[Fault-injection-developer] [RFC] [PATCH] code segment patch

[Zhuang, L. <lou...@in...>]

Dear all,
	I ask for your comments again. ;-)
following patch is the code segment implementation with a mock code segment
sample. you can try it by following steps:
1. 'bk pull http://fault-injection.bkbits.net/linux-2.5'
2. install the kernel and modules (NOTE, you need new modutils by Rusty
Russell)
3. modprobe fi_mock_cs
4. modprobe fi_mock_interceptor
5. mount -tsysfs none /sys
6. add a trigger (echo "add test MMIO 1000 c 0 0 0 0 0 0 0 1 4 0" >
/sys/fault-injection/triggers/ctl )
7. attach trigger with code_segment (echo "test" >
/sys/fault-injection/code-segments/mock/trigger)
8. trigger the mock interception (echo "1" >
/sys/fault-injection/triggers/test/trip)
  - Louis

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.918   -> 1.922  
#	drivers/char/fi/pf/pf.c	1.17    -> 1.18   
#	   arch/i386/Kconfig	1.25    -> 1.26   
#	drivers/char/fi/Makefile	1.6     -> 1.7    
#	drivers/char/fi/fi_core.c	1.19    -> 1.22   
#	  include/linux/fi.h	1.5     -> 1.6    
#	drivers/char/fi/fi_mock_interceptor.c	1.2     -> 1.4    
#	               (new)	        -> 1.2
drivers/char/fi/fi_mock_cs.c
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/12/24	lo...@ha...	1.919
# * add code segment subsystem
# * add fi_mock_code_segment
# * clean some extern declarations in .c 
# --------------------------------------------
# 02/12/24	lo...@ha...	1.920
# add mock_code_segment file
# --------------------------------------------
# 02/12/24	lo...@ha...	1.921
# drivers/char/fi/fi_core.c
#     * fix a bug
#     * add code segment support
# drivers/char/fi/fi_mock_cs.c
#     reduce name length
# --------------------------------------------
# 02/12/24	lo...@ha...	1.922
# * refactor del_trigger (using find_trigger_by_name)
# * refactor fi_execute_trigger (breaking down small functions)
# --------------------------------------------
#
diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig
--- a/arch/i386/Kconfig	Tue Dec 24 16:57:18 2002
+++ b/arch/i386/Kconfig	Tue Dec 24 16:57:18 2002
@@ -1596,6 +1596,17 @@
 
           If in doubt say N.
 
+config FI_MOCK_CODE_SEGMENT
+	tristate "Fault Injection Mock Code Segment (EXPERIMENTAL)"
+	depends on FI
+	help
+	  This is a mock or fake code segment created for the sole purpose
of
+	  exercising the fault injection core code. The omly reason a person

+	  would want to build this component is to learn to write code
segment
+	  himself/herself.
+
+	  If in doubt say N
+
 config DEBUG_STACKOVERFLOW
 	bool "Check for stack overflows"
 	depends on DEBUG_KERNEL
diff -Nru a/drivers/char/fi/Makefile b/drivers/char/fi/Makefile
--- a/drivers/char/fi/Makefile	Tue Dec 24 16:57:18 2002
+++ b/drivers/char/fi/Makefile	Tue Dec 24 16:57:18 2002
@@ -9,5 +9,5 @@
 obj-$(CONFIG_FI) += fi_core.o
 obj-$(CONFIG_FI_TEST) += fi_test.o
 obj-$(CONFIG_FI_MOCK_INTERCEPTOR) += fi_mock_interceptor.o
-
+obj-$(CONFIG_FI_MOCK_CODE_SEGMENT) += fi_mock_cs.o
 export-objs	:= fi_core.o
diff -Nru a/drivers/char/fi/fi_core.c b/drivers/char/fi/fi_core.c
--- a/drivers/char/fi/fi_core.c	Tue Dec 24 16:57:18 2002
+++ b/drivers/char/fi/fi_core.c	Tue Dec 24 16:57:18 2002
@@ -67,6 +67,21 @@
 static struct trigger_attribute trigger_attr_count;
 static struct trigger_attribute trigger_attr_type;
 
+static inline struct trigger *find_trigger_by_name(const char *name)
+{
+	struct list_head * entry;
+	struct trigger * t;
+
+	list_for_each(entry,&trigger_subsys.list) {
+		t = to_trigger(entry);
+		if (!strncmp(t->kobj.name, name, KOBJ_NAME_LEN)) {
+			dbg("comparing %s to %s", t->kobj.name, name);
+			return t;
+		}
+	}
+	return NULL;
+}
+
 static inline void create_trigger_files(struct trigger *t)
 {
 	sysfs_create_file(&t->kobj, &trigger_attr_wp.attr);
@@ -163,24 +178,51 @@
 
 static inline ssize_t del_trigger(struct trigger *t)
 {
-	struct list_head * entry;
 	struct trigger * n;
 
-	list_for_each(entry,&trigger_subsys.list) {
-		n = to_trigger(entry);
-		if (!strncmp(n->kobj.name, t->kobj.name, KOBJ_NAME_LEN)) {
-			dbg("comparing %s to %s", n->kobj.name,
t->kobj.name);
-			unarm_trigger(n);
-			remove_trigger_files(n);
-			kobject_unregister(&n->kobj);
-			return 0;
-		}
+	n = find_trigger_by_name(t->kobj.name);
+	if (n) {
+		unarm_trigger(n);
+		remove_trigger_files(n);
+		kobject_unregister(&n->kobj);
+		return 0;
 	}
 
 	err("trigger %s does not exist", t->kobj.name);
 	return -EINVAL;
 }
 
+static struct code_segment_attribute code_segment_attr_trigger;
+
+static inline void create_code_segment_files(struct code_segment *cs)
+{
+	sysfs_create_file(&cs->kobj, &code_segment_attr_trigger.attr);
+}
+
+static inline void remove_code_segment_files(struct code_segment *cs)
+{
+	sysfs_remove_file(&cs->kobj, &code_segment_attr_trigger.attr);
+}
+
+static inline void arm_code_segment(struct code_segment *cs, struct trigger
*t) 
+{
+	kobject_get(&t->kobj);
+	kobject_get(&cs->kobj);
+	cs->tri = t;
+	t->cs = cs;
+}
+
+static inline void unarm_code_segment(struct code_segment *cs)
+{
+	struct trigger *t;
+	
+	t = cs->tri;
+	t->cs = NULL;
+	cs->tri = NULL;
+	kobject_put(&cs->kobj);
+	kobject_put(&t->kobj);
+}
+
 /*
  * ===========================================================
  *     <>-- Toplevel Containing Subsystem (fi_subsys) --<>
@@ -544,6 +586,125 @@
 	.parent         = &fi_subsys,
 };
 
+/*
+ * ===============================================================
+ * <>-- Code Segment Containing Subsystem (code_segment_subsys) --<>
+ * ---------------------------------------------------------------
+ */
+static ssize_t code_segment_attr_show(struct kobject * kobj, 
+				     struct attribute * attr,
+				     char * page, size_t count, 
+				     loff_t off)
+{
+	struct code_segment * cs = container_of(kobj,struct
code_segment,kobj);
+	struct code_segment_attribute * a = 
+		container_of(attr,struct code_segment_attribute,attr);
+
+	dbg("about to call show function for %s", a->attr.name);
+	return a->show ? a->show(cs,page,count,off) : 0;
+}
+
+static ssize_t code_segment_attr_store(struct kobject * kobj, 
+				      struct attribute * attr,
+				      const char * page, 
+				      size_t count, 
+				      loff_t off)
+{
+	struct code_segment * cs = container_of(kobj,struct
code_segment,kobj);
+	struct code_segment_attribute * a = 
+		container_of(attr,struct code_segment_attribute,attr);
+
+	dbg("about to call store function for %s", a->attr.name);
+	return a->store ? a->store(cs,page,count,off) : 0;
+};
+
+static struct sysfs_ops code_segment_sysfs_ops = {
+	.show	= code_segment_attr_show,
+	.store  = code_segment_attr_store,
+};
+
+static struct subsystem code_segment_subsys = {
+	.kobj	   = { .name = "code_segments" },
+	.sysfs_ops = &code_segment_sysfs_ops,
+	.parent    = &fi_subsys,	
+};
+
+static ssize_t code_segment_trigger_show(struct code_segment *cs,
+					char * page, size_t count,
+					loff_t off)
+{
+	if (off) return 0;
+	if (cs->tri) return snprintf(page,count,"%s\n",cs->tri->kobj.name);
+	return snprintf(page,count,"%s\n","(not attached yet)");
+}
+
+static ssize_t code_segment_trigger_store(struct code_segment *cs,
+					const char * page, size_t count,
+					loff_t off)
+{
+	struct trigger *t;
+	char tri_name[KOBJ_NAME_LEN];
+	sscanf(page, "%s", tri_name);
+	dbg("Try to find %s trigger", tri_name);
+	t = find_trigger_by_name(tri_name);
+	if(t) {
+		arm_code_segment(cs, t);
+	} else {
+		unarm_code_segment(cs);
+	}
+	return count;
+}
+
+static struct code_segment_attribute code_segment_attr_trigger = {
+	.attr = { .name = "trigger", .mode = 0644 },
+	.show = code_segment_trigger_show,
+	.store= code_segment_trigger_store
+};
+
+/*
+ * ===============================================================
+ * <>-- Others ;) --<>
+ * ---------------------------------------------------------------
+ */
+
+static inline int is_in_random(int hertz) 
+{
+	int tmp;
+	if (hertz==0 || hertz==1) return 1;
+	get_random_bytes(&tmp, sizeof(tmp));
+	return (tmp < 0xFFFFFFFF/hertz); 
+}
+
+static inline int is_in_range(int data, int min, int max, int bitmask)
+{
+	int tmp;
+	if (min==0 && max==0) return 1;
+	tmp = data & (~bitmask);
+	if ( min<=tmp && tmp<max) return 1;
+	return 0;
+}
+		
+static inline int is_ready(struct trigger *t, unsigned int val) 
+{	
+    	if ( is_in_random(t->hertz) 
+		&& is_in_range(val, t->min, t->max, t->bitmask)) {
+		return 1;
+	}
+	return 0;
+}
+
+static inline int is_in_count(int count, int skip, int stop) 
+{
+	if (skip >= count) return 0;
+	if (stop!=0 && (stop+skip) <count) return 0;
+	return 1;
+}
+
+static inline int protect_bits(int new, int orig, int bitmask) 
+{
+	return (new&(~bitmask)) | (orig&bitmask);
+}
+
 void fi_execute_trigger(struct trigger *t, struct interceptor *i,
 			__u32 val, int len, int type, void *data)
 {
@@ -551,38 +712,25 @@
 
 	if (!t) {
 		err("Unable to execute null trigger");
-		goto exit;
+		return;
 	}
 
-	get_random_bytes(&tmp, sizeof(tmp));
-	if (t->hertz==0) {t->hertz=1;};//divid is not 0!
-	if (tmp >= 0xFFFFFFFF/t->hertz){
-		dbg("rnd=%d, HERZ=%d", tmp, t->hertz);
-		goto exit;
-	}
-
-	tmp = val & (~t->bitmask);
-	if (t->min>tmp || tmp>=t->max){
-		dbg("min=%d, max=%d, val=%d", t->min, t->max, val);
-		if(!(t->min==0 && t->max==0))
-			goto exit;
-	}
+	if(!is_ready(t,val)) return;
 
 	/* increase count only when all conditions have passed */
 	atomic_inc(&t->count);
 
-	if (t->skip >= atomic_read(&t->count)){
-		dbg("count=%d, skip=%d", atomic_read(&t->count), t->skip);
-		goto exit;
-	}
-
-	if ( t->stop!=0 && (t->stop < (atomic_read(&t->count)-t->skip)) ) {
-		dbg("count=%d, stop=%d", atomic_read(&t->count), t->stop);
-		goto exit;
-	}
+	if(!is_in_count(atomic_read(&t->count), t->skip, t->stop)) return;
 
 	dbg("count=%d, skip=%d, min=%d, max=%d, val=%d",
 	    atomic_read(&t->count), t->skip, t->min, t->max, val);
+	
+	if (t->cs) {
+		t->cs->execute_trigger(t, i, val, len, type, data);
+		return;
+	}
+	
+	//legacy trigger logic code
 	tmp = val;
 	switch (t->opcode){
 	case TRIGGER_OPCODE_NOTHING:
@@ -620,9 +768,8 @@
 	}
 
  exit_for:
-	val = (val & (t->protection)) | (tmp & (~t->protection));
+	val = protect_bits(tmp, val, t->protection);
 
- exit:
 	i->corrupt(val, data);
 	return;	
 }
@@ -648,6 +795,27 @@
 	kobject_unregister(&i->kobj);
 }
 
+int fi_register_code_segment(struct code_segment *cs)
+{
+	if (!is_initialized)
+		fi_init();
+
+	dbg("registering code segment %s", cs->kobj.name);
+	cs->kobj.subsys = &code_segment_subsys;
+	if (kobject_register(&cs->kobj)) {
+		err("Unable to register kobject");
+		return -EINVAL;
+	}
+	create_code_segment_files(cs);
+	return 0;
+}
+
+void fi_unregister_code_segment(struct code_segment *cs)
+{
+	remove_code_segment_files(cs);
+	kobject_unregister(&cs->kobj);
+}
+
 static int __init fi_init(void)
 {
 	down(&fi_sem);
@@ -659,6 +827,7 @@
 	dbg("initializing fault injection core");
 	subsystem_register(&fi_subsys);
 	subsys_create_file(&fi_subsys,&fi_subsys_attr_debug);
+	subsystem_register(&code_segment_subsys);
 	subsystem_register(&interceptor_subsys);
 	subsystem_register(&trigger_subsys);
 	subsys_create_file(&trigger_subsys,&trigger_subsys_attr_ctl);
@@ -674,6 +843,7 @@
 	subsys_remove_file(&trigger_subsys,&trigger_subsys_attr_ctl);
 	subsystem_unregister(&trigger_subsys);
 	subsystem_unregister(&interceptor_subsys);
+	subsystem_register(&code_segment_subsys);
 	subsys_remove_file(&fi_subsys,&fi_subsys_attr_debug);
 	subsystem_unregister(&fi_subsys);
 }
@@ -684,6 +854,8 @@
 
 EXPORT_SYMBOL_GPL(fi_register_interceptor);
 EXPORT_SYMBOL_GPL(fi_unregister_interceptor);
+EXPORT_SYMBOL_GPL(fi_register_code_segment);
+EXPORT_SYMBOL_GPL(fi_unregister_code_segment);
 EXPORT_SYMBOL_GPL(fi_execute_trigger);
 EXPORT_SYMBOL_GPL(fi_debug);
 
diff -Nru a/drivers/char/fi/fi_mock_cs.c b/drivers/char/fi/fi_mock_cs.c
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/drivers/char/fi/fi_mock_cs.c	Tue Dec 24 16:57:18 2002
@@ -0,0 +1,42 @@
+/* Copyright (C) 2002 Louis Zhuang <lou...@in...> */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/kobject.h>
+#include <linux/fi.h>
+#include <linux/fi_internal.h>
+
+#define DRIVER_AUTHOR   "Louis Zhuang <lou...@in...>"
+#define DRIVER_DESC     "Fault Injection Mock Code Segment"
+
+void mock_execute(struct trigger *t, struct interceptor *i, 
+		__u32 val, int len, int type, void *data)
+{
+	info("tri=%s, intcpt=%s, val=%i, len=%i, type=%i, data=%p",
+			t->kobj.name, i->kobj.name, val, len, type,
+			data);
+}
+
+static struct code_segment mock_code_segment = {
+	.execute_trigger = mock_execute,
+	.kobj = {.name="mock"} 
+};
+
+static int __init mock_init(void)
+{
+	if (fi_register_code_segment(&mock_code_segment)) {
+		err("Failed to register Mock Code Segment\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void __exit mock_exit(void)
+{
+	fi_unregister_code_segment(&mock_code_segment);
+}
+module_init(mock_init);
+module_exit(mock_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff -Nru a/drivers/char/fi/fi_mock_interceptor.c
b/drivers/char/fi/fi_mock_interceptor.c
--- a/drivers/char/fi/fi_mock_interceptor.c	Tue Dec 24 16:57:18 2002
+++ b/drivers/char/fi/fi_mock_interceptor.c	Tue Dec 24 16:57:18 2002
@@ -44,10 +44,6 @@
 #define trace(format, arg...) \
                 printk(KERN_INFO "%s(" format ")\n", __FUNCTION__ , ## arg)
 
-extern int fi_register_interceptor(struct interceptor *);
-extern int fi_unregister_interceptor(struct interceptor *);
-extern void fi_execute_trigger(struct trigger*,struct interceptor*,
-			       __u32,int,int,void*);
 
 static struct interceptor mock_interceptor;
 
@@ -120,7 +116,7 @@
 
 	mock_interceptor.type = mock_type;
 	kobject_init(&mock_interceptor.kobj);
-	if (!fi_register_interceptor(&mock_interceptor)) {
+	if (fi_register_interceptor(&mock_interceptor)) {
 		dbg("Failed to register Mock Interceptor");
 
 		/* FIXME!! For some reason kobject_register */
diff -Nru a/drivers/char/fi/pf/pf.c b/drivers/char/fi/pf/pf.c
--- a/drivers/char/fi/pf/pf.c	Tue Dec 24 16:57:18 2002
+++ b/drivers/char/fi/pf/pf.c	Tue Dec 24 16:57:18 2002
@@ -269,8 +269,6 @@
 	.corrupt = &corrupt
 };
 
-extern int fi_register_interceptor(struct interceptor *);
-extern int fi_unregister_interceptor(struct interceptor *);
 static int __init pf_init(void) 
 {
 	return fi_register_interceptor(&pf_interceptor);
diff -Nru a/include/linux/fi.h b/include/linux/fi.h
--- a/include/linux/fi.h	Tue Dec 24 16:57:18 2002
+++ b/include/linux/fi.h	Tue Dec 24 16:57:18 2002
@@ -60,6 +60,19 @@
 	INTERCEPTOR_TYPE_PIO=2,
 } interceptor_type_t;
 
+struct trigger;
+struct interceptor;
+struct code_segment {
+	void (*execute_trigger) (struct trigger *t, 
+				 struct interceptor *i, 
+				 __u32 val, 
+				 int len, 
+				 int type, 
+				 void *data); 
+	struct trigger *tri;
+	struct kobject kobj;
+};
+
 struct trigger {
 	struct watchpoint wp;
 	__u32 bitmask;
@@ -71,6 +84,7 @@
 	int hertz;
 	int registered;
 	trigger_opcode_t opcode;
+	struct code_segment *cs;
 	int operand;
 	atomic_t count;
 	interceptor_type_t type;
@@ -88,10 +102,10 @@
 	struct kobject kobj;
 };
 
-struct interceptor_attribute {
+struct code_segment_attribute {
 	struct attribute attr;
-	ssize_t (*show) (struct interceptor *,char *,size_t,loff_t);
-	ssize_t (*store)(struct interceptor *,const char *,size_t, loff_t);
+	ssize_t (*show) (struct code_segment *,char *,size_t,loff_t);
+	ssize_t (*store) (struct code_segment *,const char *,size_t,loff_t);
 };
 
 struct trigger_attribute {
@@ -99,6 +113,20 @@
 	ssize_t (*show) (struct trigger *,char *,size_t,loff_t);
 	ssize_t (*store)(struct trigger *,const char *,size_t,loff_t);
 };
+
+struct interceptor_attribute {
+	struct attribute attr;
+	ssize_t (*show) (struct interceptor *,char *,size_t,loff_t);
+	ssize_t (*store)(struct interceptor *,const char *,size_t, loff_t);
+};
+
+
+extern int fi_register_interceptor(struct interceptor *);
+extern void fi_unregister_interceptor(struct interceptor *i);
+extern int fi_register_code_segment(struct code_segment *);
+extern void fi_unregister_code_segment(struct code_segment *);
+extern void fi_execute_trigger(struct trigger *t, struct interceptor *i,
+				__u32 val, int len, int type, void *data);
 
 #endif	/* __KERNEL__ */
 #endif	/* _FAULT_INJECTION_H */