char name[UNMLEN]; /* uid name */ + uid_t uid; /* cached uid */ +} UIDC; + +typedef struct gidc { + int valid; /* is this a valid or a miss entry */ + char name[GNMLEN]; /* gid name */ + gid_t gid; /* cached gid */ +} GIDC; + +/* + * Routines that control user, group, uid and gid caches. + * Traditional passwd/group cache routines perform quite poorly with + * archives. The chances of hitting a valid lookup with an archive is quite a + * bit worse than with files already resident on the file system. These misses + * create a MAJOR performance cost. To adress this problem, these routines + * cache both hits and misses. + */ + +static UIDC **uidtb; /* uid to name cache */ +static GIDC **gidtb; /* gid to name cache */ +static UIDC **usrtb; /* user name to uid cache */ +static GIDC **grptb; /* group name to gid cache */ + +static u_int +st_hash(const char *name, size_t len, int tabsz) +{ + u_int key = 0; + + assert(name != NULL); + + while (len--) { + key += *name++; + key = (key << 8) | (key >> 24); + } + + return key % tabsz; +} + +/* + * uidtb_start + * creates an an empty uidtb + * Return: + * 0 if ok, -1 otherwise + */ +static int +uidtb_start(void) +{ + static int fail = 0; + + if (uidtb != NULL) + return 0; + if (fail) + return -1; + if ((uidtb = calloc(UID_SZ, sizeof(UIDC *))) == NULL) { + ++fail; + return -1; + } + return 0; +} + +/* + * gidtb_start + * creates an an empty gidtb + * Return: + * 0 if ok, -1 otherwise + */ +static int +gidtb_start(void) +{ + static int fail = 0; + + if (gidtb != NULL) + return 0; + if (fail) + return -1; + if ((gidtb = calloc(GID_SZ, sizeof(GIDC *))) == NULL) { + ++fail; + return -1; + } + return 0; +} + +/* + * usrtb_start + * creates an an empty usrtb + * Return: + * 0 if ok, -1 otherwise + */ +static int +usrtb_start(void) +{ + static int fail = 0; + + if (usrtb != NULL) + return 0; + if (fail) + return -1; + if ((usrtb = calloc(UNM_SZ, sizeof(UIDC *))) == NULL) { + ++fail; + return -1; + } + return 0; +} + +/* + * grptb_start + * creates an an empty grptb + * Return: + * 0 if ok, -1 otherwise + */ +static int +grptb_start(void) +{ + static int fail = 0; + + if (grptb != NULL) + return 0; + if (fail) + return -1; + if ((grptb = calloc(GNM_SZ, sizeof(GIDC *))) == NULL) { + ++fail; + return -1; + } + return 0; +} + +/* + * user_from_uid() + * caches the name (if any) for the uid. If noname clear, we always + * return the stored name (if valid or invalid match). + * We use a simple hash table. + * Return: + * Pointer to stored name (or a empty string) + */ +const char * +user_from_uid(uid_t uid, int noname) +{ + struct passwd *pw; + UIDC **pptr, *ptr = NULL; + + if ((uidtb != NULL) || (uidtb_start() == 0)) { + /* + * see if we have this uid cached + */ + pptr = uidtb + (uid % UID_SZ); + ptr = *pptr; + + if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) { + /* + * have an entry for this uid + */ + if (!noname || (ptr->valid == VALID)) + return ptr->name; + return NULL; + } + + if (ptr == NULL) + *pptr = ptr = malloc(sizeof(UIDC)); + } + + pw = getpwuid(uid); + if (pw == NULL) { + /* + * no match for this uid in the local password file + * a string that is the uid in numeric format + */ + if (ptr == NULL) + return NULL; + ptr->uid = uid; + (void)snprintf(ptr->name, UNMLEN, "%u", uid); + ptr->valid = INVALID; + if (noname) + return NULL; + } else { + /* + * there is an entry for this uid in the password file + */ + if (ptr == NULL) + return pw->pw_name; + ptr->uid = uid; + (void)strlcpy(ptr->name, pw->pw_name, sizeof(ptr->name)); + ptr->valid = VALID; + } + return ptr->name; +} + +/* + * group_from_gid() + * caches the name (if any) for the gid. If noname clear, we always + * return the stored name (if valid or invalid match). + * We use a simple hash table. + * Return: + * Pointer to stored name (or a empty string) + */ +const char * +group_from_gid(gid_t gid, int noname) +{ + struct group *gr; + GIDC **pptr, *ptr = NULL; + + if ((gidtb != NULL) || (gidtb_start() == 0)) { + /* + * see if we have this gid cached + */ + pptr = gidtb + (gid % GID_SZ); + ptr = *pptr; + + if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) { + /* + * have an entry for this gid + */ + if (!noname || (ptr->valid == VALID)) + return ptr->name; + return NULL; + } + + if (ptr == NULL) + *pptr = ptr = malloc(sizeof(GIDC)); + } + + gr = getgrgid(gid); + if (gr == NULL) { + /* + * no match for this gid in the local group file, put in + * a string that is the gid in numeric format + */ + if (ptr == NULL) + return NULL; + ptr->gid = gid; + (void)snprintf(ptr->name, GNMLEN, "%u", gid); + ptr->valid = INVALID; + if (noname) + return NULL; + } else { + /* + * there is an entry for this group in the group file + */ + if (ptr == NULL) + return gr->gr_name; + ptr->gid = gid; + (void)strlcpy(ptr->name, gr->gr_name, sizeof(ptr->name)); + ptr->valid = VALID; + } + return ptr->name; +} + +/* + * uid_from_user() + * caches the uid for a given user name. We use a simple hash table. + * Return: + * 0 if the user name is found (filling in uid), -1 otherwise + */ +int +uid_from_user(const char *name, uid_t *uid) +{ + struct passwd *pw; + UIDC **pptr, *ptr = NULL; + size_t namelen; + + /* + * return -1 for mangled names + */ + if (name == NULL || ((namelen = strlen(name)) == 0)) + return -1; + + if ((usrtb != NULL) || (usrtb_start() == 0)) { + /* + * look up in hash table, if found and valid return the uid, + * if found and invalid, return a -1 + */ + pptr = usrtb + st_hash(name, namelen, UNM_SZ); + ptr = *pptr; + + if ((ptr != NULL) && (ptr->valid > 0) && + strcmp(name, ptr->name) == 0) { + if (ptr->valid == INVALID) + return -1; + *uid = ptr->uid; + return 0; + } + + if (ptr == NULL) + *pptr = ptr = malloc(sizeof(UIDC)); + } + + /* + * no match, look it up, if no match store it as an invalid entry, + * or store the matching uid + */ + pw = getpwnam(name); + if (ptr == NULL) { + if (pw == NULL) + return -1; + *uid = pw->pw_uid; + return 0; + } + (void)strlcpy(ptr->name, name, sizeof(ptr->name)); + if (pw == NULL) { + ptr->valid = INVALID; + return -1; + } + ptr->valid = VALID; + *uid = ptr->uid = pw->pw_uid; + return 0; +} + +/* + * gid_from_group() + * caches the gid for a given group name. We use a simple hash table. + * Return: + * 0 if the group name is found (filling in gid), -1 otherwise + */ +int +gid_from_group(const char *name, gid_t *gid) +{ + struct group *gr; + GIDC **pptr, *ptr = NULL; + size_t namelen; + + /* + * return -1 for mangled names + */ + if (name == NULL || ((namelen = strlen(name)) == 0)) + return -1; + + if ((grptb != NULL) || (grptb_start() == 0)) { + /* + * look up in hash table, if found and valid return the uid, + * if found and invalid, return a -1 + */ + pptr = grptb + st_hash(name, namelen, GID_SZ); + ptr = *pptr; + + if ((ptr != NULL) && (ptr->valid > 0) && + strcmp(name, ptr->name) == 0) { + if (ptr->valid == INVALID) + return -1; + *gid = ptr->gid; + return 0; + } + + if (ptr == NULL) + *pptr = ptr = malloc(sizeof(GIDC)); + } + + /* + * no match, look it up, if no match store it as an invalid entry, + * or store the matching gid + */ + gr = getgrnam(name); + if (ptr == NULL) { + if (gr == NULL) + return -1; + *gid = gr->gr_gid; + return 0; + } + + (void)strlcpy(ptr->name, name, sizeof(ptr->name)); + if (gr == NULL) { + ptr->valid = INVALID; + return -1; + } + ptr->valid = VALID; + *gid = ptr->gid = gr->gr_gid; + return 0; +} -- cgit v1.2.3