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-rw-r--r--tapset/kretprobe.stp56
1 files changed, 56 insertions, 0 deletions
diff --git a/tapset/kretprobe.stp b/tapset/kretprobe.stp
new file mode 100644
index 00000000..3742708f
--- /dev/null
+++ b/tapset/kretprobe.stp
@@ -0,0 +1,56 @@
+// kretprobe data tapset
+// Copyright (C) 2009 Red Hat Inc.
+//
+// This file is part of systemtap, and is free software. You can
+// redistribute it and/or modify it under the terms of the GNU General
+// Public License (GPL); either version 2, or (at your option) any
+// later version.
+
+
+// This is an internally-used tapset for sharing data between kretprobe
+// entry / return handlers. See the function
+// dwarf_var_expanding_visitor::gen_kretprobe_saved_return
+// for details.
+//
+// Note, invalid calls are silently ignored...
+
+%{
+static void *
+_kretprobe_data(struct kretprobe_instance *pi, size_t offset, size_t length)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
+ size_t end = offset + length;
+ if (end > offset && pi && end <= pi->rp->data_size)
+ return &pi->data[offset];
+#endif
+ return NULL;
+}
+%}
+
+function _get_kretprobe_long:long(i:long) %{ /* pure */
+ size_t offset = THIS->i * sizeof(int64_t);
+ const int64_t *data = _kretprobe_data(CONTEXT->pi, offset, sizeof(int64_t));
+ THIS->__retvalue = data ? *data : 0;
+%}
+
+function _set_kretprobe_long(i:long, value:long) %{ /* impure */
+ size_t offset = THIS->i * sizeof(int64_t);
+ int64_t *data = _kretprobe_data(CONTEXT->pi, offset, sizeof(int64_t));
+ if (data)
+ *data = THIS->value;
+%}
+
+function _get_kretprobe_string:string(i:long) %{ /* pure */
+ size_t offset = CONTEXT->pi_longs * sizeof(int64_t) +
+ THIS->i * MAXSTRINGLEN;
+ const char *data = _kretprobe_data(CONTEXT->pi, offset, MAXSTRINGLEN);
+ strlcpy(THIS->__retvalue, data ?: "", MAXSTRINGLEN);
+%}
+
+function _set_kretprobe_string(i:long, value:string) %{ /* impure */
+ size_t offset = CONTEXT->pi_longs * sizeof(int64_t) +
+ THIS->i * MAXSTRINGLEN;
+ char *data = _kretprobe_data(CONTEXT->pi, offset, MAXSTRINGLEN);
+ if (data)
+ strlcpy(data, THIS->value, MAXSTRINGLEN);
+%}