linux_exec_elf32.c revision 1.18
1 /* $NetBSD: linux_exec_elf32.c,v 1.18 1996/09/27 18:14:25 cgd 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 #define EXEC_ELF32 /* XXX should die */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/kernel.h> 39 #include <sys/proc.h> 40 #include <sys/malloc.h> 41 #include <sys/namei.h> 42 #include <sys/vnode.h> 43 #include <sys/mount.h> 44 #include <sys/exec_elf.h> 45 46 #include <sys/mman.h> 47 #include <sys/syscallargs.h> 48 49 #include <vm/vm.h> 50 #include <vm/vm_param.h> 51 #include <vm/vm_map.h> 52 53 #include <machine/cpu.h> 54 #include <machine/reg.h> 55 #include <machine/exec.h> 56 #include <machine/linux_machdep.h> 57 58 #include <compat/linux/linux_types.h> 59 #include <compat/linux/linux_syscall.h> 60 #include <compat/linux/linux_signal.h> 61 #include <compat/linux/linux_syscallargs.h> 62 #include <compat/linux/linux_util.h> 63 #include <compat/linux/linux_exec.h> 64 65 static void *linux_aout_copyargs __P((struct exec_package *, 66 struct ps_strings *, void *, void *)); 67 static int linux_elf32_signature __P((struct proc *p, struct exec_package *, 68 Elf32_Ehdr *)); 69 70 #define LINUX_AOUT_AUX_ARGSIZ 2 71 #define LINUX_ELF_AUX_ARGSIZ (sizeof(AuxInfo) * 8 / sizeof(char *)) 72 73 74 const char linux_emul_path[] = "/emul/linux"; 75 extern int linux_error[]; 76 extern char linux_sigcode[], linux_esigcode[]; 77 extern struct sysent linux_sysent[]; 78 extern char *linux_syscallnames[]; 79 80 int exec_linux_aout_prep_zmagic __P((struct proc *, struct exec_package *)); 81 int exec_linux_aout_prep_nmagic __P((struct proc *, struct exec_package *)); 82 int exec_linux_aout_prep_omagic __P((struct proc *, struct exec_package *)); 83 int exec_linux_aout_prep_qmagic __P((struct proc *, struct exec_package *)); 84 85 struct emul emul_linux_aout = { 86 "linux", 87 linux_error, 88 linux_sendsig, 89 LINUX_SYS_syscall, 90 LINUX_SYS_MAXSYSCALL, 91 linux_sysent, 92 linux_syscallnames, 93 LINUX_AOUT_AUX_ARGSIZ, 94 linux_aout_copyargs, 95 setregs, 96 linux_sigcode, 97 linux_esigcode, 98 }; 99 100 struct emul emul_linux_elf = { 101 "linux", 102 linux_error, 103 linux_sendsig, 104 LINUX_SYS_syscall, 105 LINUX_SYS_MAXSYSCALL, 106 linux_sysent, 107 linux_syscallnames, 108 LINUX_ELF_AUX_ARGSIZ, 109 elf32_copyargs, 110 setregs, 111 linux_sigcode, 112 linux_esigcode, 113 }; 114 115 116 static void * 117 linux_aout_copyargs(pack, arginfo, stack, argp) 118 struct exec_package *pack; 119 struct ps_strings *arginfo; 120 void *stack; 121 void *argp; 122 { 123 char **cpp = stack; 124 char **stk = stack; 125 char *dp, *sp; 126 size_t len; 127 void *nullp = NULL; 128 int argc = arginfo->ps_nargvstr; 129 int envc = arginfo->ps_nenvstr; 130 131 if (copyout(&argc, cpp++, sizeof(argc))) 132 return NULL; 133 134 /* leave room for envp and argv */ 135 cpp += 2; 136 if (copyout(&cpp, &stk[1], sizeof (cpp))) 137 return NULL; 138 139 dp = (char *) (cpp + argc + envc + 2); 140 sp = argp; 141 142 /* XXX don't copy them out, remap them! */ 143 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 144 145 for (; --argc >= 0; sp += len, dp += len) 146 if (copyout(&dp, cpp++, sizeof(dp)) || 147 copyoutstr(sp, dp, ARG_MAX, &len)) 148 return NULL; 149 150 if (copyout(&nullp, cpp++, sizeof(nullp))) 151 return NULL; 152 153 if (copyout(&cpp, &stk[2], sizeof (cpp))) 154 return NULL; 155 156 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 157 158 for (; --envc >= 0; sp += len, dp += len) 159 if (copyout(&dp, cpp++, sizeof(dp)) || 160 copyoutstr(sp, dp, ARG_MAX, &len)) 161 return NULL; 162 163 if (copyout(&nullp, cpp++, sizeof(nullp))) 164 return NULL; 165 166 return cpp; 167 } 168 169 int 170 exec_linux_aout_makecmds(p, epp) 171 struct proc *p; 172 struct exec_package *epp; 173 { 174 struct exec *linux_ep = epp->ep_hdr; 175 int machtype, magic; 176 int error = ENOEXEC; 177 178 magic = LINUX_N_MAGIC(linux_ep); 179 machtype = LINUX_N_MACHTYPE(linux_ep); 180 181 182 if (machtype != LINUX_MID_MACHINE) 183 return (ENOEXEC); 184 185 switch (magic) { 186 case QMAGIC: 187 error = exec_linux_aout_prep_qmagic(p, epp); 188 break; 189 case ZMAGIC: 190 error = exec_linux_aout_prep_zmagic(p, epp); 191 break; 192 case NMAGIC: 193 error = exec_linux_aout_prep_nmagic(p, epp); 194 break; 195 case OMAGIC: 196 error = exec_linux_aout_prep_omagic(p, epp); 197 break; 198 } 199 if (error == 0) 200 epp->ep_emul = &emul_linux_aout; 201 return error; 202 } 203 204 /* 205 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400 206 * is very likely not page aligned on most architectures, it is treated 207 * as an NMAGIC here. XXX 208 */ 209 210 int 211 exec_linux_aout_prep_zmagic(p, epp) 212 struct proc *p; 213 struct exec_package *epp; 214 { 215 struct exec *execp = epp->ep_hdr; 216 217 epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC); 218 epp->ep_tsize = execp->a_text; 219 epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC); 220 epp->ep_dsize = execp->a_data + execp->a_bss; 221 epp->ep_entry = execp->a_entry; 222 223 /* set up command for text segment */ 224 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 225 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC), 226 VM_PROT_READ|VM_PROT_EXECUTE); 227 228 /* set up command for data segment */ 229 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 230 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC), 231 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 232 233 /* set up command for bss segment */ 234 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 235 epp->ep_daddr + execp->a_data, NULLVP, 0, 236 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 237 238 return exec_aout_setup_stack(p, epp); 239 } 240 241 /* 242 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package. 243 * Not different from the normal stuff. 244 */ 245 246 int 247 exec_linux_aout_prep_nmagic(p, epp) 248 struct proc *p; 249 struct exec_package *epp; 250 { 251 struct exec *execp = epp->ep_hdr; 252 long bsize, baddr; 253 254 epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC); 255 epp->ep_tsize = execp->a_text; 256 epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC); 257 epp->ep_dsize = execp->a_data + execp->a_bss; 258 epp->ep_entry = execp->a_entry; 259 260 /* set up command for text segment */ 261 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 262 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC), 263 VM_PROT_READ|VM_PROT_EXECUTE); 264 265 /* set up command for data segment */ 266 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 267 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC), 268 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 269 270 /* set up command for bss segment */ 271 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 272 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 273 if (bsize > 0) 274 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 275 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 276 277 return exec_aout_setup_stack(p, epp); 278 } 279 280 /* 281 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package. 282 * Business as usual. 283 */ 284 285 int 286 exec_linux_aout_prep_omagic(p, epp) 287 struct proc *p; 288 struct exec_package *epp; 289 { 290 struct exec *execp = epp->ep_hdr; 291 long dsize, bsize, baddr; 292 293 epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC); 294 epp->ep_tsize = execp->a_text; 295 epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC); 296 epp->ep_dsize = execp->a_data + execp->a_bss; 297 epp->ep_entry = execp->a_entry; 298 299 /* set up command for text and data segments */ 300 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 301 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 302 LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 303 304 /* set up command for bss segment */ 305 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 306 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 307 if (bsize > 0) 308 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 309 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 310 311 /* 312 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 313 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 314 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 315 * respectively to page boundaries. 316 * Compensate `ep_dsize' for the amount of data covered by the last 317 * text page. 318 */ 319 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 320 epp->ep_dsize = (dsize > 0) ? dsize : 0; 321 return exec_aout_setup_stack(p, epp); 322 } 323 324 int 325 exec_linux_aout_prep_qmagic(p, epp) 326 struct proc *p; 327 struct exec_package *epp; 328 { 329 struct exec *execp = epp->ep_hdr; 330 331 epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC); 332 epp->ep_tsize = execp->a_text; 333 epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC); 334 epp->ep_dsize = execp->a_data + execp->a_bss; 335 epp->ep_entry = execp->a_entry; 336 337 /* 338 * check if vnode is in open for writing, because we want to 339 * demand-page out of it. if it is, don't do it, for various 340 * reasons 341 */ 342 if ((execp->a_text != 0 || execp->a_data != 0) && 343 epp->ep_vp->v_writecount != 0) { 344 #ifdef DIAGNOSTIC 345 if (epp->ep_vp->v_flag & VTEXT) 346 panic("exec: a VTEXT vnode has writecount != 0\n"); 347 #endif 348 return ETXTBSY; 349 } 350 epp->ep_vp->v_flag |= VTEXT; 351 352 /* set up command for text segment */ 353 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text, 354 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC), 355 VM_PROT_READ|VM_PROT_EXECUTE); 356 357 /* set up command for data segment */ 358 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data, 359 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC), 360 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 361 362 /* set up command for bss segment */ 363 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 364 epp->ep_daddr + execp->a_data, NULLVP, 0, 365 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 366 367 return exec_aout_setup_stack(p, epp); 368 } 369 370 /* 371 * Take advantage of the fact that all the linux binaries are compiled 372 * with gcc, and gcc sticks in the comment field a signature. Note that 373 * on SVR4 binaries, the gcc signature will follow the OS name signature, 374 * that will not be a problem. We don't bother to read in the string table, 375 * but we check all the progbits headers. 376 */ 377 static int 378 linux_elf32_signature(p, epp, eh) 379 struct proc *p; 380 struct exec_package *epp; 381 Elf32_Ehdr *eh; 382 { 383 size_t shsize = sizeof(Elf32_Shdr) * eh->e_shnum; 384 size_t i; 385 static const char signature[] = "\0GCC: (GNU) "; 386 char buf[sizeof(signature) - 1]; 387 Elf32_Shdr *sh; 388 int error; 389 390 sh = (Elf32_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 391 392 if ((error = elf32_read_from(p, epp->ep_vp, eh->e_shoff, 393 (caddr_t) sh, shsize)) != 0) 394 goto out; 395 396 for (i = 0; i < eh->e_shnum; i++) { 397 Elf32_Shdr *s = &sh[i]; 398 399 /* 400 * Identify candidates for the comment header; 401 * Header cannot have a load address, or flags and 402 * it must be large enough. 403 */ 404 if (s->sh_type != Elf32_sht_progbits || 405 s->sh_addr != 0 || 406 s->sh_flags != 0 || 407 s->sh_size < sizeof(signature) - 1) 408 continue; 409 410 if ((error = elf32_read_from(p, epp->ep_vp, s->sh_offset, 411 (caddr_t) buf, sizeof(signature) - 1)) != 0) 412 goto out; 413 414 /* 415 * error is 0, if the signatures match we are done. 416 */ 417 if (bcmp(buf, signature, sizeof(signature) - 1) == 0) 418 goto out; 419 } 420 error = EFTYPE; 421 422 out: 423 free(sh, M_TEMP); 424 return error; 425 } 426 427 int 428 linux_elf32_probe(p, epp, eh, itp, pos) 429 struct proc *p; 430 struct exec_package *epp; 431 Elf32_Ehdr *eh; 432 char *itp; 433 Elf32_Addr *pos; 434 { 435 char *bp; 436 int error; 437 size_t len; 438 439 if ((error = linux_elf32_signature(p, epp, eh)) != 0) 440 return error; 441 442 if (itp[0]) { 443 if ((error = emul_find(p, NULL, linux_emul_path, itp, &bp, 0))) 444 return error; 445 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 446 return error; 447 free(bp, M_TEMP); 448 } 449 epp->ep_emul = &emul_linux_elf; 450 *pos = ELF32_NO_ADDR; 451 return 0; 452 } 453 454 /* 455 * The Linux system call to load shared libraries, a.out version. The 456 * a.out shared libs are just files that are mapped onto a fixed 457 * address in the process' address space. The address is given in 458 * a_entry. Read in the header, set up some VM commands and run them. 459 * 460 * Yes, both text and data are mapped at once, so we're left with 461 * writeable text for the shared libs. The Linux crt0 seemed to break 462 * sometimes when data was mapped seperately. It munmapped a uselib() 463 * of ld.so by hand, which failed with shared text and data for ld.so 464 * Yuck. 465 * 466 * Because of the problem with ZMAGIC executables (text starts 467 * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC 468 * shared libs are not handled very efficiently :-( 469 */ 470 471 int 472 linux_sys_uselib(p, v, retval) 473 struct proc *p; 474 void *v; 475 register_t *retval; 476 { 477 struct linux_sys_uselib_args /* { 478 syscallarg(char *) path; 479 } */ *uap = v; 480 caddr_t sg; 481 long bsize, dsize, tsize, taddr, baddr, daddr; 482 struct nameidata ni; 483 struct vnode *vp; 484 struct exec hdr; 485 struct exec_vmcmd_set vcset; 486 int rem, i, magic, error; 487 488 sg = stackgap_init(p->p_emul); 489 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 490 491 NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 492 493 if ((error = namei(&ni))) 494 return error; 495 496 vp = ni.ni_vp; 497 498 if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE, 499 0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, 500 &rem, p))) { 501 vrele(vp); 502 return error; 503 } 504 505 if (rem != 0) { 506 vrele(vp); 507 return ENOEXEC; 508 } 509 510 if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE) 511 return ENOEXEC; 512 513 magic = LINUX_N_MAGIC(&hdr); 514 taddr = hdr.a_entry & (~(NBPG - 1)); 515 tsize = hdr.a_text; 516 daddr = taddr + tsize; 517 dsize = hdr.a_data + hdr.a_bss; 518 519 if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) { 520 vrele(vp); 521 return ETXTBSY; 522 } 523 vp->v_flag |= VTEXT; 524 525 vcset.evs_cnt = 0; 526 vcset.evs_used = 0; 527 528 NEW_VMCMD(&vcset, 529 magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn, 530 hdr.a_text + hdr.a_data, taddr, 531 vp, LINUX_N_TXTOFF(hdr, magic), 532 VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE); 533 534 baddr = roundup(daddr + hdr.a_data, NBPG); 535 bsize = daddr + dsize - baddr; 536 if (bsize > 0) { 537 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr, 538 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 539 } 540 541 for (i = 0; i < vcset.evs_used && !error; i++) { 542 struct exec_vmcmd *vcp; 543 544 vcp = &vcset.evs_cmds[i]; 545 error = (*vcp->ev_proc)(p, vcp); 546 } 547 548 kill_vmcmds(&vcset); 549 550 vrele(vp); 551 552 return error; 553 } 554 555 /* 556 * Execve(2). Just check the alternate emulation path, and pass it on 557 * to the NetBSD execve(). 558 */ 559 int 560 linux_sys_execve(p, v, retval) 561 struct proc *p; 562 void *v; 563 register_t *retval; 564 { 565 struct linux_sys_execve_args /* { 566 syscallarg(char *) path; 567 syscallarg(char **) argv; 568 syscallarg(char **) envp; 569 } */ *uap = v; 570 struct sys_execve_args ap; 571 caddr_t sg; 572 573 sg = stackgap_init(p->p_emul); 574 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 575 576 SCARG(&ap, path) = SCARG(uap, path); 577 SCARG(&ap, argp) = SCARG(uap, argp); 578 SCARG(&ap, envp) = SCARG(uap, envp); 579 580 return sys_execve(p, &ap, retval); 581 } 582
Indexes created Mon Sep 22 05:09:51 GMT 2025