libexec/ld.elf_so/expand.c

   1 /*      $NetBSD: expand.c,v 1.4 2007/09/20 19:42:53 christos Exp $      */
   2
   3 /*-
   4  * Copyright (c) 2007 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Christos Zoulas.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 #include <sys/cdefs.h>
  32 #ifndef lint
  33 __RCSID("$NetBSD: expand.c,v 1.4 2007/09/20 19:42:53 christos Exp $");
  34 #endif /* not lint */
  35
  36 #include <ctype.h>
  37 #include <string.h>
  38 #include <sys/sysctl.h>
  39
  40 #ifdef DEBUG_EXPAND
  41 #include <stdio.h>
  42 #include <err.h>
  43 #define xwarn warn
  44 #define xerr err
  45 size_t _rtld_expand_path(char *, size_t, const char *, const char *,
  46     const char *);
  47 #else
  48 #include <sys/stat.h>
  49 #include "rtld.h"
  50 #endif
  51
  52 static const struct {
  53         const char *name;
  54         size_t namelen;
  55 } bltn[] = {
  56 #define ADD(a)  { #a, sizeof(#a) - 1 },
  57         ADD(HWCAP)      /* SSE, MMX, etc */
  58         ADD(ISALIST)    /* XXX */
  59         ADD(ORIGIN)     /* dirname argv[0] */
  60         ADD(OSNAME)     /* uname -s */
  61         ADD(OSREL)      /* uname -r */
  62         ADD(PLATFORM)   /* uname -p */
  63 };
  64
  65 static int mib[3][2] = {
  66         { CTL_KERN, KERN_OSTYPE },
  67         { CTL_KERN, KERN_OSRELEASE },
  68         { CTL_HW, HW_MACHINE_ARCH },
  69 };
  70
  71 static size_t
  72 expand(char *buf, const char *execname, int what, size_t bl)
  73 {
  74         const char *p, *ep;
  75         char *bp = buf;
  76         size_t len;
  77         char name[32];
  78
  79         switch (what) {
  80         case 0: /* HWCAP XXX: Not yet */
  81         case 1: /* ISALIST XXX: Not yet */
  82                 return 0;
  83
  84         case 2: /* ORIGIN */
  85                 if (execname == NULL)
  86                         xerr(1, "execname not specified in AUX vector");
  87                 if ((ep = strrchr(p = execname, '/')) == NULL)
  88                         xerr(1, "bad execname `%s' in AUX vector", execname);
  89                 break;
  90
  91         case 3: /* OSNAME */
  92         case 4: /* OSREL */
  93         case 5: /* PLATFORM */
  94                 len = sizeof(name);
  95                 if (sysctl(mib[what - 3], 2, name, &len, NULL, 0) == -1) {
  96                         xwarn("sysctl");
  97                         return 0;
  98                 }
  99                 ep = (p = name) + len - 1;
 100                 break;
 101         default:
 102                 return 0;
 103         }
 104
 105         while (p != ep && bl)
 106                 *bp++ = *p++, bl--;
 107
 108         return bp - buf;
 109 }
 110
 111
 112 size_t
 113 _rtld_expand_path(char *buf, size_t bufsize, const char *execname,
 114     const char *bp, const char *ep)
 115 {
 116         size_t i, ds = bufsize;
 117         char *dp = buf;
 118         const char *p;
 119         int br;
 120
 121         for (p = bp; p < ep;) {
 122                 if (*p == '$') {
 123                         br = *++p == '{';
 124
 125                         if (br)
 126                                 p++;
 127
 128                         for (i = 0; i < sizeof(bltn) / sizeof(bltn[0]); i++) {
 129                                 size_t s = bltn[i].namelen;
 130                                 const char *es = p + s;
 131
 132                                 if ((br && *es != '}') ||
 133                                     (!br && (es != ep &&
 134                                         isalpha((unsigned char)*es))))
 135                                         continue;
 136
 137                                 if (strncmp(bltn[i].name, p, s) == 0) {
 138                                         size_t ls = expand(dp, execname, i, ds);
 139                                         if (ls >= ds)
 140                                                 return bufsize;
 141                                         ds -= ls;
 142                                         dp += ls;
 143                                         p = es + br;
 144                                         goto done;
 145                                 }
 146                         }
 147                         p -= br + 1;
 148
 149                 }
 150                 *dp++ = *p++;
 151                 ds--;
 152 done:;
 153         }
 154         *dp = '\0';
 155         return dp - buf;
 156 }
 157
 158 #ifdef DEBUG_EXPAND
 159 int
 160 main(int argc, char *argv[])
 161 {
 162         char buf[1024];
 163         size_t i;
 164
 165         for (i = 1; i < argc; i++) {
 166                 char *p = argv[i], *ep = argv[i] + strlen(p);
 167                 size_t n = _rtld_expand_path(buf, sizeof(buf), argv[0], p, ep);
 168                 printf("%s\n", buf);
 169         }
 170         return 0;
 171 }
 172 #endif