getnetconfig.c

/*	$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 *__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 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_key_t nc_key;
static once_t nc_once = ONCE_INITIALIZER;
static int nc_key_error;

static void
nc_key_init(void)
{

	nc_key_error = thr_keycreate(&nc_key, free);
}

#define MAXNETCONFIGLINE    1000

static int *
__nc_error(void)
{
	static int nc_error = 0;
	int *nc_addr;

	/*
	 * Use the static `nc_error' if we are the main thread
	 * (including non-threaded programs), or if an allocation
	 * fails.
	 */
	if (thr_main())
		return (&nc_error);
	if (thr_once(&nc_once, nc_key_init) != 0 || nc_key_error != 0)
		return (&nc_error);
	if ((nc_addr = (int *)thr_getspecific(nc_key)) == NULL) {
		nc_addr = (int *)malloc(sizeof (int));
		if (thr_setspecific(nc_key, (void *) nc_addr) != 0) {
			free(nc_addr);
			return (&nc_error);
		}
		*nc_addr = 0;
	}
	return (nc_addr);
}

#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 = (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);
}