patch-2.3.99-pre8 linux/arch/s390/kernel/ptrace.c

• Lines: 396
• Date: Fri May 12 11:41:45 2000
• Orig file: v2.3.99-pre7/linux/arch/s390/kernel/ptrace.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre7/linux/arch/s390/kernel/ptrace.c linux/arch/s390/kernel/ptrace.c
@@ -0,0 +1,395 @@
+/*
+ *  arch/s390/kernel/ptrace.c
+ *
+ *  S390 version
+ *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *
+ *  Based on PowerPC version 
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Derived from "arch/m68k/kernel/ptrace.c"
+ *  Copyright (C) 1994 by Hamish Macdonald
+ *  Taken from linux/kernel/ptrace.c and modified for M680x0.
+ *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
+ *
+ * Modified by Cort Dougan (cort@cs.nmt.edu) 
+ *
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file README.legal in the main directory of
+ * this archive for more details.
+ */
+
+#include <stddef.h>
+#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/segment.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+
+void FixPerRegisters(struct task_struct *task)
+{
+	struct pt_regs *regs = task->thread.regs;
+	per_struct *per_info=
+			(per_struct *)&task->thread.per_info;
+
+	per_info->control_regs.bits.em_instruction_fetch=
+	per_info->single_step|per_info->instruction_fetch;
+	
+	if(per_info->single_step)
+	{
+		per_info->control_regs.bits.starting_addr=0;
+		per_info->control_regs.bits.ending_addr=0x7fffffffUL;
+	}
+	else
+	{
+		per_info->control_regs.bits.starting_addr=
+		per_info->starting_addr;
+		per_info->control_regs.bits.ending_addr=
+		per_info->ending_addr;
+	}
+	/* if any of the control reg tracing bits are on 
+	   we switch on per in the psw */
+	if(per_info->control_regs.words.cr[0]&PER_EM_MASK)
+		regs->psw.mask |=PSW_PER_MASK;
+	else
+		regs->psw.mask &= ~PSW_PER_MASK;
+	if(per_info->control_regs.bits.storage_alt_space_ctl)
+		task->thread.user_seg|=USER_STD_MASK;
+	else
+		task->thread.user_seg&=~USER_STD_MASK;
+}
+
+void set_single_step(struct task_struct *task)
+{
+	per_struct *per_info=
+			(per_struct *)&task->thread.per_info;	
+	
+	per_info->single_step=1;  /* Single step */
+	FixPerRegisters(task);
+}
+
+void clear_single_step(struct task_struct *task)
+{
+	per_struct *per_info=
+			(per_struct *)&task->thread.per_info;
+
+	per_info->single_step=0;
+	FixPerRegisters(task);
+}
+
+int ptrace_usercopy(addr_t realuseraddr,addr_t copyaddr,int len,int tofromuser,int writeuser,u32 mask)
+{
+	u32  tempuser;
+	int  retval=0;
+	
+	if(writeuser&&realuseraddr==(addr_t)NULL)
+		return(0);
+	if(mask!=0xffffffff)
+	{
+		tempuser=*((u32 *)realuseraddr);
+		if(!writeuser)
+		{
+			tempuser&=mask;
+			realuseraddr=(addr_t)&tempuser;
+		}
+	}
+	if(tofromuser)
+	{
+		if(writeuser)
+		{
+			retval=copy_from_user((void *)realuseraddr,(void *)copyaddr,len);
+		}
+		else
+		{
+			if(realuseraddr==(addr_t)NULL)
+				retval=(clear_user((void *)copyaddr,len)==-EFAULT ? -EIO:0);
+			else
+				retval=(copy_to_user((void *)copyaddr,(void *)realuseraddr,len)==-EFAULT ? -EIO:0);
+		}      
+	}
+	else
+	{
+		if(writeuser)
+			memcpy((void *)realuseraddr,(void *)copyaddr,len);
+		else
+			memcpy((void *)copyaddr,(void *)realuseraddr,len);
+	}
+	if(mask!=0xffffffff&&writeuser)
+			(*((u32 *)realuseraddr))=(((*((u32 *)realuseraddr))&mask)|(tempuser&~mask));
+	return(retval);
+}
+
+int copy_user(struct task_struct *task,saddr_t useraddr,addr_t copyaddr,int len,int tofromuser,int writingtouser)
+{
+	int copylen=0,copymax;
+	addr_t  realuseraddr;
+	saddr_t enduseraddr=useraddr+len;
+	
+	u32 mask;
+
+	if (useraddr < 0 || enduseraddr > sizeof(struct user)||
+	   (useraddr < PT_ENDREGS && (useraddr&3))||
+	   (enduseraddr < PT_ENDREGS && (enduseraddr&3)))
+		return (-EIO);
+	while(len>0)
+	{
+		mask=0xffffffff;
+		if(useraddr<PT_FPC)
+		{
+			realuseraddr=(addr_t)&(((u8 *)task->thread.regs)[useraddr]);
+			if(useraddr<PT_PSWMASK)
+			{
+				copymax=PT_PSWMASK;
+			}
+			else if(useraddr<(PT_PSWMASK+4))
+			{
+				copymax=(PT_PSWMASK+4);
+				if(writingtouser)
+					mask=PSW_MASK_DEBUGCHANGE;
+			}
+			else if(useraddr<(PT_PSWADDR+4))
+			{
+				copymax=PT_PSWADDR+4;
+				mask=PSW_ADDR_DEBUGCHANGE;
+			}
+			else
+				copymax=PT_FPC;
+			
+		}
+		else if(useraddr<(PT_FPR15_LO+4))
+		{
+			copymax=(PT_FPR15_LO+4);
+			realuseraddr=(addr_t)&(((u8 *)&task->thread.fp_regs)[useraddr-PT_FPC]);
+		}
+		else if(useraddr<sizeof(user_regs_struct))
+		{
+			copymax=sizeof(user_regs_struct);
+			realuseraddr=(addr_t)&(((u8 *)&task->thread.per_info)[useraddr-PT_CR_9]);
+		}
+		else 
+		{
+			copymax=sizeof(struct user);
+			realuseraddr=(addr_t)NULL;
+		}
+		copylen=copymax-useraddr;
+		copylen=(copylen>len ? len:copylen);
+		if(ptrace_usercopy(realuseraddr,copyaddr,copylen,tofromuser,writingtouser,mask))
+			return (-EIO);
+		copyaddr+=copylen;
+		len-=copylen;
+		useraddr+=copylen;
+	}
+	FixPerRegisters(task);
+	return(0);
+}
+
+asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
+{
+	struct task_struct *child;
+	int ret = -EPERM;
+	unsigned long flags;
+	unsigned long tmp;
+	int copied;
+	ptrace_area   parea; 
+
+	lock_kernel();
+	if (request == PTRACE_TRACEME) 
+	{
+		/* are we already being traced? */
+		if (current->flags & PF_PTRACED)
+			goto out;
+		/* set the ptrace bit in the process flags. */
+		current->flags |= PF_PTRACED;
+		ret = 0;
+		goto out;
+	}
+	ret = -ESRCH;
+	read_lock(&tasklist_lock);
+	child = find_task_by_pid(pid);
+	read_unlock(&tasklist_lock);
+	if (!child)
+		goto out;
+	ret = -EPERM;
+	if (pid == 1)		/* you may not mess with init */
+		goto out;
+	if (request == PTRACE_ATTACH) 
+	{
+		if (child == current)
+			goto out;
+		if ((!child->dumpable ||
+		     (current->uid != child->euid) ||
+		     (current->uid != child->suid) ||
+		     (current->uid != child->uid) ||
+		     (current->gid != child->egid) ||
+		     (current->gid != child->sgid)) && !capable(CAP_SYS_PTRACE))
+			goto out;
+		/* the same process cannot be attached many times */
+		if (child->flags & PF_PTRACED)
+			goto out;
+		child->flags |= PF_PTRACED;
+
+		write_lock_irqsave(&tasklist_lock, flags);
+		if (child->p_pptr != current) 
+		{
+			REMOVE_LINKS(child);
+			child->p_pptr = current;
+			SET_LINKS(child);
+		}
+		write_unlock_irqrestore(&tasklist_lock, flags);
+
+		send_sig(SIGSTOP, child, 1);
+		ret = 0;
+		goto out;
+	}
+	ret = -ESRCH;
+	// printk("child=%lX child->flags=%lX",child,child->flags);
+	if (!(child->flags & PF_PTRACED))
+		goto out;
+	if (child->state != TASK_STOPPED) 
+	{
+		if (request != PTRACE_KILL)
+			goto out;
+	}
+	if (child->p_pptr != current)
+		goto out;
+
+	switch (request) 
+	{
+		/* If I and D space are separate, these will need to be fixed. */
+	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
+	case PTRACE_PEEKDATA: 
+		copied = access_process_vm(child,ADDR_BITS_REMOVE(addr), &tmp, sizeof(tmp), 0);
+		ret = -EIO;
+		if (copied != sizeof(tmp))
+			goto out;
+		ret = put_user(tmp,(unsigned long *) data);
+		goto out;
+
+		/* read the word at location addr in the USER area. */
+	case PTRACE_PEEKUSR:
+		ret=copy_user(child,addr,data,sizeof(unsigned long),1,0);
+		break;
+
+		/* If 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_BITS_REMOVE(addr), &data, sizeof(data), 1) == sizeof(data))
+			goto out;
+		ret = -EIO;
+		goto out;
+		break;
+
+	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
+		ret=copy_user(child,addr,(addr_t)&data,sizeof(unsigned long),0,1);
+		break;
+
+	case PTRACE_SYSCALL: 	/* continue and stop at next (return from) syscall */
+	case PTRACE_CONT: 	 /* restart after signal. */
+		ret = -EIO;
+		if ((unsigned long) data >= _NSIG)
+			break;
+		if (request == PTRACE_SYSCALL)
+			child->flags |= PF_TRACESYS;
+		else
+			child->flags &= ~PF_TRACESYS;
+		child->exit_code = data;
+		/* make sure the single step bit is not set. */
+		clear_single_step(child);
+		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:
+		ret = 0;
+		if (child->state == TASK_ZOMBIE) /* already dead */
+			break;
+		child->exit_code = SIGKILL;
+		clear_single_step(child);
+		wake_up_process(child);
+		/* make sure the single step bit is not set. */
+		break;
+
+	case PTRACE_SINGLESTEP:  /* set the trap flag. */
+		ret = -EIO;
+		if ((unsigned long) data >= _NSIG)
+			break;
+		child->flags &= ~PF_TRACESYS;
+		child->exit_code = data;
+		set_single_step(child);
+		/* give it a chance to run. */
+		wake_up_process(child);
+		ret = 0;
+		break;
+
+	case PTRACE_DETACH:  /* detach a process that was attached. */
+		ret = -EIO;
+		if ((unsigned long) data >= _NSIG)
+			break;
+		child->flags &= ~(PF_PTRACED|PF_TRACESYS);
+		child->exit_code = data;
+		write_lock_irqsave(&tasklist_lock, flags);
+		REMOVE_LINKS(child);
+		child->p_pptr = child->p_opptr;
+		SET_LINKS(child);
+		write_unlock_irqrestore(&tasklist_lock, flags);
+		/* make sure the single step bit is not set. */
+		clear_single_step(child);
+		wake_up_process(child);
+		ret = 0;
+		break;
+	case PTRACE_PEEKUSR_AREA:
+	case PTRACE_POKEUSR_AREA:
+		if((ret=copy_from_user(&parea,(void *)addr,sizeof(parea)))==0)  
+		   ret=copy_user(child,parea.kernel_addr,parea.process_addr,
+				 parea.len,1,(request==PTRACE_POKEUSR_AREA));
+		break;
+	default:
+		ret = -EIO;
+		break;
+	}
+ out:
+	unlock_kernel();
+	return ret;
+}
+
+asmlinkage void syscall_trace(void)
+{
+	lock_kernel();
+	if ((current->flags & (PF_PTRACED|PF_TRACESYS))
+	    != (PF_PTRACED|PF_TRACESYS))
+		goto out;
+	current->exit_code = SIGTRAP;
+	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;
+	}
+ out:
+	unlock_kernel();
+}