patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/ptrace.c

• Lines: 450
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/kernel/ptrace.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/kernel/ptrace.c linux-2.4.20/arch/x86_64/kernel/ptrace.c
@@ -0,0 +1,449 @@
+/* ptrace.c */
+/* By Ross Biro 1/23/92 */
+/*
+ * Pentium III FXSR, SSE support
+ *	Gareth Hughes <gareth@valinux.com>, May 2000
+ * 
+ * x86-64 port 2000-2002 Andi Kleen
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+#include <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/debugreg.h>
+
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/* determines which flags the user has access to. */
+/* 1 = access 0 = no access */
+#define FLAG_MASK 0x44dd5UL
+
+/* set's the trap flag. */
+#define TRAP_FLAG 0x100UL
+
+/*
+ * eflags and offset of eflags on child stack..
+ */
+#define EFLAGS offsetof(struct pt_regs, eflags)
+#define EFL_OFFSET ((int)(EFLAGS-sizeof(struct pt_regs)))
+
+/*
+ * this routine will get a word off of the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */   
+static inline unsigned long get_stack_long(struct task_struct *task, int offset)
+{
+	unsigned char *stack;
+
+	stack = (unsigned char *)task->thread.rsp0;
+	stack += offset;
+	return (*((unsigned long *)stack));
+}
+
+/*
+ * this routine will put a word on the processes privileged stack. 
+ * the offset is how far from the base addr as stored in the TSS.  
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline long put_stack_long(struct task_struct *task, int offset,
+	unsigned long data)
+{
+	unsigned char * stack;
+
+	stack = (unsigned char *) task->thread.rsp0;
+	stack += offset;
+	*(unsigned long *) stack = data;
+	return 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure the single step bit is not set.
+ */
+void ptrace_disable(struct task_struct *child)
+{ 
+	long tmp;
+
+	tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
+	put_stack_long(child, EFL_OFFSET, tmp);
+}
+
+static int putreg(struct task_struct *child,
+	unsigned long regno, unsigned long value)
+{
+	unsigned long tmp; 
+	switch (regno) {
+		case offsetof(struct user_regs_struct,fs):
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.fsindex = value & 0xffff; 
+			return 0; 
+		case offsetof(struct user_regs_struct,gs):
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.gsindex = value & 0xffff;
+			return 0;
+		case offsetof(struct user_regs_struct,ds):
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.ds = value & 0xffff;
+			return 0;
+		case offsetof(struct user_regs_struct,es): 
+			if (value && (value & 3) != 3)
+				return -EIO;
+			child->thread.es = value & 0xffff;
+			return 0;
+		case offsetof(struct user_regs_struct,fs_base):
+			if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
+				return -EIO; 
+			child->thread.fs = value;
+			return 0;
+		case offsetof(struct user_regs_struct,gs_base):
+			if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
+				return -EIO; 
+			child->thread.gs = value;
+			return 0;
+		case offsetof(struct user_regs_struct, eflags):
+			value &= FLAG_MASK;
+			tmp = get_stack_long(child, EFL_OFFSET); 
+			tmp &= ~FLAG_MASK; 
+			value |= tmp;
+			break;
+		case offsetof(struct user_regs_struct,cs): 
+			if ((value & 3) != 3)
+				return -EIO;
+			value &= 0xffff;
+			break;
+		case offsetof(struct user_regs_struct,ss):
+			if ((value & 3) != 3)
+				return -EIO;
+			value &= 0xffff;
+            break;
+	}      
+	put_stack_long(child, regno - sizeof(struct pt_regs), value);
+	return 0;
+}
+
+static unsigned long getreg(struct task_struct *child, unsigned long regno)
+{
+	switch (regno) {
+		case offsetof(struct user_regs_struct, fs):
+			return child->thread.fsindex;
+		case offsetof(struct user_regs_struct, gs):
+			return child->thread.gsindex;
+		case offsetof(struct user_regs_struct, ds):
+			return child->thread.ds;
+		case offsetof(struct user_regs_struct, es):
+			return child->thread.es; 
+		case offsetof(struct user_regs_struct, fs_base):
+			return child->thread.fs;
+		case offsetof(struct user_regs_struct, gs_base):
+			return child->thread.gs;
+		default:
+			regno = regno - sizeof(struct pt_regs);
+			return get_stack_long(child, regno);
+	}
+
+}
+
+asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+{
+	struct task_struct *child;
+	struct user * dummy = NULL;
+	long i, ret;
+
+	/* This lock_kernel fixes a subtle race with suid exec */
+	lock_kernel();
+	ret = -EPERM;
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->ptrace & PT_PTRACED)
+			goto out;
+		/* set the ptrace bit in the process flags. */
+		current->ptrace |= PT_PTRACED;
+		ret = 0;
+		goto out;
+	}
+	ret = -ESRCH;
+	read_lock(&tasklist_lock);
+	child = find_task_by_pid(pid);
+	if (child)
+		get_task_struct(child);
+	read_unlock(&tasklist_lock);
+	if (!child)
+		goto out;
+
+	ret = -EPERM;
+	if (pid == 1)		/* you may not mess with init */
+		goto out_tsk;
+
+	if (request == PTRACE_ATTACH) {
+		ret = ptrace_attach(child);
+		goto out_tsk;
+	}
+	ret = -ESRCH;
+	if (!(child->ptrace & PT_PTRACED))
+		goto out_tsk;
+	if (child->state != TASK_STOPPED) {
+		if (request != PTRACE_KILL)
+			goto out_tsk;
+	}
+	if (child->p_pptr != current)
+		goto out_tsk;
+	switch (request) {
+	/* when I and D space are separate, these will need to be fixed. */
+	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+	case PTRACE_PEEKDATA: {
+		unsigned long tmp;
+		int copied;
+
+		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+		ret = -EIO;
+		if (copied != sizeof(tmp))
+			break;
+		ret = put_user(tmp,(unsigned long *) data);
+		break;
+	}
+
+	/* read the word at location addr in the USER area. */
+	case PTRACE_PEEKUSR: {
+		unsigned long tmp;
+
+		ret = -EIO;
+		if ((addr & 3) || addr < 0 || 
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		tmp = 0;  /* Default return condition */
+		if(addr < sizeof(struct user_regs_struct))
+			tmp = getreg(child, addr);
+		if(addr >= (long) &dummy->u_debugreg[0] &&
+		   addr <= (long) &dummy->u_debugreg[7]){
+			addr -= (long) &dummy->u_debugreg[0];
+			addr = addr >> 2;
+			tmp = child->thread.debugreg[addr];
+		}
+		ret = put_user(tmp,(unsigned long *) data);
+		break;
+	}
+
+	/* when I and D space are separate, this will have to be fixed. */
+	case PTRACE_POKETEXT: /* write the word at location addr. */
+	case PTRACE_POKEDATA:
+		ret = 0;
+		if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
+			break;
+		ret = -EIO;
+		break;
+
+	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
+		ret = -EIO;
+		if ((addr & 3) || addr < 0 || 
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		if (addr < sizeof(struct user_regs_struct)) {
+			ret = putreg(child, addr, data);
+			break;
+		}
+		/* We need to be very careful here.  We implicitly
+		   want to modify a portion of the task_struct, and we
+		   have to be selective about what portions we allow someone
+		   to modify. */
+
+		  ret = -EIO;
+		  if(addr >= (long) &dummy->u_debugreg[0] &&
+		     addr <= (long) &dummy->u_debugreg[7]){
+
+			  if(addr == (long) &dummy->u_debugreg[4]) break;
+			  if(addr == (long) &dummy->u_debugreg[5]) break;
+			  if(addr < (long) &dummy->u_debugreg[4] &&
+			     ((unsigned long) data) >= TASK_SIZE-3) break;
+			  
+			  if(addr == (long) &dummy->u_debugreg[7]) {
+				  data &= ~DR_CONTROL_RESERVED;
+				  for(i=0; i<4; i++)
+					  if ((0x5454 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
+						  goto out_tsk;
+			  }
+
+			  addr -= (long) &dummy->u_debugreg;
+			  addr = addr >> 2;
+			  child->thread.debugreg[addr] = data;
+			  ret = 0;
+		  }
+		  break;
+
+	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
+	case PTRACE_CONT: { /* restart after signal. */
+		long tmp;
+
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			break;
+		if (request == PTRACE_SYSCALL)
+			child->ptrace |= PT_TRACESYS;
+		else
+			child->ptrace &= ~PT_TRACESYS;
+		child->exit_code = data;
+	/* make sure the single step bit is not set. */
+		tmp = get_stack_long(child, EFL_OFFSET);
+		tmp &= ~TRAP_FLAG;
+		put_stack_long(child, EFL_OFFSET,tmp);
+		wake_up_process(child);
+		ret = 0;
+		break;
+	}
+
+/*
+ * make the child exit.  Best I can do is send it a sigkill. 
+ * perhaps it should be put in the status that it wants to 
+ * exit.
+ */
+	case PTRACE_KILL: {
+		long tmp;
+
+		ret = 0;
+		if (child->state == TASK_ZOMBIE)	/* already dead */
+			break;
+		child->exit_code = SIGKILL;
+		/* make sure the single step bit is not set. */
+		tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
+		put_stack_long(child, EFL_OFFSET, tmp);
+		wake_up_process(child);
+		break;
+	}
+
+	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
+		long tmp;
+
+		ret = -EIO;
+		if ((unsigned long) data > _NSIG)
+			break;
+		child->ptrace &= ~PT_TRACESYS;
+		if ((child->ptrace & PT_DTRACE) == 0) {
+			/* Spurious delayed TF traps may occur */
+			child->ptrace |= PT_DTRACE;
+		}
+		tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;
+		put_stack_long(child, EFL_OFFSET, tmp);
+		child->exit_code = data;
+		/* give it a chance to run. */
+		wake_up_process(child);
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_DETACH:
+		/* detach a process that was attached. */
+		ret = ptrace_detach(child, data);
+		break;
+
+	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
+	  	if (!access_ok(VERIFY_WRITE, (unsigned *)data, FRAME_SIZE)) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < sizeof(struct user_regs_struct); i += sizeof(long) ) {
+			__put_user(getreg(child, i),(unsigned long *) data);
+			data += sizeof(long);
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
+		unsigned long tmp;
+	  	if (!access_ok(VERIFY_READ, (unsigned *)data, FRAME_SIZE)) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < sizeof(struct user_regs_struct); i += sizeof(long) ) {
+			__get_user(tmp, (unsigned long *) data);
+			putreg(child, i, tmp);
+			data += sizeof(long);
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_GETFPREGS: { /* Get the child extended FPU state. */
+		if (!access_ok(VERIFY_WRITE, (unsigned *)data,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		ret = get_fpregs((struct user_i387_struct *)data, child);
+		break;
+	}
+
+	case PTRACE_SETFPREGS: { /* Set the child extended FPU state. */
+		if (!access_ok(VERIFY_READ, (unsigned *)data,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		child->used_math = 1;
+		ret = set_fpregs(child, (struct user_i387_struct *)data);
+		break;
+	}
+
+	case PTRACE_SETOPTIONS: {
+		if (data & PTRACE_O_TRACESYSGOOD)
+			child->ptrace |= PT_TRACESYSGOOD;
+		else
+			child->ptrace &= ~PT_TRACESYSGOOD;
+		ret = 0;
+		break;
+	}
+
+	default:
+		ret = -EIO;
+		break;
+	}
+out_tsk:
+	free_task_struct(child);
+out:
+	unlock_kernel();
+	return ret;
+}
+
+asmlinkage void syscall_trace(struct pt_regs *regs)
+{
+	if ((current->ptrace & (PT_PTRACED|PT_TRACESYS)) !=
+			(PT_PTRACED|PT_TRACESYS))
+		return;
+	
+	current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
+					? 0x80 : 0);
+	current->state = TASK_STOPPED;
+	notify_parent(current, SIGCHLD);
+	schedule();
+	/*
+	 * this isn't the same as continuing with a signal, but it will do
+	 * for normal use.  strace only continues with a signal if the
+	 * stopping signal is not SIGTRAP.  -brl
+	 */
+	if (current->exit_code) {
+		send_sig(current->exit_code, current, 1);
+		current->exit_code = 0;
+	}
+}