Function PostmasterMain

src/backend/postmaster/postmaster.c:703–1685

* Postmaster main entry point */

 * Postmaster main entry point
 */
void
PostmasterMain(int argc, char *argv[])
{
	int			opt;
	int			status;
	char	   *userDoption = NULL;
	bool		listen_addr_saved = false;
	int			i;
	char	   *output_config_variable = NULL;

	InitProcessGlobals();

	PostmasterPid = MyProcPid;

	IsPostmasterEnvironment = true;

	/*
	 * We should not be creating any files or directories before we check the
	 * data directory (see checkDataDir()), but just in case set the umask to
	 * the most restrictive (owner-only) permissions.
	 *
	 * checkDataDir() will reset the umask based on the data directory
	 * permissions.
	 */
	umask(PG_MODE_MASK_OWNER);

	/*
	 * Initialize random(3) so we don't get the same values in every run.
	 *
	 * Note: the seed is pretty predictable from externally-visible facts such
	 * as postmaster start time, so avoid using random() for security-critical
	 * random values during postmaster startup.  At the time of first
	 * connection, PostmasterRandom will select a hopefully-more-random seed.
	 */
	srandom((unsigned int) (MyProcPid ^ MyStartTime));

	/*
	 * By default, palloc() requests in the postmaster will be allocated in
	 * the PostmasterContext, which is space that can be recycled by backends.
	 * Allocated data that needs to be available to backends should be
	 * allocated in TopMemoryContext.
	 */
	PostmasterContext = AllocSetContextCreate(TopMemoryContext,
											  "Postmaster",
											  ALLOCSET_DEFAULT_SIZES);
	MemoryContextSwitchTo(PostmasterContext);

	/* Initialize paths to installation files */
	getInstallationPaths(argv[0]);

	/*
	 * Set up signal handlers for the postmaster process.
	 *
	 * In the postmaster, we use pqsignal_pm() rather than pqsignal() (which
	 * is used by all child processes and client processes).  That has a
	 * couple of special behaviors:
	 *
	 * 1. We tell sigaction() to block all signals for the duration of the