-/* $OpenBSD: pwcache.c,v 1.13 2015/11/25 23:16:01 jcs Exp $ */
-/*
- * Copyright (c) 1989, 1993
+/* $OpenBSD: pwcache.c,v 1.14 2018/09/13 12:31:15 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:
#include <sys/types.h>
+#include <assert.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
+
+/*
+ * 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;
-#define NCACHE 16 /* power of 2 */
-#define NLINES 4 /* associativity */
-#define MASK (NCACHE - 1) /* bits to store with */
-#define IDX(x, i) ((x & MASK) + i * NCACHE)
+ if (grptb != NULL)
+ return 0;
+ if (fail)
+ return -1;
+ if ((grptb = calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
+ ++fail;
+ return -1;
+ }
+ return 0;
+}
-char *
-user_from_uid(uid_t uid, int nouser)
+/*
+ * 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)
{
- static struct ncache {
- uid_t uid;
- short noname;
- char name[_PW_NAME_LEN + 1];
- } c_uid[NLINES * NCACHE];
+ struct passwd pwstore, *pw = NULL;
char pwbuf[_PW_BUF_LEN];
- struct passwd pwstore, *pw;
- struct ncache *cp;
- unsigned int i;
-
- for (i = 0; i < NLINES; i++) {
- cp = &c_uid[IDX(uid, i)];
- if (!*cp->name) {
-fillit:
- cp->uid = uid;
- pw = NULL;
- getpwuid_r(uid, &pwstore, pwbuf, sizeof(pwbuf), &pw);
- if (pw == NULL) {
- snprintf(cp->name, sizeof(cp->name), "%u", uid);
- cp->noname = 1;
- } else {
- strlcpy(cp->name, pw->pw_name, sizeof(cp->name));
- }
- }
- if (cp->uid == uid) {
- if (nouser && cp->noname)
- return NULL;
- return cp->name;
+ 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));
}
- /* move everybody down a slot */
- for (i = 0; i < NLINES - 1; i++) {
- struct ncache *next;
- cp = &c_uid[IDX(uid, i)];
- next = &c_uid[IDX(uid, i + 1)];
- memcpy(next, cp, sizeof(*cp));
+ getpwuid_r(uid, &pwstore, pwbuf, sizeof(pwbuf), &pw);
+ 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;
}
- cp = &c_uid[IDX(uid, 0)];
- goto fillit;
+ return ptr->name;
}
-char *
-group_from_gid(gid_t gid, int nogroup)
+/*
+ * 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)
{
- static struct ncache {
- gid_t gid;
- short noname;
- char name[_PW_NAME_LEN + 1];
- } c_gid[NLINES * NCACHE];
+ struct group grstore, *gr = NULL;
char grbuf[_GR_BUF_LEN];
- struct group grstore, *gr;
- struct ncache *cp;
- unsigned int i;
-
- for (i = 0; i < NLINES; i++) {
- cp = &c_gid[IDX(gid, i)];
- if (!*cp->name) {
-fillit:
- cp->gid = gid;
- gr = NULL;
- getgrgid_r(gid, &grstore, grbuf, sizeof(grbuf), &gr);
- if (gr == NULL) {
- snprintf(cp->name, sizeof(cp->name), "%u", gid);
- cp->noname = 1;
- } else {
- strlcpy(cp->name, gr->gr_name, sizeof(cp->name));
- }
+ 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 (cp->gid == gid) {
- if (nogroup && cp->noname)
- return NULL;
- return cp->name;
+
+ if (ptr == NULL)
+ *pptr = ptr = malloc(sizeof(GIDC));
+ }
+
+ getgrgid_r(gid, &grstore, grbuf, sizeof(grbuf), &gr);
+ 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
+ * the uid (if any) for a user name, or a -1 if no match can be found
+ */
+int
+uid_from_user(const char *name, uid_t *uid)
+{
+ struct passwd pwstore, *pw = NULL;
+ char pwbuf[_PW_BUF_LEN];
+ 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
+ */
+ getpwnam_r(name, &pwstore, pwbuf, sizeof(pwbuf), &pw);
+ 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
+ * the gid (if any) for a group name, or a -1 if no match can be found
+ */
+int
+gid_from_group(const char *name, gid_t *gid)
+{
+ struct group grstore, *gr = NULL;
+ char grbuf[_GR_BUF_LEN];
+ 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
+ */
+ getgrnam_r(name, &grstore, grbuf, sizeof(grbuf), &gr);
+ if (ptr == NULL) {
+ if (gr == NULL)
+ return -1;
+ *gid = gr->gr_gid;
+ return 0;
}
- /* move everybody down a slot */
- for (i = 0; i < NLINES - 1; i++) {
- struct ncache *next;
- cp = &c_gid[IDX(gid, i)];
- next = &c_gid[IDX(gid, i + 1)];
- memcpy(next, cp, sizeof(*cp));
+ (void)strlcpy(ptr->name, name, sizeof(ptr->name));
+ if (gr == NULL) {
+ ptr->valid = INVALID;
+ return -1;
}
- cp = &c_gid[IDX(gid, 0)];
- goto fillit;
+ ptr->valid = VALID;
+ *gid = ptr->gid = gr->gr_gid;
+ return 0;
}
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