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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 #include <sys/cdefs.h> 39 #ifndef lint 40 __RCSID("$NetBSD: expand.c,v 1.4 2007/09/20 19:42:53 christos Exp $"); 41 #endif /* not lint */ 42 43 #include <ctype.h> 44 #include <string.h> 45 #include <sys/sysctl.h> 46 47 #ifdef DEBUG_EXPAND 48 #include <stdio.h> 49 #include <err.h> 50 #define xwarn warn 51 #define xerr err 52 size_t _rtld_expand_path(char *, size_t, const char *, const char *, 53 const char *); 54 #else 55 #include <sys/stat.h> 56 #include "rtld.h" 57 #endif 58 59 static const struct { 60 const char *name; 61 size_t namelen; 62 } bltn[] = { 63 #define ADD(a) { #a, sizeof(#a) - 1 }, 64 ADD(HWCAP) /* SSE, MMX, etc */ 65 ADD(ISALIST) /* XXX */ 66 ADD(ORIGIN) /* dirname argv[0] */ 67 ADD(OSNAME) /* uname -s */ 68 ADD(OSREL) /* uname -r */ 69 ADD(PLATFORM) /* uname -p */ 70 }; 71 72 static int mib[3][2] = { 73 { CTL_KERN, KERN_OSTYPE }, 74 { CTL_KERN, KERN_OSRELEASE }, 75 { CTL_HW, HW_MACHINE_ARCH }, 76 }; 77 78 static size_t 79 expand(char *buf, const char *execname, int what, size_t bl) 80 { 81 const char *p, *ep; 82 char *bp = buf; 83 size_t len; 84 char name[32]; 85 86 switch (what) { 87 case 0: /* HWCAP XXX: Not yet */ 88 case 1: /* ISALIST XXX: Not yet */ 89 return 0; 90 91 case 2: /* ORIGIN */ 92 if (execname == NULL) 93 xerr(1, "execname not specified in AUX vector"); 94 if ((ep = strrchr(p = execname, '/')) == NULL) 95 xerr(1, "bad execname `%s' in AUX vector", execname); 96 break; 97 98 case 3: /* OSNAME */ 99 case 4: /* OSREL */ 100 case 5: /* PLATFORM */ 101 len = sizeof(name); 102 if (sysctl(mib[what - 3], 2, name, &len, NULL, 0) == -1) { 103 xwarn("sysctl"); 104 return 0; 105 } 106 ep = (p = name) + len - 1; 107 break; 108 default: 109 return 0; 110 } 111 112 while (p != ep && bl) 113 *bp++ = *p++, bl--; 114 115 return bp - buf; 116 } 117 118 119 size_t 120 _rtld_expand_path(char *buf, size_t bufsize, const char *execname, 121 const char *bp, const char *ep) 122 { 123 size_t i, ds = bufsize; 124 char *dp = buf; 125 const char *p; 126 int br; 127 128 for (p = bp; p < ep;) { 129 if (*p == '$') { 130 br = *++p == '{'; 131 132 if (br) 133 p++; 134 135 for (i = 0; i < sizeof(bltn) / sizeof(bltn[0]); i++) { 136 size_t s = bltn[i].namelen; 137 const char *es = p + s; 138 139 if ((br && *es != '}') || 140 (!br && (es != ep && 141 isalpha((unsigned char)*es)))) 142 continue; 143 144 if (strncmp(bltn[i].name, p, s) == 0) { 145 size_t ls = expand(dp, execname, i, ds); 146 if (ls >= ds) 147 return bufsize; 148 ds -= ls; 149 dp += ls; 150 p = es + br; 151 goto done; 152 } 153 } 154 p -= br + 1; 155 156 } 157 *dp++ = *p++; 158 ds--; 159 done:; 160 } 161 *dp = '\0'; 162 return dp - buf; 163 } 164 165 #ifdef DEBUG_EXPAND 166 int 167 main(int argc, char *argv[]) 168 { 169 char buf[1024]; 170 size_t i; 171 172 for (i = 1; i < argc; i++) { 173 char *p = argv[i], *ep = argv[i] + strlen(p); 174 size_t n = _rtld_expand_path(buf, sizeof(buf), argv[0], p, ep); 175 printf("%s\n", buf); 176 } 177 return 0; 178 } 179 #endif 180