lib/libc/rpc/getnetpath.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user or with the express written consent of
   8  * Sun Microsystems, Inc.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  *
  30  * @(#)getnetpath.c     1.11 91/12/19 SMI
  31  * $NetBSD: getnetpath.c,v 1.3 2000/07/06 03:10:34 christos Exp $
  32  * $FreeBSD: src/lib/libc/rpc/getnetpath.c,v 1.8 2007/09/20 22:35:24 matteo Exp $
  33  */
  34
  35 /*
  36  * Copyright (c) 1989 by Sun Microsystems, Inc.
  37  */
  38
  39 #include "namespace.h"
  40 #include <stdio.h>
  41 #include <errno.h>
  42 #include <netconfig.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <syslog.h>
  46 #include "un-namespace.h"
  47
  48 /*
  49  * internal structure to keep track of a netpath "session"
  50  */
  51 struct netpath_chain {
  52     struct netconfig *ncp;  /* an nconf entry */
  53     struct netpath_chain *nchain_next;  /* next nconf entry allocated */
  54 };
  55
  56
  57 struct netpath_vars {
  58     int   valid;            /* token that indicates a valid netpath_vars */
  59     void *nc_handlep;       /* handle for current netconfig "session" */
  60     char *netpath;          /* pointer to current view-point in NETPATH */
  61     char *netpath_start;    /* pointer to start of our copy of NETPATH */
  62     struct netpath_chain *ncp_list;  /* list of nconfs allocated this session*/
  63 };
  64
  65 #define NP_VALID        0xf00d
  66 #define NP_INVALID      0
  67
  68 char *_get_next_token(char *, int);
  69
  70
  71 /*
  72  * A call to setnetpath() establishes a NETPATH "session".  setnetpath()
  73  * must be called before the first call to getnetpath().  A "handle" is
  74  * returned to distinguish the session; this handle should be passed
  75  * subsequently to getnetpath().  (Handles are used to allow for nested calls
  76  * to setnetpath()).
  77  * If setnetpath() is unable to establish a session (due to lack of memory
  78  * resources, or the absence of the /etc/netconfig file), a NULL pointer is
  79  * returned.
  80  */
  81
  82 void *
  83 setnetpath(void)
  84 {
  85
  86     struct netpath_vars *np_sessionp;   /* this session's variables */
  87     char *npp;                          /* NETPATH env variable */
  88
  89 #ifdef MEM_CHK
  90     malloc_debug(1);
  91 #endif
  92
  93     if ((np_sessionp =
  94         (struct netpath_vars *)malloc(sizeof (struct netpath_vars))) == NULL) {
  95         return (NULL);
  96     }
  97     if ((np_sessionp->nc_handlep = setnetconfig()) == NULL) {
  98         free(np_sessionp);
  99         syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
 100         goto failed;
 101     }
 102     np_sessionp->valid = NP_VALID;
 103     np_sessionp->ncp_list = NULL;
 104     if ((npp = getenv(NETPATH)) == NULL) {
 105         np_sessionp->netpath = NULL;
 106     } else {
 107         endnetconfig(np_sessionp->nc_handlep);/* won't need nc session*/
 108         np_sessionp->nc_handlep = NULL;
 109         if ((np_sessionp->netpath = malloc(strlen(npp)+1)) == NULL)
 110                 goto failed;
 111         else {
 112             strcpy(np_sessionp->netpath, npp);
 113         }
 114     }
 115     np_sessionp->netpath_start = np_sessionp->netpath;
 116     return ((void *)np_sessionp);
 117
 118 failed:
 119     free(np_sessionp);
 120     return (NULL);
 121 }
 122
 123 /*
 124  * When first called, getnetpath() returns a pointer to the netconfig
 125  * database entry corresponding to the first valid NETPATH component.  The
 126  * netconfig entry is formatted as a struct netconfig.
 127  * On each subsequent call, getnetpath returns a pointer to the netconfig
 128  * entry that corresponds to the next valid NETPATH component.  getnetpath
 129  * can thus be used to search the netconfig database for all networks
 130  * included in the NETPATH variable.
 131  * When NETPATH has been exhausted, getnetpath() returns NULL.  It returns
 132  * NULL and sets errno in case of an error (e.g., setnetpath was not called
 133  * previously).
 134  * getnetpath() silently ignores invalid NETPATH components.  A NETPATH
 135  * compnent is invalid if there is no corresponding entry in the netconfig
 136  * database.
 137  * If the NETPATH variable is unset, getnetpath() behaves as if NETPATH
 138  * were set to the sequence of default or visible networks in the netconfig
 139  * database, in the order in which they are listed.
 140  */
 141
 142 struct netconfig *
 143 getnetpath(void *handlep)
 144 {
 145     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
 146     struct netconfig *ncp = NULL;   /* temp. holds a netconfig session */
 147     struct netpath_chain *chainp;   /* holds chain of ncp's we alloc */
 148     char  *npp;         /* holds current NETPATH */
 149
 150     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
 151         errno = EINVAL;
 152         return (NULL);
 153     }
 154     if (np_sessionp->netpath_start == NULL) {   /* NETPATH was not set */
 155         do {                /* select next visible network */
 156             if (np_sessionp->nc_handlep == NULL) {
 157                 np_sessionp->nc_handlep = setnetconfig();
 158                 if (np_sessionp->nc_handlep == NULL)
 159                     syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
 160             }
 161             if ((ncp = getnetconfig(np_sessionp->nc_handlep)) == NULL) {
 162                 return(NULL);
 163             }
 164         } while ((ncp->nc_flag & NC_VISIBLE) == 0);
 165         return (ncp);
 166     }
 167     /*
 168      * Find first valid network ID in netpath.
 169      */
 170     while ((npp = np_sessionp->netpath) != NULL && strlen(npp) != 0) {
 171         np_sessionp->netpath = _get_next_token(npp, ':');
 172         /*
 173          * npp is a network identifier.
 174          */
 175         if ((ncp = getnetconfigent(npp)) != NULL) {
 176             chainp = (struct netpath_chain *)   /* cobble alloc chain entry */
 177                     malloc(sizeof (struct netpath_chain));
 178             chainp->ncp = ncp;
 179             chainp->nchain_next = NULL;
 180             if (np_sessionp->ncp_list == NULL) {
 181                 np_sessionp->ncp_list = chainp;
 182             } else {
 183                 np_sessionp->ncp_list->nchain_next = chainp;
 184             }
 185             return (ncp);
 186         }
 187         /* couldn't find this token in the database; go to next one. */
 188     }
 189     return (NULL);
 190 }
 191
 192 /*
 193  * endnetpath() may be called to unbind NETPATH when processing is complete,
 194  * releasing resources for reuse.  It returns 0 on success and -1 on failure
 195  * (e.g. if setnetpath() was not called previously.
 196  */
 197 int
 198 endnetpath(void *handlep)
 199 {
 200     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
 201     struct netpath_chain *chainp, *lastp;
 202
 203     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
 204         errno = EINVAL;
 205         return (-1);
 206     }
 207     if (np_sessionp->nc_handlep != NULL)
 208         endnetconfig(np_sessionp->nc_handlep);
 209     if (np_sessionp->netpath_start != NULL)
 210         free(np_sessionp->netpath_start);
 211     for (chainp = np_sessionp->ncp_list; chainp != NULL;
 212             lastp=chainp, chainp=chainp->nchain_next, free(lastp)) {
 213         freenetconfigent(chainp->ncp);
 214     }
 215     free(np_sessionp);
 216 #ifdef MEM_CHK
 217     if (malloc_verify() == 0) {
 218         fprintf(stderr, "memory heap corrupted in endnetpath\n");
 219         exit(1);
 220     }
 221 #endif
 222     return (0);
 223 }
 224
 225
 226
 227 /*
 228  * Returns pointer to the rest-of-the-string after the current token.
 229  * The token itself starts at arg, and we null terminate it.  We return NULL
 230  * if either the arg is empty, or if this is the last token.
 231  */
 232
 233 char *
 234 _get_next_token(char *npp,              /* string */
 235                 int token)              /* char to parse string for */
 236 {
 237     char  *cp;          /* char pointer */
 238     char  *np;          /* netpath pointer */
 239     char  *ep;          /* escape pointer */
 240
 241     if ((cp = strchr(npp, token)) == NULL) {
 242         return (NULL);
 243     }
 244     /*
 245      * did find a token, but it might be escaped.
 246      */
 247     if ((cp > npp) && (cp[-1] == '\\')) {
 248         /* if slash was also escaped, carry on, otherwise find next token */
 249         if ((cp > npp + 1) && (cp[-2] != '\\')) {
 250             /* shift r-o-s  onto the escaped token */
 251             strcpy(&cp[-1], cp);    /* XXX: overlapping string copy */
 252             /*
 253              * Do a recursive call.
 254              * We don't know how many escaped tokens there might be.
 255              */
 256             return (_get_next_token(cp, token));
 257         }
 258     }
 259
 260     *cp++ = '\0';               /* null-terminate token */
 261     /* get rid of any backslash escapes */
 262     ep = npp;
 263     while ((np = strchr(ep, '\\')) != 0) {
 264         if (np[1] == '\\')
 265             np++;
 266         strcpy(np, (ep = &np[1]));  /* XXX: overlapping string copy */
 267     }
 268     return (cp);                /* return ptr to r-o-s */
 269 }