FIXME: handling trace_seq and seq_buffer changes

check struct defintion rather than KERNLE_VERSION_CODE to
handle structure changes in kernel v6.8/v3.19/v2.6.33/...

Signed-off-by: shenping.matt <shenping.matt@bytedance.com>

Author: shenping-bd

driver/LKM/Makefile

@@ -10,6 +10,10 @@ obj-m			+= $(MODULE_NAME).o
 ccflags-y		+= -I$(MODULE_DIR)/include -I$(MODULE_DIR)
 
 K_I_PATH		:= .
+ifneq ($(wildcard $(srctree)/include/.),)
+K_I_PATH                += $(srctree)/include
+endif
+
 ifneq ($(wildcard /usr/src/kernels/$(KERNEL_HEAD)/include/.),)
 K_I_PATH		+= /usr/src/kernels/$(KERNEL_HEAD)/include
 endif
@@ -67,10 +71,22 @@ ccflags-y += -D SMITH_TRACE_EVENTS
 endif
 
 TRACE_SEQ_FILES := $(shell find -L $(K_I_PATH) -path \*/linux/trace_seq.h) /dev/null
-TRACE_SEQ_SEQ := $(shell sh -c "grep -s trace_seq_used $(TRACE_SEQ_FILES)")
+TRACE_SEQ_SEQ := $(shell sh -c "grep -s 'struct trace_seq {' -A5 $(TRACE_SEQ_FILES) | grep 'seq;'")
 ifneq ($(TRACE_SEQ_SEQ),)
 ccflags-y += -D SMITH_TRACE_SEQ
 endif
+TRACE_SEQ_READPOS := $(shell sh -c "grep -s 'struct trace_seq {' -A5 $(TRACE_SEQ_FILES) | grep 'readpos;'")
+ifneq ($(TRACE_SEQ_READPOS),)
+ccflags-y += -D SMITH_TRACE_READPOS
+endif
+TRACE_SEQ_FULL := $(shell sh -c "grep -s 'struct trace_seq {' -A5 $(TRACE_SEQ_FILES) | grep 'full;'")
+ifneq ($(TRACE_SEQ_FULL),)
+ccflags-y += -D SMITH_TRACE_FULL
+endif
+TRACE_SEQ_LEN := $(shell sh -c "grep -s 'struct trace_seq {' -A5 $(TRACE_SEQ_FILES) | grep 'len;'")
+ifneq ($(TRACE_SEQ_LEN),)
+ccflags-y += -D SMITH_TRACE_LEN
+endif
 
 FS_H_FILES := $(shell find -L $(K_I_PATH) -path "*/linux/fs.h") /dev/null
 FS_OP_ITERATE := $(shell sh -c "grep -s \(\*iterate\) $(FS_H_FILES)")
@@ -117,7 +133,15 @@ endif
 else
 
 MODULE_DIR		:= $(shell pwd)
-KERNEL_DIR		:= $(if $(wildcard /usr/src/kernels/$(KERNEL_HEAD)),/usr/src/kernels/$(KERNEL_HEAD),/lib/modules/$(KERNEL_HEAD)/build)
+ifneq ($(wildcard /lib/modules/$(KERNEL_HEAD)/build),)
+KERNEL_DIR		:= /lib/modules/$(KERNEL_HEAD)/build
+else ifneq ($(wildcard /usr/src/kernels/$(KERNEL_HEAD)),)
+KERNEL_DIR		:= /usr/src/kernels/$(KERNEL_HEAD)
+else ifneq ($(wildcard /usr/src/$(KERNEL_HEAD)),)
+KERNEL_DIR		:= /usr/src/$(KERNEL_HEAD)
+else
+$(error Kernel header files related to $(KERNEL_HEAD) not found)
+endif
 
 all:
 	@echo "|-----------------------------------|"

driver/LKM/include/trace.h

@@ -23,7 +23,7 @@
 #define SZ_128K				0x00020000
 
 
-#ifdef SMITH_TRACE_SEQ
+#ifdef SMITH_TRACE_SEQ /* from kernel v3.19 */
 static inline int __trace_seq_used(struct trace_seq *s)
 {
 	return trace_seq_used(s);
@@ -48,15 +48,16 @@ static inline int __trace_seq_used(struct trace_seq *s)
 {
     return min(s->len, (unsigned int)(PAGE_SIZE - 1));
 }
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 5, 0)
+
+#ifdef SMITH_TRACE_FULL /* fromm 2.6.33 */
 static inline bool __trace_seq_has_overflowed(struct trace_seq *s)
 {
-    return s->len > PAGE_SIZE - 1;
+    return s->full || s->len > PAGE_SIZE - 1;
 }
 #else
 static inline bool __trace_seq_has_overflowed(struct trace_seq *s)
 {
-    return s->full || s->len > PAGE_SIZE - 1;
+    return s->len > PAGE_SIZE - 1;
 }
 #endif
 
@@ -70,7 +71,7 @@ static inline enum print_line_t __trace_handle_return(struct trace_seq *s)
     return __trace_seq_has_overflowed(s) ?
            TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
 }
-#endif
+#endif /* SMITH_TRACE_SEQ */
 
 /*
  * The print entry - the most basic unit of tracing.

driver/LKM/src/trace.c

@@ -41,7 +41,7 @@ static ssize_t(*trace_seq_to_user_sym) (struct trace_seq * s,
 #define trace_seq_to_user_sym trace_seq_to_user
 #endif
 
-static int kallsyms_lookup_symbols(void)
+static int trace_lookup_symbols(void)
 {
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
     void *ptr = (void *)smith_kallsyms_lookup_name("trace_seq_to_user");
@@ -278,18 +278,18 @@ static ssize_t trace_read_pipe(struct file *filp, char __user * ubuf,
     mutex_lock(&access_lock);
     while (trace_next_entry_inc(iter) != NULL) {
         enum print_line_t ret;
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
-        int save_len = iter->seq.seq.len;
-#else
+#ifdef SMITH_TRACE_LEN
         int save_len = iter->seq.len;
+#else
+        int save_len = iter->seq.seq.len;
 #endif
         ret = print_trace_fmt_line(iter);
         if (ret == TRACE_TYPE_PARTIAL_LINE) {
             /* don't print partial lines */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
-            iter->seq.seq.len = save_len;
-#else
+#ifdef SMITH_TRACE_LEN
             iter->seq.len = save_len;
+#else
+            iter->seq.seq.len = save_len;
 #endif
             break;
         }
@@ -304,18 +304,18 @@ static ssize_t trace_read_pipe(struct file *filp, char __user * ubuf,
     * size and we should leave by partial output condition above.
     * One of the trace_seq_* functions is not used properly.
     */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0)
+#ifdef SMITH_TRACE_FULL
         WARN_ONCE(iter->seq.full, "full flag set for trace id: %d", iter->ent->id);
 #endif
     }
     mutex_unlock(&access_lock);
 
 /* Now copy what we have to the user */
     sret = trace_seq_to_user_sym(&iter->seq, ubuf, cnt);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 19, 0)
-    if (iter->seq.seq.readpos >= __trace_seq_used(&iter->seq))
-#else
+#ifdef SMITH_TRACE_READPOS
     if (iter->seq.readpos >= __trace_seq_used(&iter->seq))
+#else
+    if (iter->seq.seq.readpos >= __trace_seq_used(&iter->seq))
 #endif
     trace_seq_init(&iter->seq);
 
@@ -399,7 +399,7 @@ static int __init print_event_init(void)
     if (num_class >= PRINT_EVENT_ID_MAX)
         return -EINVAL;
 
-    if (kallsyms_lookup_symbols())
+    if (trace_lookup_symbols())
         return -ENODEV;
 
     trace_ring = tb_alloc(RB_BUFFER_SIZE, TB_FL_OVERWRITE);