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Jeff Dike1d3468a2006-07-10 04:45:13 -07001/*
Jeff Dikeba180fd2007-10-16 01:27:00 -07002 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * Licensed under the GPL
4 */
5
Jeff Dikec5d4bb12008-02-04 22:31:14 -08006#include <linux/module.h>
7#include <linux/ptrace.h>
8#include <linux/sched.h>
9#include <asm/siginfo.h>
10#include <asm/signal.h>
11#include <asm/unistd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include "frame_kern.h"
Jeff Dikeba180fd2007-10-16 01:27:00 -070013#include "kern_util.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include "sigcontext.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16EXPORT_SYMBOL(block_signals);
17EXPORT_SYMBOL(unblock_signals);
18
19#define _S(nr) (1<<((nr)-1))
20
21#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
22
23/*
24 * OK, we're invoking a handler
Jeff Dike1d3468a2006-07-10 04:45:13 -070025 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070026static int handle_signal(struct pt_regs *regs, unsigned long signr,
27 struct k_sigaction *ka, siginfo_t *info,
28 sigset_t *oldset)
29{
30 unsigned long sp;
31 int err;
32
33 /* Always make any pending restarted system calls return -EINTR */
34 current_thread_info()->restart_block.fn = do_no_restart_syscall;
35
36 /* Did we come from a system call? */
Jeff Dikeba180fd2007-10-16 01:27:00 -070037 if (PT_REGS_SYSCALL_NR(regs) >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 /* If so, check system call restarting.. */
Jeff Dikec5d4bb12008-02-04 22:31:14 -080039 switch (PT_REGS_SYSCALL_RET(regs)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 case -ERESTART_RESTARTBLOCK:
41 case -ERESTARTNOHAND:
42 PT_REGS_SYSCALL_RET(regs) = -EINTR;
43 break;
44
45 case -ERESTARTSYS:
46 if (!(ka->sa.sa_flags & SA_RESTART)) {
47 PT_REGS_SYSCALL_RET(regs) = -EINTR;
48 break;
49 }
50 /* fallthrough */
51 case -ERESTARTNOINTR:
52 PT_REGS_RESTART_SYSCALL(regs);
53 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
54 break;
55 }
56 }
57
58 sp = PT_REGS_SP(regs);
Jeff Dikeba180fd2007-10-16 01:27:00 -070059 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 sp = current->sas_ss_sp + current->sas_ss_size;
61
62#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
Jeff Dikeba180fd2007-10-16 01:27:00 -070063 if (!(ka->sa.sa_flags & SA_SIGINFO))
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
65 else
66#endif
67 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
68
Jeff Dikeba180fd2007-10-16 01:27:00 -070069 if (err) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 spin_lock_irq(&current->sighand->siglock);
71 current->blocked = *oldset;
72 recalc_sigpending();
73 spin_unlock_irq(&current->sighand->siglock);
74 force_sigsegv(signr, current);
Steven Rostedt69be8f12005-08-29 11:44:09 -040075 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 spin_lock_irq(&current->sighand->siglock);
Jeff Dike1d3468a2006-07-10 04:45:13 -070077 sigorsets(&current->blocked, &current->blocked,
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 &ka->sa.sa_mask);
Jeff Dikeba180fd2007-10-16 01:27:00 -070079 if (!(ka->sa.sa_flags & SA_NODEFER))
Steven Rostedt69be8f12005-08-29 11:44:09 -040080 sigaddset(&current->blocked, signr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 recalc_sigpending();
82 spin_unlock_irq(&current->sighand->siglock);
83 }
84
85 return err;
86}
87
Jeff Dike2fc10622006-01-18 17:44:02 -080088static int kern_do_signal(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070089{
90 struct k_sigaction ka_copy;
91 siginfo_t info;
Jeff Dike2fc10622006-01-18 17:44:02 -080092 sigset_t *oldset;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 int sig, handled_sig = 0;
94
Jeff Dike2fc10622006-01-18 17:44:02 -080095 if (test_thread_flag(TIF_RESTORE_SIGMASK))
96 oldset = &current->saved_sigmask;
97 else
98 oldset = &current->blocked;
99
Jeff Dikeba180fd2007-10-16 01:27:00 -0700100 while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 handled_sig = 1;
102 /* Whee! Actually deliver the signal. */
Jeff Dikeba180fd2007-10-16 01:27:00 -0700103 if (!handle_signal(regs, sig, &ka_copy, &info, oldset)) {
104 /*
105 * a signal was successfully delivered; the saved
Jeff Dike2fc10622006-01-18 17:44:02 -0800106 * sigmask will have been stored in the signal frame,
107 * and will be restored by sigreturn, so we can simply
Jeff Dikeba180fd2007-10-16 01:27:00 -0700108 * clear the TIF_RESTORE_SIGMASK flag
109 */
Jeff Dike2fc10622006-01-18 17:44:02 -0800110 if (test_thread_flag(TIF_RESTORE_SIGMASK))
111 clear_thread_flag(TIF_RESTORE_SIGMASK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 break;
Jeff Dike2fc10622006-01-18 17:44:02 -0800113 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 }
115
116 /* Did we come from a system call? */
Jeff Dikeba180fd2007-10-16 01:27:00 -0700117 if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 /* Restart the system call - no handlers present */
Jeff Dikec5d4bb12008-02-04 22:31:14 -0800119 switch (PT_REGS_SYSCALL_RET(regs)) {
Jeff Dike2fc10622006-01-18 17:44:02 -0800120 case -ERESTARTNOHAND:
121 case -ERESTARTSYS:
122 case -ERESTARTNOINTR:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
124 PT_REGS_RESTART_SYSCALL(regs);
Jeff Dike2fc10622006-01-18 17:44:02 -0800125 break;
126 case -ERESTART_RESTARTBLOCK:
Jeff Dike1d3468a2006-07-10 04:45:13 -0700127 PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 PT_REGS_RESTART_SYSCALL(regs);
Jeff Dike2fc10622006-01-18 17:44:02 -0800129 break;
Jeff Dikeba180fd2007-10-16 01:27:00 -0700130 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 }
132
Jeff Dikeba180fd2007-10-16 01:27:00 -0700133 /*
134 * This closes a way to execute a system call on the host. If
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 * you set a breakpoint on a system call instruction and singlestep
136 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
137 * rather than PTRACE_SYSCALL it, allowing the system call to execute
Jeff Dike1d3468a2006-07-10 04:45:13 -0700138 * on the host. The tracing thread will check this flag and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 * PTRACE_SYSCALL if necessary.
140 */
Jeff Dikeba180fd2007-10-16 01:27:00 -0700141 if (current->ptrace & PT_DTRACE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 current->thread.singlestep_syscall =
143 is_syscall(PT_REGS_IP(&current->thread.regs));
Jeff Dike2fc10622006-01-18 17:44:02 -0800144
Jeff Dikeba180fd2007-10-16 01:27:00 -0700145 /*
146 * if there's no signal to deliver, we just put the saved sigmask
147 * back
148 */
Jeff Dike2fc10622006-01-18 17:44:02 -0800149 if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
150 clear_thread_flag(TIF_RESTORE_SIGMASK);
151 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
152 }
Jeff Dike7c7a8942007-03-06 01:42:18 -0800153 return handled_sig;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
156int do_signal(void)
157{
Jeff Dike7c7a8942007-03-06 01:42:18 -0800158 return kern_do_signal(&current->thread.regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159}
160
161/*
162 * Atomically swap in the new signal mask, and wait for a signal.
163 */
164long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
165{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 mask &= _BLOCKABLE;
167 spin_lock_irq(&current->sighand->siglock);
Jeff Dike2fc10622006-01-18 17:44:02 -0800168 current->saved_sigmask = current->blocked;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 siginitset(&current->blocked, mask);
170 recalc_sigpending();
171 spin_unlock_irq(&current->sighand->siglock);
172
Jeff Dike2fc10622006-01-18 17:44:02 -0800173 current->state = TASK_INTERRUPTIBLE;
174 schedule();
175 set_thread_flag(TIF_RESTORE_SIGMASK);
176 return -ERESTARTNOHAND;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177}
178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
180{
Jeff Dike7c7a8942007-03-06 01:42:18 -0800181 return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182}