/*      $NetBSD: getnetconfig.c,v 1.3 2000/07/06 03:10:34 christos Exp $        */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */

/*
 * Copyright (c) 1989 by Sun Microsystems, Inc.
 */

#include "namespace.h"
#include "reentrant.h"
#include <stdio.h>
#include <errno.h>
#include <netconfig.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <rpc/rpc.h>
#include <unistd.h>
#include "un-namespace.h"
#include "rpc_com.h"

/*
 * The five library routines in this file provide application access to the
 * system network configuration database, /etc/netconfig.  In addition to the
 * netconfig database and the routines for accessing it, the environment
 * variable NETPATH and its corresponding routines in getnetpath.c may also be
 * used to specify the network transport to be used.
 */


/*
 * netconfig errors
 */

#define NC_NONETCONFIG  ENOENT
#define NC_NOMEM        ENOMEM
#define NC_NOTINIT      EINVAL      /* setnetconfig was not called first */
#define NC_BADFILE      EBADF       /* format for netconfig file is bad */
#define NC_NOTFOUND     ENOPROTOOPT /* specified netid was not found */

/*
 * semantics as strings (should be in netconfig.h)
 */
#define NC_TPI_CLTS_S       "tpi_clts"
#define NC_TPI_COTS_S       "tpi_cots"
#define NC_TPI_COTS_ORD_S   "tpi_cots_ord"
#define NC_TPI_RAW_S        "tpi_raw"

/*
 * flags as characters (also should be in netconfig.h)
 */
#define NC_NOFLAG_C     '-'
#define NC_VISIBLE_C    'v'
#define NC_BROADCAST_C  'b'

/*
 * Character used to indicate there is no name-to-address lookup library
 */
#define NC_NOLOOKUP     "-"

static const char * const _nc_errors[] = {
    "Netconfig database not found",
    "Not enough memory",
    "Not initialized",
    "Netconfig database has invalid format",
    "Netid not found in netconfig database"
};

struct netconfig_info {
    int         eof;    /* all entries has been read */
    int         ref;    /* # of times setnetconfig() has been called */
    struct netconfig_list       *head;  /* head of the list */
    struct netconfig_list       *tail;  /* last of the list */
};

struct netconfig_list {
    char                        *linep; /* hold line read from netconfig */
    struct netconfig            *ncp;
    struct netconfig_list       *next;
};

struct netconfig_vars {
    int   valid;        /* token that indicates a valid netconfig_vars */
    int   flag;         /* first time flag */
    struct netconfig_list *nc_configs;  /* pointer to the current netconfig entry */
};

#define NC_VALID        0xfeed
#define NC_STORAGE      0xf00d
#define NC_INVALID      0


static int parse_ncp(char *, struct netconfig *);
static struct netconfig *dup_ncp(struct netconfig *);


static FILE *nc_file;           /* for netconfig db */
static mutex_t nc_file_lock = MUTEX_INITIALIZER;

static struct netconfig_info    ni = { 0, 0, NULL, NULL};
static mutex_t ni_lock = MUTEX_INITIALIZER;

static _Thread_local int nc_error = 0;

#define MAXNETCONFIGLINE    1000

/*
 * A call to setnetconfig() establishes a /etc/netconfig "session".  A session
 * "handle" is returned on a successful call.  At the start of a session (after
 * a call to setnetconfig()) searches through the /etc/netconfig database will
 * proceed from the start of the file.  The session handle must be passed to
 * getnetconfig() to parse the file.  Each call to getnetconfig() using the
 * current handle will process one subsequent entry in /etc/netconfig.
 * setnetconfig() must be called before the first call to getnetconfig().
 * (Handles are used to allow for nested calls to setnetpath()).
 *
 * A new session is established with each call to setnetconfig(), with a new
 * handle being returned on each call.  Previously established sessions remain
 * active until endnetconfig() is called with that session's handle as an
 * argument.
 *
 * setnetconfig() need *not* be called before a call to getnetconfigent().
 * setnetconfig() returns a NULL pointer on failure (for example, if
 * the netconfig database is not present).
 */
void *
setnetconfig(void)
{
    struct netconfig_vars *nc_vars;

    if ((nc_vars = (struct netconfig_vars *)malloc(sizeof
                (struct netconfig_vars))) == NULL) {
        return(NULL);
    }

    /*
     * For multiple calls, i.e. nc_file is not NULL, we just return the
     * handle without reopening the netconfig db.
     */
    mutex_lock(&ni_lock);
    ni.ref++;
    mutex_unlock(&ni_lock);

    mutex_lock(&nc_file_lock);
    if ((nc_file != NULL) || (nc_file = fopen(NETCONFIG, "r")) != NULL) {
        nc_vars->valid = NC_VALID;
        nc_vars->flag = 0;
        nc_vars->nc_configs = ni.head;
        mutex_unlock(&nc_file_lock);
        return ((void *)nc_vars);
    }
    mutex_unlock(&nc_file_lock);

    mutex_lock(&ni_lock);
    ni.ref--;
    mutex_unlock(&ni_lock);

    nc_error = NC_NONETCONFIG;
    free(nc_vars);
    return (NULL);
}


/*
 * When first called, getnetconfig() returns a pointer to the first entry in
 * the netconfig database, formatted as a struct netconfig.  On each subsequent
 * call, getnetconfig() returns a pointer to the next entry in the database.
 * getnetconfig() can thus be used to search the entire netconfig file.
 * getnetconfig() returns NULL at end of file.
 */

struct netconfig *
getnetconfig(void *handlep)
{
    struct netconfig_vars *ncp = (struct netconfig_vars *)handlep;
    char *stringp;              /* tmp string pointer */
    struct netconfig_list       *list;
    struct netconfig *np;
    struct netconfig *result;

    /*
     * Verify that handle is valid
     */
    mutex_lock(&nc_file_lock);
    if (ncp == NULL || nc_file == NULL) {
        nc_error = NC_NOTINIT;
        mutex_unlock(&nc_file_lock);
        return (NULL);
    }
    mutex_unlock(&nc_file_lock);

    switch (ncp->valid) {
    case NC_VALID:
        /*
         * If entry has already been read into the list,
         * we return the entry in the linked list.
         * If this is the first time call, check if there are any entries in
         * linked list.  If no entries, we need to read the netconfig db.
         * If we have been here and the next entry is there, we just return
         * it.
         */
        if (ncp->flag == 0) {   /* first time */
            ncp->flag = 1;
            mutex_lock(&ni_lock);
            ncp->nc_configs = ni.head;
            mutex_unlock(&ni_lock);
            if (ncp->nc_configs != NULL)        /* entry already exist */
                return(ncp->nc_configs->ncp);
        }
        else if (ncp->nc_configs != NULL && ncp->nc_configs->next != NULL) {
            ncp->nc_configs = ncp->nc_configs->next;
            return(ncp->nc_configs->ncp);
        }

        /*
         * If we cannot find the entry in the list and is end of file,
         * we give up.
         */
        mutex_lock(&ni_lock);
        if (ni.eof == 1) {
                mutex_unlock(&ni_lock);
                return(NULL);
        }
        mutex_unlock(&ni_lock);

        break;
    default:
        nc_error = NC_NOTINIT;
        return (NULL);
    }

    stringp = (char *) malloc(MAXNETCONFIGLINE);
    if (stringp == NULL)
        return (NULL);

#ifdef MEM_CHK
    if (malloc_verify() == 0) {
        fprintf(stderr, "memory heap corrupted in getnetconfig\n");
        exit(1);
    }
#endif

    /*
     * Read a line from netconfig file.
     */
    mutex_lock(&nc_file_lock);
    do {
        if (fgets(stringp, MAXNETCONFIGLINE, nc_file) == NULL) {
            free(stringp);
            mutex_lock(&ni_lock);
            ni.eof = 1;
            mutex_unlock(&ni_lock);
            mutex_unlock(&nc_file_lock);
            return (NULL);
        }
    } while (*stringp == '#');
    mutex_unlock(&nc_file_lock);

    list = (struct netconfig_list *) malloc(sizeof (struct netconfig_list));
    if (list == NULL) {
        free(stringp);
        return(NULL);
    }
    np = (struct netconfig *) malloc(sizeof (struct netconfig));
    if (np == NULL) {
        free(stringp);
        free(list);
        return(NULL);
    }
    list->ncp = np;
    list->next = NULL;
    list->ncp->nc_lookups = NULL;
    list->linep = stringp;
    if (parse_ncp(stringp, list->ncp) == -1) {
        free(stringp);
        free(np);
        free(list);
        return (NULL);
    }
    else {
        /*
         * If this is the first entry that's been read, it is the head of
         * the list.  If not, put the entry at the end of the list.
         * Reposition the current pointer of the handle to the last entry
         * in the list.
         */
        mutex_lock(&ni_lock);
        if (ni.head == NULL) {  /* first entry */
            ni.head = ni.tail = list;
        }
        else {
            ni.tail->next = list;
            ni.tail = ni.tail->next;
        }
        ncp->nc_configs = ni.tail;
        result = ni.tail->ncp;
        mutex_unlock(&ni_lock);
        return(result);
    }
}

/*
 * endnetconfig() may be called to "unbind" or "close" the netconfig database
 * when processing is complete, releasing resources for reuse.  endnetconfig()
 * may not be called before setnetconfig().  endnetconfig() returns 0 on
 * success and -1 on failure (for example, if setnetconfig() was not called
 * previously).
 */
int
endnetconfig(void *handlep)
{
    struct netconfig_vars *nc_handlep = (struct netconfig_vars *)handlep;

    struct netconfig_list *q, *p;

    /*
     * Verify that handle is valid
     */
    if (nc_handlep == NULL || (nc_handlep->valid != NC_VALID &&
            nc_handlep->valid != NC_STORAGE)) {
        nc_error = NC_NOTINIT;
        return (-1);
    }

    /*
     * Return 0 if anyone still needs it.
     */
    nc_handlep->valid = NC_INVALID;
    nc_handlep->flag = 0;
    nc_handlep->nc_configs = NULL;
    mutex_lock(&ni_lock);
    if (--ni.ref > 0) {
        mutex_unlock(&ni_lock);
        free(nc_handlep);
        return(0);
    }

    /*
     * No one needs these entries anymore, then frees them.
     * Make sure all info in netconfig_info structure has been reinitialized.
     */
    q = ni.head;
    ni.eof = ni.ref = 0;
    ni.head = NULL;
    ni.tail = NULL;
    mutex_unlock(&ni_lock);

    while (q != NULL) {
        p = q->next;
        free(q->ncp->nc_lookups);
        free(q->ncp);
        free(q->linep);
        free(q);
        q = p;
    }
    free(nc_handlep);

    mutex_lock(&nc_file_lock);
    fclose(nc_file);
    nc_file = NULL;
    mutex_unlock(&nc_file_lock);

    return (0);
}

/*
 * getnetconfigent(netid) returns a pointer to the struct netconfig structure
 * corresponding to netid.  It returns NULL if netid is invalid (that is, does
 * not name an entry in the netconfig database).  It returns NULL and sets
 * errno in case of failure (for example, if the netconfig database cannot be
 * opened).
 */

struct netconfig *
getnetconfigent(const char *netid)
{
    FILE *file;         /* NETCONFIG db's file pointer */
    char *linep;        /* holds current netconfig line */
    char *stringp;      /* temporary string pointer */
    struct netconfig *ncp = NULL;   /* returned value */
    struct netconfig_list *list;        /* pointer to cache list */

    nc_error = NC_NOTFOUND;     /* default error. */
    if (netid == NULL || strlen(netid) == 0) {
        return (NULL);
    }

    /*
     * Look up table if the entries have already been read and parsed in
     * getnetconfig(), then copy this entry into a buffer and return it.
     * If we cannot find the entry in the current list and there are more
     * entries in the netconfig db that has not been read, we then read the
     * db and try find the match netid.
     * If all the netconfig db has been read and placed into the list and
     * there is no match for the netid, return NULL.
     */
    mutex_lock(&ni_lock);
    if (ni.head != NULL) {
        for (list = ni.head; list; list = list->next) {
            if (strcmp(list->ncp->nc_netid, netid) == 0) {
                mutex_unlock(&ni_lock);
                return(dup_ncp(list->ncp));
            }
        }
        if (ni.eof == 1) {      /* that's all the entries */
                mutex_unlock(&ni_lock);
                return(NULL);
        }
    }
    mutex_unlock(&ni_lock);


    if ((file = fopen(NETCONFIG, "r")) == NULL) {
        nc_error = NC_NONETCONFIG;
        return (NULL);
    }

    if ((linep = malloc(MAXNETCONFIGLINE)) == NULL) {
        fclose(file);
        nc_error = NC_NOMEM;
        return (NULL);
    }
    do {
        ptrdiff_t len;
        char *tmpp;     /* tmp string pointer */

        do {
            if ((stringp = fgets(linep, MAXNETCONFIGLINE, file)) == NULL) {
                break;
            }
        } while (*stringp == '#');
        if (stringp == NULL) {      /* eof */
            break;
        }
        if ((tmpp = strpbrk(stringp, "\t ")) == NULL) { /* can't parse file */
            nc_error = NC_BADFILE;
            break;
        }
        if (strlen(netid) == (size_t) (len = tmpp - stringp) && /* a match */
                strncmp(stringp, netid, (size_t)len) == 0) {
            if ((ncp = (struct netconfig *)
                    malloc(sizeof (struct netconfig))) == NULL) {
                break;
            }
            ncp->nc_lookups = NULL;
            if (parse_ncp(linep, ncp) == -1) {
                free(ncp);
                ncp = NULL;
            }
            break;
        }
    } while (stringp != NULL);
    if (ncp == NULL) {
        free(linep);
    }
    fclose(file);
    return(ncp);
}

/*
 * freenetconfigent(netconfigp) frees the netconfig structure pointed to by
 * netconfigp (previously returned by getnetconfigent()).
 */

void
freenetconfigent(struct netconfig *netconfigp)
{
    if (netconfigp != NULL) {
        free(netconfigp->nc_netid);     /* holds all netconfigp's strings */
        free(netconfigp->nc_lookups);
        free(netconfigp);
    }
    return;
}

/*
 * Parse line and stuff it in a struct netconfig
 * Typical line might look like:
 *      udp tpi_cots vb inet udp /dev/udp /usr/lib/ip.so,/usr/local/ip.so
 *
 * We return -1 if any of the tokens don't parse, or malloc fails.
 *
 * Note that we modify stringp (putting NULLs after tokens) and
 * we set the ncp's string field pointers to point to these tokens within
 * stringp.
 *
 * stringp - string to parse
 * ncp     - where to put results
 */

static int
parse_ncp(char *stringp, struct netconfig *ncp)
{
    char    *tokenp;    /* for processing tokens */
    char    *lasts;
    char    **nc_lookups;

    nc_error = NC_BADFILE;      /* nearly anything that breaks is for this reason */
    stringp[strlen(stringp)-1] = '\0';  /* get rid of newline */
    /* netid */
    if ((ncp->nc_netid = strtok_r(stringp, "\t ", &lasts)) == NULL) {
        return (-1);
    }

    /* semantics */
    if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    if (strcmp(tokenp, NC_TPI_COTS_ORD_S) == 0)
        ncp->nc_semantics = NC_TPI_COTS_ORD;
    else if (strcmp(tokenp, NC_TPI_COTS_S) == 0)
        ncp->nc_semantics = NC_TPI_COTS;
    else if (strcmp(tokenp, NC_TPI_CLTS_S) == 0)
        ncp->nc_semantics = NC_TPI_CLTS;
    else if (strcmp(tokenp, NC_TPI_RAW_S) == 0)
        ncp->nc_semantics = NC_TPI_RAW;
    else
        return (-1);

    /* flags */
    if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    for (ncp->nc_flag = NC_NOFLAG; *tokenp != '\0';
            tokenp++) {
        switch (*tokenp) {
        case NC_NOFLAG_C:
            break;
        case NC_VISIBLE_C:
            ncp->nc_flag |= NC_VISIBLE;
            break;
        case NC_BROADCAST_C:
            ncp->nc_flag |= NC_BROADCAST;
            break;
        default:
            return (-1);
        }
    }
    /* protocol family */
    if ((ncp->nc_protofmly = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    /* protocol name */
    if ((ncp->nc_proto = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    /* network device */
    if ((ncp->nc_device = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
        return (-1);
    }
    if (strcmp(tokenp, NC_NOLOOKUP) == 0) {
        ncp->nc_nlookups = 0;
        ncp->nc_lookups = NULL;
    } else {
        char *cp;           /* tmp string */

        free(ncp->nc_lookups); /* from last visit */
        ncp->nc_lookups = NULL;
        ncp->nc_nlookups = 0;
        while ((cp = tokenp) != NULL) {
            if ((nc_lookups = reallocarray(ncp->nc_lookups,
                ncp->nc_nlookups + 1, sizeof(*ncp->nc_lookups))) == NULL) {
                    free(ncp->nc_lookups);
                    ncp->nc_lookups = NULL;
                    return (-1);
            }
            tokenp = _get_next_token(cp, ',');
            ncp->nc_lookups = nc_lookups;
            ncp->nc_lookups[ncp->nc_nlookups++] = cp;
        }
    }
    return (0);
}


/*
 * Returns a string describing the reason for failure.
 */
char *
nc_sperror(void)
{
    const char *message;

    switch(nc_error) {
    case NC_NONETCONFIG:
        message = _nc_errors[0];
        break;
    case NC_NOMEM:
        message = _nc_errors[1];
        break;
    case NC_NOTINIT:
        message = _nc_errors[2];
        break;
    case NC_BADFILE:
        message = _nc_errors[3];
        break;
    case NC_NOTFOUND:
        message = _nc_errors[4];
        break;
    default:
        message = "Unknown network selection error";
    }
    /* LINTED const castaway */
    return ((char *)message);
}

/*
 * Prints a message onto standard error describing the reason for failure.
 */
void
nc_perror(const char *s)
{
    fprintf(stderr, "%s: %s\n", s, nc_sperror());
}

/*
 * Duplicates the matched netconfig buffer.
 */
static struct netconfig *
dup_ncp(struct netconfig *ncp)
{
    struct netconfig    *p;
    char        *tmp;
    u_int       i;

    if ((tmp=malloc(MAXNETCONFIGLINE)) == NULL)
        return(NULL);
    if ((p=(struct netconfig *)malloc(sizeof(struct netconfig))) == NULL) {
        free(tmp);
        return(NULL);
    }
    /*
     * First we dup all the data from matched netconfig buffer.  Then we
     * adjust some of the member pointer to a pre-allocated buffer where
     * contains part of the data.
     * To follow the convention used in parse_ncp(), we store all the
     * necessary information in the pre-allocated buffer and let each
     * of the netconfig char pointer member point to the right address
     * in the buffer.
     */
    *p = *ncp;
    p->nc_netid = (char *)strcpy(tmp,ncp->nc_netid);
    tmp = strchr(tmp, '\0') + 1;
    p->nc_protofmly = (char *)strcpy(tmp,ncp->nc_protofmly);
    tmp = strchr(tmp, '\0') + 1;
    p->nc_proto = (char *)strcpy(tmp,ncp->nc_proto);
    tmp = strchr(tmp, '\0') + 1;
    p->nc_device = (char *)strcpy(tmp,ncp->nc_device);
    p->nc_lookups = (char **)malloc((size_t)(p->nc_nlookups+1) * sizeof(char *));
    if (p->nc_lookups == NULL) {
        free(p->nc_netid);
        free(p);
        return(NULL);
    }
    for (i=0; i < p->nc_nlookups; i++) {
        tmp = strchr(tmp, '\0') + 1;
        p->nc_lookups[i] = (char *)strcpy(tmp,ncp->nc_lookups[i]);
    }
    return(p);
}