arch/i386/kernel/signal.c

   1 /*
   2  *  linux/arch/i386/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   7  *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/smp.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/kernel.h>
  15 #include <linux/signal.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/unistd.h>
  20 #include <linux/stddef.h>
  21 #include <asm/ucontext.h>
  22 #include <asm/uaccess.h>
  23 #include <asm/i387.h>
  24
  25 #define DEBUG_SIG 0
  26
  27 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  28
  29 asmlinkage int sys_wait4(pid_t pid, unsigned long *stat_addr,
  30                          int options, unsigned long *ru);
  31 asmlinkage int FASTCALL(do_signal(struct pt_regs *regs, sigset_t *oldset));
  32
  33 int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
  34 {
  35         if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
  36                 return -EFAULT;
  37         if (from->si_code < 0)
  38                 return __copy_to_user(to, from, sizeof(siginfo_t));
  39         else {
  40                 int err;
  41
  42                 /* If you change siginfo_t structure, please be sure
  43                    this code is fixed accordingly.
  44                    It should never copy any pad contained in the structure
  45                    to avoid security leaks, but must copy the generic
  46                    3 ints plus the relevant union member.  */
  47                 err = __put_user(from->si_signo, &to->si_signo);
  48                 err |= __put_user(from->si_errno, &to->si_errno);
  49                 err |= __put_user((short)from->si_code, &to->si_code);
  50                 /* First 32bits of unions are always present.  */
  51                 err |= __put_user(from->si_pid, &to->si_pid);
  52                 switch (from->si_code >> 16) {
  53                 case __SI_FAULT >> 16:
  54                         break;
  55                 case __SI_CHLD >> 16:
  56                         err |= __put_user(from->si_utime, &to->si_utime);
  57                         err |= __put_user(from->si_stime, &to->si_stime);
  58                         err |= __put_user(from->si_status, &to->si_status);
  59                 default:
  60                         err |= __put_user(from->si_uid, &to->si_uid);
  61                         break;
  62                 /* case __SI_RT: This is not generated by the kernel as of now.  */
  63                 }
  64                 return err;
  65         }
  66 }
  67
  68 /*
  69  * Atomically swap in the new signal mask, and wait for a signal.
  70  */
  71 asmlinkage int
  72 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  73 {
  74         struct pt_regs * regs = (struct pt_regs *) &history0;
  75         sigset_t saveset;
  76
  77         mask &= _BLOCKABLE;
  78         spin_lock_irq(&current->sigmask_lock);
  79         saveset = current->blocked;
  80         siginitset(&current->blocked, mask);
  81         recalc_sigpending(current);
  82         spin_unlock_irq(&current->sigmask_lock);
  83
  84         regs->eax = -EINTR;
  85         while (1) {
  86                 current->state = TASK_INTERRUPTIBLE;
  87                 schedule();
  88                 if (do_signal(regs, &saveset))
  89                         return -EINTR;
  90         }
  91 }
  92
  93 asmlinkage int
  94 sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize)
  95 {
  96         struct pt_regs * regs = (struct pt_regs *) &unewset;
  97         sigset_t saveset, newset;
  98
  99         /* XXX: Don't preclude handling different sized sigset_t's.  */
 100         if (sigsetsize != sizeof(sigset_t))
 101                 return -EINVAL;
 102
 103         if (copy_from_user(&newset, unewset, sizeof(newset)))
 104                 return -EFAULT;
 105         sigdelsetmask(&newset, ~_BLOCKABLE);
 106
 107         spin_lock_irq(&current->sigmask_lock);
 108         saveset = current->blocked;
 109         current->blocked = newset;
 110         recalc_sigpending(current);
 111         spin_unlock_irq(&current->sigmask_lock);
 112
 113         regs->eax = -EINTR;
 114         while (1) {
 115                 current->state = TASK_INTERRUPTIBLE;
 116                 schedule();
 117                 if (do_signal(regs, &saveset))
 118                         return -EINTR;
 119         }
 120 }
 121
 122 asmlinkage int
 123 sys_sigaction(int sig, const struct old_sigaction *act,
 124               struct old_sigaction *oact)
 125 {
 126         struct k_sigaction new_ka, old_ka;
 127         int ret;
 128
 129         if (act) {
 130                 old_sigset_t mask;
 131                 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
 132                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 133                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 134                         return -EFAULT;
 135                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 136                 __get_user(mask, &act->sa_mask);
 137                 siginitset(&new_ka.sa.sa_mask, mask);
 138         }
 139
 140         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 141
 142         if (!ret && oact) {
 143                 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
 144                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 145                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 146                         return -EFAULT;
 147                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 148                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 149         }
 150
 151         return ret;
 152 }
 153
 154 asmlinkage int
 155 sys_sigaltstack(const stack_t *uss, stack_t *uoss)
 156 {
 157         struct pt_regs *regs = (struct pt_regs *) &uss;
 158         return do_sigaltstack(uss, uoss, regs->esp);
 159 }
 160
 161
 162 /*
 163  * Do a signal return; undo the signal stack.
 164  */
 165
 166 struct sigframe
 167 {
 168         char *pretcode;
 169         int sig;
 170         struct sigcontext sc;
 171         struct _fpstate fpstate;
 172         unsigned long extramask[_NSIG_WORDS-1];
 173         char retcode[8];
 174 };
 175
 176 struct rt_sigframe
 177 {
 178         char *pretcode;
 179         int sig;
 180         struct siginfo *pinfo;
 181         void *puc;
 182         struct siginfo info;
 183         struct ucontext uc;
 184         struct _fpstate fpstate;
 185         char retcode[8];
 186 };
 187
 188 static int
 189 restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *peax)
 190 {
 191         unsigned int err = 0;
 192
 193 #define COPY(x)         err |= __get_user(regs->x, &sc->x)
 194
 195 #define COPY_SEG(seg)                                                   \
 196         { unsigned short tmp;                                           \
 197           err |= __get_user(tmp, &sc->seg);                             \
 198           regs->x##seg = tmp; }
 199
 200 #define COPY_SEG_STRICT(seg)                                            \
 201         { unsigned short tmp;                                           \
 202           err |= __get_user(tmp, &sc->seg);                             \
 203           regs->x##seg = tmp|3; }
 204
 205 #define GET_SEG(seg)                                                    \
 206         { unsigned short tmp;                                           \
 207           err |= __get_user(tmp, &sc->seg);                             \
 208           loadsegment(seg,tmp); }
 209
 210         GET_SEG(gs);
 211         GET_SEG(fs);
 212         COPY_SEG(es);
 213         COPY_SEG(ds);
 214         COPY(edi);
 215         COPY(esi);
 216         COPY(ebp);
 217         COPY(esp);
 218         COPY(ebx);
 219         COPY(edx);
 220         COPY(ecx);
 221         COPY(eip);
 222         COPY_SEG_STRICT(cs);
 223         COPY_SEG_STRICT(ss);
 224
 225         {
 226                 unsigned int tmpflags;
 227                 err |= __get_user(tmpflags, &sc->eflags);
 228                 regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
 229                 regs->orig_eax = -1;            /* disable syscall checks */
 230         }
 231
 232         {
 233                 struct _fpstate * buf;
 234                 err |= __get_user(buf, &sc->fpstate);
 235                 if (buf) {
 236                         if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
 237                                 goto badframe;
 238                         err |= restore_i387(buf);
 239                 }
 240         }
 241
 242         err |= __get_user(*peax, &sc->eax);
 243         return err;
 244
 245 badframe:
 246         return 1;
 247 }
 248
 249 asmlinkage int sys_sigreturn(unsigned long __unused)
 250 {
 251         struct pt_regs *regs = (struct pt_regs *) &__unused;
 252         struct sigframe *frame = (struct sigframe *)(regs->esp - 8);
 253         sigset_t set;
 254         int eax;
 255
 256         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 257                 goto badframe;
 258         if (__get_user(set.sig[0], &frame->sc.oldmask)
 259             || (_NSIG_WORDS > 1
 260                 && __copy_from_user(&set.sig[1], &frame->extramask,
 261                                     sizeof(frame->extramask))))
 262                 goto badframe;
 263
 264         sigdelsetmask(&set, ~_BLOCKABLE);
 265         spin_lock_irq(&current->sigmask_lock);
 266         current->blocked = set;
 267         recalc_sigpending(current);
 268         spin_unlock_irq(&current->sigmask_lock);
 269
 270         if (restore_sigcontext(regs, &frame->sc, &eax))
 271                 goto badframe;
 272         return eax;
 273
 274 badframe:
 275         force_sig(SIGSEGV, current);
 276         return 0;
 277 }
 278
 279 asmlinkage int sys_rt_sigreturn(unsigned long __unused)
 280 {
 281         struct pt_regs *regs = (struct pt_regs *) &__unused;
 282         struct rt_sigframe *frame = (struct rt_sigframe *)(regs->esp - 4);
 283         sigset_t set;
 284         stack_t st;
 285         int eax;
 286
 287         if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
 288                 goto badframe;
 289         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 290                 goto badframe;
 291
 292         sigdelsetmask(&set, ~_BLOCKABLE);
 293         spin_lock_irq(&current->sigmask_lock);
 294         current->blocked = set;
 295         recalc_sigpending(current);
 296         spin_unlock_irq(&current->sigmask_lock);
 297
 298         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
 299                 goto badframe;
 300
 301         if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
 302                 goto badframe;
 303         /* It is more difficult to avoid calling this function than to
 304            call it and ignore errors.  */
 305         do_sigaltstack(&st, NULL, regs->esp);
 306
 307         return eax;
 308
 309 badframe:
 310         force_sig(SIGSEGV, current);
 311         return 0;
 312 }
 313
 314 /*
 315  * Set up a signal frame.
 316  */
 317
 318 static int
 319 setup_sigcontext(struct sigcontext *sc, struct _fpstate *fpstate,
 320                  struct pt_regs *regs, unsigned long mask)
 321 {
 322         int tmp, err = 0;
 323
 324         tmp = 0;
 325         __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
 326         err |= __put_user(tmp, (unsigned int *)&sc->gs);
 327         __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
 328         err |= __put_user(tmp, (unsigned int *)&sc->fs);
 329
 330         err |= __put_user(regs->xes, (unsigned int *)&sc->es);
 331         err |= __put_user(regs->xds, (unsigned int *)&sc->ds);
 332         err |= __put_user(regs->edi, &sc->edi);
 333         err |= __put_user(regs->esi, &sc->esi);
 334         err |= __put_user(regs->ebp, &sc->ebp);
 335         err |= __put_user(regs->esp, &sc->esp);
 336         err |= __put_user(regs->ebx, &sc->ebx);
 337         err |= __put_user(regs->edx, &sc->edx);
 338         err |= __put_user(regs->ecx, &sc->ecx);
 339         err |= __put_user(regs->eax, &sc->eax);
 340         err |= __put_user(current->thread.trap_no, &sc->trapno);
 341         err |= __put_user(current->thread.error_code, &sc->err);
 342         err |= __put_user(regs->eip, &sc->eip);
 343         err |= __put_user(regs->xcs, (unsigned int *)&sc->cs);
 344         err |= __put_user(regs->eflags, &sc->eflags);
 345         err |= __put_user(regs->esp, &sc->esp_at_signal);
 346         err |= __put_user(regs->xss, (unsigned int *)&sc->ss);
 347
 348         tmp = save_i387(fpstate);
 349         if (tmp < 0)
 350           err = 1;
 351         else
 352           err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
 353
 354         /* non-iBCS2 extensions.. */
 355         err |= __put_user(mask, &sc->oldmask);
 356         err |= __put_user(current->thread.cr2, &sc->cr2);
 357
 358         return err;
 359 }
 360
 361 /*
 362  * Determine which stack to use..
 363  */
 364 static inline void *
 365 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 366 {
 367         unsigned long esp;
 368
 369         /* Default to using normal stack */
 370         esp = regs->esp;
 371
 372         /* This is the X/Open sanctioned signal stack switching.  */
 373         if (ka->sa.sa_flags & SA_ONSTACK) {
 374                 if (! on_sig_stack(esp))
 375                         esp = current->sas_ss_sp + current->sas_ss_size;
 376         }
 377
 378         /* This is the legacy signal stack switching. */
 379         else if ((regs->xss & 0xffff) != __USER_DS &&
 380                  !(ka->sa.sa_flags & SA_RESTORER) &&
 381                  ka->sa.sa_restorer) {
 382                 esp = (unsigned long) ka->sa.sa_restorer;
 383         }
 384
 385         return (void *)((esp - frame_size) & -8ul);
 386 }
 387
 388 static void setup_frame(int sig, struct k_sigaction *ka,
 389                         sigset_t *set, struct pt_regs * regs)
 390 {
 391         struct sigframe *frame;
 392         int err = 0;
 393
 394         frame = get_sigframe(ka, regs, sizeof(*frame));
 395
 396         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 397                 goto give_sigsegv;
 398
 399         err |= __put_user((current->exec_domain
 400                            && current->exec_domain->signal_invmap
 401                            && sig < 32
 402                            ? current->exec_domain->signal_invmap[sig]
 403                            : sig),
 404                           &frame->sig);
 405         if (err)
 406                 goto give_sigsegv;
 407
 408         err |= setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
 409         if (err)
 410                 goto give_sigsegv;
 411
 412         if (_NSIG_WORDS > 1) {
 413                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 414                                       sizeof(frame->extramask));
 415         }
 416         if (err)
 417                 goto give_sigsegv;
 418
 419         /* Set up to return from userspace.  If provided, use a stub
 420            already in userspace.  */
 421         if (ka->sa.sa_flags & SA_RESTORER) {
 422                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
 423         } else {
 424                 err |= __put_user(frame->retcode, &frame->pretcode);
 425                 /* This is popl %eax ; movl $,%eax ; int $0x80 */
 426                 err |= __put_user(0xb858, (short *)(frame->retcode+0));
 427                 err |= __put_user(__NR_sigreturn, (int *)(frame->retcode+2));
 428                 err |= __put_user(0x80cd, (short *)(frame->retcode+6));
 429         }
 430
 431         if (err)
 432                 goto give_sigsegv;
 433
 434         /* Set up registers for signal handler */
 435         regs->esp = (unsigned long) frame;
 436         regs->eip = (unsigned long) ka->sa.sa_handler;
 437
 438         set_fs(USER_DS);
 439         regs->xds = __USER_DS;
 440         regs->xes = __USER_DS;
 441         regs->xss = __USER_DS;
 442         regs->xcs = __USER_CS;
 443         regs->eflags &= ~TF_MASK;
 444
 445 #if DEBUG_SIG
 446         printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 447                 current->comm, current->pid, frame, regs->eip, frame->pretcode);
 448 #endif
 449
 450         return;
 451
 452 give_sigsegv:
 453         if (sig == SIGSEGV)
 454                 ka->sa.sa_handler = SIG_DFL;
 455         force_sig(SIGSEGV, current);
 456 }
 457
 458 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 459                            sigset_t *set, struct pt_regs * regs)
 460 {
 461         struct rt_sigframe *frame;
 462         int err = 0;
 463
 464         frame = get_sigframe(ka, regs, sizeof(*frame));
 465
 466         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 467                 goto give_sigsegv;
 468
 469         err |= __put_user((current->exec_domain
 470                            && current->exec_domain->signal_invmap
 471                            && sig < 32
 472                            ? current->exec_domain->signal_invmap[sig]
 473                            : sig),
 474                           &frame->sig);
 475         err |= __put_user(&frame->info, &frame->pinfo);
 476         err |= __put_user(&frame->uc, &frame->puc);
 477         err |= copy_siginfo_to_user(&frame->info, info);
 478         if (err)
 479                 goto give_sigsegv;
 480
 481         /* Create the ucontext.  */
 482         err |= __put_user(0, &frame->uc.uc_flags);
 483         err |= __put_user(0, &frame->uc.uc_link);
 484         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
 485         err |= __put_user(sas_ss_flags(regs->esp),
 486                           &frame->uc.uc_stack.ss_flags);
 487         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 488         err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
 489                                 regs, set->sig[0]);
 490         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 491         if (err)
 492                 goto give_sigsegv;
 493
 494         /* Set up to return from userspace.  If provided, use a stub
 495            already in userspace.  */
 496         if (ka->sa.sa_flags & SA_RESTORER) {
 497                 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
 498         } else {
 499                 err |= __put_user(frame->retcode, &frame->pretcode);
 500                 /* This is movl $,%eax ; int $0x80 */
 501                 err |= __put_user(0xb8, (char *)(frame->retcode+0));
 502                 err |= __put_user(__NR_rt_sigreturn, (int *)(frame->retcode+1));
 503                 err |= __put_user(0x80cd, (short *)(frame->retcode+5));
 504         }
 505
 506         if (err)
 507                 goto give_sigsegv;
 508
 509         /* Set up registers for signal handler */
 510         regs->esp = (unsigned long) frame;
 511         regs->eip = (unsigned long) ka->sa.sa_handler;
 512
 513         set_fs(USER_DS);
 514         regs->xds = __USER_DS;
 515         regs->xes = __USER_DS;
 516         regs->xss = __USER_DS;
 517         regs->xcs = __USER_CS;
 518         regs->eflags &= ~TF_MASK;
 519
 520 #if DEBUG_SIG
 521         printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 522                 current->comm, current->pid, frame, regs->eip, frame->pretcode);
 523 #endif
 524
 525         return;
 526
 527 give_sigsegv:
 528         if (sig == SIGSEGV)
 529                 ka->sa.sa_handler = SIG_DFL;
 530         force_sig(SIGSEGV, current);
 531 }
 532
 533 /*
 534  * OK, we're invoking a handler
 535  */
 536
 537 static void
 538 handle_signal(unsigned long sig, struct k_sigaction *ka,
 539               siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
 540 {
 541         /* Are we from a system call? */
 542         if (regs->orig_eax >= 0) {
 543                 /* If so, check system call restarting.. */
 544                 switch (regs->eax) {
 545                         case -ERESTARTNOHAND:
 546                                 regs->eax = -EINTR;
 547                                 break;
 548
 549                         case -ERESTARTSYS:
 550                                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 551                                         regs->eax = -EINTR;
 552                                         break;
 553                                 }
 554                         /* fallthrough */
 555                         case -ERESTARTNOINTR:
 556                                 regs->eax = regs->orig_eax;
 557                                 regs->eip -= 2;
 558                 }
 559         }
 560
 561         /* Set up the stack frame */
 562         if (ka->sa.sa_flags & SA_SIGINFO)
 563                 setup_rt_frame(sig, ka, info, oldset, regs);
 564         else
 565                 setup_frame(sig, ka, oldset, regs);
 566
 567         if (ka->sa.sa_flags & SA_ONESHOT)
 568                 ka->sa.sa_handler = SIG_DFL;
 569
 570         if (!(ka->sa.sa_flags & SA_NODEFER)) {
 571                 spin_lock_irq(&current->sigmask_lock);
 572                 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
 573                 sigaddset(&current->blocked,sig);
 574                 recalc_sigpending(current);
 575                 spin_unlock_irq(&current->sigmask_lock);
 576         }
 577 }
 578
 579 /*
 580  * Note that 'init' is a special process: it doesn't get signals it doesn't
 581  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 582  * mistake.
 583  */
 584 int do_signal(struct pt_regs *regs, sigset_t *oldset)
 585 {
 586         siginfo_t info;
 587         struct k_sigaction *ka;
 588
 589         /*
 590          * We want the common case to go fast, which
 591          * is why we may in certain cases get here from
 592          * kernel mode. Just return without doing anything
 593          * if so.
 594          */
 595         if ((regs->xcs & 3) != 3)
 596                 return 1;
 597
 598         if (!oldset)
 599                 oldset = &current->blocked;
 600
 601         for (;;) {
 602                 unsigned long signr;
 603
 604                 spin_lock_irq(&current->sigmask_lock);
 605                 signr = dequeue_signal(&current->blocked, &info);
 606                 spin_unlock_irq(&current->sigmask_lock);
 607
 608                 if (!signr)
 609                         break;
 610
 611                 if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
 612                         /* Let the debugger run.  */
 613                         current->exit_code = signr;
 614                         current->state = TASK_STOPPED;
 615                         notify_parent(current, SIGCHLD);
 616                         schedule();
 617
 618                         /* We're back.  Did the debugger cancel the sig?  */
 619                         if (!(signr = current->exit_code))
 620                                 continue;
 621                         current->exit_code = 0;
 622
 623                         /* The debugger continued.  Ignore SIGSTOP.  */
 624                         if (signr == SIGSTOP)
 625                                 continue;
 626
 627                         /* Update the siginfo structure.  Is this good?  */
 628                         if (signr != info.si_signo) {
 629                                 info.si_signo = signr;
 630                                 info.si_errno = 0;
 631                                 info.si_code = SI_USER;
 632                                 info.si_pid = current->p_pptr->pid;
 633                                 info.si_uid = current->p_pptr->uid;
 634                         }
 635
 636                         /* If the (new) signal is now blocked, requeue it.  */
 637                         if (sigismember(&current->blocked, signr)) {
 638                                 send_sig_info(signr, &info, current);
 639                                 continue;
 640                         }
 641                 }
 642
 643                 ka = &current->sig->action[signr-1];
 644                 if (ka->sa.sa_handler == SIG_IGN) {
 645                         if (signr != SIGCHLD)
 646                                 continue;
 647                         /* Check for SIGCHLD: it's special.  */
 648                         while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
 649                                 /* nothing */;
 650                         continue;
 651                 }
 652
 653                 if (ka->sa.sa_handler == SIG_DFL) {
 654                         int exit_code = signr;
 655
 656                         /* Init gets no signals it doesn't want.  */
 657                         if (current->pid == 1)
 658                                 continue;
 659
 660                         switch (signr) {
 661                         case SIGCONT: case SIGCHLD: case SIGWINCH:
 662                                 continue;
 663
 664                         case SIGTSTP: case SIGTTIN: case SIGTTOU:
 665                                 if (is_orphaned_pgrp(current->pgrp))
 666                                         continue;
 667                                 /* FALLTHRU */
 668
 669                         case SIGSTOP:
 670                                 current->state = TASK_STOPPED;
 671                                 current->exit_code = signr;
 672                                 if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
 673                                         notify_parent(current, SIGCHLD);
 674                                 schedule();
 675                                 continue;
 676
 677                         case SIGQUIT: case SIGILL: case SIGTRAP:
 678                         case SIGABRT: case SIGFPE: case SIGSEGV:
 679                         case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
 680                                 if (do_coredump(signr, regs))
 681                                         exit_code |= 0x80;
 682                                 /* FALLTHRU */
 683
 684                         default:
 685                                 sigaddset(&current->pending.signal, signr);
 686                                 recalc_sigpending(current);
 687                                 current->flags |= PF_SIGNALED;
 688                                 do_exit(exit_code);
 689                                 /* NOTREACHED */
 690                         }
 691                 }
 692
 693                 /* Reenable any watchpoints before delivering the
 694                  * signal to user space. The processor register will
 695                  * have been cleared if the watchpoint triggered
 696                  * inside the kernel.
 697                  */
 698                 __asm__("movl %0,%%db7" : : "r" (current->thread.debugreg[7]));
 699
 700                 /* Whee!  Actually deliver the signal.  */
 701                 handle_signal(signr, ka, &info, oldset, regs);
 702                 return 1;
 703         }
 704
 705         /* Did we come from a system call? */
 706         if (regs->orig_eax >= 0) {
 707                 /* Restart the system call - no handlers present */
 708                 if (regs->eax == -ERESTARTNOHAND ||
 709                     regs->eax == -ERESTARTSYS ||
 710                     regs->eax == -ERESTARTNOINTR) {
 711                         regs->eax = regs->orig_eax;
 712                         regs->eip -= 2;
 713                 }
 714         }
 715         return 0;
 716 }