exec_elf32.c revision 1.13
1275970Scy/* $NetBSD: exec_elf32.c,v 1.13 1996/10/02 05:30:29 cgd Exp $ */ 2275970Scy 3275970Scy/* 4275970Scy * Copyright (c) 1996 Christopher G. Demetriou 5275970Scy * Copyright (c) 1994 Christos Zoulas 6275970Scy * All rights reserved. 7275970Scy * 8275970Scy * Redistribution and use in source and binary forms, with or without 9275970Scy * modification, are permitted provided that the following conditions 10275970Scy * are met: 11275970Scy * 1. Redistributions of source code must retain the above copyright 12275970Scy * notice, this list of conditions and the following disclaimer. 13275970Scy * 2. Redistributions in binary form must reproduce the above copyright 14275970Scy * notice, this list of conditions and the following disclaimer in the 15275970Scy * documentation and/or other materials provided with the distribution. 16275970Scy * 3. The name of the author may not be used to endorse or promote products 17275970Scy * derived from this software without specific prior written permission 18275970Scy * 19275970Scy * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20275970Scy * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21275970Scy * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22275970Scy * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23275970Scy * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24275970Scy * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25275970Scy * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26275970Scy * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27275970Scy * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28275970Scy * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29275970Scy */ 30275970Scy 31275970Scy/* If not included by exec_elf64.c, ELFSIZE won't be defined. */ 32275970Scy#ifndef ELFSIZE 33275970Scy#define ELFSIZE 32 34275970Scy#endif 35275970Scy 36275970Scy#include <sys/param.h> 37275970Scy#include <sys/systm.h> 38275970Scy#include <sys/kernel.h> 39275970Scy#include <sys/proc.h> 40275970Scy#include <sys/malloc.h> 41275970Scy#include <sys/namei.h> 42275970Scy#include <sys/vnode.h> 43275970Scy#include <sys/exec.h> 44275970Scy#include <sys/exec_elf.h> 45275970Scy#include <sys/fcntl.h> 46275970Scy#include <sys/syscall.h> 47275970Scy#include <sys/signalvar.h> 48275970Scy 49275970Scy#include <sys/mman.h> 50275970Scy#include <vm/vm.h> 51275970Scy#include <vm/vm_param.h> 52275970Scy#include <vm/vm_map.h> 53275970Scy 54275970Scy#include <machine/cpu.h> 55275970Scy#include <machine/reg.h> 56275970Scy#include <machine/exec.h> 57275970Scy 58275970Scy#ifdef COMPAT_LINUX 59275970Scy#include <compat/linux/linux_exec.h> 60275970Scy#endif 61275970Scy 62275970Scy#ifdef COMPAT_SVR4 63275970Scy#include <compat/svr4/svr4_exec.h> 64275970Scy#endif 65275970Scy 66275970Scy#define CONCAT(x,y) __CONCAT(x,y) 67275970Scy#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 68275970Scy#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 69275970Scy#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 70275970Scy#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 71275970Scy 72275970Scystatic int ELFNAME(check_header) __P((Elf_Ehdr *, int)); 73275970Scystatic int ELFNAME(load_file) __P((struct proc *, char *, 74275970Scy struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *)); 75275970Scystatic void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, 76275970Scy struct vnode *, Elf_Phdr *, Elf_Addr *, u_long *, int *)); 77275970Scy 78275970Scyextern char sigcode[], esigcode[]; 79275970Scy#ifdef SYSCALL_DEBUG 80275970Scyextern char *syscallnames[]; 81275970Scy#endif 82275970Scy 83275970Scystruct emul ELFNAMEEND(emul_netbsd) = { 84275970Scy "netbsd", 85275970Scy NULL, 86275970Scy sendsig, 87275970Scy SYS_syscall, 88275970Scy SYS_MAXSYSCALL, 89275970Scy sysent, 90275970Scy#ifdef SYSCALL_DEBUG 91275970Scy syscallnames, 92275970Scy#else 93275970Scy NULL, 94275970Scy#endif 95275970Scy ELF_AUX_ENTRIES * sizeof(AuxInfo), 96275970Scy ELFNAME(copyargs), 97275970Scy setregs, 98275970Scy sigcode, 99275970Scy esigcode, 100275970Scy}; 101275970Scy 102275970Scyint (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, 103275970Scy Elf_Ehdr *, char *, Elf_Addr *)) = { 104275970Scy#if defined(COMPAT_SVR4) && (ELFSIZE == 32) 105275970Scy ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ 106275970Scy#endif 107275970Scy#if defined(COMPAT_LINUX) && (ELFSIZE == 32) 108275970Scy ELFNAME2(linux,probe), /* XXX not 64-bit safe */ 109275970Scy#endif 110275970Scy}; 111275970Scy 112275970Scy#define ELF_ALIGN(a, b) ((a) & ~((b) - 1)) 113275970Scy 114275970Scy/* 115275970Scy * Copy arguments onto the stack in the normal way, but add some 116275970Scy * extra information in case of dynamic binding. 117275970Scy */ 118275970Scyvoid * 119275970ScyELFNAME(copyargs)(pack, arginfo, stack, argp) 120275970Scy struct exec_package *pack; 121275970Scy struct ps_strings *arginfo; 122275970Scy void *stack; 123275970Scy void *argp; 124275970Scy{ 125275970Scy size_t len; 126275970Scy AuxInfo ai[ELF_AUX_ENTRIES], *a; 127275970Scy struct elf_args *ap; 128275970Scy 129275970Scy stack = copyargs(pack, arginfo, stack, argp); 130275970Scy if (!stack) 131275970Scy return NULL; 132275970Scy 133275970Scy /* 134275970Scy * Push extra arguments on the stack needed by dynamically 135275970Scy * linked binaries 136275970Scy */ 137275970Scy if ((ap = (struct elf_args *) pack->ep_emul_arg)) { 138275970Scy a = ai; 139275970Scy 140275970Scy a->au_id = AUX_phdr; 141275970Scy a->au_v = ap->arg_phaddr; 142275970Scy a++; 143275970Scy 144275970Scy a->au_id = AUX_phent; 145275970Scy a->au_v = ap->arg_phentsize; 146275970Scy a++; 147275970Scy 148275970Scy a->au_id = AUX_phnum; 149275970Scy a->au_v = ap->arg_phnum; 150275970Scy a++; 151275970Scy 152275970Scy a->au_id = AUX_pagesz; 153275970Scy a->au_v = NBPG; 154275970Scy a++; 155275970Scy 156275970Scy a->au_id = AUX_base; 157275970Scy a->au_v = ap->arg_interp; 158275970Scy a++; 159275970Scy 160275970Scy a->au_id = AUX_flags; 161275970Scy a->au_v = 0; 162275970Scy a++; 163275970Scy 164275970Scy a->au_id = AUX_entry; 165275970Scy a->au_v = ap->arg_entry; 166275970Scy a++; 167 168 a->au_id = AUX_null; 169 a->au_v = 0; 170 a++; 171 172 free((char *) ap, M_TEMP); 173 pack->ep_emul_arg = NULL; 174 len = ELF_AUX_ENTRIES * sizeof (AuxInfo); 175 if (copyout(ai, stack, len)) 176 return NULL; 177 stack += len; 178 } 179 return stack; 180} 181 182/* 183 * elf_check_header(): 184 * 185 * Check header for validity; return 0 of ok ENOEXEC if error 186 * 187 * XXX machine type needs to be moved to <machine/param.h> so 188 * just one comparison can be done. Unfortunately, there is both 189 * em_486 and em_386, so this would not work on the i386. 190 */ 191static int 192ELFNAME(check_header)(eh, type) 193 Elf_Ehdr *eh; 194 int type; 195{ 196 197 if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) 198 return ENOEXEC; 199 200 switch (eh->e_machine) { 201 202 ELFDEFNNAME(MACHDEP_ID_CASES) 203 204 default: 205 return ENOEXEC; 206 } 207 208 if (eh->e_type != type) 209 return ENOEXEC; 210 211 return 0; 212} 213 214/* 215 * elf_load_psection(): 216 * 217 * Load a psection at the appropriate address 218 */ 219static void 220ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) 221 struct exec_vmcmd_set *vcset; 222 struct vnode *vp; 223 Elf_Phdr *ph; 224 Elf_Addr *addr; 225 u_long *size; 226 int *prot; 227{ 228 u_long uaddr, msize, psize, rm, rf; 229 long diff, offset; 230 231 /* 232 * If the user specified an address, then we load there. 233 */ 234 if (*addr != ELFDEFNNAME(NO_ADDR)) { 235 if (ph->p_align > 1) { 236 *addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align); 237 uaddr = ELF_ALIGN(ph->p_vaddr, ph->p_align); 238 } else 239 uaddr = ph->p_vaddr; 240 diff = ph->p_vaddr - uaddr; 241 } else { 242 *addr = uaddr = ph->p_vaddr; 243 if (ph->p_align > 1) 244 *addr = ELF_ALIGN(uaddr, ph->p_align); 245 diff = uaddr - *addr; 246 } 247 248 *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; 249 *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; 250 *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; 251 252 offset = ph->p_offset - diff; 253 *size = ph->p_filesz + diff; 254 msize = ph->p_memsz + diff; 255 psize = round_page(*size); 256 257 if ((ph->p_flags & Elf_pf_w) != 0) { 258 /* 259 * Because the pagedvn pager can't handle zero fill of the last 260 * data page if it's not page aligned we map the last page 261 * readvn. 262 */ 263 psize = trunc_page(*size); 264 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 265 offset, *prot); 266 if(psize != *size) 267 NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, 268 *addr + psize, vp, offset + psize, *prot); 269 } else 270 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 271 offset, *prot); 272 273 /* 274 * Check if we need to extend the size of the segment 275 */ 276 rm = round_page(*addr + msize); 277 rf = round_page(*addr + *size); 278 279 if (rm != rf) { 280 NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot); 281 *size = msize; 282 } 283} 284 285/* 286 * elf_read_from(): 287 * 288 * Read from vnode into buffer at offset. 289 */ 290int 291ELFNAME(read_from)(p, vp, off, buf, size) 292 struct vnode *vp; 293 u_long off; 294 struct proc *p; 295 caddr_t buf; 296 int size; 297{ 298 int error; 299 int resid; 300 301 if ((error = vn_rdwr(UIO_READ, vp, buf, size, 302 off, UIO_SYSSPACE, 0, p->p_ucred, 303 &resid, p)) != 0) 304 return error; 305 /* 306 * See if we got all of it 307 */ 308 if (resid != 0) 309 return ENOEXEC; 310 return 0; 311} 312 313/* 314 * elf_load_file(): 315 * 316 * Load a file (interpreter/library) pointed to by path 317 * [stolen from coff_load_shlib()]. Made slightly generic 318 * so it might be used externally. 319 */ 320static int 321ELFNAME(load_file)(p, path, vcset, entry, ap, last) 322 struct proc *p; 323 char *path; 324 struct exec_vmcmd_set *vcset; 325 u_long *entry; 326 struct elf_args *ap; 327 Elf_Addr *last; 328{ 329 int error, i; 330 struct nameidata nd; 331 Elf_Ehdr eh; 332 Elf_Phdr *ph = NULL; 333 u_long phsize; 334 char *bp = NULL; 335 Elf_Addr addr = *last; 336 337 bp = path; 338 /* 339 * 1. open file 340 * 2. read filehdr 341 * 3. map text, data, and bss out of it using VM_* 342 */ 343 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p); 344 if ((error = namei(&nd)) != 0) 345 return error; 346#ifdef notyet /* XXX cgd 960926 */ 347 XXX cgd 960926: check vnode type 348 XXX cgd 960926: check mount point for MNT_NOEXEC 349 XXX cgd 960926: check VOP_ACCESS on it. 350 XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?) 351#endif 352 VOP_UNLOCK(nd.ni_vp); 353 354 if ((error = ELFNAME(read_from)(p, nd.ni_vp, 0, (caddr_t) &eh, 355 sizeof(eh))) != 0) 356 goto bad; 357 358 if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) 359 goto bad; 360 361 phsize = eh.e_phnum * sizeof(Elf_Phdr); 362 ph = (Elf_Phdr *) malloc(phsize, M_TEMP, M_WAITOK); 363 364 if ((error = ELFNAME(read_from)(p, nd.ni_vp, eh.e_phoff, 365 (caddr_t) ph, phsize)) != 0) 366 goto bad; 367 368 /* 369 * Load all the necessary sections 370 */ 371 for (i = 0; i < eh.e_phnum; i++) { 372 u_long size = 0; 373 int prot = 0; 374 375 switch (ph[i].p_type) { 376 case Elf_pt_load: 377 ELFNAME(load_psection)(vcset, nd.ni_vp, &ph[i], &addr, 378 &size, &prot); 379 /* If entry is within this section it must be text */ 380 if (eh.e_entry >= ph[i].p_vaddr && 381 eh.e_entry < (ph[i].p_vaddr + size)) { 382 *entry = addr + eh.e_entry; 383 ap->arg_interp = addr; 384 } 385 addr += size; 386 break; 387 388 case Elf_pt_dynamic: 389 case Elf_pt_phdr: 390 case Elf_pt_note: 391 break; 392 393 default: 394 break; 395 } 396 } 397 398 free((char *) ph, M_TEMP); 399 *last = addr; 400 vrele(nd.ni_vp); 401 return 0; 402 403bad: 404 if (ph != NULL) 405 free((char *) ph, M_TEMP); 406#ifdef notyet /* XXX cgd 960926 */ 407 (maybe) VOP_CLOSE it 408#endif 409 vrele(nd.ni_vp); 410 return error; 411} 412 413/* 414 * exec_elf_makecmds(): Prepare an Elf binary's exec package 415 * 416 * First, set of the various offsets/lengths in the exec package. 417 * 418 * Then, mark the text image busy (so it can be demand paged) or error 419 * out if this is not possible. Finally, set up vmcmds for the 420 * text, data, bss, and stack segments. 421 */ 422int 423ELFNAME2(exec,makecmds)(p, epp) 424 struct proc *p; 425 struct exec_package *epp; 426{ 427 Elf_Ehdr *eh = epp->ep_hdr; 428 Elf_Phdr *ph, *pp; 429 Elf_Addr phdr = 0, pos = 0; 430 int error, i, n, nload; 431 char interp[MAXPATHLEN]; 432 u_long phsize; 433 434 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 435 return ENOEXEC; 436 437 if (ELFNAME(check_header)(eh, Elf_et_exec)) 438 return ENOEXEC; 439 440 /* 441 * check if vnode is in open for writing, because we want to 442 * demand-page out of it. if it is, don't do it, for various 443 * reasons 444 */ 445 if (epp->ep_vp->v_writecount != 0) { 446#ifdef DIAGNOSTIC 447 if (epp->ep_vp->v_flag & VTEXT) 448 panic("exec: a VTEXT vnode has writecount != 0\n"); 449#endif 450 return ETXTBSY; 451 } 452 /* 453 * Allocate space to hold all the program headers, and read them 454 * from the file 455 */ 456 phsize = eh->e_phnum * sizeof(Elf_Phdr); 457 ph = (Elf_Phdr *) malloc(phsize, M_TEMP, M_WAITOK); 458 459 if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, 460 (caddr_t) ph, phsize)) != 0) 461 goto bad; 462 463 epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 464 epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 465 466 interp[0] = '\0'; 467 468 for (i = 0; i < eh->e_phnum; i++) { 469 pp = &ph[i]; 470 if (pp->p_type == Elf_pt_interp) { 471 if (pp->p_filesz >= sizeof(interp)) 472 goto bad; 473 if ((error = ELFNAME(read_from)(p, epp->ep_vp, pp->p_offset, 474 (caddr_t) interp, pp->p_filesz)) != 0) 475 goto bad; 476 break; 477 } 478 } 479 480 /* 481 * Setup things for native emulation. 482 */ 483 epp->ep_emul = &ELFNAMEEND(emul_netbsd); 484 pos = ELFDEFNNAME(NO_ADDR); 485 486 /* 487 * On the same architecture, we may be emulating different systems. 488 * See which one will accept this executable. This currently only 489 * applies to Linux and SVR4 on the i386. 490 * 491 * Probe functions would normally see if the interpreter (if any) 492 * exists. Emulation packages may possibly replace the interpreter in 493 * interp[] with a changed path (/emul/xxx/<path>), and also 494 * set the ep_emul field in the exec package structure. 495 */ 496 if ((n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0])) { 497 error = ENOEXEC; 498 for (i = 0; i < n && error; i++) 499 error = ELFNAME(probe_funcs)[i](p, epp, eh, interp, &pos); 500 501#ifdef notyet 502 /* 503 * We should really use a signature in our native binaries 504 * and have our own probe function for matching binaries, 505 * before trying the emulations. For now, if the emulation 506 * probes failed we default to native. 507 */ 508 if (error) 509 goto bad; 510#endif 511 } 512 513 /* 514 * Load all the necessary sections 515 */ 516 for (i = nload = 0; i < eh->e_phnum; i++) { 517 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 518 u_long size = 0; 519 int prot = 0; 520 521 pp = &ph[i]; 522 523 switch (ph[i].p_type) { 524 case Elf_pt_load: 525 /* 526 * XXX 527 * Can handle only 2 sections: text and data 528 */ 529 if (nload++ == 2) 530 goto bad; 531 ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, 532 &ph[i], &addr, &size, &prot); 533 /* 534 * Decide whether it's text or data by looking 535 * at the entry point. 536 */ 537 if (eh->e_entry >= addr && eh->e_entry < (addr + size)){ 538 epp->ep_taddr = addr; 539 epp->ep_tsize = size; 540 } else { 541 epp->ep_daddr = addr; 542 epp->ep_dsize = size; 543 } 544 break; 545 546 case Elf_pt_shlib: 547 error = ENOEXEC; 548 goto bad; 549 550 case Elf_pt_interp: 551 /* Already did this one */ 552 case Elf_pt_dynamic: 553 case Elf_pt_note: 554 break; 555 556 case Elf_pt_phdr: 557 /* Note address of program headers (in text segment) */ 558 phdr = pp->p_vaddr; 559 break; 560 561 default: 562 /* 563 * Not fatal; we don't need to understand everything. 564 */ 565 break; 566 } 567 } 568 569 /* 570 * If no position to load the interpreter was set by a probe 571 * function, pick the same address that a non-fixed mmap(0, ..) 572 * would (i.e. something safely out of the way). 573 */ 574 if (pos == ELFDEFNNAME(NO_ADDR) && 575 epp->ep_emul == &ELFNAMEEND(emul_netbsd)) 576 pos = round_page(epp->ep_daddr + MAXDSIZ); 577 578 /* 579 * Check if we found a dynamically linked binary and arrange to load 580 * it's interpreter 581 */ 582 if (interp[0]) { 583 struct elf_args *ap; 584 585 ap = (struct elf_args *) malloc(sizeof(struct elf_args), 586 M_TEMP, M_WAITOK); 587 if ((error = ELFNAME(load_file)(p, interp, &epp->ep_vmcmds, 588 &epp->ep_entry, ap, &pos)) != 0) { 589 free((char *) ap, M_TEMP); 590 goto bad; 591 } 592 pos += phsize; 593 ap->arg_phaddr = phdr; 594 595 ap->arg_phentsize = eh->e_phentsize; 596 ap->arg_phnum = eh->e_phnum; 597 ap->arg_entry = eh->e_entry; 598 599 epp->ep_emul_arg = ap; 600 } else 601 epp->ep_entry = eh->e_entry; 602 603#ifdef ELF_MAP_PAGE_ZERO 604 /* Dell SVR4 maps page zero, yeuch! */ 605 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, 606 VM_PROT_READ); 607#endif 608 free((char *) ph, M_TEMP); 609 epp->ep_vp->v_flag |= VTEXT; 610 return exec_elf_setup_stack(p, epp); 611 612bad: 613 free((char *) ph, M_TEMP); 614 kill_vmcmds(&epp->ep_vmcmds); 615 return ENOEXEC; 616} 617