1 /* $NetBSD: nlist_elf32.c,v 1.7 1997/12/15 05:43:54 mrg 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 symshdrp = symstrshdrp = NULL; 92 93 /* 94 * If we can't fstat() the file, something bad is going on. 95 */ 96 if (fstat(fd, &st) < 0) 97 BAD; 98 99 /* 100 * Map the file in its entirety. 101 */ 102 if (st.st_size > SIZE_T_MAX) { 103 errno = EFBIG; 104 BAD; 105 } 106 mappedsize = st.st_size; 107 mappedfile = mmap(NULL, mappedsize, PROT_READ, MAP_COPY|MAP_FILE, 108 fd, 0); 109 if (mappedfile == (char *)-1) 110 BAD; 111 112 /* 113 * Make sure we can access the executable's header 114 * directly, and make sure the recognize the executable 115 * as an ELF binary. 116 */ 117 if (check(0, sizeof *ehdrp)) 118 BADUNMAP; 119 ehdrp = (Elf_Ehdr *)&mappedfile[0]; 120 121 if (bcmp(ehdrp->e_ident, Elf_e_ident, Elf_e_siz)) 122 BADUNMAP; 123 124 switch (ehdrp->e_machine) { 125 ELFDEFNNAME(MACHDEP_ID_CASES) 126 127 default: 128 BADUNMAP; 129 } 130 131 /* 132 * Find the symbol list and string table. 133 */ 134 nshdr = ehdrp->e_shnum; 135 shdr_off = ehdrp->e_shoff; 136 shdr_size = ehdrp->e_shentsize * nshdr; 137 138 if (check(shdr_off, shdr_size) || 139 (sizeof *shdrp != ehdrp->e_shentsize)) 140 BADUNMAP; 141 shdrp = (Elf_Shdr *)&mappedfile[shdr_off]; 142 143 for (i = 0; i < nshdr; i++) { 144 if (shdrp[i].sh_type == Elf_sht_symtab) { 145 symshdrp = &shdrp[i]; 146 symstrshdrp = &shdrp[shdrp[i].sh_link]; 147 } 148 } 149 150 /* Make sure we're not stripped. */ 151 if (symshdrp == NULL || symshdrp->sh_offset == 0) 152 BADUNMAP; 153 154 /* Make sure the symbols and strings are safely mapped. */ 155 if (check(symshdrp->sh_offset, symshdrp->sh_size)) 156 BADUNMAP; 157 if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size)) 158 BADUNMAP; 159 160 symp = (Elf_Sym *)&mappedfile[symshdrp->sh_offset]; 161 nsyms = symshdrp->sh_size / sizeof(*symp); 162 strtab = &mappedfile[symstrshdrp->sh_offset]; 163 164 /* 165 * Clean out any left-over information for all valid entries. 166 * Type and value are defined to be 0 if not found; historical 167 * versions cleared other and desc as well. 168 * 169 * XXX Clearing anything other than n_type and n_value violates 170 * the semantics given in the man page. 171 */ 172 nent = 0; 173 for (p = list; !ISLAST(p); ++p) { 174 p->n_type = 0; 175 p->n_other = 0; 176 p->n_desc = 0; 177 p->n_value = 0; 178 ++nent; 179 } 180 181 for (i = 0; i < nsyms; i++) { 182 for (p = list; !ISLAST(p); ++p) { 183 char *nlistname; 184 char *symtabname; 185 186 /* This may be incorrect */ 187 nlistname = p->n_un.n_name; 188 if (*nlistname == '_') 189 nlistname++; 190 191 symtabname = &strtab[symp[i].st_name]; 192 193 if (!strcmp(symtabname, nlistname)) { 194 /* 195 * Translate (roughly) from ELF to nlist 196 */ 197 p->n_value = symp[i].st_value; 198 switch(ELF_SYM_TYPE(symp[i].st_info)) { 199 case Elf_estt_notype: 200 p->n_type = N_UNDF; 201 break; 202 case Elf_estt_object: 203 p->n_type = N_DATA; 204 break; 205 case Elf_estt_func: 206 p->n_type = N_TEXT; 207 break; 208 case Elf_estt_file: 209 p->n_type = N_FN; 210 break; 211 default: 212 /* catch other enumerations for gcc */ 213 break; 214 } 215 if (ELF_SYM_BIND(symp[i].st_info) != 216 Elf_estb_local) 217 p->n_type |= N_EXT; 218 p->n_desc = 0; /* XXX */ 219 p->n_other = 0; /* XXX */ 220 221 if (--nent <= 0) 222 goto done; 223 break; /* into next run of outer loop */ 224 } 225 } 226 } 227 228 done: 229 rv = nent; 230 unmap: 231 munmap(mappedfile, mappedsize); 232 out: 233 return (rv); 234 } 235 236 #endif 237