perf probe: Add data structure member access support
Support accessing members in the data structures. With this,
perf-probe accepts data-structure members(IOW, it now accepts
dot '.' and arrow '->' operators) as probe arguemnts.
e.g.
./perf probe --add 'schedule:44 rq->curr'
./perf probe --add 'vfs_read file->f_op->read file->f_path.dentry'
Note that '>' can be interpreted as redirection in command-line.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220626.32050.57552.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4e3c1ae..64dea6c 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -262,6 +262,49 @@
pp->lazy_line);
}
+/* Parse perf-probe event argument */
+static void parse_perf_probe_arg(const char *str, struct perf_probe_arg *arg)
+{
+ const char *tmp;
+ struct perf_probe_arg_field **fieldp;
+
+ pr_debug("parsing arg: %s into ", str);
+
+ tmp = strpbrk(str, "-.");
+ if (!is_c_varname(str) || !tmp) {
+ /* A variable, register, symbol or special value */
+ arg->name = xstrdup(str);
+ pr_debug("%s\n", arg->name);
+ return;
+ }
+
+ /* Structure fields */
+ arg->name = xstrndup(str, tmp - str);
+ pr_debug("%s, ", arg->name);
+ fieldp = &arg->field;
+
+ do {
+ *fieldp = xzalloc(sizeof(struct perf_probe_arg_field));
+ if (*tmp == '.') {
+ str = tmp + 1;
+ (*fieldp)->ref = false;
+ } else if (tmp[1] == '>') {
+ str = tmp + 2;
+ (*fieldp)->ref = true;
+ } else
+ semantic_error("Argument parse error: %s", str);
+
+ tmp = strpbrk(str, "-.");
+ if (tmp) {
+ (*fieldp)->name = xstrndup(str, tmp - str);
+ pr_debug("%s(%d), ", (*fieldp)->name, (*fieldp)->ref);
+ fieldp = &(*fieldp)->next;
+ }
+ } while (tmp);
+ (*fieldp)->name = xstrdup(str);
+ pr_debug("%s(%d)\n", (*fieldp)->name, (*fieldp)->ref);
+}
+
/* Parse perf-probe event command */
void parse_perf_probe_command(const char *cmd, struct perf_probe_event *pev)
{
@@ -281,7 +324,7 @@
pev->nargs = argc - 1;
pev->args = xzalloc(sizeof(struct perf_probe_arg) * pev->nargs);
for (i = 0; i < pev->nargs; i++) {
- pev->args[i].name = xstrdup(argv[i + 1]);
+ parse_perf_probe_arg(argv[i + 1], &pev->args[i]);
if (is_c_varname(pev->args[i].name) && pev->point.retprobe)
semantic_error("You can't specify local variable for"
" kretprobe");
@@ -353,6 +396,33 @@
argv_free(argv);
}
+/* Compose only probe arg */
+int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf, size_t len)
+{
+ struct perf_probe_arg_field *field = pa->field;
+ int ret;
+ char *tmp = buf;
+
+ ret = e_snprintf(tmp, len, "%s", pa->name);
+ if (ret <= 0)
+ goto error;
+ tmp += ret;
+ len -= ret;
+
+ while (field) {
+ ret = e_snprintf(tmp, len, "%s%s", field->ref ? "->" : ".",
+ field->name);
+ if (ret <= 0)
+ goto error;
+ tmp += ret;
+ len -= ret;
+ field = field->next;
+ }
+ return tmp - buf;
+error:
+ die("Failed to synthesize perf probe argument: %s", strerror(-ret));
+}
+
/* Compose only probe point (not argument) */
static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
{
@@ -563,6 +633,7 @@
void clear_perf_probe_event(struct perf_probe_event *pev)
{
struct perf_probe_point *pp = &pev->point;
+ struct perf_probe_arg_field *field, *next;
int i;
if (pev->event)
@@ -575,9 +646,18 @@
free(pp->function);
if (pp->lazy_line)
free(pp->lazy_line);
- for (i = 0; i < pev->nargs; i++)
+ for (i = 0; i < pev->nargs; i++) {
if (pev->args[i].name)
free(pev->args[i].name);
+ field = pev->args[i].field;
+ while (field) {
+ next = field->next;
+ if (field->name)
+ free(field->name);
+ free(field);
+ field = next;
+ }
+ }
if (pev->args)
free(pev->args);
memset(pev, 0, sizeof(*pev));
@@ -682,8 +762,10 @@
if (pev->nargs > 0) {
printf(" with");
- for (i = 0; i < pev->nargs; i++)
- printf(" %s", pev->args[i].name);
+ for (i = 0; i < pev->nargs; i++) {
+ synthesize_perf_probe_arg(&pev->args[i], buf, 128);
+ printf(" %s", buf);
+ }
}
printf(")\n");
free(place);