X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fsignal.c;h=c0afecc07c0c70a14e55380086a298ddd2c9b580;hb=refs%2Fheads%2Fvserver;hp=83cd4336af9f1910ad611f20122f6bbc6e0ed7e4;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/kernel/signal.c b/kernel/signal.c index 83cd4336a..c0afecc07 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -10,7 +10,6 @@ * to allow signals to be sent reliably. */ -#include #include #include #include @@ -21,22 +20,26 @@ #include #include #include -#include -#include +#include #include -#include #include -#include +#include +#include +#include +#include +#include + #include #include #include #include +#include "audit.h" /* audit_signal_info() */ /* * SLAB caches for signal bits. */ -static kmem_cache_t *sigqueue_cachep; +static struct kmem_cache *sigqueue_cachep; /* * In POSIX a signal is sent either to a specific thread (Linux task) @@ -148,6 +151,8 @@ static kmem_cache_t *sigqueue_cachep; #define sig_kernel_stop(sig) \ (((sig) < SIGRTMIN) && T(sig, SIG_KERNEL_STOP_MASK)) +#define sig_needs_tasklist(sig) ((sig) == SIGCONT) + #define sig_user_defined(t, signr) \ (((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) && \ ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN)) @@ -160,12 +165,6 @@ static int sig_ignored(struct task_struct *t, int sig) { void __user * handler; - /* - * Tracers always want to know about signals.. - */ - if (t->ptrace & PT_PTRACED) - return 0; - /* * Blocked signals are never ignored, since the * signal handler may change by the time it is @@ -176,8 +175,12 @@ static int sig_ignored(struct task_struct *t, int sig) /* Is it explicitly or implicitly ignored? */ handler = t->sighand->action[sig-1].sa.sa_handler; - return handler == SIG_IGN || - (handler == SIG_DFL && sig_kernel_ignore(sig)); + if (handler != SIG_IGN && + (handler != SIG_DFL || !sig_kernel_ignore(sig))) + return 0; + + /* It's ignored, we can short-circuit unless a debugger wants it. */ + return !tracehook_consider_ignored_signal(t, sig, handler); } /* @@ -217,7 +220,8 @@ fastcall void recalc_sigpending_tsk(struct task_struct *t) if (t->signal->group_stop_count > 0 || (freezing(t)) || PENDING(&t->pending, &t->blocked) || - PENDING(&t->signal->shared_pending, &t->blocked)) + PENDING(&t->signal->shared_pending, &t->blocked) || + tracehook_induce_sigpending(t)) set_tsk_thread_flag(t, TIF_SIGPENDING); else clear_tsk_thread_flag(t, TIF_SIGPENDING); @@ -268,18 +272,25 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, int override_rlimit) { struct sigqueue *q = NULL; + struct user_struct *user; - atomic_inc(&t->user->sigpending); + /* + * In order to avoid problems with "switch_user()", we want to make + * sure that the compiler doesn't re-load "t->user" + */ + user = t->user; + barrier(); + atomic_inc(&user->sigpending); if (override_rlimit || - atomic_read(&t->user->sigpending) <= + atomic_read(&user->sigpending) <= t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) q = kmem_cache_alloc(sigqueue_cachep, flags); if (unlikely(q == NULL)) { - atomic_dec(&t->user->sigpending); + atomic_dec(&user->sigpending); } else { INIT_LIST_HEAD(&q->list); q->flags = 0; - q->user = get_uid(t->user); + q->user = get_uid(user); } return(q); } @@ -293,7 +304,7 @@ static void __sigqueue_free(struct sigqueue *q) kmem_cache_free(sigqueue_cachep, q); } -static void flush_sigqueue(struct sigpending *queue) +void flush_sigqueue(struct sigpending *queue) { struct sigqueue *q; @@ -308,9 +319,7 @@ static void flush_sigqueue(struct sigpending *queue) /* * Flush all pending signals for a task. */ - -void -flush_signals(struct task_struct *t) +void flush_signals(struct task_struct *t) { unsigned long flags; @@ -321,109 +330,6 @@ flush_signals(struct task_struct *t) spin_unlock_irqrestore(&t->sighand->siglock, flags); } -/* - * This function expects the tasklist_lock write-locked. - */ -void __exit_sighand(struct task_struct *tsk) -{ - struct sighand_struct * sighand = tsk->sighand; - - /* Ok, we're done with the signal handlers */ - tsk->sighand = NULL; - if (atomic_dec_and_test(&sighand->count)) - sighand_free(sighand); -} - -void exit_sighand(struct task_struct *tsk) -{ - write_lock_irq(&tasklist_lock); - rcu_read_lock(); - if (tsk->sighand != NULL) { - struct sighand_struct *sighand = rcu_dereference(tsk->sighand); - spin_lock(&sighand->siglock); - __exit_sighand(tsk); - spin_unlock(&sighand->siglock); - } - rcu_read_unlock(); - write_unlock_irq(&tasklist_lock); -} - -/* - * This function expects the tasklist_lock write-locked. - */ -void __exit_signal(struct task_struct *tsk) -{ - struct signal_struct * sig = tsk->signal; - struct sighand_struct * sighand; - - if (!sig) - BUG(); - if (!atomic_read(&sig->count)) - BUG(); - rcu_read_lock(); - sighand = rcu_dereference(tsk->sighand); - spin_lock(&sighand->siglock); - posix_cpu_timers_exit(tsk); - if (atomic_dec_and_test(&sig->count)) { - posix_cpu_timers_exit_group(tsk); - tsk->signal = NULL; - __exit_sighand(tsk); - spin_unlock(&sighand->siglock); - flush_sigqueue(&sig->shared_pending); - } else { - /* - * If there is any task waiting for the group exit - * then notify it: - */ - if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) { - wake_up_process(sig->group_exit_task); - sig->group_exit_task = NULL; - } - if (tsk == sig->curr_target) - sig->curr_target = next_thread(tsk); - tsk->signal = NULL; - /* - * Accumulate here the counters for all threads but the - * group leader as they die, so they can be added into - * the process-wide totals when those are taken. - * The group leader stays around as a zombie as long - * as there are other threads. When it gets reaped, - * the exit.c code will add its counts into these totals. - * We won't ever get here for the group leader, since it - * will have been the last reference on the signal_struct. - */ - sig->utime = cputime_add(sig->utime, tsk->utime); - sig->stime = cputime_add(sig->stime, tsk->stime); - sig->min_flt += tsk->min_flt; - sig->maj_flt += tsk->maj_flt; - sig->nvcsw += tsk->nvcsw; - sig->nivcsw += tsk->nivcsw; - sig->sched_time += tsk->sched_time; - __exit_sighand(tsk); - spin_unlock(&sighand->siglock); - sig = NULL; /* Marker for below. */ - } - rcu_read_unlock(); - clear_tsk_thread_flag(tsk,TIF_SIGPENDING); - flush_sigqueue(&tsk->pending); - if (sig) { - /* - * We are cleaning up the signal_struct here. - */ - exit_thread_group_keys(sig); - kmem_cache_free(signal_cachep, sig); - } -} - -void exit_signal(struct task_struct *tsk) -{ - atomic_dec(&tsk->signal->live); - - write_lock_irq(&tasklist_lock); - __exit_signal(tsk); - write_unlock_irq(&tasklist_lock); -} - /* * Flush all handlers for a task. */ @@ -523,9 +429,8 @@ static int collect_signal(int sig, struct sigpending *list, siginfo_t *info) static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, siginfo_t *info) { - int sig = 0; + int sig = next_signal(pending, mask); - sig = next_signal(pending, mask); if (sig) { if (current->notifier) { if (sigismember(current->notifier_mask, sig)) { @@ -538,9 +443,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, if (!collect_signal(sig, pending, info)) sig = 0; - } - recalc_sigpending(); return sig; } @@ -557,6 +460,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) if (!signr) signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info); + recalc_sigpending_tsk(tsk); if (signr && unlikely(sig_kernel_stop(signr))) { /* * Set a marker that we have dequeued a stop signal. Our @@ -677,37 +581,41 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s) static int check_kill_permission(int sig, struct siginfo *info, struct task_struct *t) { - int user; int error = -EINVAL; if (!valid_signal(sig)) return error; - user = ((info == SEND_SIG_NOINFO) || - (!is_si_special(info) && SI_FROMUSER(info))); + if ((info != SEND_SIG_NOINFO) && + (is_si_special(info) || !SI_FROMUSER(info))) + goto skip; + + vxdprintk(VXD_CBIT(misc, 7), + "check_kill_permission(%d,%p,%p[#%u,%u])", + sig, info, t, vx_task_xid(t), t->pid); error = -EPERM; - if (user && ((sig != SIGCONT) || - (current->signal->session != t->signal->session)) + if (((sig != SIGCONT) || + (process_session(current) != process_session(t))) && (current->euid ^ t->suid) && (current->euid ^ t->uid) && (current->uid ^ t->suid) && (current->uid ^ t->uid) && !capable(CAP_KILL)) return error; error = -ESRCH; - if (user && !vx_check(vx_task_xid(t), VX_ADMIN|VX_IDENT)) + if (!vx_check(vx_task_xid(t), VS_WATCH_P|VS_IDENT)) { + vxdprintk(current->xid || VXD_CBIT(misc, 7), + "signal %d[%p] xid mismatch %p[#%u,%u] xid=#%u", + sig, info, t, vx_task_xid(t), t->pid, current->xid); return error; - - error = security_task_kill(t, info, sig); + } +skip: + error = security_task_kill(t, info, sig, 0); if (!error) audit_signal_info(sig, t); /* Let audit system see the signal */ return error; } -/* forward decl */ -static void do_notify_parent_cldstop(struct task_struct *tsk, - int to_self, - int why); /* * Handle magic process-wide effects of stop/continue signals. @@ -757,7 +665,7 @@ static void handle_stop_signal(int sig, struct task_struct *p) p->signal->group_stop_count = 0; p->signal->flags = SIGNAL_STOP_CONTINUED; spin_unlock(&p->sighand->siglock); - do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_STOPPED); + do_notify_parent_cldstop(p, CLD_STOPPED); spin_lock(&p->sighand->siglock); } rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); @@ -798,7 +706,7 @@ static void handle_stop_signal(int sig, struct task_struct *p) p->signal->flags = SIGNAL_STOP_CONTINUED; p->signal->group_exit_code = 0; spin_unlock(&p->sighand->siglock); - do_notify_parent_cldstop(p, (p->ptrace & PT_PTRACED), CLD_CONTINUED); + do_notify_parent_cldstop(p, CLD_CONTINUED); spin_lock(&p->sighand->siglock); } else { /* @@ -879,14 +787,44 @@ out_set: #define LEGACY_QUEUE(sigptr, sig) \ (((sig) < SIGRTMIN) && sigismember(&(sigptr)->signal, (sig))) +int print_fatal_signals = 0; + +static void print_fatal_signal(struct pt_regs *regs, int signr) +{ + printk("%s/%d: potentially unexpected fatal signal %d.\n", + current->comm, current->pid, signr); + +#ifdef __i386__ + printk("code at %08lx: ", regs->eip); + { + int i; + for (i = 0; i < 16; i++) { + unsigned char insn; + + __get_user(insn, (unsigned char *)(regs->eip + i)); + printk("%02x ", insn); + } + } +#endif + printk("\n"); + show_regs(regs); +} + +static int __init setup_print_fatal_signals(char *str) +{ + get_option (&str, &print_fatal_signals); + + return 1; +} + +__setup("print-fatal-signals=", setup_print_fatal_signals); static int specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) { int ret = 0; - if (!irqs_disabled()) - BUG(); + BUG_ON(!irqs_disabled()); assert_spin_locked(&t->sighand->siglock); /* Short-circuit ignored signals. */ @@ -909,22 +847,31 @@ out: /* * Force a signal that the process can't ignore: if necessary * we unblock the signal and change any SIG_IGN to SIG_DFL. + * + * Note: If we unblock the signal, we always reset it to SIG_DFL, + * since we do not want to have a signal handler that was blocked + * be invoked when user space had explicitly blocked it. + * + * We don't want to have recursive SIGSEGV's etc, for example. */ - int force_sig_info(int sig, struct siginfo *info, struct task_struct *t) { unsigned long int flags; - int ret; + int ret, blocked, ignored; + struct k_sigaction *action; spin_lock_irqsave(&t->sighand->siglock, flags); - if (t->sighand->action[sig-1].sa.sa_handler == SIG_IGN) { - t->sighand->action[sig-1].sa.sa_handler = SIG_DFL; - } - if (sigismember(&t->blocked, sig)) { - sigdelset(&t->blocked, sig); + action = &t->sighand->action[sig-1]; + ignored = action->sa.sa_handler == SIG_IGN; + blocked = sigismember(&t->blocked, sig); + if (blocked || ignored) { + action->sa.sa_handler = SIG_DFL; + if (blocked) { + sigdelset(&t->blocked, sig); + recalc_sigpending_tsk(t); + } } - recalc_sigpending_tsk(t); ret = specific_send_sig_info(sig, info, t); spin_unlock_irqrestore(&t->sighand->siglock, flags); @@ -1005,7 +952,7 @@ __group_complete_signal(int sig, struct task_struct *p) */ if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && !sigismember(&t->real_blocked, sig) && - (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { + (sig == SIGKILL || !tracehook_consider_fatal_signal(t, sig))) { /* * This signal will be fatal to the whole group. */ @@ -1129,55 +1076,81 @@ void zap_other_threads(struct task_struct *p) /* * Must be called under rcu_read_lock() or with tasklist_lock read-held. */ +struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) +{ + struct sighand_struct *sighand; + + for (;;) { + sighand = rcu_dereference(tsk->sighand); + if (unlikely(sighand == NULL)) + break; + + spin_lock_irqsave(&sighand->siglock, *flags); + if (likely(sighand == tsk->sighand)) + break; + spin_unlock_irqrestore(&sighand->siglock, *flags); + } + + return sighand; +} + int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) { unsigned long flags; - struct sighand_struct *sp; int ret; -retry: ret = check_kill_permission(sig, info, p); - if (!ret && sig && (sp = rcu_dereference(p->sighand))) { - spin_lock_irqsave(&sp->siglock, flags); - if (p->sighand != sp) { - spin_unlock_irqrestore(&sp->siglock, flags); - goto retry; - } - if ((atomic_read(&sp->count) == 0) || - (atomic_read(&p->usage) == 0)) { - spin_unlock_irqrestore(&sp->siglock, flags); - return -ESRCH; + + if (!ret && sig) { + ret = -ESRCH; + if (lock_task_sighand(p, &flags)) { + ret = __group_send_sig_info(sig, info, p); + unlock_task_sighand(p, &flags); } - ret = __group_send_sig_info(sig, info, p); - spin_unlock_irqrestore(&sp->siglock, flags); } return ret; } /* - * kill_pg_info() sends a signal to a process group: this is what the tty + * kill_pgrp_info() sends a signal to a process group: this is what the tty * control characters do (^C, ^Z etc) */ -int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) +int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) { struct task_struct *p = NULL; int retval, success; - if (pgrp <= 0) - return -EINVAL; - success = 0; retval = -ESRCH; - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { int err = group_send_sig_info(sig, info, p); success |= !err; retval = err; - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); return success ? 0 : retval; } +int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) +{ + int retval; + + read_lock(&tasklist_lock); + retval = __kill_pgrp_info(sig, info, pgrp); + read_unlock(&tasklist_lock); + + return retval; +} + +int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) +{ + if (pgrp <= 0) + return -EINVAL; + + return __kill_pgrp_info(sig, info, find_pid(pgrp)); +} + int kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) { @@ -1190,21 +1163,20 @@ kill_pg_info(int sig, struct siginfo *info, pid_t pgrp) return retval; } -int -kill_proc_info(int sig, struct siginfo *info, pid_t pid) +int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) { int error; int acquired_tasklist_lock = 0; struct task_struct *p; rcu_read_lock(); - if (unlikely(sig_kernel_stop(sig) || sig == SIGCONT)) { + if (unlikely(sig_needs_tasklist(sig))) { read_lock(&tasklist_lock); acquired_tasklist_lock = 1; } - p = find_task_by_pid(pid); + p = pid_task(pid, PIDTYPE_PID); error = -ESRCH; - if (p && vx_check(vx_task_xid(p), VX_IDENT)) + if (p && vx_check(vx_task_xid(p), VS_IDENT)) error = group_send_sig_info(sig, info, p); if (unlikely(acquired_tasklist_lock)) read_unlock(&tasklist_lock); @@ -1212,9 +1184,18 @@ kill_proc_info(int sig, struct siginfo *info, pid_t pid) return error; } -/* like kill_proc_info(), but doesn't use uid/euid of "current" */ -int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, - uid_t uid, uid_t euid) +static int kill_proc_info(int sig, struct siginfo *info, pid_t pid) +{ + int error; + rcu_read_lock(); + error = kill_pid_info(sig, info, find_pid(vx_rmap_pid(pid))); + rcu_read_unlock(); + return error; +} + +/* like kill_pid_info(), but doesn't use uid/euid of "current" */ +int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, + uid_t uid, uid_t euid, u32 secid) { int ret = -EINVAL; struct task_struct *p; @@ -1223,7 +1204,7 @@ int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, return ret; read_lock(&tasklist_lock); - p = find_task_by_pid(pid); + p = pid_task(pid, PIDTYPE_PID); if (!p) { ret = -ESRCH; goto out_unlock; @@ -1234,6 +1215,9 @@ int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid, ret = -EPERM; goto out_unlock; } + ret = security_task_kill(p, info, sig, secid); + if (ret) + goto out_unlock; if (sig && p->sighand) { unsigned long flags; spin_lock_irqsave(&p->sighand->siglock, flags); @@ -1244,7 +1228,7 @@ out_unlock: read_unlock(&tasklist_lock); return ret; } -EXPORT_SYMBOL_GPL(kill_proc_info_as_uid); +EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); /* * kill_something_info() interprets pid in interesting ways just like kill(2). @@ -1263,7 +1247,7 @@ static int kill_something_info(int sig, struct siginfo *info, int pid) read_lock(&tasklist_lock); for_each_process(p) { - if (vx_check(vx_task_xid(p), VX_ADMIN|VX_IDENT)&& + if (vx_check(vx_task_xid(p), VS_ADMIN_P|VS_IDENT) && p->pid > 1 && p->tgid != current->tgid) { int err = group_send_sig_info(sig, info, p); ++count; @@ -1363,6 +1347,18 @@ force_sigsegv(int sig, struct task_struct *p) return 0; } +int kill_pgrp(struct pid *pid, int sig, int priv) +{ + return kill_pgrp_info(sig, __si_special(priv), pid); +} +EXPORT_SYMBOL(kill_pgrp); + +int kill_pid(struct pid *pid, int sig, int priv) +{ + return kill_pid_info(sig, __si_special(priv), pid); +} +EXPORT_SYMBOL(kill_pid); + int kill_pg(pid_t pgrp, int sig, int priv) { @@ -1415,12 +1411,10 @@ void sigqueue_free(struct sigqueue *q) __sigqueue_free(q); } -int -send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) +int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) { unsigned long flags; int ret = 0; - struct sighand_struct *sh; BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); @@ -1434,48 +1428,17 @@ send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) */ rcu_read_lock(); - if (unlikely(p->flags & PF_EXITING)) { + if (!likely(lock_task_sighand(p, &flags))) { ret = -1; goto out_err; } -retry: - sh = rcu_dereference(p->sighand); - - spin_lock_irqsave(&sh->siglock, flags); - if (p->sighand != sh) { - /* We raced with exec() in a multithreaded process... */ - spin_unlock_irqrestore(&sh->siglock, flags); - goto retry; - } - - /* - * We do the check here again to handle the following scenario: - * - * CPU 0 CPU 1 - * send_sigqueue - * check PF_EXITING - * interrupt exit code running - * __exit_signal - * lock sighand->siglock - * unlock sighand->siglock - * lock sh->siglock - * add(tsk->pending) flush_sigqueue(tsk->pending) - * - */ - - if (unlikely(p->flags & PF_EXITING)) { - ret = -1; - goto out; - } - if (unlikely(!list_empty(&q->list))) { /* * If an SI_TIMER entry is already queue just increment * the overrun count. */ - if (q->info.si_code != SI_TIMER) - BUG(); + BUG_ON(q->info.si_code != SI_TIMER); q->info.si_overrun++; goto out; } @@ -1491,7 +1454,7 @@ retry: signal_wake_up(p, sig == SIGKILL); out: - spin_unlock_irqrestore(&sh->siglock, flags); + unlock_task_sighand(p, &flags); out_err: rcu_read_unlock(); @@ -1523,8 +1486,7 @@ send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) * the overrun count. Other uses should not try to * send the signal multiple times. */ - if (q->info.si_code != SI_TIMER) - BUG(); + BUG_ON(q->info.si_code != SI_TIMER); q->info.si_overrun++; goto out; } @@ -1569,8 +1531,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) /* do_notify_parent_cldstop should have been called instead. */ BUG_ON(tsk->state & (TASK_STOPPED|TASK_TRACED)); - BUG_ON(!tsk->ptrace && - (tsk->group_leader != tsk || !thread_group_empty(tsk))); + BUG_ON(tsk->group_leader != tsk || !thread_group_empty(tsk)); info.si_signo = sig; info.si_errno = 0; @@ -1595,7 +1556,7 @@ void do_notify_parent(struct task_struct *tsk, int sig) psig = tsk->parent->sighand; spin_lock_irqsave(&psig->siglock, flags); - if (!tsk->ptrace && sig == SIGCHLD && + if (sig == SIGCHLD && (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { /* @@ -1623,20 +1584,13 @@ void do_notify_parent(struct task_struct *tsk, int sig) spin_unlock_irqrestore(&psig->siglock, flags); } -static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int why) +void do_notify_parent_cldstop(struct task_struct *tsk, int why) { struct siginfo info; unsigned long flags; struct task_struct *parent; struct sighand_struct *sighand; - if (to_self) - parent = tsk->parent; - else { - tsk = tsk->group_leader; - parent = tsk->real_parent; - } - info.si_signo = SIGCHLD; info.si_errno = 0; info.si_pid = tsk->pid; @@ -1661,6 +1615,15 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int w BUG(); } + /* + * Tracing can decide that we should not do the normal notification. + */ + if (tracehook_notify_cldstop(tsk, &info)) + return; + + tsk = tsk->group_leader; + parent = tsk->parent; + sighand = parent->sighand; spin_lock_irqsave(&sighand->siglock, flags); if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && @@ -1673,108 +1636,23 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int to_self, int w spin_unlock_irqrestore(&sighand->siglock, flags); } -/* - * This must be called with current->sighand->siglock held. - * - * This should be the path for all ptrace stops. - * We always set current->last_siginfo while stopped here. - * That makes it a way to test a stopped process for - * being ptrace-stopped vs being job-control-stopped. - * - * If we actually decide not to stop at all because the tracer is gone, - * we leave nostop_code in current->exit_code. - */ -static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) -{ - /* - * If there is a group stop in progress, - * we must participate in the bookkeeping. - */ - if (current->signal->group_stop_count > 0) - --current->signal->group_stop_count; - - current->last_siginfo = info; - current->exit_code = exit_code; - - /* Let the debugger run. */ - set_current_state(TASK_TRACED); - spin_unlock_irq(¤t->sighand->siglock); - try_to_freeze(); - read_lock(&tasklist_lock); - if (likely(current->ptrace & PT_PTRACED) && - likely(current->parent != current->real_parent || - !(current->ptrace & PT_ATTACHED)) && - (likely(current->parent->signal != current->signal) || - !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) { - do_notify_parent_cldstop(current, 1, CLD_TRAPPED); - read_unlock(&tasklist_lock); - schedule(); - } else { - /* - * By the time we got the lock, our tracer went away. - * Don't stop here. - */ - read_unlock(&tasklist_lock); - set_current_state(TASK_RUNNING); - current->exit_code = nostop_code; - } - - /* - * We are back. Now reacquire the siglock before touching - * last_siginfo, so that we are sure to have synchronized with - * any signal-sending on another CPU that wants to examine it. - */ - spin_lock_irq(¤t->sighand->siglock); - current->last_siginfo = NULL; - - /* - * Queued signals ignored us while we were stopped for tracing. - * So check for any that we should take before resuming user mode. - */ - recalc_sigpending(); -} - -void ptrace_notify(int exit_code) -{ - siginfo_t info; - - BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); - - memset(&info, 0, sizeof info); - info.si_signo = SIGTRAP; - info.si_code = exit_code; - info.si_pid = current->pid; - info.si_uid = current->uid; - - /* Let the debugger run. */ - spin_lock_irq(¤t->sighand->siglock); - ptrace_stop(exit_code, 0, &info); - spin_unlock_irq(¤t->sighand->siglock); -} - static void finish_stop(int stop_count) { - int to_self; - /* * If there are no other threads in the group, or if there is * a group stop in progress and we are the last to stop, * report to the parent. When ptraced, every thread reports itself. */ - if (stop_count < 0 || (current->ptrace & PT_PTRACED)) - to_self = 1; - else if (stop_count == 0) - to_self = 0; - else - goto out; - - read_lock(&tasklist_lock); - do_notify_parent_cldstop(current, to_self, CLD_STOPPED); - read_unlock(&tasklist_lock); + if (!tracehook_finish_stop(stop_count <= 0) && stop_count <= 0) { + read_lock(&tasklist_lock); + do_notify_parent_cldstop(current, CLD_STOPPED); + read_unlock(&tasklist_lock); + } -out: - schedule(); + do { + schedule(); + } while (try_to_freeze()); /* * Now we don't run again until continued. */ @@ -1787,12 +1665,10 @@ out: * Returns nonzero if we've actually stopped and released the siglock. * Returns zero if we didn't stop and still hold the siglock. */ -static int -do_signal_stop(int signr) +static int do_signal_stop(int signr) { struct signal_struct *sig = current->signal; - struct sighand_struct *sighand = current->sighand; - int stop_count = -1; + int stop_count; if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) return 0; @@ -1802,86 +1678,37 @@ do_signal_stop(int signr) * There is a group stop in progress. We don't need to * start another one. */ - signr = sig->group_exit_code; stop_count = --sig->group_stop_count; - current->exit_code = signr; - set_current_state(TASK_STOPPED); - if (stop_count == 0) - sig->flags = SIGNAL_STOP_STOPPED; - spin_unlock_irq(&sighand->siglock); - } - else if (thread_group_empty(current)) { - /* - * Lock must be held through transition to stopped state. - */ - current->exit_code = current->signal->group_exit_code = signr; - set_current_state(TASK_STOPPED); - sig->flags = SIGNAL_STOP_STOPPED; - spin_unlock_irq(&sighand->siglock); - } - else { + } else { /* * There is no group stop already in progress. - * We must initiate one now, but that requires - * dropping siglock to get both the tasklist lock - * and siglock again in the proper order. Note that - * this allows an intervening SIGCONT to be posted. - * We need to check for that and bail out if necessary. + * We must initiate one now. */ struct task_struct *t; - spin_unlock_irq(&sighand->siglock); - - /* signals can be posted during this window */ - - read_lock(&tasklist_lock); - spin_lock_irq(&sighand->siglock); + sig->group_exit_code = signr; - if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED)) { + stop_count = 0; + for (t = next_thread(current); t != current; t = next_thread(t)) /* - * Another stop or continue happened while we - * didn't have the lock. We can just swallow this - * signal now. If we raced with a SIGCONT, that - * should have just cleared it now. If we raced - * with another processor delivering a stop signal, - * then the SIGCONT that wakes us up should clear it. + * Setting state to TASK_STOPPED for a group + * stop is always done with the siglock held, + * so this check has no races. */ - read_unlock(&tasklist_lock); - return 0; - } - - if (sig->group_stop_count == 0) { - sig->group_exit_code = signr; - stop_count = 0; - for (t = next_thread(current); t != current; - t = next_thread(t)) - /* - * Setting state to TASK_STOPPED for a group - * stop is always done with the siglock held, - * so this check has no races. - */ - if (!t->exit_state && - !(t->state & (TASK_STOPPED|TASK_TRACED))) { - stop_count++; - signal_wake_up(t, 0); - } - sig->group_stop_count = stop_count; - } - else { - /* A race with another thread while unlocked. */ - signr = sig->group_exit_code; - stop_count = --sig->group_stop_count; - } - - current->exit_code = signr; - set_current_state(TASK_STOPPED); - if (stop_count == 0) - sig->flags = SIGNAL_STOP_STOPPED; - - spin_unlock_irq(&sighand->siglock); - read_unlock(&tasklist_lock); + if (!t->exit_state && + !(t->state & (TASK_STOPPED|TASK_TRACED))) { + stop_count++; + signal_wake_up(t, 0); + } + sig->group_stop_count = stop_count; } + if (stop_count == 0) + sig->flags = SIGNAL_STOP_STOPPED; + current->exit_code = sig->group_exit_code; + __set_current_state(TASK_STOPPED); + + spin_unlock_irq(¤t->sighand->siglock); finish_stop(stop_count); return 1; } @@ -1933,6 +1760,8 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, sigset_t *mask = ¤t->blocked; int signr = 0; + try_to_freeze(); + relock: spin_lock_irq(¤t->sighand->siglock); for (;;) { @@ -1942,44 +1771,24 @@ relock: handle_group_stop()) goto relock; - signr = dequeue_signal(current, mask, info); - - if (!signr) - break; /* will return 0 */ - - if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { - ptrace_signal_deliver(regs, cookie); - - /* Let the debugger run. */ - ptrace_stop(signr, signr, info); - - /* We're back. Did the debugger cancel the sig? */ - signr = current->exit_code; - if (signr == 0) - continue; - - current->exit_code = 0; - - /* Update the siginfo structure if the signal has - changed. If the debugger wanted something - specific in the siginfo structure then it should - have updated *info via PTRACE_SETSIGINFO. */ - if (signr != info->si_signo) { - info->si_signo = signr; - info->si_errno = 0; - info->si_code = SI_USER; - info->si_pid = current->parent->pid; - info->si_uid = current->parent->uid; - } + /* + * Tracing can induce an artifical signal and choose sigaction. + * The return value in signr determines the default action, + * but info->si_signo is the signal number we will report. + */ + signr = tracehook_get_signal(current, regs, info, return_ka); + if (unlikely(signr < 0)) + goto relock; + if (unlikely(signr != 0)) + ka = return_ka; + else { + signr = dequeue_signal(current, mask, info); - /* If the (new) signal is now blocked, requeue it. */ - if (sigismember(¤t->blocked, signr)) { - specific_send_sig_info(signr, info, current); - continue; - } + if (!signr) + break; /* will return 0 */ + ka = ¤t->sighand->action[signr-1]; } - ka = ¤t->sighand->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ continue; if (ka->sa.sa_handler != SIG_DFL) { @@ -1998,8 +1807,12 @@ relock: if (sig_kernel_ignore(signr)) /* Default is nothing. */ continue; - /* Init gets no signals it doesn't want. */ - if (current->pid == 1) + /* + * Init of a pid space gets no signals it doesn't want from + * within that pid space. It can of course get signals from + * its parent pid space. + */ + if (current == child_reaper(current)) continue; /* virtual init is protected against user signals */ @@ -2029,7 +1842,7 @@ relock: spin_lock_irq(¤t->sighand->siglock); } - if (likely(do_signal_stop(signr))) { + if (likely(do_signal_stop(info->si_signo))) { /* It released the siglock. */ goto relock; } @@ -2047,6 +1860,8 @@ relock: * Anything else is fatal, maybe with a core dump. */ current->flags |= PF_SIGNALED; + if (print_fatal_signals) + print_fatal_signal(regs, signr); if (sig_kernel_coredump(signr)) { /* * If it was able to dump core, this kills all @@ -2056,13 +1871,13 @@ relock: * first and our do_group_exit call below will use * that value and ignore the one we pass it. */ - do_coredump((long)signr, signr, regs); + do_coredump(info->si_signo, info->si_signo, regs); } /* * Death signals, no core dump. */ - do_group_exit(signr); + do_group_exit(info->si_signo); /* NOTREACHED */ } spin_unlock_irq(¤t->sighand->siglock); @@ -2075,7 +1890,6 @@ EXPORT_SYMBOL(flush_signals); EXPORT_SYMBOL(force_sig); EXPORT_SYMBOL(kill_pg); EXPORT_SYMBOL(kill_proc); -EXPORT_SYMBOL(ptrace_notify); EXPORT_SYMBOL(send_sig); EXPORT_SYMBOL(send_sig_info); EXPORT_SYMBOL(sigprocmask); @@ -2115,10 +1929,11 @@ long do_no_restart_syscall(struct restart_block *param) int sigprocmask(int how, sigset_t *set, sigset_t *oldset) { int error; - sigset_t old_block; spin_lock_irq(¤t->sighand->siglock); - old_block = current->blocked; + if (oldset) + *oldset = current->blocked; + error = 0; switch (how) { case SIG_BLOCK: @@ -2135,8 +1950,7 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset) } recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - if (oldset) - *oldset = old_block; + return error; } @@ -2323,7 +2137,6 @@ sys_rt_sigtimedwait(const sigset_t __user *uthese, timeout = schedule_timeout_interruptible(timeout); - try_to_freeze(); spin_lock_irq(¤t->sighand->siglock); sig = dequeue_signal(current, &these, &info); current->blocked = current->real_blocked; @@ -2445,8 +2258,7 @@ sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) return kill_proc_info(sig, &info, pid); } -int -do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) +int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) { struct k_sigaction *k; sigset_t mask; @@ -2472,6 +2284,7 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) if (act) { sigdelsetmask(&act->sa.sa_mask, sigmask(SIGKILL) | sigmask(SIGSTOP)); + *k = *act; /* * POSIX 3.3.1.3: * "Setting a signal action to SIG_IGN for a signal that is @@ -2484,19 +2297,8 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) * be discarded, whether or not it is blocked" */ if (act->sa.sa_handler == SIG_IGN || - (act->sa.sa_handler == SIG_DFL && - sig_kernel_ignore(sig))) { - /* - * This is a fairly rare case, so we only take the - * tasklist_lock once we're sure we'll need it. - * Now we must do this little unlock and relock - * dance to maintain the lock hierarchy. - */ + (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) { struct task_struct *t = current; - spin_unlock_irq(&t->sighand->siglock); - read_lock(&tasklist_lock); - spin_lock_irq(&t->sighand->siglock); - *k = *act; sigemptyset(&mask); sigaddset(&mask, sig); rm_from_queue_full(&mask, &t->signal->shared_pending); @@ -2505,12 +2307,7 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) recalc_sigpending_tsk(t); t = next_thread(t); } while (t != current); - spin_unlock_irq(¤t->sighand->siglock); - read_unlock(&tasklist_lock); - return 0; } - - *k = *act; } spin_unlock_irq(¤t->sighand->siglock); @@ -2762,6 +2559,11 @@ asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) } #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ +__attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) +{ + return NULL; +} + void __init signals_init(void) { sigqueue_cachep =