imgact_elf.c revision 65770
1/*- 2 * Copyright (c) 1995-1996 S�ren Schmidt 3 * Copyright (c) 1996 Peter Wemm 4 * 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 * in this position and unchanged. 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 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software withough specific prior written permission 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * $FreeBSD: head/sys/kern/imgact_elf.c 65770 2000-09-12 09:49:08Z bp $ 30 */ 31 32#include "opt_rlimit.h" 33 34#include <sys/param.h> 35#include <sys/exec.h> 36#include <sys/fcntl.h> 37#include <sys/imgact.h> 38#include <sys/imgact_elf.h> 39#include <sys/kernel.h> 40#include <sys/malloc.h> 41#include <sys/mman.h> 42#include <sys/namei.h> 43#include <sys/pioctl.h> 44#include <sys/proc.h> 45#include <sys/procfs.h> 46#include <sys/resourcevar.h> 47#include <sys/systm.h> 48#include <sys/signalvar.h> 49#include <sys/stat.h> 50#include <sys/syscall.h> 51#include <sys/sysctl.h> 52#include <sys/sysent.h> 53#include <sys/vnode.h> 54 55#include <vm/vm.h> 56#include <vm/vm_kern.h> 57#include <vm/vm_param.h> 58#include <vm/pmap.h> 59#include <sys/lock.h> 60#include <vm/vm_map.h> 61#include <vm/vm_object.h> 62#include <vm/vm_extern.h> 63 64#include <machine/elf.h> 65#include <machine/md_var.h> 66 67#define OLD_EI_BRAND 8 68 69__ElfType(Brandinfo); 70__ElfType(Auxargs); 71 72static int elf_check_header __P((const Elf_Ehdr *hdr)); 73static int elf_freebsd_fixup __P((register_t **stack_base, 74 struct image_params *imgp)); 75static int elf_load_file __P((struct proc *p, const char *file, u_long *addr, 76 u_long *entry)); 77static int elf_load_section __P((struct proc *p, 78 struct vmspace *vmspace, struct vnode *vp, 79 vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, 80 vm_prot_t prot)); 81static int exec_elf_imgact __P((struct image_params *imgp)); 82 83static int elf_trace = 0; 84SYSCTL_INT(_debug, OID_AUTO, elf_trace, CTLFLAG_RW, &elf_trace, 0, ""); 85 86static struct sysentvec elf_freebsd_sysvec = { 87 SYS_MAXSYSCALL, 88 sysent, 89 0, 90 0, 91 0, 92 0, 93 0, 94 0, 95 elf_freebsd_fixup, 96 sendsig, 97 sigcode, 98 &szsigcode, 99 0, 100 "FreeBSD ELF", 101 elf_coredump 102}; 103 104static Elf_Brandinfo freebsd_brand_info = { 105 ELFOSABI_FREEBSD, 106 "", 107 "/usr/libexec/ld-elf.so.1", 108 &elf_freebsd_sysvec 109 }; 110static Elf_Brandinfo *elf_brand_list[MAX_BRANDS] = { 111 &freebsd_brand_info, 112 NULL, NULL, NULL, 113 NULL, NULL, NULL, NULL 114 }; 115 116int 117elf_insert_brand_entry(Elf_Brandinfo *entry) 118{ 119 int i; 120 121 for (i=1; i<MAX_BRANDS; i++) { 122 if (elf_brand_list[i] == NULL) { 123 elf_brand_list[i] = entry; 124 break; 125 } 126 } 127 if (i == MAX_BRANDS) 128 return -1; 129 return 0; 130} 131 132int 133elf_remove_brand_entry(Elf_Brandinfo *entry) 134{ 135 int i; 136 137 for (i=1; i<MAX_BRANDS; i++) { 138 if (elf_brand_list[i] == entry) { 139 elf_brand_list[i] = NULL; 140 break; 141 } 142 } 143 if (i == MAX_BRANDS) 144 return -1; 145 return 0; 146} 147 148int 149elf_brand_inuse(Elf_Brandinfo *entry) 150{ 151 struct proc *p; 152 153 LIST_FOREACH(p, &allproc, p_list) { 154 if (p->p_sysent == entry->sysvec) 155 return TRUE; 156 } 157 158 return FALSE; 159} 160 161static int 162elf_check_header(const Elf_Ehdr *hdr) 163{ 164 if (!IS_ELF(*hdr) || 165 hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 166 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 167 hdr->e_ident[EI_VERSION] != EV_CURRENT) 168 return ENOEXEC; 169 170 if (!ELF_MACHINE_OK(hdr->e_machine)) 171 return ENOEXEC; 172 173 if (hdr->e_version != ELF_TARG_VER) 174 return ENOEXEC; 175 176 return 0; 177} 178 179static int 180elf_load_section(struct proc *p, struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot) 181{ 182 size_t map_len; 183 vm_offset_t map_addr; 184 int error, rv; 185 size_t copy_len; 186 vm_object_t object; 187 vm_offset_t file_addr; 188 vm_offset_t data_buf = 0; 189 190 VOP_GETVOBJECT(vp, &object); 191 error = 0; 192 193 /* 194 * It's necessary to fail if the filsz + offset taken from the 195 * header is greater than the actual file pager object's size. 196 * If we were to allow this, then the vm_map_find() below would 197 * walk right off the end of the file object and into the ether. 198 * 199 * While I'm here, might as well check for something else that 200 * is invalid: filsz cannot be greater than memsz. 201 */ 202 if ((off_t)filsz + offset > object->un_pager.vnp.vnp_size || 203 filsz > memsz) { 204 uprintf("elf_load_section: truncated ELF file\n"); 205 return (ENOEXEC); 206 } 207 208 map_addr = trunc_page((vm_offset_t)vmaddr); 209 file_addr = trunc_page(offset); 210 211 /* 212 * We have two choices. We can either clear the data in the last page 213 * of an oversized mapping, or we can start the anon mapping a page 214 * early and copy the initialized data into that first page. We 215 * choose the second.. 216 */ 217 if (memsz > filsz) 218 map_len = trunc_page(offset+filsz) - file_addr; 219 else 220 map_len = round_page(offset+filsz) - file_addr; 221 222 if (map_len != 0) { 223 vm_object_reference(object); 224 vm_map_lock(&vmspace->vm_map); 225 rv = vm_map_insert(&vmspace->vm_map, 226 object, 227 file_addr, /* file offset */ 228 map_addr, /* virtual start */ 229 map_addr + map_len,/* virtual end */ 230 prot, 231 VM_PROT_ALL, 232 MAP_COPY_ON_WRITE | MAP_PREFAULT); 233 vm_map_unlock(&vmspace->vm_map); 234 if (rv != KERN_SUCCESS) { 235 vm_object_deallocate(object); 236 return EINVAL; 237 } 238 239 /* we can stop now if we've covered it all */ 240 if (memsz == filsz) 241 return 0; 242 } 243 244 245 /* 246 * We have to get the remaining bit of the file into the first part 247 * of the oversized map segment. This is normally because the .data 248 * segment in the file is extended to provide bss. It's a neat idea 249 * to try and save a page, but it's a pain in the behind to implement. 250 */ 251 copy_len = (offset + filsz) - trunc_page(offset + filsz); 252 map_addr = trunc_page((vm_offset_t)vmaddr + filsz); 253 map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr; 254 255 /* This had damn well better be true! */ 256 if (map_len != 0) { 257 vm_map_lock(&vmspace->vm_map); 258 rv = vm_map_insert(&vmspace->vm_map, NULL, 0, 259 map_addr, map_addr + map_len, 260 VM_PROT_ALL, VM_PROT_ALL, 0); 261 vm_map_unlock(&vmspace->vm_map); 262 if (rv != KERN_SUCCESS) 263 return EINVAL; 264 } 265 266 if (copy_len != 0) { 267 vm_object_reference(object); 268 rv = vm_map_find(exec_map, 269 object, 270 trunc_page(offset + filsz), 271 &data_buf, 272 PAGE_SIZE, 273 TRUE, 274 VM_PROT_READ, 275 VM_PROT_ALL, 276 MAP_COPY_ON_WRITE | MAP_PREFAULT_PARTIAL); 277 if (rv != KERN_SUCCESS) { 278 vm_object_deallocate(object); 279 return EINVAL; 280 } 281 282 /* send the page fragment to user space */ 283 error = copyout((caddr_t)data_buf, (caddr_t)map_addr, copy_len); 284 vm_map_remove(exec_map, data_buf, data_buf + PAGE_SIZE); 285 if (error) 286 return (error); 287 } 288 289 /* 290 * set it to the specified protection 291 */ 292 vm_map_protect(&vmspace->vm_map, map_addr, map_addr + map_len, prot, 293 FALSE); 294 295 return error; 296} 297 298/* 299 * Load the file "file" into memory. It may be either a shared object 300 * or an executable. 301 * 302 * The "addr" reference parameter is in/out. On entry, it specifies 303 * the address where a shared object should be loaded. If the file is 304 * an executable, this value is ignored. On exit, "addr" specifies 305 * where the file was actually loaded. 306 * 307 * The "entry" reference parameter is out only. On exit, it specifies 308 * the entry point for the loaded file. 309 */ 310static int 311elf_load_file(struct proc *p, const char *file, u_long *addr, u_long *entry) 312{ 313 const Elf_Ehdr *hdr = NULL; 314 const Elf_Phdr *phdr = NULL; 315 struct nameidata nd; 316 struct vmspace *vmspace = p->p_vmspace; 317 struct vattr attr; 318 struct image_params image_params, *imgp; 319 vm_prot_t prot; 320 u_long rbase; 321 u_long base_addr = 0; 322 int error, i, numsegs; 323 324 imgp = &image_params; 325 /* 326 * Initialize part of the common data 327 */ 328 imgp->proc = p; 329 imgp->uap = NULL; 330 imgp->attr = &attr; 331 imgp->firstpage = NULL; 332 imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE); 333 334 if (imgp->image_header == NULL) { 335 nd.ni_vp = NULL; 336 error = ENOMEM; 337 goto fail; 338 } 339 340 NDINIT(&nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, p); 341 342 if ((error = namei(&nd)) != 0) { 343 nd.ni_vp = NULL; 344 goto fail; 345 } 346 NDFREE(&nd, NDF_ONLY_PNBUF); 347 imgp->vp = nd.ni_vp; 348 349 /* 350 * Check permissions, modes, uid, etc on the file, and "open" it. 351 */ 352 error = exec_check_permissions(imgp); 353 if (error) { 354 VOP_UNLOCK(nd.ni_vp, 0, p); 355 goto fail; 356 } 357 358 error = exec_map_first_page(imgp); 359 /* 360 * Also make certain that the interpreter stays the same, so set 361 * its VTEXT flag, too. 362 */ 363 if (error == 0) 364 nd.ni_vp->v_flag |= VTEXT; 365 VOP_UNLOCK(nd.ni_vp, 0, p); 366 if (error) 367 goto fail; 368 369 hdr = (const Elf_Ehdr *)imgp->image_header; 370 if ((error = elf_check_header(hdr)) != 0) 371 goto fail; 372 if (hdr->e_type == ET_DYN) 373 rbase = *addr; 374 else if (hdr->e_type == ET_EXEC) 375 rbase = 0; 376 else { 377 error = ENOEXEC; 378 goto fail; 379 } 380 381 /* Only support headers that fit within first page for now */ 382 if ((hdr->e_phoff > PAGE_SIZE) || 383 (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) { 384 error = ENOEXEC; 385 goto fail; 386 } 387 388 phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff); 389 390 for (i = 0, numsegs = 0; i < hdr->e_phnum; i++) { 391 if (phdr[i].p_type == PT_LOAD) { /* Loadable segment */ 392 prot = 0; 393 if (phdr[i].p_flags & PF_X) 394 prot |= VM_PROT_EXECUTE; 395 if (phdr[i].p_flags & PF_W) 396 prot |= VM_PROT_WRITE; 397 if (phdr[i].p_flags & PF_R) 398 prot |= VM_PROT_READ; 399 400 if ((error = elf_load_section(p, vmspace, nd.ni_vp, 401 phdr[i].p_offset, 402 (caddr_t)phdr[i].p_vaddr + 403 rbase, 404 phdr[i].p_memsz, 405 phdr[i].p_filesz, prot)) != 0) 406 goto fail; 407 /* 408 * Establish the base address if this is the 409 * first segment. 410 */ 411 if (numsegs == 0) 412 base_addr = trunc_page(phdr[i].p_vaddr + rbase); 413 numsegs++; 414 } 415 } 416 *addr = base_addr; 417 *entry=(unsigned long)hdr->e_entry + rbase; 418 419fail: 420 if (imgp->firstpage) 421 exec_unmap_first_page(imgp); 422 if (imgp->image_header) 423 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header, 424 PAGE_SIZE); 425 if (nd.ni_vp) 426 vrele(nd.ni_vp); 427 428 return error; 429} 430 431static int fallback_elf_brand = ELFOSABI_FREEBSD; 432SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW, 433 &fallback_elf_brand, ELFOSABI_FREEBSD, 434 "ELF brand of last resort"); 435 436static int 437exec_elf_imgact(struct image_params *imgp) 438{ 439 const Elf_Ehdr *hdr = (const Elf_Ehdr *) imgp->image_header; 440 const Elf_Phdr *phdr; 441 Elf_Auxargs *elf_auxargs = NULL; 442 struct vmspace *vmspace; 443 vm_prot_t prot; 444 u_long text_size = 0, data_size = 0; 445 u_long text_addr = 0, data_addr = 0; 446 u_long addr, entry = 0, proghdr = 0; 447 int error, i; 448 const char *interp = NULL; 449 Elf_Brandinfo *brand_info; 450 char path[MAXPATHLEN]; 451 452 /* 453 * Do we have a valid ELF header ? 454 */ 455 if (elf_check_header(hdr) != 0 || hdr->e_type != ET_EXEC) 456 return -1; 457 458 /* 459 * From here on down, we return an errno, not -1, as we've 460 * detected an ELF file. 461 */ 462 463 if ((hdr->e_phoff > PAGE_SIZE) || 464 (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) { 465 /* Only support headers in first page for now */ 466 return ENOEXEC; 467 } 468 phdr = (const Elf_Phdr*)(imgp->image_header + hdr->e_phoff); 469 470 /* 471 * From this point on, we may have resources that need to be freed. 472 */ 473 474 /* 475 * Yeah, I'm paranoid. There is every reason in the world to get 476 * VTEXT now since from here on out, there are places we can have 477 * a context switch. Better safe than sorry; I really don't want 478 * the file to change while it's being loaded. 479 */ 480 simple_lock(&imgp->vp->v_interlock); 481 imgp->vp->v_flag |= VTEXT; 482 simple_unlock(&imgp->vp->v_interlock); 483 484 if ((error = exec_extract_strings(imgp)) != 0) 485 goto fail; 486 487 exec_new_vmspace(imgp); 488 489 vmspace = imgp->proc->p_vmspace; 490 491 for (i = 0; i < hdr->e_phnum; i++) { 492 switch(phdr[i].p_type) { 493 494 case PT_LOAD: /* Loadable segment */ 495 prot = 0; 496 if (phdr[i].p_flags & PF_X) 497 prot |= VM_PROT_EXECUTE; 498 if (phdr[i].p_flags & PF_W) 499 prot |= VM_PROT_WRITE; 500 if (phdr[i].p_flags & PF_R) 501 prot |= VM_PROT_READ; 502 503 if ((error = elf_load_section(imgp->proc, 504 vmspace, imgp->vp, 505 phdr[i].p_offset, 506 (caddr_t)phdr[i].p_vaddr, 507 phdr[i].p_memsz, 508 phdr[i].p_filesz, prot)) != 0) 509 goto fail; 510 511 /* 512 * Is this .text or .data ?? 513 * 514 * We only handle one each of those yet XXX 515 */ 516 if (hdr->e_entry >= phdr[i].p_vaddr && 517 hdr->e_entry <(phdr[i].p_vaddr+phdr[i].p_memsz)) { 518 text_addr = trunc_page(phdr[i].p_vaddr); 519 text_size = round_page(phdr[i].p_memsz + 520 phdr[i].p_vaddr - 521 text_addr); 522 entry = (u_long)hdr->e_entry; 523 } else { 524 data_addr = trunc_page(phdr[i].p_vaddr); 525 data_size = round_page(phdr[i].p_memsz + 526 phdr[i].p_vaddr - 527 data_addr); 528 } 529 break; 530 case PT_INTERP: /* Path to interpreter */ 531 if (phdr[i].p_filesz > MAXPATHLEN || 532 phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) { 533 error = ENOEXEC; 534 goto fail; 535 } 536 interp = imgp->image_header + phdr[i].p_offset; 537 break; 538 case PT_PHDR: /* Program header table info */ 539 proghdr = phdr[i].p_vaddr; 540 break; 541 default: 542 break; 543 } 544 } 545 546 vmspace->vm_tsize = text_size >> PAGE_SHIFT; 547 vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr; 548 vmspace->vm_dsize = data_size >> PAGE_SHIFT; 549 vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr; 550 551 addr = ELF_RTLD_ADDR(vmspace); 552 553 imgp->entry_addr = entry; 554 555 brand_info = NULL; 556 557 /* XXX For now we look for the magic "FreeBSD" that we used to put 558 * into the ELF header at the EI_ABIVERSION location. If found use 559 * that information rather than figuring out the ABI from proper 560 * branding. This should be removed for 5.0-RELEASE. The Linux caes 561 * can be figured out from the `interp_path' field. 562 */ 563 if (strcmp("FreeBSD", (const char *)&hdr->e_ident[OLD_EI_BRAND]) == 0) 564 brand_info = &freebsd_brand_info; 565 566 /* If the executable has a brand, search for it in the brand list. */ 567 if (brand_info == NULL) { 568 for (i = 0; i < MAX_BRANDS; i++) { 569 Elf_Brandinfo *bi = elf_brand_list[i]; 570 571 if (bi != NULL && hdr->e_ident[EI_OSABI] == bi->brand) { 572 brand_info = bi; 573 break; 574 } 575 } 576 } 577 578 /* Lacking a known brand, search for a recognized interpreter. */ 579 if (brand_info == NULL && interp != NULL) { 580 for (i = 0; i < MAX_BRANDS; i++) { 581 Elf_Brandinfo *bi = elf_brand_list[i]; 582 583 if (bi != NULL && 584 strcmp(interp, bi->interp_path) == 0) { 585 brand_info = bi; 586 break; 587 } 588 } 589 } 590 591 /* Lacking a recognized interpreter, try the default brand */ 592 if (brand_info == NULL) { 593 for (i = 0; i < MAX_BRANDS; i++) { 594 Elf_Brandinfo *bi = elf_brand_list[i]; 595 596 if (bi != NULL && fallback_elf_brand == bi->brand) { 597 brand_info = bi; 598 break; 599 } 600 } 601 } 602 603 /* XXX - Assume FreeBSD after the branding method change. */ 604 if (brand_info == NULL) 605 brand_info = &freebsd_brand_info; 606 607 if (brand_info == NULL) { 608 uprintf("ELF binary type \"%u\" not known.\n", 609 hdr->e_ident[EI_OSABI]); 610 error = ENOEXEC; 611 goto fail; 612 } 613 614 imgp->proc->p_sysent = brand_info->sysvec; 615 if (interp != NULL) { 616 snprintf(path, sizeof(path), "%s%s", 617 brand_info->emul_path, interp); 618 if ((error = elf_load_file(imgp->proc, path, &addr, 619 &imgp->entry_addr)) != 0) { 620 if ((error = elf_load_file(imgp->proc, interp, &addr, 621 &imgp->entry_addr)) != 0) { 622 uprintf("ELF interpreter %s not found\n", path); 623 goto fail; 624 } 625 } 626 } 627 628 /* 629 * Construct auxargs table (used by the fixup routine) 630 */ 631 elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK); 632 elf_auxargs->execfd = -1; 633 elf_auxargs->phdr = proghdr; 634 elf_auxargs->phent = hdr->e_phentsize; 635 elf_auxargs->phnum = hdr->e_phnum; 636 elf_auxargs->pagesz = PAGE_SIZE; 637 elf_auxargs->base = addr; 638 elf_auxargs->flags = 0; 639 elf_auxargs->entry = entry; 640 elf_auxargs->trace = elf_trace; 641 642 imgp->auxargs = elf_auxargs; 643 imgp->interpreted = 0; 644 645fail: 646 return error; 647} 648 649static int 650elf_freebsd_fixup(register_t **stack_base, struct image_params *imgp) 651{ 652 Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs; 653 register_t *pos; 654 655 pos = *stack_base + (imgp->argc + imgp->envc + 2); 656 657 if (args->trace) { 658 AUXARGS_ENTRY(pos, AT_DEBUG, 1); 659 } 660 if (args->execfd != -1) { 661 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 662 } 663 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 664 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 665 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 666 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 667 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 668 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 669 AUXARGS_ENTRY(pos, AT_BASE, args->base); 670 AUXARGS_ENTRY(pos, AT_NULL, 0); 671 672 free(imgp->auxargs, M_TEMP); 673 imgp->auxargs = NULL; 674 675 (*stack_base)--; 676 suword(*stack_base, (long) imgp->argc); 677 return 0; 678} 679 680/* 681 * Code for generating ELF core dumps. 682 */ 683 684typedef void (*segment_callback) __P((vm_map_entry_t, void *)); 685 686/* Closure for cb_put_phdr(). */ 687struct phdr_closure { 688 Elf_Phdr *phdr; /* Program header to fill in */ 689 Elf_Off offset; /* Offset of segment in core file */ 690}; 691 692/* Closure for cb_size_segment(). */ 693struct sseg_closure { 694 int count; /* Count of writable segments. */ 695 size_t size; /* Total size of all writable segments. */ 696}; 697 698static void cb_put_phdr __P((vm_map_entry_t, void *)); 699static void cb_size_segment __P((vm_map_entry_t, void *)); 700static void each_writable_segment __P((struct proc *, segment_callback, 701 void *)); 702static int elf_corehdr __P((struct proc *, struct vnode *, struct ucred *, 703 int, void *, size_t)); 704static void elf_puthdr __P((struct proc *, void *, size_t *, 705 const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int)); 706static void elf_putnote __P((void *, size_t *, const char *, int, 707 const void *, size_t)); 708 709extern int osreldate; 710 711int 712elf_coredump(p, vp, limit) 713 register struct proc *p; 714 register struct vnode *vp; 715 off_t limit; 716{ 717 register struct ucred *cred = p->p_ucred; 718 int error = 0; 719 struct sseg_closure seginfo; 720 void *hdr; 721 size_t hdrsize; 722 723 /* Size the program segments. */ 724 seginfo.count = 0; 725 seginfo.size = 0; 726 each_writable_segment(p, cb_size_segment, &seginfo); 727 728 /* 729 * Calculate the size of the core file header area by making 730 * a dry run of generating it. Nothing is written, but the 731 * size is calculated. 732 */ 733 hdrsize = 0; 734 elf_puthdr((struct proc *)NULL, (void *)NULL, &hdrsize, 735 (const prstatus_t *)NULL, (const prfpregset_t *)NULL, 736 (const prpsinfo_t *)NULL, seginfo.count); 737 738 if (hdrsize + seginfo.size >= limit) 739 return (EFAULT); 740 741 /* 742 * Allocate memory for building the header, fill it up, 743 * and write it out. 744 */ 745 hdr = malloc(hdrsize, M_TEMP, M_WAITOK); 746 if (hdr == NULL) { 747 return EINVAL; 748 } 749 error = elf_corehdr(p, vp, cred, seginfo.count, hdr, hdrsize); 750 751 /* Write the contents of all of the writable segments. */ 752 if (error == 0) { 753 Elf_Phdr *php; 754 off_t offset; 755 int i; 756 757 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1; 758 offset = hdrsize; 759 for (i = 0; i < seginfo.count; i++) { 760 error = vn_rdwr(UIO_WRITE, vp, (caddr_t)php->p_vaddr, 761 php->p_filesz, offset, UIO_USERSPACE, 762 IO_NODELOCKED|IO_UNIT, cred, (int *)NULL, p); 763 if (error != 0) 764 break; 765 offset += php->p_filesz; 766 php++; 767 } 768 } 769 free(hdr, M_TEMP); 770 771 return error; 772} 773 774/* 775 * A callback for each_writable_segment() to write out the segment's 776 * program header entry. 777 */ 778static void 779cb_put_phdr(entry, closure) 780 vm_map_entry_t entry; 781 void *closure; 782{ 783 struct phdr_closure *phc = (struct phdr_closure *)closure; 784 Elf_Phdr *phdr = phc->phdr; 785 786 phc->offset = round_page(phc->offset); 787 788 phdr->p_type = PT_LOAD; 789 phdr->p_offset = phc->offset; 790 phdr->p_vaddr = entry->start; 791 phdr->p_paddr = 0; 792 phdr->p_filesz = phdr->p_memsz = entry->end - entry->start; 793 phdr->p_align = PAGE_SIZE; 794 phdr->p_flags = 0; 795 if (entry->protection & VM_PROT_READ) 796 phdr->p_flags |= PF_R; 797 if (entry->protection & VM_PROT_WRITE) 798 phdr->p_flags |= PF_W; 799 if (entry->protection & VM_PROT_EXECUTE) 800 phdr->p_flags |= PF_X; 801 802 phc->offset += phdr->p_filesz; 803 phc->phdr++; 804} 805 806/* 807 * A callback for each_writable_segment() to gather information about 808 * the number of segments and their total size. 809 */ 810static void 811cb_size_segment(entry, closure) 812 vm_map_entry_t entry; 813 void *closure; 814{ 815 struct sseg_closure *ssc = (struct sseg_closure *)closure; 816 817 ssc->count++; 818 ssc->size += entry->end - entry->start; 819} 820 821/* 822 * For each writable segment in the process's memory map, call the given 823 * function with a pointer to the map entry and some arbitrary 824 * caller-supplied data. 825 */ 826static void 827each_writable_segment(p, func, closure) 828 struct proc *p; 829 segment_callback func; 830 void *closure; 831{ 832 vm_map_t map = &p->p_vmspace->vm_map; 833 vm_map_entry_t entry; 834 835 for (entry = map->header.next; entry != &map->header; 836 entry = entry->next) { 837 vm_object_t obj; 838 839 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) || 840 (entry->protection & (VM_PROT_READ|VM_PROT_WRITE)) != 841 (VM_PROT_READ|VM_PROT_WRITE)) 842 continue; 843 844 /* 845 ** Dont include memory segment in the coredump if 846 ** MAP_NOCORE is set in mmap(2) or MADV_NOCORE in 847 ** madvise(2). 848 */ 849 if (entry->eflags & MAP_ENTRY_NOCOREDUMP) 850 continue; 851 852 if ((obj = entry->object.vm_object) == NULL) 853 continue; 854 855 /* Find the deepest backing object. */ 856 while (obj->backing_object != NULL) 857 obj = obj->backing_object; 858 859 /* Ignore memory-mapped devices and such things. */ 860 if (obj->type != OBJT_DEFAULT && 861 obj->type != OBJT_SWAP && 862 obj->type != OBJT_VNODE) 863 continue; 864 865 (*func)(entry, closure); 866 } 867} 868 869/* 870 * Write the core file header to the file, including padding up to 871 * the page boundary. 872 */ 873static int 874elf_corehdr(p, vp, cred, numsegs, hdr, hdrsize) 875 struct proc *p; 876 struct vnode *vp; 877 struct ucred *cred; 878 int numsegs; 879 size_t hdrsize; 880 void *hdr; 881{ 882 size_t off; 883 prstatus_t status; 884 prfpregset_t fpregset; 885 prpsinfo_t psinfo; 886 887 /* Gather the information for the header. */ 888 bzero(&status, sizeof status); 889 status.pr_version = PRSTATUS_VERSION; 890 status.pr_statussz = sizeof(prstatus_t); 891 status.pr_gregsetsz = sizeof(gregset_t); 892 status.pr_fpregsetsz = sizeof(fpregset_t); 893 status.pr_osreldate = osreldate; 894 status.pr_cursig = p->p_sig; 895 status.pr_pid = p->p_pid; 896 fill_regs(p, &status.pr_reg); 897 898 fill_fpregs(p, &fpregset); 899 900 bzero(&psinfo, sizeof psinfo); 901 psinfo.pr_version = PRPSINFO_VERSION; 902 psinfo.pr_psinfosz = sizeof(prpsinfo_t); 903 strncpy(psinfo.pr_fname, p->p_comm, MAXCOMLEN); 904 /* XXX - We don't fill in the command line arguments properly yet. */ 905 strncpy(psinfo.pr_psargs, p->p_comm, PRARGSZ); 906 907 /* Fill in the header. */ 908 bzero(hdr, hdrsize); 909 off = 0; 910 elf_puthdr(p, hdr, &off, &status, &fpregset, &psinfo, numsegs); 911 912 /* Write it to the core file. */ 913 return vn_rdwr(UIO_WRITE, vp, hdr, hdrsize, (off_t)0, 914 UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, NULL, p); 915} 916 917static void 918elf_puthdr(struct proc *p, void *dst, size_t *off, const prstatus_t *status, 919 const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs) 920{ 921 size_t ehoff; 922 size_t phoff; 923 size_t noteoff; 924 size_t notesz; 925 926 ehoff = *off; 927 *off += sizeof(Elf_Ehdr); 928 929 phoff = *off; 930 *off += (numsegs + 1) * sizeof(Elf_Phdr); 931 932 noteoff = *off; 933 elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status, 934 sizeof *status); 935 elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset, 936 sizeof *fpregset); 937 elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo, 938 sizeof *psinfo); 939 notesz = *off - noteoff; 940 941 /* Align up to a page boundary for the program segments. */ 942 *off = round_page(*off); 943 944 if (dst != NULL) { 945 Elf_Ehdr *ehdr; 946 Elf_Phdr *phdr; 947 struct phdr_closure phc; 948 949 /* 950 * Fill in the ELF header. 951 */ 952 ehdr = (Elf_Ehdr *)((char *)dst + ehoff); 953 ehdr->e_ident[EI_MAG0] = ELFMAG0; 954 ehdr->e_ident[EI_MAG1] = ELFMAG1; 955 ehdr->e_ident[EI_MAG2] = ELFMAG2; 956 ehdr->e_ident[EI_MAG3] = ELFMAG3; 957 ehdr->e_ident[EI_CLASS] = ELF_CLASS; 958 ehdr->e_ident[EI_DATA] = ELF_DATA; 959 ehdr->e_ident[EI_VERSION] = EV_CURRENT; 960 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD; 961 ehdr->e_ident[EI_ABIVERSION] = 0; 962 ehdr->e_ident[EI_PAD] = 0; 963 ehdr->e_type = ET_CORE; 964 ehdr->e_machine = ELF_ARCH; 965 ehdr->e_version = EV_CURRENT; 966 ehdr->e_entry = 0; 967 ehdr->e_phoff = phoff; 968 ehdr->e_flags = 0; 969 ehdr->e_ehsize = sizeof(Elf_Ehdr); 970 ehdr->e_phentsize = sizeof(Elf_Phdr); 971 ehdr->e_phnum = numsegs + 1; 972 ehdr->e_shentsize = sizeof(Elf_Shdr); 973 ehdr->e_shnum = 0; 974 ehdr->e_shstrndx = SHN_UNDEF; 975 976 /* 977 * Fill in the program header entries. 978 */ 979 phdr = (Elf_Phdr *)((char *)dst + phoff); 980 981 /* The note segement. */ 982 phdr->p_type = PT_NOTE; 983 phdr->p_offset = noteoff; 984 phdr->p_vaddr = 0; 985 phdr->p_paddr = 0; 986 phdr->p_filesz = notesz; 987 phdr->p_memsz = 0; 988 phdr->p_flags = 0; 989 phdr->p_align = 0; 990 phdr++; 991 992 /* All the writable segments from the program. */ 993 phc.phdr = phdr; 994 phc.offset = *off; 995 each_writable_segment(p, cb_put_phdr, &phc); 996 } 997} 998 999static void 1000elf_putnote(void *dst, size_t *off, const char *name, int type, 1001 const void *desc, size_t descsz) 1002{ 1003 Elf_Note note; 1004 1005 note.n_namesz = strlen(name) + 1; 1006 note.n_descsz = descsz; 1007 note.n_type = type; 1008 if (dst != NULL) 1009 bcopy(¬e, (char *)dst + *off, sizeof note); 1010 *off += sizeof note; 1011 if (dst != NULL) 1012 bcopy(name, (char *)dst + *off, note.n_namesz); 1013 *off += roundup2(note.n_namesz, sizeof(Elf_Size)); 1014 if (dst != NULL) 1015 bcopy(desc, (char *)dst + *off, note.n_descsz); 1016 *off += roundup2(note.n_descsz, sizeof(Elf_Size)); 1017} 1018 1019/* 1020 * Tell kern_execve.c about it, with a little help from the linker. 1021 */ 1022static struct execsw elf_execsw = {exec_elf_imgact, "ELF"}; 1023EXEC_SET(elf, elf_execsw); 1024