exec_elf32.c revision 1.10
1/* $NetBSD: exec_elf32.c,v 1.10 1996/09/26 21:50:56 cgd Exp $ */ 2 3/* 4 * Copyright (c) 1996 Christopher G. Demetriou 5 * Copyright (c) 1994 Christos Zoulas 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31/* If not included by exec_elf64.c, ELFSIZE won't be defined. */ 32#ifndef ELFSIZE 33#define ELFSIZE 32 34#endif 35 36#if defined(COMPAT_SVR4) || defined(COMPAT_LINUX) /* XXX should die */ 37#undef EXEC_ELF32 /* XXX should die */ 38#define EXEC_ELF32 /* XXX should die */ 39#endif /* XXX should die */ 40 41#include <sys/param.h> 42#include <sys/systm.h> 43#include <sys/kernel.h> 44#include <sys/proc.h> 45#include <sys/malloc.h> 46#include <sys/namei.h> 47#include <sys/vnode.h> 48#include <sys/exec.h> 49#include <sys/exec_elf.h> 50#include <sys/fcntl.h> 51#include <sys/syscall.h> 52#include <sys/signalvar.h> 53 54#include <sys/mman.h> 55#include <vm/vm.h> 56#include <vm/vm_param.h> 57#include <vm/vm_map.h> 58 59#include <machine/cpu.h> 60#include <machine/reg.h> 61#include <machine/exec.h> 62 63#ifdef COMPAT_LINUX 64#include <compat/linux/linux_exec.h> 65#endif 66 67#ifdef COMPAT_SVR4 68#include <compat/svr4/svr4_exec.h> 69#endif 70 71#define CONCAT(x,y) __CONCAT(x,y) 72#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x))) 73#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y)))) 74#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE)) 75#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x))) 76 77int ELFNAME(check_header) __P((Elf_Ehdr *, int)); 78int ELFNAME(load_file) __P((struct proc *, char *, struct exec_vmcmd_set *, 79 u_long *, struct elf_args *, Elf_Addr *)); 80static void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, 81 struct vnode *, Elf_Phdr *, Elf_Addr *, u_long *, int *)); 82 83extern char sigcode[], esigcode[]; 84#ifdef SYSCALL_DEBUG 85extern char *syscallnames[]; 86#endif 87 88struct emul ELFNAMEEND(emul_netbsd) = { 89 "netbsd", 90 NULL, 91 sendsig, 92 SYS_syscall, 93 SYS_MAXSYSCALL, 94 sysent, 95#ifdef SYSCALL_DEBUG 96 syscallnames, 97#else 98 NULL, 99#endif 100 ELF_AUX_ENTRIES * sizeof(AuxInfo), 101 ELFNAME(copyargs), 102 setregs, 103 sigcode, 104 esigcode, 105}; 106 107int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *, 108 Elf_Ehdr *, char *, Elf_Addr *)) = { 109#if defined(COMPAT_SVR4) && (ELFSIZE == 32) 110 ELFNAME2(svr4,probe), /* XXX not 64-bit safe */ 111#endif 112#if defined(COMPAT_LINUX) && (ELFSIZE == 32) 113 ELFNAME2(linux,probe), /* XXX not 64-bit safe */ 114#endif 115}; 116 117#define ELF_ALIGN(a, b) ((a) & ~((b) - 1)) 118 119/* 120 * Copy arguments onto the stack in the normal way, but add some 121 * extra information in case of dynamic binding. 122 */ 123void * 124ELFNAME(copyargs)(pack, arginfo, stack, argp) 125 struct exec_package *pack; 126 struct ps_strings *arginfo; 127 void *stack; 128 void *argp; 129{ 130 size_t len; 131 AuxInfo ai[ELF_AUX_ENTRIES], *a; 132 struct elf_args *ap; 133 134 stack = copyargs(pack, arginfo, stack, argp); 135 if (!stack) 136 return NULL; 137 138 /* 139 * Push extra arguments on the stack needed by dynamically 140 * linked binaries 141 */ 142 if ((ap = (struct elf_args *) pack->ep_emul_arg)) { 143 a = ai; 144 145 a->au_id = AUX_phdr; 146 a->au_v = ap->arg_phaddr; 147 a++; 148 149 a->au_id = AUX_phent; 150 a->au_v = ap->arg_phentsize; 151 a++; 152 153 a->au_id = AUX_phnum; 154 a->au_v = ap->arg_phnum; 155 a++; 156 157 a->au_id = AUX_pagesz; 158 a->au_v = NBPG; 159 a++; 160 161 a->au_id = AUX_base; 162 a->au_v = ap->arg_interp; 163 a++; 164 165 a->au_id = AUX_flags; 166 a->au_v = 0; 167 a++; 168 169 a->au_id = AUX_entry; 170 a->au_v = ap->arg_entry; 171 a++; 172 173 a->au_id = AUX_null; 174 a->au_v = 0; 175 a++; 176 177 free((char *) ap, M_TEMP); 178 pack->ep_emul_arg = NULL; 179 len = ELF_AUX_ENTRIES * sizeof (AuxInfo); 180 if (copyout(ai, stack, len)) 181 return NULL; 182 stack += len; 183 } 184 return stack; 185} 186 187/* 188 * elf_check_header(): 189 * 190 * Check header for validity; return 0 of ok ENOEXEC if error 191 * 192 * XXX machine type needs to be moved to <machine/param.h> so 193 * just one comparison can be done. Unfortunately, there is both 194 * em_486 and em_386, so this would not work on the i386. 195 */ 196int 197ELFNAME(check_header)(eh, type) 198 Elf_Ehdr *eh; 199 int type; 200{ 201 202 if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0) 203 return ENOEXEC; 204 205 switch (eh->e_machine) { 206 207 ELFDEFNNAME(MACHDEP_ID_CASES) 208 209 default: 210 return ENOEXEC; 211 } 212 213 if (eh->e_type != type) 214 return ENOEXEC; 215 216 return 0; 217} 218 219/* 220 * elf_load_psection(): 221 * 222 * Load a psection at the appropriate address 223 */ 224static void 225ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot) 226 struct exec_vmcmd_set *vcset; 227 struct vnode *vp; 228 Elf_Phdr *ph; 229 Elf_Addr *addr; 230 u_long *size; 231 int *prot; 232{ 233 u_long uaddr, msize, psize, rm, rf; 234 long diff, offset; 235 236 /* 237 * If the user specified an address, then we load there. 238 */ 239 if (*addr != ELFDEFNNAME(NO_ADDR)) { 240 if (ph->p_align > 1) { 241 *addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align); 242 uaddr = ELF_ALIGN(ph->p_vaddr, ph->p_align); 243 } else 244 uaddr = ph->p_vaddr; 245 diff = ph->p_vaddr - uaddr; 246 } else { 247 *addr = uaddr = ph->p_vaddr; 248 if (ph->p_align > 1) 249 *addr = ELF_ALIGN(uaddr, ph->p_align); 250 diff = uaddr - *addr; 251 } 252 253 *prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0; 254 *prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0; 255 *prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0; 256 257 offset = ph->p_offset - diff; 258 *size = ph->p_filesz + diff; 259 msize = ph->p_memsz + diff; 260 psize = round_page(*size); 261 262 if ((ph->p_flags & Elf_pf_w) != 0) { 263 /* 264 * Because the pagedvn pager can't handle zero fill of the last 265 * data page if it's not page aligned we map the last page 266 * readvn. 267 */ 268 psize = trunc_page(*size); 269 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 270 offset, *prot); 271 if(psize != *size) 272 NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize, 273 *addr + psize, vp, offset + psize, *prot); 274 } else 275 NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp, 276 offset, *prot); 277 278 /* 279 * Check if we need to extend the size of the segment 280 */ 281 rm = round_page(*addr + msize); 282 rf = round_page(*addr + *size); 283 284 if (rm != rf) { 285 NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot); 286 *size = msize; 287 } 288} 289 290/* 291 * elf_read_from(): 292 * 293 * Read from vnode into buffer at offset. 294 */ 295int 296ELFNAME(read_from)(p, vp, off, buf, size) 297 struct vnode *vp; 298 u_long off; 299 struct proc *p; 300 caddr_t buf; 301 int size; 302{ 303 int error; 304 int resid; 305 306 if ((error = vn_rdwr(UIO_READ, vp, buf, size, 307 off, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, 308 &resid, p)) != 0) 309 return error; 310 /* 311 * See if we got all of it 312 */ 313 if (resid != 0) 314 return ENOEXEC; 315 return 0; 316} 317 318/* 319 * elf_load_file(): 320 * 321 * Load a file (interpreter/library) pointed to by path 322 * [stolen from coff_load_shlib()]. Made slightly generic 323 * so it might be used externally. 324 */ 325int 326ELFNAME(load_file)(p, path, vcset, entry, ap, last) 327 struct proc *p; 328 char *path; 329 struct exec_vmcmd_set *vcset; 330 u_long *entry; 331 struct elf_args *ap; 332 Elf_Addr *last; 333{ 334 int error, i; 335 struct nameidata nd; 336 Elf_Ehdr eh; 337 Elf_Phdr *ph = NULL; 338 u_long phsize; 339 char *bp = NULL; 340 Elf_Addr addr = *last; 341 342 bp = path; 343 /* 344 * 1. open file 345 * 2. read filehdr 346 * 3. map text, data, and bss out of it using VM_* 347 */ 348 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, p); 349 if ((error = namei(&nd)) != 0) { 350 return error; 351 } 352 if ((error = ELFNAME(read_from)(p, nd.ni_vp, 0, (caddr_t) &eh, 353 sizeof(eh))) != 0) 354 goto bad; 355 356 if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0) 357 goto bad; 358 359 phsize = eh.e_phnum * sizeof(Elf_Phdr); 360 ph = (Elf_Phdr *) malloc(phsize, M_TEMP, M_WAITOK); 361 362 if ((error = ELFNAME(read_from)(p, nd.ni_vp, eh.e_phoff, 363 (caddr_t) ph, phsize)) != 0) 364 goto bad; 365 366 /* 367 * Load all the necessary sections 368 */ 369 for (i = 0; i < eh.e_phnum; i++) { 370 u_long size = 0; 371 int prot = 0; 372 373 switch (ph[i].p_type) { 374 case Elf_pt_load: 375 ELFNAME(load_psection)(vcset, nd.ni_vp, &ph[i], &addr, 376 &size, &prot); 377 /* If entry is within this section it must be text */ 378 if (eh.e_entry >= ph[i].p_vaddr && 379 eh.e_entry < (ph[i].p_vaddr + size)) { 380 *entry = addr + eh.e_entry; 381 ap->arg_interp = addr; 382 } 383 addr += size; 384 break; 385 386 case Elf_pt_dynamic: 387 case Elf_pt_phdr: 388 case Elf_pt_note: 389 break; 390 391 default: 392 break; 393 } 394 } 395 396bad: 397 if (ph != NULL) 398 free((char *) ph, M_TEMP); 399 400 *last = addr; 401 vrele(nd.ni_vp); 402 return error; 403} 404 405/* 406 * exec_elf_makecmds(): Prepare an Elf binary's exec package 407 * 408 * First, set of the various offsets/lengths in the exec package. 409 * 410 * Then, mark the text image busy (so it can be demand paged) or error 411 * out if this is not possible. Finally, set up vmcmds for the 412 * text, data, bss, and stack segments. 413 */ 414int 415ELFNAME2(exec,makecmds)(p, epp) 416 struct proc *p; 417 struct exec_package *epp; 418{ 419 Elf_Ehdr *eh = epp->ep_hdr; 420 Elf_Phdr *ph, *pp; 421 Elf_Addr phdr = 0, pos = 0; 422 int error, i, n, nload; 423 char interp[MAXPATHLEN]; 424 u_long phsize; 425 426 if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) 427 return ENOEXEC; 428 429 if (ELFNAME(check_header)(eh, Elf_et_exec)) 430 return ENOEXEC; 431 432 /* 433 * check if vnode is in open for writing, because we want to 434 * demand-page out of it. if it is, don't do it, for various 435 * reasons 436 */ 437 if (epp->ep_vp->v_writecount != 0) { 438#ifdef DIAGNOSTIC 439 if (epp->ep_vp->v_flag & VTEXT) 440 panic("exec: a VTEXT vnode has writecount != 0\n"); 441#endif 442 return ETXTBSY; 443 } 444 /* 445 * Allocate space to hold all the program headers, and read them 446 * from the file 447 */ 448 phsize = eh->e_phnum * sizeof(Elf_Phdr); 449 ph = (Elf_Phdr *) malloc(phsize, M_TEMP, M_WAITOK); 450 451 if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, 452 (caddr_t) ph, phsize)) != 0) 453 goto bad; 454 455 epp->ep_tsize = ELFDEFNNAME(NO_ADDR); 456 epp->ep_dsize = ELFDEFNNAME(NO_ADDR); 457 458 interp[0] = '\0'; 459 460 for (i = 0; i < eh->e_phnum; i++) { 461 pp = &ph[i]; 462 if (pp->p_type == Elf_pt_interp) { 463 if (pp->p_filesz >= sizeof(interp)) 464 goto bad; 465 if ((error = ELFNAME(read_from)(p, epp->ep_vp, pp->p_offset, 466 (caddr_t) interp, pp->p_filesz)) != 0) 467 goto bad; 468 break; 469 } 470 } 471 472 /* 473 * Setup things for native emulation. 474 */ 475 epp->ep_emul = &ELFNAMEEND(emul_netbsd); 476 pos = ELFDEFNNAME(NO_ADDR); 477 478 /* 479 * On the same architecture, we may be emulating different systems. 480 * See which one will accept this executable. This currently only 481 * applies to Linux and SVR4 on the i386. 482 * 483 * Probe functions would normally see if the interpreter (if any) 484 * exists. Emulation packages may possibly replace the interpreter in 485 * interp[] with a changed path (/emul/xxx/<path>), and also 486 * set the ep_emul field in the exec package structure. 487 */ 488 if ((n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0])) { 489 error = ENOEXEC; 490 for (i = 0; i < n && error; i++) 491 error = ELFNAME(probe_funcs)[i](p, epp, eh, interp, &pos); 492 493#ifdef notyet 494 /* 495 * We should really use a signature in our native binaries 496 * and have our own probe function for matching binaries, 497 * before trying the emulations. For now, if the emulation 498 * probes failed we default to native. 499 */ 500 if (error) 501 goto bad; 502#endif 503 } 504 505 /* 506 * Load all the necessary sections 507 */ 508 for (i = nload = 0; i < eh->e_phnum; i++) { 509 Elf_Addr addr = ELFDEFNNAME(NO_ADDR); 510 u_long size = 0; 511 int prot = 0; 512 513 pp = &ph[i]; 514 515 switch (ph[i].p_type) { 516 case Elf_pt_load: 517 /* 518 * XXX 519 * Can handle only 2 sections: text and data 520 */ 521 if (nload++ == 2) 522 goto bad; 523 ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp, 524 &ph[i], &addr, &size, &prot); 525 /* 526 * Decide whether it's text or data by looking 527 * at the entry point. 528 */ 529 if (eh->e_entry >= addr && eh->e_entry < (addr + size)){ 530 epp->ep_taddr = addr; 531 epp->ep_tsize = size; 532 } else { 533 epp->ep_daddr = addr; 534 epp->ep_dsize = size; 535 } 536 break; 537 538 case Elf_pt_shlib: 539 error = ENOEXEC; 540 goto bad; 541 542 case Elf_pt_interp: 543 /* Already did this one */ 544 case Elf_pt_dynamic: 545 case Elf_pt_note: 546 break; 547 548 case Elf_pt_phdr: 549 /* Note address of program headers (in text segment) */ 550 phdr = pp->p_vaddr; 551 break; 552 553 default: 554 /* 555 * Not fatal; we don't need to understand everything. 556 */ 557 break; 558 } 559 } 560 561 /* 562 * If no position to load the interpreter was set by a probe 563 * function, pick the same address that a non-fixed mmap(0, ..) 564 * would (i.e. something safely out of the way). 565 */ 566 if (pos == ELFDEFNNAME(NO_ADDR) && 567 epp->ep_emul == &ELFNAMEEND(emul_netbsd)) 568 pos = round_page(epp->ep_daddr + MAXDSIZ); 569 570 /* 571 * Check if we found a dynamically linked binary and arrange to load 572 * it's interpreter 573 */ 574 if (interp[0]) { 575 struct elf_args *ap; 576 577 ap = (struct elf_args *) malloc(sizeof(struct elf_args), 578 M_TEMP, M_WAITOK); 579 if ((error = ELFNAME(load_file)(p, interp, &epp->ep_vmcmds, 580 &epp->ep_entry, ap, &pos)) != 0) { 581 free((char *) ap, M_TEMP); 582 goto bad; 583 } 584 pos += phsize; 585 ap->arg_phaddr = phdr; 586 587 ap->arg_phentsize = eh->e_phentsize; 588 ap->arg_phnum = eh->e_phnum; 589 ap->arg_entry = eh->e_entry; 590 591 epp->ep_emul_arg = ap; 592 } else 593 epp->ep_entry = eh->e_entry; 594 595#ifdef ELF_MAP_PAGE_ZERO 596 /* Dell SVR4 maps page zero, yeuch! */ 597 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0, 598 VM_PROT_READ); 599#endif 600 free((char *) ph, M_TEMP); 601 epp->ep_vp->v_flag |= VTEXT; 602 return exec_elf_setup_stack(p, epp); 603 604bad: 605 free((char *) ph, M_TEMP); 606 kill_vmcmds(&epp->ep_vmcmds); 607 return ENOEXEC; 608} 609