--- /dev/null
+.\" $OpenBSD: pwcache.3,v 1.15 2018/09/13 16:50:54 jmc Exp $
+.\"
+.\" Copyright (c) 1989, 1991, 1993
+.\" The Regents of the University of California. All rights reserved.
+.\"
+.\" 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.
+.\"
+.Dd $Mdocdate: September 13 2018 $
+.Dt USER_FROM_UID 3
+.Os
+.Sh NAME
+.Nm user_from_uid ,
+.Nm uid_from_user ,
+.Nm group_from_gid ,
+.Nm gid_from_group
+.Nd cache password and group entries
+.Sh LIBRARY
+.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
+.ds doc-str-Lb-libbsd \*[str-Lb-libbsd]
+.Lb libbsd
+.Sh SYNOPSIS
+.In pwd.h
+(See
+.Xr libbsd 7
+for include usage.)
+.Ft int
+.Fn uid_from_user "const char *name" "uid_t *uid"
+.Ft const char *
+.Fn user_from_uid "uid_t uid" "int nouser"
+.In grp.h
+.Ft int
+.Fn gid_from_group "const char *name" "gid_t *gid"
+.Ft const char *
+.Fn group_from_gid "gid_t gid" "int nogroup"
+.Sh DESCRIPTION
+The
+.Fn user_from_uid
+function returns the user name associated with the argument
+.Fa uid .
+The user name is cached so that multiple calls with the same
+.Fa uid
+do not require additional calls to
+.Xr getpwuid 3 .
+If there is no user associated with the
+.Fa uid ,
+a pointer is returned
+to a string representation of the
+.Fa uid ,
+unless the argument
+.Fa nouser
+is non-zero, in which case a null pointer is returned.
+.Pp
+The
+.Fn uid_from_user
+function returns the user ID associated with the argument
+.Fa name .
+The user ID is cached so that multiple calls with the same
+.Fa name
+do not require additional calls to
+.Xr getpwnam 3 .
+If there is no user ID associated with the
+.Fa name ,
+the
+.Fn uid_from_user
+function returns -1;
+otherwise it stores the user ID at the location pointed to by
+.Fa uid
+and returns 0.
+.Pp
+The
+.Fn group_from_gid
+function returns the group name associated with the argument
+.Fa gid .
+The group name is cached so that multiple calls with the same
+.Fa gid
+do not require additional calls to
+.Xr getgrgid 3 .
+If there is no group associated with the
+.Fa gid ,
+a pointer is returned
+to a string representation of the
+.Fa gid ,
+unless the argument
+.Fa nogroup
+is non-zero, in which case a null pointer is returned.
+.Pp
+The
+.Fn gid_from_group
+function returns the group ID associated with the argument
+.Fa name .
+The group ID is cached so that multiple calls with the same
+.Fa name
+do not require additional calls to
+.Xr getgrnam 3 .
+If there is no group ID associated with the
+.Fa name ,
+the
+.Fn gid_from_group
+function returns -1;
+otherwise it stores the group ID at the location pointed to by
+.Fa gid
+and returns 0.
+.Sh SEE ALSO
+.Xr getgrgid 3 ,
+.Xr getpwuid 3
+.Sh HISTORY
+The
+.Fn user_from_uid
+and
+.Fn group_from_gid
+functions first appeared in
+.Bx 4.4 .
+.Pp
+The
+.Fn uid_from_user
+and
+.Fn gid_from_group
+functions were ported from
+.Nx
+and first appeared in
+.Ox 6.4 .
--- /dev/null
+/* $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 <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;
+
+ 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 pwstore, *pw = NULL;
+ char pwbuf[_PW_BUF_LEN];
+ 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));
+ }
+
+ 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;
+ }
+ 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 grstore, *gr = NULL;
+ char grbuf[_GR_BUF_LEN];
+ 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));
+ }
+
+ 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:
+ * 0 if the user name is found (filling in uid), -1 otherwise
+ */
+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:
+ * 0 if the group name is found (filling in gid), -1 otherwise
+ */
+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;
+ }
+
+ (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;
+}
projects / thirdparty / libbsd.git / commitdiff
