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tracing/syscalls: Init print_fmt for syscall events

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This is part of a patch set that removes the show_format method
in the ftrace event macros.

Add the print_fmt initialization to the syscall events.
The print_fmt is still not used, but will be in the follow up
patches.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D41.609@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Lai Jiangshan 2009-12-15 15:39:45 +08:00 committed by Steven Rostedt
parent 509e760cd9
commit 50307a45f8
1 changed files with 67 additions and 1 deletions
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68
kernel/trace/trace_syscalls.c
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@ -191,6 +191,67 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
return trace_seq_putc(s, '\n');
}
static
int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
{
int i;
int pos = 0;
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < entry->nb_args; i++) {
pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
entry->args[i], sizeof(unsigned long),
i == entry->nb_args - 1 ? "" : ", ");
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < entry->nb_args; i++) {
pos += snprintf(buf + pos, LEN_OR_ZERO,
", ((unsigned long)(REC->%s))", entry->args[i]);
}
#undef LEN_OR_ZERO
/* return the length of print_fmt */
return pos;
}
static int set_syscall_print_fmt(struct ftrace_event_call *call)
{
char *print_fmt;
int len;
struct syscall_metadata *entry = call->data;
if (entry->enter_event != call) {
call->print_fmt = "\"0x%lx\", REC->ret";
return 0;
}
/* First: called with 0 length to calculate the needed length */
len = __set_enter_print_fmt(entry, NULL, 0);
print_fmt = kmalloc(len + 1, GFP_KERNEL);
if (!print_fmt)
return -ENOMEM;
/* Second: actually write the @print_fmt */
__set_enter_print_fmt(entry, print_fmt, len + 1);
call->print_fmt = print_fmt;
return 0;
}
static void free_syscall_print_fmt(struct ftrace_event_call *call)
{
struct syscall_metadata *entry = call->data;
if (entry->enter_event == call)
kfree(call->print_fmt);
}
int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
{
int ret;
@ -386,9 +447,14 @@ int init_syscall_trace(struct ftrace_event_call *call)
{
int id;
if (set_syscall_print_fmt(call) < 0)
return -ENOMEM;
id = register_ftrace_event(call->event);
if (!id)
if (!id) {
free_syscall_print_fmt(call);
return -ENODEV;
}
call->id = id;
INIT_LIST_HEAD(&call->fields);
return 0;