linux_exec_elf32.c revision 1.16
1 /* $NetBSD: linux_exec_elf32.c,v 1.16 1996/09/03 03:12:28 mycroft 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 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/proc.h> 37 #include <sys/malloc.h> 38 #include <sys/namei.h> 39 #include <sys/vnode.h> 40 #include <sys/mount.h> 41 #include <sys/exec_elf.h> 42 43 #include <sys/mman.h> 44 #include <sys/syscallargs.h> 45 46 #include <vm/vm.h> 47 #include <vm/vm_param.h> 48 #include <vm/vm_map.h> 49 50 #include <machine/cpu.h> 51 #include <machine/reg.h> 52 #include <machine/exec.h> 53 #include <machine/linux_machdep.h> 54 55 #include <compat/linux/linux_types.h> 56 #include <compat/linux/linux_syscall.h> 57 #include <compat/linux/linux_signal.h> 58 #include <compat/linux/linux_syscallargs.h> 59 #include <compat/linux/linux_util.h> 60 #include <compat/linux/linux_exec.h> 61 62 static void *linux_aout_copyargs __P((struct exec_package *, 63 struct ps_strings *, void *, void *)); 64 static int linux_elf_signature __P((struct proc *p, struct exec_package *, 65 Elf32_Ehdr *)); 66 67 #define LINUX_AOUT_AUX_ARGSIZ 2 68 #define LINUX_ELF_AUX_ARGSIZ (sizeof(AuxInfo) * 8 / sizeof(char *)) 69 70 71 const char linux_emul_path[] = "/emul/linux"; 72 extern int linux_error[]; 73 extern char linux_sigcode[], linux_esigcode[]; 74 extern struct sysent linux_sysent[]; 75 extern char *linux_syscallnames[]; 76 77 int exec_linux_aout_prep_zmagic __P((struct proc *, struct exec_package *)); 78 int exec_linux_aout_prep_nmagic __P((struct proc *, struct exec_package *)); 79 int exec_linux_aout_prep_omagic __P((struct proc *, struct exec_package *)); 80 int exec_linux_aout_prep_qmagic __P((struct proc *, struct exec_package *)); 81 82 struct emul emul_linux_aout = { 83 "linux", 84 linux_error, 85 linux_sendsig, 86 LINUX_SYS_syscall, 87 LINUX_SYS_MAXSYSCALL, 88 linux_sysent, 89 linux_syscallnames, 90 LINUX_AOUT_AUX_ARGSIZ, 91 linux_aout_copyargs, 92 setregs, 93 linux_sigcode, 94 linux_esigcode, 95 }; 96 97 struct emul emul_linux_elf = { 98 "linux", 99 linux_error, 100 linux_sendsig, 101 LINUX_SYS_syscall, 102 LINUX_SYS_MAXSYSCALL, 103 linux_sysent, 104 linux_syscallnames, 105 LINUX_ELF_AUX_ARGSIZ, 106 elf_copyargs, 107 setregs, 108 linux_sigcode, 109 linux_esigcode, 110 }; 111 112 113 static void * 114 linux_aout_copyargs(pack, arginfo, stack, argp) 115 struct exec_package *pack; 116 struct ps_strings *arginfo; 117 void *stack; 118 void *argp; 119 { 120 char **cpp = stack; 121 char **stk = stack; 122 char *dp, *sp; 123 size_t len; 124 void *nullp = NULL; 125 int argc = arginfo->ps_nargvstr; 126 int envc = arginfo->ps_nenvstr; 127 128 if (copyout(&argc, cpp++, sizeof(argc))) 129 return NULL; 130 131 /* leave room for envp and argv */ 132 cpp += 2; 133 if (copyout(&cpp, &stk[1], sizeof (cpp))) 134 return NULL; 135 136 dp = (char *) (cpp + argc + envc + 2); 137 sp = argp; 138 139 /* XXX don't copy them out, remap them! */ 140 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 141 142 for (; --argc >= 0; sp += len, dp += len) 143 if (copyout(&dp, cpp++, sizeof(dp)) || 144 copyoutstr(sp, dp, ARG_MAX, &len)) 145 return NULL; 146 147 if (copyout(&nullp, cpp++, sizeof(nullp))) 148 return NULL; 149 150 if (copyout(&cpp, &stk[2], sizeof (cpp))) 151 return NULL; 152 153 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 154 155 for (; --envc >= 0; sp += len, dp += len) 156 if (copyout(&dp, cpp++, sizeof(dp)) || 157 copyoutstr(sp, dp, ARG_MAX, &len)) 158 return NULL; 159 160 if (copyout(&nullp, cpp++, sizeof(nullp))) 161 return NULL; 162 163 return cpp; 164 } 165 166 int 167 exec_linux_aout_makecmds(p, epp) 168 struct proc *p; 169 struct exec_package *epp; 170 { 171 struct exec *linux_ep = epp->ep_hdr; 172 int machtype, magic; 173 int error = ENOEXEC; 174 175 magic = LINUX_N_MAGIC(linux_ep); 176 machtype = LINUX_N_MACHTYPE(linux_ep); 177 178 179 if (machtype != LINUX_MID_MACHINE) 180 return (ENOEXEC); 181 182 switch (magic) { 183 case QMAGIC: 184 error = exec_linux_aout_prep_qmagic(p, epp); 185 break; 186 case ZMAGIC: 187 error = exec_linux_aout_prep_zmagic(p, epp); 188 break; 189 case NMAGIC: 190 error = exec_linux_aout_prep_nmagic(p, epp); 191 break; 192 case OMAGIC: 193 error = exec_linux_aout_prep_omagic(p, epp); 194 break; 195 } 196 if (error == 0) 197 epp->ep_emul = &emul_linux_aout; 198 return error; 199 } 200 201 /* 202 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400 203 * is very likely not page aligned on most architectures, it is treated 204 * as an NMAGIC here. XXX 205 */ 206 207 int 208 exec_linux_aout_prep_zmagic(p, epp) 209 struct proc *p; 210 struct exec_package *epp; 211 { 212 struct exec *execp = epp->ep_hdr; 213 214 epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC); 215 epp->ep_tsize = execp->a_text; 216 epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC); 217 epp->ep_dsize = execp->a_data + execp->a_bss; 218 epp->ep_entry = execp->a_entry; 219 220 /* set up command for text segment */ 221 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 222 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC), 223 VM_PROT_READ|VM_PROT_EXECUTE); 224 225 /* set up command for data segment */ 226 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 227 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC), 228 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 229 230 /* set up command for bss segment */ 231 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 232 epp->ep_daddr + execp->a_data, NULLVP, 0, 233 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 234 235 return exec_aout_setup_stack(p, epp); 236 } 237 238 /* 239 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package. 240 * Not different from the normal stuff. 241 */ 242 243 int 244 exec_linux_aout_prep_nmagic(p, epp) 245 struct proc *p; 246 struct exec_package *epp; 247 { 248 struct exec *execp = epp->ep_hdr; 249 long bsize, baddr; 250 251 epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC); 252 epp->ep_tsize = execp->a_text; 253 epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC); 254 epp->ep_dsize = execp->a_data + execp->a_bss; 255 epp->ep_entry = execp->a_entry; 256 257 /* set up command for text segment */ 258 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 259 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC), 260 VM_PROT_READ|VM_PROT_EXECUTE); 261 262 /* set up command for data segment */ 263 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 264 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC), 265 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 266 267 /* set up command for bss segment */ 268 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 269 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 270 if (bsize > 0) 271 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 272 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 273 274 return exec_aout_setup_stack(p, epp); 275 } 276 277 /* 278 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package. 279 * Business as usual. 280 */ 281 282 int 283 exec_linux_aout_prep_omagic(p, epp) 284 struct proc *p; 285 struct exec_package *epp; 286 { 287 struct exec *execp = epp->ep_hdr; 288 long dsize, bsize, baddr; 289 290 epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC); 291 epp->ep_tsize = execp->a_text; 292 epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC); 293 epp->ep_dsize = execp->a_data + execp->a_bss; 294 epp->ep_entry = execp->a_entry; 295 296 /* set up command for text and data segments */ 297 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 298 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 299 LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 300 301 /* set up command for bss segment */ 302 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 303 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 304 if (bsize > 0) 305 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 306 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 307 308 /* 309 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 310 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 311 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 312 * respectively to page boundaries. 313 * Compensate `ep_dsize' for the amount of data covered by the last 314 * text page. 315 */ 316 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 317 epp->ep_dsize = (dsize > 0) ? dsize : 0; 318 return exec_aout_setup_stack(p, epp); 319 } 320 321 int 322 exec_linux_aout_prep_qmagic(p, epp) 323 struct proc *p; 324 struct exec_package *epp; 325 { 326 struct exec *execp = epp->ep_hdr; 327 328 epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC); 329 epp->ep_tsize = execp->a_text; 330 epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC); 331 epp->ep_dsize = execp->a_data + execp->a_bss; 332 epp->ep_entry = execp->a_entry; 333 334 /* 335 * check if vnode is in open for writing, because we want to 336 * demand-page out of it. if it is, don't do it, for various 337 * reasons 338 */ 339 if ((execp->a_text != 0 || execp->a_data != 0) && 340 epp->ep_vp->v_writecount != 0) { 341 #ifdef DIAGNOSTIC 342 if (epp->ep_vp->v_flag & VTEXT) 343 panic("exec: a VTEXT vnode has writecount != 0\n"); 344 #endif 345 return ETXTBSY; 346 } 347 epp->ep_vp->v_flag |= VTEXT; 348 349 /* set up command for text segment */ 350 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text, 351 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC), 352 VM_PROT_READ|VM_PROT_EXECUTE); 353 354 /* set up command for data segment */ 355 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data, 356 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC), 357 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 358 359 /* set up command for bss segment */ 360 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 361 epp->ep_daddr + execp->a_data, NULLVP, 0, 362 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 363 364 return exec_aout_setup_stack(p, epp); 365 } 366 367 /* 368 * Take advantage of the fact that all the linux binaries are compiled 369 * with gcc, and gcc sticks in the comment field a signature. Note that 370 * on SVR4 binaries, the gcc signature will follow the OS name signature, 371 * that will not be a problem. We don't bother to read in the string table, 372 * but we check all the progbits headers. 373 */ 374 static int 375 linux_elf_signature(p, epp, eh) 376 struct proc *p; 377 struct exec_package *epp; 378 Elf32_Ehdr *eh; 379 { 380 size_t shsize = sizeof(Elf32_Shdr) * eh->e_shnum; 381 size_t i; 382 static const char signature[] = "\0GCC: (GNU) "; 383 char buf[sizeof(signature) - 1]; 384 Elf32_Shdr *sh; 385 int error; 386 387 sh = (Elf32_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 388 389 if ((error = elf_read_from(p, epp->ep_vp, eh->e_shoff, 390 (caddr_t) sh, shsize)) != 0) 391 goto out; 392 393 for (i = 0; i < eh->e_shnum; i++) { 394 Elf32_Shdr *s = &sh[i]; 395 396 /* 397 * Identify candidates for the comment header; 398 * Header cannot have a load address, or flags and 399 * it must be large enough. 400 */ 401 if (s->sh_type != Elf32_sht_progbits || 402 s->sh_addr != 0 || 403 s->sh_flags != 0 || 404 s->sh_size < sizeof(signature) - 1) 405 continue; 406 407 if ((error = elf_read_from(p, epp->ep_vp, s->sh_offset, 408 (caddr_t) buf, sizeof(signature) - 1)) != 0) 409 goto out; 410 411 /* 412 * error is 0, if the signatures match we are done. 413 */ 414 if (bcmp(buf, signature, sizeof(signature) - 1) == 0) 415 goto out; 416 } 417 error = EFTYPE; 418 419 out: 420 free(sh, M_TEMP); 421 return error; 422 } 423 424 int 425 linux_elf_probe(p, epp, eh, itp, pos) 426 struct proc *p; 427 struct exec_package *epp; 428 Elf32_Ehdr *eh; 429 char *itp; 430 u_long *pos; 431 { 432 char *bp; 433 int error; 434 size_t len; 435 436 if ((error = linux_elf_signature(p, epp, eh)) != 0) 437 return error; 438 439 if (itp[0]) { 440 if ((error = emul_find(p, NULL, linux_emul_path, itp, &bp, 0))) 441 return error; 442 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 443 return error; 444 free(bp, M_TEMP); 445 } 446 epp->ep_emul = &emul_linux_elf; 447 *pos = ELF32_NO_ADDR; 448 return 0; 449 } 450 451 /* 452 * The Linux system call to load shared libraries, a.out version. The 453 * a.out shared libs are just files that are mapped onto a fixed 454 * address in the process' address space. The address is given in 455 * a_entry. Read in the header, set up some VM commands and run them. 456 * 457 * Yes, both text and data are mapped at once, so we're left with 458 * writeable text for the shared libs. The Linux crt0 seemed to break 459 * sometimes when data was mapped seperately. It munmapped a uselib() 460 * of ld.so by hand, which failed with shared text and data for ld.so 461 * Yuck. 462 * 463 * Because of the problem with ZMAGIC executables (text starts 464 * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC 465 * shared libs are not handled very efficiently :-( 466 */ 467 468 int 469 linux_sys_uselib(p, v, retval) 470 struct proc *p; 471 void *v; 472 register_t *retval; 473 { 474 struct linux_sys_uselib_args /* { 475 syscallarg(char *) path; 476 } */ *uap = v; 477 caddr_t sg; 478 long bsize, dsize, tsize, taddr, baddr, daddr; 479 struct nameidata ni; 480 struct vnode *vp; 481 struct exec hdr; 482 struct exec_vmcmd_set vcset; 483 int rem, i, magic, error; 484 485 sg = stackgap_init(p->p_emul); 486 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 487 488 NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 489 490 if ((error = namei(&ni))) 491 return error; 492 493 vp = ni.ni_vp; 494 495 if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE, 496 0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, 497 &rem, p))) { 498 vrele(vp); 499 return error; 500 } 501 502 if (rem != 0) { 503 vrele(vp); 504 return ENOEXEC; 505 } 506 507 if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE) 508 return ENOEXEC; 509 510 magic = LINUX_N_MAGIC(&hdr); 511 taddr = hdr.a_entry & (~(NBPG - 1)); 512 tsize = hdr.a_text; 513 daddr = taddr + tsize; 514 dsize = hdr.a_data + hdr.a_bss; 515 516 if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) { 517 vrele(vp); 518 return ETXTBSY; 519 } 520 vp->v_flag |= VTEXT; 521 522 vcset.evs_cnt = 0; 523 vcset.evs_used = 0; 524 525 NEW_VMCMD(&vcset, 526 magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn, 527 hdr.a_text + hdr.a_data, taddr, 528 vp, LINUX_N_TXTOFF(hdr, magic), 529 VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE); 530 531 baddr = roundup(daddr + hdr.a_data, NBPG); 532 bsize = daddr + dsize - baddr; 533 if (bsize > 0) { 534 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr, 535 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 536 } 537 538 for (i = 0; i < vcset.evs_used && !error; i++) { 539 struct exec_vmcmd *vcp; 540 541 vcp = &vcset.evs_cmds[i]; 542 error = (*vcp->ev_proc)(p, vcp); 543 } 544 545 kill_vmcmds(&vcset); 546 547 vrele(vp); 548 549 return error; 550 } 551 552 /* 553 * Execve(2). Just check the alternate emulation path, and pass it on 554 * to the NetBSD execve(). 555 */ 556 int 557 linux_sys_execve(p, v, retval) 558 struct proc *p; 559 void *v; 560 register_t *retval; 561 { 562 struct linux_sys_execve_args /* { 563 syscallarg(char *) path; 564 syscallarg(char **) argv; 565 syscallarg(char **) envp; 566 } */ *uap = v; 567 struct sys_execve_args ap; 568 caddr_t sg; 569 570 sg = stackgap_init(p->p_emul); 571 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 572 573 SCARG(&ap, path) = SCARG(uap, path); 574 SCARG(&ap, argp) = SCARG(uap, argp); 575 SCARG(&ap, envp) = SCARG(uap, envp); 576 577 return sys_execve(p, &ap, retval); 578 } 579
Indexes created Mon Sep 22 05:09:51 GMT 2025