syscall.c

linux进程跟踪的工具和源代码

#elif defined (M68K)
	static int d0;
#elif defined (ARM)
	static int r0;
#elif defined (ALPHA)
	static long r0;
	static long a3;
#elif defined (SPARC)
	static struct regs regs;
	static unsigned long trap;
#elif defined(MIPS)
	static long a3;
	static long r2;
#elif defined(S390)
	static long gpr2;
	static long pc;
#elif defined(HPPA)
	static long r28;
#endif 
#endif /* LINUX */
#ifdef FREEBSD
	struct reg regs;
#endif /* FREEBSD */	

int
get_scno(tcp)
struct tcb *tcp;
{
	long scno = 0;
#ifndef USE_PROCFS
	int pid = tcp->pid;
#endif /* !PROCFS */	

#ifdef LINUX
#if defined(S390)
	if (upeek(tcp->pid,PT_PSWADDR,&pc) < 0)
		return -1;
	scno = ptrace(PTRACE_PEEKTEXT, tcp->pid, (char *)(pc-4),0);
	if (errno)
		return -1;
	scno&=0xFF;
#elif defined (POWERPC)
	if (upeek(pid, 4*PT_R0, &scno) < 0)
		return -1;
	if (!(tcp->flags & TCB_INSYSCALL)) {
		/* Check if we return from execve. */
		if (scno == 0 && (tcp->flags & TCB_WAITEXECVE)) {
			tcp->flags &= ~TCB_WAITEXECVE;
			return 0;
		}
	}
#elif defined (I386)
	if (upeek(pid, 4*ORIG_EAX, &scno) < 0)
		return -1;
#elif defined(IA64)
#define IA64_PSR_IS	((long)1 << 34)
	if (upeek (pid, PT_CR_IPSR, &psr) >= 0)
		ia32 = (psr & IA64_PSR_IS);
	if (!(tcp->flags & TCB_INSYSCALL)) {
		if (ia32) {
			if (upeek(pid, PT_R8, &scno) < 0)
				return -1;
		} else {
			if (upeek (pid, PT_R15, &scno) < 0)
				return -1;
		}
	} else {
		/* syscall in progress */
		if (upeek (pid, PT_R8, &r8) < 0)
			return -1;
		if (upeek (pid, PT_R10, &r10) < 0)
			return -1;
	}
#elif defined (ARM)
	{ 
	    long pc;
	    upeek(pid, 4*15, &pc);
	    umoven(tcp, pc-4, 4, (char *)&scno);
	    scno &= 0x000fffff;
	}
#elif defined (M68K)
	if (upeek(pid, 4*PT_ORIG_D0, &scno) < 0)
		return -1;
#elif defined (MIPS)
	if (upeek(pid, REG_A3, &a3) < 0)
	  	return -1;

	if(!(tcp->flags & TCB_INSYSCALL)) {
	  	if (upeek(pid, REG_V0, &scno) < 0)
		  	return -1;

		if (scno < 0 || scno > nsyscalls) {
			if(a3 == 0 || a3 == -1) {
				if(debug)
					fprintf (stderr, "stray syscall exit: v0 = %ld\n", scno);
				return 0;
			}
		}
	} else {
	  	if (upeek(pid, REG_V0, &r2) < 0)
	    		return -1;
	}
#elif defined (ALPHA)
	if (upeek(pid, REG_A3, &a3) < 0)
		return -1;

	if (!(tcp->flags & TCB_INSYSCALL)) {
		if (upeek(pid, REG_R0, &scno) < 0)
			return -1;

		/* Check if we return from execve. */
		if (scno == 0 && tcp->flags & TCB_WAITEXECVE) {
			tcp->flags &= ~TCB_WAITEXECVE;
			return 0;
		}

		/*
		 * Do some sanity checks to figure out if it's
		 * really a syscall entry
		 */
		if (scno < 0 || scno > nsyscalls) {
			if (a3 == 0 || a3 == -1) {
				if (debug)
					fprintf (stderr, "stray syscall exit: r0 = %ld\n", scno);
				return 0;
			}
		}
	}
	else {
		if (upeek(pid, REG_R0, &r0) < 0)
			return -1;
	}
#elif defined (SPARC)
	/* Everything we need is in the current register set. */
	if (ptrace(PTRACE_GETREGS,pid,(char *)&regs,0) < 0)
		return -1;

        /* If we are entering, then disassemble the syscall trap. */
	if (!(tcp->flags & TCB_INSYSCALL)) {
		/* Retrieve the syscall trap instruction. */
		errno = 0;
		trap = ptrace(PTRACE_PEEKTEXT,pid,(char *)regs.r_pc,0);
		if (errno)
			return -1;

		/* Disassemble the trap to see what personality to use. */
		switch (trap) {
		case 0x91d02010:
			/* Linux/SPARC syscall trap. */
			set_personality(0);
			break;
		case 0x91d0206d:
			/* Linux/SPARC64 syscall trap. */
			fprintf(stderr,"syscall: Linux/SPARC64 not supported yet\n");
			return -1;
		case 0x91d02000:
			/* SunOS syscall trap. (pers 1) */
			fprintf(stderr,"syscall: SunOS no support\n");
			return -1;
		case 0x91d02008:
			/* Solaris 2.x syscall trap. (per 2) */
			set_personality(1);
			break; 
		case 0x91d02009:
			/* NetBSD/FreeBSD syscall trap. */
			fprintf(stderr,"syscall: NetBSD/FreeBSD not supported\n");
			return -1;
		case 0x91d02027:
			/* Solaris 2.x gettimeofday */
			set_personality(1);
			break;
		default:
			/* Unknown syscall trap. */
			if(tcp->flags & TCB_WAITEXECVE) {
				tcp->flags &= ~TCB_WAITEXECVE;
				return 0;
			}
			fprintf(stderr,"syscall: unknown syscall trap %08x %08x\n", trap, regs.r_pc);
			return -1;
		}

		/* Extract the system call number from the registers. */
		if (trap == 0x91d02027)
			scno = 156;
		else
			scno = regs.r_g1;
		if (scno == 0) {
			scno = regs.r_o0;
			memmove (&regs.r_o0, &regs.r_o1, 7*sizeof(regs.r_o0));
		}
	}
#elif defined(HPPA)
	if (upeek(pid, PT_GR20, &scno) < 0)
		return -1;
	if (!(tcp->flags & TCB_INSYSCALL)) {
		/* Check if we return from execve. */
		if ((tcp->flags & TCB_WAITEXECVE)) {
			tcp->flags &= ~TCB_WAITEXECVE;
			return 0;
		}
	}
#endif 
#endif /* LINUX */
#ifdef SUNOS4
	if (upeek(pid, uoff(u_arg[7]), &scno) < 0)
		return -1;
#endif
#ifdef USE_PROCFS
#ifdef HAVE_PR_SYSCALL
	scno = tcp->status.PR_SYSCALL;
#else /* !HAVE_PR_SYSCALL */
#ifndef FREEBSD
	scno = tcp->status.PR_WHAT;
#else /* FREEBSD */
	if (pread(tcp->pfd_reg, &regs, sizeof(regs), 0) < 0) {
	        perror("pread");
                return -1;
        }
	switch (regs.r_eax) {
	case SYS_syscall:
	case SYS___syscall:
    	        pread(tcp->pfd, &scno, sizeof(scno), regs.r_esp + sizeof(int));
	        break;
	default:
	        scno = regs.r_eax;
	        break;
	}
#endif /* FREEBSD */
#endif /* !HAVE_PR_SYSCALL */
#endif /* USE_PROCFS */
	if (!(tcp->flags & TCB_INSYSCALL))
		tcp->scno = scno;
	return 1;
}


int
syscall_fixup(tcp)
struct tcb *tcp;
{
#ifndef USE_PROCFS
	int pid = tcp->pid;
#else /* USE_PROCFS */	
	int scno = tcp->scno;

	if (!(tcp->flags & TCB_INSYSCALL)) {
		if (tcp->status.PR_WHY != PR_SYSENTRY) {
			if (
			    scno == SYS_fork
#ifdef SYS_vfork
			    || scno == SYS_vfork
#endif /* SYS_vfork */
			    ) {
				/* We are returning in the child, fake it. */
				tcp->status.PR_WHY = PR_SYSENTRY;
				trace_syscall(tcp);
				tcp->status.PR_WHY = PR_SYSEXIT;
			}
			else {
				fprintf(stderr, "syscall: missing entry\n");
				tcp->flags |= TCB_INSYSCALL;
			}
		}
	}
	else {
		if (tcp->status.PR_WHY != PR_SYSEXIT) {
			fprintf(stderr, "syscall: missing exit\n");
			tcp->flags &= ~TCB_INSYSCALL;
		}
	}
#endif /* USE_PROCFS */
#ifdef SUNOS4
	if (!(tcp->flags & TCB_INSYSCALL)) {
		if (scno == 0) {
			fprintf(stderr, "syscall: missing entry\n");
			tcp->flags |= TCB_INSYSCALL;
		}
	}
	else {
		if (scno != 0) {
			if (debug) {
				/*
				 * This happens when a signal handler
				 * for a signal which interrupted a
				 * a system call makes another system call.
				 */
				fprintf(stderr, "syscall: missing exit\n");
			}
			tcp->flags &= ~TCB_INSYSCALL;
		}
	}
#endif /* SUNOS4 */
#ifdef LINUX
#if defined (I386)
	if (upeek(pid, 4*EAX, &eax) < 0)
		return -1;
	if (eax != -ENOSYS && !(tcp->flags & TCB_INSYSCALL)) {
		if (debug)
			fprintf(stderr, "stray syscall exit: eax = %ld\n", eax);
		return 0;
	}
#elif defined (S390)
	if (upeek(pid, PT_GPR2, &gpr2) < 0)
		return -1;
	if (gpr2 != -ENOSYS && !(tcp->flags & TCB_INSYSCALL)) {
		if (debug)
			fprintf(stderr, "stray syscall exit: gpr2 = %ld\n", gpr2);
		return 0;
	}
#elif defined (POWERPC)
# define SO_MASK 0x10000000
	if (upeek(pid, 4*PT_CCR, &flags) < 0)
		return -1;
	if (upeek(pid, 4*PT_R3, &result) < 0)
		return -1;
	if (flags & SO_MASK)
		result = -result;
#elif defined (M68K)
	if (upeek(pid, 4*PT_D0, &d0) < 0)
		return -1;
	if (d0 != -ENOSYS && !(tcp->flags & TCB_INSYSCALL)) {
		if (debug)
			fprintf(stderr, "stray syscall exit: d0 = %ld\n", d0);
		return 0;
	}
#elif defined (ARM)
	if (upeek(pid, 4*0, (long *)&r0) < 0)
		return -1;
	if ( 0 && r0 != -ENOSYS && !(tcp->flags & TCB_INSYSCALL)) {
		if (debug)
			fprintf(stderr, "stray syscall exit: d0 = %ld\n", r0);
		return 0;
	}
#elif defined (HPPA)
	if (upeek(pid, PT_GR28, &r28) < 0)
		return -1;
#endif
#endif /* LINUX */
	return 1;
}

int
get_error(tcp)
struct tcb *tcp;
{
	int u_error = 0;
#ifdef LINUX
#ifdef S390
		if (gpr2 && (unsigned) -gpr2 < nerrnos) {
			tcp->u_rval = -1;
			u_error = -gpr2;
		}
		else {
			tcp->u_rval = gpr2;
			u_error = 0;
		}
#else /* !S390 */
#ifdef I386
		if (eax < 0 && -eax < nerrnos) {
			tcp->u_rval = -1;
			u_error = -eax;
		}
		else {
			tcp->u_rval = eax;
			u_error = 0;
		}
#else /* !I386 */
#ifdef IA64
		if (ia32) {
			int err;

			err = (int)r8;
			if (err < 0 && -err < nerrnos) {
				tcp->u_rval = -1;
				u_error = -err;
			}
			else {
				tcp->u_rval = err;
				u_error = 0;
			}
		} else {
			if (r10) {
				tcp->u_rval = -1;
				u_error = r8;
			} else {
				tcp->u_rval = r8;
				u_error = 0;
			}
		}
#else /* !IA64 */
#ifdef MIPS
		if (a3) {
		  	tcp->u_rval = -1;
			u_error = r2;
		} else {
		  	tcp->u_rval = r2;
			u_error = 0;
		}
#else
#ifdef POWERPC
		if (result && (unsigned) -result < nerrnos) {
			tcp->u_rval = -1;
			u_error = -result;
		}
		else {
			tcp->u_rval = result;
			u_error = 0;
		}
#else /* !POWERPC */
#ifdef M68K
		if (d0 && (unsigned) -d0 < nerrnos) {
			tcp->u_rval = -1;
			u_error = -d0;
		}
		else {
			tcp->u_rval = d0;
			u_error = 0;
		}
#else /* !M68K */
#ifdef ARM
		if (r0 && (unsigned) -r0 < nerrnos) {
			tcp->u_rval = -1;
			u_error = -r0;
		}
		else {
			tcp->u_rval = r0;
			u_error = 0;
		}
#else /* !ARM */
#ifdef ALPHA
		if (a3) {
			tcp->u_rval = -1;
			u_error = r0;
		}
		else {
			tcp->u_rval = r0;
			u_error = 0;
		}
#else /* !ALPHA */
#ifdef SPARC
		if (regs.r_psr & PSR_C) {
			tcp->u_rval = -1;
			u_error = regs.r_o0;
		}
		else {
			tcp->u_rval = regs.r_o0;
			u_error = 0;
		}
#else /* !SPARC */
#ifdef HPPA
		if (r28 && (unsigned) -r28 < nerrnos) {
			tcp->u_rval = -1;
			u_error = -r28;
		}
		else {
			tcp->u_rval = r28;
			u_error = 0;
		}
#endif /* HPPA */
#endif /* SPARC */
#endif /* ALPHA */
#endif /* ARM */
#endif /* M68K */
#endif /* POWERPC */
#endif /* MIPS */
#endif /* IA64 */
#endif /* I386 */
#endif /* S390 */
#endif /* LINUX */
#ifdef SUNOS4
		/* get error code from user struct */
		if (upeek(pid, uoff(u_error), &u_error) < 0)
			return -1;
		u_error >>= 24; /* u_error is a char */

		/* get system call return value */
		if (upeek(pid, uoff(u_rval1), &tcp->u_rval) < 0)
			return -1;
#endif /* SUNOS4 */
#ifdef SVR4
#ifdef SPARC
		/* Judicious guessing goes a long way. */
		if (tcp->status.pr_reg[R_PSR] & 0x100000) {
			tcp->u_rval = -1;
			u_error = tcp->status.pr_reg[R_O0];
		}
		else {
			tcp->u_rval = tcp->status.pr_reg[R_O0];
			u_error = 0;
		}
#endif /* SPARC */
#ifdef I386
		/* Wanna know how to kill an hour single-stepping? */
		if (tcp->status.PR_REG[EFL] & 0x1) {
			tcp->u_rval = -1;
			u_error = tcp->status.PR_REG[EAX];
		}
		else {
			tcp->u_rval = tcp->status.PR_REG[EAX];
#ifdef HAVE_LONG_LONG
			tcp->u_lrval =
				((unsigned long long) tcp->status.PR_REG[EDX] << 32) +
				tcp->status.PR_REG[EAX];
#endif
			u_error = 0;
		}
#endif /* I386 */
#ifdef MIPS
		if (tcp->status.pr_reg[CTX_A3]) {
			tcp->u_rval = -1;
			u_error = tcp->status.pr_reg[CTX_V0];
		}
		else {
			tcp->u_rval = tcp->status.pr_reg[CTX_V0];
			u_error = 0;
		}
#endif /* MIPS */
#endif /* SVR4 */
#ifdef FREEBSD
		if (regs.r_eflags & PSL_C) {
 		        tcp->u_rval = -1;
		        u_error = regs.r_eax;
		} else {
		        tcp->u_rval = regs.r_eax;
			tcp->u_lrval =
			  ((unsigned long long) regs.r_edx << 32) +  regs.r_eax;
		        u_error = 0;
		}
#endif /* FREEBSD */	
	tcp->u_error = u_error;
	return 1;
}

int syscall_enter(tcp)
struct tcb *tcp;
{
#ifndef USE_PROCFS
	int pid = tcp->pid;
#endif /* !USE_PROCFS */	
#ifdef LINUX
#if defined(S390)
	{
		int i;
		if (tcp->scno >= 0 && tcp->scno < nsyscalls && sysent[tcp->scno].nargs != -1)
			tcp->u_nargs = sysent[tcp->scno].nargs;
		else 
     	        	tcp->u_nargs = MAX_ARGS;
		for (i = 0; i < tcp->u_nargs; i++) {
			if (upeek(pid,i==0 ? PT_ORIGGPR2:PT_GPR2+(i<<2), &tcp->u_arg[i]) < 0)
				return -1;
		}
	}
#elif defined (ALPHA)
	{
		int i;
		if (tcp->scno >= 0 && tcp->scno < nsyscalls && sysent[tcp->scno].nargs != -1)
			tcp->u_nargs = sysent[tcp->scno].nargs;
		else 
     	        	tcp->u_nargs = MAX_ARGS;
		for (i = 0; i < tcp->u_nargs; i++) {
			/* WTA: if scno is out-of-bounds this will bomb. Add range-check
			 * for scno somewhere above here!
			 */
			if (upeek(pid, REG_A0+i, &tcp->u_arg[i]) < 0)
				return -1;
		}
	}
#elif defined (IA64)
	{
		unsigned long *bsp, cfm, i;

		if (upeek(pid, PT_AR_BSP, (long *) &bsp) < 0)
			return -1;
		if (upeek(pid, PT_CFM, (long *) &cfm) < 0)
			return -1;

		bsp = ia64_rse_skip_regs(bsp, -(cfm & 0x7f));

		if (tcp->scno >= 0 && tcp->scno < nsyscalls && sysent[tcp->scno].nargs != -1)
			tcp->u_nargs = sysent[tcp->scno].nargs;
		else 
     	        	tcp->u_nargs = MAX_ARGS;
		for (i = 0; i < tcp->u_nargs; ++i) {
			if (umoven(tcp, (unsigned long) ia64_rse_skip_regs(bsp, i), sizeof(long),
				   (char *) &tcp->u_arg[i])
			    < 0)
				return -1;
		}
	}
#elif defined (MIPS)
	{
	  	long sp;
	  	int i, nargs;

		if (tcp->scno >= 0 && tcp->scno < nsyscalls && sysent[tcp->scno].nargs != -1)
			nargs = tcp->u_nargs = sysent[tcp->scno].nargs;
		else 
     	        	nargs = tcp->u_nargs = MAX_ARGS;
		if(nargs > 4) {
		  	if(upeek(pid, REG_SP, &sp) < 0)
			  	return -1;
			for(i = 0; i < 4; i++) {
			  	if (upeek(pid, REG_A0 + i, &tcp->u_arg[i])<0)
				  	return -1;
			}
			umoven(tcp, sp+16, (nargs-4) * sizeof(tcp->u_arg[0]),
			       (char *)(tcp->u_arg + 4));
		} else {
		  	for(i = 0; i < nargs; i++) {
			  	if (upeek(pid, REG_A0 + i, &tcp->u_arg[i]) < 0)
				  	return -1;
			}
		}
	}
#elif defined (POWERPC)
	{
		int i;
		if (tcp->scno >= 0 && tcp->scno < nsyscalls && sysent[tcp->scno].nargs != -1)
			tcp->u_nargs = sysent[tcp->scno].nargs;
		else 
     	        	tcp->u_nargs = MAX_ARGS;
		for (i = 0; i < tcp->u_nargs; i++) {
			if (upeek(pid, (i==0) ? (4*PT_ORIG_R3) : ((i+PT_R3)*4), &tcp->u_arg[i]) < 0)
				return -1;
		}
	}
#elif defined (SPARC)
	{
		int i;