probes/lttng-context-pid.c

   1 /*
   2  * (C) Copyright        2009-2011 -
   3  *              Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * LTTng PID context.
   6  *
   7  * Dual LGPL v2.1/GPL v2 license.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/sched.h>
  13 #include "../ltt-events.h"
  14 #include "../wrapper/ringbuffer/frontend_types.h"
  15 #include "../wrapper/vmalloc.h"
  16 #include "../ltt-tracer.h"
  17
  18 static
  19 void pid_record(struct lttng_ctx_field *field,
  20                 struct lib_ring_buffer_ctx *ctx,
  21                 struct ltt_channel *chan)
  22 {
  23         pid_t pid;
  24
  25         pid = current->pid;
  26         lib_ring_buffer_align_ctx(ctx, ltt_alignof(pid));
  27         chan->ops->event_write(ctx, &pid, sizeof(pid));
  28 }
  29
  30 int lttng_add_pid_to_ctx(struct lttng_ctx **ctx)
  31 {
  32         struct lttng_ctx_field *field;
  33         int ret;
  34
  35         field = lttng_append_context(ctx);
  36         if (!field)
  37                 return ret;
  38         field->name = "pid";
  39         field->type.atype = atype_integer;
  40         field->type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
  41         field->type.u.basic.integer.alignment = ltt_alignof(pid_t) * CHAR_BIT;
  42         field->type.u.basic.integer.signedness = is_signed_type(pid_t);
  43         field->type.u.basic.integer.reverse_byte_order = 0;
  44         field->type.u.basic.integer.base = 10;
  45         field->type.u.basic.integer.encoding = lttng_encode_none;
  46         field->callback = pid_record;
  47         wrapper_vmalloc_sync_all();
  48         return 0;
  49 }
  50
  51 MODULE_LICENSE("GPL and additional rights");
  52 MODULE_AUTHOR("Mathieu Desnoyers");
  53 MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");