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 1.36 1998/10/11 21:08:02 alex 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] = { 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, -43, -42 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 if ((grow(p, (int)fp) == FALSE) || 221 (useracc((caddr_t)fp, sizeof (struct linux_sigframe), B_WRITE) == FALSE)) { 222 /* 223 * Process has trashed its stack; give it an illegal 224 * instruction to halt it in its tracks. 225 */ 226 SIGACTION(p, SIGILL) = SIG_DFL; 227 sig = sigmask(SIGILL); 228 p->p_sigignore &= ~sig; 229 p->p_sigcatch &= ~sig; 230 p->p_sigmask &= ~sig; 231 psignal(p, SIGILL); 232 return; 233 } 234 235 /* 236 * Build the argument list for the signal handler. 237 */ 238 if (p->p_sysent->sv_sigtbl) { 239 if (sig < p->p_sysent->sv_sigsize) 240 sig = p->p_sysent->sv_sigtbl[sig]; 241 else 242 sig = p->p_sysent->sv_sigsize + 1; 243 } 244 245 frame.sf_handler = catcher; 246 frame.sf_sig = sig; 247 248 /* 249 * Build the signal context to be used by sigreturn. 250 */ 251 frame.sf_sc.sc_mask = mask; 252 __asm("movl %%gs,%w0" : "=r" (frame.sf_sc.sc_gs)); 253 __asm("movl %%fs,%w0" : "=r" (frame.sf_sc.sc_fs)); 254 frame.sf_sc.sc_es = regs->tf_es; 255 frame.sf_sc.sc_ds = regs->tf_ds; 256 frame.sf_sc.sc_edi = regs->tf_edi; 257 frame.sf_sc.sc_esi = regs->tf_esi; 258 frame.sf_sc.sc_ebp = regs->tf_ebp; 259 frame.sf_sc.sc_ebx = regs->tf_ebx; 260 frame.sf_sc.sc_edx = regs->tf_edx; 261 frame.sf_sc.sc_ecx = regs->tf_ecx; 262 frame.sf_sc.sc_eax = regs->tf_eax; 263 frame.sf_sc.sc_eip = regs->tf_eip; 264 frame.sf_sc.sc_cs = regs->tf_cs; 265 frame.sf_sc.sc_eflags = regs->tf_eflags; 266 frame.sf_sc.sc_esp_at_signal = regs->tf_esp; 267 frame.sf_sc.sc_ss = regs->tf_ss; 268 frame.sf_sc.sc_err = regs->tf_err; 269 frame.sf_sc.sc_trapno = code; /* XXX ???? */ 270 271 if (copyout(&frame, fp, sizeof(frame)) != 0) { 272 /* 273 * Process has trashed its stack; give it an illegal 274 * instruction to halt it in its tracks. 275 */ 276 sigexit(p, SIGILL); 277 /* NOTREACHED */ 278 } 279 280 /* 281 * Build context to run handler in. 282 */ 283 regs->tf_esp = (int)fp; 284 regs->tf_eip = (int)(((char *)PS_STRINGS) - *(p->p_sysent->sv_szsigcode)); 285 regs->tf_eflags &= ~PSL_VM; 286 regs->tf_cs = _ucodesel; 287 regs->tf_ds = _udatasel; 288 regs->tf_es = _udatasel; 289 regs->tf_ss = _udatasel; 290 } 291 292 /* 293 * System call to cleanup state after a signal 294 * has been taken. Reset signal mask and 295 * stack state from context left by sendsig (above). 296 * Return to previous pc and psl as specified by 297 * context left by sendsig. Check carefully to 298 * make sure that the user has not modified the 299 * psl to gain improper privileges or to cause 300 * a machine fault. 301 */ 302 int 303 linux_sigreturn(p, args) 304 struct proc *p; 305 struct linux_sigreturn_args *args; 306 { 307 struct linux_sigcontext *scp, context; 308 register struct trapframe *regs; 309 int eflags; 310 311 regs = p->p_md.md_regs; 312 313 #ifdef DEBUG 314 printf("Linux-emul(%ld): linux_sigreturn(%p)\n", 315 (long)p->p_pid, (void *)args->scp); 316 #endif 317 /* 318 * The trampoline code hands us the context. 319 * It is unsafe to keep track of it ourselves, in the event that a 320 * program jumps out of a signal handler. 321 */ 322 scp = SCARG(args,scp); 323 if (copyin((caddr_t)scp, &context, sizeof(*scp)) != 0) 324 return (EFAULT); 325 326 /* 327 * Check for security violations. 328 */ 329 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) 330 eflags = context.sc_eflags; 331 /* 332 * XXX do allow users to change the privileged flag PSL_RF. The 333 * cpu sets PSL_RF in tf_eflags for faults. Debuggers should 334 * sometimes set it there too. tf_eflags is kept in the signal 335 * context during signal handling and there is no other place 336 * to remember it, so the PSL_RF bit may be corrupted by the 337 * signal handler without us knowing. Corruption of the PSL_RF 338 * bit at worst causes one more or one less debugger trap, so 339 * allowing it is fairly harmless. 340 */ 341 if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) { 342 return(EINVAL); 343 } 344 345 /* 346 * Don't allow users to load a valid privileged %cs. Let the 347 * hardware check for invalid selectors, excess privilege in 348 * other selectors, invalid %eip's and invalid %esp's. 349 */ 350 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) 351 if (!CS_SECURE(context.sc_cs)) { 352 trapsignal(p, SIGBUS, T_PROTFLT); 353 return(EINVAL); 354 } 355 356 p->p_sigacts->ps_sigstk.ss_flags &= ~SS_ONSTACK; 357 p->p_sigmask = context.sc_mask &~ 358 (sigmask(SIGKILL)|sigmask(SIGCONT)|sigmask(SIGSTOP)); 359 /* 360 * Restore signal context. 361 */ 362 /* %fs and %gs were restored by the trampoline. */ 363 regs->tf_es = context.sc_es; 364 regs->tf_ds = context.sc_ds; 365 regs->tf_edi = context.sc_edi; 366 regs->tf_esi = context.sc_esi; 367 regs->tf_ebp = context.sc_ebp; 368 regs->tf_ebx = context.sc_ebx; 369 regs->tf_edx = context.sc_edx; 370 regs->tf_ecx = context.sc_ecx; 371 regs->tf_eax = context.sc_eax; 372 regs->tf_eip = context.sc_eip; 373 regs->tf_cs = context.sc_cs; 374 regs->tf_eflags = eflags; 375 regs->tf_esp = context.sc_esp_at_signal; 376 regs->tf_ss = context.sc_ss; 377 378 return (EJUSTRETURN); 379 } 380 381 static void 382 linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params) 383 { 384 args[0] = tf->tf_ebx; 385 args[1] = tf->tf_ecx; 386 args[2] = tf->tf_edx; 387 args[3] = tf->tf_esi; 388 args[4] = tf->tf_edi; 389 *params = NULL; /* no copyin */ 390 } 391 392 struct sysentvec linux_sysvec = { 393 LINUX_SYS_MAXSYSCALL, 394 linux_sysent, 395 0xff, 396 NSIG, 397 bsd_to_linux_signal, 398 ELAST, 399 bsd_to_linux_errno, 400 translate_traps, 401 linux_fixup, 402 linux_sendsig, 403 linux_sigcode, 404 &linux_szsigcode, 405 linux_prepsyscall, 406 "Linux a.out", 407 aout_coredump 408 }; 409 410 struct sysentvec elf_linux_sysvec = { 411 LINUX_SYS_MAXSYSCALL, 412 linux_sysent, 413 0xff, 414 NSIG, 415 bsd_to_linux_signal, 416 ELAST, 417 bsd_to_linux_errno, 418 translate_traps, 419 elf_linux_fixup, 420 linux_sendsig, 421 linux_sigcode, 422 &linux_szsigcode, 423 linux_prepsyscall, 424 "Linux ELF", 425 elf_coredump 426 }; 427 428 /* 429 * Installed either via SYSINIT() or via LKM stubs. 430 */ 431 static Elf32_Brandinfo linux_brand = { 432 "Linux", 433 "/compat/linux", 434 "/lib/ld-linux.so.1", 435 &elf_linux_sysvec 436 }; 437 438 static Elf32_Brandinfo linux_glibc2brand = { 439 "Linux", 440 "/compat/linux", 441 "/lib/ld-linux.so.2", 442 &elf_linux_sysvec 443 }; 444 445 Elf32_Brandinfo *linux_brandlist[] = { 446 &linux_brand, 447 &linux_glibc2brand, 448 NULL 449 }; 450 451 /* 452 * XXX: this is WRONG, it needs to be SI_SUB_EXEC, but this is just at the 453 * "proof of concept" stage and will be fixed shortly 454 */ 455 static int linux_elf_modevent __P((module_t mod, modeventtype_t type, void *data)); 456 457 static int 458 linux_elf_modevent(module_t mod, modeventtype_t type, void *data) 459 { 460 Elf32_Brandinfo **brandinfo; 461 int error; 462 463 error = 0; 464 465 switch(type) { 466 case MOD_LOAD: 467 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 468 ++brandinfo) 469 if (elf_insert_brand_entry(*brandinfo) < 0) 470 error = EINVAL; 471 if (error) 472 printf("cannot insert Linux elf brand handler\n"); 473 else if (bootverbose) 474 printf("Linux-ELF exec handler installed\n"); 475 break; 476 case MOD_UNLOAD: 477 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; 478 ++brandinfo) 479 if (elf_remove_brand_entry(*brandinfo) < 0) 480 error = EINVAL; 481 if (error) 482 printf("Could not deinstall ELF interpreter entry\n"); 483 else if (bootverbose) 484 printf("Linux-elf exec handler removed\n"); 485 break; 486 default: 487 break; 488 } 489 return error; 490 } 491 static moduledata_t linux_elf_mod = { 492 "linuxelf", 493 linux_elf_modevent, 494 0 495 }; 496 DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY); 497