/*      $NetBSD: getnetconfig.c,v 1.25 2017/06/30 10:03:34 christos Exp $       */

/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * 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 the "Oracle America, 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static        char sccsid[] = "@(#)getnetconfig.c       1.12 91/12/19 SMI";
#else
__RCSID("$NetBSD: getnetconfig.c,v 1.25 2017/06/30 10:03:34 christos Exp $");
#endif
#endif

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

#include "namespace.h"
#include "reentrant.h"
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <netconfig.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <rpc/rpc.h>
#include "rpc_internal.h"

#ifdef __weak_alias
__weak_alias(getnetconfig,_getnetconfig)
__weak_alias(setnetconfig,_setnetconfig)
__weak_alias(endnetconfig,_endnetconfig)
__weak_alias(getnetconfigent,_getnetconfigent)
__weak_alias(freenetconfigent,_freenetconfigent)
__weak_alias(nc_perror,_nc_perror)
__weak_alias(nc_sperror,_nc_sperror)
#endif

/*
 * 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 */

/*
 * 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"
};

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


static FILE *nc_file;           /* for netconfig db */
static struct netconfig_info    ni = { 0, 0, NULL, NULL};

#define MAXNETCONFIGLINE    1000

#ifdef _REENTRANT
static thread_key_t nc_key;
static once_t nc_once = ONCE_INITIALIZER;

static void 
__nc_error_setup(void)
{
        thr_keycreate(&nc_key, free);
}
#endif

static int *
__nc_error(void)
{
#ifdef _REENTRANT
        int *nc_addr = NULL;
#endif
        static int nc_error = 0;

#ifdef _REENTRANT
        if (__isthreaded == 0)
                return &nc_error;
        thr_once(&nc_once, __nc_error_setup);
        nc_addr = thr_getspecific(nc_key) ;
        if (nc_addr == NULL) {
                nc_addr = malloc(sizeof (int));
                if (nc_addr == NULL)
                        return &nc_error;
                if (thr_setspecific(nc_key, nc_addr) != 0) {
                        if (nc_addr)
                                free(nc_addr);
                        return &nc_error;
                }
                *nc_addr = 0;
        }
        return nc_addr;
#else
        return &nc_error;
#endif
}

#define nc_error        (*(__nc_error()))
/*
 * 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 = malloc(sizeof(*nc_vars))) == NULL) {
                return NULL;
        }

        /*
         * For multiple calls, i.e. nc_file is not NULL, we just return the
         * handle without reopening the netconfig db.
         */
        ni.ref++;
        if ((nc_file != NULL) || (nc_file = fopen(NETCONFIG, "re")) != NULL) {
                nc_vars->valid = NC_VALID;
                nc_vars->flag = 0;
                nc_vars->nc_configs = ni.head;
                return nc_vars;
        }
        ni.ref--;
        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 = handlep;
        char *stringp;          /* tmp string pointer */
        struct netconfig_list   *list;
        struct netconfig *np;

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

        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;
                        ncp->nc_configs = ni.head;
                        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.
                 */
                if (ni.eof == 1)
                        return NULL;
                break;
        default:
                nc_error = NC_NOTINIT;
                return NULL;
        }

        stringp = 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.
         */
        do {
                if (fgets(stringp, MAXNETCONFIGLINE, nc_file) == NULL) {
                        free(stringp);
                        ni.eof = 1;
                        return NULL;
                }
        } while (*stringp == '#');

        list = malloc(sizeof(*list));
        if (list == NULL) {
                free(stringp);
                return NULL;
        }
        np = malloc(sizeof(*np));
        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.
                 */
                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;
                return ni.tail->ncp;
        }
}

/*
 * 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 = 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;
        if (--ni.ref > 0) {
                free(nc_handlep);
                return 0;
        }

        /*
         * Noone needs these entries anymore, then frees them.
         * Make sure all info in netconfig_info structure has been
         * reinitialized.
         */
        q = p = ni.head;
        ni.eof = ni.ref = 0;
        ni.head = NULL;
        ni.tail = NULL;
        while (q) {
                p = q->next;
                if (q->ncp->nc_lookups != NULL) free(q->ncp->nc_lookups);
                free(q->ncp);
                free(q->linep);
                free(q);
                q = p;
        }
        free(nc_handlep);

        fclose(nc_file);
        nc_file = NULL;
        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 */

        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.
         */
        if (ni.head != NULL) {
                for (list = ni.head; list; list = list->next) {
                        if (strcmp(list->ncp->nc_netid, netid) == 0)
                                return dup_ncp(list->ncp);
                }
                if (ni.eof == 1)        /* that's all the entries */
                        return NULL;
        }

        if ((file = fopen(NETCONFIG, "re")) == NULL)
            return NULL;

        if ((linep = malloc(MAXNETCONFIGLINE)) == NULL) {
                fclose(file);
                return NULL;
        }
        do {
                size_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) == (len = (size_t)(tmpp - stringp)) &&
                    strncmp(stringp, netid, len) == 0) {
                    /* a match */
                        if ((ncp = malloc(sizeof(*ncp))) == 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) {
                                /* holds all netconfigp's strings */
                free(netconfigp->nc_netid);
                if (netconfigp->nc_lookups != NULL)
                        free(netconfigp->nc_lookups);
                free(netconfigp);
        }
}

/*
 * 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.
 */

static int
parse_ncp(
        char *stringp,          /* string to parse */
        struct netconfig *ncp)  /* where to put results */
{
        char    *tokenp;        /* for processing tokens */
        char    *lasts;

        _DIAGASSERT(stringp != NULL);
        _DIAGASSERT(ncp != NULL);

        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 */

                if (ncp->nc_lookups != NULL)    /* from last visit */
                        free(ncp->nc_lookups);
                /* preallocate one string pointer */
                ncp->nc_lookups = malloc(sizeof(*ncp->nc_lookups));
                ncp->nc_nlookups = 0;
                while ((cp = tokenp) != NULL) {
                        tokenp = _get_next_token(cp, ',');
                        ncp->nc_lookups[(size_t)ncp->nc_nlookups++] = cp;
                        ncp->nc_lookups = (char **)
                            realloc(ncp->nc_lookups,
                            (size_t)(ncp->nc_nlookups+1) *sizeof(char *));      
                                                /* for next loop */
                }
        }
        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;
        default:
                message = "Unknown network selection error";
        }
        return __UNCONST(message);
}

/*
 * Prints a message onto standard error describing the reason for failure.
 */
void
nc_perror(const char *s)
{

        _DIAGASSERT(s != NULL);

        fprintf(stderr, "%s: %s", s, nc_sperror());
}

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

        _DIAGASSERT(ncp != NULL);

        if ((tmp = malloc(MAXNETCONFIGLINE)) == NULL)
                return NULL;
        if ((p = malloc(sizeof(*p))) == 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 = strcpy(tmp, ncp->nc_netid);
        tmp = strchr(tmp, '\0') + 1;
        p->nc_protofmly = strcpy(tmp, ncp->nc_protofmly);
        tmp = strchr(tmp, '\0') + 1;
        p->nc_proto = strcpy(tmp, ncp->nc_proto);
        tmp = strchr(tmp, '\0') + 1;
        p->nc_device = strcpy(tmp, ncp->nc_device);
        p->nc_lookups = calloc((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] = strcpy(tmp, ncp->nc_lookups[i]);
        }
        return p;
}