1/* 2 * fs/proc/kcore.c kernel ELF/AOUT core dumper 3 * 4 * Modelled on fs/exec.c:aout_core_dump() 5 * Jeremy Fitzhardinge <jeremy@sw.oz.au> 6 * ELF version written by David Howells <David.Howells@nexor.co.uk> 7 * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com> 8 * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com> 9 * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com> 10 */ 11 12#include <linux/config.h> 13#include <linux/mm.h> 14#include <linux/proc_fs.h> 15#include <linux/user.h> 16#include <linux/a.out.h> 17#include <linux/elf.h> 18#include <linux/elfcore.h> 19#include <linux/vmalloc.h> 20#include <linux/highmem.h> 21#include <asm/uaccess.h> 22#include <asm/io.h> 23 24 25static int open_kcore(struct inode * inode, struct file * filp) 26{ 27 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; 28} 29 30static ssize_t read_kcore(struct file *, char *, size_t, loff_t *); 31 32struct file_operations proc_kcore_operations = { 33 read: read_kcore, 34 open: open_kcore, 35}; 36 37#ifdef CONFIG_KCORE_AOUT 38static ssize_t read_kcore(struct file *file, char *buf, size_t count, loff_t *ppos) 39{ 40 unsigned long long p = *ppos, memsize; 41 ssize_t read; 42 ssize_t count1; 43 char * pnt; 44 struct user dump; 45#if defined(__i386__) || defined(__mc68000__) || defined(__x86_64__) 46# define FIRST_MAPPED PAGE_SIZE /* we don't have page 0 mapped on x86.. */ 47#else 48# define FIRST_MAPPED 0 49#endif 50 51 memset(&dump, 0, sizeof(struct user)); 52 dump.magic = CMAGIC; 53 dump.u_dsize = (virt_to_phys(high_memory) >> PAGE_SHIFT); 54#if defined(__i386__) || defined(__x86_64__) 55 dump.start_code = PAGE_OFFSET; 56#endif 57#ifdef __alpha__ 58 dump.start_data = PAGE_OFFSET; 59#endif 60 61 memsize = virt_to_phys(high_memory); 62 if (p >= memsize) 63 return 0; 64 if (count > memsize - p) 65 count = memsize - p; 66 read = 0; 67 68 if (p < sizeof(struct user) && count > 0) { 69 count1 = count; 70 if (p + count1 > sizeof(struct user)) 71 count1 = sizeof(struct user)-p; 72 pnt = (char *) &dump + p; 73 if (copy_to_user(buf,(void *) pnt, count1)) 74 return -EFAULT; 75 buf += count1; 76 p += count1; 77 count -= count1; 78 read += count1; 79 } 80 81 if (count > 0 && p < PAGE_SIZE + FIRST_MAPPED) { 82 count1 = PAGE_SIZE + FIRST_MAPPED - p; 83 if (count1 > count) 84 count1 = count; 85 if (clear_user(buf, count1)) 86 return -EFAULT; 87 buf += count1; 88 p += count1; 89 count -= count1; 90 read += count1; 91 } 92 if (count > 0) { 93 if (copy_to_user(buf, (void *) (PAGE_OFFSET+p-PAGE_SIZE), count)) 94 return -EFAULT; 95 read += count; 96 } 97 *ppos += read; 98 return read; 99} 100#else /* CONFIG_KCORE_AOUT */ 101 102#define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) 103 104/* An ELF note in memory */ 105struct memelfnote 106{ 107 const char *name; 108 int type; 109 unsigned int datasz; 110 void *data; 111}; 112 113extern char saved_command_line[]; 114 115static size_t get_kcore_size(int *num_vma, size_t *elf_buflen) 116{ 117 size_t try, size; 118 struct vm_struct *m; 119 120 *num_vma = 0; 121 size = ((size_t)high_memory - PAGE_OFFSET + PAGE_SIZE); 122 if (!vmlist) { 123 *elf_buflen = PAGE_SIZE; 124 return (size); 125 } 126 127 for (m=vmlist; m; m=m->next) { 128 try = (size_t)m->addr + m->size; 129 if (try > size) 130 size = try; 131 *num_vma = *num_vma + 1; 132 } 133 *elf_buflen = sizeof(struct elfhdr) + 134 (*num_vma + 2)*sizeof(struct elf_phdr) + 135 3 * sizeof(struct memelfnote); 136 *elf_buflen = PAGE_ALIGN(*elf_buflen); 137 return (size - PAGE_OFFSET + *elf_buflen); 138} 139 140 141/*****************************************************************************/ 142/* 143 * determine size of ELF note 144 */ 145static int notesize(struct memelfnote *en) 146{ 147 int sz; 148 149 sz = sizeof(struct elf_note); 150 sz += roundup(strlen(en->name), 4); 151 sz += roundup(en->datasz, 4); 152 153 return sz; 154} /* end notesize() */ 155 156/*****************************************************************************/ 157/* 158 * store a note in the header buffer 159 */ 160static char *storenote(struct memelfnote *men, char *bufp) 161{ 162 struct elf_note en; 163 164#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0) 165 166 en.n_namesz = strlen(men->name); 167 en.n_descsz = men->datasz; 168 en.n_type = men->type; 169 170 DUMP_WRITE(&en, sizeof(en)); 171 DUMP_WRITE(men->name, en.n_namesz); 172 173 bufp = (char*) roundup((unsigned long)bufp,4); 174 DUMP_WRITE(men->data, men->datasz); 175 bufp = (char*) roundup((unsigned long)bufp,4); 176 177#undef DUMP_WRITE 178 179 return bufp; 180} /* end storenote() */ 181 182/* 183 * store an ELF coredump header in the supplied buffer 184 * num_vma is the number of elements in vmlist 185 */ 186static void elf_kcore_store_hdr(char *bufp, int num_vma, int dataoff) 187{ 188 struct elf_prstatus prstatus; /* NT_PRSTATUS */ 189 struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */ 190 struct elf_phdr *nhdr, *phdr; 191 struct elfhdr *elf; 192 struct memelfnote notes[3]; 193 off_t offset = 0; 194 struct vm_struct *m; 195 196 /* setup ELF header */ 197 elf = (struct elfhdr *) bufp; 198 bufp += sizeof(struct elfhdr); 199 offset += sizeof(struct elfhdr); 200 memcpy(elf->e_ident, ELFMAG, SELFMAG); 201 elf->e_ident[EI_CLASS] = ELF_CLASS; 202 elf->e_ident[EI_DATA] = ELF_DATA; 203 elf->e_ident[EI_VERSION]= EV_CURRENT; 204 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); 205 elf->e_type = ET_CORE; 206 elf->e_machine = ELF_ARCH; 207 elf->e_version = EV_CURRENT; 208 elf->e_entry = 0; 209 elf->e_phoff = sizeof(struct elfhdr); 210 elf->e_shoff = 0; 211 elf->e_flags = 0; 212 elf->e_ehsize = sizeof(struct elfhdr); 213 elf->e_phentsize= sizeof(struct elf_phdr); 214 elf->e_phnum = 2 + num_vma; 215 elf->e_shentsize= 0; 216 elf->e_shnum = 0; 217 elf->e_shstrndx = 0; 218 219 /* setup ELF PT_NOTE program header */ 220 nhdr = (struct elf_phdr *) bufp; 221 bufp += sizeof(struct elf_phdr); 222 offset += sizeof(struct elf_phdr); 223 nhdr->p_type = PT_NOTE; 224 nhdr->p_offset = 0; 225 nhdr->p_vaddr = 0; 226 nhdr->p_paddr = 0; 227 nhdr->p_filesz = 0; 228 nhdr->p_memsz = 0; 229 nhdr->p_flags = 0; 230 nhdr->p_align = 0; 231 232 /* setup ELF PT_LOAD program header for the 233 * virtual range 0xc0000000 -> high_memory */ 234 phdr = (struct elf_phdr *) bufp; 235 bufp += sizeof(struct elf_phdr); 236 offset += sizeof(struct elf_phdr); 237 phdr->p_type = PT_LOAD; 238 phdr->p_flags = PF_R|PF_W|PF_X; 239 phdr->p_offset = dataoff; 240 phdr->p_vaddr = PAGE_OFFSET; 241 phdr->p_paddr = __pa(PAGE_OFFSET); 242 phdr->p_filesz = phdr->p_memsz = ((unsigned long)high_memory - PAGE_OFFSET); 243 phdr->p_align = PAGE_SIZE; 244 245 /* setup ELF PT_LOAD program header for every vmalloc'd area */ 246 for (m=vmlist; m; m=m->next) { 247 if (m->flags & VM_IOREMAP) /* don't dump ioremap'd stuff! (TA) */ 248 continue; 249 250 phdr = (struct elf_phdr *) bufp; 251 bufp += sizeof(struct elf_phdr); 252 offset += sizeof(struct elf_phdr); 253 254 phdr->p_type = PT_LOAD; 255 phdr->p_flags = PF_R|PF_W|PF_X; 256 phdr->p_offset = (size_t)m->addr - PAGE_OFFSET + dataoff; 257 phdr->p_vaddr = (size_t)m->addr; 258 phdr->p_paddr = __pa(m->addr); 259 phdr->p_filesz = phdr->p_memsz = m->size; 260 phdr->p_align = PAGE_SIZE; 261 } 262 263 /* 264 * Set up the notes in similar form to SVR4 core dumps made 265 * with info from their /proc. 266 */ 267 nhdr->p_offset = offset; 268 269 /* set up the process status */ 270 notes[0].name = "CORE"; 271 notes[0].type = NT_PRSTATUS; 272 notes[0].datasz = sizeof(struct elf_prstatus); 273 notes[0].data = &prstatus; 274 275 memset(&prstatus, 0, sizeof(struct elf_prstatus)); 276 277 nhdr->p_filesz = notesize(¬es[0]); 278 bufp = storenote(¬es[0], bufp); 279 280 /* set up the process info */ 281 notes[1].name = "CORE"; 282 notes[1].type = NT_PRPSINFO; 283 notes[1].datasz = sizeof(struct elf_prpsinfo); 284 notes[1].data = &prpsinfo; 285 286 memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo)); 287 prpsinfo.pr_state = 0; 288 prpsinfo.pr_sname = 'R'; 289 prpsinfo.pr_zomb = 0; 290 291 strcpy(prpsinfo.pr_fname, "vmlinux"); 292 strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ); 293 294 nhdr->p_filesz = notesize(¬es[1]); 295 bufp = storenote(¬es[1], bufp); 296 297 /* set up the task structure */ 298 notes[2].name = "CORE"; 299 notes[2].type = NT_TASKSTRUCT; 300 notes[2].datasz = sizeof(struct task_struct); 301 notes[2].data = current; 302 303 nhdr->p_filesz = notesize(¬es[2]); 304 bufp = storenote(¬es[2], bufp); 305 306} /* end elf_kcore_store_hdr() */ 307 308/*****************************************************************************/ 309/* 310 * read from the ELF header and then kernel memory 311 */ 312static ssize_t read_kcore(struct file *file, char *buffer, size_t buflen, loff_t *fpos) 313{ 314 ssize_t acc = 0; 315 size_t size, tsz; 316 size_t elf_buflen; 317 int num_vma; 318 unsigned long start; 319 320 read_lock(&vmlist_lock); 321 proc_root_kcore->size = size = get_kcore_size(&num_vma, &elf_buflen); 322 if (buflen == 0 || *fpos >= size) { 323 read_unlock(&vmlist_lock); 324 return 0; 325 } 326 327 /* trim buflen to not go beyond EOF */ 328 if (buflen > size - *fpos) 329 buflen = size - *fpos; 330 331 /* construct an ELF core header if we'll need some of it */ 332 if (*fpos < elf_buflen) { 333 char * elf_buf; 334 335 tsz = elf_buflen - *fpos; 336 if (buflen < tsz) 337 tsz = buflen; 338 elf_buf = kmalloc(elf_buflen, GFP_ATOMIC); 339 if (!elf_buf) { 340 read_unlock(&vmlist_lock); 341 return -ENOMEM; 342 } 343 memset(elf_buf, 0, elf_buflen); 344 elf_kcore_store_hdr(elf_buf, num_vma, elf_buflen); 345 read_unlock(&vmlist_lock); 346 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) { 347 kfree(elf_buf); 348 return -EFAULT; 349 } 350 kfree(elf_buf); 351 buflen -= tsz; 352 *fpos += tsz; 353 buffer += tsz; 354 acc += tsz; 355 356 /* leave now if filled buffer already */ 357 if (buflen == 0) 358 return acc; 359 } else 360 read_unlock(&vmlist_lock); 361 362 /* where page 0 not mapped, write zeros into buffer */ 363#if defined(__i386__) || defined(__mc68000__) || defined(__x86_64__) 364 if (*fpos < PAGE_SIZE + elf_buflen) { 365 /* work out how much to clear */ 366 tsz = PAGE_SIZE + elf_buflen - *fpos; 367 if (buflen < tsz) 368 tsz = buflen; 369 370 /* write zeros to buffer */ 371 if (clear_user(buffer, tsz)) 372 return -EFAULT; 373 buflen -= tsz; 374 *fpos += tsz; 375 buffer += tsz; 376 acc += tsz; 377 378 /* leave now if filled buffer already */ 379 if (buflen == 0) 380 return tsz; 381 } 382#endif 383 384 /* 385 * Fill the remainder of the buffer from kernel VM space. 386 * We said in the ELF header that the data which starts 387 * at 'elf_buflen' is virtual address PAGE_OFFSET. --rmk 388 */ 389 start = PAGE_OFFSET + (*fpos - elf_buflen); 390 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) 391 tsz = buflen; 392 393 while (buflen) { 394 if ((start >= VMALLOC_START) && (start < VMALLOC_END)) { 395 char * elf_buf; 396 struct vm_struct *m; 397 unsigned long curstart = start; 398 unsigned long cursize = tsz; 399 400 elf_buf = kmalloc(tsz, GFP_KERNEL); 401 if (!elf_buf) 402 return -ENOMEM; 403 memset(elf_buf, 0, tsz); 404 405 read_lock(&vmlist_lock); 406 for (m=vmlist; m && cursize; m=m->next) { 407 unsigned long vmstart; 408 unsigned long vmsize; 409 unsigned long msize = m->size - PAGE_SIZE; 410 411 if (((unsigned long)m->addr + msize) < 412 curstart) 413 continue; 414 if ((unsigned long)m->addr > (curstart + 415 cursize)) 416 break; 417 vmstart = (curstart < (unsigned long)m->addr ? 418 (unsigned long)m->addr : curstart); 419 if (((unsigned long)m->addr + msize) > 420 (curstart + cursize)) 421 vmsize = curstart + cursize - vmstart; 422 else 423 vmsize = (unsigned long)m->addr + 424 msize - vmstart; 425 curstart = vmstart + vmsize; 426 cursize -= vmsize; 427 /* don't dump ioremap'd stuff! (TA) */ 428 if (m->flags & VM_IOREMAP) 429 continue; 430 memcpy(elf_buf + (vmstart - start), 431 (char *)vmstart, vmsize); 432 } 433 read_unlock(&vmlist_lock); 434 if (copy_to_user(buffer, elf_buf, tsz)) { 435 kfree(elf_buf); 436 return -EFAULT; 437 } 438 kfree(elf_buf); 439 } else if ((start > PAGE_OFFSET) && (start < 440 (unsigned long)high_memory)) { 441 if (kern_addr_valid(start)) { 442 if (copy_to_user(buffer, (char *)start, tsz)) 443 return -EFAULT; 444 } else { 445 if (clear_user(buffer, tsz)) 446 return -EFAULT; 447 } 448 } else { 449 if (clear_user(buffer, tsz)) 450 return -EFAULT; 451 } 452 buflen -= tsz; 453 *fpos += tsz; 454 buffer += tsz; 455 acc += tsz; 456 start += tsz; 457 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); 458 } 459 460 return acc; 461} 462#endif /* CONFIG_KCORE_AOUT */ 463