libexec/ld.elf_so/expand.c

   1 /*      $NetBSD: expand.c,v 1.6 2013/05/06 08:02:20 skrll 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 1.6 2013/05/06 08:02:20 skrll 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 #if !defined(__minix)
  66 static int mib[3][2] = {
  67         { CTL_KERN, KERN_OSTYPE },
  68         { CTL_KERN, KERN_OSRELEASE },
  69         { CTL_HW, HW_MACHINE_ARCH },
  70 };
  71 #endif /* !defined(__minix) */
  72
  73 static size_t
  74 expand(char *buf, const char *execname, int what, size_t bl)
  75 {
  76         const char *p, *ep;
  77         char *bp = buf;
  78 #if !defined(__minix)
  79         size_t len;
  80         char name[32];
  81 #endif /* !defined(__minix) */
  82
  83         switch (what) {
  84         case 0: /* HWCAP XXX: Not yet */
  85         case 1: /* ISALIST XXX: Not yet */
  86                 return 0;
  87
  88         case 2: /* ORIGIN */
  89                 if (execname == NULL)
  90                         xerr(1, "execname not specified in AUX vector");
  91                 if ((ep = strrchr(p = execname, '/')) == NULL)
  92                         xerr(1, "bad execname `%s' in AUX vector", execname);
  93                 break;
  94
  95 #if !defined(__minix)
  96         case 3: /* OSNAME */
  97         case 4: /* OSREL */
  98         case 5: /* PLATFORM */
  99                 len = sizeof(name);
 100                 if (sysctl(mib[what - 3], 2, name, &len, NULL, 0) == -1) {
 101                         xwarn("sysctl");
 102                         return 0;
 103                 }
 104                 ep = (p = name) + len - 1;
 105                 break;
 106 #endif /* !defined(__minix) */
 107         default:
 108                 return 0;
 109         }
 110
 111         while (p != ep && bl)
 112                 *bp++ = *p++, bl--;
 113
 114         return bp - buf;
 115 }
 116
 117
 118 size_t
 119 _rtld_expand_path(char *buf, size_t bufsize, const char *execname,
 120     const char *bp, const char *ep)
 121 {
 122         size_t i, ds = bufsize;
 123         char *dp = buf;
 124         const char *p;
 125         int br;
 126
 127         for (p = bp; p < ep;) {
 128                 if (*p == '$') {
 129                         br = *++p == '{';
 130
 131                         if (br)
 132                                 p++;
 133
 134                         for (i = 0; i < sizeof(bltn) / sizeof(bltn[0]); i++) {
 135                                 size_t s = bltn[i].namelen;
 136                                 const char *es = p + s;
 137
 138                                 if ((br && *es != '}') ||
 139                                     (!br && (es != ep &&
 140                                         isalpha((unsigned char)*es))))
 141                                         continue;
 142
 143                                 if (strncmp(bltn[i].name, p, s) == 0) {
 144                                         size_t ls = expand(dp, execname, i, ds);
 145                                         if (ls >= ds)
 146                                                 return bufsize;
 147                                         ds -= ls;
 148                                         dp += ls;
 149                                         p = es + br;
 150                                         goto done;
 151                                 }
 152                         }
 153                         p -= br + 1;
 154
 155                 }
 156                 *dp++ = *p++;
 157                 ds--;
 158 done:;
 159         }
 160         *dp = '\0';
 161         return dp - buf;
 162 }
 163
 164 #ifdef DEBUG_EXPAND
 165 int
 166 main(int argc, char *argv[])
 167 {
 168         char buf[1024];
 169         size_t i;
 170
 171         for (i = 1; i < argc; i++) {
 172                 char *p = argv[i], *ep = argv[i] + strlen(p);
 173                 size_t n = _rtld_expand_path(buf, sizeof(buf), argv[0], p, ep);
 174                 printf("%s\n", buf);
 175         }
 176         return 0;
 177 }
 178 #endif