1 /* $OpenBSD: exec_elf.c,v 1.8 2003/06/28 04:55:07 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1999 Mats O Jansson. 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 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #ifndef LINT 28 static char rcsid[] = "$OpenBSD: exec_elf.c,v 1.8 2003/06/28 04:55:07 deraadt Exp $"; 29 #endif 30 31 #include <err.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <nlist.h> 35 #include <stdlib.h> 36 #include <stdio.h> 37 #include <unistd.h> 38 #include <sys/exec.h> 39 #include <sys/exec_elf.h> 40 #include <sys/types.h> 41 42 #include "ukc.h" 43 44 caddr_t ptr, rest, pre; 45 Elf_Ehdr elf_ex; 46 Elf_Phdr *elf_phdr; 47 Elf_Shdr *elf_shdr; 48 char *elf_total; 49 char *elf_shstrtab; 50 off_t elf_size; 51 52 caddr_t elf_adjust(caddr_t); 53 caddr_t elf_readjust(caddr_t); 54 int elf_check(char *); 55 void elf_loadkernel(char *); 56 void elf_savekernel(char *); 57 58 caddr_t 59 elf_adjust(caddr_t x) 60 { 61 int i; 62 Elf_Shdr *s; 63 unsigned long y = 0; 64 65 s = elf_shdr; 66 67 for (i = 0; i < elf_ex.e_shnum; i++) { 68 if (s[i].sh_addr == 0) 69 continue; 70 if (((unsigned long)x >= s[i].sh_addr) && 71 ((unsigned long)x < (s[i].sh_addr+s[i].sh_size))) { 72 y = (unsigned long)&elf_total[(unsigned long)x - 73 s[i].sh_addr + s[i].sh_offset]; 74 break; 75 } 76 } 77 78 return((caddr_t)y); 79 } 80 81 caddr_t 82 elf_readjust(caddr_t x) 83 { 84 int i; 85 Elf_Shdr *s; 86 unsigned long y = 0; 87 88 s = elf_shdr; 89 90 for (i = 0; i < elf_ex.e_shnum; i++) { 91 if (s[i].sh_addr == 0) 92 continue; 93 if (((x - elf_total) >= s[i].sh_offset) && 94 ((x - elf_total) <= (s[i].sh_offset + s[i].sh_size))) 95 y = (unsigned long)x - (unsigned long)elf_total + 96 (unsigned long)s[i].sh_addr - s[i].sh_offset; 97 } 98 99 return((caddr_t)y); 100 } 101 102 int 103 elf_check(char *file) 104 { 105 int fd, ret = 1; 106 107 if ((fd = open(file, O_RDONLY | O_EXLOCK, 0)) < 0) 108 return (0); 109 110 if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) 111 ret = 0; 112 113 if (ret) { 114 if (!IS_ELF(elf_ex)) 115 ret = 0; 116 } 117 118 close(fd); 119 return (ret); 120 } 121 122 void 123 elf_loadkernel(char *file) 124 { 125 int fd; 126 Elf_Phdr *p; 127 Elf_Shdr *s; 128 129 if ((fd = open(file, O_RDONLY | O_EXLOCK, 0)) < 0) 130 err(1, "%s", file); 131 132 if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) 133 errx(1, "can't read elf header"); 134 135 if (!IS_ELF(elf_ex)) 136 errx(1, "bad elf magic"); 137 138 elf_size = lseek(fd, 0L, SEEK_END); 139 (void)lseek(fd, 0L, SEEK_SET); 140 elf_total = malloc(elf_size); 141 142 if (read(fd, elf_total, elf_size) != elf_size) 143 errx(1, "can't read elf kernel"); 144 145 elf_phdr = (Elf_Phdr *)&elf_total[elf_ex.e_phoff]; 146 elf_shdr = (Elf_Shdr *)&elf_total[elf_ex.e_shoff]; 147 148 p = elf_phdr; 149 s = elf_shdr; 150 151 elf_shstrtab = &elf_total[elf_shdr[elf_ex.e_shstrndx].sh_offset]; 152 153 close(fd); 154 } 155 156 void 157 elf_savekernel(char *outfile) 158 { 159 int fd; 160 161 if ((fd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC, 0755)) < 0) 162 err(1, "%s", outfile); 163 164 if (write(fd, elf_total, elf_size) != elf_size) 165 errx(1, "can't write file %s", outfile); 166 167 close(fd); 168 } 169