1 /* $NetBSD: nlist_elf32.c,v 1.12 1998/11/13 10:26:19 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1996 Christopher G. Demetriou. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Christopher G. Demetriou 17 * for the NetBSD Project. 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 /* If not included by nlist_elf64.c, ELFSIZE won't be defined. */ 34 #ifndef ELFSIZE 35 #define ELFSIZE 32 36 #endif 37 38 #include "namespace.h" 39 #include <sys/param.h> 40 #include <sys/mman.h> 41 #include <sys/stat.h> 42 #include <sys/file.h> 43 44 #include <errno.h> 45 #include <stdio.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include <a.out.h> /* for 'struct nlist' declaration */ 49 50 #include "nlist_private.h" 51 #if defined(NLIST_ELF32) || defined(NLIST_ELF64) 52 #include <sys/exec_elf.h> 53 #endif 54 55 #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \ 56 (defined(NLIST_ELF64) && (ELFSIZE == 64)) 57 58 #define CONCAT(x,y) __CONCAT(x,y) 59 #define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 60 #define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 61 #define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 62 #define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 63 64 /* No need to check for off < 0 because it is unsigned */ 65 #define check(off, size) (off + size > mappedsize) 66 #define BAD goto out 67 #define BADUNMAP goto unmap 68 69 int 70 ELFNAMEEND(__fdnlist)(fd, list) 71 int fd; 72 struct nlist *list; 73 { 74 struct stat st; 75 struct nlist *p; 76 char *mappedfile, *strtab; 77 size_t mappedsize; 78 Elf_Ehdr *ehdrp; 79 Elf_Shdr *shdrp, *symshdrp, *symstrshdrp; 80 Elf_Sym *symp; 81 Elf_Off shdr_off; 82 Elf_Word shdr_size; 83 #if (ELFSIZE == 32) 84 Elf32_Half nshdr; 85 #elif (ELFSIZE == 64) 86 Elf64_Half nshdr; 87 #endif 88 size_t i, nsyms; 89 int rv, nent; 90 91 rv = -1; 92 93 symshdrp = symstrshdrp = NULL; 94 95 /* 96 * If we can't fstat() the file, something bad is going on. 97 */ 98 if (fstat(fd, &st) < 0) 99 BAD; 100 101 /* 102 * Map the file in its entirety. 103 */ 104 if (st.st_size > SIZE_T_MAX) { 105 errno = EFBIG; 106 BAD; 107 } 108 mappedsize = (size_t)st.st_size; 109 mappedfile = mmap(NULL, mappedsize, PROT_READ, MAP_COPY|MAP_FILE, 110 fd, (off_t)0); 111 if (mappedfile == (char *)-1) 112 BAD; 113 114 /* 115 * Make sure we can access the executable's header 116 * directly, and make sure the recognize the executable 117 * as an ELF binary. 118 */ 119 if (check(0, sizeof *ehdrp)) 120 BADUNMAP; 121 ehdrp = (Elf_Ehdr *)(void *)&mappedfile[0]; 122 123 if (memcmp(ehdrp->e_ident, Elf_e_ident, Elf_e_siz)) 124 BADUNMAP; 125 126 switch (ehdrp->e_machine) { 127 ELFDEFNNAME(MACHDEP_ID_CASES) 128 129 default: 130 BADUNMAP; 131 } 132 133 /* 134 * Find the symbol list and string table. 135 */ 136 nshdr = ehdrp->e_shnum; 137 shdr_off = ehdrp->e_shoff; 138 shdr_size = ehdrp->e_shentsize * nshdr; 139 140 if (check(shdr_off, shdr_size) || 141 (sizeof *shdrp != ehdrp->e_shentsize)) 142 BADUNMAP; 143 shdrp = (Elf_Shdr *)(void *)&mappedfile[shdr_off]; 144 145 for (i = 0; i < nshdr; i++) { 146 if (shdrp[i].sh_type == Elf_sht_symtab) { 147 symshdrp = &shdrp[i]; 148 symstrshdrp = &shdrp[shdrp[i].sh_link]; 149 } 150 } 151 152 /* Make sure we're not stripped. */ 153 if (symshdrp == NULL || symshdrp->sh_offset == 0) 154 BADUNMAP; 155 156 /* Make sure the symbols and strings are safely mapped. */ 157 if (check(symshdrp->sh_offset, symshdrp->sh_size)) 158 BADUNMAP; 159 if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size)) 160 BADUNMAP; 161 162 symp = (Elf_Sym *)(void *)&mappedfile[symshdrp->sh_offset]; 163 nsyms = symshdrp->sh_size / sizeof(*symp); 164 strtab = &mappedfile[symstrshdrp->sh_offset]; 165 166 /* 167 * Clean out any left-over information for all valid entries. 168 * Type and value are defined to be 0 if not found; historical 169 * versions cleared other and desc as well. 170 * 171 * XXX Clearing anything other than n_type and n_value violates 172 * the semantics given in the man page. 173 */ 174 nent = 0; 175 for (p = list; !ISLAST(p); ++p) { 176 p->n_type = 0; 177 p->n_other = 0; 178 p->n_desc = 0; 179 p->n_value = 0; 180 ++nent; 181 } 182 183 for (i = 0; i < nsyms; i++) { 184 for (p = list; !ISLAST(p); ++p) { 185 const char *nlistname; 186 char *symtabname; 187 188 /* This may be incorrect */ 189 nlistname = p->n_un.n_name; 190 if (*nlistname == '_') 191 nlistname++; 192 193 symtabname = &strtab[symp[i].st_name]; 194 195 if (!strcmp(symtabname, nlistname)) { 196 /* 197 * Translate (roughly) from ELF to nlist 198 */ 199 p->n_value = symp[i].st_value; 200 switch(ELF_SYM_TYPE(symp[i].st_info)) { 201 case Elf_estt_notype: 202 p->n_type = N_UNDF; 203 break; 204 case Elf_estt_object: 205 p->n_type = N_DATA; 206 break; 207 case Elf_estt_func: 208 p->n_type = N_TEXT; 209 break; 210 case Elf_estt_file: 211 p->n_type = N_FN; 212 break; 213 default: 214 /* catch other enumerations for gcc */ 215 break; 216 } 217 if (ELF_SYM_BIND(symp[i].st_info) != 218 Elf_estb_local) 219 p->n_type |= N_EXT; 220 p->n_desc = 0; /* XXX */ 221 p->n_other = 0; /* XXX */ 222 223 if (--nent <= 0) 224 goto done; 225 break; /* into next run of outer loop */ 226 } 227 } 228 } 229 230 done: 231 rv = nent; 232 unmap: 233 munmap(mappedfile, mappedsize); 234 out: 235 return (rv); 236 } 237 238 #endif 239