PostgreSQL Source Code  git master
ipc.c File Reference
#include "postgres.h"
#include <signal.h>
#include <unistd.h>
#include <sys/stat.h>
#include "miscadmin.h"
#include "storage/dsm.h"
#include "storage/ipc.h"
#include "tcop/tcopprot.h"
Include dependency graph for ipc.c:

Go to the source code of this file.

Data Structures

struct  ONEXIT
 

Macros

#define MAX_ON_EXITS   20
 

Functions

static void proc_exit_prepare (int code)
 
void proc_exit (int code)
 
void shmem_exit (int code)
 
static void atexit_callback (void)
 
void on_proc_exit (pg_on_exit_callback function, Datum arg)
 
void before_shmem_exit (pg_on_exit_callback function, Datum arg)
 
void on_shmem_exit (pg_on_exit_callback function, Datum arg)
 
void cancel_before_shmem_exit (pg_on_exit_callback function, Datum arg)
 
void on_exit_reset (void)
 

Variables

bool proc_exit_inprogress = false
 
bool shmem_exit_inprogress = false
 
static bool atexit_callback_setup = false
 
static struct ONEXIT on_proc_exit_list [MAX_ON_EXITS]
 
static struct ONEXIT on_shmem_exit_list [MAX_ON_EXITS]
 
static struct ONEXIT before_shmem_exit_list [MAX_ON_EXITS]
 
static int on_proc_exit_index
 
static int on_shmem_exit_index
 
static int before_shmem_exit_index
 

Macro Definition Documentation

◆ MAX_ON_EXITS

#define MAX_ON_EXITS   20

Definition at line 71 of file ipc.c.

Referenced by before_shmem_exit(), on_proc_exit(), and on_shmem_exit().

Function Documentation

◆ atexit_callback()

static void atexit_callback ( void  )
static

Definition at line 284 of file ipc.c.

References proc_exit_prepare().

Referenced by before_shmem_exit(), on_proc_exit(), and on_shmem_exit().

285 {
286  /* Clean up everything that must be cleaned up */
287  /* ... too bad we don't know the real exit code ... */
288  proc_exit_prepare(-1);
289 }
static void proc_exit_prepare(int code)
Definition: ipc.c:157

◆ before_shmem_exit()

void before_shmem_exit ( pg_on_exit_callback  function,
Datum  arg 
)

Definition at line 327 of file ipc.c.

References ONEXIT::arg, atexit_callback(), atexit_callback_setup, before_shmem_exit_index, before_shmem_exit_list, ereport, errcode(), errmsg_internal(), FATAL, ONEXIT::function, and MAX_ON_EXITS.

Referenced by ApplyLauncherMain(), AtEOXact_Namespace(), AuxiliaryProcessMain(), Exec_ListenPreCommit(), InitPostgres(), LockGXact(), logicalrep_worker_attach(), MarkAsPreparing(), and pg_start_backup().

328 {
330  ereport(FATAL,
331  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
332  errmsg_internal("out of before_shmem_exit slots")));
333 
336 
338 
340  {
341  atexit(atexit_callback);
342  atexit_callback_setup = true;
343  }
344 }
#define MAX_ON_EXITS
Definition: ipc.c:71
int errcode(int sqlerrcode)
Definition: elog.c:575
pg_on_exit_callback function
Definition: ipc.c:75
static bool atexit_callback_setup
Definition: ipc.c:51
#define FATAL
Definition: elog.h:52
#define ereport(elevel, rest)
Definition: elog.h:122
int errmsg_internal(const char *fmt,...)
Definition: elog.c:827
static int before_shmem_exit_index
Definition: ipc.c:83
Datum arg
Definition: ipc.c:76
void * arg
static struct ONEXIT before_shmem_exit_list[MAX_ON_EXITS]
Definition: ipc.c:81
static void atexit_callback(void)
Definition: ipc.c:284

◆ cancel_before_shmem_exit()

void cancel_before_shmem_exit ( pg_on_exit_callback  function,
Datum  arg 
)

Definition at line 384 of file ipc.c.

References before_shmem_exit_index, and before_shmem_exit_list.

Referenced by pg_stop_backup_v2().

385 {
386  if (before_shmem_exit_index > 0 &&
388  == function &&
391 }
static int before_shmem_exit_index
Definition: ipc.c:83
void * arg
static struct ONEXIT before_shmem_exit_list[MAX_ON_EXITS]
Definition: ipc.c:81

◆ on_exit_reset()

void on_exit_reset ( void  )

Definition at line 403 of file ipc.c.

References before_shmem_exit_index, on_proc_exit_index, on_shmem_exit_index, and reset_on_dsm_detach().

Referenced by bg_quickdie(), bgworker_quickdie(), chkpt_quickdie(), InitPostmasterChild(), quickdie(), startupproc_quickdie(), wal_quickdie(), and WalRcvQuickDieHandler().

404 {
407  on_proc_exit_index = 0;
409 }
void reset_on_dsm_detach(void)
Definition: dsm.c:1062
static int on_shmem_exit_index
Definition: ipc.c:83
static int on_proc_exit_index
Definition: ipc.c:83
static int before_shmem_exit_index
Definition: ipc.c:83

◆ on_proc_exit()

void on_proc_exit ( pg_on_exit_callback  function,
Datum  arg 
)

Definition at line 299 of file ipc.c.

References ONEXIT::arg, atexit_callback(), atexit_callback_setup, ereport, errcode(), errmsg_internal(), FATAL, ONEXIT::function, MAX_ON_EXITS, on_proc_exit_index, and on_proc_exit_list.

Referenced by CreateLockFile(), InitCatCache(), InitFileAccess(), PostgresMain(), PostmasterMain(), pq_init(), select_perl_context(), sepgsql_avc_init(), and smgrinit().

300 {
302  ereport(FATAL,
303  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
304  errmsg_internal("out of on_proc_exit slots")));
305 
308 
310 
312  {
313  atexit(atexit_callback);
314  atexit_callback_setup = true;
315  }
316 }
static struct ONEXIT on_proc_exit_list[MAX_ON_EXITS]
Definition: ipc.c:79
#define MAX_ON_EXITS
Definition: ipc.c:71
int errcode(int sqlerrcode)
Definition: elog.c:575
pg_on_exit_callback function
Definition: ipc.c:75
static bool atexit_callback_setup
Definition: ipc.c:51
#define FATAL
Definition: elog.h:52
#define ereport(elevel, rest)
Definition: elog.h:122
static int on_proc_exit_index
Definition: ipc.c:83
int errmsg_internal(const char *fmt,...)
Definition: elog.c:827
Datum arg
Definition: ipc.c:76
void * arg
static void atexit_callback(void)
Definition: ipc.c:284

◆ on_shmem_exit()

void on_shmem_exit ( pg_on_exit_callback  function,
Datum  arg 
)

Definition at line 355 of file ipc.c.

References ONEXIT::arg, atexit_callback(), atexit_callback_setup, ereport, errcode(), errmsg_internal(), FATAL, ONEXIT::function, MAX_ON_EXITS, on_shmem_exit_index, and on_shmem_exit_list.

Referenced by autoprewarm_main(), AutoVacWorkerMain(), dsm_postmaster_startup(), InitAuxiliaryProcess(), InitBufferPoolBackend(), InitPostgres(), InitProcess(), InitProcessPhase2(), InitWalSenderSlot(), InternalIpcMemoryCreate(), ParallelWorkerMain(), PGReserveSemaphores(), PGSharedMemoryCreate(), pgss_shmem_startup(), pgstat_initialize(), ProcSignalInit(), replorigin_session_setup(), SharedInvalBackendInit(), and WalReceiverMain().

356 {
358  ereport(FATAL,
359  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
360  errmsg_internal("out of on_shmem_exit slots")));
361 
364 
366 
368  {
369  atexit(atexit_callback);
370  atexit_callback_setup = true;
371  }
372 }
#define MAX_ON_EXITS
Definition: ipc.c:71
int errcode(int sqlerrcode)
Definition: elog.c:575
static int on_shmem_exit_index
Definition: ipc.c:83
pg_on_exit_callback function
Definition: ipc.c:75
static bool atexit_callback_setup
Definition: ipc.c:51
#define FATAL
Definition: elog.h:52
#define ereport(elevel, rest)
Definition: elog.h:122
static struct ONEXIT on_shmem_exit_list[MAX_ON_EXITS]
Definition: ipc.c:80
int errmsg_internal(const char *fmt,...)
Definition: elog.c:827
Datum arg
Definition: ipc.c:76
void * arg
static void atexit_callback(void)
Definition: ipc.c:284

◆ proc_exit()

void proc_exit ( int  code)

Definition at line 104 of file ipc.c.

References DEBUG3, elog, IsAutoVacuumWorkerProcess(), mkdir, proc_exit_prepare(), S_IRWXG, S_IRWXO, S_IRWXU, and snprintf().

Referenced by ApplyLauncherMain(), ApplyWorkerMain(), auth_failed(), autoprewarm_main(), AutoVacLauncherMain(), AutoVacWorkerMain(), AuxiliaryProcessMain(), BackendInitialize(), BackgroundWriterMain(), BootstrapModeMain(), CheckerModeMain(), CheckpointerMain(), copy_read_data(), errfinish(), ExitPostmaster(), HandleStartupProcInterrupts(), initialize_worker_spi(), logicalrep_worker_stop(), LogicalRepApplyLoop(), maybe_reread_subscription(), pg_attribute_noreturn(), pgstat_bestart(), PostgresMain(), PreRestoreCommand(), ProcessInterrupts(), ProcessRepliesIfAny(), ProcessStandbyMessage(), RestoreArchivedFile(), StartBackgroundWorker(), StartLogicalReplication(), StartReplication(), startup_die(), StartupPacketTimeoutHandler(), StartupProcessMain(), StartupProcShutdownHandler(), StartupXLOG(), SysLoggerMain(), test_shm_mq_main(), wait_for_relation_state_change(), wait_for_worker_state_change(), WaitForParallelWorkersToAttach(), WaitForReplicationWorkerAttach(), WalRcvWaitForStartPosition(), WalReceiverMain(), WalSndDone(), WalSndErrorCleanup(), and WalWriterMain().

105 {
106  /* Clean up everything that must be cleaned up */
107  proc_exit_prepare(code);
108 
109 #ifdef PROFILE_PID_DIR
110  {
111  /*
112  * If we are profiling ourself then gprof's mcleanup() is about to
113  * write out a profile to ./gmon.out. Since mcleanup() always uses a
114  * fixed file name, each backend will overwrite earlier profiles. To
115  * fix that, we create a separate subdirectory for each backend
116  * (./gprof/pid) and 'cd' to that subdirectory before we exit() - that
117  * forces mcleanup() to write each profile into its own directory. We
118  * end up with something like: $PGDATA/gprof/8829/gmon.out
119  * $PGDATA/gprof/8845/gmon.out ...
120  *
121  * To avoid undesirable disk space bloat, autovacuum workers are
122  * discriminated against: all their gmon.out files go into the same
123  * subdirectory. Without this, an installation that is "just sitting
124  * there" nonetheless eats megabytes of disk space every few seconds.
125  *
126  * Note that we do this here instead of in an on_proc_exit() callback
127  * because we want to ensure that this code executes last - we don't
128  * want to interfere with any other on_proc_exit() callback. For the
129  * same reason, we do not include it in proc_exit_prepare ... so if
130  * you are exiting in the "wrong way" you won't drop your profile in a
131  * nice place.
132  */
133  char gprofDirName[32];
134 
136  snprintf(gprofDirName, 32, "gprof/avworker");
137  else
138  snprintf(gprofDirName, 32, "gprof/%d", (int) getpid());
139 
140  mkdir("gprof", S_IRWXU | S_IRWXG | S_IRWXO);
141  mkdir(gprofDirName, S_IRWXU | S_IRWXG | S_IRWXO);
142  chdir(gprofDirName);
143  }
144 #endif
145 
146  elog(DEBUG3, "exit(%d)", code);
147 
148  exit(code);
149 }
#define DEBUG3
Definition: elog.h:23
static void proc_exit_prepare(int code)
Definition: ipc.c:157
int snprintf(char *str, size_t count, const char *fmt,...) pg_attribute_printf(3
#define S_IRWXG
Definition: win32_port.h:292
bool IsAutoVacuumWorkerProcess(void)
Definition: autovacuum.c:3255
#define S_IRWXU
Definition: win32_port.h:280
#define elog
Definition: elog.h:219
#define mkdir(a, b)
Definition: win32_port.h:58
#define S_IRWXO
Definition: win32_port.h:304

◆ proc_exit_prepare()

static void proc_exit_prepare ( int  code)
static

Definition at line 157 of file ipc.c.

References ONEXIT::arg, CritSectionCount, DEBUG3, debug_query_string, elog, error_context_stack, ONEXIT::function, InterruptHoldoffCount, InterruptPending, on_proc_exit_index, on_proc_exit_list, proc_exit_inprogress, ProcDiePending, QueryCancelPending, and shmem_exit().

Referenced by atexit_callback(), and proc_exit().

158 {
159  /*
160  * Once we set this flag, we are committed to exit. Any ereport() will
161  * NOT send control back to the main loop, but right back here.
162  */
163  proc_exit_inprogress = true;
164 
165  /*
166  * Forget any pending cancel or die requests; we're doing our best to
167  * close up shop already. Note that the signal handlers will not set
168  * these flags again, now that proc_exit_inprogress is set.
169  */
170  InterruptPending = false;
171  ProcDiePending = false;
172  QueryCancelPending = false;
174  CritSectionCount = 0;
175 
176  /*
177  * Also clear the error context stack, to prevent error callbacks from
178  * being invoked by any elog/ereport calls made during proc_exit. Whatever
179  * context they might want to offer is probably not relevant, and in any
180  * case they are likely to fail outright after we've done things like
181  * aborting any open transaction. (In normal exit scenarios the context
182  * stack should be empty anyway, but it might not be in the case of
183  * elog(FATAL) for example.)
184  */
185  error_context_stack = NULL;
186  /* For the same reason, reset debug_query_string before it's clobbered */
187  debug_query_string = NULL;
188 
189  /* do our shared memory exits first */
190  shmem_exit(code);
191 
192  elog(DEBUG3, "proc_exit(%d): %d callbacks to make",
193  code, on_proc_exit_index);
194 
195  /*
196  * call all the registered callbacks.
197  *
198  * Note that since we decrement on_proc_exit_index each time, if a
199  * callback calls ereport(ERROR) or ereport(FATAL) then it won't be
200  * invoked again when control comes back here (nor will the
201  * previously-completed callbacks). So, an infinite loop should not be
202  * possible.
203  */
204  while (--on_proc_exit_index >= 0)
207 
208  on_proc_exit_index = 0;
209 }
volatile uint32 InterruptHoldoffCount
Definition: globals.c:35
static struct ONEXIT on_proc_exit_list[MAX_ON_EXITS]
Definition: ipc.c:79
#define DEBUG3
Definition: elog.h:23
void shmem_exit(int code)
Definition: ipc.c:220
volatile bool QueryCancelPending
Definition: globals.c:30
ErrorContextCallback * error_context_stack
Definition: elog.c:88
pg_on_exit_callback function
Definition: ipc.c:75
volatile uint32 CritSectionCount
Definition: globals.c:37
const char * debug_query_string
Definition: postgres.c:85
static int on_proc_exit_index
Definition: ipc.c:83
volatile bool InterruptPending
Definition: globals.c:29
bool proc_exit_inprogress
Definition: ipc.c:40
volatile bool ProcDiePending
Definition: globals.c:31
void * arg
#define elog
Definition: elog.h:219

◆ shmem_exit()

void shmem_exit ( int  code)

Definition at line 220 of file ipc.c.

References ONEXIT::arg, before_shmem_exit_index, before_shmem_exit_list, DEBUG3, dsm_backend_shutdown(), elog, ONEXIT::function, on_shmem_exit_index, on_shmem_exit_list, and shmem_exit_inprogress.

Referenced by PostmasterStateMachine(), and proc_exit_prepare().

221 {
222  shmem_exit_inprogress = true;
223 
224  /*
225  * Call before_shmem_exit callbacks.
226  *
227  * These should be things that need most of the system to still be up and
228  * working, such as cleanup of temp relations, which requires catalog
229  * access; or things that need to be completed because later cleanup steps
230  * depend on them, such as releasing lwlocks.
231  */
232  elog(DEBUG3, "shmem_exit(%d): %d before_shmem_exit callbacks to make",
234  while (--before_shmem_exit_index >= 0)
238 
239  /*
240  * Call dynamic shared memory callbacks.
241  *
242  * These serve the same purpose as late callbacks, but for dynamic shared
243  * memory segments rather than the main shared memory segment.
244  * dsm_backend_shutdown() has the same kind of progressive logic we use
245  * for the main shared memory segment; namely, it unregisters each
246  * callback before invoking it, so that we don't get stuck in an infinite
247  * loop if one of those callbacks itself throws an ERROR or FATAL.
248  *
249  * Note that explicitly calling this function here is quite different from
250  * registering it as an on_shmem_exit callback for precisely this reason:
251  * if one dynamic shared memory callback errors out, the remaining
252  * callbacks will still be invoked. Thus, hard-coding this call puts it
253  * equal footing with callbacks for the main shared memory segment.
254  */
256 
257  /*
258  * Call on_shmem_exit callbacks.
259  *
260  * These are generally releasing low-level shared memory resources. In
261  * some cases, this is a backstop against the possibility that the early
262  * callbacks might themselves fail, leading to re-entry to this routine;
263  * in other cases, it's cleanup that only happens at process exit.
264  */
265  elog(DEBUG3, "shmem_exit(%d): %d on_shmem_exit callbacks to make",
266  code, on_shmem_exit_index);
267  while (--on_shmem_exit_index >= 0)
271 }
#define DEBUG3
Definition: elog.h:23
static int on_shmem_exit_index
Definition: ipc.c:83
pg_on_exit_callback function
Definition: ipc.c:75
void dsm_backend_shutdown(void)
Definition: dsm.c:635
static struct ONEXIT on_shmem_exit_list[MAX_ON_EXITS]
Definition: ipc.c:80
static int before_shmem_exit_index
Definition: ipc.c:83
bool shmem_exit_inprogress
Definition: ipc.c:45
void * arg
static struct ONEXIT before_shmem_exit_list[MAX_ON_EXITS]
Definition: ipc.c:81
#define elog
Definition: elog.h:219

Variable Documentation

◆ atexit_callback_setup

bool atexit_callback_setup = false
static

Definition at line 51 of file ipc.c.

Referenced by before_shmem_exit(), on_proc_exit(), and on_shmem_exit().

◆ before_shmem_exit_index

int before_shmem_exit_index
static

Definition at line 83 of file ipc.c.

Referenced by before_shmem_exit(), cancel_before_shmem_exit(), on_exit_reset(), and shmem_exit().

◆ before_shmem_exit_list

struct ONEXIT before_shmem_exit_list[MAX_ON_EXITS]
static

Definition at line 81 of file ipc.c.

Referenced by before_shmem_exit(), cancel_before_shmem_exit(), and shmem_exit().

◆ on_proc_exit_index

int on_proc_exit_index
static

Definition at line 83 of file ipc.c.

Referenced by on_exit_reset(), on_proc_exit(), and proc_exit_prepare().

◆ on_proc_exit_list

struct ONEXIT on_proc_exit_list[MAX_ON_EXITS]
static

Definition at line 79 of file ipc.c.

Referenced by on_proc_exit(), and proc_exit_prepare().

◆ on_shmem_exit_index

int on_shmem_exit_index
static

Definition at line 83 of file ipc.c.

Referenced by on_exit_reset(), on_shmem_exit(), and shmem_exit().

◆ on_shmem_exit_list

struct ONEXIT on_shmem_exit_list[MAX_ON_EXITS]
static

Definition at line 80 of file ipc.c.

Referenced by on_shmem_exit(), and shmem_exit().

◆ proc_exit_inprogress

◆ shmem_exit_inprogress

bool shmem_exit_inprogress = false

Definition at line 45 of file ipc.c.

Referenced by AtAbort_Portals(), and shmem_exit().