1 /* $NetBSD: linux_exec.c,v 1.25 1996/10/13 18:30:05 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.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/linux_machdep.h> 56 57 #include <compat/linux/linux_types.h> 58 #include <compat/linux/linux_syscall.h> 59 #include <compat/linux/linux_signal.h> 60 #include <compat/linux/linux_syscallargs.h> 61 #include <compat/linux/linux_util.h> 62 #include <compat/linux/linux_exec.h> 63 64 static void *linux_aout_copyargs __P((struct exec_package *, 65 struct ps_strings *, void *, void *)); 66 static int linux_elf32_signature __P((struct proc *p, struct exec_package *, 67 Elf32_Ehdr *)); 68 69 #define LINUX_AOUT_AUX_ARGSIZ 2 70 #define LINUX_ELF_AUX_ARGSIZ (sizeof(AuxInfo) * 8 / sizeof(char *)) 71 72 73 const char linux_emul_path[] = "/emul/linux"; 74 extern int linux_error[]; 75 extern char linux_sigcode[], linux_esigcode[]; 76 extern struct sysent linux_sysent[]; 77 extern char *linux_syscallnames[]; 78 79 int exec_linux_aout_prep_zmagic __P((struct proc *, struct exec_package *)); 80 int exec_linux_aout_prep_nmagic __P((struct proc *, struct exec_package *)); 81 int exec_linux_aout_prep_omagic __P((struct proc *, struct exec_package *)); 82 int exec_linux_aout_prep_qmagic __P((struct proc *, struct exec_package *)); 83 84 struct emul emul_linux_aout = { 85 "linux", 86 linux_error, 87 linux_sendsig, 88 LINUX_SYS_syscall, 89 LINUX_SYS_MAXSYSCALL, 90 linux_sysent, 91 linux_syscallnames, 92 LINUX_AOUT_AUX_ARGSIZ, 93 linux_aout_copyargs, 94 setregs, 95 linux_sigcode, 96 linux_esigcode, 97 }; 98 99 struct emul emul_linux_elf = { 100 "linux", 101 linux_error, 102 linux_sendsig, 103 LINUX_SYS_syscall, 104 LINUX_SYS_MAXSYSCALL, 105 linux_sysent, 106 linux_syscallnames, 107 LINUX_ELF_AUX_ARGSIZ, 108 elf32_copyargs, 109 setregs, 110 linux_sigcode, 111 linux_esigcode, 112 }; 113 114 115 static void * 116 linux_aout_copyargs(pack, arginfo, stack, argp) 117 struct exec_package *pack; 118 struct ps_strings *arginfo; 119 void *stack; 120 void *argp; 121 { 122 char **cpp = stack; 123 char **stk = stack; 124 char *dp, *sp; 125 size_t len; 126 void *nullp = NULL; 127 int argc = arginfo->ps_nargvstr; 128 int envc = arginfo->ps_nenvstr; 129 130 if (copyout(&argc, cpp++, sizeof(argc))) 131 return NULL; 132 133 /* leave room for envp and argv */ 134 cpp += 2; 135 if (copyout(&cpp, &stk[1], sizeof (cpp))) 136 return NULL; 137 138 dp = (char *) (cpp + argc + envc + 2); 139 sp = argp; 140 141 /* XXX don't copy them out, remap them! */ 142 arginfo->ps_argvstr = cpp; /* remember location of argv for later */ 143 144 for (; --argc >= 0; sp += len, dp += len) 145 if (copyout(&dp, cpp++, sizeof(dp)) || 146 copyoutstr(sp, dp, ARG_MAX, &len)) 147 return NULL; 148 149 if (copyout(&nullp, cpp++, sizeof(nullp))) 150 return NULL; 151 152 if (copyout(&cpp, &stk[2], sizeof (cpp))) 153 return NULL; 154 155 arginfo->ps_envstr = cpp; /* remember location of envp for later */ 156 157 for (; --envc >= 0; sp += len, dp += len) 158 if (copyout(&dp, cpp++, sizeof(dp)) || 159 copyoutstr(sp, dp, ARG_MAX, &len)) 160 return NULL; 161 162 if (copyout(&nullp, cpp++, sizeof(nullp))) 163 return NULL; 164 165 return cpp; 166 } 167 168 int 169 exec_linux_aout_makecmds(p, epp) 170 struct proc *p; 171 struct exec_package *epp; 172 { 173 struct exec *linux_ep = epp->ep_hdr; 174 int machtype, magic; 175 int error = ENOEXEC; 176 177 magic = LINUX_N_MAGIC(linux_ep); 178 machtype = LINUX_N_MACHTYPE(linux_ep); 179 180 181 if (machtype != LINUX_MID_MACHINE) 182 return (ENOEXEC); 183 184 switch (magic) { 185 case QMAGIC: 186 error = exec_linux_aout_prep_qmagic(p, epp); 187 break; 188 case ZMAGIC: 189 error = exec_linux_aout_prep_zmagic(p, epp); 190 break; 191 case NMAGIC: 192 error = exec_linux_aout_prep_nmagic(p, epp); 193 break; 194 case OMAGIC: 195 error = exec_linux_aout_prep_omagic(p, epp); 196 break; 197 } 198 if (error == 0) 199 epp->ep_emul = &emul_linux_aout; 200 return error; 201 } 202 203 /* 204 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400 205 * is very likely not page aligned on most architectures, it is treated 206 * as an NMAGIC here. XXX 207 */ 208 209 int 210 exec_linux_aout_prep_zmagic(p, epp) 211 struct proc *p; 212 struct exec_package *epp; 213 { 214 struct exec *execp = epp->ep_hdr; 215 216 epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC); 217 epp->ep_tsize = execp->a_text; 218 epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC); 219 epp->ep_dsize = execp->a_data + execp->a_bss; 220 epp->ep_entry = execp->a_entry; 221 222 /* set up command for text segment */ 223 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 224 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC), 225 VM_PROT_READ|VM_PROT_EXECUTE); 226 227 /* set up command for data segment */ 228 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 229 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC), 230 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 231 232 /* set up command for bss segment */ 233 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 234 epp->ep_daddr + execp->a_data, NULLVP, 0, 235 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 236 237 return exec_aout_setup_stack(p, epp); 238 } 239 240 /* 241 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package. 242 * Not different from the normal stuff. 243 */ 244 245 int 246 exec_linux_aout_prep_nmagic(p, epp) 247 struct proc *p; 248 struct exec_package *epp; 249 { 250 struct exec *execp = epp->ep_hdr; 251 long bsize, baddr; 252 253 epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC); 254 epp->ep_tsize = execp->a_text; 255 epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC); 256 epp->ep_dsize = execp->a_data + execp->a_bss; 257 epp->ep_entry = execp->a_entry; 258 259 /* set up command for text segment */ 260 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 261 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC), 262 VM_PROT_READ|VM_PROT_EXECUTE); 263 264 /* set up command for data segment */ 265 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 266 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC), 267 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 268 269 /* set up command for bss segment */ 270 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 271 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 272 if (bsize > 0) 273 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 274 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 275 276 return exec_aout_setup_stack(p, epp); 277 } 278 279 /* 280 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package. 281 * Business as usual. 282 */ 283 284 int 285 exec_linux_aout_prep_omagic(p, epp) 286 struct proc *p; 287 struct exec_package *epp; 288 { 289 struct exec *execp = epp->ep_hdr; 290 long dsize, bsize, baddr; 291 292 epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC); 293 epp->ep_tsize = execp->a_text; 294 epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC); 295 epp->ep_dsize = execp->a_data + execp->a_bss; 296 epp->ep_entry = execp->a_entry; 297 298 /* set up command for text and data segments */ 299 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 300 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 301 LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 302 303 /* set up command for bss segment */ 304 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 305 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 306 if (bsize > 0) 307 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 308 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 309 310 /* 311 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 312 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 313 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 314 * respectively to page boundaries. 315 * Compensate `ep_dsize' for the amount of data covered by the last 316 * text page. 317 */ 318 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 319 epp->ep_dsize = (dsize > 0) ? dsize : 0; 320 return exec_aout_setup_stack(p, epp); 321 } 322 323 int 324 exec_linux_aout_prep_qmagic(p, epp) 325 struct proc *p; 326 struct exec_package *epp; 327 { 328 struct exec *execp = epp->ep_hdr; 329 330 epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC); 331 epp->ep_tsize = execp->a_text; 332 epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC); 333 epp->ep_dsize = execp->a_data + execp->a_bss; 334 epp->ep_entry = execp->a_entry; 335 336 /* 337 * check if vnode is in open for writing, because we want to 338 * demand-page out of it. if it is, don't do it, for various 339 * reasons 340 */ 341 if ((execp->a_text != 0 || execp->a_data != 0) && 342 epp->ep_vp->v_writecount != 0) { 343 #ifdef DIAGNOSTIC 344 if (epp->ep_vp->v_flag & VTEXT) 345 panic("exec: a VTEXT vnode has writecount != 0\n"); 346 #endif 347 return ETXTBSY; 348 } 349 epp->ep_vp->v_flag |= VTEXT; 350 351 /* set up command for text segment */ 352 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text, 353 epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC), 354 VM_PROT_READ|VM_PROT_EXECUTE); 355 356 /* set up command for data segment */ 357 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data, 358 epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC), 359 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 360 361 /* set up command for bss segment */ 362 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 363 epp->ep_daddr + execp->a_data, NULLVP, 0, 364 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 365 366 return exec_aout_setup_stack(p, epp); 367 } 368 369 /* 370 * Take advantage of the fact that all the linux binaries are compiled 371 * with gcc, and gcc sticks in the comment field a signature. Note that 372 * on SVR4 binaries, the gcc signature will follow the OS name signature, 373 * that will not be a problem. We don't bother to read in the string table, 374 * but we check all the progbits headers. 375 */ 376 static int 377 linux_elf32_signature(p, epp, eh) 378 struct proc *p; 379 struct exec_package *epp; 380 Elf32_Ehdr *eh; 381 { 382 size_t shsize = sizeof(Elf32_Shdr) * eh->e_shnum; 383 size_t i; 384 static const char signature[] = "\0GCC: (GNU) "; 385 char buf[sizeof(signature) - 1]; 386 Elf32_Shdr *sh; 387 int error; 388 389 sh = (Elf32_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 390 391 if ((error = elf32_read_from(p, epp->ep_vp, eh->e_shoff, 392 (caddr_t) sh, shsize)) != 0) 393 goto out; 394 395 for (i = 0; i < eh->e_shnum; i++) { 396 Elf32_Shdr *s = &sh[i]; 397 398 /* 399 * Identify candidates for the comment header; 400 * Header cannot have a load address, or flags and 401 * it must be large enough. 402 */ 403 if (s->sh_type != Elf_sht_progbits || 404 s->sh_addr != 0 || 405 s->sh_flags != 0 || 406 s->sh_size < sizeof(signature) - 1) 407 continue; 408 409 if ((error = elf32_read_from(p, epp->ep_vp, s->sh_offset, 410 (caddr_t) buf, sizeof(signature) - 1)) != 0) 411 goto out; 412 413 /* 414 * error is 0, if the signatures match we are done. 415 */ 416 if (bcmp(buf, signature, sizeof(signature) - 1) == 0) 417 goto out; 418 } 419 error = EFTYPE; 420 421 out: 422 free(sh, M_TEMP); 423 return error; 424 } 425 426 int 427 linux_elf32_probe(p, epp, eh, itp, pos) 428 struct proc *p; 429 struct exec_package *epp; 430 Elf32_Ehdr *eh; 431 char *itp; 432 Elf32_Addr *pos; 433 { 434 char *bp; 435 int error; 436 size_t len; 437 438 if ((error = linux_elf32_signature(p, epp, eh)) != 0) 439 return error; 440 441 if (itp[0]) { 442 if ((error = emul_find(p, NULL, linux_emul_path, itp, &bp, 0))) 443 return error; 444 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 445 return error; 446 free(bp, M_TEMP); 447 } 448 epp->ep_emul = &emul_linux_elf; 449 *pos = ELF32_NO_ADDR; 450 return 0; 451 } 452 453 /* 454 * The Linux system call to load shared libraries, a.out version. The 455 * a.out shared libs are just files that are mapped onto a fixed 456 * address in the process' address space. The address is given in 457 * a_entry. Read in the header, set up some VM commands and run them. 458 * 459 * Yes, both text and data are mapped at once, so we're left with 460 * writeable text for the shared libs. The Linux crt0 seemed to break 461 * sometimes when data was mapped seperately. It munmapped a uselib() 462 * of ld.so by hand, which failed with shared text and data for ld.so 463 * Yuck. 464 * 465 * Because of the problem with ZMAGIC executables (text starts 466 * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC 467 * shared libs are not handled very efficiently :-( 468 */ 469 470 int 471 linux_sys_uselib(p, v, retval) 472 struct proc *p; 473 void *v; 474 register_t *retval; 475 { 476 struct linux_sys_uselib_args /* { 477 syscallarg(char *) path; 478 } */ *uap = v; 479 caddr_t sg; 480 long bsize, dsize, tsize, taddr, baddr, daddr; 481 struct nameidata ni; 482 struct vnode *vp; 483 struct exec hdr; 484 struct exec_vmcmd_set vcset; 485 int rem, i, magic, error; 486 487 sg = stackgap_init(p->p_emul); 488 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 489 490 NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p); 491 492 if ((error = namei(&ni))) 493 return error; 494 495 vp = ni.ni_vp; 496 497 if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE, 498 0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, 499 &rem, p))) { 500 vrele(vp); 501 return error; 502 } 503 504 if (rem != 0) { 505 vrele(vp); 506 return ENOEXEC; 507 } 508 509 if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE) 510 return ENOEXEC; 511 512 magic = LINUX_N_MAGIC(&hdr); 513 taddr = hdr.a_entry & (~(NBPG - 1)); 514 tsize = hdr.a_text; 515 daddr = taddr + tsize; 516 dsize = hdr.a_data + hdr.a_bss; 517 518 if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) { 519 vrele(vp); 520 return ETXTBSY; 521 } 522 vp->v_flag |= VTEXT; 523 524 vcset.evs_cnt = 0; 525 vcset.evs_used = 0; 526 527 NEW_VMCMD(&vcset, 528 magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn, 529 hdr.a_text + hdr.a_data, taddr, 530 vp, LINUX_N_TXTOFF(hdr, magic), 531 VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE); 532 533 baddr = roundup(daddr + hdr.a_data, NBPG); 534 bsize = daddr + dsize - baddr; 535 if (bsize > 0) { 536 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr, 537 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 538 } 539 540 for (i = 0; i < vcset.evs_used && !error; i++) { 541 struct exec_vmcmd *vcp; 542 543 vcp = &vcset.evs_cmds[i]; 544 error = (*vcp->ev_proc)(p, vcp); 545 } 546 547 kill_vmcmds(&vcset); 548 549 vrele(vp); 550 551 return error; 552 } 553 554 /* 555 * Execve(2). Just check the alternate emulation path, and pass it on 556 * to the NetBSD execve(). 557 */ 558 int 559 linux_sys_execve(p, v, retval) 560 struct proc *p; 561 void *v; 562 register_t *retval; 563 { 564 struct linux_sys_execve_args /* { 565 syscallarg(char *) path; 566 syscallarg(char **) argv; 567 syscallarg(char **) envp; 568 } */ *uap = v; 569 struct sys_execve_args ap; 570 caddr_t sg; 571 572 sg = stackgap_init(p->p_emul); 573 LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path)); 574 575 SCARG(&ap, path) = SCARG(uap, path); 576 SCARG(&ap, argp) = SCARG(uap, argp); 577 SCARG(&ap, envp) = SCARG(uap, envp); 578 579 return sys_execve(p, &ap, retval); 580 } 581