1 /* $NetBSD: nlist_elf32.c,v 1.39 2016/02/26 17:12:53 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1996 Christopher G. Demetriou 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 for the 18 * NetBSD Project. See http://www.NetBSD.org/ for 19 * information about NetBSD. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>> 35 */ 36 37 #include <sys/cdefs.h> 38 #if defined(LIBC_SCCS) && !defined(lint) 39 __RCSID("$NetBSD: nlist_elf32.c,v 1.39 2016/02/26 17:12:53 christos Exp $"); 40 #endif /* LIBC_SCCS and not lint */ 41 42 /* If not included by nlist_elf64.c, ELFSIZE won't be defined. */ 43 #ifndef ELFSIZE 44 #define ELFSIZE 32 45 #endif 46 47 #include "namespace.h" 48 #include <sys/param.h> 49 #include <sys/mman.h> 50 #include <sys/stat.h> 51 #include <sys/file.h> 52 #include <sys/ioctl.h> 53 54 #include <assert.h> 55 #include <errno.h> 56 #include <stdio.h> 57 #include <string.h> 58 #include <unistd.h> 59 #include <nlist.h> 60 61 #include "nlist_private.h" 62 #if defined(NLIST_ELF32) || defined(NLIST_ELF64) 63 #include <sys/exec_elf.h> 64 #endif 65 66 #include <sys/ksyms.h> /* after sys/exec_elf.h */ 67 68 #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \ 69 (defined(NLIST_ELF64) && (ELFSIZE == 64)) 70 71 /* No need to check for off < 0 because it is unsigned */ 72 #define check(off, size) (off + size > mappedsize) 73 #define BAD goto out 74 #define BADUNMAP goto unmap 75 76 int 77 ELFNAMEEND(__fdnlist)(int fd, struct nlist *list) 78 { 79 struct stat st; 80 Elf_Ehdr ehdr; 81 #if defined(_LP64) || ELFSIZE == 32 || defined(ELF64_MACHDEP_ID) 82 #if (ELFSIZE == 32) 83 Elf32_Half nshdr; 84 #elif (ELFSIZE == 64) 85 Elf64_Word nshdr; 86 #endif 87 /* Only support 64+32 mode on LP64 and those that have defined */ 88 /* ELF64_MACHDEP_ID, otherwise no support for 64 mode on ILP32 */ 89 Elf_Ehdr *ehdrp; 90 Elf_Shdr *shdrp, *symshdrp, *symstrshdrp; 91 Elf_Sym *symp; 92 Elf_Off shdr_off; 93 Elf_Word shdr_size; 94 struct nlist *p; 95 char *mappedfile, *strtab; 96 size_t mappedsize, nsyms; 97 int nent; 98 #endif 99 int rv; 100 size_t i; 101 102 _DIAGASSERT(fd != -1); 103 _DIAGASSERT(list != NULL); 104 105 rv = -1; 106 107 /* 108 * If we can't fstat() the file, something bad is going on. 109 */ 110 if (fstat(fd, &st) < 0) 111 BAD; 112 113 /* 114 * Map the file in its entirety. 115 */ 116 if ((uintmax_t)st.st_size > (uintmax_t)SIZE_T_MAX) { 117 errno = EFBIG; 118 BAD; 119 } 120 121 /* 122 * Read the elf header of the file. 123 */ 124 if ((ssize_t)(i = pread(fd, &ehdr, sizeof(Elf_Ehdr), (off_t)0)) == -1) 125 BAD; 126 127 /* 128 * Check that the elf header is correct. 129 */ 130 if (i != sizeof(Elf_Ehdr)) 131 BAD; 132 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 || 133 ehdr.e_ident[EI_CLASS] != ELFCLASS) 134 BAD; 135 136 switch (ehdr.e_machine) { 137 ELFDEFNNAME(MACHDEP_ID_CASES) 138 139 default: 140 BAD; 141 } 142 #if defined(_LP64) || ELFSIZE == 32 || defined(ELF64_MACHDEP_ID) 143 symshdrp = symstrshdrp = NULL; 144 145 /* Only support 64+32 mode on LP64 and those that have defined */ 146 /* ELF64_MACHDEP_ID, otherwise no support for 64 mode on ILP32 */ 147 if (S_ISCHR(st.st_mode)) { 148 const char *nlistname; 149 Elf_Sym sym; 150 151 /* 152 * Character device; assume /dev/ksyms. 153 */ 154 nent = 0; 155 for (p = list; !ISLAST(p); ++p) { 156 struct ksyms_gsymbol kg; 157 int error; 158 159 p->n_other = 0; 160 p->n_desc = 0; 161 nlistname = N_NAME(p); 162 if (*nlistname == '_') 163 nlistname++; 164 165 memset(&kg, 0, sizeof(kg)); 166 kg.kg_name = nlistname; 167 #ifdef OKIOCGSYMBOL 168 struct ksyms_ogsymbol okg; 169 error = ioctl(fd, KIOCGSYMBOL, &kg); 170 if (error == 0) { 171 sym = kg.kg_sym; 172 } else if (error && errno == ENOTTY) { 173 memset(&okg, 0, sizeof(okg)); 174 okg.kg_name = nlistname; 175 okg.kg_sym = &sym; 176 error = ioctl(fd, OKIOCGSYMBOL, &okg); 177 } 178 #else 179 kg.kg_sym = &sym; 180 error = ioctl(fd, KIOCGSYMBOL, &kg); 181 #endif 182 if (error == 0 183 #if !defined(_LP64) && ELFSIZE == 64 184 #if __mips__ 185 && (intptr_t)sym.st_value == (intmax_t)sym.st_value 186 #else 187 && (uintptr_t)sym.st_value == sym.st_value 188 #endif 189 #endif 190 && /*CONSTCOND*/1) { 191 p->n_value = (uintptr_t)sym.st_value; 192 switch (ELF_ST_TYPE(sym.st_info)) { 193 case STT_NOTYPE: 194 p->n_type = N_UNDF; 195 break; 196 case STT_COMMON: 197 case STT_OBJECT: 198 p->n_type = N_DATA; 199 break; 200 case STT_FUNC: 201 p->n_type = N_TEXT; 202 break; 203 case STT_FILE: 204 p->n_type = N_FN; 205 break; 206 default: 207 p->n_type = 0; 208 /* catch other enumerations for gcc */ 209 break; 210 } 211 if (ELF_ST_BIND(sym.st_info) != STB_LOCAL) 212 p->n_type |= N_EXT; 213 } else { 214 nent++; 215 p->n_value = 0; 216 p->n_type = 0; 217 } 218 } 219 return nent; 220 } 221 222 mappedsize = (size_t)st.st_size; 223 mappedfile = mmap(NULL, mappedsize, PROT_READ, MAP_PRIVATE|MAP_FILE, 224 fd, (off_t)0); 225 if (mappedfile == (char *)-1) 226 BAD; 227 228 /* 229 * Make sure we can access the executable's header 230 * directly, and make sure the recognize the executable 231 * as an ELF binary. 232 */ 233 if (check(0, sizeof *ehdrp)) 234 BADUNMAP; 235 ehdrp = (Elf_Ehdr *)(void *)&mappedfile[0]; 236 237 /* 238 * Find the symbol list and string table. 239 */ 240 nshdr = ehdrp->e_shnum; 241 shdr_off = ehdrp->e_shoff; 242 shdr_size = ehdrp->e_shentsize * nshdr; 243 244 if (check(shdr_off, shdr_size) || 245 (sizeof *shdrp != ehdrp->e_shentsize)) 246 BADUNMAP; 247 shdrp = (void *)&mappedfile[(size_t)shdr_off]; 248 249 for (i = 0; i < nshdr; i++) { 250 if (shdrp[i].sh_type == SHT_SYMTAB) { 251 symshdrp = &shdrp[i]; 252 symstrshdrp = &shdrp[shdrp[i].sh_link]; 253 } 254 } 255 256 /* Make sure we're not stripped. */ 257 if (symshdrp == NULL || symshdrp->sh_offset == 0) 258 BADUNMAP; 259 260 /* Make sure the symbols and strings are safely mapped. */ 261 if (check(symshdrp->sh_offset, symshdrp->sh_size)) 262 BADUNMAP; 263 if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size)) 264 BADUNMAP; 265 266 symp = (void *)&mappedfile[(size_t)symshdrp->sh_offset]; 267 nsyms = (size_t)(symshdrp->sh_size / sizeof(*symp)); 268 strtab = &mappedfile[(size_t)symstrshdrp->sh_offset]; 269 270 /* 271 * Clean out any left-over information for all valid entries. 272 * Type and value are defined to be 0 if not found; historical 273 * versions cleared other and desc as well. 274 * 275 * XXX Clearing anything other than n_type and n_value violates 276 * the semantics given in the man page. 277 */ 278 nent = 0; 279 for (p = list; !ISLAST(p); ++p) { 280 p->n_type = 0; 281 p->n_other = 0; 282 p->n_desc = 0; 283 p->n_value = 0; 284 ++nent; 285 } 286 287 for (i = 0; i < nsyms; i++) { 288 for (p = list; !ISLAST(p); ++p) { 289 const char *nlistname; 290 char *symtabname; 291 292 /* This may be incorrect */ 293 nlistname = N_NAME(p); 294 if (*nlistname == '_') 295 nlistname++; 296 297 symtabname = &strtab[symp[i].st_name]; 298 299 if (!strcmp(symtabname, nlistname)) { 300 /* 301 * Translate (roughly) from ELF to nlist 302 */ 303 p->n_value = (uintptr_t)symp[i].st_value; 304 switch (ELF_ST_TYPE(symp[i].st_info)) { 305 case STT_NOTYPE: 306 p->n_type = N_UNDF; 307 break; 308 case STT_OBJECT: 309 case STT_COMMON: 310 p->n_type = N_DATA; 311 break; 312 case STT_FUNC: 313 p->n_type = N_TEXT; 314 break; 315 case STT_FILE: 316 p->n_type = N_FN; 317 break; 318 default: 319 /* catch other enumerations for gcc */ 320 break; 321 } 322 if (ELF_ST_BIND(symp[i].st_info) != STB_LOCAL) 323 p->n_type |= N_EXT; 324 p->n_desc = 0; /* XXX */ 325 p->n_other = 0; /* XXX */ 326 327 if (--nent <= 0) 328 goto done; 329 break; /* into next run of outer loop */ 330 } 331 } 332 } 333 334 done: 335 rv = nent; 336 unmap: 337 munmap(mappedfile, mappedsize); 338 #endif /* _LP64 || ELFSIZE == 32 || ELF64_MACHDEP_ID */ 339 out: 340 return (rv); 341 } 342 343 #endif 344
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