sod.c revision 1.27
1/* $OpenBSD: sod.c,v 1.27 2013/12/03 01:47:05 deraadt Exp $ */ 2 3/* 4 * Copyright (c) 1993 Paul Kranenburg 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Paul Kranenburg. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 * 32 */ 33 34#include <sys/types.h> 35#include <sys/mman.h> 36#include <machine/exec.h> 37#include <limits.h> 38#include <stdio.h> 39#include <fcntl.h> 40#include <nlist.h> 41#include <link.h> 42#include <limits.h> 43#include <string.h> 44#include <stdlib.h> 45#include <unistd.h> 46 47#include "syscall.h" 48#include "archdep.h" 49#include "path.h" 50#include "util.h" 51#include "sod.h" 52 53int _dl_hinthash(char *cp, int vmajor, int vminor); 54void _dl_maphints(void); 55 56/* 57 * Populate sod struct for dlopen's call to map_object 58 */ 59void 60_dl_build_sod(const char *name, struct sod *sodp) 61{ 62 unsigned int tuplet; 63 int major, minor; 64 char *realname, *tok, *etok, *cp; 65 66 /* default is an absolute or relative path */ 67 sodp->sod_name = (long)_dl_strdup(name); /* strtok is destructive */ 68 sodp->sod_library = 0; 69 sodp->sod_major = sodp->sod_minor = 0; 70 71 /* does it look like /^lib/ ? */ 72 if (_dl_strncmp((char *)sodp->sod_name, "lib", 3) != 0) 73 goto backout; 74 75 /* is this a filename? */ 76 if (_dl_strchr((char *)sodp->sod_name, '/')) 77 goto backout; 78 79 /* skip over 'lib' */ 80 cp = (char *)sodp->sod_name + 3; 81 82 realname = cp; 83 84 /* dot guardian */ 85 if ((_dl_strchr(cp, '.') == NULL) || (*(cp+_dl_strlen(cp)-1) == '.')) 86 goto backout; 87 88 cp = _dl_strstr(cp, ".so"); 89 if (cp == NULL) 90 goto backout; 91 92 /* default */ 93 major = minor = -1; 94 95 /* loop through name - parse skipping name */ 96 for (tuplet = 0; (tok = strsep(&cp, ".")) != NULL; tuplet++) { 97 switch (tuplet) { 98 case 0: 99 /* empty tok, we already skipped to "\.so.*" */ 100 break; 101 case 1: 102 /* 'so' extension */ 103 break; 104 case 2: 105 /* major version extension */ 106 major = _dl_strtol(tok, &etok, 10); 107 if (*tok == '\0' || *etok != '\0') 108 goto backout; 109 break; 110 case 3: 111 /* minor version extension */ 112 minor = _dl_strtol(tok, &etok, 10); 113 if (*tok == '\0' || *etok != '\0') 114 goto backout; 115 break; 116 /* if we get here, it must be weird */ 117 default: 118 goto backout; 119 } 120 } 121 if (realname == NULL) 122 goto backout; 123 cp = (char *)sodp->sod_name; 124 sodp->sod_name = (long)_dl_strdup(realname); 125 _dl_free(cp); 126 sodp->sod_library = 1; 127 sodp->sod_major = major; 128 sodp->sod_minor = minor; 129 return; 130 131backout: 132 _dl_free((char *)sodp->sod_name); 133 sodp->sod_name = (long)_dl_strdup(name); 134} 135 136void 137_dl_set_sod(const char *path, struct sod *sod) 138{ 139 char *fname = _dl_strrchr(path, '/'); 140 141 if (fname != NULL) 142 _dl_build_sod(++fname, sod); 143 else 144 _dl_build_sod(path, sod); 145} 146 147static struct hints_header *hheader = NULL; 148static struct hints_bucket *hbuckets; 149static char *hstrtab; 150char **_dl_hint_search_path = NULL; 151 152#define HINTS_VALID (hheader != NULL && hheader != (struct hints_header *)-1) 153 154void 155_dl_maphints(void) 156{ 157 struct stat sb; 158 caddr_t addr = MAP_FAILED; 159 long hsize = 0; 160 int hfd; 161 162 if ((hfd = _dl_open(_PATH_LD_HINTS, O_RDONLY)) < 0) 163 goto bad_hints; 164 165 if (_dl_fstat(hfd, &sb) != 0 || !S_ISREG(sb.st_mode) || 166 sb.st_size < sizeof(struct hints_header) || sb.st_size > LONG_MAX) 167 goto bad_hints; 168 169 hsize = (long)sb.st_size; 170 addr = (void *)_dl_mmap(0, hsize, PROT_READ, MAP_PRIVATE, hfd, 0); 171 if (_dl_mmap_error(addr)) 172 goto bad_hints; 173 174 hheader = (struct hints_header *)addr; 175 if (HH_BADMAG(*hheader) || hheader->hh_ehints > hsize) 176 goto bad_hints; 177 178 if (hheader->hh_version != LD_HINTS_VERSION_1 && 179 hheader->hh_version != LD_HINTS_VERSION_2) 180 goto bad_hints; 181 182 hbuckets = (struct hints_bucket *)(addr + hheader->hh_hashtab); 183 hstrtab = (char *)(addr + hheader->hh_strtab); 184 if (hheader->hh_version >= LD_HINTS_VERSION_2) 185 _dl_hint_search_path = _dl_split_path(hstrtab + hheader->hh_dirlist); 186 187 /* close the file descriptor, leaving the hints mapped */ 188 _dl_close(hfd); 189 190 return; 191 192bad_hints: 193 if (!_dl_mmap_error(addr)) 194 _dl_munmap(addr, hsize); 195 if (hfd != -1) 196 _dl_close(hfd); 197 hheader = (struct hints_header *)-1; 198} 199 200char * 201_dl_findhint(char *name, int major, int minor, char *preferred_path) 202{ 203 struct hints_bucket *bp; 204 205 /* 206 * If not mapped, and we have not tried before, try to map the 207 * hints, if previous attempts failed hheader is -1 and we 208 * do not wish to retry it. 209 */ 210 if (hheader == NULL) 211 _dl_maphints(); 212 213 /* if it failed to map, return failure */ 214 if (!(HINTS_VALID)) 215 return NULL; 216 217 if (hheader->hh_nbucket == 0) 218 return NULL; 219 220 bp = hbuckets + (_dl_hinthash(name, major, minor) % hheader->hh_nbucket); 221 222 while (1) { 223 /* Sanity check */ 224 if (bp->hi_namex >= hheader->hh_strtab_sz) { 225 _dl_printf("Bad name index: %#x\n", bp->hi_namex); 226 _dl_exit(7); 227 break; 228 } 229 if (bp->hi_pathx >= hheader->hh_strtab_sz) { 230 _dl_printf("Bad path index: %#x\n", bp->hi_pathx); 231 _dl_exit(7); 232 break; 233 } 234 235 if (_dl_strcmp(name, hstrtab + bp->hi_namex) == 0) { 236 /* It's `name', check version numbers */ 237 if (bp->hi_major == major && 238 (bp->hi_ndewey < 2 || bp->hi_minor >= minor)) { 239 if (preferred_path == NULL) { 240 return hstrtab + bp->hi_pathx; 241 } else { 242 char *path = hstrtab + bp->hi_pathx; 243 char *edir = _dl_strrchr(path, '/'); 244 245 if ((_dl_strncmp(preferred_path, path, 246 (edir - path)) == 0) && 247 (preferred_path[edir - path] == '\0')) 248 return path; 249 } 250 } 251 } 252 253 if (bp->hi_next == -1) 254 break; 255 256 /* Move on to next in bucket */ 257 bp = &hbuckets[bp->hi_next]; 258 } 259 260 /* No hints available for name */ 261 return NULL; 262} 263 264int 265_dl_hinthash(char *cp, int vmajor, int vminor) 266{ 267 int k = 0; 268 269 while (*cp) 270 k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff; 271 272 k = (((k << 1) + (k >> 14)) ^ (vmajor*257)) & 0x3fff; 273 if (hheader->hh_version == LD_HINTS_VERSION_1) 274 k = (((k << 1) + (k >> 14)) ^ (vminor*167)) & 0x3fff; 275 276 return k; 277} 278