1 /* $NetBSD: nlist_elf32.c,v 1.5 1996/10/03 04:55:31 cgd 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 <sys/param.h> 39 #include <sys/mman.h> 40 #include <sys/stat.h> 41 #include <sys/file.h> 42 43 #include <errno.h> 44 #include <stdio.h> 45 #include <string.h> 46 #include <unistd.h> 47 #include <a.out.h> /* for 'struct nlist' declaration */ 48 49 #include "nlist_private.h" 50 #if defined(NLIST_ELF32) || defined(NLIST_ELF64) 51 #include <sys/exec_elf.h> 52 #endif 53 54 #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \ 55 (defined(NLIST_ELF64) && (ELFSIZE == 64)) 56 57 #define CONCAT(x,y) __CONCAT(x,y) 58 #define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 59 #define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 60 #define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 61 #define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 62 63 #define check(off, size) ((off < 0) || (off + size > mappedsize)) 64 #define BAD do { rv = -1; goto out; } while (0) 65 #define BADUNMAP do { rv = -1; goto unmap; } while (0) 66 67 int 68 ELFNAMEEND(__fdnlist)(fd, list) 69 register int fd; 70 register struct nlist *list; 71 { 72 struct stat st; 73 struct nlist *p; 74 char *mappedfile, *strtab; 75 size_t mappedsize; 76 Elf_Ehdr *ehdrp; 77 Elf_Shdr *shdrp, *symshdrp, *symstrshdrp; 78 Elf_Sym *symp; 79 Elf_Off shdr_off; 80 Elf_Word shdr_size; 81 #if (ELFSIZE == 32) 82 Elf32_Half nshdr; 83 #elif (ELFSIZE == 64) 84 Elf64_Half nshdr; 85 #endif 86 unsigned long i, nsyms; 87 int rv, nent; 88 89 rv = -1; 90 91 /* 92 * If we can't fstat() the file, something bad is going on. 93 */ 94 if (fstat(fd, &st) < 0) 95 BAD; 96 97 /* 98 * Map the file in its entirety. 99 */ 100 if (st.st_size > SIZE_T_MAX) { 101 errno = EFBIG; 102 BAD; 103 } 104 mappedsize = st.st_size; 105 mappedfile = mmap(NULL, mappedsize, PROT_READ, 0, fd, 0); 106 if (mappedfile == (char *)-1) 107 BAD; 108 109 /* 110 * Make sure we can access the executable's header 111 * directly, and make sure the recognize the executable 112 * as an ELF binary. 113 */ 114 if (check(0, sizeof *ehdrp)) 115 BADUNMAP; 116 ehdrp = (Elf_Ehdr *)&mappedfile[0]; 117 118 if (bcmp(ehdrp->e_ident, Elf_e_ident, Elf_e_siz)) 119 BADUNMAP; 120 121 switch (ehdrp->e_machine) { 122 ELFDEFNNAME(MACHDEP_ID_CASES) 123 124 default: 125 BADUNMAP; 126 } 127 128 /* 129 * Find the symbol list and string table. 130 */ 131 nshdr = ehdrp->e_shnum; 132 shdr_off = ehdrp->e_shoff; 133 shdr_size = ehdrp->e_shentsize * nshdr; 134 135 if (check(shdr_off, shdr_size) || 136 (sizeof *shdrp != ehdrp->e_shentsize)) 137 BADUNMAP; 138 shdrp = (Elf_Shdr *)&mappedfile[shdr_off]; 139 140 for (i = 0; i < nshdr; i++) { 141 if (shdrp[i].sh_type == Elf_sht_symtab) { 142 symshdrp = &shdrp[i]; 143 symstrshdrp = &shdrp[shdrp[i].sh_link]; 144 } 145 } 146 147 /* Make sure we're not stripped. */ 148 if (symshdrp->sh_offset == 0) 149 BADUNMAP; 150 151 /* Make sure the symbols and strings are safely mapped. */ 152 if (check(symshdrp->sh_offset, symshdrp->sh_size)) 153 BADUNMAP; 154 if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size)) 155 BADUNMAP; 156 157 symp = (Elf_Sym *)&mappedfile[symshdrp->sh_offset]; 158 nsyms = symshdrp->sh_size / sizeof(*symp); 159 strtab = &mappedfile[symstrshdrp->sh_offset]; 160 161 /* 162 * Clean out any left-over information for all valid entries. 163 * Type and value are defined to be 0 if not found; historical 164 * versions cleared other and desc as well. 165 * 166 * XXX Clearing anything other than n_type and n_value violates 167 * the semantics given in the man page. 168 */ 169 nent = 0; 170 for (p = list; !ISLAST(p); ++p) { 171 p->n_type = 0; 172 p->n_other = 0; 173 p->n_desc = 0; 174 p->n_value = 0; 175 ++nent; 176 } 177 178 for (i = 0; i < nsyms; i++) { 179 for (p = list; !ISLAST(p); ++p) { 180 char *nlistname; 181 char *symtabname; 182 183 /* This may be incorrect */ 184 nlistname = p->n_un.n_name; 185 if (*nlistname == '_') 186 nlistname++; 187 188 symtabname = &strtab[symp[i].st_name]; 189 190 if (!strcmp(symtabname, nlistname)) { 191 /* 192 * Translate (roughly) from ELF to nlist 193 */ 194 p->n_value = symp[i].st_value; 195 switch(ELF_SYM_TYPE(symp[i].st_info)) { 196 case Elf_estt_notype: 197 p->n_type = N_UNDF; 198 break; 199 case Elf_estt_object: 200 p->n_type = N_DATA; 201 break; 202 case Elf_estt_func: 203 p->n_type = N_TEXT; 204 break; 205 case Elf_estt_file: 206 p->n_type = N_FN; 207 break; 208 } 209 if (ELF_SYM_BIND(symp[i].st_info) != 210 Elf_estb_local) 211 p->n_type |= N_EXT; 212 p->n_desc = 0; /* XXX */ 213 p->n_other = 0; /* XXX */ 214 215 if (--nent <= 0) 216 goto done; 217 break; /* into next run of outer loop */ 218 } 219 } 220 } 221 222 done: 223 rv = nent; 224 unmap: 225 munmap(mappedfile, mappedsize); 226 out: 227 return (rv); 228 } 229 230 #endif 231