1 /* $OpenBSD: ksyms.c,v 1.25 2014/07/08 17:19:25 deraadt Exp $ */ 2 /* 3 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> 4 * Copyright (c) 2001 Artur Grabowski <art@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19 * THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/param.h> 29 #include <sys/buf.h> 30 #include <sys/exec.h> 31 #include <sys/systm.h> 32 #include <sys/uio.h> 33 #include <sys/malloc.h> 34 #include <sys/fcntl.h> 35 #include <sys/conf.h> 36 37 #ifdef _NLIST_DO_ELF 38 #include <sys/exec_elf.h> 39 #endif 40 41 extern char *esym; /* end of symbol table */ 42 #if defined(__sparc64__) || defined(__mips__) 43 extern char *ssym; /* end of kernel */ 44 #else 45 extern long end; /* end of kernel */ 46 #endif 47 48 static caddr_t ksym_head; 49 static caddr_t ksym_syms; 50 static size_t ksym_head_size; 51 static size_t ksym_syms_size; 52 53 void ksymsattach(int); 54 55 /* 56 * We assume __LDPGSZ is a multiple of PAGE_SIZE (it is) 57 */ 58 59 /*ARGSUSED*/ 60 void 61 ksymsattach(int num) 62 { 63 64 #if defined(__sparc64__) || defined(__mips__) 65 if (esym <= ssym) { 66 printf("/dev/ksyms: Symbol table not valid.\n"); 67 return; 68 } 69 #else 70 if (esym <= (char *)&end) { 71 printf("/dev/ksyms: Symbol table not valid.\n"); 72 return; 73 } 74 #endif 75 76 #ifdef _NLIST_DO_ELF 77 do { 78 #if defined(__sparc64__) || defined(__mips__) 79 caddr_t symtab = ssym; 80 #else 81 caddr_t symtab = (caddr_t)&end; 82 #endif 83 Elf_Ehdr *elf; 84 Elf_Shdr *shdr; 85 int i; 86 87 elf = (Elf_Ehdr *)symtab; 88 if (memcmp(elf->e_ident, ELFMAG, SELFMAG) != 0 || 89 elf->e_ident[EI_CLASS] != ELFCLASS || 90 elf->e_machine != ELF_TARG_MACH) 91 break; 92 93 shdr = (Elf_Shdr *)&symtab[elf->e_shoff]; 94 for (i = 0; i < elf->e_shnum; i++) { 95 if (shdr[i].sh_type == SHT_SYMTAB) { 96 break; 97 } 98 } 99 100 /* 101 * No symbol table found. 102 */ 103 if (i == elf->e_shnum) 104 break; 105 106 /* 107 * No additional header. 108 */ 109 ksym_head_size = 0; 110 ksym_syms = symtab; 111 ksym_syms_size = (size_t)(esym - symtab); 112 113 return; 114 } while (0); 115 #endif 116 } 117 118 /*ARGSUSED*/ 119 int 120 ksymsopen(dev_t dev, int flag, int mode, struct proc *p) 121 { 122 123 /* There are no non-zero minor devices */ 124 if (minor(dev) != 0) 125 return (ENXIO); 126 127 /* This device is read-only */ 128 if ((flag & FWRITE)) 129 return (EPERM); 130 131 /* ksym_syms must be initialized */ 132 if (ksym_syms == NULL) 133 return (ENXIO); 134 135 return (0); 136 } 137 138 /*ARGSUSED*/ 139 int 140 ksymsclose(dev_t dev, int flag, int mode, struct proc *p) 141 { 142 143 return (0); 144 } 145 146 /*ARGSUSED*/ 147 int 148 ksymsread(dev_t dev, struct uio *uio, int flags) 149 { 150 int error; 151 size_t len; 152 caddr_t v; 153 size_t off; 154 155 if (uio->uio_offset < 0) 156 return (EINVAL); 157 158 while (uio->uio_resid > 0) { 159 if (uio->uio_offset >= ksym_head_size + ksym_syms_size) 160 break; 161 162 if (uio->uio_offset < ksym_head_size) { 163 v = ksym_head + uio->uio_offset; 164 len = ksym_head_size - uio->uio_offset; 165 } else { 166 off = uio->uio_offset - ksym_head_size; 167 v = ksym_syms + off; 168 len = ksym_syms_size - off; 169 } 170 171 if (len > uio->uio_resid) 172 len = uio->uio_resid; 173 174 if ((error = uiomove(v, len, uio)) != 0) 175 return (error); 176 } 177 178 return (0); 179 } 180