patch-1.3.94 linux/arch/m68k/kernel/ptrace.c

• Lines: 535
• Date: Fri Apr 5 20:40:35 1996
• Orig file: v1.3.93/linux/arch/m68k/kernel/ptrace.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/kernel/ptrace.c linux/arch/m68k/kernel/ptrace.c
@@ -0,0 +1,534 @@
+/*
+ *  linux/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
+ *
+ * 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/errno.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+/* determines which bits in the SR the user has access to. */
+/* 1 = access 0 = no access */
+#define SR_MASK 0x001f
+
+/* sets the trace bits. */
+#define TRACE_BITS 0x8000
+
+/* Find the stack offset for a register, relative to tss.esp0. */
+#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
+#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
+			 - sizeof(struct switch_stack))
+/* Mapping from PT_xxx to the stack offset at which the register is
+   saved.  Notice that usp has no stack-slot and needs to be treated
+   specially (see get_reg/put_reg below). */
+static int regoff[] = {
+	PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
+	PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
+	PT_REG(a1), SW_REG(a2), SW_REG(a3), SW_REG(a4),
+	SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
+	PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
+};
+
+/* change a pid into a task struct. */
+static inline struct task_struct * get_task(int pid)
+{
+	int i;
+
+	for (i = 1; i < NR_TASKS; i++) {
+		if (task[i] != NULL && (task[i]->pid == pid))
+			return task[i];
+	}
+	return NULL;
+}
+
+/*
+ * Get contents of register REGNO in task TASK.
+ */
+static inline long get_reg(struct task_struct *task, int regno)
+{
+	unsigned long *addr;
+
+	if (regno == PT_USP)
+		addr = &task->tss.usp;
+	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
+		addr = (unsigned long *)(task->tss.esp0 + regoff[regno]);
+	else
+		return 0;
+	return *addr;
+}
+
+/*
+ * Write contents of register REGNO in task TASK.
+ */
+static inline int put_reg(struct task_struct *task, int regno,
+			  unsigned long data)
+{
+	unsigned long *addr;
+
+	if (regno == PT_USP)
+		addr = &task->tss.usp;
+	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
+		addr = (unsigned long *) (task->tss.esp0 + regoff[regno]);
+	else
+		return -1;
+	*addr = data;
+	return 0;
+}
+
+/*
+ * This routine gets a long from any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ *
+ */
+static unsigned long get_long(struct task_struct * tsk, 
+	struct vm_area_struct * vma, unsigned long addr)
+{
+	pgd_t * pgdir;
+	pmd_t * pgmiddle;
+	pte_t * pgtable;
+	unsigned long page;
+
+repeat:
+	pgdir = pgd_offset(vma->vm_mm, addr);
+	if (pgd_none(*pgdir)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	if (pgd_bad(*pgdir)) {
+		printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
+		pgd_clear(pgdir);
+		return 0;
+	}
+	pgmiddle = pmd_offset(pgdir,addr);
+	if (pmd_none(*pgmiddle)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	if (pmd_bad(*pgmiddle)) {
+		printk("ptrace: bad page directory %08lx\n",
+		       pmd_val(*pgmiddle));
+		pmd_clear(pgmiddle);
+		return 0;
+	}
+	pgtable = pte_offset(pgmiddle, addr);
+	if (!pte_present(*pgtable)) {
+		do_no_page(tsk, vma, addr, 0);
+		goto repeat;
+	}
+	page = pte_page(*pgtable);
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	if (page >= high_memory)
+		return 0;
+	page += addr & ~PAGE_MASK;
+	return *(unsigned long *) page;
+}
+
+/*
+ * This routine puts a long into any process space by following the page
+ * tables. NOTE! You should check that the long isn't on a page boundary,
+ * and that it is in the task area before calling this: this routine does
+ * no checking.
+ *
+ * Now keeps R/W state of page so that a text page stays readonly
+ * even if a debugger scribbles breakpoints into it.  -M.U-
+ */
+static void put_long(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long addr,
+	unsigned long data)
+{
+	pgd_t *pgdir;
+	pmd_t *pgmiddle;
+	pte_t *pgtable;
+	unsigned long page;
+		
+repeat:
+	pgdir = pgd_offset(vma->vm_mm, addr);
+	if (!pgd_present(*pgdir)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	if (pgd_bad(*pgdir)) {
+		printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
+		pgd_clear(pgdir);
+		return;
+	}
+	pgmiddle = pmd_offset(pgdir,addr);
+	if (pmd_none(*pgmiddle)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	if (pmd_bad(*pgmiddle)) {
+		printk("ptrace: bad page directory %08lx\n",
+		       pmd_val(*pgmiddle));
+		pmd_clear(pgmiddle);
+		return;
+	}
+	pgtable = pte_offset(pgmiddle, addr);
+	if (!pte_present(*pgtable)) {
+		do_no_page(tsk, vma, addr, 1);
+		goto repeat;
+	}
+	page = pte_page(*pgtable);
+	if (!pte_write(*pgtable)) {
+		do_wp_page(tsk, vma, addr, 2);
+		goto repeat;
+	}
+/* this is a hack for non-kernel-mapped video buffers and similar */
+	if (page < high_memory) {
+		*(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
+	}
+/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
+/* this should also re-instate whatever read-only mode there was before */
+	*pgtable = pte_mkdirty(mk_pte(page, vma->vm_page_prot));
+	flush_tlb_all();
+}
+
+static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)
+{
+	struct vm_area_struct * vma;
+
+	addr &= PAGE_MASK;
+	vma = find_vma(tsk,addr);
+	if (!vma)
+		return NULL;
+	if (vma->vm_start <= addr)
+		return vma;
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		return NULL;
+	if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)
+		return NULL;
+	vma->vm_offset -= vma->vm_start - addr;
+	vma->vm_start = addr;
+	return vma;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls get_long() to read a long.
+ */
+static int read_long(struct task_struct * tsk, unsigned long addr,
+	unsigned long * result)
+{
+	struct vm_area_struct * vma = find_extend_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
+		unsigned long low,high;
+		struct vm_area_struct * vma_low = vma;
+
+		if (addr + sizeof(long) >= vma->vm_end) {
+			vma_low = vma->vm_next;
+			if (!vma_low || vma_low->vm_start != vma->vm_end)
+				return -EIO;
+		}
+		high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
+		low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
+		switch (addr & (sizeof(long)-1)) {
+			case 3:
+				low >>= 8;
+				low |= high << 24;
+				break;
+			case 2:
+				low >>= 16;
+				low |= high << 16;
+				break;
+			case 1:
+				low >>= 24;
+				low |= high << 8;
+				break;
+		}
+		*result = low;
+	} else
+		*result = get_long(tsk, vma,addr);
+	return 0;
+}
+
+/*
+ * This routine checks the page boundaries, and that the offset is
+ * within the task area. It then calls put_long() to write a long.
+ */
+static int write_long(struct task_struct * tsk, unsigned long addr,
+	unsigned long data)
+{
+	struct vm_area_struct * vma = find_extend_vma(tsk, addr);
+
+	if (!vma)
+		return -EIO;
+	if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
+		unsigned long low,high;
+		struct vm_area_struct * vma_low = vma;
+
+		if (addr + sizeof(long) >= vma->vm_end) {
+			vma_low = vma->vm_next;
+			if (!vma_low || vma_low->vm_start != vma->vm_end)
+				return -EIO;
+		}
+		high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
+		low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
+		switch (addr & (sizeof(long)-1)) {
+			case 0: /* shouldn't happen, but safety first */
+				high = data;
+				break;
+			case 3:
+				low &= 0x000000ff;
+				low |= data << 8;
+				high &= ~0xff;
+				high |= data >> 24;
+				break;
+			case 2:
+				low &= 0x0000ffff;
+				low |= data << 16;
+				high &= ~0xffff;
+				high |= data >> 16;
+				break;
+			case 1:
+				low &= 0x00ffffff;
+				low |= data << 24;
+				high &= ~0xffffff;
+				high |= data >> 8;
+				break;
+		}
+		put_long(tsk, vma,addr & ~(sizeof(long)-1),high);
+		put_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1),low);
+	} else
+		put_long(tsk, vma,addr,data);
+	return 0;
+}
+
+asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
+{
+	struct task_struct *child;
+	struct user * dummy;
+
+	dummy = NULL;
+
+	if (request == PTRACE_TRACEME) {
+		/* are we already being traced? */
+		if (current->flags & PF_PTRACED)
+			return -EPERM;
+		/* set the ptrace bit in the process flags. */
+		current->flags |= PF_PTRACED;
+		return 0;
+	}
+	if (pid == 1)		/* you may not mess with init */
+		return -EPERM;
+	if (!(child = get_task(pid)))
+		return -ESRCH;
+	if (request == PTRACE_ATTACH) {
+		if (child == current)
+			return -EPERM;
+		if ((!child->dumpable ||
+		    (current->uid != child->euid) ||
+		    (current->uid != child->uid) ||
+	 	    (current->gid != child->egid) ||
+	 	    (current->gid != child->gid)) && !suser())
+			return -EPERM;
+		/* the same process cannot be attached many times */
+		if (child->flags & PF_PTRACED)
+			return -EPERM;
+		child->flags |= PF_PTRACED;
+		if (child->p_pptr != current) {
+			REMOVE_LINKS(child);
+			child->p_pptr = current;
+			SET_LINKS(child);
+		}
+		send_sig(SIGSTOP, child, 1);
+		return 0;
+	}
+	if (!(child->flags & PF_PTRACED))
+		return -ESRCH;
+	if (child->state != TASK_STOPPED) {
+		if (request != PTRACE_KILL)
+			return -ESRCH;
+	}
+	if (child->p_pptr != current)
+		return -ESRCH;
+
+	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 res;
+
+			res = read_long(child, addr, &tmp);
+			if (res < 0)
+				return res;
+			res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
+			if (!res)
+				put_user(tmp, (unsigned long *) data);
+			return res;
+		}
+
+	/* read the word at location addr in the USER area. */
+		case PTRACE_PEEKUSR: {
+			unsigned long tmp;
+			int res;
+			
+			if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
+				return -EIO;
+			
+			res = verify_area(VERIFY_WRITE, (void *) data,
+					  sizeof(long));
+			if (res)
+				return res;
+			tmp = 0;  /* Default return condition */
+			addr = addr >> 2; /* temporary hack. */
+			if (addr < 19) {
+				tmp = get_reg(child, addr);
+				if (addr == PT_SR)
+					tmp >>= 16;
+			}
+			else if (addr >= 21 && addr < 49)
+				tmp = child->tss.fp[addr - 21];
+			else
+				return -EIO;
+			put_user(tmp,(unsigned long *) data);
+			return 0;
+		}
+
+      /* 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:
+			return write_long(child,addr,data);
+
+		case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
+			if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
+				return -EIO;
+
+			addr = addr >> 2; /* temporary hack. */
+			    
+			if (addr == PT_ORIG_D0)
+				return -EIO;
+			if (addr == PT_SR) {
+				data &= SR_MASK;
+				data <<= 16;
+				data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
+			}
+			if (addr < 19) {
+				if (put_reg(child, addr, data))
+					return -EIO;
+				return 0;
+			}
+			if (addr >= 21 && addr < 48)
+			{
+				child->tss.fp[addr - 21] = data;
+				return 0;
+			}
+			return -EIO;
+
+		case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
+		case PTRACE_CONT: { /* restart after signal. */
+			long tmp;
+
+			if ((unsigned long) data >= NSIG)
+				return -EIO;
+			if (request == PTRACE_SYSCALL)
+				child->flags |= PF_TRACESYS;
+			else
+				child->flags &= ~PF_TRACESYS;
+			child->exit_code = data;
+			wake_up_process(child);
+			/* make sure the single step bit is not set. */
+			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
+			put_reg(child, PT_SR, tmp);
+			return 0;
+		}
+
+/*
+ * 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;
+
+			if (child->state == TASK_ZOMBIE) /* already dead */
+				return 0;
+			wake_up_process(child);
+			child->exit_code = SIGKILL;
+	/* make sure the single step bit is not set. */
+			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
+			put_reg(child, PT_SR, tmp);
+			return 0;
+		}
+
+		case PTRACE_SINGLESTEP: {  /* set the trap flag. */
+			long tmp;
+
+			if ((unsigned long) data >= NSIG)
+				return -EIO;
+			child->flags &= ~PF_TRACESYS;
+			tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
+			put_reg(child, PT_SR, tmp);
+
+			wake_up_process(child);
+			child->exit_code = data;
+	/* give it a chance to run. */
+			return 0;
+		}
+
+		case PTRACE_DETACH: { /* detach a process that was attached. */
+			long tmp;
+
+			if ((unsigned long) data >= NSIG)
+				return -EIO;
+			child->flags &= ~(PF_PTRACED|PF_TRACESYS);
+			wake_up_process(child);
+			child->exit_code = data;
+			REMOVE_LINKS(child);
+			child->p_pptr = child->p_opptr;
+			SET_LINKS(child);
+			/* make sure the single step bit is not set. */
+			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
+			put_reg(child, PT_SR, tmp);
+			return 0;
+		}
+
+		default:
+			return -EIO;
+	}
+}
+
+asmlinkage void syscall_trace(void)
+{
+	if ((current->flags & (PF_PTRACED|PF_TRACESYS))
+			!= (PF_PTRACED|PF_TRACESYS))
+		return;
+	current->exit_code = SIGTRAP;
+	current->state = TASK_STOPPED;
+	notify_parent(current);
+	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)
+		current->signal |= (1 << (current->exit_code - 1));
+	current->exit_code = 0;
+	return;
+}