1 /* $NetBSD: nlist_elf32.c,v 1.21 2000/06/14 17:25:03 cgd 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 /* If not included by nlist_elf64.c, ELFSIZE won't be defined. */ 38 #ifndef ELFSIZE 39 #define ELFSIZE 32 40 #endif 41 42 #include "namespace.h" 43 #include <sys/param.h> 44 #include <sys/mman.h> 45 #include <sys/stat.h> 46 #include <sys/file.h> 47 48 #include <assert.h> 49 #include <errno.h> 50 #include <stdio.h> 51 #include <string.h> 52 #include <unistd.h> 53 #include <a.out.h> /* for 'struct nlist' declaration */ 54 55 #include "nlist_private.h" 56 #if defined(NLIST_ELF32) || defined(NLIST_ELF64) 57 #include <sys/exec_elf.h> 58 #endif 59 60 #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \ 61 (defined(NLIST_ELF64) && (ELFSIZE == 64)) 62 63 /* No need to check for off < 0 because it is unsigned */ 64 #define check(off, size) (off + size > mappedsize) 65 #define BAD goto out 66 #define BADUNMAP goto unmap 67 68 int 69 ELFNAMEEND(__fdnlist)(fd, list) 70 int fd; 71 struct nlist *list; 72 { 73 struct stat st; 74 struct nlist *p; 75 char *mappedfile, *strtab; 76 size_t mappedsize; 77 Elf_Ehdr *ehdrp; 78 Elf_Shdr *shdrp, *symshdrp, *symstrshdrp; 79 Elf_Sym *symp; 80 Elf_Off shdr_off; 81 Elf_Word shdr_size; 82 #if (ELFSIZE == 32) 83 Elf32_Half nshdr; 84 #elif (ELFSIZE == 64) 85 Elf64_Half nshdr; 86 #endif 87 size_t i, nsyms; 88 int rv, nent; 89 90 _DIAGASSERT(fd != -1); 91 _DIAGASSERT(list != NULL); 92 93 rv = -1; 94 95 symshdrp = symstrshdrp = NULL; 96 97 /* 98 * If we can't fstat() the file, something bad is going on. 99 */ 100 if (fstat(fd, &st) < 0) 101 BAD; 102 103 /* 104 * Map the file in its entirety. 105 */ 106 if (st.st_size > SIZE_T_MAX) { 107 errno = EFBIG; 108 BAD; 109 } 110 mappedsize = (size_t)st.st_size; 111 mappedfile = mmap(NULL, mappedsize, PROT_READ, MAP_PRIVATE|MAP_FILE, 112 fd, (off_t)0); 113 if (mappedfile == (char *)-1) 114 BAD; 115 116 /* 117 * Make sure we can access the executable's header 118 * directly, and make sure the recognize the executable 119 * as an ELF binary. 120 */ 121 if (check(0, sizeof *ehdrp)) 122 BADUNMAP; 123 ehdrp = (Elf_Ehdr *)(void *)&mappedfile[0]; 124 125 if (memcmp(ehdrp->e_ident, ELFMAG, SELFMAG) != 0 || 126 ehdrp->e_ident[EI_CLASS] != ELFCLASS) 127 BADUNMAP; 128 129 switch (ehdrp->e_machine) { 130 ELFDEFNNAME(MACHDEP_ID_CASES) 131 132 default: 133 BADUNMAP; 134 } 135 136 /* 137 * Find the symbol list and string table. 138 */ 139 nshdr = ehdrp->e_shnum; 140 shdr_off = ehdrp->e_shoff; 141 shdr_size = ehdrp->e_shentsize * nshdr; 142 143 if (check(shdr_off, shdr_size) || 144 (sizeof *shdrp != ehdrp->e_shentsize)) 145 BADUNMAP; 146 shdrp = (Elf_Shdr *)(void *)&mappedfile[shdr_off]; 147 148 for (i = 0; i < nshdr; i++) { 149 if (shdrp[i].sh_type == SHT_SYMTAB) { 150 symshdrp = &shdrp[i]; 151 symstrshdrp = &shdrp[shdrp[i].sh_link]; 152 } 153 } 154 155 /* Make sure we're not stripped. */ 156 if (symshdrp == NULL || symshdrp->sh_offset == 0) 157 BADUNMAP; 158 159 /* Make sure the symbols and strings are safely mapped. */ 160 if (check(symshdrp->sh_offset, symshdrp->sh_size)) 161 BADUNMAP; 162 if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size)) 163 BADUNMAP; 164 165 symp = (Elf_Sym *)(void *)&mappedfile[symshdrp->sh_offset]; 166 nsyms = symshdrp->sh_size / sizeof(*symp); 167 strtab = &mappedfile[symstrshdrp->sh_offset]; 168 169 /* 170 * Clean out any left-over information for all valid entries. 171 * Type and value are defined to be 0 if not found; historical 172 * versions cleared other and desc as well. 173 * 174 * XXX Clearing anything other than n_type and n_value violates 175 * the semantics given in the man page. 176 */ 177 nent = 0; 178 for (p = list; !ISLAST(p); ++p) { 179 p->n_type = 0; 180 p->n_other = 0; 181 p->n_desc = 0; 182 p->n_value = 0; 183 ++nent; 184 } 185 186 for (i = 0; i < nsyms; i++) { 187 for (p = list; !ISLAST(p); ++p) { 188 const char *nlistname; 189 char *symtabname; 190 191 /* This may be incorrect */ 192 nlistname = p->n_un.n_name; 193 if (*nlistname == '_') 194 nlistname++; 195 196 symtabname = &strtab[symp[i].st_name]; 197 198 if (!strcmp(symtabname, nlistname)) { 199 /* 200 * Translate (roughly) from ELF to nlist 201 */ 202 p->n_value = symp[i].st_value; 203 switch (ELFDEFNNAME(ST_TYPE)(symp[i].st_info)) { 204 case STT_NOTYPE: 205 p->n_type = N_UNDF; 206 break; 207 case STT_OBJECT: 208 p->n_type = N_DATA; 209 break; 210 case STT_FUNC: 211 p->n_type = N_TEXT; 212 break; 213 case STT_FILE: 214 p->n_type = N_FN; 215 break; 216 default: 217 /* catch other enumerations for gcc */ 218 break; 219 } 220 if (ELFDEFNNAME(ST_BIND)(symp[i].st_info) != 221 STB_LOCAL) 222 p->n_type |= N_EXT; 223 p->n_desc = 0; /* XXX */ 224 p->n_other = 0; /* XXX */ 225 226 if (--nent <= 0) 227 goto done; 228 break; /* into next run of outer loop */ 229 } 230 } 231 } 232 233 done: 234 rv = nent; 235 unmap: 236 munmap(mappedfile, mappedsize); 237 out: 238 return (rv); 239 } 240 241 #endif 242