[PATCH] use ptrace_get_task_struct in various places

The ptrace_get_task_struct() helper that I added as part of the ptrace
consolidation is useful in variety of places that currently opencode it.
Switch them to the common helpers.

Add a ptrace_traceme() helper that needs to be explicitly called, and simplify
the ptrace_get_task_struct() interface.  We don't need the request argument
now, and we return the task_struct directly, using ERR_PTR() for error
returns.  It's a bit more code in the callers, but we have two sane routines
that do one thing well now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 29 deletions

diff --git a/arch/sparc/kernel/ptrace.c b/arch/sparc/kernel/ptrace.c
index 475c4c1..fc470c0 100644
--- a/arch/sparc/kernel/ptrace.c
+++ b/arch/sparc/kernel/ptrace.c
@@ -286,40 +286,17 @@ asmlinkage void do_ptrace(struct pt_regs *regs)
 			       s, (int) request, (int) pid, addr, data, addr2);
 	}
 #endif
-	if (request == PTRACE_TRACEME) {
-		int my_ret;
-
-		/* are we already being traced? */
-		if (current->ptrace & PT_PTRACED) {
-			pt_error_return(regs, EPERM);
-			goto out;
-		}
-		my_ret = security_ptrace(current->parent, current);
-		if (my_ret) {
-			pt_error_return(regs, -my_ret);
-			goto out;
-		}
 
-		/* set the ptrace bit in the process flags. */
-		current->ptrace |= PT_PTRACED;
+	if (request == PTRACE_TRACEME) {
+		ret = ptrace_traceme();
 		pt_succ_return(regs, 0);
 		goto out;
 	}
-#ifndef ALLOW_INIT_TRACING
-	if (pid == 1) {
-		/* Can't dork with init. */
-		pt_error_return(regs, EPERM);
-		goto out;
-	}
-#endif
-	read_lock(&tasklist_lock);
-	child = find_task_by_pid(pid);
-	if (child)
-		get_task_struct(child);
-	read_unlock(&tasklist_lock);
 
-	if (!child) {
-		pt_error_return(regs, ESRCH);
+	child = ptrace_get_task_struct(pid);
+	if (IS_ERR(child)) {
+		ret = PTR_ERR(child);
+		pt_error_return(regs, -ret);
 		goto out;
 	}