Home | History | Annotate | Line # | Download | only in ld.elf_so
expand.c revision 1.5.26.1 
      1 /*	$NetBSD: expand.c,v 1.5.26.1 2013/06/23 06:28:49 tls 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 1.5.26.1 2013/06/23 06:28:49 tls 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
    173