injection_points.c File Reference

#include "postgres.h"
#include "fmgr.h"
#include "miscadmin.h"
#include "storage/condition_variable.h"
#include "storage/dsm_registry.h"
#include "storage/ipc.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#include "utils/builtins.h"
#include "utils/injection_point.h"
#include "utils/wait_event.h"

Include dependency graph for injection_points.c:

Go to the source code of this file.

Data Structures
struct	InjectionPointCondition
struct	InjectionPointSharedState

Macros
#define	INJ_MAX_WAIT   8
#define	INJ_NAME_MAXLEN   64
#define	INJ_MAX_CONDITION   4

Typedefs
typedef struct InjectionPointCondition	InjectionPointCondition
typedef struct InjectionPointSharedState	InjectionPointSharedState

Functions
PGDLLEXPORT void	injection_error (const char *name)
PGDLLEXPORT void	injection_notice (const char *name)
PGDLLEXPORT void	injection_wait (const char *name)
static void	injection_point_init_state (void *ptr)
static void	injection_init_shmem (void)
static bool	injection_point_allowed (const char *name)
static void	injection_points_cleanup (int code, Datum arg)
	PG_FUNCTION_INFO_V1 (injection_points_attach)
Datum	injection_points_attach (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (injection_points_run)
Datum	injection_points_run (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (injection_points_wakeup)
Datum	injection_points_wakeup (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (injection_points_set_local)
Datum	injection_points_set_local (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (injection_points_detach)
Datum	injection_points_detach (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC
static InjectionPointSharedState *	inj_state = NULL
static bool	injection_point_local = false

Macro Definition Documentation

INJ_MAX_CONDITION

#define INJ_MAX_CONDITION   4

Definition at line 36 of file injection_points.c.

INJ_MAX_WAIT

#define INJ_MAX_WAIT   8

Definition at line 34 of file injection_points.c.

INJ_NAME_MAXLEN

#define INJ_NAME_MAXLEN   64

Definition at line 35 of file injection_points.c.

Typedef Documentation

InjectionPointCondition

typedef struct InjectionPointCondition InjectionPointCondition

InjectionPointSharedState

typedef struct InjectionPointSharedState InjectionPointSharedState

Function Documentation

injection_error()

void injection_error

(

const char *

name

)

Definition at line 214 of file injection_points.c.

{
    if (!injection_point_allowed(name))
        return;
 
    elog(ERROR, "error triggered for injection point %s", name);
}

References elog, ERROR, injection_point_allowed(), and name.

injection_init_shmem()

static void injection_init_shmem ( void  )

static

Definition at line 102 of file injection_points.c.

{
    bool        found;
 
    if (inj_state != NULL)
        return;
 
    inj_state = GetNamedDSMSegment("injection_points",
                                   sizeof(InjectionPointSharedState),
                                   injection_point_init_state,
                                   &found);
}

References GetNamedDSMSegment(), inj_state, and injection_point_init_state().

Referenced by injection_point_allowed(), injection_points_detach(), injection_points_set_local(), injection_points_wakeup(), and injection_wait().

injection_notice()

void injection_notice

(

const char *

name

)

Definition at line 223 of file injection_points.c.

{
    if (!injection_point_allowed(name))
        return;
 
    elog(NOTICE, "notice triggered for injection point %s", name);
}

References elog, injection_point_allowed(), name, and NOTICE.

injection_point_allowed()

static bool injection_point_allowed ( const char *  name )

static

Definition at line 123 of file injection_points.c.

{
    bool        result = true;
 
    if (inj_state == NULL)
        injection_init_shmem();
 
    SpinLockAcquire(&inj_state->lock);
 
    for (int i = 0; i < INJ_MAX_CONDITION; i++)
    {
        InjectionPointCondition *condition = &inj_state->conditions[i];
 
        if (strcmp(condition->name, name) == 0)
        {
            /*
             * Check if this injection point is allowed to run in this
             * process.
             */
            if (MyProcPid != condition->pid)
            {
                result = false;
                break;
            }
        }
    }
 
    SpinLockRelease(&inj_state->lock);
 
    return result;
}

References InjectionPointSharedState::conditions, i, INJ_MAX_CONDITION, inj_state, injection_init_shmem(), InjectionPointSharedState::lock, MyProcPid, name, InjectionPointCondition::name, InjectionPointCondition::pid, SpinLockAcquire, and SpinLockRelease.

Referenced by injection_error(), injection_notice(), and injection_wait().

injection_point_init_state()

static void injection_point_init_state ( void *  ptr )

static

Definition at line 87 of file injection_points.c.

{
    InjectionPointSharedState *state = (InjectionPointSharedState *) ptr;
 
    SpinLockInit(&state->lock);
    memset(state->wait_counts, 0, sizeof(state->wait_counts));
    memset(state->name, 0, sizeof(state->name));
    memset(state->conditions, 0, sizeof(state->conditions));
    ConditionVariableInit(&state->wait_point);
}

References ConditionVariableInit(), and SpinLockInit.

Referenced by injection_init_shmem().

injection_points_attach()

Datum injection_points_attach

(

PG_FUNCTION_ARGS

)

Definition at line 299 of file injection_points.c.

{
    char       *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
    char       *action = text_to_cstring(PG_GETARG_TEXT_PP(1));
    char       *function;
 
    if (strcmp(action, "error") == 0)
        function = "injection_error";
    else if (strcmp(action, "notice") == 0)
        function = "injection_notice";
    else if (strcmp(action, "wait") == 0)
        function = "injection_wait";
    else
        elog(ERROR, "incorrect action \"%s\" for injection point creation", action);
 
    InjectionPointAttach(name, "injection_points", function);
 
    if (injection_point_local)
    {
        int         index = -1;
 
        /*
         * Register runtime condition to link this injection point to the
         * current process.
         */
        SpinLockAcquire(&inj_state->lock);
        for (int i = 0; i < INJ_MAX_CONDITION; i++)
        {
            InjectionPointCondition *condition = &inj_state->conditions[i];
 
            if (condition->name[0] == '\0')
            {
                index = i;
                strlcpy(condition->name, name, INJ_NAME_MAXLEN);
                condition->pid = MyProcPid;
                break;
            }
        }
        SpinLockRelease(&inj_state->lock);
 
        if (index < 0)
            elog(FATAL,
                 "could not find free slot for condition of injection point %s",
                 name);
    }
 
    PG_RETURN_VOID();
}

References generate_unaccent_rules::action, InjectionPointSharedState::conditions, elog, ERROR, FATAL, i, INJ_MAX_CONDITION, INJ_NAME_MAXLEN, inj_state, injection_point_local, InjectionPointAttach(), InjectionPointSharedState::lock, MyProcPid, name, InjectionPointCondition::name, PG_GETARG_TEXT_PP, PG_RETURN_VOID, InjectionPointCondition::pid, SpinLockAcquire, SpinLockRelease, strlcpy(), and text_to_cstring().

injection_points_cleanup()

static void injection_points_cleanup ( int  code, Datum  arg  )

static

Definition at line 160 of file injection_points.c.

{
    char        names[INJ_MAX_CONDITION][INJ_NAME_MAXLEN] = {0};
    int         count = 0;
 
    /* Leave if nothing is tracked locally */
    if (!injection_point_local)
        return;
 
    /*
     * This is done in three steps: detect the points to detach, detach them
     * and release their conditions.
     */
    SpinLockAcquire(&inj_state->lock);
    for (int i = 0; i < INJ_MAX_CONDITION; i++)
    {
        InjectionPointCondition *condition = &inj_state->conditions[i];
 
        if (condition->name[0] == '\0')
            continue;
 
        if (condition->pid != MyProcPid)
            continue;
 
        /* Extract the point name to detach */
        strlcpy(names[count], condition->name, INJ_NAME_MAXLEN);
        count++;
    }
    SpinLockRelease(&inj_state->lock);
 
    /* Detach, without holding the spinlock */
    for (int i = 0; i < count; i++)
        InjectionPointDetach(names[i]);
 
    /* Clear all the conditions */
    SpinLockAcquire(&inj_state->lock);
    for (int i = 0; i < INJ_MAX_CONDITION; i++)
    {
        InjectionPointCondition *condition = &inj_state->conditions[i];
 
        if (condition->name[0] == '\0')
            continue;
 
        if (condition->pid != MyProcPid)
            continue;
 
        condition->name[0] = '\0';
        condition->pid = 0;
    }
    SpinLockRelease(&inj_state->lock);
}

References InjectionPointSharedState::conditions, i, INJ_MAX_CONDITION, INJ_NAME_MAXLEN, inj_state, injection_point_local, InjectionPointDetach(), InjectionPointSharedState::lock, MyProcPid, InjectionPointCondition::name, InjectionPointCondition::pid, SpinLockAcquire, SpinLockRelease, and strlcpy().

Referenced by injection_points_set_local().

injection_points_detach()

Datum injection_points_detach

(

PG_FUNCTION_ARGS

)

Definition at line 429 of file injection_points.c.

{
    char       *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
    InjectionPointDetach(name);
 
    if (inj_state == NULL)
        injection_init_shmem();
 
    /* Clean up any conditions associated to this injection point */
    SpinLockAcquire(&inj_state->lock);
    for (int i = 0; i < INJ_MAX_CONDITION; i++)
    {
        InjectionPointCondition *condition = &inj_state->conditions[i];
 
        if (strcmp(condition->name, name) == 0)
        {
            condition->pid = 0;
            condition->name[0] = '\0';
        }
    }
    SpinLockRelease(&inj_state->lock);
 
    PG_RETURN_VOID();
}

References InjectionPointSharedState::conditions, i, INJ_MAX_CONDITION, inj_state, injection_init_shmem(), InjectionPointDetach(), InjectionPointSharedState::lock, name, InjectionPointCondition::name, PG_GETARG_TEXT_PP, PG_RETURN_VOID, InjectionPointCondition::pid, SpinLockAcquire, SpinLockRelease, and text_to_cstring().

injection_points_run()

Datum injection_points_run

(

PG_FUNCTION_ARGS

)

Definition at line 353 of file injection_points.c.

{
    char       *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
    INJECTION_POINT(name);
 
    PG_RETURN_VOID();
}

References INJECTION_POINT, name, PG_GETARG_TEXT_PP, PG_RETURN_VOID, and text_to_cstring().

injection_points_set_local()

Datum injection_points_set_local

(

PG_FUNCTION_ARGS

)

Definition at line 407 of file injection_points.c.

{
    /* Enable flag to add a runtime condition based on this process ID */
    injection_point_local = true;
 
    if (inj_state == NULL)
        injection_init_shmem();
 
    /*
     * Register a before_shmem_exit callback to remove any injection points
     * linked to this process.
     */
    before_shmem_exit(injection_points_cleanup, (Datum) 0);
 
    PG_RETURN_VOID();
}

References before_shmem_exit(), inj_state, injection_init_shmem(), injection_point_local, injection_points_cleanup(), and PG_RETURN_VOID.

injection_points_wakeup()

Datum injection_points_wakeup

(

PG_FUNCTION_ARGS

)

Definition at line 367 of file injection_points.c.

{
    char       *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
    int         index = -1;
 
    if (inj_state == NULL)
        injection_init_shmem();
 
    /* First bump the wait counter for the injection point to wake up */
    SpinLockAcquire(&inj_state->lock);
    for (int i = 0; i < INJ_MAX_WAIT; i++)
    {
        if (strcmp(name, inj_state->name[i]) == 0)
        {
            index = i;
            break;
        }
    }
    if (index < 0)
    {
        SpinLockRelease(&inj_state->lock);
        elog(ERROR, "could not find injection point %s to wake up", name);
    }
    inj_state->wait_counts[index]++;
    SpinLockRelease(&inj_state->lock);
 
    /* And broadcast the change to the waiters */
    ConditionVariableBroadcast(&inj_state->wait_point);
    PG_RETURN_VOID();
}

References ConditionVariableBroadcast(), elog, ERROR, i, INJ_MAX_WAIT, inj_state, injection_init_shmem(), InjectionPointSharedState::lock, name, InjectionPointSharedState::name, PG_GETARG_TEXT_PP, PG_RETURN_VOID, SpinLockAcquire, SpinLockRelease, text_to_cstring(), InjectionPointSharedState::wait_counts, and InjectionPointSharedState::wait_point.

injection_wait()

void injection_wait

(

const char *

name

)

Definition at line 233 of file injection_points.c.

{
    uint32      old_wait_counts = 0;
    int         index = -1;
    uint32      injection_wait_event = 0;
 
    if (inj_state == NULL)
        injection_init_shmem();
 
    if (!injection_point_allowed(name))
        return;
 
    /*
     * Use the injection point name for this custom wait event.  Note that
     * this custom wait event name is not released, but we don't care much for
     * testing as this should be short-lived.
     */
    injection_wait_event = WaitEventExtensionNew(name);
 
    /*
     * Find a free slot to wait for, and register this injection point's name.
     */
    SpinLockAcquire(&inj_state->lock);
    for (int i = 0; i < INJ_MAX_WAIT; i++)
    {
        if (inj_state->name[i][0] == '\0')
        {
            index = i;
            strlcpy(inj_state->name[i], name, INJ_NAME_MAXLEN);
            old_wait_counts = inj_state->wait_counts[i];
            break;
        }
    }
    SpinLockRelease(&inj_state->lock);
 
    if (index < 0)
        elog(ERROR, "could not find free slot for wait of injection point %s ",
             name);
 
    /* And sleep.. */
    ConditionVariablePrepareToSleep(&inj_state->wait_point);
    for (;;)
    {
        uint32      new_wait_counts;
 
        SpinLockAcquire(&inj_state->lock);
        new_wait_counts = inj_state->wait_counts[index];
        SpinLockRelease(&inj_state->lock);
 
        if (old_wait_counts != new_wait_counts)
            break;
        ConditionVariableSleep(&inj_state->wait_point, injection_wait_event);
    }
    ConditionVariableCancelSleep();
 
    /* Remove this injection point from the waiters. */
    SpinLockAcquire(&inj_state->lock);
    inj_state->name[index][0] = '\0';
    SpinLockRelease(&inj_state->lock);
}

References ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableSleep(), elog, ERROR, i, INJ_MAX_WAIT, INJ_NAME_MAXLEN, inj_state, injection_init_shmem(), injection_point_allowed(), InjectionPointSharedState::lock, name, InjectionPointSharedState::name, SpinLockAcquire, SpinLockRelease, strlcpy(), InjectionPointSharedState::wait_counts, InjectionPointSharedState::wait_point, and WaitEventExtensionNew().

PG_FUNCTION_INFO_V1() [1/5]

PG_FUNCTION_INFO_V1

(

injection_points_attach

)

PG_FUNCTION_INFO_V1() [2/5]

PG_FUNCTION_INFO_V1

(

injection_points_detach

)

PG_FUNCTION_INFO_V1() [3/5]

PG_FUNCTION_INFO_V1

(

injection_points_run

)

PG_FUNCTION_INFO_V1() [4/5]

PG_FUNCTION_INFO_V1

(

injection_points_set_local

)

PG_FUNCTION_INFO_V1() [5/5]

PG_FUNCTION_INFO_V1

(

injection_points_wakeup

)

Variable Documentation

inj_state

InjectionPointSharedState* inj_state = NULL

static

Definition at line 74 of file injection_points.c.

Referenced by injection_init_shmem(), injection_point_allowed(), injection_points_attach(), injection_points_cleanup(), injection_points_detach(), injection_points_set_local(), injection_points_wakeup(), and injection_wait().

injection_point_local

bool injection_point_local = false

static

Definition at line 81 of file injection_points.c.

Referenced by injection_points_attach(), injection_points_cleanup(), and injection_points_set_local().

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 31 of file injection_points.c.