* runtime/uprobes/uprobes.c: Added static copy of

access_process_vm(), for kernels that don't export it.

1 files changed, 62 insertions, 0 deletions

diff --git a/runtime/uprobes/uprobes.c b/runtime/uprobes/uprobes.c
index 50930709..005ca919 100644
--- a/runtime/uprobes/uprobes.c
+++ b/runtime/uprobes/uprobes.c
@@ -42,8 +42,14 @@
 
 #define MAX_SSOL_SLOTS		1024
 
+#ifdef NO_ACCESS_PROCESS_VM_EXPORT
+static int __access_process_vm(struct task_struct *tsk, unsigned long addr,
+	void *buf, int len, int write);
+#define access_process_vm __access_process_vm
+#else
 extern int access_process_vm(struct task_struct *tsk, unsigned long addr,
 	void *buf, int len, int write);
+#endif
 static int utask_fake_quiesce(struct uprobe_task *utask);
 static void uprobe_release_ssol_vma(struct uprobe_process *uproc);
 
@@ -2267,5 +2273,61 @@ static void zap_uretprobe_instances(struct uprobe *u,
 }
 #endif /* CONFIG_URETPROBES */
 
+#ifdef NO_ACCESS_PROCESS_VM_EXPORT
+/*
+ * Some kernel versions export everything that uprobes.ko needs except
+ * access_process_vm, so we copied and pasted it here.  Fortunately,
+ * everything it calls is exported.
+ */
+#include <linux/pagemap.h>
+#include <asm/cacheflush.h>
+static int __access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	struct page *page;
+	void *old_buf = buf;
+
+	mm = get_task_mm(tsk);
+	if (!mm)
+		return 0;
+
+	down_read(&mm->mmap_sem);
+	/* ignore errors, just check how much was sucessfully transfered */
+	while (len) {
+		int bytes, ret, offset;
+		void *maddr;
+
+		ret = get_user_pages(tsk, mm, addr, 1,
+				write, 1, &page, &vma);
+		if (ret <= 0)
+			break;
+
+		bytes = len;
+		offset = addr & (PAGE_SIZE-1);
+		if (bytes > PAGE_SIZE-offset)
+			bytes = PAGE_SIZE-offset;
+
+		maddr = kmap(page);
+		if (write) {
+			copy_to_user_page(vma, page, addr,
+					  maddr + offset, buf, bytes);
+			set_page_dirty_lock(page);
+		} else {
+			copy_from_user_page(vma, page, addr,
+					    buf, maddr + offset, bytes);
+		}
+		kunmap(page);
+		page_cache_release(page);
+		len -= bytes;
+		buf += bytes;
+		addr += bytes;
+	}
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+
+	return buf - old_buf;
+}
+#endif
 #include "uprobes_arch.c"
 MODULE_LICENSE("GPL");