linux_exec_elf32.c revision 1.24
1 /* $NetBSD: linux_exec_elf32.c,v 1.24 1996/10/10 17:51:56 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Frank van der Linden 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 * based on exec_aout.c, sunos_exec.c and svr4_exec.c 31 */ 32 33 #define ELFSIZE 32 /* XXX should die */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/proc.h> 39 #include <sys/malloc.h> 40 #include <sys/namei.h> 41 #include <sys/vnode.h> 42 #include <sys/mount.h> 43 #include <sys/exec_elf.h> 44 45 #include <sys/mman.h> 46 #include <sys/syscallargs.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #include <vm/vm_map.h> 51 52 #include <machine/cpu.h> 53 #include <machine/reg.h> 54 #include <machine/linux_machdep.h> 55 56 #include <compat/linux/linux_types.h> 57 #include <compat/linux/linux_syscall.h> 58 #include <compat/linux/linux_signal.h> 59 #include <compat/linux/linux_syscallargs.h> 60 #include <compat/linux/linux_util.h> 61 #include <compat/linux/linux_exec.h> 62 63 static void *linux_aout_copyargs __P((struct exec_package *, 64 struct ps_strings *, void *, void *)); 65 static int linux_elf32_signature __P((struct proc *p, struct exec_package *, 66 Elf32_Ehdr *)); 67 68 #define LINUX_AOUT_AUX_ARGSIZ 2 69 #define LINUX_ELF_AUX_ARGSIZ (sizeof(AuxInfo) * 8 / sizeof(char *)) 70 71 72 const char linux_emul_path[] = "/emul/linux"; 73 extern int linux_error[]; 74 extern char linux_sigcode[], linux_esigcode[]; 75 extern struct sysent linux_sysent[]; 76 extern char *linux_syscallnames[]; 77 78 int exec_linux_aout_prep_zmagic __P((struct proc *, struct exec_package *)); 79 int exec_linux_aout_prep_nmagic __P((struct proc *, struct exec_package *)); 80 int exec_linux_aout_prep_omagic __P((struct proc *, struct exec_package *)); 81 int exec_linux_aout_prep_qmagic __P((struct proc *, struct exec_package *)); 82 83 struct emul emul_linux_aout = { 84 "linux", 85 linux_error, 86 linux_sendsig, 87 LINUX_SYS_syscall, 88 LINUX_SYS_MAXSYSCALL, 89 linux_sysent, 90 linux_syscallnames, 91 LINUX_AOUT_AUX_ARGSIZ, 92 linux_aout_copyargs, 93 setregs, 94 linux_sigcode, 95 linux_esigcode, 96 }; 97 98 struct emul emul_linux_elf = { 99 "linux", 100 linux_error, 101 linux_sendsig, 102 LINUX_SYS_syscall, 103 LINUX_SYS_MAXSYSCALL, 104 linux_sysent, 105 linux_syscallnames, 106 LINUX_ELF_AUX_ARGSIZ, 107 elf32_copyargs, 108 setregs, 109 linux_sigcode, 110 linux_esigcode, 111 }; 112 113 114 static void * 115 linux_aout_copyargs(pack, arginfo, stack, argp) 116 struct exec_package *pack; 117 struct ps_strings *arginfo; 118 void *stack; 119 void *argp; 120 { 121 char **cpp = stack; 122 char **stk = stack; 123 char *dp, *sp; 124 size_t len; 125 void *nullp = NULL; 126 int argc = arginfo->ps_nargvstr; 127 int envc = arginfo->ps_nenvstr; 128 129 if (copyout(&argc, cpp++, sizeof(argc))) 130 return NULL; 131 132 /* leave room for envp and argv */ 133 cpp += 2; 134 if (copyout(&cpp, &stk[1], sizeof (cpp))) 135 return NULL; 136 137 dp = (char *) (cpp + argc + envc + 2); 138 sp = argp; 139 140 /* XXX don't copy them out, remap them! */ 141 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 142 143 for (; --argc >= 0; sp += len, dp += len) 144 if (copyout(&dp, cpp++, sizeof(dp)) || 145 copyoutstr(sp, dp, ARG_MAX, &len)) 146 return NULL; 147 148 if (copyout(&nullp, cpp++, sizeof(nullp))) 149 return NULL; 150 151 if (copyout(&cpp, &stk[2], sizeof (cpp))) 152 return NULL; 153 154 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 155 156 for (; --envc >= 0; sp += len, dp += len) 157 if (copyout(&dp, cpp++, sizeof(dp)) || 158 copyoutstr(sp, dp, ARG_MAX, &len)) 159 return NULL; 160 161 if (copyout(&nullp, cpp++, sizeof(nullp))) 162 return NULL; 163 164 return cpp; 165 } 166 167 int 168 exec_linux_aout_makecmds(p, epp) 169 struct proc *p; 170 struct exec_package *epp; 171 { 172 struct exec *linux_ep = epp->ep_hdr; 173 int machtype, magic; 174 int error = ENOEXEC; 175 176 magic = LINUX_N_MAGIC(linux_ep); 177 machtype = LINUX_N_MACHTYPE(linux_ep); 178 179 180 if (machtype != LINUX_MID_MACHINE) 181 return (ENOEXEC); 182 183 switch (magic) { 184 case QMAGIC: 185 error = exec_linux_aout_prep_qmagic(p, epp); 186 break; 187 case ZMAGIC: 188 error = exec_linux_aout_prep_zmagic(p, epp); 189 break; 190 case NMAGIC: 191 error = exec_linux_aout_prep_nmagic(p, epp); 192 break; 193 case OMAGIC: 194 error = exec_linux_aout_prep_omagic(p, epp); 195 break; 196 } 197 if (error == 0) 198 epp->ep_emul = &emul_linux_aout; 199 return error; 200 } 201 202 /* 203 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400 204 * is very likely not page aligned on most architectures, it is treated 205 * as an NMAGIC here. XXX 206 */ 207 208 int 209 exec_linux_aout_prep_zmagic(p, epp) 210 struct proc *p; 211 struct exec_package *epp; 212 { 213 struct exec *execp = epp->ep_hdr; 214 215 epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC); 216 epp->ep_tsize = execp->a_text; 217 epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC); 218 epp->ep_dsize = execp->a_data + execp->a_bss; 219 epp->ep_entry = execp->a_entry; 220 221 /* set up command for text segment */ 222 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 223 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC), 224 VM_PROT_READ|VM_PROT_EXECUTE); 225 226 /* set up command for data segment */ 227 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 228 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC), 229 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 230 231 /* set up command for bss segment */ 232 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 233 epp->ep_daddr + execp->a_data, NULLVP, 0, 234 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 235 236 return exec_aout_setup_stack(p, epp); 237 } 238 239 /* 240 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package. 241 * Not different from the normal stuff. 242 */ 243 244 int 245 exec_linux_aout_prep_nmagic(p, epp) 246 struct proc *p; 247 struct exec_package *epp; 248 { 249 struct exec *execp = epp->ep_hdr; 250 long bsize, baddr; 251 252 epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC); 253 epp->ep_tsize = execp->a_text; 254 epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC); 255 epp->ep_dsize = execp->a_data + execp->a_bss; 256 epp->ep_entry = execp->a_entry; 257 258 /* set up command for text segment */ 259 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 260 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC), 261 VM_PROT_READ|VM_PROT_EXECUTE); 262 263 /* set up command for data segment */ 264 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 265 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC), 266 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 267 268 /* set up command for bss segment */ 269 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 270 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 271 if (bsize > 0) 272 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 273 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 274 275 return exec_aout_setup_stack(p, epp); 276 } 277 278 /* 279 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package. 280 * Business as usual. 281 */ 282 283 int 284 exec_linux_aout_prep_omagic(p, epp) 285 struct proc *p; 286 struct exec_package *epp; 287 { 288 struct exec *execp = epp->ep_hdr; 289 long dsize, bsize, baddr; 290 291 epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC); 292 epp->ep_tsize = execp->a_text; 293 epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC); 294 epp->ep_dsize = execp->a_data + execp->a_bss; 295 epp->ep_entry = execp->a_entry; 296 297 /* set up command for text and data segments */ 298 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 299 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 300 LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 301 302 /* set up command for bss segment */ 303 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 304 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 305 if (bsize > 0) 306 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 307 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 308 309 /* 310 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 311 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 312 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 313 * respectively to page boundaries. 314 * Compensate `ep_dsize' for the amount of data covered by the last 315 * text page. 316 */ 317 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 318 epp->ep_dsize = (dsize > 0) ? dsize : 0; 319 return exec_aout_setup_stack(p, epp); 320 } 321 322 int 323 exec_linux_aout_prep_qmagic(p, epp) 324 struct proc *p; 325 struct exec_package *epp; 326 { 327 struct exec *execp = epp->ep_hdr; 328 329 epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC); 330 epp->ep_tsize = execp->a_text; 331 epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC); 332 epp->ep_dsize = execp->a_data + execp->a_bss; 333 epp->ep_entry = execp->a_entry; 334 335 /* 336 * check if vnode is in open for writing, because we want to 337 * demand-page out of it. if it is, don't do it, for various 338 * reasons 339 */ 340 if ((execp->a_text != 0 || execp->a_data != 0) && 341 epp->ep_vp->v_writecount != 0) { 342 #ifdef DIAGNOSTIC 343 if (epp->ep_vp->v_flag & VTEXT) 344 panic("exec: a VTEXT vnode has writecount != 0\n"); 345 #endif 346 return ETXTBSY; 347 } 348 epp->ep_vp->v_flag |= VTEXT; 349 350 /* set up command for text segment */ 351 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text, 352 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC), 353 VM_PROT_READ|VM_PROT_EXECUTE); 354 355 /* set up command for data segment */ 356 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data, 357 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC), 358 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 359 360 /* set up command for bss segment */ 361 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 362 epp->ep_daddr + execp->a_data, NULLVP, 0, 363 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 364 365 return exec_aout_setup_stack(p, epp); 366 } 367 368 /* 369 * Take advantage of the fact that all the linux binaries are compiled 370 * with gcc, and gcc sticks in the comment field a signature. Note that 371 * on SVR4 binaries, the gcc signature will follow the OS name signature, 372 * that will not be a problem. We don't bother to read in the string table, 373 * but we check all the progbits headers. 374 */ 375 static int 376 linux_elf32_signature(p, epp, eh) 377 struct proc *p; 378 struct exec_package *epp; 379 Elf32_Ehdr *eh; 380 { 381 size_t shsize = sizeof(Elf32_Shdr) * eh->e_shnum; 382 size_t i; 383 static const char signature[] = "\0GCC: (GNU) "; 384 char buf[sizeof(signature) - 1]; 385 Elf32_Shdr *sh; 386 int error; 387 388 sh = (Elf32_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 389 390 if ((error = elf32_read_from(p, epp->ep_vp, eh->e_shoff, 391 (caddr_t) sh, shsize)) != 0) 392 goto out; 393 394 for (i = 0; i < eh->e_shnum; i++) { 395 Elf32_Shdr *s = &sh[i]; 396 397 /* 398 * Identify candidates for the comment header; 399 * Header cannot have a load address, or flags and 400 * it must be large enough. 401 */ 402 if (s->sh_type != Elf_sht_progbits || 403 s->sh_addr != 0 || 404 s->sh_flags != 0 || 405 s->sh_size < sizeof(signature) - 1) 406 continue; 407 408 if ((error = elf32_read_from(p, epp->ep_vp, s->sh_offset, 409 (caddr_t) buf, sizeof(signature) - 1)) != 0) 410 goto out; 411 412 /* 413 * error is 0, if the signatures match we are done. 414 */ 415 if (bcmp(buf, signature, sizeof(signature) - 1) == 0) 416 goto out; 417 } 418 error = EFTYPE; 419 420 out: 421 free(sh, M_TEMP); 422 return error; 423 } 424 425 int 426 linux_elf32_probe(p, epp, eh, itp, pos) 427 struct proc *p; 428 struct exec_package *epp; 429 Elf32_Ehdr *eh; 430 char *itp; 431 Elf32_Addr *pos; 432 { 433 char *bp; 434 int error; 435 size_t len; 436 437 if ((error = linux_elf32_signature(p, epp, eh)) != 0) 438 return error; 439 440 if (itp[0]) { 441 if ((error = emul_find(p, NULL, linux_emul_path, itp, &bp, 0))) 442 return error; 443 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 444 return error; 445 free(bp, M_TEMP); 446 } 447 epp->ep_emul = &emul_linux_elf; 448 *pos = ELF32_NO_ADDR; 449 return 0; 450 } 451 452 /* 453 * The Linux system call to load shared libraries, a.out version. The 454 * a.out shared libs are just files that are mapped onto a fixed 455 * address in the process' address space. The address is given in 456 * a_entry. Read in the header, set up some VM commands and run them. 457 * 458 * Yes, both text and data are mapped at once, so we're left with 459 * writeable text for the shared libs. The Linux crt0 seemed to break 460 * sometimes when data was mapped seperately. It munmapped a uselib() 461 * of ld.so by hand, which failed with shared text and data for ld.so 462 * Yuck. 463 * 464 * Because of the problem with ZMAGIC executables (text starts 465 * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC 466 * shared libs are not handled very efficiently :-( 467 */ 468 469 int 470 linux_sys_uselib(p, v, retval) 471 struct proc *p; 472 void *v; 473 register_t *retval; 474 { 475 struct linux_sys_uselib_args /* { 476 syscallarg(char *) path; 477 } */ *uap = v; 478 caddr_t sg; 479 long bsize, dsize, tsize, taddr, baddr, daddr; 480 struct nameidata ni; 481 struct vnode *vp; 482 struct exec hdr; 483 struct exec_vmcmd_set vcset; 484 int rem, i, magic, error; 485 486 sg = stackgap_init(p->p_emul); 487 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 488 489 NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 490 491 if ((error = namei(&ni))) 492 return error; 493 494 vp = ni.ni_vp; 495 496 if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE, 497 0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, 498 &rem, p))) { 499 vrele(vp); 500 return error; 501 } 502 503 if (rem != 0) { 504 vrele(vp); 505 return ENOEXEC; 506 } 507 508 if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE) 509 return ENOEXEC; 510 511 magic = LINUX_N_MAGIC(&hdr); 512 taddr = hdr.a_entry & (~(NBPG - 1)); 513 tsize = hdr.a_text; 514 daddr = taddr + tsize; 515 dsize = hdr.a_data + hdr.a_bss; 516 517 if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) { 518 vrele(vp); 519 return ETXTBSY; 520 } 521 vp->v_flag |= VTEXT; 522 523 vcset.evs_cnt = 0; 524 vcset.evs_used = 0; 525 526 NEW_VMCMD(&vcset, 527 magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn, 528 hdr.a_text + hdr.a_data, taddr, 529 vp, LINUX_N_TXTOFF(hdr, magic), 530 VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE); 531 532 baddr = roundup(daddr + hdr.a_data, NBPG); 533 bsize = daddr + dsize - baddr; 534 if (bsize > 0) { 535 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr, 536 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 537 } 538 539 for (i = 0; i < vcset.evs_used && !error; i++) { 540 struct exec_vmcmd *vcp; 541 542 vcp = &vcset.evs_cmds[i]; 543 error = (*vcp->ev_proc)(p, vcp); 544 } 545 546 kill_vmcmds(&vcset); 547 548 vrele(vp); 549 550 return error; 551 } 552 553 /* 554 * Execve(2). Just check the alternate emulation path, and pass it on 555 * to the NetBSD execve(). 556 */ 557 int 558 linux_sys_execve(p, v, retval) 559 struct proc *p; 560 void *v; 561 register_t *retval; 562 { 563 struct linux_sys_execve_args /* { 564 syscallarg(char *) path; 565 syscallarg(char **) argv; 566 syscallarg(char **) envp; 567 } */ *uap = v; 568 struct sys_execve_args ap; 569 caddr_t sg; 570 571 sg = stackgap_init(p->p_emul); 572 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 573 574 SCARG(&ap, path) = SCARG(uap, path); 575 SCARG(&ap, argp) = SCARG(uap, argp); 576 SCARG(&ap, envp) = SCARG(uap, envp); 577 578 return sys_execve(p, &ap, retval); 579 } 580
Indexes created Mon Sep 22 05:09:51 GMT 2025