files/common/getexecattr.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 (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <stdlib.h>
#include "files_common.h"
#include <time.h>
#include <exec_attr.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <ctype.h>
#include <synch.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>

/*
 * files/getexecattr.c -- "files" backend for nsswitch "exec_attr" database
 *
 * _execattr_files_read_line and _execattr_files_XY_all code based on
 * nss_files_read_line and nss_files_XY_all respectively, from files_common.c
 */


/* externs from libnsl */
extern int _doexeclist(nss_XbyY_args_t *);
extern int _readbufline(char *, int, char *, int, int *);
extern char *_exec_wild_id(char *, const char *);
extern void _exec_cleanup(nss_status_t, nss_XbyY_args_t *);


/*
 * check_match: returns 1 if matching entry found, else returns 0.
 */
static int
check_match(nss_XbyY_args_t *argp, const char *line, int linelen)
{
    const char  *limit, *linep, *keyp;
    _priv_execattr  *_priv_exec = (_priv_execattr *)(argp->key.attrp);
    const char  *exec_field[6];
    int     i;

    exec_field[0] = _priv_exec->name;   /* name */
    exec_field[1] = _priv_exec->policy; /* policy */
    exec_field[2] = _priv_exec->type;   /* type */
    exec_field[3] = NULL;           /* res1 */
    exec_field[4] = NULL;           /* res2 */
    exec_field[5] = _priv_exec->id;     /* id */
    /* No need to check attr field */

    linep = line;
    limit = line + linelen;

    for (i = 0; i < 6; i++) {
        keyp = exec_field[i];
        if (keyp) {
            /* compare field */
            while (*keyp && linep < limit &&
                *linep != ':' && *keyp == *linep) {
                keyp++;
                linep++;
            }
            if (*keyp || linep == limit || *linep != ':')
                return (0);
        } else {
            /* skip field */
            while (linep < limit && *linep != ':')
                linep++;
        }
        linep++;
    }
    return (1);
}


static nss_status_t
_exec_files_XY_all(files_backend_ptr_t be,
    nss_XbyY_args_t *argp,
    int getby_flag)
{
    int     parse_stat = 0;
    int     lastlen = 0;
    int     exec_fd = 0;
    int     f_size = 0;
    time_t      f_time = 0;
    static time_t   read_time = 0;
    char        *first;
    char        *last;
    static char *f_buf = NULL;
    struct stat f_stat;
    nss_status_t    res = NSS_NOTFOUND;
    _priv_execattr  *_priv_exec = (_priv_execattr *)(argp->key.attrp);
    static rwlock_t exec_lock;

    if (((be->buf == NULL) &&
        ((be->buf = (char *)calloc(1, be->minbuf)) == NULL)) ||
        (be->filename == NULL) ||
        (rw_rdlock(&exec_lock) != 0)) {
        return (NSS_UNAVAIL);
    }

    /*
     * check the size and the time stamp on the file
     */
    if (stat(be->filename, &f_stat) != 0) {
        (void) _nss_files_endent(be, 0);
        (void) rw_unlock(&exec_lock);
        return (NSS_UNAVAIL);
    }

    f_size = f_stat.st_size;
    f_time = f_stat.st_mtime;

    while (f_time > read_time || f_buf == NULL) {
        /*
         * file has been modified since we last read it
         * or we never read it or memory allocation
         * failed before.
         * read it into the buffer with rw lock.
         */
        (void) rw_unlock(&exec_lock);
        if (rw_wrlock(&exec_lock) != 0) {
            (void) _nss_files_endent(be, 0);
            return (NSS_UNAVAIL);
        }
        if ((be->f = fopen(be->filename, "rF")) == 0) {
            (void) _nss_files_endent(be, 0);
            (void) rw_unlock(&exec_lock);
            return (NSS_UNAVAIL);
        }
        exec_fd = fileno(be->f);
        if (f_buf != NULL)
            free(f_buf);
        if ((f_buf = malloc(f_size)) == NULL) {
            (void) _nss_files_endent(be, 0);
            (void) rw_unlock(&exec_lock);
            return (NSS_UNAVAIL);
        }
        if (read(exec_fd, f_buf, f_size) < f_size) {
            free(f_buf);
            (void) _nss_files_endent(be, 0);
            (void) rw_unlock(&exec_lock);
            return (NSS_UNAVAIL);
        }
        read_time = f_time;
        (void) rw_unlock(&exec_lock);
        /*
         * verify that the file did not change after
         * we read it.
         */
        if (rw_rdlock(&exec_lock) != 0) {
            free(f_buf);
            (void) _nss_files_endent(be, 0);
            return (NSS_UNAVAIL);
        }
        if (stat(be->filename, &f_stat) != 0) {
            free(f_buf);
            (void) _nss_files_endent(be, 0);
            (void) rw_unlock(&exec_lock);
            return (NSS_UNAVAIL);
        }
        f_size = f_stat.st_size;
        f_time = f_stat.st_mtime;
    }

    res = NSS_NOTFOUND;
    /*CONSTCOND*/
    while (1) {
        int linelen = 0;
        char    *instr = be->buf;

        linelen = _readbufline(f_buf, f_size, instr, be->minbuf,
            &lastlen);
        if (linelen < 0) {
            /* End of file */
            break;
        }

        /*
         * If the entry doesn't contain the filter string then
         * it can't be the entry we want, so don't bother looking
         * more closely at it.
         */
        switch (getby_flag) {
        case NSS_DBOP_EXECATTR_BYNAME:
            if (strstr(instr, _priv_exec->name) == NULL)
                continue;
            break;
        case NSS_DBOP_EXECATTR_BYID:
            if (strstr(instr, _priv_exec->id) == NULL)
                continue;
            break;
        case NSS_DBOP_EXECATTR_BYNAMEID:
            if ((strstr(instr, _priv_exec->name) == NULL) ||
                (strstr(instr, _priv_exec->id) == NULL))
                continue;
            break;
        default:
            break;
        }
        if (((_priv_exec->policy != NULL) &&
            (strstr(instr, _priv_exec->policy) == NULL)) ||
            ((_priv_exec->type != NULL) &&
            (strstr(instr, _priv_exec->type) == NULL)))
                continue;

        /*
         * Get rid of white spaces, comments etc.
         */
        if ((last = strchr(instr, '#')) == NULL)
            last = instr + linelen;
        *last-- = '\0'; /* Nuke '\n' or #comment */
        /*
         * Skip leading whitespace.  Normally there isn't any,
         * so it's not worth calling strspn().
         */
        for (first = instr; isspace(*first); first++)
            ;
        if (*first == '\0')
            continue;
        /*
         * Found something non-blank on the line.  Skip back
         * over any trailing whitespace;  since we know there's
         * non-whitespace earlier in the line, checking for
         * termination is easy.
         */
        while (isspace(*last))
            --last;
        linelen = last - first + 1;
        if (first != instr)
            instr = first;

        /* Check the entry */
        argp->returnval = NULL;
        argp->returnlen = 0;
        if (check_match(argp, instr, linelen) == 0)
            continue;

        /* Marshall the data */
        parse_stat = (*argp->str2ent)(instr, linelen, argp->buf.result,
            argp->buf.buffer, argp->buf.buflen);
        if (parse_stat == NSS_STR_PARSE_SUCCESS) {
            argp->returnval = (argp->buf.result != NULL)?
                argp->buf.result : argp->buf.buffer;
            argp->returnlen = linelen;
            res = NSS_SUCCESS;
            if (IS_GET_ONE(_priv_exec->search_flag)) {
                break;
            } else if (_doexeclist(argp) == 0) {
                res = NSS_UNAVAIL;
                break;
            }
        } else if (parse_stat == NSS_STR_PARSE_ERANGE) {
            argp->erange = 1;
            break;
        } /* else if (parse_stat == NSS_STR_PARSE_PARSE) don't care ! */
    }

    (void) _nss_files_endent(be, 0);
    (void) rw_unlock(&exec_lock);

    return (res);
}


/*
 * If search for exact match for id failed, get_wild checks if we have
 * a wild-card entry for that id.
 */
static nss_status_t
get_wild(files_backend_ptr_t be, nss_XbyY_args_t *argp, int getby_flag)
{
    const char  *orig_id = NULL;
    char        *old_id = NULL;
    char        *wild_id = NULL;
    nss_status_t    res = NSS_NOTFOUND;
    _priv_execattr  *_priv_exec = (_priv_execattr *)(argp->key.attrp);

    orig_id = _priv_exec->id;
    old_id = strdup(_priv_exec->id);
    wild_id = old_id;
    while ((wild_id = _exec_wild_id(wild_id, _priv_exec->type)) != NULL) {
        _priv_exec->id = wild_id;
        res = _exec_files_XY_all(be, argp, getby_flag);
        if (res == NSS_SUCCESS)
            break;
    }
    _priv_exec->id = orig_id;
    if (old_id)
        free(old_id);

    return (res);
}


static nss_status_t
getbynam(files_backend_ptr_t be, void *a)
{
    nss_status_t    res;
    nss_XbyY_args_t *argp = (nss_XbyY_args_t *)a;

    res =  _exec_files_XY_all(be, argp, NSS_DBOP_EXECATTR_BYNAME);

    _exec_cleanup(res, argp);

    return (res);
}


static nss_status_t
getbyid(files_backend_ptr_t be, void *a)
{
    nss_status_t    res;
    nss_XbyY_args_t *argp = (nss_XbyY_args_t *)a;
    /*LINTED*/
    _priv_execattr  *_priv_exec = (_priv_execattr *)(argp->key.attrp);

    res = _exec_files_XY_all(be, argp, NSS_DBOP_EXECATTR_BYID);

    if (res != NSS_SUCCESS)
        res = get_wild(be, argp, NSS_DBOP_EXECATTR_BYID);

    _exec_cleanup(res, argp);

    return (res);
}


static nss_status_t
getbynameid(files_backend_ptr_t be, void *a)
{
    nss_status_t    res;
    nss_XbyY_args_t *argp = (nss_XbyY_args_t *)a;
    /*LINTED*/
    _priv_execattr  *_priv_exec = (_priv_execattr *)(argp->key.attrp);

    res = _exec_files_XY_all(be, argp, NSS_DBOP_EXECATTR_BYNAMEID);

    if (res != NSS_SUCCESS)
        res = get_wild(be, argp, NSS_DBOP_EXECATTR_BYNAMEID);

    _exec_cleanup(res, argp);

    return (res);
}


static files_backend_op_t execattr_ops[] = {
    _nss_files_destr,
    _nss_files_endent,
    _nss_files_setent,
    _nss_files_getent_netdb,
    getbynam,
    getbyid,
    getbynameid
};

/*ARGSUSED*/
nss_backend_t  *
_nss_files_exec_attr_constr(const char *dummy1,
    const char *dummy2,
    const char *dummy3,
    const char *dummy4,
    const char *dummy5,
    const char *dummy6,
    const char *dummy7)
{
    return (_nss_files_constr(execattr_ops,
        sizeof (execattr_ops)/sizeof (execattr_ops[0]),
        EXECATTR_FILENAME, NSS_LINELEN_EXECATTR, NULL));
}