[CRIU] [PATCH] criu: x86 -- Drop @ds test from compat mode

[Cyrill Gorcunov]

On Fri, Apr 08, 2016 at 11:06:45AM +0300, Cyrill Gorcunov wrote:
> On Fri, Apr 08, 2016 at 10:02:32AM +0200, Federico Reghenzani wrote:
> >    Nope, I rechecked and it's patched. I tried also to clean, make and
> >    install again, same behaviour.
> 
> OK, thanks a lot! I'll ping you once I figure out what the problem is.

Could you please try this patch instead of previous?

	Cyrill
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>From f8055f8b643526c4246e4a5c3ff9a7ca75dc7d53 Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov at openvz.org>
Date: Wed, 6 Apr 2016 16:41:41 +0300
Subject: [PATCH] criu: x86 -- Use regsets to find if task in compat mode

Reported-by: Federico Reghenzani <federico at reghe.net>
Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
---
 criu/arch/x86/crtools.c           | 28 +++++++++++++---------------
 criu/arch/x86/include/asm/types.h | 10 ++++++++++
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/criu/arch/x86/crtools.c b/criu/arch/x86/crtools.c
index 51eab133f269..e80a5f7d17e8 100644
--- a/criu/arch/x86/crtools.c
+++ b/criu/arch/x86/crtools.c
@@ -55,24 +55,22 @@ void parasite_setup_regs(unsigned long new_ip, void *stack, user_regs_struct_t *
 
 static int task_in_compat_mode(pid_t pid)
 {
-	unsigned long cs, ds;
-
-	errno = 0;
-	cs = ptrace(PTRACE_PEEKUSER, pid, offsetof(user_regs_struct_t, cs), 0);
-	if (errno != 0) {
-		pr_perror("Can't get CS register for %d", pid);
-		return -1;
-	}
-
-	errno = 0;
-	ds = ptrace(PTRACE_PEEKUSER, pid, offsetof(user_regs_struct_t, ds), 0);
-	if (errno != 0) {
-		pr_perror("Can't get DS register for %d", pid);
+	union {
+		user_regs_struct_t	x86_64_regs;
+		user_regs_struct32_t	x86_32_regs;
+	} regs;
+
+	struct iovec iov = {
+		.iov_base	= &regs,
+		.iov_len	= sizeof(regs),
+	};
+
+	if (ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov)) {
+		pr_perror("Can't get registers for %d", pid);
 		return -1;
 	}
 
-	/* It's x86-32 or x32 */
-	return cs != 0x33 || ds == 0x2b;
+	return (iov.iov_len == sizeof(regs.x86_64_regs)) ? 0 : 1;
 }
 
 bool arch_can_dump_task(pid_t pid)
diff --git a/criu/arch/x86/include/asm/types.h b/criu/arch/x86/include/asm/types.h
index c8e76964e430..977c30f9afcb 100644
--- a/criu/arch/x86/include/asm/types.h
+++ b/criu/arch/x86/include/asm/types.h
@@ -91,6 +91,16 @@ typedef struct {
 } user_regs_struct_t;
 
 typedef struct {
+	u32 ebx, ecx, edx, esi, edi, ebp, eax;
+	unsigned short ds, __ds, es, __es;
+	unsigned short fs, __fs, gs, __gs;
+	u32 orig_eax, eip;
+	unsigned short cs, __cs;
+	u32 eflags, esp;
+	unsigned short ss, __ss;
+} user_regs_struct32_t;
+
+typedef struct {
 	unsigned short	cwd;
 	unsigned short	swd;
 	unsigned short	twd;	/* Note this is not the same as
-- 
2.5.5