1 /*- 2 * Copyright (c) 2008, Juniper Networks, Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the author nor the names of any co-contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/endian.h> 34 #include <sys/kerneldump.h> 35 #include <sys/mman.h> 36 37 #include <vm/vm.h> 38 39 #include <db.h> 40 #include <elf.h> 41 #include <limits.h> 42 #include <kvm.h> 43 #include <stdlib.h> 44 #include <string.h> 45 46 #include "kvm_private.h" 47 48 struct vmstate { 49 void *map; 50 size_t mapsz; 51 size_t dmphdrsz; 52 Elf32_Ehdr *eh; 53 Elf32_Phdr *ph; 54 }; 55 56 static int 57 valid_elf_header(Elf32_Ehdr *eh) 58 { 59 60 if (!IS_ELF(*eh)) 61 return (0); 62 if (eh->e_ident[EI_CLASS] != ELFCLASS32) 63 return (0); 64 if (eh->e_ident[EI_DATA] != ELFDATA2MSB) 65 return (0); 66 if (eh->e_ident[EI_VERSION] != EV_CURRENT) 67 return (0); 68 if (eh->e_ident[EI_OSABI] != ELFOSABI_STANDALONE) 69 return (0); 70 if (be16toh(eh->e_type) != ET_CORE) 71 return (0); 72 if (be16toh(eh->e_machine) != EM_PPC) 73 return (0); 74 /* Can't think of anything else to check... */ 75 return (1); 76 } 77 78 static size_t 79 dump_header_size(struct kerneldumpheader *dh) 80 { 81 82 if (strcmp(dh->magic, KERNELDUMPMAGIC) != 0) 83 return (0); 84 if (strcmp(dh->architecture, "powerpc") != 0) 85 return (0); 86 /* That should do it... */ 87 return (sizeof(*dh)); 88 } 89 90 /* 91 * Map the ELF headers into the process' address space. We do this in two 92 * steps: first the ELF header itself and using that information the whole 93 * set of headers. 94 */ 95 static int 96 powerpc_maphdrs(kvm_t *kd) 97 { 98 struct vmstate *vm; 99 size_t mapsz; 100 101 vm = kd->vmst; 102 103 vm->mapsz = PAGE_SIZE; 104 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0); 105 if (vm->map == MAP_FAILED) { 106 _kvm_err(kd, kd->program, "cannot map corefile"); 107 return (-1); 108 } 109 vm->dmphdrsz = 0; 110 vm->eh = vm->map; 111 if (!valid_elf_header(vm->eh)) { 112 /* 113 * Hmmm, no ELF header. Maybe we still have a dump header. 114 * This is normal when the core file wasn't created by 115 * savecore(8), but instead was dumped over TFTP. We can 116 * easily skip the dump header... 117 */ 118 vm->dmphdrsz = dump_header_size(vm->map); 119 if (vm->dmphdrsz == 0) 120 goto inval; 121 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz); 122 if (!valid_elf_header(vm->eh)) 123 goto inval; 124 } 125 mapsz = be16toh(vm->eh->e_phentsize) * be16toh(vm->eh->e_phnum) + 126 be32toh(vm->eh->e_phoff); 127 munmap(vm->map, vm->mapsz); 128 129 /* Map all headers. */ 130 vm->mapsz = vm->dmphdrsz + mapsz; 131 vm->map = mmap(NULL, vm->mapsz, PROT_READ, MAP_PRIVATE, kd->pmfd, 0); 132 if (vm->map == MAP_FAILED) { 133 _kvm_err(kd, kd->program, "cannot map corefle headers"); 134 return (-1); 135 } 136 vm->eh = (void *)((uintptr_t)vm->map + vm->dmphdrsz); 137 vm->ph = (void *)((uintptr_t)vm->eh + be32toh(vm->eh->e_phoff)); 138 return (0); 139 140 inval: 141 munmap(vm->map, vm->mapsz); 142 vm->map = MAP_FAILED; 143 _kvm_err(kd, kd->program, "invalid corefile"); 144 return (-1); 145 } 146 147 /* 148 * Determine the offset within the corefile corresponding the virtual 149 * address. Return the number of contiguous bytes in the corefile or 150 * 0 when the virtual address is invalid. 151 */ 152 static size_t 153 powerpc_va2off(kvm_t *kd, u_long va, off_t *ofs) 154 { 155 struct vmstate *vm = kd->vmst; 156 Elf32_Phdr *ph; 157 int nph; 158 159 ph = vm->ph; 160 nph = be16toh(vm->eh->e_phnum); 161 while (nph && (va < be32toh(ph->p_vaddr) || 162 va >= be32toh(ph->p_vaddr) + be32toh(ph->p_memsz))) { 163 nph--; 164 ph = (void *)((uintptr_t)ph + be16toh(vm->eh->e_phentsize)); 165 } 166 if (nph == 0) 167 return (0); 168 169 /* Segment found. Return file offset and range. */ 170 *ofs = vm->dmphdrsz + be32toh(ph->p_offset) + 171 (va - be32toh(ph->p_vaddr)); 172 return (be32toh(ph->p_memsz) - (va - be32toh(ph->p_vaddr))); 173 } 174 175 void 176 _kvm_freevtop(kvm_t *kd) 177 { 178 struct vmstate *vm = kd->vmst; 179 180 if (vm == NULL) 181 return; 182 183 if (vm->eh != MAP_FAILED) { 184 munmap(vm->eh, vm->mapsz); 185 vm->eh = MAP_FAILED; 186 } 187 free(vm); 188 kd->vmst = NULL; 189 } 190 191 int 192 _kvm_initvtop(kvm_t *kd) 193 { 194 195 kd->vmst = (struct vmstate *)_kvm_malloc(kd, sizeof(*kd->vmst)); 196 if (kd->vmst == NULL) { 197 _kvm_err(kd, kd->program, "out of virtual memory"); 198 return (-1); 199 } 200 if (powerpc_maphdrs(kd) == -1) { 201 free(kd->vmst); 202 kd->vmst = NULL; 203 return (-1); 204 } 205 return (0); 206 } 207 208 int 209 _kvm_kvatop(kvm_t *kd, u_long va, off_t *ofs) 210 { 211 struct vmstate *vm; 212 213 vm = kd->vmst; 214 if (vm->ph->p_paddr == ~0U) 215 return ((int)powerpc_va2off(kd, va, ofs)); 216 217 _kvm_err(kd, kd->program, "Raw corefile not supported"); 218 return (0); 219 } 220