Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/i386/linux/linux_sysvec.c
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1 /*- 2 * Copyright (c) 1994-1996 Søren Schmidt 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/exec.h> 35 #include <sys/imgact.h> 36 #include <sys/imgact_aout.h> 37 #include <sys/imgact_elf.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/module.h> 42 #include <sys/mutex.h> 43 #include <sys/proc.h> 44 #include <sys/signalvar.h> 45 #include <sys/syscallsubr.h> 46 #include <sys/sysent.h> 47 #include <sys/sysproto.h> 48 #include <sys/vnode.h> 49 #include <sys/eventhandler.h> 50 51 #include <vm/vm.h> 52 #include <vm/pmap.h> 53 #include <vm/vm_extern.h> 54 #include <vm/vm_map.h> 55 #include <vm/vm_object.h> 56 #include <vm/vm_page.h> 57 #include <vm/vm_param.h> 58 59 #include <machine/cpu.h> 60 #include <machine/md_var.h> 61 #include <machine/pcb.h> 62 63 #include <i386/linux/linux.h> 64 #include <i386/linux/linux_proto.h> 65 #include <compat/linux/linux_emul.h> 66 #include <compat/linux/linux_mib.h> 67 #include <compat/linux/linux_signal.h> 68 #include <compat/linux/linux_util.h> 69 70 MODULE_VERSION(linux, 1); 71 72 MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures"); 73 74 #if BYTE_ORDER == LITTLE_ENDIAN 75 #define SHELLMAGIC 0x2123 /* #! */ 76 #else 77 #define SHELLMAGIC 0x2321 78 #endif 79 80 /* 81 * Allow the sendsig functions to use the ldebug() facility 82 * even though they are not syscalls themselves. Map them 83 * to syscall 0. This is slightly less bogus than using 84 * ldebug(sigreturn). 85 */ 86 #define LINUX_SYS_linux_rt_sendsig 0 87 #define LINUX_SYS_linux_sendsig 0 88 89 #define fldcw(addr) __asm("fldcw %0" : : "m" (*(addr))) 90 #define __LINUX_NPXCW__ 0x37f 91 92 extern char linux_sigcode[]; 93 extern int linux_szsigcode; 94 95 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; 96 97 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler); 98 SET_DECLARE(linux_device_handler_set, struct linux_device_handler); 99 100 static int linux_fixup(register_t **stack_base, 101 struct image_params *iparams); 102 static int elf_linux_fixup(register_t **stack_base, 103 struct image_params *iparams); 104 static void linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, 105 caddr_t *params); 106 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask); 107 static void exec_linux_setregs(struct thread *td, u_long entry, 108 u_long stack, u_long ps_strings); 109 110 extern LIST_HEAD(futex_list, futex) futex_list; 111 extern struct sx futex_sx; 112 113 static eventhandler_tag linux_exit_tag; 114 static eventhandler_tag linux_schedtail_tag; 115 static eventhandler_tag linux_exec_tag; 116 117 /* 118 * Linux syscalls return negative errno's, we do positive and map them 119 * Reference: 120 * FreeBSD: src/sys/sys/errno.h 121 * Linux: linux-2.6.17.8/include/asm-generic/errno-base.h 122 * linux-2.6.17.8/include/asm-generic/errno.h 123 */ 124 static int bsd_to_linux_errno[ELAST + 1] = { 125 -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, 126 -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, 127 -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, 128 -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, 129 -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, 130 -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, 131 -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, 132 -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, 133 -6, -6, -43, -42, -75,-125, -84, -95, -16, -74, 134 -72, -67, -71 135 }; 136 137 int bsd_to_linux_signal[LINUX_SIGTBLSZ] = { 138 LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, LINUX_SIGILL, 139 LINUX_SIGTRAP, LINUX_SIGABRT, 0, LINUX_SIGFPE, 140 LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, LINUX_SIGSYS, 141 LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, LINUX_SIGURG, 142 LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, LINUX_SIGCHLD, 143 LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, LINUX_SIGXCPU, 144 LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, LINUX_SIGWINCH, 145 0, LINUX_SIGUSR1, LINUX_SIGUSR2 146 }; 147 148 int linux_to_bsd_signal[LINUX_SIGTBLSZ] = { 149 SIGHUP, SIGINT, SIGQUIT, SIGILL, 150 SIGTRAP, SIGABRT, SIGBUS, SIGFPE, 151 SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, 152 SIGPIPE, SIGALRM, SIGTERM, SIGBUS, 153 SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, 154 SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, 155 SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, 156 SIGIO, SIGURG, SIGSYS 157 }; 158 159 #define LINUX_T_UNKNOWN 255 160 static int _bsd_to_linux_trapcode[] = { 161 LINUX_T_UNKNOWN, /* 0 */ 162 6, /* 1 T_PRIVINFLT */ 163 LINUX_T_UNKNOWN, /* 2 */ 164 3, /* 3 T_BPTFLT */ 165 LINUX_T_UNKNOWN, /* 4 */ 166 LINUX_T_UNKNOWN, /* 5 */ 167 16, /* 6 T_ARITHTRAP */ 168 254, /* 7 T_ASTFLT */ 169 LINUX_T_UNKNOWN, /* 8 */ 170 13, /* 9 T_PROTFLT */ 171 1, /* 10 T_TRCTRAP */ 172 LINUX_T_UNKNOWN, /* 11 */ 173 14, /* 12 T_PAGEFLT */ 174 LINUX_T_UNKNOWN, /* 13 */ 175 17, /* 14 T_ALIGNFLT */ 176 LINUX_T_UNKNOWN, /* 15 */ 177 LINUX_T_UNKNOWN, /* 16 */ 178 LINUX_T_UNKNOWN, /* 17 */ 179 0, /* 18 T_DIVIDE */ 180 2, /* 19 T_NMI */ 181 4, /* 20 T_OFLOW */ 182 5, /* 21 T_BOUND */ 183 7, /* 22 T_DNA */ 184 8, /* 23 T_DOUBLEFLT */ 185 9, /* 24 T_FPOPFLT */ 186 10, /* 25 T_TSSFLT */ 187 11, /* 26 T_SEGNPFLT */ 188 12, /* 27 T_STKFLT */ 189 18, /* 28 T_MCHK */ 190 19, /* 29 T_XMMFLT */ 191 15 /* 30 T_RESERVED */ 192 }; 193 #define bsd_to_linux_trapcode(code) \ 194 ((code)<sizeof(_bsd_to_linux_trapcode)/sizeof(*_bsd_to_linux_trapcode)? \ 195 _bsd_to_linux_trapcode[(code)]: \ 196 LINUX_T_UNKNOWN) 197 198 /* 199 * If FreeBSD & Linux have a difference of opinion about what a trap 200 * means, deal with it here. 201 * 202 * MPSAFE 203 */ 204 static int 205 translate_traps(int signal, int trap_code) 206 { 207 if (signal != SIGBUS) 208 return signal; 209 switch (trap_code) { 210 case T_PROTFLT: 211 case T_TSSFLT: 212 case T_DOUBLEFLT: 213 case T_PAGEFLT: 214 return SIGSEGV; 215 default: 216 return signal; 217 } 218 } 219 220 static int 221 linux_fixup(register_t **stack_base, struct image_params *imgp) 222 { 223 register_t *argv, *envp; 224 225 argv = *stack_base; 226 envp = *stack_base + (imgp->args->argc + 1); 227 (*stack_base)--; 228 **stack_base = (intptr_t)(void *)envp; 229 (*stack_base)--; 230 **stack_base = (intptr_t)(void *)argv; 231 (*stack_base)--; 232 **stack_base = imgp->args->argc; 233 return 0; 234 } 235 236 static int 237 elf_linux_fixup(register_t **stack_base, struct image_params *imgp) 238 { 239 Elf32_Auxargs *args; 240 register_t *pos; 241 242 KASSERT(curthread->td_proc == imgp->proc && 243 (curthread->td_proc->p_flag & P_SA) == 0, 244 ("unsafe elf_linux_fixup(), should be curproc")); 245 args = (Elf32_Auxargs *)imgp->auxargs; 246 pos = *stack_base + (imgp->args->argc + imgp->args->envc + 2); 247 248 if (args->trace) 249 AUXARGS_ENTRY(pos, AT_DEBUG, 1); 250 if (args->execfd != -1) 251 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 252 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 253 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 254 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 255 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 256 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 257 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 258 AUXARGS_ENTRY(pos, AT_BASE, args->base); 259 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); 260 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); 261 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); 262 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid); 263 AUXARGS_ENTRY(pos, AT_NULL, 0); 264 265 free(imgp->auxargs, M_TEMP); 266 imgp->auxargs = NULL; 267 268 (*stack_base)--; 269 **stack_base = (register_t)imgp->args->argc; 270 return 0; 271 } 272 273 extern int _ucodesel, _udatasel; 274 extern unsigned long linux_sznonrtsigcode; 275 276 static void 277 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 278 { 279 struct thread *td = curthread; 280 struct proc *p = td->td_proc; 281 struct sigacts *psp; 282 struct trapframe *regs; 283 struct l_rt_sigframe *fp, frame; 284 int sig, code; 285 int oonstack; 286 287 sig = ksi->ksi_signo; 288 code = ksi->ksi_code; 289 PROC_LOCK_ASSERT(p, MA_OWNED); 290 psp = p->p_sigacts; 291 mtx_assert(&psp->ps_mtx, MA_OWNED); 292 regs = td->td_frame; 293 oonstack = sigonstack(regs->tf_esp); 294 295 #ifdef DEBUG 296 if (ldebug(rt_sendsig)) 297 printf(ARGS(rt_sendsig, "%p, %d, %p, %u"), 298 catcher, sig, (void*)mask, code); 299 #endif 300 /* 301 * Allocate space for the signal handler context. 302 */ 303 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 304 SIGISMEMBER(psp->ps_sigonstack, sig)) { 305 fp = (struct l_rt_sigframe *)(td->td_sigstk.ss_sp + 306 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe)); 307 } else 308 fp = (struct l_rt_sigframe *)regs->tf_esp - 1; 309 mtx_unlock(&psp->ps_mtx); 310 311 /* 312 * Build the argument list for the signal handler. 313 */ 314 if (p->p_sysent->sv_sigtbl) 315 if (sig <= p->p_sysent->sv_sigsize) 316 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 317 318 bzero(&frame, sizeof(frame)); 319 320 frame.sf_handler = catcher; 321 frame.sf_sig = sig; 322 frame.sf_siginfo = &fp->sf_si; 323 frame.sf_ucontext = &fp->sf_sc; 324 325 /* Fill in POSIX parts */ 326 frame.sf_si.lsi_signo = sig; 327 frame.sf_si.lsi_code = code; 328 frame.sf_si.lsi_addr = ksi->ksi_addr; 329 330 /* 331 * Build the signal context to be used by sigreturn. 332 */ 333 frame.sf_sc.uc_flags = 0; /* XXX ??? */ 334 frame.sf_sc.uc_link = NULL; /* XXX ??? */ 335 336 frame.sf_sc.uc_stack.ss_sp = td->td_sigstk.ss_sp; 337 frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size; 338 frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK) 339 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE; 340 PROC_UNLOCK(p); 341 342 bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask); 343 344 frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__bits[0]; 345 frame.sf_sc.uc_mcontext.sc_gs = rgs(); 346 frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs; 347 frame.sf_sc.uc_mcontext.sc_es = regs->tf_es; 348 frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds; 349 frame.sf_sc.uc_mcontext.sc_edi = regs->tf_edi; 350 frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi; 351 frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp; 352 frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx; 353 frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx; 354 frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx; 355 frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax; 356 frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip; 357 frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs; 358 frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags; 359 frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp; 360 frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss; 361 frame.sf_sc.uc_mcontext.sc_err = regs->tf_err; 362 frame.sf_sc.uc_mcontext.sc_cr2 = (register_t)ksi->ksi_addr; 363 frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code); 364 365 #ifdef DEBUG 366 if (ldebug(rt_sendsig)) 367 printf(LMSG("rt_sendsig flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 368 frame.sf_sc.uc_stack.ss_flags, td->td_sigstk.ss_sp, 369 td->td_sigstk.ss_size, frame.sf_sc.uc_mcontext.sc_mask); 370 #endif 371 372 if (copyout(&frame, fp, sizeof(frame)) != 0) { 373 /* 374 * Process has trashed its stack; give it an illegal 375 * instruction to halt it in its tracks. 376 */ 377 #ifdef DEBUG 378 if (ldebug(rt_sendsig)) 379 printf(LMSG("rt_sendsig: bad stack %p, oonstack=%x"), 380 fp, oonstack); 381 #endif 382 PROC_LOCK(p); 383 sigexit(td, SIGILL); 384 } 385 386 /* 387 * Build context to run handler in. 388 */ 389 regs->tf_esp = (int)fp; 390 regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode) + 391 linux_sznonrtsigcode; 392 regs->tf_eflags &= ~(PSL_T | PSL_VM); 393 regs->tf_cs = _ucodesel; 394 regs->tf_ds = _udatasel; 395 regs->tf_es = _udatasel; 396 regs->tf_fs = _udatasel; 397 regs->tf_ss = _udatasel; 398 PROC_LOCK(p); 399 mtx_lock(&psp->ps_mtx); 400 } 401 402 403 /* 404 * Send an interrupt to process. 405 * 406 * Stack is set up to allow sigcode stored 407 * in u. to call routine, followed by kcall 408 * to sigreturn routine below. After sigreturn 409 * resets the signal mask, the stack, and the 410 * frame pointer, it returns to the user 411 * specified pc, psl. 412 */ 413 static void 414 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask) 415 { 416 struct thread *td = curthread; 417 struct proc *p = td->td_proc; 418 struct sigacts *psp; 419 struct trapframe *regs; 420 struct l_sigframe *fp, frame; 421 l_sigset_t lmask; 422 int sig, code; 423 int oonstack, i; 424 425 PROC_LOCK_ASSERT(p, MA_OWNED); 426 psp = p->p_sigacts; 427 sig = ksi->ksi_signo; 428 code = ksi->ksi_code; 429 mtx_assert(&psp->ps_mtx, MA_OWNED); 430 if (SIGISMEMBER(psp->ps_siginfo, sig)) { 431 /* Signal handler installed with SA_SIGINFO. */ 432 linux_rt_sendsig(catcher, ksi, mask); 433 return; 434 } 435 regs = td->td_frame; 436 oonstack = sigonstack(regs->tf_esp); 437 438 #ifdef DEBUG 439 if (ldebug(sendsig)) 440 printf(ARGS(sendsig, "%p, %d, %p, %u"), 441 catcher, sig, (void*)mask, code); 442 #endif 443 444 /* 445 * Allocate space for the signal handler context. 446 */ 447 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack && 448 SIGISMEMBER(psp->ps_sigonstack, sig)) { 449 fp = (struct l_sigframe *)(td->td_sigstk.ss_sp + 450 td->td_sigstk.ss_size - sizeof(struct l_sigframe)); 451 } else 452 fp = (struct l_sigframe *)regs->tf_esp - 1; 453 mtx_unlock(&psp->ps_mtx); 454 PROC_UNLOCK(p); 455 456 /* 457 * Build the argument list for the signal handler. 458 */ 459 if (p->p_sysent->sv_sigtbl) 460 if (sig <= p->p_sysent->sv_sigsize) 461 sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; 462 463 bzero(&frame, sizeof(frame)); 464 465 frame.sf_handler = catcher; 466 frame.sf_sig = sig; 467 468 bsd_to_linux_sigset(mask, &lmask); 469 470 /* 471 * Build the signal context to be used by sigreturn. 472 */ 473 frame.sf_sc.sc_mask = lmask.__bits[0]; 474 frame.sf_sc.sc_gs = rgs(); 475 frame.sf_sc.sc_fs = regs->tf_fs; 476 frame.sf_sc.sc_es = regs->tf_es; 477 frame.sf_sc.sc_ds = regs->tf_ds; 478 frame.sf_sc.sc_edi = regs->tf_edi; 479 frame.sf_sc.sc_esi = regs->tf_esi; 480 frame.sf_sc.sc_ebp = regs->tf_ebp; 481 frame.sf_sc.sc_ebx = regs->tf_ebx; 482 frame.sf_sc.sc_edx = regs->tf_edx; 483 frame.sf_sc.sc_ecx = regs->tf_ecx; 484 frame.sf_sc.sc_eax = regs->tf_eax; 485 frame.sf_sc.sc_eip = regs->tf_eip; 486 frame.sf_sc.sc_cs = regs->tf_cs; 487 frame.sf_sc.sc_eflags = regs->tf_eflags; 488 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 489 frame.sf_sc.sc_ss = regs->tf_ss; 490 frame.sf_sc.sc_err = regs->tf_err; 491 frame.sf_sc.sc_cr2 = (register_t)ksi->ksi_addr; 492 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(ksi->ksi_trapno); 493 494 for (i = 0; i < (LINUX_NSIG_WORDS-1); i++) 495 frame.sf_extramask[i] = lmask.__bits[i+1]; 496 497 if (copyout(&frame, fp, sizeof(frame)) != 0) { 498 /* 499 * Process has trashed its stack; give it an illegal 500 * instruction to halt it in its tracks. 501 */ 502 PROC_LOCK(p); 503 sigexit(td, SIGILL); 504 } 505 506 /* 507 * Build context to run handler in. 508 */ 509 regs->tf_esp = (int)fp; 510 regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode); 511 regs->tf_eflags &= ~(PSL_T | PSL_VM); 512 regs->tf_cs = _ucodesel; 513 regs->tf_ds = _udatasel; 514 regs->tf_es = _udatasel; 515 regs->tf_fs = _udatasel; 516 regs->tf_ss = _udatasel; 517 PROC_LOCK(p); 518 mtx_lock(&psp->ps_mtx); 519 } 520 521 /* 522 * System call to cleanup state after a signal 523 * has been taken. Reset signal mask and 524 * stack state from context left by sendsig (above). 525 * Return to previous pc and psl as specified by 526 * context left by sendsig. Check carefully to 527 * make sure that the user has not modified the 528 * psl to gain improper privileges or to cause 529 * a machine fault. 530 */ 531 int 532 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args) 533 { 534 struct proc *p = td->td_proc; 535 struct l_sigframe frame; 536 struct trapframe *regs; 537 l_sigset_t lmask; 538 int eflags, i; 539 ksiginfo_t ksi; 540 541 regs = td->td_frame; 542 543 #ifdef DEBUG 544 if (ldebug(sigreturn)) 545 printf(ARGS(sigreturn, "%p"), (void *)args->sfp); 546 #endif 547 /* 548 * The trampoline code hands us the sigframe. 549 * It is unsafe to keep track of it ourselves, in the event that a 550 * program jumps out of a signal handler. 551 */ 552 if (copyin(args->sfp, &frame, sizeof(frame)) != 0) 553 return (EFAULT); 554 555 /* 556 * Check for security violations. 557 */ 558 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 559 eflags = frame.sf_sc.sc_eflags; 560 /* 561 * XXX do allow users to change the privileged flag PSL_RF. The 562 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 563 * sometimes set it there too. tf_eflags is kept in the signal 564 * context during signal handling and there is no other place 565 * to remember it, so the PSL_RF bit may be corrupted by the 566 * signal handler without us knowing. Corruption of the PSL_RF 567 * bit at worst causes one more or one less debugger trap, so 568 * allowing it is fairly harmless. 569 */ 570 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) 571 return(EINVAL); 572 573 /* 574 * Don't allow users to load a valid privileged %cs. Let the 575 * hardware check for invalid selectors, excess privilege in 576 * other selectors, invalid %eip's and invalid %esp's. 577 */ 578 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 579 if (!CS_SECURE(frame.sf_sc.sc_cs)) { 580 ksiginfo_init_trap(&ksi); 581 ksi.ksi_signo = SIGBUS; 582 ksi.ksi_code = BUS_OBJERR; 583 ksi.ksi_trapno = T_PROTFLT; 584 ksi.ksi_addr = (void *)regs->tf_eip; 585 trapsignal(td, &ksi); 586 return(EINVAL); 587 } 588 589 lmask.__bits[0] = frame.sf_sc.sc_mask; 590 for (i = 0; i < (LINUX_NSIG_WORDS-1); i++) 591 lmask.__bits[i+1] = frame.sf_extramask[i]; 592 PROC_LOCK(p); 593 linux_to_bsd_sigset(&lmask, &td->td_sigmask); 594 SIG_CANTMASK(td->td_sigmask); 595 signotify(td); 596 PROC_UNLOCK(p); 597 598 /* 599 * Restore signal context. 600 */ 601 /* %gs was restored by the trampoline. */ 602 regs->tf_fs = frame.sf_sc.sc_fs; 603 regs->tf_es = frame.sf_sc.sc_es; 604 regs->tf_ds = frame.sf_sc.sc_ds; 605 regs->tf_edi = frame.sf_sc.sc_edi; 606 regs->tf_esi = frame.sf_sc.sc_esi; 607 regs->tf_ebp = frame.sf_sc.sc_ebp; 608 regs->tf_ebx = frame.sf_sc.sc_ebx; 609 regs->tf_edx = frame.sf_sc.sc_edx; 610 regs->tf_ecx = frame.sf_sc.sc_ecx; 611 regs->tf_eax = frame.sf_sc.sc_eax; 612 regs->tf_eip = frame.sf_sc.sc_eip; 613 regs->tf_cs = frame.sf_sc.sc_cs; 614 regs->tf_eflags = eflags; 615 regs->tf_esp = frame.sf_sc.sc_esp_at_signal; 616 regs->tf_ss = frame.sf_sc.sc_ss; 617 618 return (EJUSTRETURN); 619 } 620 621 /* 622 * System call to cleanup state after a signal 623 * has been taken. Reset signal mask and 624 * stack state from context left by rt_sendsig (above). 625 * Return to previous pc and psl as specified by 626 * context left by sendsig. Check carefully to 627 * make sure that the user has not modified the 628 * psl to gain improper privileges or to cause 629 * a machine fault. 630 */ 631 int 632 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args) 633 { 634 struct proc *p = td->td_proc; 635 struct l_ucontext uc; 636 struct l_sigcontext *context; 637 l_stack_t *lss; 638 stack_t ss; 639 struct trapframe *regs; 640 int eflags; 641 ksiginfo_t ksi; 642 643 regs = td->td_frame; 644 645 #ifdef DEBUG 646 if (ldebug(rt_sigreturn)) 647 printf(ARGS(rt_sigreturn, "%p"), (void *)args->ucp); 648 #endif 649 /* 650 * The trampoline code hands us the ucontext. 651 * It is unsafe to keep track of it ourselves, in the event that a 652 * program jumps out of a signal handler. 653 */ 654 if (copyin(args->ucp, &uc, sizeof(uc)) != 0) 655 return (EFAULT); 656 657 context = &uc.uc_mcontext; 658 659 /* 660 * Check for security violations. 661 */ 662 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 663 eflags = context->sc_eflags; 664 /* 665 * XXX do allow users to change the privileged flag PSL_RF. The 666 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 667 * sometimes set it there too. tf_eflags is kept in the signal 668 * context during signal handling and there is no other place 669 * to remember it, so the PSL_RF bit may be corrupted by the 670 * signal handler without us knowing. Corruption of the PSL_RF 671 * bit at worst causes one more or one less debugger trap, so 672 * allowing it is fairly harmless. 673 */ 674 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) 675 return(EINVAL); 676 677 /* 678 * Don't allow users to load a valid privileged %cs. Let the 679 * hardware check for invalid selectors, excess privilege in 680 * other selectors, invalid %eip's and invalid %esp's. 681 */ 682 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 683 if (!CS_SECURE(context->sc_cs)) { 684 ksiginfo_init_trap(&ksi); 685 ksi.ksi_signo = SIGBUS; 686 ksi.ksi_code = BUS_OBJERR; 687 ksi.ksi_trapno = T_PROTFLT; 688 ksi.ksi_addr = (void *)regs->tf_eip; 689 trapsignal(td, &ksi); 690 return(EINVAL); 691 } 692 693 PROC_LOCK(p); 694 linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask); 695 SIG_CANTMASK(td->td_sigmask); 696 signotify(td); 697 PROC_UNLOCK(p); 698 699 /* 700 * Restore signal context 701 */ 702 /* %gs was restored by the trampoline. */ 703 regs->tf_fs = context->sc_fs; 704 regs->tf_es = context->sc_es; 705 regs->tf_ds = context->sc_ds; 706 regs->tf_edi = context->sc_edi; 707 regs->tf_esi = context->sc_esi; 708 regs->tf_ebp = context->sc_ebp; 709 regs->tf_ebx = context->sc_ebx; 710 regs->tf_edx = context->sc_edx; 711 regs->tf_ecx = context->sc_ecx; 712 regs->tf_eax = context->sc_eax; 713 regs->tf_eip = context->sc_eip; 714 regs->tf_cs = context->sc_cs; 715 regs->tf_eflags = eflags; 716 regs->tf_esp = context->sc_esp_at_signal; 717 regs->tf_ss = context->sc_ss; 718 719 /* 720 * call sigaltstack & ignore results.. 721 */ 722 lss = &uc.uc_stack; 723 ss.ss_sp = lss->ss_sp; 724 ss.ss_size = lss->ss_size; 725 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags); 726 727 #ifdef DEBUG 728 if (ldebug(rt_sigreturn)) 729 printf(LMSG("rt_sigret flags: 0x%x, sp: %p, ss: 0x%x, mask: 0x%x"), 730 ss.ss_flags, ss.ss_sp, ss.ss_size, context->sc_mask); 731 #endif 732 (void)kern_sigaltstack(td, &ss, NULL); 733 734 return (EJUSTRETURN); 735 } 736 737 /* 738 * MPSAFE 739 */ 740 static void 741 linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params) 742 { 743 args[0] = tf->tf_ebx; 744 args[1] = tf->tf_ecx; 745 args[2] = tf->tf_edx; 746 args[3] = tf->tf_esi; 747 args[4] = tf->tf_edi; 748 args[5] = tf->tf_ebp; /* Unconfirmed */ 749 *params = NULL; /* no copyin */ 750 } 751 752 /* 753 * If a linux binary is exec'ing something, try this image activator 754 * first. We override standard shell script execution in order to 755 * be able to modify the interpreter path. We only do this if a linux 756 * binary is doing the exec, so we do not create an EXEC module for it. 757 */ 758 static int exec_linux_imgact_try(struct image_params *iparams); 759 760 static int 761 exec_linux_imgact_try(struct image_params *imgp) 762 { 763 const char *head = (const char *)imgp->image_header; 764 char *rpath; 765 int error = -1, len; 766 767 /* 768 * The interpreter for shell scripts run from a linux binary needs 769 * to be located in /compat/linux if possible in order to recursively 770 * maintain linux path emulation. 771 */ 772 if (((const short *)head)[0] == SHELLMAGIC) { 773 /* 774 * Run our normal shell image activator. If it succeeds attempt 775 * to use the alternate path for the interpreter. If an alternate 776 * path is found, use our stringspace to store it. 777 */ 778 if ((error = exec_shell_imgact(imgp)) == 0) { 779 linux_emul_convpath(FIRST_THREAD_IN_PROC(imgp->proc), 780 imgp->interpreter_name, UIO_SYSSPACE, &rpath, 0); 781 if (rpath != NULL) { 782 len = strlen(rpath) + 1; 783 784 if (len <= MAXSHELLCMDLEN) { 785 memcpy(imgp->interpreter_name, rpath, len); 786 } 787 free(rpath, M_TEMP); 788 } 789 } 790 } 791 return(error); 792 } 793 794 /* 795 * exec_setregs may initialize some registers differently than Linux 796 * does, thus potentially confusing Linux binaries. If necessary, we 797 * override the exec_setregs default(s) here. 798 */ 799 static void 800 exec_linux_setregs(struct thread *td, u_long entry, 801 u_long stack, u_long ps_strings) 802 { 803 static const u_short control = __LINUX_NPXCW__; 804 struct pcb *pcb = td->td_pcb; 805 806 exec_setregs(td, entry, stack, ps_strings); 807 808 /* Linux sets %gs to 0, we default to _udatasel */ 809 pcb->pcb_gs = 0; load_gs(0); 810 811 /* Linux sets the i387 to extended precision. */ 812 fldcw(&control); 813 } 814 815 struct sysentvec linux_sysvec = { 816 LINUX_SYS_MAXSYSCALL, 817 linux_sysent, 818 0, 819 LINUX_SIGTBLSZ, 820 bsd_to_linux_signal, 821 ELAST + 1, 822 bsd_to_linux_errno, 823 translate_traps, 824 linux_fixup, 825 linux_sendsig, 826 linux_sigcode, 827 &linux_szsigcode, 828 linux_prepsyscall, 829 "Linux a.out", 830 NULL, 831 exec_linux_imgact_try, 832 LINUX_MINSIGSTKSZ, 833 PAGE_SIZE, 834 VM_MIN_ADDRESS, 835 VM_MAXUSER_ADDRESS, 836 USRSTACK, 837 PS_STRINGS, 838 VM_PROT_ALL, 839 exec_copyout_strings, 840 exec_linux_setregs, 841 NULL 842 }; 843 844 struct sysentvec elf_linux_sysvec = { 845 LINUX_SYS_MAXSYSCALL, 846 linux_sysent, 847 0, 848 LINUX_SIGTBLSZ, 849 bsd_to_linux_signal, 850 ELAST + 1, 851 bsd_to_linux_errno, 852 translate_traps, 853 elf_linux_fixup, 854 linux_sendsig, 855 linux_sigcode, 856 &linux_szsigcode, 857 linux_prepsyscall, 858 "Linux ELF", 859 elf32_coredump, 860 exec_linux_imgact_try, 861 LINUX_MINSIGSTKSZ, 862 PAGE_SIZE, 863 VM_MIN_ADDRESS, 864 VM_MAXUSER_ADDRESS, 865 USRSTACK, 866 PS_STRINGS, 867 VM_PROT_ALL, 868 exec_copyout_strings, 869 exec_linux_setregs, 870 NULL 871 }; 872 873 static Elf32_Brandinfo linux_brand = { 874 ELFOSABI_LINUX, 875 EM_386, 876 "Linux", 877 "/compat/linux", 878 "/lib/ld-linux.so.1", 879 &elf_linux_sysvec, 880 NULL, 881 BI_CAN_EXEC_DYN, 882 }; 883 884 static Elf32_Brandinfo linux_glibc2brand = { 885 ELFOSABI_LINUX, 886 EM_386, 887 "Linux", 888 "/compat/linux", 889 "/lib/ld-linux.so.2", 890 &elf_linux_sysvec, 891 NULL, 892 BI_CAN_EXEC_DYN, 893 }; 894 895 Elf32_Brandinfo *linux_brandlist[] = { 896 &linux_brand, 897 &linux_glibc2brand, 898 NULL 899 }; 900 901 static int 902 linux_elf_modevent(module_t mod, int type, void *data) 903 { 904 Elf32_Brandinfo **brandinfo; 905 int error; 906 struct linux_ioctl_handler **lihp; 907 struct linux_device_handler **ldhp; 908 909 error = 0; 910 911 switch(type) { 912 case MOD_LOAD: 913 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 914 ++brandinfo) 915 if (elf32_insert_brand_entry(*brandinfo) < 0) 916 error = EINVAL; 917 if (error == 0) { 918 SET_FOREACH(lihp, linux_ioctl_handler_set) 919 linux_ioctl_register_handler(*lihp); 920 SET_FOREACH(ldhp, linux_device_handler_set) 921 linux_device_register_handler(*ldhp); 922 mtx_init(&emul_lock, "emuldata lock", NULL, MTX_DEF); 923 sx_init(&emul_shared_lock, "emuldata->shared lock"); 924 LIST_INIT(&futex_list); 925 sx_init(&futex_sx, "futex protection lock"); 926 linux_exit_tag = EVENTHANDLER_REGISTER(process_exit, linux_proc_exit, 927 NULL, 1000); 928 linux_schedtail_tag = EVENTHANDLER_REGISTER(schedtail, linux_schedtail, 929 NULL, 1000); 930 linux_exec_tag = EVENTHANDLER_REGISTER(process_exec, linux_proc_exec, 931 NULL, 1000); 932 if (bootverbose) 933 printf("Linux ELF exec handler installed\n"); 934 } else 935 printf("cannot insert Linux ELF brand handler\n"); 936 break; 937 case MOD_UNLOAD: 938 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 939 ++brandinfo) 940 if (elf32_brand_inuse(*brandinfo)) 941 error = EBUSY; 942 if (error == 0) { 943 for (brandinfo = &linux_brandlist[0]; 944 *brandinfo != NULL; ++brandinfo) 945 if (elf32_remove_brand_entry(*brandinfo) < 0) 946 error = EINVAL; 947 } 948 if (error == 0) { 949 SET_FOREACH(lihp, linux_ioctl_handler_set) 950 linux_ioctl_unregister_handler(*lihp); 951 SET_FOREACH(ldhp, linux_device_handler_set) 952 linux_device_unregister_handler(*ldhp); 953 mtx_destroy(&emul_lock); 954 sx_destroy(&emul_shared_lock); 955 sx_destroy(&futex_sx); 956 EVENTHANDLER_DEREGISTER(process_exit, linux_exit_tag); 957 EVENTHANDLER_DEREGISTER(schedtail, linux_schedtail_tag); 958 EVENTHANDLER_DEREGISTER(process_exec, linux_exec_tag); 959 if (bootverbose) 960 printf("Linux ELF exec handler removed\n"); 961 } else 962 printf("Could not deinstall ELF interpreter entry\n"); 963 break; 964 default: 965 return EOPNOTSUPP; 966 } 967 return error; 968 } 969 970 static moduledata_t linux_elf_mod = { 971 "linuxelf", 972 linux_elf_modevent, 973 0 974 }; 975 976 DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
Cache object: f1f5593022e7cd38618f20c7515b50d9
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