elf.c revision 1.2
1 /* $NetBSD: elf.c,v 1.2 2001/10/11 07:07:42 leo Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Leo Weppelman. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <stdio.h> 40 #include <unistd.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <sys/types.h> 44 45 #ifdef TOSTOOLS 46 #include "exec_elf.h" 47 #else 48 #include <sys/exec_elf.h> 49 #endif 50 #include "tosdefs.h" 51 #include "kparamb.h" 52 #include "libtos.h" 53 #include "cread.h" 54 55 /* 56 * Load an elf image. 57 * Exit codes: 58 * -1 : Not an ELF file. 59 * 0 : OK 60 * error# : Error during load (*errp might contain error string). 61 */ 62 #define ELFMAGIC ((ELFMAG0 << 24) | (ELFMAG1 << 16) | \ 63 (ELFMAG2 << 8) | ELFMAG3) 64 65 int 66 elf_load(fd, od, errp, loadsyms) 67 int fd; 68 osdsc_t *od; 69 char **errp; 70 int loadsyms; 71 { 72 int i,j; 73 int err; 74 Elf32_Ehdr ehdr; 75 Elf32_Phdr *phdrs; 76 Elf32_Word symsize, symstart; 77 long kernsize; 78 79 *errp = NULL; 80 lseek(fd, (off_t)0, SEEK_SET); 81 if (read(fd, (char *)&ehdr, sizeof(ehdr)) != sizeof(ehdr)) 82 return -1; 83 84 if (*((u_int *)ehdr.e_ident) != ELFMAGIC) 85 return -1; 86 87 /* 88 * calculate highest used address 89 */ 90 i = ehdr.e_phnum * sizeof(Elf32_Phdr); 91 err = 1; 92 if ((phdrs = (Elf32_Phdr *)malloc(i)) == NULL) 93 goto error; 94 err = 2; 95 if (read(fd, phdrs, i) != i) 96 goto error; 97 98 kernsize = 0; 99 for (i = 0; i < ehdr.e_phnum; i++) { 100 Elf32_Word sum; 101 102 sum = phdrs[i].p_vaddr + phdrs[i].p_memsz; 103 if ((phdrs[i].p_flags & (PF_W|PF_X)) && (sum > kernsize)) 104 kernsize = sum; 105 } 106 107 /* 108 * look for symbols and calculate the size 109 * XXX: This increases the load time by a factor 2 for gzipped 110 * images! 111 */ 112 symsize = 0; 113 symstart = 0; 114 if (loadsyms) { 115 i = ehdr.e_shnum + 1; 116 err = 3; 117 if (lseek(fd, (off_t)ehdr.e_shoff, SEEK_SET) != ehdr.e_shoff) 118 goto error; 119 while (--i) { 120 Elf32_Shdr shdr; 121 122 err = 4; 123 if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr)) 124 goto error; 125 if ((shdr.sh_type == SHT_SYMTAB) || (shdr.sh_type == SHT_STRTAB)) 126 symsize += shdr.sh_size; 127 } 128 } 129 130 if (symsize) { 131 symstart = kernsize; 132 kernsize += symsize + sizeof(ehdr) + ehdr.e_shnum*sizeof(Elf32_Shdr); 133 } 134 135 /* 136 * Extract various sizes from the kernel executable 137 */ 138 od->k_esym = symsize ? kernsize : 0; 139 od->ksize = kernsize; 140 od->kentry = ehdr.e_entry; 141 142 err = 5; 143 if ((od->kstart = (u_char *)malloc(od->ksize)) == NULL) 144 goto error; 145 146 /* 147 * Read text & data, clear bss 148 */ 149 for (i = 0; i < ehdr.e_phnum; i++) { 150 u_char *p; 151 Elf32_Phdr *php = &phdrs[i]; 152 153 if (php->p_flags & (PF_W|PF_X)) { 154 err = 6; 155 if (lseek(fd, (off_t)php->p_offset, SEEK_SET) != php->p_offset) 156 goto error; 157 p = (u_char *)(od->kstart) + php->p_vaddr; 158 err = 7; 159 if (read(fd, p, php->p_filesz) != php->p_filesz) 160 goto error; 161 if (php->p_memsz > php->p_filesz) 162 memset(p + php->p_filesz, 0, php->p_memsz - php->p_filesz); 163 } 164 } 165 166 /* 167 * Read symbols and strings 168 */ 169 if (symsize) { 170 u_char *p, *symtab; 171 int nhdrs; 172 Elf32_Shdr *shp; 173 174 symtab = od->kstart + symstart; 175 176 p = symtab + sizeof(ehdr); 177 nhdrs = ehdr.e_shnum; 178 err = 8; 179 if (lseek(fd, (off_t)ehdr.e_shoff, SEEK_SET) != ehdr.e_shoff) 180 goto error; 181 err = 9; 182 if (read(fd, p, nhdrs * sizeof(*shp)) != nhdrs * sizeof(*shp)) 183 goto error; 184 shp = (Elf32_Shdr*)p; 185 p += nhdrs * sizeof(*shp); 186 for (i = 0; i < nhdrs; i++) { 187 if (shp[i].sh_type == SHT_SYMTAB) { 188 if (shp[i].sh_offset == 0) 189 continue; 190 /* Got the symbol table. */ 191 err = 10; 192 if (lseek(fd, (off_t)shp[i].sh_offset, SEEK_SET) != 193 shp[i].sh_offset) 194 goto error; 195 err = 11; 196 if (read(fd, p, shp[i].sh_size) != shp[i].sh_size) 197 goto error; 198 shp[i].sh_offset = p - symtab; 199 /* Find the string table to go with it. */ 200 j = shp[i].sh_link; 201 if (shp[j].sh_offset == 0) 202 continue; 203 p += shp[i].sh_size; 204 err = 12; 205 if (lseek(fd, (off_t)shp[j].sh_offset, SEEK_SET) != 206 shp[j].sh_offset) 207 goto error; 208 err = 13; 209 if (read(fd, p, shp[j].sh_size) != shp[j].sh_size) 210 goto error; 211 shp[j].sh_offset = p - symtab; 212 /* There should only be one symbol table. */ 213 break; 214 } 215 } 216 ehdr.e_shoff = sizeof(ehdr); 217 bcopy(&ehdr, symtab, sizeof(ehdr)); 218 } 219 return 0; 220 221 error: 222 #ifdef TOSTOOLS 223 { 224 static char *errs[] = { 225 /* 1 */ "Cannot malloc Elf phdr storage space", 226 /* 2 */ "Cannot read Elf32_Phdrs", 227 /* 3 */ "Cannot seek to e_shoff location", 228 /* 4 */ "Cannot read Elf32_shdr", 229 /* 5 */ "Cannot malloc kernel image space", 230 /* 6 */ "Seek error while reading text segment\n", 231 /* 7 */ "Read error in text segment\n", 232 /* 8 */ "Error seeking to section headers", 233 /* 9 */ "Error reading section headers", 234 /* 10 */ "Error seeking to symbols", 235 /* 11 */ "Error reading symbols", 236 /* 12 */ "Error seeking to string table", 237 /* 13 */ "Error reading strings" 238 }; 239 *errp = errs[err]; 240 } 241 #endif /* TOSTOOLS */ 242 243 return err; 244 } 245
Indexes created Wed Oct 01 19:09:53 GMT 2025