signal32.c

来自「linux-2.4.29操作系统的源码」· C语言 代码 · 共 1,110 行 · 第 1/2 页

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1991, 1992  Linus Torvalds
 * Copyright (C) 1994 - 2000  Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 */
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>

#include <asm/asm.h>
#include <asm/bitops.h>
#include <asm/pgalloc.h>
#include <asm/stackframe.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include <asm/system.h>
#include <asm/fpu.h>

/*
 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
 */
#define __NR_O32_sigreturn		4119
#define __NR_O32_rt_sigreturn		4193
#define __NR_O32_restart_syscall	4253

#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

extern asmlinkage int do_signal32(sigset_t *oldset, struct pt_regs *regs);

extern asmlinkage void syscall_trace(void);

/* 32-bit compatibility types */

#define _NSIG32_BPW	32
#define _NSIG32_WORDS	(_NSIG / _NSIG32_BPW)

typedef struct {
	unsigned int sig[_NSIG32_WORDS];
} sigset32_t;

typedef unsigned int __sighandler32_t;
typedef void (*vfptr_t)(void);

struct sigaction32 {
	unsigned int		sa_flags;
	__sighandler32_t	sa_handler;
	sigset32_t		sa_mask;
};

/* IRIX compatible stack_t  */
typedef struct sigaltstack32 {
	s32 ss_sp;
	__kernel_size_t32 ss_size;
	int ss_flags;
} stack32_t;

typedef union sigval32 {
	int sival_int;
	s32 sival_ptr;
} sigval_t32;

#define SI_PAD_SIZE32	((SI_MAX_SIZE/sizeof(int)) - 3)

typedef struct siginfo32 {
	int si_signo;
	int si_code;
	int si_errno;

	union {
		int _pad[SI_PAD_SIZE32];

		/* kill() */
		struct {
			__kernel_pid_t32 _pid;	/* sender's pid */
			__kernel_uid_t32 _uid;	/* sender's uid */
		} _kill;

		/* SIGCHLD */
		struct {
			__kernel_pid_t32 _pid;	/* which child */
			__kernel_uid_t32 _uid;	/* sender's uid */
			int _status;		/* exit code */
			__kernel_clock_t32 _utime;
			__kernel_clock_t32 _stime;
		} _sigchld;

		/* IRIX SIGCHLD */
		struct {
			__kernel_pid_t32 _pid;	/* which child */
			__kernel_clock_t32 _utime;
			int _status;		/* exit code */
			__kernel_clock_t32 _stime;
		} _irix_sigchld;

		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
		struct {
			s32 _addr; /* faulting insn/memory ref. */
		} _sigfault;

		/* SIGPOLL, SIGXFSZ (To do ...)  */
		struct {
			int _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
			int _fd;
		} _sigpoll;

		/* POSIX.1b timers */
		struct {
			unsigned int _timer1;
			unsigned int _timer2;
		} _timer;

		/* POSIX.1b signals */
		struct {
			__kernel_pid_t32 _pid;	/* sender's pid */
			__kernel_uid_t32 _uid;	/* sender's uid */
			sigval_t32 _sigval;
		} _rt;

	} _sifields;
} siginfo_t32;

struct ucontext32 {
	u32                 uc_flags;
	s32                 uc_link;
	stack32_t           uc_stack;
	struct sigcontext32 uc_mcontext;
	sigset_t32          uc_sigmask;   /* mask last for extensibility */
};

extern void __put_sigset_unknown_nsig(void);
extern void __get_sigset_unknown_nsig(void);

static inline int put_sigset(const sigset_t *kbuf, sigset32_t *ubuf)
{
	int err = 0;

	if (!access_ok(VERIFY_WRITE, ubuf, sizeof(*ubuf)))
		return -EFAULT;

	switch (_NSIG_WORDS) {
	default:
		__put_sigset_unknown_nsig();
	case 2:
		err |= __put_user (kbuf->sig[1] >> 32, &ubuf->sig[3]);
		err |= __put_user (kbuf->sig[1] & 0xffffffff, &ubuf->sig[2]);
	case 1:
		err |= __put_user (kbuf->sig[0] >> 32, &ubuf->sig[1]);
		err |= __put_user (kbuf->sig[0] & 0xffffffff, &ubuf->sig[0]);
	}

	return err;
}

static inline int get_sigset(sigset_t *kbuf, const sigset32_t *ubuf)
{
	int err = 0;
	unsigned long sig[4];

	if (!access_ok(VERIFY_READ, ubuf, sizeof(*ubuf)))
		return -EFAULT;

	switch (_NSIG_WORDS) {
	default:
		__get_sigset_unknown_nsig();
	case 2:
		err |= __get_user (sig[3], &ubuf->sig[3]);
		err |= __get_user (sig[2], &ubuf->sig[2]);
		kbuf->sig[1] = sig[2] | (sig[3] << 32);
	case 1:
		err |= __get_user (sig[1], &ubuf->sig[1]);
		err |= __get_user (sig[0], &ubuf->sig[0]);
		kbuf->sig[0] = sig[0] | (sig[1] << 32);
	}

	return err;
}

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
save_static_function(sys32_sigsuspend);
static_unused int _sys32_sigsuspend(abi64_no_regargs, struct pt_regs regs)
{
	sigset32_t *uset;
	sigset_t newset, saveset;

	uset = (sigset32_t *) regs.regs[4];
	if (get_sigset(&newset, uset))
		return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);

	spin_lock_irq(&current->sigmask_lock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs.regs[2] = EINTR;
	regs.regs[7] = 1;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal32(&saveset, &regs))
			return -EINTR;
	}
}

save_static_function(sys32_rt_sigsuspend);
static_unused int _sys32_rt_sigsuspend(abi64_no_regargs, struct pt_regs regs)
{
	sigset32_t *uset;
	sigset_t newset, saveset;
        size_t sigsetsize;

	/* XXX Don't preclude handling different sized sigset_t's.  */
	sigsetsize = regs.regs[5];
	if (sigsetsize != sizeof(sigset32_t))
		return -EINVAL;

	uset = (sigset32_t *) regs.regs[4];
	if (get_sigset(&newset, uset))
		return -EFAULT;
	sigdelsetmask(&newset, ~_BLOCKABLE);

	spin_lock_irq(&current->sigmask_lock);
	saveset = current->blocked;
	current->blocked = newset;
        recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs.regs[2] = EINTR;
	regs.regs[7] = 1;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal32(&saveset, &regs))
			return -EINTR;
	}
}

asmlinkage int sys32_sigaction(int sig, const struct sigaction32 *act,
                               struct sigaction32 *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;
	int err = 0;

	if (act) {
		old_sigset_t mask;

		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
			return -EFAULT;
		err |= __get_user((u32)(u64)new_ka.sa.sa_handler,
		                  &act->sa_handler);
		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
		err |= __get_user(mask, &act->sa_mask.sig[0]);
		if (err)
			return -EFAULT;

		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
                        return -EFAULT;
		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		err |= __put_user((u32)(u64)old_ka.sa.sa_handler,
		                  &oact->sa_handler);
		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
                err |= __put_user(0, &oact->sa_mask.sig[1]);
                err |= __put_user(0, &oact->sa_mask.sig[2]);
                err |= __put_user(0, &oact->sa_mask.sig[3]);
                if (err)
			return -EFAULT;
	}

	return ret;
}

asmlinkage int sys32_sigaltstack(abi64_no_regargs, struct pt_regs regs)
{
	const stack32_t *uss = (const stack32_t *) regs.regs[4];
	stack32_t *uoss = (stack32_t *) regs.regs[5];
	unsigned long usp = regs.regs[29];
	stack_t kss, koss;
	int ret, err = 0;
	mm_segment_t old_fs = get_fs();
	s32 sp;

	if (uss) {
		if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
			return -EFAULT;
		err |= __get_user(sp, &uss->ss_sp);
		kss.ss_sp = (void *) (long) sp;
		err |= __get_user(kss.ss_size, &uss->ss_size);
		err |= __get_user(kss.ss_flags, &uss->ss_flags);
		if (err)
			return -EFAULT;
	}

	set_fs (KERNEL_DS);
	ret = do_sigaltstack(uss ? &kss : NULL , uoss ? &koss : NULL, usp);
	set_fs (old_fs);

	if (!ret && uoss) {
		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
			return -EFAULT;
		sp = (int) (long) koss.ss_sp;
		err |= __put_user(sp, &uoss->ss_sp);
		err |= __put_user(koss.ss_size, &uoss->ss_size);
		err |= __put_user(koss.ss_flags, &uoss->ss_flags);
		if (err)
			return -EFAULT;
	}
	return ret;
}

static asmlinkage int restore_sigcontext32(struct pt_regs *regs,
					   struct sigcontext32 *sc)
{
	int err = 0;

	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
	err |= __get_user(regs->hi, &sc->sc_mdhi);
	err |= __get_user(regs->lo, &sc->sc_mdlo);

#define restore_gp_reg(i) do {						\
	err |= __get_user(regs->regs[i], &sc->sc_regs[i]);		\
} while(0)
	restore_gp_reg( 1); restore_gp_reg( 2); restore_gp_reg( 3);
	restore_gp_reg( 4); restore_gp_reg( 5); restore_gp_reg( 6);
	restore_gp_reg( 7); restore_gp_reg( 8); restore_gp_reg( 9);
	restore_gp_reg(10); restore_gp_reg(11); restore_gp_reg(12);
	restore_gp_reg(13); restore_gp_reg(14); restore_gp_reg(15);
	restore_gp_reg(16); restore_gp_reg(17); restore_gp_reg(18);
	restore_gp_reg(19); restore_gp_reg(20); restore_gp_reg(21);
	restore_gp_reg(22); restore_gp_reg(23); restore_gp_reg(24);
	restore_gp_reg(25); restore_gp_reg(26); restore_gp_reg(27);
	restore_gp_reg(28); restore_gp_reg(29); restore_gp_reg(30);
	restore_gp_reg(31);
#undef restore_gp_reg

	err |= __get_user(current->used_math, &sc->sc_used_math);

	if (current->used_math) {
		/* restore fpu context if we have used it before */
		own_fpu();
		err |= restore_fp_context32(sc);
	} else {
		/* signal handler may have used FPU.  Give it up. */
		lose_fpu();
	}

	return err;
}

struct sigframe {
	u32 sf_ass[4];			/* argument save space for o32 */
	u32 sf_code[2];			/* signal trampoline */
	struct sigcontext32 sf_sc;
	sigset_t sf_mask;
};

struct rt_sigframe32 {
	u32 rs_ass[4];			/* argument save space for o32 */
	u32 rs_code[2];			/* signal trampoline */
	struct siginfo32 rs_info;
	struct ucontext32 rs_uc;
};

static int copy_siginfo_to_user32(siginfo_t32 *to, siginfo_t *from)
{
	int err;

	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t32)))
		return -EFAULT;

	/* If you change siginfo_t structure, please be sure
	   this code is fixed accordingly.
	   It should never copy any pad contained in the structure
	   to avoid security leaks, but must copy the generic
	   3 ints plus the relevant union member.
	   This routine must convert siginfo from 64bit to 32bit as well
	   at the same time.  */
	err = __put_user(from->si_signo, &to->si_signo);
	err |= __put_user(from->si_errno, &to->si_errno);
	err |= __put_user((short)from->si_code, &to->si_code);
	if (from->si_code < 0)
		err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
	else {
		switch (from->si_code >> 16) {
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		case __SI_FAULT >> 16:
			err |= __put_user((long)from->si_addr, &to->si_addr);
			break;
		case __SI_POLL >> 16:
			err |= __put_user(from->si_band, &to->si_band);
			err |= __put_user(from->si_fd, &to->si_fd);
			break;
		/* case __SI_RT: This is not generated by the kernel as of now.  */
		}
	}
	return err;
}

asmlinkage void sys32_sigreturn(abi64_no_regargs, struct pt_regs regs)
{
	struct sigframe *frame;
	sigset_t blocked;

	frame = (struct sigframe *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
		goto badframe;

	sigdelsetmask(&blocked, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = blocked;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	if (restore_sigcontext32(&regs, &frame->sf_sc))
		goto badframe;

	/*
	 * Don't let your children do this ...
	 */
	if (current->ptrace & PT_TRACESYS)
		syscall_trace();
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tret_from_sys_call"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

asmlinkage void sys32_rt_sigreturn(abi64_no_regargs, struct pt_regs regs)
{
	struct rt_sigframe32 *frame;
	sigset_t set;
	stack_t st;
	s32 sp;

	frame = (struct rt_sigframe32 *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	if (restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext))
		goto badframe;

	/* The ucontext contains a stack32_t, so we must convert!  */
	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
		goto badframe;
	st.ss_size = (long) sp;
	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
		goto badframe;
	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
		goto badframe;

	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, regs.regs[29]);

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tret_from_sys_call"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

static int inline setup_sigcontext32(struct pt_regs *regs,
				     struct sigcontext32 *sc)
{
	int err = 0;

	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
	err |= __put_user(regs->cp0_status, &sc->sc_status);

#define save_gp_reg(i) {						\
	err |= __put_user(regs->regs[i], &sc->sc_regs[i]);		\
} while(0)
	__put_user(0, &sc->sc_regs[0]); save_gp_reg(1); save_gp_reg(2);
	save_gp_reg(3); save_gp_reg(4); save_gp_reg(5); save_gp_reg(6);
	save_gp_reg(7); save_gp_reg(8); save_gp_reg(9); save_gp_reg(10);
	save_gp_reg(11); save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
	save_gp_reg(15); save_gp_reg(16); save_gp_reg(17); save_gp_reg(18);
	save_gp_reg(19); save_gp_reg(20); save_gp_reg(21); save_gp_reg(22);
	save_gp_reg(23); save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
	save_gp_reg(27); save_gp_reg(28); save_gp_reg(29); save_gp_reg(30);
	save_gp_reg(31);
#undef save_gp_reg

	err |= __put_user(regs->hi, &sc->sc_mdhi);
	err |= __put_user(regs->lo, &sc->sc_mdlo);
	err |= __put_user(regs->cp0_cause, &sc->sc_cause);
	err |= __put_user(regs->cp0_badvaddr, &sc->sc_badvaddr);

	err |= __put_user(current->used_math, &sc->sc_used_math);

	if (!current->used_math)
		goto out;

	/* 
	 * Save FPU state to signal context.  Signal handler will "inherit"
	 * current FPU state.
	 */
	if (!is_fpu_owner()) {
		own_fpu();
		restore_fp(current);
	}
	err |= save_fp_context32(sc);

out: