signal32.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*
 * 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>

#define DEBUG_SIG 0

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

extern asmlinkage int do_signal32(sigset_t *oldset, struct pt_regs *regs);
extern asmlinkage int (*save_fp_context)(struct sigcontext *sc);
extern asmlinkage int (*restore_fp_context)(struct sigcontext *sc);

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;
	unsigned int		sa_restorer;
	int			sa_resv[1];     /* reserved */
};

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

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.
 */
asmlinkage inline int sys32_sigsuspend(abi64_no_regargs, struct pt_regs regs)
{
	sigset32_t *uset;
	sigset_t newset, saveset;

	save_static(&regs);
	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_rt_sigsuspend(abi64_no_regargs, struct pt_regs regs)
{
	sigset32_t *uset;
	sigset_t newset, saveset;
        size_t sigsetsize;

	save_static(&regs);
	/* 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]);
		err |= __get_user((u32)(u64)new_ka.sa.sa_restorer,
		                   &act->sa_restorer);
		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]);
		err |= __put_user((u32)(u64)old_ka.sa.sa_restorer,
		                  &oact->sa_restorer);
                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_size = (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 inline int restore_thread_fp_context(struct sigcontext *sc)
{
	u64 *pfreg = &current->thread.fpu.soft.regs[0];
	int err = 0;

	/*
	 * Copy all 32 64-bit values.
	 */

#define restore_fpr(i) 						\
	do { err |= __get_user(pfreg[i], &sc->sc_fpregs[i]); } while(0)

	restore_fpr( 0); restore_fpr( 1); restore_fpr( 2); restore_fpr( 3);
	restore_fpr( 4); restore_fpr( 5); restore_fpr( 6); restore_fpr( 7);
	restore_fpr( 8); restore_fpr( 9); restore_fpr(10); restore_fpr(11);
	restore_fpr(12); restore_fpr(13); restore_fpr(14); restore_fpr(15);
	restore_fpr(16); restore_fpr(17); restore_fpr(18); restore_fpr(19);
	restore_fpr(20); restore_fpr(21); restore_fpr(22); restore_fpr(23);
	restore_fpr(24); restore_fpr(25); restore_fpr(26); restore_fpr(27);
	restore_fpr(28); restore_fpr(29); restore_fpr(30); restore_fpr(31);

	err |= __get_user(current->thread.fpu.soft.sr, &sc->sc_fpc_csr);

	return err;
}

static inline int save_thread_fp_context(struct sigcontext *sc)
{
	u64 *pfreg = &current->thread.fpu.soft.regs[0];
	int err = 0;

#define save_fpr(i) 							\
	do { err |= __put_user(pfreg[i], &sc->sc_fpregs[i]); } while(0)

	save_fpr( 0); save_fpr( 1); save_fpr( 2); save_fpr( 3);
	save_fpr( 4); save_fpr( 5); save_fpr( 6); save_fpr( 7);
	save_fpr( 8); save_fpr( 9); save_fpr(10); save_fpr(11);
	save_fpr(12); save_fpr(13); save_fpr(14); save_fpr(15);
	save_fpr(16); save_fpr(17); save_fpr(18); save_fpr(19);
	save_fpr(20); save_fpr(21); save_fpr(22); save_fpr(23);
	save_fpr(24); save_fpr(25); save_fpr(26); save_fpr(27);
	save_fpr(28); save_fpr(29); save_fpr(30); save_fpr(31);

	err |= __put_user(current->thread.fpu.soft.sr, &sc->sc_fpc_csr);

	return err;
}

static asmlinkage int restore_sigcontext(struct pt_regs *regs,
					 struct sigcontext *sc)
{
	int owned_fp;
	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(owned_fp, &sc->sc_ownedfp);
	err |= __get_user(current->used_math, &sc->sc_used_math);

	if (owned_fp) {
		err |= restore_fp_context(sc);
		goto out;
	}

	if (IS_FPU_OWNER()) {
		/* Signal handler acquired FPU - give it back */
		CLEAR_FPU_OWNER();
		regs->cp0_status &= ~ST0_CU1;
	}
	if (current->used_math) {
		/* Undo possible contamination of thread state */
		err |= restore_thread_fp_context(sc);
	}

out:
	return err;
}

struct sigframe {
	u32 sf_ass[4];			/* argument save space for o32 */
	u32 sf_code[2];			/* signal trampoline */
	struct sigcontext 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 ucontext 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_sigcontext(&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;

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

	if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
		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_sigcontext(struct pt_regs *regs,
				   struct sigcontext *sc)
{
	int owned_fp;
	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);