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perf probe: Add data structure member access support

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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>
This commit is contained in:
Masami Hiramatsu 2010-03-16 18:06:26 -04:00 • committed by Ingo Molnar
parent fb1587d869
commit 7df2f32956
3 changed files with 201 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

90
tools/perf/util/probe-event.c
View file

@ -262,6 +262,49 @@ static void parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
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 @@ void parse_perf_probe_command(const char *cmd, struct perf_probe_event *pev)
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 @@ void parse_kprobe_trace_command(const char *cmd, struct kprobe_trace_event *tev)
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 convert_to_perf_probe_event(struct kprobe_trace_event *tev,
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 @@ void clear_perf_probe_event(struct perf_probe_event *pev)
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 @@ static void show_perf_probe_event(struct perf_probe_event *pev)
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);