From 68baf8e77d4321cfbc072f10ddd5e99c6db4dd51 Mon Sep 17 00:00:00 2001
From: Pavel Emelyanov <xemul@parallels.com>
Date: Tue, 13 Oct 2015 18:06:30 +0300
Subject: [PATCH] criu: Fault injection core

This patch(set) is inspired by similar from Andrey Vagin sent
sime time earlier.

The major idea is to artificially fail criu dump or restore at
specific places and let zdtm tests check whether failed dump
or restore resulted in anything bad.

This particular patch introduces the ability to tell criu "fail
at X point". Each point is specified with a integer constant
and with the next patches there will appear places over the
code checking for specific fail code being set and failing.

Two points are introduced -- early on dump, right after loading
the parasite and right after creation of the root task.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
---
 Makefile.crtools          |  1 +
 cr-dump.c                 |  6 ++++++
 cr-restore.c              |  7 ++++++-
 crtools.c                 |  4 ++++
 fault-injection.c         | 22 ++++++++++++++++++++++
 include/fault-injection.h | 19 +++++++++++++++++++
 6 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 fault-injection.c
 create mode 100644 include/fault-injection.h

diff --git a/Makefile.crtools b/Makefile.crtools
index f55bdb783..ea813e539 100644
--- a/Makefile.crtools
+++ b/Makefile.crtools
@@ -75,6 +75,7 @@ obj-y	+= plugin.o
 obj-y	+= cr-errno.o
 obj-y	+= pie/pie-relocs.o
 obj-y	+= seize.o
+obj-y	+= fault-injection.o
 obj-y	+= pie/util-fd.o
 obj-y	+= pie/util.o
 
diff --git a/cr-dump.c b/cr-dump.c
index 8eaf523c1..fea3be63f 100644
--- a/cr-dump.c
+++ b/cr-dump.c
@@ -81,6 +81,7 @@
 #include "lsm.h"
 #include "seccomp.h"
 #include "seize.h"
+#include "fault-injection.h"
 
 #include "asm/dump.h"
 
@@ -1195,6 +1196,11 @@ static int dump_one_task(struct pstree_item *item)
 		goto err;
 	}
 
+	if (fault_injected(FI_DUMP_EARLY)) {
+		pr_info("fault: CRIU sudden detach\n");
+		BUG();
+	}
+
 	if (root_ns_mask & CLONE_NEWPID && root_item == item) {
 		int pfd;
 
diff --git a/cr-restore.c b/cr-restore.c
index 2c812cda5..a33273c07 100644
--- a/cr-restore.c
+++ b/cr-restore.c
@@ -76,7 +76,7 @@
 #include "security.h"
 #include "lsm.h"
 #include "seccomp.h"
-
+#include "fault-injection.h"
 #include "parasite-syscall.h"
 
 #include "protobuf.h"
@@ -1531,6 +1531,11 @@ static int restore_task_with_children(void *_arg)
 	if (prepare_sigactions() < 0)
 		goto err_fini_mnt;
 
+	if (fault_injected(FI_RESTORE_ROOT_ONLY)) {
+		pr_info("fault: Restore root task failure!\n");
+		BUG();
+	}
+
 	if (create_children_and_session())
 		goto err_fini_mnt;
 
diff --git a/crtools.c b/crtools.c
index ea8b889f0..d3812a18f 100644
--- a/crtools.c
+++ b/crtools.c
@@ -40,6 +40,7 @@
 #include "action-scripts.h"
 #include "security.h"
 #include "irmap.h"
+#include "fault-injection.h"
 
 #include "setproctitle.h"
 
@@ -257,6 +258,9 @@ int main(int argc, char *argv[], char *envp[])
 
 	BUILD_BUG_ON(PAGE_SIZE != PAGE_IMAGE_SIZE);
 
+	if (fault_injection_init())
+		return 1;
+
 	cr_pb_init();
 	if (restrict_uid(getuid(), getgid()))
 		return 1;
diff --git a/fault-injection.c b/fault-injection.c
new file mode 100644
index 000000000..f239fd9db
--- /dev/null
+++ b/fault-injection.c
@@ -0,0 +1,22 @@
+#include <stdlib.h>
+#include "fault-injection.h"
+
+enum faults fi_strategy;
+
+int fault_injection_init()
+{
+	char *val;
+	int strat;
+
+	val = getenv("CRIU_FAULT");
+	if (val == NULL)
+		return 0;
+
+	strat = atoi(val);
+
+	if (strat <= 0 || strat >= FI_MAX)
+		return -1;
+
+	fi_strategy = strat;
+	return 0;
+}
diff --git a/include/fault-injection.h b/include/fault-injection.h
new file mode 100644
index 000000000..989f654b2
--- /dev/null
+++ b/include/fault-injection.h
@@ -0,0 +1,19 @@
+#ifndef __CR_FAULT_INJECTION_H__
+#define __CR_FAULT_INJECTION_H__
+#include <stdbool.h>
+
+enum faults {
+	FI_NONE = 0,
+	FI_DUMP_EARLY,
+	FI_RESTORE_ROOT_ONLY,
+	FI_MAX,
+};
+
+extern enum faults fi_strategy;
+extern int fault_injection_init(void);
+
+static inline bool fault_injected(enum faults f)
+{
+	return fi_strategy == f;
+}
+#endif