1 /*- 2 * Copyright (c) 1994-1996 S�ren 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 withough 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 * $Id: linux_sysvec.c,v 1.44 1999/01/17 20:36:14 peter Exp $ 29 */ 30 31 /* XXX we use functions that might not exist. */ 32 #include "opt_compat.h" 33 34 #ifndef COMPAT_43 35 #error "Unable to compile Linux-emulator due to missing COMPAT_43 option!" 36 #endif 37 38 #include <sys/param.h> 39 #include <sys/buf.h> 40 #include <sys/proc.h> 41 #include <sys/systm.h> 42 #include <sys/sysent.h> 43 #include <sys/imgact.h> 44 #include <sys/imgact_aout.h> 45 #include <sys/imgact_elf.h> 46 #include <sys/signalvar.h> 47 #include <sys/malloc.h> 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #include <vm/vm_prot.h> 51 #include <vm/vm_page.h> 52 #include <vm/vm_extern.h> 53 #include <sys/exec.h> 54 #include <sys/kernel.h> 55 #include <sys/module.h> 56 #include <machine/cpu.h> 57 58 #include <i386/linux/linux.h> 59 #include <i386/linux/linux_proto.h> 60 61 static int linux_fixup __P((long **stack_base, 62 struct image_params *iparams)); 63 static int elf_linux_fixup __P((long **stack_base, 64 struct image_params *iparams)); 65 static void linux_prepsyscall __P((struct trapframe *tf, int *args, 66 u_int *code, caddr_t *params)); 67 static void linux_sendsig __P((sig_t catcher, int sig, int mask, 68 u_long code)); 69 70 /* 71 * Linux syscalls return negative errno's, we do positive and map them 72 */ 73 static int bsd_to_linux_errno[ELAST + 1] = { 74 -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, 75 -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, 76 -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, 77 -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, 78 -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, 79 -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, 80 -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, 81 -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, 82 -6, -6, -43, -42, -75, -6, -84 83 }; 84 85 int bsd_to_linux_signal[NSIG] = { 86 0, LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, 87 LINUX_SIGILL, LINUX_SIGTRAP, LINUX_SIGABRT, 0, 88 LINUX_SIGFPE, LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, 89 0, LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, 90 LINUX_SIGURG, LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, 91 LINUX_SIGCHLD, LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, 92 LINUX_SIGXCPU, LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, 93 LINUX_SIGWINCH, 0, LINUX_SIGUSR1, LINUX_SIGUSR2 94 }; 95 96 int linux_to_bsd_signal[LINUX_NSIG] = { 97 0, SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, 98 SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, 99 SIGBUS, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, 100 SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGURG, 0 101 }; 102 103 /* 104 * If FreeBSD & Linux have a difference of opinion about what a trap 105 * means, deal with it here. 106 */ 107 static int 108 translate_traps(int signal, int trap_code) 109 { 110 if (signal != SIGBUS) 111 return signal; 112 switch (trap_code) { 113 case T_PROTFLT: 114 case T_TSSFLT: 115 case T_DOUBLEFLT: 116 case T_PAGEFLT: 117 return SIGSEGV; 118 default: 119 return signal; 120 } 121 } 122 123 static int 124 linux_fixup(long **stack_base, struct image_params *imgp) 125 { 126 long *argv, *envp; 127 128 argv = *stack_base; 129 envp = *stack_base + (imgp->argc + 1); 130 (*stack_base)--; 131 **stack_base = (intptr_t)(void *)envp; 132 (*stack_base)--; 133 **stack_base = (intptr_t)(void *)argv; 134 (*stack_base)--; 135 **stack_base = imgp->argc; 136 return 0; 137 } 138 139 static int 140 elf_linux_fixup(long **stack_base, struct image_params *imgp) 141 { 142 Elf32_Auxargs *args = (Elf32_Auxargs *)imgp->auxargs; 143 long *pos; 144 145 pos = *stack_base + (imgp->argc + imgp->envc + 2); 146 147 if (args->trace) { 148 AUXARGS_ENTRY(pos, AT_DEBUG, 1); 149 } 150 if (args->execfd != -1) { 151 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); 152 } 153 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); 154 AUXARGS_ENTRY(pos, AT_PHENT, args->phent); 155 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); 156 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); 157 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); 158 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); 159 AUXARGS_ENTRY(pos, AT_BASE, args->base); 160 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_cred->p_ruid); 161 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_cred->p_svuid); 162 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_cred->p_rgid); 163 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_cred->p_svgid); 164 AUXARGS_ENTRY(pos, AT_NULL, 0); 165 166 free(imgp->auxargs, M_TEMP); 167 imgp->auxargs = NULL; 168 169 (*stack_base)--; 170 **stack_base = (long)imgp->argc; 171 return 0; 172 } 173 174 extern int _ucodesel, _udatasel; 175 176 /* 177 * Send an interrupt to process. 178 * 179 * Stack is set up to allow sigcode stored 180 * in u. to call routine, followed by kcall 181 * to sigreturn routine below. After sigreturn 182 * resets the signal mask, the stack, and the 183 * frame pointer, it returns to the user 184 * specified pc, psl. 185 */ 186 187 static void 188 linux_sendsig(sig_t catcher, int sig, int mask, u_long code) 189 { 190 register struct proc *p = curproc; 191 register struct trapframe *regs; 192 struct linux_sigframe *fp, frame; 193 struct sigacts *psp = p->p_sigacts; 194 int oonstack; 195 196 regs = p->p_md.md_regs; 197 oonstack = psp->ps_sigstk.ss_flags & SS_ONSTACK; 198 199 #ifdef DEBUG 200 printf("Linux-emul(%ld): linux_sendsig(%p, %d, %d, %lu)\n", 201 (long)p->p_pid, catcher, sig, mask, code); 202 #endif 203 /* 204 * Allocate space for the signal handler context. 205 */ 206 if ((psp->ps_flags & SAS_ALTSTACK) && !oonstack && 207 (psp->ps_sigonstack & sigmask(sig))) { 208 fp = (struct linux_sigframe *)(psp->ps_sigstk.ss_sp + 209 psp->ps_sigstk.ss_size - sizeof(struct linux_sigframe)); 210 psp->ps_sigstk.ss_flags |= SS_ONSTACK; 211 } else { 212 fp = (struct linux_sigframe *)regs->tf_esp - 1; 213 } 214 215 /* 216 * grow() will return FALSE if the fp will not fit inside the stack 217 * and the stack can not be grown. useracc will return FALSE 218 * if access is denied. 219 */ 220 #ifdef VM_STACK 221 if ((grow_stack (p, (int)fp) == FALSE) || 222 #else 223 if ((grow(p, (int)fp) == FALSE) || 224 #endif 225 (useracc((caddr_t)fp, sizeof (struct linux_sigframe), B_WRITE) == FALSE)) { 226 /* 227 * Process has trashed its stack; give it an illegal 228 * instruction to halt it in its tracks. 229 */ 230 SIGACTION(p, SIGILL) = SIG_DFL; 231 sig = sigmask(SIGILL); 232 p->p_sigignore &= ~sig; 233 p->p_sigcatch &= ~sig; 234 p->p_sigmask &= ~sig; 235 psignal(p, SIGILL); 236 return; 237 } 238 239 /* 240 * Build the argument list for the signal handler. 241 */ 242 if (p->p_sysent->sv_sigtbl) { 243 if (sig < p->p_sysent->sv_sigsize) 244 sig = p->p_sysent->sv_sigtbl[sig]; 245 else 246 sig = p->p_sysent->sv_sigsize + 1; 247 } 248 249 frame.sf_handler = catcher; 250 frame.sf_sig = sig; 251 252 /* 253 * Build the signal context to be used by sigreturn. 254 */ 255 frame.sf_sc.sc_mask = mask; 256 __asm("movl %%gs,%w0" : "=r" (frame.sf_sc.sc_gs)); 257 __asm("movl %%fs,%w0" : "=r" (frame.sf_sc.sc_fs)); 258 frame.sf_sc.sc_es = regs->tf_es; 259 frame.sf_sc.sc_ds = regs->tf_ds; 260 frame.sf_sc.sc_edi = regs->tf_edi; 261 frame.sf_sc.sc_esi = regs->tf_esi; 262 frame.sf_sc.sc_ebp = regs->tf_ebp; 263 frame.sf_sc.sc_ebx = regs->tf_ebx; 264 frame.sf_sc.sc_edx = regs->tf_edx; 265 frame.sf_sc.sc_ecx = regs->tf_ecx; 266 frame.sf_sc.sc_eax = regs->tf_eax; 267 frame.sf_sc.sc_eip = regs->tf_eip; 268 frame.sf_sc.sc_cs = regs->tf_cs; 269 frame.sf_sc.sc_eflags = regs->tf_eflags; 270 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 271 frame.sf_sc.sc_ss = regs->tf_ss; 272 frame.sf_sc.sc_err = regs->tf_err; 273 frame.sf_sc.sc_trapno = code; /* XXX ???? */ 274 275 if (copyout(&frame, fp, sizeof(frame)) != 0) { 276 /* 277 * Process has trashed its stack; give it an illegal 278 * instruction to halt it in its tracks. 279 */ 280 sigexit(p, SIGILL); 281 /* NOTREACHED */ 282 } 283 284 /* 285 * Build context to run handler in. 286 */ 287 regs->tf_esp = (int)fp; 288 regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode); 289 regs->tf_eflags &= ~PSL_VM; 290 regs->tf_cs = _ucodesel; 291 regs->tf_ds = _udatasel; 292 regs->tf_es = _udatasel; 293 regs->tf_ss = _udatasel; 294 } 295 296 /* 297 * System call to cleanup state after a signal 298 * has been taken. Reset signal mask and 299 * stack state from context left by sendsig (above). 300 * Return to previous pc and psl as specified by 301 * context left by sendsig. Check carefully to 302 * make sure that the user has not modified the 303 * psl to gain improper privileges or to cause 304 * a machine fault. 305 */ 306 int 307 linux_sigreturn(p, args) 308 struct proc *p; 309 struct linux_sigreturn_args *args; 310 { 311 struct linux_sigcontext *scp, context; 312 register struct trapframe *regs; 313 int eflags; 314 315 regs = p->p_md.md_regs; 316 317 #ifdef DEBUG 318 printf("Linux-emul(%ld): linux_sigreturn(%p)\n", 319 (long)p->p_pid, (void *)args->scp); 320 #endif 321 /* 322 * The trampoline code hands us the context. 323 * It is unsafe to keep track of it ourselves, in the event that a 324 * program jumps out of a signal handler. 325 */ 326 scp = SCARG(args,scp); 327 if (copyin((caddr_t)scp, &context, sizeof(*scp)) != 0) 328 return (EFAULT); 329 330 /* 331 * Check for security violations. 332 */ 333 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 334 eflags = context.sc_eflags; 335 /* 336 * XXX do allow users to change the privileged flag PSL_RF. The 337 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 338 * sometimes set it there too. tf_eflags is kept in the signal 339 * context during signal handling and there is no other place 340 * to remember it, so the PSL_RF bit may be corrupted by the 341 * signal handler without us knowing. Corruption of the PSL_RF 342 * bit at worst causes one more or one less debugger trap, so 343 * allowing it is fairly harmless. 344 */ 345 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) { 346 return(EINVAL); 347 } 348 349 /* 350 * Don't allow users to load a valid privileged %cs. Let the 351 * hardware check for invalid selectors, excess privilege in 352 * other selectors, invalid %eip's and invalid %esp's. 353 */ 354 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 355 if (!CS_SECURE(context.sc_cs)) { 356 trapsignal(p, SIGBUS, T_PROTFLT); 357 return(EINVAL); 358 } 359 360 p->p_sigacts->ps_sigstk.ss_flags &= ~SS_ONSTACK; 361 p->p_sigmask = context.sc_mask &~ 362 (sigmask(SIGKILL)|sigmask(SIGCONT)|sigmask(SIGSTOP)); 363 /* 364 * Restore signal context. 365 */ 366 /* %fs and %gs were restored by the trampoline. */ 367 regs->tf_es = context.sc_es; 368 regs->tf_ds = context.sc_ds; 369 regs->tf_edi = context.sc_edi; 370 regs->tf_esi = context.sc_esi; 371 regs->tf_ebp = context.sc_ebp; 372 regs->tf_ebx = context.sc_ebx; 373 regs->tf_edx = context.sc_edx; 374 regs->tf_ecx = context.sc_ecx; 375 regs->tf_eax = context.sc_eax; 376 regs->tf_eip = context.sc_eip; 377 regs->tf_cs = context.sc_cs; 378 regs->tf_eflags = eflags; 379 regs->tf_esp = context.sc_esp_at_signal; 380 regs->tf_ss = context.sc_ss; 381 382 return (EJUSTRETURN); 383 } 384 385 static void 386 linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params) 387 { 388 args[0] = tf->tf_ebx; 389 args[1] = tf->tf_ecx; 390 args[2] = tf->tf_edx; 391 args[3] = tf->tf_esi; 392 args[4] = tf->tf_edi; 393 *params = NULL; /* no copyin */ 394 } 395 396 struct sysentvec linux_sysvec = { 397 LINUX_SYS_MAXSYSCALL, 398 linux_sysent, 399 0xff, 400 NSIG, 401 bsd_to_linux_signal, 402 ELAST + 1, 403 bsd_to_linux_errno, 404 translate_traps, 405 linux_fixup, 406 linux_sendsig, 407 linux_sigcode, 408 &linux_szsigcode, 409 linux_prepsyscall, 410 "Linux a.out", 411 aout_coredump 412 }; 413 414 struct sysentvec elf_linux_sysvec = { 415 LINUX_SYS_MAXSYSCALL, 416 linux_sysent, 417 0xff, 418 NSIG, 419 bsd_to_linux_signal, 420 ELAST + 1, 421 bsd_to_linux_errno, 422 translate_traps, 423 elf_linux_fixup, 424 linux_sendsig, 425 linux_sigcode, 426 &linux_szsigcode, 427 linux_prepsyscall, 428 "Linux ELF", 429 elf_coredump 430 }; 431 432 static Elf32_Brandinfo linux_brand = { 433 "Linux", 434 "/compat/linux", 435 "/lib/ld-linux.so.1", 436 &elf_linux_sysvec 437 }; 438 439 static Elf32_Brandinfo linux_glibc2brand = { 440 "Linux", 441 "/compat/linux", 442 "/lib/ld-linux.so.2", 443 &elf_linux_sysvec 444 }; 445 446 Elf32_Brandinfo *linux_brandlist[] = { 447 &linux_brand, 448 &linux_glibc2brand, 449 NULL 450 }; 451 452 static int 453 linux_elf_modevent(module_t mod, int type, void *data) 454 { 455 Elf32_Brandinfo **brandinfo; 456 int error; 457 458 error = 0; 459 460 switch(type) { 461 case MOD_LOAD: 462 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 463 ++brandinfo) 464 if (elf_insert_brand_entry(*brandinfo) < 0) 465 error = EINVAL; 466 if (error) 467 printf("cannot insert Linux elf brand handler\n"); 468 else if (bootverbose) 469 printf("Linux-ELF exec handler installed\n"); 470 break; 471 case MOD_UNLOAD: 472 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 473 ++brandinfo) 474 if (elf_brand_inuse(*brandinfo)) { 475 error = EBUSY; 476 } 477 478 if (error == 0) { 479 for (brandinfo = &linux_brandlist[0]; 480 *brandinfo != NULL; ++brandinfo) 481 if (elf_remove_brand_entry(*brandinfo) < 0) 482 error = EINVAL; 483 } 484 if (error) 485 printf("Could not deinstall ELF interpreter entry\n"); 486 else if (bootverbose) 487 printf("Linux-elf exec handler removed\n"); 488 break; 489 default: 490 break; 491 } 492 return error; 493 } 494 static moduledata_t linux_elf_mod = { 495 "linuxelf", 496 linux_elf_modevent, 497 0 498 }; 499 DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 500