ptrace: add ability to retrieve signals without removing from a queue (v4)

[karo-tx-linux.git] / kernel / ptrace.c

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index acbd28424d812040e060a82ae2d6f28e156e5fe1..17ae54da0ec2efb010184c38daf1c43953a6745c 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -24,6 +24,7 @@
 #include <linux/regset.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/cn_proc.h>
+#include <linux/compat.h>
 
 
 static int ptrace_trapping_sleep_fn(void *flags)
@@ -618,6 +619,81 @@ static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
        return error;
 }
 
+static int ptrace_peek_siginfo(struct task_struct *child,
+                               unsigned long addr,
+                               unsigned long data)
+{
+       struct ptrace_peeksiginfo_args arg;
+       struct sigpending *pending;
+       struct sigqueue *q;
+       int ret, i;
+
+       ret = copy_from_user(&arg, (void __user *) addr,
+                               sizeof(struct ptrace_peeksiginfo_args));
+       if (ret)
+               return -EFAULT;
+
+       if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
+               return -EINVAL; /* unknown flags */
+
+       if (arg.nr < 0)
+               return -EINVAL;
+
+       if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
+               pending = &child->signal->shared_pending;
+       else
+               pending = &child->pending;
+
+       for (i = 0; i < arg.nr; ) {
+               siginfo_t info;
+               s32 off = arg.off + i;
+
+               spin_lock_irq(&child->sighand->siglock);
+               list_for_each_entry(q, &pending->list, list) {
+                       if (!off--) {
+                               copy_siginfo(&info, &q->info);
+                               break;
+                       }
+               }
+               spin_unlock_irq(&child->sighand->siglock);
+
+               if (off >= 0) /* beyond the end of the list */
+                       break;
+
+#ifdef CONFIG_COMPAT
+               if (unlikely(is_compat_task())) {
+                       compat_siginfo_t __user *uinfo = compat_ptr(data);
+
+                       ret = copy_siginfo_to_user32(uinfo, &info);
+                       ret |= __put_user(info.si_code, &uinfo->si_code);
+               } else
+#endif
+               {
+                       siginfo_t __user *uinfo = (siginfo_t __user *) data;
+
+                       ret = copy_siginfo_to_user(uinfo, &info);
+                       ret |= __put_user(info.si_code, &uinfo->si_code);
+               }
+
+               if (ret) {
+                       ret = -EFAULT;
+                       break;
+               }
+
+               data += sizeof(siginfo_t);
+               i++;
+
+               if (signal_pending(current))
+                       break;
+
+               cond_resched();
+       }
+
+       if (i > 0)
+               return i;
+
+       return ret;
+}
 
 #ifdef PTRACE_SINGLESTEP
 #define is_singlestep(request)         ((request) == PTRACE_SINGLESTEP)
@@ -748,6 +824,10 @@ int ptrace_request(struct task_struct *child, long request,
                ret = put_user(child->ptrace_message, datalp);
                break;
 
+       case PTRACE_PEEKSIGINFO:
+               ret = ptrace_peek_siginfo(child, addr, data);
+               break;
+
        case PTRACE_GETSIGINFO:
                ret = ptrace_getsiginfo(child, &siginfo);
                if (!ret)