[tip:perf/core] perf probe: Use strbuf for making strings

tip-bot for Masami Hiramatsu
2016-05-01T07:39:31Z

Commit-ID: 909b0360ae358f212f526e171ea4ef433b1b4103
Gitweb: http://git.kernel.org/tip/909b0360ae358f212f526e171ea4ef433b1b4103
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 28 Apr 2016 03:37:14 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 28 Apr 2016 09:58:58 -0300

perf probe: Use strbuf for making strings

Replace many fixed-length char array with strbuf to stringify
perf_probe_event and probe_trace_event etc.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160427183713.23446.97377.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/probe-event.c | 246 ++++++++++++++---------------------------
tools/perf/util/probe-event.h | 2 +-
tools/perf/util/probe-finder.c | 14 +--
3 files changed, 93 insertions(+), 169 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a977462..85d82f4 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1673,69 +1673,51 @@ out:
}

/* Compose only probe arg */
-int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf, size_t len)
+char *synthesize_perf_probe_arg(struct perf_probe_arg *pa)
{
struct perf_probe_arg_field *field = pa->field;
- int ret;
- char *tmp = buf;
+ struct strbuf buf;
+ char *ret;

+ strbuf_init(&buf, 64);
if (pa->name && pa->var)
- ret = e_snprintf(tmp, len, "%s=%s", pa->name, pa->var);
+ strbuf_addf(&buf, "%s=%s", pa->name, pa->var);
else
- ret = e_snprintf(tmp, len, "%s", pa->name ? pa->name : pa->var);
- if (ret <= 0)
- goto error;
- tmp += ret;
- len -= ret;
+ strbuf_addstr(&buf, pa->name ?: pa->var);

while (field) {
if (field->name[0] == '[')
- ret = e_snprintf(tmp, len, "%s", field->name);
+ strbuf_addstr(&buf, field->name);
else
- ret = e_snprintf(tmp, len, "%s%s",
- field->ref ? "->" : ".", field->name);
- if (ret <= 0)
- goto error;
- tmp += ret;
- len -= ret;
+ strbuf_addf(&buf, "%s%s", field->ref ? "->" : ".",
+ field->name);
field = field->next;
}

- if (pa->type) {
- ret = e_snprintf(tmp, len, ":%s", pa->type);
- if (ret <= 0)
- goto error;
- tmp += ret;
- len -= ret;
- }
+ if (pa->type)
+ strbuf_addf(&buf, ":%s", pa->type);
+
+ ret = strbuf_detach(&buf, NULL);

- return tmp - buf;
-error:
- pr_debug("Failed to synthesize perf probe argument: %d\n", ret);
return ret;
}

/* Compose only probe point (not argument) */
static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
{
- char *buf, *tmp;
- char offs[32] = "", line[32] = "", file[32] = "";
- int ret, len;
-
- buf = zalloc(MAX_CMDLEN);
- if (buf == NULL) {
- ret = -ENOMEM;
- goto error;
- }
- if (pp->offset) {
- ret = e_snprintf(offs, 32, "+%lu", pp->offset);
- if (ret <= 0)
- goto error;
- }
- if (pp->line) {
- ret = e_snprintf(line, 32, ":%d", pp->line);
- if (ret <= 0)
- goto error;
+ struct strbuf buf;
+ char *tmp;
+ int len;
+
+ strbuf_init(&buf, 64);
+ if (pp->function) {
+ strbuf_addstr(&buf, pp->function);
+ if (pp->offset)
+ strbuf_addf(&buf, "+%lu", pp->offset);
+ else if (pp->line)
+ strbuf_addf(&buf, ":%d", pp->line);
+ else if (pp->retprobe)
+ strbuf_addstr(&buf, "%return");
}
if (pp->file) {
tmp = pp->file;
@@ -1744,25 +1726,12 @@ static char *synthesize_perf_probe_point(struct perf_probe_point *pp)
tmp = strchr(pp->file + len - 30, '/');
tmp = tmp ? tmp + 1 : pp->file + len - 30;
}
- ret = e_snprintf(file, 32, "@%s", tmp);
- if (ret <= 0)
- goto error;
+ strbuf_addf(&buf, "@%s", tmp);
+ if (!pp->function && pp->line)
+ strbuf_addf(&buf, ":%d", pp->line);
}

- if (pp->function)
- ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s%s", pp->function,
- offs, pp->retprobe ? "%return" : "", line,
- file);
- else
- ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", file, line);
- if (ret <= 0)
- goto error;
-
- return buf;
-error:
- pr_debug("Failed to synthesize perf probe point: %d\n", ret);
- free(buf);
- return NULL;
+ return strbuf_detach(&buf, NULL);
}

#if 0
@@ -1791,45 +1760,30 @@ char *synthesize_perf_probe_command(struct perf_probe_event *pev)
#endif

static int __synthesize_probe_trace_arg_ref(struct probe_trace_arg_ref *ref,
- char **buf, size_t *buflen,
- int depth)
+ struct strbuf *buf, int depth)
{
- int ret;
if (ref->next) {
depth = __synthesize_probe_trace_arg_ref(ref->next, buf,
- buflen, depth + 1);
+ depth + 1);
if (depth < 0)
goto out;
}
-
- ret = e_snprintf(*buf, *buflen, "%+ld(", ref->offset);
- if (ret < 0)
- depth = ret;
- else {
- *buf += ret;
- *buflen -= ret;
- }
+ strbuf_addf(buf, "%+ld(", ref->offset);
out:
return depth;
-
}

static int synthesize_probe_trace_arg(struct probe_trace_arg *arg,
- char *buf, size_t buflen)
+ struct strbuf *buf)
{
struct probe_trace_arg_ref *ref = arg->ref;
- int ret, depth = 0;
- char *tmp = buf;
+ int depth = 0;

/* Argument name or separator */
if (arg->name)
- ret = e_snprintf(buf, buflen, " %s=", arg->name);
+ strbuf_addf(buf, " %s=", arg->name);
else
- ret = e_snprintf(buf, buflen, " ");
- if (ret < 0)
- return ret;
- buf += ret;
- buflen -= ret;
+ strbuf_addch(buf, ' ');

/* Special case: @XXX */
if (arg->value[0] == '@' && arg->ref)
@@ -1837,60 +1791,41 @@ static int synthesize_probe_trace_arg(struct probe_trace_arg *arg,

/* Dereferencing arguments */
if (ref) {
- depth = __synthesize_probe_trace_arg_ref(ref, &buf,
- &buflen, 1);
+ depth = __synthesize_probe_trace_arg_ref(ref, buf, 1);
if (depth < 0)
return depth;
}

/* Print argument value */
if (arg->value[0] == '@' && arg->ref)
- ret = e_snprintf(buf, buflen, "%s%+ld", arg->value,
- arg->ref->offset);
+ strbuf_addf(buf, "%s%+ld", arg->value, arg->ref->offset);
else
- ret = e_snprintf(buf, buflen, "%s", arg->value);
- if (ret < 0)
- return ret;
- buf += ret;
- buflen -= ret;
+ strbuf_addstr(buf, arg->value);

/* Closing */
- while (depth--) {
- ret = e_snprintf(buf, buflen, ")");
- if (ret < 0)
- return ret;
- buf += ret;
- buflen -= ret;
- }
+ while (depth--)
+ strbuf_addch(buf, ')');
/* Print argument type */
- if (arg->type) {
- ret = e_snprintf(buf, buflen, ":%s", arg->type);
- if (ret <= 0)
- return ret;
- buf += ret;
- }
+ if (arg->type)
+ strbuf_addf(buf, ":%s", arg->type);

- return buf - tmp;
+ return 0;
}

char *synthesize_probe_trace_command(struct probe_trace_event *tev)
{
struct probe_trace_point *tp = &tev->point;
- char *buf;
- int i, len, ret;
-
- buf = zalloc(MAX_CMDLEN);
- if (buf == NULL)
- return NULL;
-
- len = e_snprintf(buf, MAX_CMDLEN, "%c:%s/%s ", tp->retprobe ? 'r' : 'p',
- tev->group, tev->event);
- if (len <= 0)
- goto error;
+ struct strbuf buf;
+ char *ret = NULL;
+ int i;

/* Uprobes must have tp->module */
if (tev->uprobes && !tp->module)
- goto error;
+ return NULL;
+
+ strbuf_init(&buf, 32);
+ strbuf_addf(&buf, "%c:%s/%s ", tp->retprobe ? 'r' : 'p',
+ tev->group, tev->event);
/*
* If tp->address == 0, then this point must be a
* absolute address uprobe.
@@ -1904,34 +1839,23 @@ char *synthesize_probe_trace_command(struct probe_trace_event *tev)

/* Use the tp->address for uprobes */
if (tev->uprobes)
- ret = e_snprintf(buf + len, MAX_CMDLEN - len, "%s:0x%lx",
- tp->module, tp->address);
+ strbuf_addf(&buf, "%s:0x%lx", tp->module, tp->address);
else if (!strncmp(tp->symbol, "0x", 2))
/* Absolute address. See try_to_find_absolute_address() */
- ret = e_snprintf(buf + len, MAX_CMDLEN - len, "%s%s0x%lx",
- tp->module ?: "", tp->module ? ":" : "",
- tp->address);
+ strbuf_addf(&buf, "%s%s0x%lx", tp->module ?: "",
+ tp->module ? ":" : "", tp->address);
else
- ret = e_snprintf(buf + len, MAX_CMDLEN - len, "%s%s%s+%lu",
- tp->module ?: "", tp->module ? ":" : "",
- tp->symbol, tp->offset);
-
- if (ret <= 0)
- goto error;
- len += ret;
+ strbuf_addf(&buf, "%s%s%s+%lu", tp->module ?: "",
+ tp->module ? ":" : "", tp->symbol, tp->offset);

- for (i = 0; i < tev->nargs; i++) {
- ret = synthesize_probe_trace_arg(&tev->args[i], buf + len,
- MAX_CMDLEN - len);
- if (ret <= 0)
+ for (i = 0; i < tev->nargs; i++)
+ if (synthesize_probe_trace_arg(&tev->args[i], &buf) < 0)
goto error;
- len += ret;
- }

- return buf;
+ ret = strbuf_detach(&buf, NULL);
error:
- free(buf);
- return NULL;
+ strbuf_release(&buf);
+ return ret;
}

static int find_perf_probe_point_from_map(struct probe_trace_point *tp,
@@ -2013,7 +1937,7 @@ static int convert_to_perf_probe_point(struct probe_trace_point *tp,
static int convert_to_perf_probe_event(struct probe_trace_event *tev,
struct perf_probe_event *pev, bool is_kprobe)
{
- char buf[64] = "";
+ struct strbuf buf = STRBUF_INIT;
int i, ret;

/* Convert event/group name */
@@ -2036,9 +1960,9 @@ static int convert_to_perf_probe_event(struct probe_trace_event *tev,
if (tev->args[i].name)
pev->args[i].name = strdup(tev->args[i].name);
else {
- ret = synthesize_probe_trace_arg(&tev->args[i],
- buf, 64);
- pev->args[i].name = strdup(buf);
+ strbuf_init(&buf, 32);
+ ret = synthesize_probe_trace_arg(&tev->args[i], &buf);
+ pev->args[i].name = strbuf_detach(&buf, NULL);
}
if (pev->args[i].name == NULL && ret >= 0)
ret = -ENOMEM;
@@ -2216,37 +2140,37 @@ static int perf_probe_event__sprintf(const char *group, const char *event,
const char *module,
struct strbuf *result)
{
- int i, ret;
- char buf[128];
- char *place;
+ int i;
+ char *buf;

- /* Synthesize only event probe point */
- place = synthesize_perf_probe_point(&pev->point);
- if (!place)
- return -EINVAL;
+ if (asprintf(&buf, "%s:%s", group, event) < 0)
+ return -errno;
+ strbuf_addf(result, " %-20s (on ", buf);
+ free(buf);

- ret = e_snprintf(buf, 128, "%s:%s", group, event);
- if (ret < 0)
- goto out;
+ /* Synthesize only event probe point */
+ buf = synthesize_perf_probe_point(&pev->point);
+ if (!buf)
+ return -ENOMEM;
+ strbuf_addstr(result, buf);
+ free(buf);

- strbuf_addf(result, " %-20s (on %s", buf, place);
if (module)
strbuf_addf(result, " in %s", module);

if (pev->nargs > 0) {
strbuf_add(result, " with", 5);
for (i = 0; i < pev->nargs; i++) {
- ret = synthesize_perf_probe_arg(&pev->args[i],
- buf, 128);
- if (ret < 0)
- goto out;
+ buf = synthesize_perf_probe_arg(&pev->args[i]);
+ if (!buf)
+ return -ENOMEM;
strbuf_addf(result, " %s", buf);
+ free(buf);
}
}
strbuf_addch(result, ')');
-out:
- free(place);
- return ret;
+
+ return 0;
}

/* Show an event */
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index e54e7b0..e220962 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -120,7 +120,7 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev);
/* Events to command string */
char *synthesize_perf_probe_command(struct perf_probe_event *pev);
char *synthesize_probe_trace_command(struct probe_trace_event *tev);
-int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf, size_t len);
+char *synthesize_perf_probe_arg(struct perf_probe_arg *pa);

/* Check the perf_probe_event needs debuginfo */
bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b3bd0fb..9f68875 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -553,7 +553,7 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
{
Dwarf_Die vr_die;
- char buf[32], *ptr;
+ char *buf, *ptr;
int ret = 0;

/* Copy raw parameters */
@@ -563,13 +563,13 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
if (pf->pvar->name)
pf->tvar->name = strdup(pf->pvar->name);
else {
- ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
- if (ret < 0)
- return ret;
+ buf = synthesize_perf_probe_arg(pf->pvar);
+ if (!buf)
+ return -ENOMEM;
ptr = strchr(buf, ':'); /* Change type separator to _ */
if (ptr)
*ptr = '_';
- pf->tvar->name = strdup(buf);
+ pf->tvar->name = buf;
}
if (pf->tvar->name == NULL)
return -ENOMEM;
@@ -1334,8 +1334,8 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
if (ret2 == 0) {
strlist__add(vl->vars,
strbuf_detach(&buf, NULL));
- }
- strbuf_release(&buf);
+ } else
+ strbuf_release(&buf);
}
}