lib/libc/rpc/getnetpath.c

   1 /*-
   2  * Copyright (c) 2009, Sun Microsystems, Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are met:
   7  * - Redistributions of source code must retain the above copyright notice,
   8  *   this list of conditions and the following disclaimer.
   9  * - Redistributions in binary form must reproduce the above copyright notice,
  10  *   this list of conditions and the following disclaimer in the documentation
  11  *   and/or other materials provided with the distribution.
  12  * - Neither the name of Sun Microsystems, Inc. nor the names of its
  13  *   contributors may be used to endorse or promote products derived
  14  *   from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * @(#)getnetpath.c     1.11 91/12/19 SMI
  29  * $NetBSD: getnetpath.c,v 1.3 2000/07/06 03:10:34 christos Exp $
  30  * $FreeBSD: src/lib/libc/rpc/getnetpath.c,v 1.8 2007/09/20 22:35:24 matteo Exp $
  31  */
  32
  33 /*
  34  * Copyright (c) 1989 by Sun Microsystems, Inc.
  35  */
  36
  37 #include "namespace.h"
  38 #include <stdio.h>
  39 #include <errno.h>
  40 #include <netconfig.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <syslog.h>
  44 #include "un-namespace.h"
  45
  46 /*
  47  * internal structure to keep track of a netpath "session"
  48  */
  49 struct netpath_chain {
  50     struct netconfig *ncp;  /* an nconf entry */
  51     struct netpath_chain *nchain_next;  /* next nconf entry allocated */
  52 };
  53
  54
  55 struct netpath_vars {
  56     int   valid;            /* token that indicates a valid netpath_vars */
  57     void *nc_handlep;       /* handle for current netconfig "session" */
  58     char *netpath;          /* pointer to current view-point in NETPATH */
  59     char *netpath_start;    /* pointer to start of our copy of NETPATH */
  60     struct netpath_chain *ncp_list;  /* list of nconfs allocated this session*/
  61 };
  62
  63 #define NP_VALID        0xf00d
  64 #define NP_INVALID      0
  65
  66 char *_get_next_token(char *, int);
  67
  68
  69 /*
  70  * A call to setnetpath() establishes a NETPATH "session".  setnetpath()
  71  * must be called before the first call to getnetpath().  A "handle" is
  72  * returned to distinguish the session; this handle should be passed
  73  * subsequently to getnetpath().  (Handles are used to allow for nested calls
  74  * to setnetpath()).
  75  * If setnetpath() is unable to establish a session (due to lack of memory
  76  * resources, or the absence of the /etc/netconfig file), a NULL pointer is
  77  * returned.
  78  */
  79
  80 void *
  81 setnetpath(void)
  82 {
  83
  84     struct netpath_vars *np_sessionp;   /* this session's variables */
  85     char *npp;                          /* NETPATH env variable */
  86
  87 #ifdef MEM_CHK
  88     malloc_debug(1);
  89 #endif
  90
  91     if ((np_sessionp =
  92         (struct netpath_vars *)malloc(sizeof (struct netpath_vars))) == NULL) {
  93         return (NULL);
  94     }
  95     if ((np_sessionp->nc_handlep = setnetconfig()) == NULL) {
  96         syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
  97         goto failed;
  98     }
  99     np_sessionp->valid = NP_VALID;
 100     np_sessionp->ncp_list = NULL;
 101     if ((npp = getenv(NETPATH)) == NULL) {
 102         np_sessionp->netpath = NULL;
 103     } else {
 104         endnetconfig(np_sessionp->nc_handlep);/* won't need nc session*/
 105         np_sessionp->nc_handlep = NULL;
 106         if ((np_sessionp->netpath = malloc(strlen(npp)+1)) == NULL)
 107                 goto failed;
 108         else {
 109             strcpy(np_sessionp->netpath, npp);
 110         }
 111     }
 112     np_sessionp->netpath_start = np_sessionp->netpath;
 113     return ((void *)np_sessionp);
 114
 115 failed:
 116     free(np_sessionp);
 117     return (NULL);
 118 }
 119
 120 /*
 121  * When first called, getnetpath() returns a pointer to the netconfig
 122  * database entry corresponding to the first valid NETPATH component.  The
 123  * netconfig entry is formatted as a struct netconfig.
 124  * On each subsequent call, getnetpath returns a pointer to the netconfig
 125  * entry that corresponds to the next valid NETPATH component.  getnetpath
 126  * can thus be used to search the netconfig database for all networks
 127  * included in the NETPATH variable.
 128  * When NETPATH has been exhausted, getnetpath() returns NULL.  It returns
 129  * NULL and sets errno in case of an error (e.g., setnetpath was not called
 130  * previously).
 131  * getnetpath() silently ignores invalid NETPATH components.  A NETPATH
 132  * compnent is invalid if there is no corresponding entry in the netconfig
 133  * database.
 134  * If the NETPATH variable is unset, getnetpath() behaves as if NETPATH
 135  * were set to the sequence of default or visible networks in the netconfig
 136  * database, in the order in which they are listed.
 137  */
 138
 139 struct netconfig *
 140 getnetpath(void *handlep)
 141 {
 142     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
 143     struct netconfig *ncp = NULL;   /* temp. holds a netconfig session */
 144     struct netpath_chain *chainp;   /* holds chain of ncp's we alloc */
 145     char  *npp;         /* holds current NETPATH */
 146
 147     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
 148         errno = EINVAL;
 149         return (NULL);
 150     }
 151     if (np_sessionp->netpath_start == NULL) {   /* NETPATH was not set */
 152         do {                /* select next visible network */
 153             if (np_sessionp->nc_handlep == NULL) {
 154                 np_sessionp->nc_handlep = setnetconfig();
 155                 if (np_sessionp->nc_handlep == NULL)
 156                     syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
 157             }
 158             if ((ncp = getnetconfig(np_sessionp->nc_handlep)) == NULL) {
 159                 return(NULL);
 160             }
 161         } while ((ncp->nc_flag & NC_VISIBLE) == 0);
 162         return (ncp);
 163     }
 164     /*
 165      * Find first valid network ID in netpath.
 166      */
 167     while ((npp = np_sessionp->netpath) != NULL && strlen(npp) != 0) {
 168         np_sessionp->netpath = _get_next_token(npp, ':');
 169         /*
 170          * npp is a network identifier.
 171          */
 172         if ((ncp = getnetconfigent(npp)) != NULL) {
 173             chainp = (struct netpath_chain *)   /* cobble alloc chain entry */
 174                     malloc(sizeof (struct netpath_chain));
 175             chainp->ncp = ncp;
 176             chainp->nchain_next = NULL;
 177             if (np_sessionp->ncp_list == NULL) {
 178                 np_sessionp->ncp_list = chainp;
 179             } else {
 180                 np_sessionp->ncp_list->nchain_next = chainp;
 181             }
 182             return (ncp);
 183         }
 184         /* couldn't find this token in the database; go to next one. */
 185     }
 186     return (NULL);
 187 }
 188
 189 /*
 190  * endnetpath() may be called to unbind NETPATH when processing is complete,
 191  * releasing resources for reuse.  It returns 0 on success and -1 on failure
 192  * (e.g. if setnetpath() was not called previously.
 193  */
 194 int
 195 endnetpath(void *handlep)
 196 {
 197     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
 198     struct netpath_chain *chainp, *lastp;
 199
 200     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
 201         errno = EINVAL;
 202         return (-1);
 203     }
 204     if (np_sessionp->nc_handlep != NULL)
 205         endnetconfig(np_sessionp->nc_handlep);
 206     if (np_sessionp->netpath_start != NULL)
 207         free(np_sessionp->netpath_start);
 208     for (chainp = np_sessionp->ncp_list; chainp != NULL;
 209             lastp=chainp, chainp=chainp->nchain_next, free(lastp)) {
 210         freenetconfigent(chainp->ncp);
 211     }
 212     free(np_sessionp);
 213 #ifdef MEM_CHK
 214     if (malloc_verify() == 0) {
 215         fprintf(stderr, "memory heap corrupted in endnetpath\n");
 216         exit(1);
 217     }
 218 #endif
 219     return (0);
 220 }
 221
 222
 223
 224 /*
 225  * Returns pointer to the rest-of-the-string after the current token.
 226  * The token itself starts at arg, and we null terminate it.  We return NULL
 227  * if either the arg is empty, or if this is the last token.
 228  */
 229
 230 char *
 231 _get_next_token(char *npp,              /* string */
 232                 int token)              /* char to parse string for */
 233 {
 234     char  *cp;          /* char pointer */
 235     char  *np;          /* netpath pointer */
 236     char  *ep;          /* escape pointer */
 237
 238     if ((cp = strchr(npp, token)) == NULL) {
 239         return (NULL);
 240     }
 241     /*
 242      * did find a token, but it might be escaped.
 243      */
 244     if ((cp > npp) && (cp[-1] == '\\')) {
 245         /* if slash was also escaped, carry on, otherwise find next token */
 246         if ((cp > npp + 1) && (cp[-2] != '\\')) {
 247             /* shift r-o-s  onto the escaped token */
 248             strcpy(&cp[-1], cp);    /* XXX: overlapping string copy */
 249             /*
 250              * Do a recursive call.
 251              * We don't know how many escaped tokens there might be.
 252              */
 253             return (_get_next_token(cp, token));
 254         }
 255     }
 256
 257     *cp++ = '\0';               /* null-terminate token */
 258     /* get rid of any backslash escapes */
 259     ep = npp;
 260     while ((np = strchr(ep, '\\')) != NULL) {
 261         if (np[1] == '\\')
 262             np++;
 263         strcpy(np, (ep = &np[1]));  /* XXX: overlapping string copy */
 264     }
 265     return (cp);                /* return ptr to r-o-s */
 266 }