perf probe: Support "string" type
Support string type casting to event argument. If perf-probe finds an argument
casted as string, it ensures the target variable is "(unsigned/signed) char
*(or []). perf-probe also adds dereference if the target is a pointer.
So, both of 'char buf[10];' and 'char *buf;' can be accessed by 'buf:string'
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100519195734.2885.1666.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index baf6653..aaea16b 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -464,18 +464,61 @@
}
static int convert_variable_type(Dwarf_Die *vr_die,
- struct kprobe_trace_arg *targ)
+ struct kprobe_trace_arg *tvar,
+ const char *cast)
{
+ struct kprobe_trace_arg_ref **ref_ptr = &tvar->ref;
Dwarf_Die type;
char buf[16];
int ret;
+ /* TODO: check all types */
+ if (cast && strcmp(cast, "string") != 0) {
+ /* Non string type is OK */
+ tvar->type = strdup(cast);
+ return (tvar->type == NULL) ? -ENOMEM : 0;
+ }
+
if (die_get_real_type(vr_die, &type) == NULL) {
pr_warning("Failed to get a type information of %s.\n",
dwarf_diename(vr_die));
return -ENOENT;
}
+ if (cast && strcmp(cast, "string") == 0) { /* String type */
+ ret = dwarf_tag(&type);
+ if (ret != DW_TAG_pointer_type &&
+ ret != DW_TAG_array_type) {
+ pr_warning("Failed to cast into string: "
+ "%s(%s) is not a pointer nor array.",
+ dwarf_diename(vr_die), dwarf_diename(&type));
+ return -EINVAL;
+ }
+ if (ret == DW_TAG_pointer_type) {
+ if (die_get_real_type(&type, &type) == NULL) {
+ pr_warning("Failed to get a type information.");
+ return -ENOENT;
+ }
+ while (*ref_ptr)
+ ref_ptr = &(*ref_ptr)->next;
+ /* Add new reference with offset +0 */
+ *ref_ptr = zalloc(sizeof(struct kprobe_trace_arg_ref));
+ if (*ref_ptr == NULL) {
+ pr_warning("Out of memory error\n");
+ return -ENOMEM;
+ }
+ }
+ if (die_compare_name(&type, "char") != 0 &&
+ die_compare_name(&type, "unsigned char") != 0) {
+ pr_warning("Failed to cast into string: "
+ "%s is not (unsigned) char *.",
+ dwarf_diename(vr_die));
+ return -EINVAL;
+ }
+ tvar->type = strdup(cast);
+ return (tvar->type == NULL) ? -ENOMEM : 0;
+ }
+
ret = die_get_byte_size(&type) * 8;
if (ret) {
/* Check the bitwidth */
@@ -495,8 +538,8 @@
strerror(-ret));
return ret;
}
- targ->type = strdup(buf);
- if (targ->type == NULL)
+ tvar->type = strdup(buf);
+ if (tvar->type == NULL)
return -ENOMEM;
}
return 0;
@@ -606,14 +649,8 @@
&die_mem);
vr_die = &die_mem;
}
- if (ret == 0) {
- if (pf->pvar->type) {
- pf->tvar->type = strdup(pf->pvar->type);
- if (pf->tvar->type == NULL)
- ret = -ENOMEM;
- } else
- ret = convert_variable_type(vr_die, pf->tvar);
- }
+ if (ret == 0)
+ ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
/* *expr will be cached in libdw. Don't free it. */
return ret;
error: