patch-2.3.10 linux/kernel/ptrace.c

• Lines: 164
• Date: Mon Jul 5 11:30:37 1999
• Orig file: v2.3.9/linux/kernel/ptrace.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.9/linux/kernel/ptrace.c linux/kernel/ptrace.c
@@ -0,0 +1,163 @@
+/*
+ * linux/kernel/ptrace.c
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Common interfaces for "ptrace()" which we do not want
+ * to continually duplicate across every architecture.
+ */
+
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+
+/*
+ * Access another process' address space, one page at a time.
+ */
+static int access_one_page(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long addr, void *buf, int len, int write)
+{
+	pgd_t * pgdir;
+	pmd_t * pgmiddle;
+	pte_t * pgtable;
+	unsigned long page;
+
+repeat:
+	pgdir = pgd_offset(vma->vm_mm, addr);
+	if (pgd_none(*pgdir))
+		goto fault_in_page;
+	if (pgd_bad(*pgdir))
+		goto bad_pgd;
+	pgmiddle = pmd_offset(pgdir, addr);
+	if (pmd_none(*pgmiddle))
+		goto fault_in_page;
+	if (pmd_bad(*pgmiddle))
+		goto bad_pmd;
+	pgtable = pte_offset(pgmiddle, addr);
+	if (!pte_present(*pgtable))
+		goto fault_in_page;
+	page = pte_page(*pgtable);
+	if (MAP_NR(page) >= max_mapnr)
+		return 0;
+	flush_cache_page(vma, addr);
+	{
+		void *src = (void *) (page + (addr & ~PAGE_MASK));
+		void *dst = buf;
+
+		if (write) {
+			dst = src;
+			src = buf;
+		}
+		memcpy(dst, src, len);
+	}
+	flush_page_to_ram(page);
+	return len;
+
+fault_in_page:
+	/* -1: out of memory. 0 - unmapped page */
+	if (handle_mm_fault(tsk, vma, addr, write) > 0)
+		goto repeat;
+	return 0;
+
+bad_pgd:
+	printk("ptrace: bad pgd in '%s' at %08lx (%08lx)\n", tsk->comm, addr, pgd_val(*pgdir));
+	return 0;
+
+bad_pmd:
+	printk("ptrace: bad pmd in '%s' at %08lx (%08lx)\n", tsk->comm, addr, pmd_val(*pgmiddle));
+	return 0;
+}
+
+int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+	int copied;
+	struct vm_area_struct * vma = find_extend_vma(tsk, addr);
+
+	if (!vma)
+		return 0;
+
+	down(&tsk->mm->mmap_sem);
+	copied = 0;
+	for (;;) {
+		unsigned long offset = addr & ~PAGE_MASK;
+		int this_len = PAGE_SIZE - offset;
+		int retval;
+
+		if (this_len > len)
+			this_len = len;
+		retval = access_one_page(tsk, vma, addr, buf, this_len, write);
+		copied += retval;
+		if (retval != this_len)
+			break;
+
+		len -= retval;
+		if (!len)
+			break;
+
+		addr += retval;
+		buf += retval;
+
+		if (addr < vma->vm_end)
+			continue;	
+		if (!vma->vm_next)
+			break;
+		if (vma->vm_next->vm_start != vma->vm_end)
+			break;
+	
+		vma = vma->vm_next;
+	}
+	up(&tsk->mm->mmap_sem);
+	return copied;
+}
+
+int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int len)
+{
+	int copied = 0;
+
+	while (len > 0) {
+		char buf[128];
+		int this_len, retval;
+
+		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+		retval = access_process_vm(tsk, src, buf, this_len, 0);
+		if (!retval) {
+			if (copied)
+				break;
+			return -EIO;
+		}
+		if (copy_to_user(dst, buf, retval))
+			return -EFAULT;
+		copied += retval;
+		src += retval;
+		dst += retval;
+		len -= retval;			
+	}
+	return copied;
+}
+
+int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int len)
+{
+	int copied = 0;
+
+	while (len > 0) {
+		char buf[128];
+		int this_len, retval;
+
+		this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
+		if (copy_from_user(buf, src, this_len))
+			return -EFAULT;
+		retval = access_process_vm(tsk, dst, buf, this_len, 1);
+		if (!retval) {
+			if (copied)
+				break;
+			return -EIO;
+		}
+		copied += retval;
+		src += retval;
+		dst += retval;
+		len -= retval;			
+	}
+	return copied;
+}