[PATCH] consolidate sys_ptrace()
The sys_ptrace boilerplate code (everything outside the big switch
statement for the arch-specific requests) is shared by most architectures.
This patch moves it to kernel/ptrace.c and leaves the arch-specific code as
arch_ptrace.
Some architectures have a too different ptrace so we have to exclude them.
They continue to keep their implementations. For sh64 I had to add a
sh64_ptrace wrapper because it does some initialization on the first call.
For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but
SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-By: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 863eee8..5b8dd98 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -406,3 +406,85 @@
return ret;
}
+
+#ifndef __ARCH_SYS_PTRACE
+static int ptrace_get_task_struct(long request, long pid,
+ struct task_struct **childp)
+{
+ struct task_struct *child;
+ int ret;
+
+ /*
+ * Callers use child == NULL as an indication to exit early even
+ * when the return value is 0, so make sure it is non-NULL here.
+ */
+ *childp = NULL;
+
+ if (request == PTRACE_TRACEME) {
+ /*
+ * Are we already being traced?
+ */
+ if (current->ptrace & PT_PTRACED)
+ return -EPERM;
+ ret = security_ptrace(current->parent, current);
+ if (ret)
+ return -EPERM;
+ /*
+ * Set the ptrace bit in the process ptrace flags.
+ */
+ current->ptrace |= PT_PTRACED;
+ return 0;
+ }
+
+ /*
+ * You may not mess with init
+ */
+ if (pid == 1)
+ return -EPERM;
+
+ ret = -ESRCH;
+ read_lock(&tasklist_lock);
+ child = find_task_by_pid(pid);
+ if (child)
+ get_task_struct(child);
+ read_unlock(&tasklist_lock);
+ if (!child)
+ return -ESRCH;
+
+ *childp = child;
+ return 0;
+}
+
+asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+{
+ struct task_struct *child;
+ long ret;
+
+ /*
+ * This lock_kernel fixes a subtle race with suid exec
+ */
+ lock_kernel();
+ ret = ptrace_get_task_struct(request, pid, &child);
+ if (!child)
+ goto out;
+
+ if (request == PTRACE_ATTACH) {
+ ret = ptrace_attach(child);
+ goto out;
+ }
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ ret = arch_ptrace(child, request, addr, data);
+ if (ret < 0)
+ goto out_put_task_struct;
+
+ out_put_task_struct:
+ put_task_struct(child);
+ out:
+ unlock_kernel();
+ return ret;
+}
+#endif /* __ARCH_SYS_PTRACE */