[tip:perf/core] tools lib traceevent: Use asprintf when possible

From: tip-bot for Federico Vaga
Date: Wed Jan 17 2018 - 11:33:30 EST


Commit-ID: 67dfc376f3dfdc39b9125f32d5b24053a4da264f
Gitweb: https://git.kernel.org/tip/67dfc376f3dfdc39b9125f32d5b24053a4da264f
Author: Federico Vaga <federico.vaga@xxxxxxxxxx>
AuthorDate: Thu, 11 Jan 2018 19:47:48 -0500
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 17 Jan 2018 10:22:19 -0300

tools lib traceevent: Use asprintf when possible

It makes the code clearer and less error prone.

clearer:
- less code
- the code is now using the same format to create strings dynamically

less error prone:
- no magic number +2 +9 +5 to compute the size
- no copy&paste of the strings to compute the size and to concatenate

The function `asprintf` is not POSIX standard but the program
was already using it. Later it can be decided to use only POSIX
functions, then we can easly replace all the `asprintf(3)` with a local
implementation of that function.

Signed-off-by: Federico Vaga <federico.vaga@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Federico Vaga <federico.vaga@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170802221558.9684-2-federico.vaga@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20180112004822.686281649@xxxxxxxxxxx
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/lib/traceevent/event-plugin.c | 24 +++++++++---------------
tools/lib/traceevent/parse-filter.c | 11 ++++-------
2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/tools/lib/traceevent/event-plugin.c b/tools/lib/traceevent/event-plugin.c
index a16756a..d542cb6 100644
--- a/tools/lib/traceevent/event-plugin.c
+++ b/tools/lib/traceevent/event-plugin.c
@@ -120,12 +120,12 @@ char **traceevent_plugin_list_options(void)
for (op = reg->options; op->name; op++) {
char *alias = op->plugin_alias ? op->plugin_alias : op->file;
char **temp = list;
+ int ret;

- name = malloc(strlen(op->name) + strlen(alias) + 2);
- if (!name)
+ ret = asprintf(&name, "%s:%s", alias, op->name);
+ if (ret < 0)
goto err;

- sprintf(name, "%s:%s", alias, op->name);
list = realloc(list, count + 2);
if (!list) {
list = temp;
@@ -290,17 +290,14 @@ load_plugin(struct pevent *pevent, const char *path,
const char *alias;
char *plugin;
void *handle;
+ int ret;

- plugin = malloc(strlen(path) + strlen(file) + 2);
- if (!plugin) {
+ ret = asprintf(&plugin, "%s/%s", path, file);
+ if (ret < 0) {
warning("could not allocate plugin memory\n");
return;
}

- strcpy(plugin, path);
- strcat(plugin, "/");
- strcat(plugin, file);
-
handle = dlopen(plugin, RTLD_NOW | RTLD_GLOBAL);
if (!handle) {
warning("could not load plugin '%s'\n%s\n",
@@ -391,6 +388,7 @@ load_plugins(struct pevent *pevent, const char *suffix,
char *home;
char *path;
char *envdir;
+ int ret;

if (pevent->flags & PEVENT_DISABLE_PLUGINS)
return;
@@ -421,16 +419,12 @@ load_plugins(struct pevent *pevent, const char *suffix,
if (!home)
return;

- path = malloc(strlen(home) + strlen(LOCAL_PLUGIN_DIR) + 2);
- if (!path) {
+ ret = asprintf(&path, "%s/%s", home, LOCAL_PLUGIN_DIR);
+ if (ret < 0) {
warning("could not allocate plugin memory\n");
return;
}

- strcpy(path, home);
- strcat(path, "/");
- strcat(path, LOCAL_PLUGIN_DIR);
-
load_plugins_dir(pevent, suffix, path, load_plugin, data);

free(path);
diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 315df0a..2410afd 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -287,12 +287,10 @@ find_event(struct pevent *pevent, struct event_list **events,
sys_name = NULL;
}

- reg = malloc(strlen(event_name) + 3);
- if (reg == NULL)
+ ret = asprintf(&reg, "^%s$", event_name);
+ if (ret < 0)
return PEVENT_ERRNO__MEM_ALLOC_FAILED;

- sprintf(reg, "^%s$", event_name);
-
ret = regcomp(&ereg, reg, REG_ICASE|REG_NOSUB);
free(reg);

@@ -300,13 +298,12 @@ find_event(struct pevent *pevent, struct event_list **events,
return PEVENT_ERRNO__INVALID_EVENT_NAME;

if (sys_name) {
- reg = malloc(strlen(sys_name) + 3);
- if (reg == NULL) {
+ ret = asprintf(&reg, "^%s$", sys_name);
+ if (ret < 0) {
regfree(&ereg);
return PEVENT_ERRNO__MEM_ALLOC_FAILED;
}

- sprintf(reg, "^%s$", sys_name);
ret = regcomp(&sreg, reg, REG_ICASE|REG_NOSUB);
free(reg);
if (ret) {