Document last supported kernel version for stable-2.11 branch

[lttng-modules.git] / lttng-filter-interpreter.c

diff --git a/lttng-filter-interpreter.c b/lttng-filter-interpreter.c
index 21169f01fe3ef22fc0f996246d898564366676b8..6e5a5139e3dfd285fe0500c2558b8c1982fb49ba 100644 (file)
--- a/lttng-filter-interpreter.c
+++ b/lttng-filter-interpreter.c
@@ -8,7 +8,7 @@
  */
 
 #include <wrapper/uaccess.h>
-#include <wrapper/frame.h>
+#include <wrapper/objtool.h>
 #include <wrapper/types.h>
 #include <linux/swab.h>
 
@@ -22,7 +22,7 @@ LTTNG_STACK_FRAME_NON_STANDARD(lttng_filter_interpret_bytecode);
  * to handle user-space read.
  */
 static
-char get_char(struct estack_entry *reg, size_t offset)
+char get_char(const struct estack_entry *reg, size_t offset)
 {
        if (unlikely(offset >= reg->u.s.seq_len))
                return '\0';
@@ -593,6 +593,39 @@ end:
        return ret;
 }
 
+#ifdef DEBUG
+
+#define DBG_USER_STR_CUTOFF 32
+
+/*
+ * In debug mode, print user string (truncated, if necessary).
+ */
+static inline
+void dbg_load_ref_user_str_printk(const struct estack_entry *user_str_reg)
+{
+       size_t pos = 0;
+       char last_char;
+       char user_str[DBG_USER_STR_CUTOFF];
+
+       pagefault_disable();
+       do {
+               last_char = get_char(user_str_reg, pos);
+               user_str[pos] = last_char;
+               pos++;
+       } while (last_char != '\0' && pos < sizeof(user_str));
+       pagefault_enable();
+
+       user_str[sizeof(user_str) - 1] = '\0';
+       dbg_printk("load field ref user string: '%s%s'\n", user_str,
+               last_char != '\0' ? "[...]" : "");
+}
+#else
+static inline
+void dbg_load_ref_user_str_printk(const struct estack_entry *user_str_reg)
+{
+}
+#endif
+
 /*
  * Return 0 (discard), or raise the 0x1 flag (log event).
  * Currently, other flags are kept for future extensions and have no
@@ -1313,7 +1346,7 @@ uint64_t lttng_filter_interpret_bytecode(void *filter_data,
                        estack_push(stack, top, ax, bx);
                        estack_ax(stack, top)->u.s.user_str =
                                *(const char * const *) &filter_stack_data[ref->offset];
-                       if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+                       if (unlikely(!estack_ax(stack, top)->u.s.user_str)) {
                                dbg_printk("Filter warning: loading a NULL string.\n");
                                ret = -EINVAL;
                                goto end;
@@ -1322,7 +1355,7 @@ uint64_t lttng_filter_interpret_bytecode(void *filter_data,
                        estack_ax(stack, top)->u.s.literal_type =
                                ESTACK_STRING_LITERAL_TYPE_NONE;
                        estack_ax(stack, top)->u.s.user = 1;
-                       dbg_printk("ref load string %s\n", estack_ax(stack, top)->u.s.str);
+                       dbg_load_ref_user_str_printk(estack_ax(stack, top));
                        next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
                        PO;
                }
@@ -1340,7 +1373,7 @@ uint64_t lttng_filter_interpret_bytecode(void *filter_data,
                        estack_ax(stack, top)->u.s.user_str =
                                *(const char **) (&filter_stack_data[ref->offset
                                                                + sizeof(unsigned long)]);
-                       if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+                       if (unlikely(!estack_ax(stack, top)->u.s.user_str)) {
                                dbg_printk("Filter warning: loading a NULL sequence.\n");
                                ret = -EINVAL;
                                goto end;