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tracing/dynevent: Delegate parsing to create function
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Delegate command parsing to each create function so that the
command syntax can be customized.

This requires changes to the kprobe/uprobe/synthetic event handling,
which are also included here.

Link: https://lkml.kernel.org/r/e488726f49cbdbc01568618f8680584306c4c79f.1612208610.git.zanussi@kernel.org

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
[ zanussi@kernel.org: added synthetic event modifications ]
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Masami Hiramatsu authored and Steven Rostedt (VMware) committed Feb 9, 2021
1 parent 33b1d14 commit d262271
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Showing 9 changed files with 120 additions and 73 deletions.
23 changes: 2 additions & 21 deletions kernel/trace/trace.c
Original file line number Diff line number Diff line change
Expand Up @@ -9412,30 +9412,11 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
}
EXPORT_SYMBOL_GPL(ftrace_dump);

int trace_run_command(const char *buf, int (*createfn)(int, char **))
{
char **argv;
int argc, ret;

argc = 0;
ret = 0;
argv = argv_split(GFP_KERNEL, buf, &argc);
if (!argv)
return -ENOMEM;

if (argc)
ret = createfn(argc, argv);

argv_free(argv);

return ret;
}

#define WRITE_BUFSIZE 4096

ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos,
int (*createfn)(int, char **))
int (*createfn)(const char *))
{
char *kbuf, *buf, *tmp;
int ret = 0;
Expand Down Expand Up @@ -9483,7 +9464,7 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
if (tmp)
*tmp = '\0';

ret = trace_run_command(buf, createfn);
ret = createfn(buf);
if (ret)
goto out;
buf += size;
Expand Down
3 changes: 1 addition & 2 deletions kernel/trace/trace.h
Original file line number Diff line number Diff line change
Expand Up @@ -1807,10 +1807,9 @@ extern int tracing_set_cpumask(struct trace_array *tr,

#define MAX_EVENT_NAME_LEN 64

extern int trace_run_command(const char *buf, int (*createfn)(int, char**));
extern ssize_t trace_parse_run_command(struct file *file,
const char __user *buffer, size_t count, loff_t *ppos,
int (*createfn)(int, char**));
int (*createfn)(const char *));

extern unsigned int err_pos(char *cmd, const char *str);
extern void tracing_log_err(struct trace_array *tr,
Expand Down
35 changes: 22 additions & 13 deletions kernel/trace/trace_dynevent.c
Original file line number Diff line number Diff line change
Expand Up @@ -31,23 +31,31 @@ int dyn_event_register(struct dyn_event_operations *ops)
return 0;
}

int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
int dyn_event_release(const char *raw_command, struct dyn_event_operations *type)
{
struct dyn_event *pos, *n;
char *system = NULL, *event, *p;
int ret = -ENOENT;
int argc, ret = -ENOENT;
char **argv;

argv = argv_split(GFP_KERNEL, raw_command, &argc);
if (!argv)
return -ENOMEM;

if (argv[0][0] == '-') {
if (argv[0][1] != ':')
return -EINVAL;
if (argv[0][1] != ':') {
ret = -EINVAL;
goto out;
}
event = &argv[0][2];
} else {
event = strchr(argv[0], ':');
if (!event)
return -EINVAL;
if (!event) {
ret = -EINVAL;
goto out;
}
event++;
}
argc--; argv++;

p = strchr(event, '/');
if (p) {
Expand All @@ -63,29 +71,30 @@ int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
if (type && type != pos->ops)
continue;
if (!pos->ops->match(system, event,
argc, (const char **)argv, pos))
argc - 1, (const char **)argv + 1, pos))
continue;

ret = pos->ops->free(pos);
if (ret)
break;
}
mutex_unlock(&event_mutex);

out:
argv_free(argv);
return ret;
}

static int create_dyn_event(int argc, char **argv)
static int create_dyn_event(const char *raw_command)
{
struct dyn_event_operations *ops;
int ret = -ENODEV;

if (argv[0][0] == '-' || argv[0][0] == '!')
return dyn_event_release(argc, argv, NULL);
if (raw_command[0] == '-' || raw_command[0] == '!')
return dyn_event_release(raw_command, NULL);

mutex_lock(&dyn_event_ops_mutex);
list_for_each_entry(ops, &dyn_event_ops_list, list) {
ret = ops->create(argc, (const char **)argv);
ret = ops->create(raw_command);
if (!ret || ret != -ECANCELED)
break;
}
Expand Down
4 changes: 2 additions & 2 deletions kernel/trace/trace_dynevent.h
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@ struct dyn_event;
*/
struct dyn_event_operations {
struct list_head list;
int (*create)(int argc, const char *argv[]);
int (*create)(const char *raw_command);
int (*show)(struct seq_file *m, struct dyn_event *ev);
bool (*is_busy)(struct dyn_event *ev);
int (*free)(struct dyn_event *ev);
Expand Down Expand Up @@ -97,7 +97,7 @@ void *dyn_event_seq_start(struct seq_file *m, loff_t *pos);
void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
void dyn_event_seq_stop(struct seq_file *m, void *v);
int dyn_events_release_all(struct dyn_event_operations *type);
int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type);
int dyn_event_release(const char *raw_command, struct dyn_event_operations *type);

/*
* for_each_dyn_event - iterate over the dyn_event list
Expand Down
60 changes: 46 additions & 14 deletions kernel/trace/trace_events_synth.c
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ static void synth_err(u8 err_type, u8 err_pos)
err_type, err_pos);
}

static int create_synth_event(int argc, const char **argv);
static int create_synth_event(const char *raw_command);
static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
static int synth_event_release(struct dyn_event *ev);
static bool synth_event_is_busy(struct dyn_event *ev);
Expand Down Expand Up @@ -1383,18 +1383,30 @@ int synth_event_delete(const char *event_name)
}
EXPORT_SYMBOL_GPL(synth_event_delete);

static int create_or_delete_synth_event(int argc, char **argv)
static int create_or_delete_synth_event(const char *raw_command)
{
const char *name = argv[0];
int ret;
char **argv, *name = NULL;
int argc = 0, ret = 0;

argv = argv_split(GFP_KERNEL, raw_command, &argc);
if (!argv)
return -ENOMEM;

if (!argc)
goto free;

name = argv[0];

/* trace_run_command() ensures argc != 0 */
if (name[0] == '!') {
ret = synth_event_delete(name + 1);
return ret;
goto free;
}

ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
free:
argv_free(argv);

return ret == -ECANCELED ? -EINVAL : ret;
}

Expand All @@ -1403,7 +1415,7 @@ static int synth_event_run_command(struct dynevent_cmd *cmd)
struct synth_event *se;
int ret;

ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
ret = create_or_delete_synth_event(cmd->seq.buffer);
if (ret)
return ret;

Expand Down Expand Up @@ -1939,23 +1951,43 @@ int synth_event_trace_end(struct synth_event_trace_state *trace_state)
}
EXPORT_SYMBOL_GPL(synth_event_trace_end);

static int create_synth_event(int argc, const char **argv)
static int create_synth_event(const char *raw_command)
{
const char *name = argv[0];
int len;
char **argv, *name;
int len, argc = 0, ret = 0;

argv = argv_split(GFP_KERNEL, raw_command, &argc);
if (!argv) {
ret = -ENOMEM;
return ret;
}

if (name[0] != 's' || name[1] != ':')
return -ECANCELED;
if (!argc)
goto free;

name = argv[0];

if (name[0] != 's' || name[1] != ':') {
ret = -ECANCELED;
goto free;
}
name += 2;

/* This interface accepts group name prefix */
if (strchr(name, '/')) {
len = str_has_prefix(name, SYNTH_SYSTEM "/");
if (len == 0)
return -EINVAL;
if (len == 0) {
ret = -EINVAL;
goto free;
}
name += len;
}
return __create_synth_event(argc - 1, name, argv + 1);

ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
free:
argv_free(argv);

return ret;
}

static int synth_event_release(struct dyn_event *ev)
Expand Down
33 changes: 18 additions & 15 deletions kernel/trace/trace_kprobe.c
Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ static int __init set_kprobe_boot_events(char *str)
}
__setup("kprobe_event=", set_kprobe_boot_events);

static int trace_kprobe_create(int argc, const char **argv);
static int trace_kprobe_create(const char *raw_command);
static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
static int trace_kprobe_release(struct dyn_event *ev);
static bool trace_kprobe_is_busy(struct dyn_event *ev);
Expand Down Expand Up @@ -711,7 +711,7 @@ static inline void sanitize_event_name(char *name)
*name = '_';
}

static int trace_kprobe_create(int argc, const char *argv[])
static int __trace_kprobe_create(int argc, const char *argv[])
{
/*
* Argument syntax:
Expand Down Expand Up @@ -910,20 +910,25 @@ static int trace_kprobe_create(int argc, const char *argv[])
goto out;
}

static int create_or_delete_trace_kprobe(int argc, char **argv)
static int trace_kprobe_create(const char *raw_command)
{
return trace_probe_create(raw_command, __trace_kprobe_create);
}

static int create_or_delete_trace_kprobe(const char *raw_command)
{
int ret;

if (argv[0][0] == '-')
return dyn_event_release(argc, argv, &trace_kprobe_ops);
if (raw_command[0] == '-')
return dyn_event_release(raw_command, &trace_kprobe_ops);

ret = trace_kprobe_create(argc, (const char **)argv);
ret = trace_kprobe_create(raw_command);
return ret == -ECANCELED ? -EINVAL : ret;
}

static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
{
return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
return create_or_delete_trace_kprobe(cmd->seq.buffer);
}

/**
Expand Down Expand Up @@ -1084,7 +1089,7 @@ int kprobe_event_delete(const char *name)

snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);

return trace_run_command(buf, create_or_delete_trace_kprobe);
return create_or_delete_trace_kprobe(buf);
}
EXPORT_SYMBOL_GPL(kprobe_event_delete);

Expand Down Expand Up @@ -1886,7 +1891,7 @@ static __init void setup_boot_kprobe_events(void)
if (p)
*p++ = '\0';

ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
ret = create_or_delete_trace_kprobe(cmd);
if (ret)
pr_warn("Failed to add event(%d): %s\n", ret, cmd);

Expand Down Expand Up @@ -1980,8 +1985,7 @@ static __init int kprobe_trace_self_tests_init(void)

pr_info("Testing kprobe tracing: ");

ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
create_or_delete_trace_kprobe);
ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
if (WARN_ON_ONCE(ret)) {
pr_warn("error on probing function entry.\n");
warn++;
Expand All @@ -2002,8 +2006,7 @@ static __init int kprobe_trace_self_tests_init(void)
}
}

ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
create_or_delete_trace_kprobe);
ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
if (WARN_ON_ONCE(ret)) {
pr_warn("error on probing function return.\n");
warn++;
Expand Down Expand Up @@ -2076,13 +2079,13 @@ static __init int kprobe_trace_self_tests_init(void)
trace_probe_event_call(&tk->tp), file);
}

ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
ret = create_or_delete_trace_kprobe("-:testprobe");
if (WARN_ON_ONCE(ret)) {
pr_warn("error on deleting a probe.\n");
warn++;
}

ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
ret = create_or_delete_trace_kprobe("-:testprobe2");
if (WARN_ON_ONCE(ret)) {
pr_warn("error on deleting a probe.\n");
warn++;
Expand Down
17 changes: 17 additions & 0 deletions kernel/trace/trace_probe.c
Original file line number Diff line number Diff line change
Expand Up @@ -1134,3 +1134,20 @@ bool trace_probe_match_command_args(struct trace_probe *tp,
}
return true;
}

int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
{
int argc = 0, ret = 0;
char **argv;

argv = argv_split(GFP_KERNEL, raw_command, &argc);
if (!argv)
return -ENOMEM;

if (argc)
ret = createfn(argc, (const char **)argv);

argv_free(argv);

return ret;
}
1 change: 1 addition & 0 deletions kernel/trace/trace_probe.h
Original file line number Diff line number Diff line change
Expand Up @@ -341,6 +341,7 @@ struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
bool trace_probe_match_command_args(struct trace_probe *tp,
int argc, const char **argv);
int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **));

#define trace_probe_for_each_link(pos, tp) \
list_for_each_entry(pos, &(tp)->event->files, list)
Expand Down
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