/*
 * 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.
 * Copyright (c) 2017, Joyent, Inc.
 */

#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 *);

/*
 * _exec_files_XY_all wants to cache data from the attribute file.
 */
static char *exec_f_buf;
static time_t exec_read_time;

void
getexecattr_fini(void)
{
        free(exec_f_buf);
        exec_f_buf = NULL;
}


/*
 * 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;
        char            *first;
        char            *last;
        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 > exec_read_time || exec_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 (exec_f_buf != NULL)
                        free(exec_f_buf);
                if ((exec_f_buf = malloc(f_size)) == NULL) {
                        (void) _nss_files_endent(be, 0);
                        (void) rw_unlock(&exec_lock);
                        return (NSS_UNAVAIL);
                }
                if (read(exec_fd, exec_f_buf, f_size) < f_size) {
                        free(exec_f_buf);
                        exec_f_buf = NULL;
                        (void) _nss_files_endent(be, 0);
                        (void) rw_unlock(&exec_lock);
                        return (NSS_UNAVAIL);
                }
                exec_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(exec_f_buf);
                        exec_f_buf = NULL;
                        (void) _nss_files_endent(be, 0);
                        return (NSS_UNAVAIL);
                }
                if (stat(be->filename, &f_stat) != 0) {
                        free(exec_f_buf);
                        exec_f_buf = NULL;
                        (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(exec_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));
}