| Message ID | 20211104170433.2206-5-beaub@linux.microsoft.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | user_events: Enable user processes to create and write to trace events | expand |
On Thu, 4 Nov 2021 10:04:27 -0700 Beau Belgrave <beaub@linux.microsoft.com> wrote: > Ensures that when dynamic events requests a match with arguments that > they match what is in the user_event. > > Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> > --- > kernel/trace/trace_events_user.c | 67 +++++++++++++++++++++++++++++++- > 1 file changed, 66 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c > index 479a9ced3281..cd78cc481557 100644 > --- a/kernel/trace/trace_events_user.c > +++ b/kernel/trace/trace_events_user.c > @@ -662,13 +662,78 @@ static int user_event_free(struct dyn_event *ev) > return destroy_user_event(user); > } > > +static int user_field_match(struct ftrace_event_field *field, int argc, > + const char **argv, int *iout) > +{ > + char field_name[256]; > + char arg_name[256]; I'm a bit nervous about allocating that much on the stack. This isn't a critical function. I think it is best to just kmalloc it, and fail in the unlikely event that the kmalloc fails. It should never fail unless there's major memory issues with the system. -- Steve > + int len, pos, i = *iout; > + bool colon = false; > + > + if (i >= argc) > + return false; > + > + len = sizeof(arg_name); > + pos = 0; > + > + for (; i < argc; ++i) { > + if (i != *iout) > + pos += snprintf(arg_name + pos, len - pos, " "); > + > + pos += snprintf(arg_name + pos, len - pos, argv[i]); > + > + if (strchr(argv[i], ';')) { > + ++i; > + colon = true; > + break; > + } > + } > + > + len = sizeof(field_name); > + pos = 0; > + > + pos += snprintf(field_name + pos, len - pos, field->type); > + pos += snprintf(field_name + pos, len - pos, " "); > + pos += snprintf(field_name + pos, len - pos, field->name); > + > + if (colon) > + pos += snprintf(field_name + pos, len - pos, ";"); > + > + *iout = i; > + > + return strcmp(arg_name, field_name) == 0; > +} > + > +static bool user_fields_match(struct user_event *user, int argc, > + const char **argv) > +{ > + struct ftrace_event_field *field, *next; > + struct list_head *head = &user->fields; > + int i = 0; > + > + list_for_each_entry_safe_reverse(field, next, head, link) > + if (!user_field_match(field, argc, argv, &i)) > + return false; > + > + if (i != argc) > + return false; > + > + return true; > +} > + > static bool user_event_match(const char *system, const char *event, > int argc, const char **argv, struct dyn_event *ev) > { > struct user_event *user = container_of(ev, struct user_event, devent); > + bool match; > > - return strcmp(EVENT_NAME(user), event) == 0 && > + match = strcmp(EVENT_NAME(user), event) == 0 && > (!system || strcmp(system, USER_EVENTS_SYSTEM) == 0); > + > + if (match && argc > 0) > + match = user_fields_match(user, argc, argv); > + > + return match; > } > > static struct dyn_event_operations user_event_dops = {
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 479a9ced3281..cd78cc481557 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -662,13 +662,78 @@ static int user_event_free(struct dyn_event *ev) return destroy_user_event(user); } +static int user_field_match(struct ftrace_event_field *field, int argc, + const char **argv, int *iout) +{ + char field_name[256]; + char arg_name[256]; + int len, pos, i = *iout; + bool colon = false; + + if (i >= argc) + return false; + + len = sizeof(arg_name); + pos = 0; + + for (; i < argc; ++i) { + if (i != *iout) + pos += snprintf(arg_name + pos, len - pos, " "); + + pos += snprintf(arg_name + pos, len - pos, argv[i]); + + if (strchr(argv[i], ';')) { + ++i; + colon = true; + break; + } + } + + len = sizeof(field_name); + pos = 0; + + pos += snprintf(field_name + pos, len - pos, field->type); + pos += snprintf(field_name + pos, len - pos, " "); + pos += snprintf(field_name + pos, len - pos, field->name); + + if (colon) + pos += snprintf(field_name + pos, len - pos, ";"); + + *iout = i; + + return strcmp(arg_name, field_name) == 0; +} + +static bool user_fields_match(struct user_event *user, int argc, + const char **argv) +{ + struct ftrace_event_field *field, *next; + struct list_head *head = &user->fields; + int i = 0; + + list_for_each_entry_safe_reverse(field, next, head, link) + if (!user_field_match(field, argc, argv, &i)) + return false; + + if (i != argc) + return false; + + return true; +} + static bool user_event_match(const char *system, const char *event, int argc, const char **argv, struct dyn_event *ev) { struct user_event *user = container_of(ev, struct user_event, devent); + bool match; - return strcmp(EVENT_NAME(user), event) == 0 && + match = strcmp(EVENT_NAME(user), event) == 0 && (!system || strcmp(system, USER_EVENTS_SYSTEM) == 0); + + if (match && argc > 0) + match = user_fields_match(user, argc, argv); + + return match; } static struct dyn_event_operations user_event_dops = {
Ensures that when dynamic events requests a match with arguments that they match what is in the user_event. Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> --- kernel/trace/trace_events_user.c | 67 +++++++++++++++++++++++++++++++- 1 file changed, 66 insertions(+), 1 deletion(-)