On ons, 2012-01-18 at 21:21 +0200, Peter Eisentraut wrote:
> On lör, 2012-01-07 at 16:41 -0500, Tom Lane wrote:
> > Peter Eisentraut <[email protected]> writes:
> > > I suggest that we change PostgresMain(), PostmasterMain(), BackendRun(),
> > > WalSenderMain(), and WalSndLoop() to return void as well.
> >
> > I agree this code is not very consistent or useful, but one question:
> > what should the callers do if one of these functions *does* return?
>
> I was thinking of a two-pronged approach: First, add
> __attribute__((noreturn)) to the functions. This will cause a suitable
> compiler to verify on a source-code level that nothing actually returns
> from the function. And second, at the call site, put an abort(); /*
> not reached */. Together, this will make the code cleaner and more
> consistent, and will also help the compiler out a bit about the control
> flow.
Patch for 9.3 attached.
diff --git a/src/backend/main/main.c b/src/backend/main/main.c
index c7d48e9..33c5a0a 100644
--- a/src/backend/main/main.c
+++ b/src/backend/main/main.c
@@ -173,7 +173,7 @@
#ifdef EXEC_BACKEND
if (argc > 1 && strncmp(argv[1], "--fork", 6) == 0)
- exit(SubPostmasterMain(argc, argv));
+ SubPostmasterMain(argc, argv); /* does not return */
#endif
#ifdef WIN32
@@ -189,14 +189,13 @@
if (argc > 1 && strcmp(argv[1], "--boot") == 0)
AuxiliaryProcessMain(argc, argv); /* does not return */
-
- if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
- exit(GucInfoMain());
-
- if (argc > 1 && strcmp(argv[1], "--single") == 0)
- exit(PostgresMain(argc, argv, get_current_username(progname)));
-
- exit(PostmasterMain(argc, argv));
+ else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)
+ GucInfoMain(); /* does not return */
+ else if (argc > 1 && strcmp(argv[1], "--single") == 0)
+ PostgresMain(argc, argv, get_current_username(progname)); /* does not return */
+ else
+ PostmasterMain(argc, argv); /* does not return */
+ abort(); /* should not get here */
}
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index eeea933..0f8af3a 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -343,8 +343,8 @@ static void LogChildExit(int lev, const char *procname,
int pid, int exitstatus);
static void PostmasterStateMachine(void);
static void BackendInitialize(Port *port);
-static int BackendRun(Port *port);
-static void ExitPostmaster(int status);
+static void BackendRun(Port *port) __attribute__((noreturn));
+static void ExitPostmaster(int status) __attribute__((noreturn));
static int ServerLoop(void);
static int BackendStartup(Port *port);
static int ProcessStartupPacket(Port *port, bool SSLdone);
@@ -491,7 +491,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
/*
* Postmaster main entry point
*/
-int
+void
PostmasterMain(int argc, char *argv[])
{
int opt;
@@ -1125,7 +1125,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
*/
ExitPostmaster(status != STATUS_OK);
- return 0; /* not reached */
+ abort(); /* not reached */
}
@@ -3295,7 +3295,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
BackendInitialize(port);
/* And run the backend */
- proc_exit(BackendRun(port));
+ BackendRun(port);
}
#endif /* EXEC_BACKEND */
@@ -3539,7 +3539,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
* Shouldn't return at all.
* If PostgresMain() fails, return status.
*/
-static int
+static void
BackendRun(Port *port)
{
char **av;
@@ -3610,7 +3610,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
*/
MemoryContextSwitchTo(TopMemoryContext);
- return (PostgresMain(ac, av, port->user_name));
+ PostgresMain(ac, av, port->user_name);
}
@@ -3960,7 +3960,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
* have been inherited by fork() on Unix. Remaining arguments go to the
* subprocess FooMain() routine.
*/
-int
+void
SubPostmasterMain(int argc, char *argv[])
{
Port port;
@@ -4195,7 +4195,7 @@ static bool save_backend_variables(BackendParameters *param, Port *port,
proc_exit(0);
}
- return 1; /* shouldn't get here */
+ abort(); /* shouldn't get here */
}
#endif /* EXEC_BACKEND */
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 45a3b2e..a9a8689 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -121,7 +121,7 @@
/* Prototypes for private functions */
static bool HandleReplicationCommand(const char *cmd_string);
-static int WalSndLoop(void);
+static void WalSndLoop(void) __attribute__((noreturn));
static void InitWalSnd(void);
static void WalSndHandshake(void);
static void WalSndKill(int code, Datum arg);
@@ -136,7 +136,7 @@
/* Main entry point for walsender process */
-int
+void
WalSenderMain(void)
{
MemoryContext walsnd_context;
@@ -193,7 +193,7 @@
SyncRepInitConfig();
/* Main loop of walsender */
- return WalSndLoop();
+ WalSndLoop();
}
/*
@@ -708,7 +708,7 @@
}
/* Main loop of walsender process */
-static int
+static void
WalSndLoop(void)
{
char *output_message;
@@ -884,7 +884,7 @@
whereToSendOutput = DestNone;
proc_exit(0);
- return 1; /* keep the compiler quiet */
+ abort(); /* keep the compiler quiet */
}
/* Initialize a per-walsender data structure for this walsender process */
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 51b6df5..9a5438f 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3507,7 +3507,7 @@
* for the session.
* ----------------------------------------------------------------
*/
-int
+void
PostgresMain(int argc, char *argv[], const char *username)
{
const char *dbname;
@@ -3721,7 +3721,10 @@
/* If this is a WAL sender process, we're done with initialization. */
if (am_walsender)
- proc_exit(WalSenderMain());
+ {
+ WalSenderMain(); /* does not return */
+ abort();
+ }
/*
* process any libraries that should be preloaded at backend start (this
@@ -4199,7 +4202,7 @@
/* can't get here because the above loop never exits */
Assert(false);
- return 1; /* keep compiler quiet */
+ abort(); /* keep compiler quiet */
}
diff --git a/src/backend/utils/misc/help_config.c b/src/backend/utils/misc/help_config.c
index 5f772f9..386ec98 100644
--- a/src/backend/utils/misc/help_config.c
+++ b/src/backend/utils/misc/help_config.c
@@ -43,7 +43,7 @@
static bool displayStruct(mixedStruct *structToDisplay);
-int
+void
GucInfoMain(void)
{
struct config_generic **guc_vars;
@@ -64,7 +64,7 @@
printMixedStruct(var);
}
- return 0;
+ exit(0);
}
diff --git a/src/include/bootstrap/bootstrap.h b/src/include/bootstrap/bootstrap.h
index e966a73..b31bca9 100644
--- a/src/include/bootstrap/bootstrap.h
+++ b/src/include/bootstrap/bootstrap.h
@@ -40,7 +40,7 @@ extern Form_pg_attribute attrtypes[MAXATTR];
extern int numattr;
-extern void AuxiliaryProcessMain(int argc, char *argv[]);
+extern void AuxiliaryProcessMain(int argc, char *argv[]) __attribute__((noreturn));
extern void err_out(void);
diff --git a/src/include/postmaster/bgwriter.h b/src/include/postmaster/bgwriter.h
index f46d4ad..996065c 100644
--- a/src/include/postmaster/bgwriter.h
+++ b/src/include/postmaster/bgwriter.h
@@ -25,8 +25,8 @@ extern int CheckPointTimeout;
extern int CheckPointWarning;
extern double CheckPointCompletionTarget;
-extern void BackgroundWriterMain(void);
-extern void CheckpointerMain(void);
+extern void BackgroundWriterMain(void) __attribute__((noreturn));
+extern void CheckpointerMain(void) __attribute__((noreturn));
extern void RequestCheckpoint(int flags);
extern void CheckpointWriteDelay(int flags, double progress);
diff --git a/src/include/postmaster/postmaster.h b/src/include/postmaster/postmaster.h
index 683ce3c..72c1423 100644
--- a/src/include/postmaster/postmaster.h
+++ b/src/include/postmaster/postmaster.h
@@ -46,7 +46,7 @@ extern int postmaster_alive_fds[2];
extern const char *progname;
-extern int PostmasterMain(int argc, char *argv[]);
+extern void PostmasterMain(int argc, char *argv[]) __attribute__((noreturn));
extern void ClosePostmasterPorts(bool am_syslogger);
extern int MaxLivePostmasterChildren(void);
diff --git a/src/include/postmaster/startup.h b/src/include/postmaster/startup.h
index 3ec6950..54400b5 100644
--- a/src/include/postmaster/startup.h
+++ b/src/include/postmaster/startup.h
@@ -13,7 +13,7 @@
#define _STARTUP_H
extern void HandleStartupProcInterrupts(void);
-extern void StartupProcessMain(void);
+extern void StartupProcessMain(void) __attribute__((noreturn));
extern void PreRestoreCommand(void);
extern void PostRestoreCommand(void);
extern bool IsPromoteTriggered(void);
diff --git a/src/include/postmaster/walwriter.h b/src/include/postmaster/walwriter.h
index 41c539a..922142a 100644
--- a/src/include/postmaster/walwriter.h
+++ b/src/include/postmaster/walwriter.h
@@ -15,6 +15,6 @@
/* GUC options */
extern int WalWriterDelay;
-extern void WalWriterMain(void);
+extern void WalWriterMain(void) __attribute__((noreturn));
#endif /* _WALWRITER_H */
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index d21ec94..31449d2 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -109,7 +109,7 @@ typedef void (*walrcv_disconnect_type) (void);
extern PGDLLIMPORT walrcv_disconnect_type walrcv_disconnect;
/* prototypes for functions in walreceiver.c */
-extern void WalReceiverMain(void);
+extern void WalReceiverMain(void) __attribute__((noreturn));
/* prototypes for functions in walreceiverfuncs.c */
extern Size WalRcvShmemSize(void);
diff --git a/src/include/replication/walsender.h b/src/include/replication/walsender.h
index 128d2db..38b6e8e 100644
--- a/src/include/replication/walsender.h
+++ b/src/include/replication/walsender.h
@@ -26,7 +26,7 @@ extern volatile sig_atomic_t walsender_ready_to_stop;
extern int max_wal_senders;
extern int replication_timeout;
-extern int WalSenderMain(void);
+extern void WalSenderMain(void) __attribute__((noreturn));
extern void WalSndSignals(void);
extern Size WalSndShmemSize(void);
extern void WalSndShmemInit(void);
diff --git a/src/include/storage/ipc.h b/src/include/storage/ipc.h
index 16025c3..3bc2e58 100644
--- a/src/include/storage/ipc.h
+++ b/src/include/storage/ipc.h
@@ -64,7 +64,7 @@ typedef void (*shmem_startup_hook_type) (void);
/* ipc.c */
extern bool proc_exit_inprogress;
-extern void proc_exit(int code);
+extern void proc_exit(int code) __attribute__((noreturn));
extern void shmem_exit(int code);
extern void on_proc_exit(pg_on_exit_callback function, Datum arg);
extern void on_shmem_exit(pg_on_exit_callback function, Datum arg);
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 964dd19..ccd2b89 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -61,7 +61,7 @@ extern bool check_max_stack_depth(int *newval, void **extra, GucSource source);
extern void assign_max_stack_depth(int newval, void *extra);
extern void die(SIGNAL_ARGS);
-extern void quickdie(SIGNAL_ARGS);
+extern void quickdie(SIGNAL_ARGS) __attribute__((noreturn));
extern void StatementCancelHandler(SIGNAL_ARGS);
extern void FloatExceptionHandler(SIGNAL_ARGS);
extern void RecoveryConflictInterrupt(ProcSignalReason reason); /* called from SIGUSR1
@@ -70,7 +70,7 @@ extern void prepare_for_client_read(void);
extern void client_read_ended(void);
extern const char *process_postgres_switches(int argc, char *argv[],
GucContext ctx);
-extern int PostgresMain(int argc, char *argv[], const char *username);
+extern void PostgresMain(int argc, char *argv[], const char *username) __attribute__((noreturn));
extern long get_stack_depth_rlimit(void);
extern void ResetUsage(void);
extern void ShowUsage(const char *title);
diff --git a/src/include/utils/help_config.h b/src/include/utils/help_config.h
index b569a4e..62d7e49 100644
--- a/src/include/utils/help_config.h
+++ b/src/include/utils/help_config.h
@@ -12,6 +12,6 @@
#ifndef HELP_CONFIG_H
#define HELP_CONFIG_H 1
-extern int GucInfoMain(void);
+extern void GucInfoMain(void) __attribute__((noreturn));
#endif
--
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