port/gen/getgrnam_r.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "lint.h"
#include <mtlib.h>
#include <sys/types.h>
#include <grp.h>
#include <memory.h>
#include <deflt.h>
#include <nsswitch.h>
#include <nss_dbdefs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <synch.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <errno.h>

extern int _getgroupsbymember(const char *, gid_t[], int, int);
int str2group(const char *, int, void *, char *, int);

static DEFINE_NSS_DB_ROOT(db_root);
static DEFINE_NSS_GETENT(context);

#define USE_NETID_STR   "NETID_AUTHORITATIVE=TRUE"

void
_nss_initf_group(nss_db_params_t *p)
{
    p->name = NSS_DBNAM_GROUP;
    p->default_config = NSS_DEFCONF_GROUP;
}

#include <getxby_door.h>
#include <sys/door.h>

struct group *
_uncached_getgrnam_r(const char *name, struct group *result, char *buffer,
    int buflen);

struct group *
_uncached_getgrgid_r(gid_t gid, struct group *result, char *buffer, int buflen);

/*
 * POSIX.1c Draft-6 version of the function getgrnam_r.
 * It was implemented by Solaris 2.3.
 */
struct group *
getgrnam_r(const char *name, struct group *result, char *buffer, int buflen)
{
    nss_XbyY_args_t arg;

    if (name == (const char *)NULL) {
        errno = ERANGE;
        return (NULL);
    }
    NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
    arg.key.name = name;
    (void) nss_search(&db_root, _nss_initf_group,
        NSS_DBOP_GROUP_BYNAME, &arg);
    return ((struct group *)NSS_XbyY_FINI(&arg));
}

/*
 * POSIX.1c Draft-6 version of the function getgrgid_r.
 * It was implemented by Solaris 2.3.
 */
struct group *
getgrgid_r(gid_t gid, struct group *result, char *buffer, int buflen)
{
    nss_XbyY_args_t arg;

    NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
    arg.key.gid = gid;
    (void) nss_search(&db_root, _nss_initf_group,
        NSS_DBOP_GROUP_BYGID, &arg);
    return ((struct group *)NSS_XbyY_FINI(&arg));
}

struct group *
_uncached_getgrgid_r(gid_t gid, struct group *result, char *buffer,
    int buflen)
{
    nss_XbyY_args_t arg;

    NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
    arg.key.gid = gid;
    (void) nss_search(&db_root, _nss_initf_group,
        NSS_DBOP_GROUP_BYGID, &arg);
    return ((struct group *)NSS_XbyY_FINI(&arg));
}

/*
 * POSIX.1c standard version of the function getgrgid_r.
 * User gets it via static getgrgid_r from the header file.
 */
int
__posix_getgrgid_r(gid_t gid, struct group *grp, char *buffer,
    size_t bufsize, struct group **result)
{
    int nerrno = 0;
    int oerrno = errno;

    errno = 0;
    if ((*result = getgrgid_r(gid, grp, buffer, (uintptr_t)bufsize))
        == NULL) {
            nerrno = errno;
    }
    errno = oerrno;
    return (nerrno);
}

struct group *
_uncached_getgrnam_r(const char *name, struct group *result, char *buffer,
    int buflen)
{
    nss_XbyY_args_t arg;

    NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
    arg.key.name = name;
    (void) nss_search(&db_root, _nss_initf_group,
        NSS_DBOP_GROUP_BYNAME, &arg);
    return ((struct group *)NSS_XbyY_FINI(&arg));
}

/*
 * POSIX.1c standard version of the function getgrnam_r.
 * User gets it via static getgrnam_r from the header file.
 */
int
__posix_getgrnam_r(const char *name, struct group *grp, char *buffer,
    size_t bufsize, struct group **result)
{
    int nerrno = 0;
    int oerrno = errno;

    if ((*result = getgrnam_r(name, grp, buffer, (uintptr_t)bufsize))
        == NULL) {
            nerrno = errno;
    }
    errno = oerrno;
    return (nerrno);
}

void
setgrent(void)
{
    nss_setent(&db_root, _nss_initf_group, &context);
}

void
endgrent(void)
{
    nss_endent(&db_root, _nss_initf_group, &context);
    nss_delete(&db_root);
}

struct group *
getgrent_r(struct group *result, char *buffer, int buflen)
{
    nss_XbyY_args_t arg;
    char        *nam;

    /* In getXXent_r(), protect the unsuspecting caller from +/- entries */

    do {
        NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
        /* No key to fill in */
        (void) nss_getent(&db_root, _nss_initf_group, &context, &arg);
    } while (arg.returnval != 0 &&
        (nam = ((struct group *)arg.returnval)->gr_name) != 0 &&
        (*nam == '+' || *nam == '-'));

    return ((struct group *)NSS_XbyY_FINI(&arg));
}

struct group *
fgetgrent_r(FILE *f, struct group *result, char *buffer, int buflen)
{
    extern void _nss_XbyY_fgets(FILE *, nss_XbyY_args_t *);
    nss_XbyY_args_t arg;

    /* ... but in fgetXXent_r, the caller deserves any +/- entry he gets */

    /* No key to fill in */
    NSS_XbyY_INIT(&arg, result, buffer, buflen, str2group);
    _nss_XbyY_fgets(f, &arg);
    return ((struct group *)NSS_XbyY_FINI(&arg));
}

/*
 * _getgroupsbymember(uname, gid_array, maxgids, numgids):
 *  Private interface for initgroups().  It returns the group ids of
 *  groups of which the specified user is a member.
 *
 * Arguments:
 *   username   Username of the putative member
 *   gid_array  Space in which to return the gids.  The first [numgids]
 *      elements are assumed to already contain valid gids.
 *   maxgids    Maximum number of elements in gid_array.
 *   numgids    Number of elements (normally 0 or 1) that already contain
 *      valid gids.
 * Return value:
 *   number of valid gids in gid_array (may be zero)
 *  or
 *   -1 (and errno set appropriately) on errors (none currently defined)
 *
 * NSS2 Consistency enhancements:
 *   The "files normal" format between an application and nscd for the
 *   NSS_DBOP_GROUP_BYMEMBER nss_search operation is defined to be a
 *   processed array of numgids [up to maxgids] gid_t values.  gid_t
 *   values in the array are unique.
 */

extern nss_status_t process_cstr(const char *, int, struct nss_groupsbymem *);

int
_getgroupsbymember(const char *username, gid_t gid_array[],
    int maxgids, int numgids)
{
    struct nss_groupsbymem  arg;
    void    *defp;

    arg.username    = username;
    arg.gid_array   = gid_array;
    arg.maxgids = maxgids;
    arg.numgids = numgids;
    /*
     * In backwards compatibility mode, use the old str2group &
     * process_cstr interfaces.  Ditto within nscd processing.
     */
    arg.str2ent = str2group;
    arg.process_cstr = process_cstr;

    /*
     * The old value being provided here was 0, ie do the quick
     * way.  Given that this was never actually used under NIS
     * and had the wrong (now corrected) meaning for NIS+ we need
     * to change the default to be 1 (TRUE) as we now need the
     * admin to decided to use netid, setting NETID_AUTHORITATIVE
     * in /etc/default/nss to TRUE gets us a value of 0 for
     * force_slow_way - don't you just love double negatives ;-)
     *
     * We need to do this to preserve the behaviour seen when the
     * admin makes no changes.
     */
    arg.force_slow_way = 1;

    if ((defp = defopen_r(__NSW_DEFAULT_FILE)) != NULL) {
        if (defread_r(USE_NETID_STR, defp) != NULL)
            arg.force_slow_way = 0;
        defclose_r(defp);
    }

    (void) nss_search(&db_root, _nss_initf_group,
        NSS_DBOP_GROUP_BYMEMBER, &arg);

    return (arg.numgids);
}


static char *
gettok(char **nextpp, char sep)
{
    char    *p = *nextpp;
    char    *q = p;
    char    c;

    if (p == 0)
        return (0);

    while ((c = *q) != '\0' && c != sep)
        q++;

    if (c == '\0')
        *nextpp = 0;
    else {
        *q++ = '\0';
        *nextpp = q;
    }
    return (p);
}

/*
 * Return values: 0 = success, 1 = parse error, 2 = erange ...
 * The structure pointer passed in is a structure in the caller's space
 * wherein the field pointers would be set to areas in the buffer if
 * need be. instring and buffer should be separate areas.
 */
int
str2group(const char *instr, int lenstr, void *ent, char *buffer, int buflen)
{
    struct group        *group  = (struct group *)ent;
    char            *p, *next;
    int         black_magic;    /* "+" or "-" entry */
    char            **memlist, **limit;
    ulong_t         tmp;

    if (lenstr + 1 > buflen)
        return (NSS_STR_PARSE_ERANGE);

    /*
     * We copy the input string into the output buffer and
     * operate on it in place.
     */
    if (instr != buffer) {
        /* Overlapping buffer copies are OK */
        (void) memmove(buffer, instr, lenstr);
        buffer[lenstr] = '\0';
    }

    /* quick exit do not entry fill if not needed */
    if (ent == (void *)NULL)
        return (NSS_STR_PARSE_SUCCESS);

    next = buffer;

    /*
     * Parsers for passwd and group have always been pretty rigid;
     * we wouldn't want to buck a Unix tradition
     */

    group->gr_name = p = gettok(&next, ':');
    if (*p == '\0') {
        /* Empty group-name;  not allowed */
        return (NSS_STR_PARSE_PARSE);
    }

    /* Always return at least an empty gr_mem list */
    memlist = (char **)ROUND_UP(buffer + lenstr + 1, sizeof (char *));
    limit   = (char **)ROUND_DOWN(buffer + buflen, sizeof (char *));
    *memlist = 0;
    group->gr_mem = memlist;

    black_magic = (*p == '+' || *p == '-');
    if (black_magic) {
        /* Then the rest of the group entry is optional */
        group->gr_passwd = 0;
        group->gr_gid = 0;
    }

    group->gr_passwd = p = gettok(&next, ':');
    if (p == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }

    p = next;                   /* gid */
    if (p == 0 || *p == '\0') {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    if (!black_magic) {
        errno = 0;
        tmp = strtoul(p, &next, 10);
        if (next == p || errno != 0) {
            /* gid field should be nonempty */
            /* also check errno from strtoul */
            return (NSS_STR_PARSE_PARSE);
        }
        if (tmp >= UINT32_MAX)
            group->gr_gid = GID_NOBODY;
        else
            group->gr_gid = (gid_t)tmp;
    }
    if (*next++ != ':') {
        /* Parse error, even for a '+' entry (which should have */
        /*   an empty gid field, since it's always overridden)  */
        return (NSS_STR_PARSE_PARSE);
    }

    /* === Could check and complain if there are any extra colons */
    while (memlist < limit) {
        p = gettok(&next, ',');
        if (p == 0 || *p == '\0') {
            *memlist = 0;
            /* Successfully parsed and stored */
            return (NSS_STR_PARSE_SUCCESS);
        }
        *memlist++ = p;
    }
    /* Out of space;  error even for black_magic */
    return (NSS_STR_PARSE_ERANGE);
}

nss_status_t
process_cstr(const char *instr, int instr_len, struct nss_groupsbymem *gbm)
{
    /*
     * It's possible to do a much less inefficient version of this by
     * selectively duplicating code from str2group().  For now,
     * however, we'll take the easy way out and implement this on
     * top of str2group().
     */

    const char      *username = gbm->username;
    nss_XbyY_buf_t      *buf;
    struct group        *grp;
    char            **memp;
    char            *mem;
    int parsestat;

    buf = _nss_XbyY_buf_alloc(sizeof (struct group), NSS_BUFLEN_GROUP);
    if (buf == 0)
        return (NSS_UNAVAIL);

    grp = (struct group *)buf->result;

    parsestat = (*gbm->str2ent)(instr, instr_len,
        grp, buf->buffer, buf->buflen);

    if (parsestat != NSS_STR_PARSE_SUCCESS) {
        _nss_XbyY_buf_free(buf);
        return (NSS_NOTFOUND);  /* === ? */
    }

    if (grp->gr_mem) {
        for (memp = grp->gr_mem; (memp) && ((mem = *memp) != 0);
            memp++) {
            if (strcmp(mem, username) == 0) {
                gid_t   gid     = grp->gr_gid;
                gid_t   *gidp   = gbm->gid_array;
                int numgids = gbm->numgids;
                int i;

                _nss_XbyY_buf_free(buf);

                for (i = 0; i < numgids && *gidp != gid; i++,
                    gidp++) {
                    ;
                }
                if (i >= numgids) {
                    if (i >= gbm->maxgids) {
                    /* Filled the array;  stop searching */
                        return (NSS_SUCCESS);
                    }
                    *gidp = gid;
                    gbm->numgids = numgids + 1;
                }
                return (NSS_NOTFOUND);  /* Explained in   */
                            /* <nss_dbdefs.h> */
            }
        }
    }
    _nss_XbyY_buf_free(buf);
    return (NSS_NOTFOUND);
}