nuttx/sched/sched/sched_gettcb.c
Gregory Nutt 4b44b628ea Run nxstyle against all .c and .h files modified by this PR.
All complaints fixed except for those that were not possible to fix:

- Used of Mixed case identifier in ESP32 files.  These are references to Expressif ROM functions which are outside of the scope of NuttX.
2020-05-09 14:19:08 -03:00

79 lines
2.3 KiB
C

/****************************************************************************
* sched/sched/sched_gettcb.c
*
#if CONFIG_NFILE_STREAMS > 0
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <sched.h>
#include "nuttx/irq.h"
#include "sched/sched.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsched_get_tcb
*
* Description:
* Given a task ID, this function will return the a pointer to the
* corresponding TCB (or NULL if there is no such task ID).
*
* NOTE: This function holds a critical section while examining TCB data
* data structures but releases that critical section before returning.
* When it is released, the TCB may become unstable. If the caller
* requires absolute stability while using the TCB, then the caller
* should establish the critical section BEFORE calling this function and
* hold that critical section as long as necessary.
*
****************************************************************************/
FAR struct tcb_s *nxsched_get_tcb(pid_t pid)
{
FAR struct tcb_s *ret = NULL;
irqstate_t flags;
int hash_ndx;
/* Verify that the PID is within range */
if (pid >= 0)
{
/* Get the hash_ndx associated with the pid */
hash_ndx = PIDHASH(pid);
/* The test and the return setup should be atomic. This still does
* not provide proper protection if the recipient of the TCB does not
* also protect against the task associated with the TCB from
* terminating asynchronously.
*/
flags = enter_critical_section();
/* Verify that the correct TCB was found. */
if (pid == g_pidhash[hash_ndx].pid)
{
/* Return the TCB associated with this pid (if any) */
ret = g_pidhash[hash_ndx].tcb;
}
leave_critical_section(flags);
}
/* Return the TCB. */
return ret;
}