[PATCH -mm 08/43] compat_ptrace_request

[Roland McGrath]

This adds a compat_ptrace_request that is the analogue of ptrace_request
for the things that 32-on-64 ptrace implementations can share in common.
So far there are just a couple of requests handled generically.

Signed-off-by: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 include/linux/compat.h |    4 ++++
 kernel/ptrace.c        |   38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index ba29d4c..e70a2a1 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -271,5 +271,9 @@ asmlinkage long compat_sys_signalfd(int ufd,
 asmlinkage long compat_sys_timerfd(int ufd, int clockid, int flags,
 				const struct compat_itimerspec __user *utmr);
 
+extern int compat_ptrace_request(struct task_struct *child,
+				 compat_long_t request,
+				 compat_ulong_t addr, compat_ulong_t data);
+
 #endif /* CONFIG_COMPAT */
 #endif /* _LINUX_COMPAT_H */
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index e521042..bc1a764 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -605,3 +605,41 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
 	copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
 	return (copied == sizeof(data)) ? 0 : -EIO;
 }
+
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+int compat_ptrace_request(struct task_struct *child, compat_long_t request,
+			  compat_ulong_t addr, compat_ulong_t data)
+{
+	compat_ulong_t __user *datap = compat_ptr(data);
+	compat_ulong_t word;
+	int ret;
+
+	switch (request) {
+	case PTRACE_PEEKTEXT:
+	case PTRACE_PEEKDATA:
+		ret = access_process_vm(child, addr, &word, sizeof(word), 0);
+		if (ret != sizeof(word))
+			ret = -EIO;
+		else
+			ret = put_user(word, datap);
+		break;
+
+	case PTRACE_POKETEXT:
+	case PTRACE_POKEDATA:
+		ret = access_process_vm(child, addr, &data, sizeof(data), 1);
+		ret = (ret != sizeof(data) ? -EIO : 0);
+		break;
+
+	case PTRACE_GETEVENTMSG:
+		ret = put_user((compat_ulong_t) child->ptrace_message, datap);
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+	}
+
+	return ret;
+}
+#endif	/* CONFIG_COMPAT */
-- 
1.5.3.6

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