1/* $NetBSD: expand.c,v 1.7 2023/01/04 01:37:00 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 1.7 2023/01/04 01:37:00 christos Exp $"); 34#endif /* not lint */ 35 36#include <ctype.h> 37#include <string.h> 38#include <sys/sysctl.h> 39 40#ifdef DEBUG_EXPAND 41#include <stdio.h> 42#include <err.h> 43#define xwarn warn 44#define xerr err 45size_t _rtld_expand_path(char *, size_t, const char *, const char *, 46 const char *); 47#else 48#include <sys/stat.h> 49#include "rtld.h" 50#endif 51 52static const struct { 53 const char *name; 54 size_t namelen; 55} bltn[] = { 56#define ADD(a) { #a, sizeof(#a) - 1 }, 57 ADD(HWCAP) /* SSE, MMX, etc */ 58 ADD(ISALIST) /* XXX */ 59 ADD(ORIGIN) /* dirname argv[0] */ 60 ADD(OSNAME) /* uname -s */ 61 ADD(OSREL) /* uname -r */ 62 ADD(PLATFORM) /* uname -p */ 63}; 64 65static int mib[3][2] = { 66 { CTL_KERN, KERN_OSTYPE }, 67 { CTL_KERN, KERN_OSRELEASE }, 68 { CTL_HW, HW_MACHINE_ARCH }, 69}; 70 71static size_t 72expand(char *buf, const char *execname, size_t what, size_t bl) 73{ 74 const char *p, *ep; 75 char *bp = buf; 76 size_t len; 77 char name[32]; 78 79 switch (what) { 80 case 0: /* HWCAP XXX: Not yet */ 81 case 1: /* ISALIST XXX: Not yet */ 82 return 0; 83 84 case 2: /* ORIGIN */ 85 if (execname == NULL) 86 xerr(1, "execname not specified in AUX vector"); 87 if ((ep = strrchr(p = execname, '/')) == NULL) 88 xerr(1, "bad execname `%s' in AUX vector", execname); 89 break; 90 91 case 3: /* OSNAME */ 92 case 4: /* OSREL */ 93 case 5: /* PLATFORM */ 94 len = sizeof(name); 95 if (sysctl(mib[what - 3], 2, name, &len, NULL, 0) == -1) { 96 xwarn("sysctl"); 97 return 0; 98 } 99 ep = (p = name) + len - 1; 100 break; 101 default: 102 return 0; 103 } 104 105 while (p != ep && bl) 106 *bp++ = *p++, bl--; 107 108 return bp - buf; 109} 110 111 112size_t 113_rtld_expand_path(char *buf, size_t bufsize, const char *execname, 114 const char *bp, const char *ep) 115{ 116 size_t i, ds = bufsize; 117 char *dp = buf; 118 const char *p; 119 int br; 120 121 for (p = bp; p < ep;) { 122 if (*p == '$') { 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--; 152done:; 153 } 154 *dp = '\0'; 155 return dp - buf; 156} 157 158#ifdef DEBUG_EXPAND 159int 160main(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 173