postgresql/src/backend/postmaster/postmaster.c

3663 lines
89 KiB
C

/*-------------------------------------------------------------------------
*
* postmaster.c
* This program acts as a clearing house for requests to the
* POSTGRES system. Frontend programs send a startup message
* to the Postmaster and the postmaster uses the info in the
* message to setup a backend process.
*
* The postmaster also manages system-wide operations such as
* startup, shutdown, and periodic checkpoints. The postmaster
* itself doesn't do those operations, mind you --- it just forks
* off a subprocess to do them at the right times. It also takes
* care of resetting the system if a backend crashes.
*
* The postmaster process creates the shared memory and semaphore
* pools during startup, but as a rule does not touch them itself.
* In particular, it is not a member of the PGPROC array of backends
* and so it cannot participate in lock-manager operations. Keeping
* the postmaster away from shared memory operations makes it simpler
* and more reliable. The postmaster is almost always able to recover
* from crashes of individual backends by resetting shared memory;
* if it did much with shared memory then it would be prone to crashing
* along with the backends.
*
* When a request message is received, we now fork() immediately.
* The child process performs authentication of the request, and
* then becomes a backend if successful. This allows the auth code
* to be written in a simple single-threaded style (as opposed to the
* crufty "poor man's multitasking" code that used to be needed).
* More importantly, it ensures that blockages in non-multithreaded
* libraries like SSL or PAM cannot cause denial of service to other
* clients.
*
*
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.393 2004/05/21 05:07:57 tgl Exp $
*
* NOTES
*
* Initialization:
* The Postmaster sets up a few shared memory data structures
* for the backends. It should at the very least initialize the
* lock manager.
*
* Synchronization:
* The Postmaster shares memory with the backends but should avoid
* touching shared memory, so as not to become stuck if a crashing
* backend screws up locks or shared memory. Likewise, the Postmaster
* should never block on messages from frontend clients.
*
* Garbage Collection:
* The Postmaster cleans up after backends if they have an emergency
* exit and/or core dump.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include <ctype.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <limits.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#ifdef USE_RENDEZVOUS
#include <DNSServiceDiscovery/DNSServiceDiscovery.h>
#endif
#include "catalog/pg_database.h"
#include "commands/async.h"
#include "lib/dllist.h"
#include "libpq/auth.h"
#include "libpq/crypt.h"
#include "libpq/libpq.h"
#include "libpq/pqcomm.h"
#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "nodes/nodes.h"
#include "pgtime.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/bufmgr.h"
#include "access/xlog.h"
#include "tcop/tcopprot.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/ps_status.h"
#include "bootstrap/bootstrap.h"
#include "pgstat.h"
#define INVALID_SOCK (-1)
#ifdef HAVE_SIGPROCMASK
sigset_t UnBlockSig,
BlockSig,
AuthBlockSig;
#else
int UnBlockSig,
BlockSig,
AuthBlockSig;
#endif
/*
* List of active backends (or child processes anyway; we don't actually
* know whether a given child has become a backend or is still in the
* authorization phase). This is used mainly to keep track of how many
* children we have and send them appropriate signals when necessary.
*/
typedef struct bkend
{
pid_t pid; /* process id of backend */
long cancel_key; /* cancel key for cancels for this backend */
} Backend;
static Dllist *BackendList;
#ifdef EXEC_BACKEND
#define NUM_BACKENDARRAY_ELEMS (2*MaxBackends)
static Backend *ShmemBackendArray;
#endif
/* The socket number we are listening for connections on */
int PostPortNumber;
char *UnixSocketDir;
char *ListenAddresses;
/*
* MaxBackends is the limit on the number of backends we can start.
* Note that a larger MaxBackends value will increase the size of the
* shared memory area as well as cause the postmaster to grab more
* kernel semaphores, even if you never actually use that many
* backends.
*/
int MaxBackends;
/*
* ReservedBackends is the number of backends reserved for superuser use.
* This number is taken out of the pool size given by MaxBackends so
* number of backend slots available to non-superusers is
* (MaxBackends - ReservedBackends). Note what this really means is
* "if there are <= ReservedBackends connections available, only superusers
* can make new connections" --- pre-existing superuser connections don't
* count against the limit.
*/
int ReservedBackends;
static const char *progname = NULL;
/* The socket(s) we're listening to. */
#define MAXLISTEN 10
static int ListenSocket[MAXLISTEN];
/* Used to reduce macros tests */
#ifdef EXEC_BACKEND
const bool ExecBackend = true;
#else
const bool ExecBackend = false;
#endif
/*
* Set by the -o option
*/
static char ExtraOptions[MAXPGPATH];
/*
* These globals control the behavior of the postmaster in case some
* backend dumps core. Normally, it kills all peers of the dead backend
* and reinitializes shared memory. By specifying -s or -n, we can have
* the postmaster stop (rather than kill) peers and not reinitialize
* shared data structures.
*/
static bool Reinit = true;
static int SendStop = false;
/* still more option variables */
bool EnableSSL = false;
bool SilentMode = false; /* silent mode (-S) */
int PreAuthDelay = 0;
int AuthenticationTimeout = 60;
int CheckPointTimeout = 300;
int CheckPointWarning = 30;
time_t LastSignalledCheckpoint = 0;
bool log_hostname; /* for ps display and logging */
bool Log_connections = false;
bool Db_user_namespace = false;
char *rendezvous_name;
/* list of library:init-function to be preloaded */
char *preload_libraries_string = NULL;
/* Startup/shutdown state */
static pid_t StartupPID = 0,
ShutdownPID = 0,
CheckPointPID = 0,
BgWriterPID = 0;
static time_t checkpointed = 0;
#define NoShutdown 0
#define SmartShutdown 1
#define FastShutdown 2
static int Shutdown = NoShutdown;
static bool FatalError = false; /* T if recovering from backend crash */
bool ClientAuthInProgress = false; /* T during new-client
* authentication */
/*
* State for assigning random salts and cancel keys.
* Also, the global MyCancelKey passes the cancel key assigned to a given
* backend from the postmaster to that backend (via fork).
*/
static unsigned int random_seed = 0;
static int debug_flag = 0;
extern char *optarg;
extern int optind,
opterr;
#ifdef HAVE_INT_OPTRESET
extern int optreset;
#endif
/*
* postmaster.c - function prototypes
*/
static void pmdaemonize(int argc, char *argv[]);
static Port *ConnCreate(int serverFd);
static void ConnFree(Port *port);
static void reset_shared(unsigned short port);
static void SIGHUP_handler(SIGNAL_ARGS);
static void pmdie(SIGNAL_ARGS);
static void reaper(SIGNAL_ARGS);
static void sigusr1_handler(SIGNAL_ARGS);
static void dummy_handler(SIGNAL_ARGS);
static void CleanupProc(int pid, int exitstatus);
static void LogChildExit(int lev, const char *procname,
int pid, int exitstatus);
static void BackendInit(Port *port);
static int BackendRun(Port *port);
static void ExitPostmaster(int status);
static void usage(const char *);
static int ServerLoop(void);
static int BackendStartup(Port *port);
static int ProcessStartupPacket(Port *port, bool SSLdone);
static void processCancelRequest(Port *port, void *pkt);
static int initMasks(fd_set *rmask);
static void report_fork_failure_to_client(Port *port, int errnum);
static enum CAC_state canAcceptConnections(void);
static long PostmasterRandom(void);
static void RandomSalt(char *cryptSalt, char *md5Salt);
static void SignalChildren(int signal);
static int CountChildren(void);
static bool CreateOptsFile(int argc, char *argv[], char *fullprogname);
NON_EXEC_STATIC void SSDataBaseInit(int xlop);
static pid_t SSDataBase(int xlop);
static void
postmaster_error(const char *fmt,...)
/* This lets gcc check the format string for consistency. */
__attribute__((format(printf, 1, 2)));
#ifdef EXEC_BACKEND
#ifdef WIN32
pid_t win32_forkexec(const char* path, char *argv[]);
static void win32_AddChild(pid_t pid, HANDLE handle);
static void win32_RemoveChild(pid_t pid);
static pid_t win32_waitpid(int *exitstatus);
static DWORD WINAPI win32_sigchld_waiter(LPVOID param);
static pid_t *win32_childPIDArray;
static HANDLE *win32_childHNDArray;
static unsigned long win32_numChildren = 0;
#endif
static pid_t Backend_forkexec(Port *port);
static unsigned long tmpBackendFileNum = 0;
void read_backend_variables(unsigned long id, Port *port);
static bool write_backend_variables(Port *port);
static void ShmemBackendArrayAdd(Backend *bn);
static void ShmemBackendArrayRemove(pid_t pid);
#endif
#define StartupDataBase() SSDataBase(BS_XLOG_STARTUP)
#define CheckPointDataBase() SSDataBase(BS_XLOG_CHECKPOINT)
#define StartBackgroundWriter() SSDataBase(BS_XLOG_BGWRITER)
#define ShutdownDataBase() SSDataBase(BS_XLOG_SHUTDOWN)
static void
checkDataDir(const char *checkdir)
{
char path[MAXPGPATH];
FILE *fp;
struct stat stat_buf;
if (checkdir == NULL)
{
fprintf(stderr,
gettext("%s does not know where to find the database system data.\n"
"You must specify the directory that contains the database system\n"
"either by specifying the -D invocation option or by setting the\n"
"PGDATA environment variable.\n"),
progname);
ExitPostmaster(2);
}
if (stat(checkdir, &stat_buf) == -1)
{
if (errno == ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("data directory \"%s\" does not exist",
checkdir)));
else
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not read permissions of directory \"%s\": %m",
checkdir)));
}
/*
* Check if the directory has group or world access. If so, reject.
*
* XXX temporarily suppress check when on Windows, because there may not
* be proper support for Unix-y file permissions. Need to think of a
* reasonable check to apply on Windows.
*/
#if !defined(__CYGWIN__) && !defined(WIN32)
if (stat_buf.st_mode & (S_IRWXG | S_IRWXO))
ereport(FATAL,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("data directory \"%s\" has group or world access",
checkdir),
errdetail("Permissions should be u=rwx (0700).")));
#endif
/* Look for PG_VERSION before looking for pg_control */
ValidatePgVersion(checkdir);
snprintf(path, sizeof(path), "%s/global/pg_control", checkdir);
fp = AllocateFile(path, PG_BINARY_R);
if (fp == NULL)
{
fprintf(stderr,
gettext("%s: could not find the database system\n"
"Expected to find it in the directory \"%s\",\n"
"but could not open file \"%s\": %s\n"),
progname, checkdir, path, strerror(errno));
ExitPostmaster(2);
}
FreeFile(fp);
}
#ifdef USE_RENDEZVOUS
/* reg_reply -- empty callback function for DNSServiceRegistrationCreate() */
static void
reg_reply(DNSServiceRegistrationReplyErrorType errorCode, void *context)
{
}
#endif
int
PostmasterMain(int argc, char *argv[])
{
int opt;
int status;
char original_extraoptions[MAXPGPATH];
char *potential_DataDir = NULL;
int i;
*original_extraoptions = '\0';
progname = get_progname(argv[0]);
IsPostmasterEnvironment = true;
/*
* Catch standard options before doing much else. This even works on
* systems without getopt_long.
*/
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
usage(progname);
ExitPostmaster(0);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
puts("postmaster (PostgreSQL) " PG_VERSION);
ExitPostmaster(0);
}
}
/*
* for security, no dir or file created can be group or other
* accessible
*/
umask((mode_t) 0077);
MyProcPid = PostmasterPid = getpid();
/*
* Fire up essential subsystems: memory management
*/
MemoryContextInit();
/*
* 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_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
MemoryContextSwitchTo(PostmasterContext);
IgnoreSystemIndexes(false);
if (find_my_exec(argv[0], my_exec_path) < 0)
elog(FATAL,
gettext("%s: could not locate my own executable path"),
argv[0]);
get_pkglib_path(my_exec_path, pkglib_path);
/*
* Options setup
*/
InitializeGUCOptions();
potential_DataDir = getenv("PGDATA"); /* default value */
opterr = 1;
while ((opt = getopt(argc, argv, "A:a:B:b:c:D:d:Fh:ik:lm:MN:no:p:Ss-:")) != -1)
{
switch (opt)
{
case 'A':
#ifdef USE_ASSERT_CHECKING
SetConfigOption("debug_assertions", optarg, PGC_POSTMASTER, PGC_S_ARGV);
#else
postmaster_error("assert checking is not compiled in");
#endif
break;
case 'a':
/* Can no longer set authentication method. */
break;
case 'B':
SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'b':
/* Can no longer set the backend executable file to use. */
break;
case 'D':
potential_DataDir = optarg;
break;
case 'd':
{
/* Turn on debugging for the postmaster. */
char *debugstr = palloc(strlen("debug") + strlen(optarg) + 1);
sprintf(debugstr, "debug%s", optarg);
SetConfigOption("log_min_messages", debugstr,
PGC_POSTMASTER, PGC_S_ARGV);
pfree(debugstr);
debug_flag = atoi(optarg);
break;
}
case 'F':
SetConfigOption("fsync", "false", PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'h':
SetConfigOption("listen_addresses", optarg, PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'i':
SetConfigOption("listen_addresses", "*", PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'k':
SetConfigOption("unix_socket_directory", optarg, PGC_POSTMASTER, PGC_S_ARGV);
break;
#ifdef USE_SSL
case 'l':
SetConfigOption("ssl", "true", PGC_POSTMASTER, PGC_S_ARGV);
break;
#endif
case 'm':
/* Multiplexed backends no longer supported. */
break;
case 'M':
/*
* ignore this flag. This may be passed in because the
* program was run as 'postgres -M' instead of
* 'postmaster'
*/
break;
case 'N':
/* The max number of backends to start. */
SetConfigOption("max_connections", optarg, PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'n':
/* Don't reinit shared mem after abnormal exit */
Reinit = false;
break;
case 'o':
/*
* Other options to pass to the backend on the command
* line -- useful only for debugging.
*/
strcat(ExtraOptions, " ");
strcat(ExtraOptions, optarg);
strcpy(original_extraoptions, optarg);
break;
case 'p':
SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV);
break;
case 'S':
/*
* Start in 'S'ilent mode (disassociate from controlling
* tty). You may also think of this as 'S'ysV mode since
* it's most badly needed on SysV-derived systems like
* SVR4 and HP-UX.
*/
SetConfigOption("silent_mode", "true", PGC_POSTMASTER, PGC_S_ARGV);
break;
case 's':
/*
* In the event that some backend dumps core, send
* SIGSTOP, rather than SIGQUIT, to all its peers. This
* lets the wily post_hacker collect core dumps from
* everyone.
*/
SendStop = true;
break;
case 'c':
case '-':
{
char *name,
*value;
ParseLongOption(optarg, &name, &value);
if (!value)
{
if (opt == '-')
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("--%s requires a value",
optarg)));
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("-c %s requires a value",
optarg)));
}
SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
free(name);
if (value)
free(value);
break;
}
default:
fprintf(stderr,
gettext("Try \"%s --help\" for more information.\n"),
progname);
ExitPostmaster(1);
}
}
/*
* Postmaster accepts no non-option switch arguments.
*/
if (optind < argc)
{
postmaster_error("invalid argument: \"%s\"", argv[optind]);
fprintf(stderr,
gettext("Try \"%s --help\" for more information.\n"),
progname);
ExitPostmaster(1);
}
/*
* Now we can set the data directory, and then read postgresql.conf.
*/
checkDataDir(potential_DataDir); /* issues error messages */
SetDataDir(potential_DataDir);
ProcessConfigFile(PGC_POSTMASTER);
/* If timezone is not set, determine what the OS uses */
pg_timezone_initialize();
#ifdef EXEC_BACKEND
write_nondefault_variables(PGC_POSTMASTER);
#endif
/*
* Check for invalid combinations of GUC settings.
*/
if (NBuffers < 2 * MaxBackends || NBuffers < 16)
{
/*
* Do not accept -B so small that backends are likely to starve
* for lack of buffers. The specific choices here are somewhat
* arbitrary.
*/
postmaster_error("the number of buffers (-B) must be at least twice the number of allowed connections (-N) and at least 16");
ExitPostmaster(1);
}
if (ReservedBackends >= MaxBackends)
{
postmaster_error("superuser_reserved_connections must be less than max_connections");
ExitPostmaster(1);
}
/*
* Other one-time internal sanity checks can go here.
*/
if (!CheckDateTokenTables())
{
postmaster_error("invalid datetoken tables, please fix");
ExitPostmaster(1);
}
/*
* Now that we are done processing the postmaster arguments, reset
* getopt(3) library so that it will work correctly in subprocesses.
*/
optind = 1;
#ifdef HAVE_INT_OPTRESET
optreset = 1; /* some systems need this too */
#endif
/* For debugging: display postmaster environment */
{
extern char **environ;
char **p;
ereport(DEBUG3,
(errmsg_internal("%s: PostmasterMain: initial environ dump:",
progname)));
ereport(DEBUG3,
(errmsg_internal("-----------------------------------------")));
for (p = environ; *p; ++p)
ereport(DEBUG3,
(errmsg_internal("\t%s", *p)));
ereport(DEBUG3,
(errmsg_internal("-----------------------------------------")));
}
#ifdef EXEC_BACKEND
if (find_other_exec(argv[0], "postgres", PG_VERSIONSTR, postgres_exec_path) < 0)
ereport(FATAL,
(errmsg("%s: could not locate postgres executable or non-matching version",
progname)));
#endif
/*
* Initialize SSL library, if specified.
*/
#ifdef USE_SSL
if (EnableSSL)
secure_initialize();
#endif
/*
* process any libraries that should be preloaded and optionally
* pre-initialized
*/
if (preload_libraries_string)
process_preload_libraries(preload_libraries_string);
/*
* Fork away from controlling terminal, if -S specified.
*
* Must do this before we grab any interlock files, else the interlocks
* will show the wrong PID.
*/
if (SilentMode)
pmdaemonize(argc, argv);
/*
* Create lockfile for data directory.
*
* We want to do this before we try to grab the input sockets, because
* the data directory interlock is more reliable than the socket-file
* interlock (thanks to whoever decided to put socket files in /tmp
* :-(). For the same reason, it's best to grab the TCP socket before
* the Unix socket.
*/
CreateDataDirLockFile(DataDir, true);
/*
* Remove old temporary files. At this point there can be no other
* Postgres processes running in this directory, so this should be
* safe.
*/
RemovePgTempFiles();
/*
* Establish input sockets.
*/
for (i = 0; i < MAXLISTEN; i++)
ListenSocket[i] = -1;
if (ListenAddresses)
{
char *curhost,
*endptr;
char c;
curhost = ListenAddresses;
for (;;)
{
/* ignore whitespace */
while (isspace((unsigned char) *curhost))
curhost++;
if (*curhost == '\0')
break;
endptr = curhost;
while (*endptr != '\0' && !isspace((unsigned char) *endptr))
endptr++;
c = *endptr;
*endptr = '\0';
if (strcmp(curhost,"*") == 0)
status = StreamServerPort(AF_UNSPEC, NULL,
(unsigned short) PostPortNumber,
UnixSocketDir,
ListenSocket, MAXLISTEN);
else
status = StreamServerPort(AF_UNSPEC, curhost,
(unsigned short) PostPortNumber,
UnixSocketDir,
ListenSocket, MAXLISTEN);
if (status != STATUS_OK)
ereport(WARNING,
(errmsg("could not create listen socket for \"%s\"",
curhost)));
*endptr = c;
if (c != '\0')
curhost = endptr+1;
else
break;
}
}
#ifdef USE_RENDEZVOUS
/* Register for Rendezvous only if we opened TCP socket(s) */
if (ListenSocket[0] != -1 && rendezvous_name != NULL)
{
DNSServiceRegistrationCreate(rendezvous_name,
"_postgresql._tcp.",
"",
htonl(PostPortNumber),
"",
(DNSServiceRegistrationReply) reg_reply,
NULL);
}
#endif
#ifdef HAVE_UNIX_SOCKETS
status = StreamServerPort(AF_UNIX, NULL,
(unsigned short) PostPortNumber,
UnixSocketDir,
ListenSocket, MAXLISTEN);
if (status != STATUS_OK)
ereport(WARNING,
(errmsg("could not create Unix-domain socket")));
#endif
/*
* check that we have some socket to listen on
*/
if (ListenSocket[0] == -1)
ereport(FATAL,
(errmsg("no socket created for listening")));
XLOGPathInit();
/*
* Set up shared memory and semaphores.
*/
reset_shared(PostPortNumber);
/*
* Estimate number of openable files. This must happen after setting up
* semaphores, because on some platforms semaphores count as open files.
*/
set_max_safe_fds();
/*
* Initialize the list of active backends.
*/
BackendList = DLNewList();
#ifdef WIN32
/*
* Initialize the child pid/HANDLE arrays
*/
win32_childPIDArray = (pid_t*)malloc(NUM_BACKENDARRAY_ELEMS*sizeof(pid_t));
win32_childHNDArray = (HANDLE*)malloc(NUM_BACKENDARRAY_ELEMS*sizeof(HANDLE));
if (!win32_childPIDArray || !win32_childHNDArray)
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
#endif
/*
* Record postmaster options. We delay this till now to avoid
* recording bogus options (eg, NBuffers too high for available
* memory).
*/
if (!CreateOptsFile(argc, argv, my_exec_path))
ExitPostmaster(1);
/*
* Set up signal handlers for the postmaster process.
*
* CAUTION: when changing this list, check for side-effects on the signal
* handling setup of child processes. See tcop/postgres.c,
* bootstrap/bootstrap.c, and postmaster/pgstat.c.
*/
pqinitmask();
PG_SETMASK(&BlockSig);
pqsignal(SIGHUP, SIGHUP_handler); /* reread config file and have
* children do same */
pqsignal(SIGINT, pmdie); /* send SIGTERM and ShutdownDataBase */
pqsignal(SIGQUIT, pmdie); /* send SIGQUIT and die */
pqsignal(SIGTERM, pmdie); /* wait for children and ShutdownDataBase */
pqsignal(SIGALRM, SIG_IGN); /* ignored */
pqsignal(SIGPIPE, SIG_IGN); /* ignored */
pqsignal(SIGUSR1, sigusr1_handler); /* message from child process */
pqsignal(SIGUSR2, dummy_handler); /* unused, reserve for children */
pqsignal(SIGCHLD, reaper); /* handle child termination */
pqsignal(SIGTTIN, SIG_IGN); /* ignored */
pqsignal(SIGTTOU, SIG_IGN); /* ignored */
/* ignore SIGXFSZ, so that ulimit violations work like disk full */
#ifdef SIGXFSZ
pqsignal(SIGXFSZ, SIG_IGN); /* ignored */
#endif
/*
* Reset whereToSendOutput from Debug (its starting state) to None.
* This prevents ereport from sending log messages to stderr unless
* the syslog/stderr switch permits. We don't do this until the
* postmaster is fully launched, since startup failures may as well be
* reported to stderr.
*/
whereToSendOutput = None;
/*
* On many platforms, the first call of localtime() incurs significant
* overhead to load timezone info from the system configuration files.
* By doing it once in the postmaster, we avoid having to do it in
* every started child process. The savings are not huge, but they
* add up...
*/
{
time_t now = time(NULL);
(void) pg_localtime(&now);
}
/*
* Initialize and try to startup the statistics collector process
*/
pgstat_init();
pgstat_start();
/*
* Load cached files for client authentication.
*/
load_hba();
load_ident();
load_user();
load_group();
/*
* We're ready to rock and roll...
*/
StartupPID = StartupDataBase();
status = ServerLoop();
/*
* ServerLoop probably shouldn't ever return, but if it does, close
* down.
*/
ExitPostmaster(status != STATUS_OK);
return 0; /* not reached */
}
static void
pmdaemonize(int argc, char *argv[])
{
#ifdef WIN32
/* not supported */
elog(FATAL,"SilentMode not supported under WIN32");
#else
int i;
pid_t pid;
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
#ifdef LINUX_PROFILE
/* see comments in BackendRun */
getitimer(ITIMER_PROF, &prof_itimer);
#endif
pid = fork();
if (pid == (pid_t) -1)
{
postmaster_error("could not fork background process: %s",
strerror(errno));
ExitPostmaster(1);
}
else if (pid)
{ /* parent */
/* Parent should just exit, without doing any atexit cleanup */
_exit(0);
}
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
MyProcPid = getpid(); /* reset MyProcPid to child */
/* GH: If there's no setsid(), we hopefully don't need silent mode.
* Until there's a better solution.
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
{
postmaster_error("could not dissociate from controlling TTY: %s",
strerror(errno));
ExitPostmaster(1);
}
#endif
i = open(NULL_DEV, O_RDWR | PG_BINARY);
dup2(i, 0);
dup2(i, 1);
dup2(i, 2);
close(i);
#endif
}
/*
* Print out help message
*/
static void
usage(const char *progname)
{
printf(gettext("%s is the PostgreSQL server.\n\n"), progname);
printf(gettext("Usage:\n %s [OPTION]...\n\n"), progname);
printf(gettext("Options:\n"));
#ifdef USE_ASSERT_CHECKING
printf(gettext(" -A 1|0 enable/disable run-time assert checking\n"));
#endif
printf(gettext(" -B NBUFFERS number of shared buffers\n"));
printf(gettext(" -c NAME=VALUE set run-time parameter\n"));
printf(gettext(" -d 1-5 debugging level\n"));
printf(gettext(" -D DATADIR database directory\n"));
printf(gettext(" -F turn fsync off\n"));
printf(gettext(" -h HOSTNAME host name or IP address to listen on\n"));
printf(gettext(" -i enable TCP/IP connections\n"));
printf(gettext(" -k DIRECTORY Unix-domain socket location\n"));
#ifdef USE_SSL
printf(gettext(" -l enable SSL connections\n"));
#endif
printf(gettext(" -N MAX-CONNECT maximum number of allowed connections\n"));
printf(gettext(" -o OPTIONS pass \"OPTIONS\" to each server process\n"));
printf(gettext(" -p PORT port number to listen on\n"));
printf(gettext(" -S silent mode (start in background without logging output)\n"));
printf(gettext(" --help show this help, then exit\n"));
printf(gettext(" --version output version information, then exit\n"));
printf(gettext("\nDeveloper options:\n"));
printf(gettext(" -n do not reinitialize shared memory after abnormal exit\n"));
printf(gettext(" -s send SIGSTOP to all backend servers if one dies\n"));
printf(gettext("\nPlease read the documentation for the complete list of run-time\n"
"configuration settings and how to set them on the command line or in\n"
"the configuration file.\n\n"
"Report bugs to <pgsql-bugs@postgresql.org>.\n"));
}
static int
ServerLoop(void)
{
fd_set readmask;
int nSockets;
struct timeval now,
later;
struct timezone tz;
int i;
gettimeofday(&now, &tz);
nSockets = initMasks(&readmask);
for (;;)
{
Port *port;
fd_set rmask;
struct timeval timeout;
/*
* The timeout for the select() below is normally set on the basis
* of the time to the next checkpoint. However, if for some
* reason we don't have a next-checkpoint time, time out after 60
* seconds. This keeps checkpoint scheduling from locking up when
* we get new connection requests infrequently (since we are
* likely to detect checkpoint completion just after enabling
* signals below, after we've already made the decision about how
* long to wait this time).
*/
timeout.tv_sec = 60;
timeout.tv_usec = 0;
if (CheckPointPID == 0 && checkpointed &&
StartupPID == 0 && Shutdown == NoShutdown &&
!FatalError && random_seed != 0)
{
time_t now = time(NULL);
if (CheckPointTimeout + checkpointed > now)
{
/*
* Not time for checkpoint yet, so set select timeout
*/
timeout.tv_sec = CheckPointTimeout + checkpointed - now;
}
else
{
/* Time to make the checkpoint... */
CheckPointPID = CheckPointDataBase();
/*
* if fork failed, schedule another try at 0.1 normal
* delay
*/
if (CheckPointPID == 0)
{
timeout.tv_sec = CheckPointTimeout / 10;
checkpointed = now + timeout.tv_sec - CheckPointTimeout;
}
}
}
/*
* If no background writer process is running and we should
* do background writing, start one. It doesn't matter if
* this fails, we'll just try again later.
*/
if (BgWriterPID == 0 && BgWriterPercent > 0 &&
StartupPID == 0 && Shutdown == NoShutdown &&
!FatalError && random_seed != 0)
{
BgWriterPID = StartBackgroundWriter();
}
/*
* Wait for something to happen.
*/
memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set));
PG_SETMASK(&UnBlockSig);
if (select(nSockets, &rmask, NULL, NULL, &timeout) < 0)
{
PG_SETMASK(&BlockSig);
if (errno == EINTR || errno == EWOULDBLOCK)
continue;
ereport(LOG,
(errcode_for_socket_access(),
errmsg("select() failed in postmaster: %m")));
return STATUS_ERROR;
}
/*
* Block all signals until we wait again. (This makes it safe for
* our signal handlers to do nontrivial work.)
*/
PG_SETMASK(&BlockSig);
/*
* Select a random seed at the time of first receiving a request.
*/
while (random_seed == 0)
{
gettimeofday(&later, &tz);
/*
* We are not sure how much precision is in tv_usec, so we
* swap the nibbles of 'later' and XOR them with 'now'. On the
* off chance that the result is 0, we loop until it isn't.
*/
random_seed = now.tv_usec ^
((later.tv_usec << 16) |
((later.tv_usec >> 16) & 0xffff));
}
/*
* New connection pending on any of our sockets? If so, fork a
* child process to deal with it.
*/
for (i = 0; i < MAXLISTEN; i++)
{
if (ListenSocket[i] == -1)
break;
if (FD_ISSET(ListenSocket[i], &rmask))
{
port = ConnCreate(ListenSocket[i]);
if (port)
{
BackendStartup(port);
/*
* We no longer need the open socket or port structure
* in this process
*/
StreamClose(port->sock);
ConnFree(port);
}
}
}
/* If we have lost the stats collector, try to start a new one */
if (!pgstat_is_running)
pgstat_start();
}
}
/*
* Initialise the masks for select() for the ports
* we are listening on. Return the number of sockets to listen on.
*/
static int
initMasks(fd_set *rmask)
{
int nsocks = -1;
int i;
FD_ZERO(rmask);
for (i = 0; i < MAXLISTEN; i++)
{
int fd = ListenSocket[i];
if (fd == -1)
break;
FD_SET(fd, rmask);
if (fd > nsocks)
nsocks = fd;
}
return nsocks + 1;
}
/*
* Read the startup packet and do something according to it.
*
* Returns STATUS_OK or STATUS_ERROR, or might call ereport(FATAL) and
* not return at all.
*
* (Note that ereport(FATAL) stuff is sent to the client, so only use it
* if that's what you want. Return STATUS_ERROR if you don't want to
* send anything to the client, which would typically be appropriate
* if we detect a communications failure.)
*/
static int
ProcessStartupPacket(Port *port, bool SSLdone)
{
int32 len;
void *buf;
ProtocolVersion proto;
MemoryContext oldcontext;
if (pq_getbytes((char *) &len, 4) == EOF)
{
/*
* EOF after SSLdone probably means the client didn't like our
* response to NEGOTIATE_SSL_CODE. That's not an error condition,
* so don't clutter the log with a complaint.
*/
if (!SSLdone)
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("incomplete startup packet")));
return STATUS_ERROR;
}
len = ntohl(len);
len -= 4;
if (len < (int32) sizeof(ProtocolVersion) ||
len > MAX_STARTUP_PACKET_LENGTH)
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid length of startup packet")));
return STATUS_ERROR;
}
/*
* Allocate at least the size of an old-style startup packet, plus one
* extra byte, and make sure all are zeroes. This ensures we will
* have null termination of all strings, in both fixed- and
* variable-length packet layouts.
*/
if (len <= (int32) sizeof(StartupPacket))
buf = palloc0(sizeof(StartupPacket) + 1);
else
buf = palloc0(len + 1);
if (pq_getbytes(buf, len) == EOF)
{
ereport(COMMERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("incomplete startup packet")));
return STATUS_ERROR;
}
/*
* The first field is either a protocol version number or a special
* request code.
*/
port->proto = proto = ntohl(*((ProtocolVersion *) buf));
if (proto == CANCEL_REQUEST_CODE)
{
processCancelRequest(port, buf);
return 127; /* XXX */
}
if (proto == NEGOTIATE_SSL_CODE && !SSLdone)
{
char SSLok;
#ifdef USE_SSL
/* No SSL when disabled or on Unix sockets */
if (!EnableSSL || IS_AF_UNIX(port->laddr.addr.ss_family))
SSLok = 'N';
else
SSLok = 'S'; /* Support for SSL */
#else
SSLok = 'N'; /* No support for SSL */
#endif
if (send(port->sock, &SSLok, 1, 0) != 1)
{
ereport(COMMERROR,
(errcode_for_socket_access(),
errmsg("failed to send SSL negotiation response: %m")));
return STATUS_ERROR; /* close the connection */
}
#ifdef USE_SSL
if (SSLok == 'S' && secure_open_server(port) == -1)
return STATUS_ERROR;
#endif
/* regular startup packet, cancel, etc packet should follow... */
/* but not another SSL negotiation request */
return ProcessStartupPacket(port, true);
}
/* Could add additional special packet types here */
/*
* Set FrontendProtocol now so that ereport() knows what format to
* send if we fail during startup.
*/
FrontendProtocol = proto;
/* Check we can handle the protocol the frontend is using. */
if (PG_PROTOCOL_MAJOR(proto) < PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST) ||
PG_PROTOCOL_MAJOR(proto) > PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST) ||
(PG_PROTOCOL_MAJOR(proto) == PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST) &&
PG_PROTOCOL_MINOR(proto) > PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST)))
ereport(FATAL,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unsupported frontend protocol %u.%u: server supports %u.0 to %u.%u",
PG_PROTOCOL_MAJOR(proto), PG_PROTOCOL_MINOR(proto),
PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST),
PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST),
PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST))));
/*
* Now fetch parameters out of startup packet and save them into the
* Port structure. All data structures attached to the Port struct
* must be allocated in TopMemoryContext so that they won't disappear
* when we pass them to PostgresMain (see BackendRun). We need not
* worry about leaking this storage on failure, since we aren't in the
* postmaster process anymore.
*/
oldcontext = MemoryContextSwitchTo(TopMemoryContext);
if (PG_PROTOCOL_MAJOR(proto) >= 3)
{
int32 offset = sizeof(ProtocolVersion);
/*
* Scan packet body for name/option pairs. We can assume any
* string beginning within the packet body is null-terminated,
* thanks to zeroing extra byte above.
*/
port->guc_options = NIL;
while (offset < len)
{
char *nameptr = ((char *) buf) + offset;
int32 valoffset;
char *valptr;
if (*nameptr == '\0')
break; /* found packet terminator */
valoffset = offset + strlen(nameptr) + 1;
if (valoffset >= len)
break; /* missing value, will complain below */
valptr = ((char *) buf) + valoffset;
if (strcmp(nameptr, "database") == 0)
port->database_name = pstrdup(valptr);
else if (strcmp(nameptr, "user") == 0)
port->user_name = pstrdup(valptr);
else if (strcmp(nameptr, "options") == 0)
port->cmdline_options = pstrdup(valptr);
else
{
/* Assume it's a generic GUC option */
port->guc_options = lappend(port->guc_options,
pstrdup(nameptr));
port->guc_options = lappend(port->guc_options,
pstrdup(valptr));
}
offset = valoffset + strlen(valptr) + 1;
}
/*
* If we didn't find a packet terminator exactly at the end of the
* given packet length, complain.
*/
if (offset != len - 1)
ereport(FATAL,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("invalid startup packet layout: expected terminator as last byte")));
}
else
{
/*
* Get the parameters from the old-style, fixed-width-fields
* startup packet as C strings. The packet destination was
* cleared first so a short packet has zeros silently added. We
* have to be prepared to truncate the pstrdup result for oversize
* fields, though.
*/
StartupPacket *packet = (StartupPacket *) buf;
port->database_name = pstrdup(packet->database);
if (strlen(port->database_name) > sizeof(packet->database))
port->database_name[sizeof(packet->database)] = '\0';
port->user_name = pstrdup(packet->user);
if (strlen(port->user_name) > sizeof(packet->user))
port->user_name[sizeof(packet->user)] = '\0';
port->cmdline_options = pstrdup(packet->options);
if (strlen(port->cmdline_options) > sizeof(packet->options))
port->cmdline_options[sizeof(packet->options)] = '\0';
port->guc_options = NIL;
}
/* Check a user name was given. */
if (port->user_name == NULL || port->user_name[0] == '\0')
ereport(FATAL,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
errmsg("no PostgreSQL user name specified in startup packet")));
/* The database defaults to the user name. */
if (port->database_name == NULL || port->database_name[0] == '\0')
port->database_name = pstrdup(port->user_name);
if (Db_user_namespace)
{
/*
* If user@, it is a global user, remove '@'. We only want to do
* this if there is an '@' at the end and no earlier in the user
* string or they may fake as a local user of another database
* attaching to this database.
*/
if (strchr(port->user_name, '@') ==
port->user_name + strlen(port->user_name) - 1)
*strchr(port->user_name, '@') = '\0';
else
{
/* Append '@' and dbname */
char *db_user;
db_user = palloc(strlen(port->user_name) +
strlen(port->database_name) + 2);
sprintf(db_user, "%s@%s", port->user_name, port->database_name);
port->user_name = db_user;
}
}
/*
* Truncate given database and user names to length of a Postgres
* name. This avoids lookup failures when overlength names are given.
*/
if (strlen(port->database_name) >= NAMEDATALEN)
port->database_name[NAMEDATALEN - 1] = '\0';
if (strlen(port->user_name) >= NAMEDATALEN)
port->user_name[NAMEDATALEN - 1] = '\0';
/*
* Done putting stuff in TopMemoryContext.
*/
MemoryContextSwitchTo(oldcontext);
/*
* If we're going to reject the connection due to database state, say
* so now instead of wasting cycles on an authentication exchange.
* (This also allows a pg_ping utility to be written.)
*/
switch (port->canAcceptConnections)
{
case CAC_STARTUP:
ereport(FATAL,
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
errmsg("the database system is starting up")));
break;
case CAC_SHUTDOWN:
ereport(FATAL,
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
errmsg("the database system is shutting down")));
break;
case CAC_RECOVERY:
ereport(FATAL,
(errcode(ERRCODE_CANNOT_CONNECT_NOW),
errmsg("the database system is in recovery mode")));
break;
case CAC_TOOMANY:
ereport(FATAL,
(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
errmsg("sorry, too many clients already")));
break;
case CAC_OK:
default:
break;
}
return STATUS_OK;
}
/*
* The client has sent a cancel request packet, not a normal
* start-a-new-connection packet. Perform the necessary processing.
* Nothing is sent back to the client.
*/
static void
processCancelRequest(Port *port, void *pkt)
{
CancelRequestPacket *canc = (CancelRequestPacket *) pkt;
int backendPID;
long cancelAuthCode;
Backend *bp;
#ifndef EXEC_BACKEND
Dlelem *curr;
#else
int i;
#endif
backendPID = (int) ntohl(canc->backendPID);
cancelAuthCode = (long) ntohl(canc->cancelAuthCode);
if (backendPID == CheckPointPID)
{
ereport(DEBUG2,
(errmsg_internal("ignoring cancel request for checkpoint process %d",
backendPID)));
return;
}
else if (backendPID == BgWriterPID)
{
ereport(DEBUG2,
(errmsg_internal("ignoring cancel request for bgwriter process %d",
backendPID)));
return;
}
/* See if we have a matching backend */
#ifndef EXEC_BACKEND
for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
{
bp = (Backend *) DLE_VAL(curr);
#else
for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
{
bp = (Backend*) &ShmemBackendArray[i];
#endif
if (bp->pid == backendPID)
{
if (bp->cancel_key == cancelAuthCode)
{
/* Found a match; signal that backend to cancel current op */
ereport(DEBUG2,
(errmsg_internal("processing cancel request: sending SIGINT to process %d",
backendPID)));
kill(bp->pid, SIGINT);
}
else
/* Right PID, wrong key: no way, Jose */
ereport(DEBUG2,
(errmsg_internal("bad key in cancel request for process %d",
backendPID)));
return;
}
}
/* No matching backend */
ereport(DEBUG2,
(errmsg_internal("bad pid in cancel request for process %d",
backendPID)));
}
/*
* canAcceptConnections --- check to see if database state allows connections.
*/
static enum CAC_state
canAcceptConnections(void)
{
/* Can't start backends when in startup/shutdown/recovery state. */
if (Shutdown > NoShutdown)
return CAC_SHUTDOWN;
if (StartupPID)
return CAC_STARTUP;
if (FatalError)
return CAC_RECOVERY;
/*
* Don't start too many children.
*
* We allow more connections than we can have backends here because some
* might still be authenticating; they might fail auth, or some
* existing backend might exit before the auth cycle is completed. The
* exact MaxBackends limit is enforced when a new backend tries to
* join the shared-inval backend array.
*/
if (CountChildren() >= 2 * MaxBackends)
return CAC_TOOMANY;
return CAC_OK;
}
/*
* ConnCreate -- create a local connection data structure
*/
static Port *
ConnCreate(int serverFd)
{
Port *port;
if (!(port = (Port *) calloc(1, sizeof(Port))))
{
ereport(LOG,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
ExitPostmaster(1);
}
if (StreamConnection(serverFd, port) != STATUS_OK)
{
StreamClose(port->sock);
ConnFree(port);
port = NULL;
}
else
{
/*
* Precompute password salt values to use for this connection.
* It's slightly annoying to do this long in advance of knowing
* whether we'll need 'em or not, but we must do the random()
* calls before we fork, not after. Else the postmaster's random
* sequence won't get advanced, and all backends would end up
* using the same salt...
*/
RandomSalt(port->cryptSalt, port->md5Salt);
}
return port;
}
/*
* ConnFree -- free a local connection data structure
*/
static void
ConnFree(Port *conn)
{
#ifdef USE_SSL
secure_close(conn);
#endif
free(conn);
}
/*
* ClosePostmasterPorts -- close all the postmaster's open sockets
*
* This is called during child process startup to release file descriptors
* that are not needed by that child process. The postmaster still has
* them open, of course.
*/
void
ClosePostmasterPorts(bool pgstat_too)
{
int i;
/* Close the listen sockets */
for (i = 0; i < MAXLISTEN; i++)
{
if (ListenSocket[i] != -1)
{
StreamClose(ListenSocket[i]);
ListenSocket[i] = -1;
}
}
/* Close pgstat control sockets, unless we're starting pgstat itself */
if (pgstat_too)
pgstat_close_sockets();
}
/*
* reset_shared -- reset shared memory and semaphores
*/
static void
reset_shared(unsigned short port)
{
/*
* Create or re-create shared memory and semaphores.
*
* Note: in each "cycle of life" we will normally assign the same IPC
* keys (if using SysV shmem and/or semas), since the port number is
* used to determine IPC keys. This helps ensure that we will clean
* up dead IPC objects if the postmaster crashes and is restarted.
*/
CreateSharedMemoryAndSemaphores(false, MaxBackends, port);
}
/*
* SIGHUP -- reread config files, and tell children to do same
*/
static void
SIGHUP_handler(SIGNAL_ARGS)
{
int save_errno = errno;
PG_SETMASK(&BlockSig);
if (Shutdown <= SmartShutdown)
{
ereport(LOG,
(errmsg("received SIGHUP, reloading configuration files")));
ProcessConfigFile(PGC_SIGHUP);
#ifdef EXEC_BACKEND
write_nondefault_variables(PGC_SIGHUP);
#endif
SignalChildren(SIGHUP);
load_hba();
load_ident();
/*
* Tell the background writer to terminate so that we
* will start a new one with a possibly changed config
*/
if (BgWriterPID != 0)
kill(BgWriterPID, SIGTERM);
}
PG_SETMASK(&UnBlockSig);
errno = save_errno;
}
/*
* pmdie -- signal handler for processing various postmaster signals.
*/
static void
pmdie(SIGNAL_ARGS)
{
int save_errno = errno;
PG_SETMASK(&BlockSig);
ereport(DEBUG2,
(errmsg_internal("postmaster received signal %d",
postgres_signal_arg)));
switch (postgres_signal_arg)
{
case SIGTERM:
/*
* Smart Shutdown:
*
* Wait for children to end their work and ShutdownDataBase.
*/
if (Shutdown >= SmartShutdown)
break;
Shutdown = SmartShutdown;
ereport(LOG,
(errmsg("received smart shutdown request")));
/* Must tell bgwriter to quit, or it never will... */
if (BgWriterPID != 0)
kill(BgWriterPID, SIGTERM);
if (DLGetHead(BackendList)) /* let reaper() handle this */
break;
/*
* No children left. Shutdown data base system.
*/
if (StartupPID > 0 || FatalError) /* let reaper() handle
* this */
break;
if (ShutdownPID > 0)
{
elog(PANIC, "shutdown process %d already running",
(int) ShutdownPID);
abort();
}
ShutdownPID = ShutdownDataBase();
break;
case SIGINT:
/*
* Fast Shutdown:
*
* Abort all children with SIGTERM (rollback active transactions
* and exit) and ShutdownDataBase when they are gone.
*/
if (Shutdown >= FastShutdown)
break;
Shutdown = FastShutdown;
ereport(LOG,
(errmsg("received fast shutdown request")));
if (DLGetHead(BackendList))
{
if (!FatalError)
{
ereport(LOG,
(errmsg("aborting any active transactions")));
SignalChildren(SIGTERM);
/* reaper() does the rest */
}
break;
}
/*
* No children left. Shutdown data base system.
*
* Unlike the previous case, it is not an error for the shutdown
* process to be running already (we could get SIGTERM followed
* shortly later by SIGINT).
*/
if (StartupPID > 0 || FatalError) /* let reaper() handle
* this */
break;
if (ShutdownPID == 0)
ShutdownPID = ShutdownDataBase();
break;
case SIGQUIT:
/*
* Immediate Shutdown:
*
* abort all children with SIGQUIT and exit without attempt to
* properly shutdown data base system.
*/
ereport(LOG,
(errmsg("received immediate shutdown request")));
if (ShutdownPID > 0)
kill(ShutdownPID, SIGQUIT);
if (StartupPID > 0)
kill(StartupPID, SIGQUIT);
if (DLGetHead(BackendList))
SignalChildren(SIGQUIT);
ExitPostmaster(0);
break;
}
PG_SETMASK(&UnBlockSig);
errno = save_errno;
}
/*
* Reaper -- signal handler to cleanup after a backend (child) dies.
*/
static void
reaper(SIGNAL_ARGS)
{
int save_errno = errno;
#ifdef HAVE_WAITPID
int status; /* backend exit status */
#else
#ifndef WIN32
union wait status; /* backend exit status */
#endif
#endif
int exitstatus;
int pid; /* process id of dead backend */
PG_SETMASK(&BlockSig);
ereport(DEBUG4,
(errmsg_internal("reaping dead processes")));
#ifdef HAVE_WAITPID
while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
{
exitstatus = status;
#else
#ifndef WIN32
while ((pid = wait3(&status, WNOHANG, NULL)) > 0)
{
exitstatus = status.w_status;
#else
while ((pid = win32_waitpid(&exitstatus)) > 0)
{
/*
* We need to do this here, and not in CleanupProc, since this
* is to be called on all children when we are done with them.
* Could move to LogChildExit, but that seems like asking for
* future trouble...
*/
win32_RemoveChild(pid);
#endif
#endif
/*
* Check if this child was the statistics collector. If so, try to
* start a new one. (If fail, we'll try again in future cycles of
* the main loop.)
*/
if (pgstat_ispgstat(pid))
{
LogChildExit(LOG, gettext("statistics collector process"),
pid, exitstatus);
pgstat_start();
continue;
}
/*
* Check if this child was a shutdown or startup process.
*/
if (ShutdownPID > 0 && pid == ShutdownPID)
{
if (exitstatus != 0)
{
LogChildExit(LOG, gettext("shutdown process"),
pid, exitstatus);
ExitPostmaster(1);
}
/* Normal postmaster exit is here */
ExitPostmaster(0);
}
if (StartupPID > 0 && pid == StartupPID)
{
if (exitstatus != 0)
{
LogChildExit(LOG, gettext("startup process"),
pid, exitstatus);
ereport(LOG,
(errmsg("aborting startup due to startup process failure")));
ExitPostmaster(1);
}
StartupPID = 0;
/*
* Startup succeeded - remember its ID and RedoRecPtr.
*
* NB: this MUST happen before we fork a checkpoint or shutdown
* subprocess, else they will have wrong local ThisStartUpId.
*/
SetThisStartUpID();
FatalError = false; /* done with recovery */
/*
* Arrange for first checkpoint to occur after standard delay.
*/
CheckPointPID = 0;
checkpointed = time(NULL);
/*
* Go to shutdown mode if a shutdown request was pending.
*/
if (Shutdown > NoShutdown)
{
if (ShutdownPID > 0)
{
elog(PANIC, "startup process %d died while shutdown process %d already running",
pid, (int) ShutdownPID);
abort();
}
ShutdownPID = ShutdownDataBase();
}
goto reaper_done;
}
/*
* Else do standard child cleanup.
*/
CleanupProc(pid, exitstatus);
} /* loop over pending child-death reports */
if (FatalError)
{
/*
* Wait for all children exit, then reset shmem and
* StartupDataBase.
*/
if (DLGetHead(BackendList) || StartupPID > 0 || ShutdownPID > 0)
goto reaper_done;
ereport(LOG,
(errmsg("all server processes terminated; reinitializing")));
shmem_exit(0);
reset_shared(PostPortNumber);
StartupPID = StartupDataBase();
goto reaper_done;
}
if (Shutdown > NoShutdown)
{
if (DLGetHead(BackendList))
goto reaper_done;
if (StartupPID > 0 || ShutdownPID > 0)
goto reaper_done;
ShutdownPID = ShutdownDataBase();
}
reaper_done:
PG_SETMASK(&UnBlockSig);
errno = save_errno;
}
/*
* CleanupProc -- cleanup after terminated backend.
*
* Remove all local state associated with backend.
*/
static void
CleanupProc(int pid,
int exitstatus) /* child's exit status. */
{
Dlelem *curr,
*next;
Backend *bp;
LogChildExit(DEBUG2, gettext("child process"), pid, exitstatus);
/*
* If a backend dies in an ugly way (i.e. exit status not 0) then we
* must signal all other backends to quickdie. If exit status is zero
* we assume everything is hunky dory and simply remove the backend
* from the active backend list.
*/
if (exitstatus == 0)
{
curr = DLGetHead(BackendList);
while (curr)
{
bp = (Backend *) DLE_VAL(curr);
if (bp->pid == pid)
{
#ifdef EXEC_BACKEND
ShmemBackendArrayRemove(bp->pid);
#endif
DLRemove(curr);
free(bp);
DLFreeElem(curr);
break;
}
curr = DLGetSucc(curr);
}
if (pid == CheckPointPID)
{
CheckPointPID = 0;
if (!FatalError)
{
checkpointed = time(NULL);
/* Update RedoRecPtr for future child backends */
GetSavedRedoRecPtr();
}
}
else if (pid == BgWriterPID)
BgWriterPID = 0;
else
pgstat_beterm(pid);
return;
}
/* below here we're dealing with a non-normal exit */
/* Make log entry unless we did so already */
if (!FatalError)
{
LogChildExit(LOG,
(pid == CheckPointPID) ? gettext("checkpoint process") :
(pid == BgWriterPID) ? gettext("bgwriter process") :
gettext("server process"),
pid, exitstatus);
ereport(LOG,
(errmsg("terminating any other active server processes")));
}
curr = DLGetHead(BackendList);
while (curr)
{
next = DLGetSucc(curr);
bp = (Backend *) DLE_VAL(curr);
if (bp->pid != pid)
{
/*
* This backend is still alive. Unless we did so already,
* tell it to commit hara-kiri.
*
* SIGQUIT is the special signal that says exit without proc_exit
* and let the user know what's going on. But if SendStop is
* set (-s on command line), then we send SIGSTOP instead, so
* that we can get core dumps from all backends by hand.
*/
if (!FatalError)
{
ereport(DEBUG2,
(errmsg_internal("sending %s to process %d",
(SendStop ? "SIGSTOP" : "SIGQUIT"),
(int) bp->pid)));
kill(bp->pid, (SendStop ? SIGSTOP : SIGQUIT));
}
}
else
{
/*
* Found entry for freshly-dead backend, so remove it.
*/
#ifdef EXEC_BACKEND
ShmemBackendArrayRemove(bp->pid);
#endif
DLRemove(curr);
free(bp);
DLFreeElem(curr);
}
curr = next;
}
if (pid == CheckPointPID)
{
CheckPointPID = 0;
checkpointed = 0;
}
else if (pid == BgWriterPID)
{
BgWriterPID = 0;
}
else
{
/*
* Tell the collector about backend termination
*/
pgstat_beterm(pid);
}
FatalError = true;
}
/*
* Log the death of a child process.
*/
static void
LogChildExit(int lev, const char *procname, int pid, int exitstatus)
{
if (WIFEXITED(exitstatus))
ereport(lev,
/*
* translator: %s is a noun phrase describing a child process,
* such as "server process"
*/
(errmsg("%s (PID %d) exited with exit code %d",
procname, pid, WEXITSTATUS(exitstatus))));
else if (WIFSIGNALED(exitstatus))
ereport(lev,
/*
* translator: %s is a noun phrase describing a child process,
* such as "server process"
*/
(errmsg("%s (PID %d) was terminated by signal %d",
procname, pid, WTERMSIG(exitstatus))));
else
ereport(lev,
/*
* translator: %s is a noun phrase describing a child process,
* such as "server process"
*/
(errmsg("%s (PID %d) exited with unexpected status %d",
procname, pid, exitstatus)));
}
/*
* Send a signal to all backend children.
*/
static void
SignalChildren(int signal)
{
Dlelem *curr,
*next;
Backend *bp;
curr = DLGetHead(BackendList);
while (curr)
{
next = DLGetSucc(curr);
bp = (Backend *) DLE_VAL(curr);
if (bp->pid != MyProcPid)
{
ereport(DEBUG2,
(errmsg_internal("sending signal %d to process %d",
signal,
(int) bp->pid)));
kill(bp->pid, signal);
}
curr = next;
}
}
/*
* BackendStartup -- start backend process
*
* returns: STATUS_ERROR if the fork failed, STATUS_OK otherwise.
*/
static int
BackendStartup(Port *port)
{
Backend *bn; /* for backend cleanup */
pid_t pid;
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
/*
* Compute the cancel key that will be assigned to this backend. The
* backend will have its own copy in the forked-off process' value of
* MyCancelKey, so that it can transmit the key to the frontend.
*/
MyCancelKey = PostmasterRandom();
/*
* Make room for backend data structure. Better before the fork() so
* we can handle failure cleanly.
*/
bn = (Backend *) malloc(sizeof(Backend));
if (!bn)
{
ereport(LOG,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
return STATUS_ERROR;
}
/*
* Flush stdio channels just before fork, to avoid double-output
* problems. Ideally we'd use fflush(NULL) here, but there are still a
* few non-ANSI stdio libraries out there (like SunOS 4.1.x) that
* coredump if we do. Presently stdout and stderr are the only stdio
* output channels used by the postmaster, so fflush'ing them should
* be sufficient.
*/
fflush(stdout);
fflush(stderr);
#ifdef LINUX_PROFILE
/*
* Linux's fork() resets the profiling timer in the child process. If
* we want to profile child processes then we need to save and restore
* the timer setting. This is a waste of time if not profiling,
* however, so only do it if commanded by specific -DLINUX_PROFILE
* switch.
*/
getitimer(ITIMER_PROF, &prof_itimer);
#endif
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_before_backend_startup();
#endif
port->canAcceptConnections = canAcceptConnections();
#ifdef EXEC_BACKEND
pid = Backend_forkexec(port);
#else
pid = fork();
if (pid == 0) /* child */
{
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup();
#endif
free(bn);
proc_exit(BackendRun(port));
}
#endif
/* in parent, error */
if (pid < 0)
{
int save_errno = errno;
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup_failed();
#endif
free(bn);
errno = save_errno;
ereport(LOG,
(errmsg("could not fork new process for connection: %m")));
report_fork_failure_to_client(port, save_errno);
return STATUS_ERROR;
}
/* in parent, normal */
ereport(DEBUG2,
(errmsg_internal("forked new backend, pid=%d socket=%d",
(int) pid, port->sock)));
/*
* Everything's been successful, it's safe to add this backend to our
* list of backends.
*/
bn->pid = pid;
bn->cancel_key = MyCancelKey;
#ifdef EXEC_BACKEND
ShmemBackendArrayAdd(bn);
#endif
DLAddHead(BackendList, DLNewElem(bn));
return STATUS_OK;
}
/*
* Try to report backend fork() failure to client before we close the
* connection. Since we do not care to risk blocking the postmaster on
* this connection, we set the connection to non-blocking and try only once.
*
* This is grungy special-purpose code; we cannot use backend libpq since
* it's not up and running.
*/
static void
report_fork_failure_to_client(Port *port, int errnum)
{
char buffer[1000];
/* Format the error message packet (always V2 protocol) */
snprintf(buffer, sizeof(buffer), "E%s%s\n",
gettext("could not fork new process for connection: "),
strerror(errnum));
/* Set port to non-blocking. Don't do send() if this fails */
if (!set_noblock(port->sock))
return;
send(port->sock, buffer, strlen(buffer) + 1, 0);
}
/*
* split_opts -- split a string of options and append it to an argv array
*
* NB: the string is destructively modified!
*
* Since no current POSTGRES arguments require any quoting characters,
* we can use the simple-minded tactic of assuming each set of space-
* delimited characters is a separate argv element.
*
* If you don't like that, well, we *used* to pass the whole option string
* as ONE argument to execl(), which was even less intelligent...
*/
static void
split_opts(char **argv, int *argcp, char *s)
{
while (s && *s)
{
while (isspace((unsigned char) *s))
++s;
if (*s == '\0')
break;
argv[(*argcp)++] = s;
while (*s && !isspace((unsigned char) *s))
++s;
if (*s)
*s++ = '\0';
}
}
/*
* BackendInit/Run -- perform authentication [BackendInit], and if successful,
* set up the backend's argument list [BackendRun] and invoke
* backend main()
*
* returns:
* Shouldn't return at all.
* If PostgresMain() fails, return status.
*/
static void
BackendInit(Port *port)
{
int status;
struct timeval now;
struct timezone tz;
char remote_host[NI_MAXHOST];
char remote_port[NI_MAXSERV];
char remote_ps_data[NI_MAXHOST];
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
ClientAuthInProgress = true; /* limit visibility of log messages */
/* We don't want the postmaster's proc_exit() handlers */
on_exit_reset();
/*
* Signal handlers setting is moved to tcop/postgres...
*/
/* save start time for end of session reporting */
gettimeofday(&(port->session_start),NULL);
/* set these to empty in case they are needed before we set them up */
port->remote_host = "";
port->remote_port = "";
port->commandTag = "";
/* Save port etc. for ps status */
MyProcPort = port;
/* Reset MyProcPid to new backend's pid */
MyProcPid = getpid();
/*
* Initialize libpq and enable reporting of ereport errors to the
* client. Must do this now because authentication uses libpq to send
* messages.
*/
pq_init(); /* initialize libpq to talk to client */
whereToSendOutput = Remote; /* now safe to ereport to client */
/*
* We arrange for a simple exit(0) if we receive SIGTERM or SIGQUIT
* during any client authentication related communication. Otherwise
* the postmaster cannot shutdown the database FAST or IMMED cleanly
* if a buggy client blocks a backend during authentication.
*/
pqsignal(SIGTERM, authdie);
pqsignal(SIGQUIT, authdie);
pqsignal(SIGALRM, authdie);
PG_SETMASK(&AuthBlockSig);
/*
* Get the remote host name and port for logging and status display.
*/
remote_host[0] = '\0';
remote_port[0] = '\0';
if (getnameinfo_all(&port->raddr.addr, port->raddr.salen,
remote_host, sizeof(remote_host),
remote_port, sizeof(remote_port),
(log_hostname ? 0 : NI_NUMERICHOST) | NI_NUMERICSERV))
{
getnameinfo_all(&port->raddr.addr, port->raddr.salen,
remote_host, sizeof(remote_host),
remote_port, sizeof(remote_port),
NI_NUMERICHOST | NI_NUMERICSERV);
}
snprintf(remote_ps_data, sizeof(remote_ps_data),
remote_port[0] == '\0' ? "%s" : "%s(%s)",
remote_host, remote_port);
if (Log_connections)
ereport(LOG,
(errmsg("connection received: host=%s port=%s",
remote_host, remote_port)));
/*
* save remote_host and remote_port in port stucture
*/
port->remote_host = strdup(remote_host);
port->remote_port = strdup(remote_port);
/*
* Ready to begin client interaction. We will give up and exit(0)
* after a time delay, so that a broken client can't hog a connection
* indefinitely. PreAuthDelay doesn't count against the time limit.
*/
if (!enable_sig_alarm(AuthenticationTimeout * 1000, false))
elog(FATAL, "could not set timer for authorization timeout");
/*
* Receive the startup packet (which might turn out to be a cancel
* request packet).
*/
status = ProcessStartupPacket(port, false);
if (status != STATUS_OK)
proc_exit(0);
/*
* Now that we have the user and database name, we can set the process
* title for ps. It's good to do this as early as possible in
* startup.
*/
init_ps_display(port->user_name, port->database_name, remote_ps_data);
set_ps_display("authentication");
/*
* Now perform authentication exchange.
*/
ClientAuthentication(port); /* might not return, if failure */
/*
* Done with authentication. Disable timeout, and prevent
* SIGTERM/SIGQUIT again until backend startup is complete.
*/
if (!disable_sig_alarm(false))
elog(FATAL, "could not disable timer for authorization timeout");
PG_SETMASK(&BlockSig);
if (Log_connections)
ereport(LOG,
(errmsg("connection authorized: user=%s database=%s",
port->user_name, port->database_name)));
/*
* Don't want backend to be able to see the postmaster random number
* generator state. We have to clobber the static random_seed *and*
* start a new random sequence in the random() library function.
*/
random_seed = 0;
gettimeofday(&now, &tz);
srandom((unsigned int) now.tv_usec);
}
static int
BackendRun(Port *port)
{
char **av;
int maxac;
int ac;
char debugbuf[32];
char protobuf[32];
int i;
/*
* Let's clean up ourselves as the postmaster child, and
* close the postmaster's other sockets
*/
ClosePostmasterPorts(true);
/*
* PreAuthDelay is a debugging aid for investigating problems in the
* authentication cycle: it can be set in postgresql.conf to allow
* time to attach to the newly-forked backend with a debugger. (See
* also the -W backend switch, which we allow clients to pass through
* PGOPTIONS, but it is not honored until after authentication.)
*/
if (PreAuthDelay > 0)
pg_usleep(PreAuthDelay*1000000L);
/* Will exit on failure */
BackendInit(port);
/* ----------------
* Now, build the argv vector that will be given to PostgresMain.
*
* The layout of the command line is
* postgres [secure switches] -p databasename [insecure switches]
* where the switches after -p come from the client request.
*
* The maximum possible number of commandline arguments that could come
* from ExtraOptions or port->cmdline_options is (strlen + 1) / 2; see
* split_opts().
* ----------------
*/
maxac = 10; /* for fixed args supplied below */
maxac += (strlen(ExtraOptions) + 1) / 2;
if (port->cmdline_options)
maxac += (strlen(port->cmdline_options) + 1) / 2;
av = (char **) MemoryContextAlloc(TopMemoryContext,
maxac * sizeof(char *));
ac = 0;
av[ac++] = "postgres";
/*
* Pass the requested debugging level along to the backend.
*/
if (debug_flag > 0)
{
snprintf(debugbuf, sizeof(debugbuf), "-d%d", debug_flag);
av[ac++] = debugbuf;
}
/*
* Pass any backend switches specified with -o in the postmaster's own
* command line. We assume these are secure.
*/
split_opts(av, &ac, ExtraOptions);
/* Tell the backend what protocol the frontend is using. */
snprintf(protobuf, sizeof(protobuf), "-v%u", port->proto);
av[ac++] = protobuf;
#ifdef EXEC_BACKEND
/* pass data dir before end of secure switches (-p) */
av[ac++] = "-D";
av[ac++] = DataDir;
#endif
/*
* Tell the backend it is being called from the postmaster, and which
* database to use. -p marks the end of secure switches.
*/
av[ac++] = "-p";
av[ac++] = port->database_name;
/*
* Pass the (insecure) option switches from the connection request.
* (It's OK to mangle port->cmdline_options now.)
*/
if (port->cmdline_options)
split_opts(av, &ac, port->cmdline_options);
av[ac] = NULL;
Assert(ac < maxac);
/*
* Release postmaster's working memory context so that backend can
* recycle the space. Note this does not trash *MyProcPort, because
* ConnCreate() allocated that space with malloc() ... else we'd need
* to copy the Port data here. Also, subsidiary data such as the
* username isn't lost either; see ProcessStartupPacket().
*/
MemoryContextSwitchTo(TopMemoryContext);
#ifndef EXEC_BACKEND
MemoryContextDelete(PostmasterContext);
#endif
PostmasterContext = NULL;
/*
* Debug: print arguments being passed to backend
*/
ereport(DEBUG3,
(errmsg_internal("%s child[%d]: starting with (",
progname, getpid())));
for (i = 0; i < ac; ++i)
ereport(DEBUG3,
(errmsg_internal("\t%s", av[i])));
ereport(DEBUG3,
(errmsg_internal(")")));
ClientAuthInProgress = false; /* client_min_messages is active
* now */
return (PostgresMain(ac, av, port->user_name));
}
#ifdef EXEC_BACKEND
/*
* SubPostmasterMain -- prepare the fork/exec'd process to be in an equivalent
* state (for calling BackendRun) as a forked process.
*
* returns:
* Shouldn't return at all.
*/
void
SubPostmasterMain(int argc, char* argv[])
{
unsigned long backendID;
Port port;
memset((void*)&port, 0, sizeof(Port));
Assert(argc == 2);
/* Do this sooner rather than later... */
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
/* In EXEC case we will not have inherited these settings */
IsPostmasterEnvironment = true;
whereToSendOutput = None;
/* Setup global context */
MemoryContextInit();
InitializeGUCOptions();
/* Parse passed-in context */
argc = 0;
backendID = (unsigned long)atol(argv[argc++]);
DataDir = strdup(argv[argc++]);
/* Read in file-based context */
read_backend_variables(backendID,&port);
read_nondefault_variables();
/* Remaining initialization */
pgstat_init_forkexec_backend();
/* FIXME: [fork/exec] Ugh */
load_hba();
load_ident();
load_user();
load_group();
/* Attach process to shared segments */
CreateSharedMemoryAndSemaphores(false, MaxBackends, 0);
/* Run backend */
proc_exit(BackendRun(&port));
}
/*
* Backend_forkexec -- fork/exec off a backend process
*
* returns:
* the pid of the fork/exec'd process
*/
static pid_t
Backend_forkexec(Port *port)
{
pid_t pid;
char *av[5];
int ac = 0, bufc = 0, i;
char buf[2][MAXPGPATH];
if (!write_backend_variables(port))
return -1; /* log made by write_backend_variables */
av[ac++] = "postgres";
av[ac++] = "-forkexec";
/* Format up context to pass to exec'd process */
snprintf(buf[bufc++],MAXPGPATH,"%lu",tmpBackendFileNum);
snprintf(buf[bufc++],MAXPGPATH,"\"%s\"",DataDir);
/* Add to the arg list */
Assert(bufc <= lengthof(buf));
for (i = 0; i < bufc; i++)
av[ac++] = buf[i];
/* FIXME: [fork/exec] ExtraOptions? */
av[ac++] = NULL;
Assert(ac <= lengthof(av));
#ifdef WIN32
pid = win32_forkexec(postgres_exec_path, av); /* logs on error */
#else
/* Fire off execv in child */
if ((pid = fork()) == 0 && (execv(postgres_exec_path, av) == -1))
/*
* FIXME: [fork/exec] suggestions for what to do here?
* Probably OK to issue error (unlike pgstat case)
*/
abort();
#endif
return pid; /* Parent returns pid */
}
#endif
/*
* ExitPostmaster -- cleanup
*
* Do NOT call exit() directly --- always go through here!
*/
static void
ExitPostmaster(int status)
{
/* should cleanup shared memory and kill all backends */
/*
* Not sure of the semantics here. When the Postmaster dies, should
* the backends all be killed? probably not.
*
* MUST -- vadim 05-10-1999
*/
/* Should I use true instead? */
ClosePostmasterPorts(false);
proc_exit(status);
}
/*
* sigusr1_handler - handle signal conditions from child processes
*/
static void
sigusr1_handler(SIGNAL_ARGS)
{
int save_errno = errno;
PG_SETMASK(&BlockSig);
if (CheckPostmasterSignal(PMSIGNAL_DO_CHECKPOINT))
{
if (CheckPointWarning != 0)
{
/*
* This only times checkpoints forced by running out of
* segment files. Other checkpoints could reduce the
* frequency of forced checkpoints.
*/
time_t now = time(NULL);
if (LastSignalledCheckpoint != 0)
{
int elapsed_secs = now - LastSignalledCheckpoint;
if (elapsed_secs < CheckPointWarning)
ereport(LOG,
(errmsg("checkpoints are occurring too frequently (%d seconds apart)",
elapsed_secs),
errhint("Consider increasing the configuration parameter \"checkpoint_segments\".")));
}
LastSignalledCheckpoint = now;
}
/*
* Request to schedule a checkpoint
*
* Ignore request if checkpoint is already running or checkpointing
* is currently disabled
*/
if (CheckPointPID == 0 && checkpointed &&
StartupPID == 0 && Shutdown == NoShutdown &&
!FatalError && random_seed != 0)
{
CheckPointPID = CheckPointDataBase();
/* note: if fork fails, CheckPointPID stays 0; nothing happens */
}
}
if (CheckPostmasterSignal(PMSIGNAL_PASSWORD_CHANGE))
{
/*
* Password or group file has changed.
*/
load_user();
load_group();
}
if (CheckPostmasterSignal(PMSIGNAL_WAKEN_CHILDREN))
{
/*
* Send SIGUSR2 to all children (triggers AsyncNotifyHandler). See
* storage/ipc/sinvaladt.c for the use of this.
*/
if (Shutdown == NoShutdown)
SignalChildren(SIGUSR2);
}
PG_SETMASK(&UnBlockSig);
errno = save_errno;
}
/*
* Dummy signal handler
*
* We use this for signals that we don't actually use in the postmaster,
* but we do use in backends. If we SIG_IGN such signals in the postmaster,
* then a newly started backend might drop a signal that arrives before it's
* able to reconfigure its signal processing. (See notes in postgres.c.)
*/
static void
dummy_handler(SIGNAL_ARGS)
{
}
/*
* CharRemap: given an int in range 0..61, produce textual encoding of it
* per crypt(3) conventions.
*/
static char
CharRemap(long ch)
{
if (ch < 0)
ch = -ch;
ch = ch % 62;
if (ch < 26)
return 'A' + ch;
ch -= 26;
if (ch < 26)
return 'a' + ch;
ch -= 26;
return '0' + ch;
}
/*
* RandomSalt
*/
static void
RandomSalt(char *cryptSalt, char *md5Salt)
{
long rand = PostmasterRandom();
cryptSalt[0] = CharRemap(rand % 62);
cryptSalt[1] = CharRemap(rand / 62);
/*
* It's okay to reuse the first random value for one of the MD5 salt
* bytes, since only one of the two salts will be sent to the client.
* After that we need to compute more random bits.
*
* We use % 255, sacrificing one possible byte value, so as to ensure
* that all bits of the random() value participate in the result.
* While at it, add one to avoid generating any null bytes.
*/
md5Salt[0] = (rand % 255) + 1;
rand = PostmasterRandom();
md5Salt[1] = (rand % 255) + 1;
rand = PostmasterRandom();
md5Salt[2] = (rand % 255) + 1;
rand = PostmasterRandom();
md5Salt[3] = (rand % 255) + 1;
}
/*
* PostmasterRandom
*/
static long
PostmasterRandom(void)
{
static bool initialized = false;
if (!initialized)
{
Assert(random_seed != 0);
srandom(random_seed);
initialized = true;
}
return random();
}
/*
* Count up number of child processes.
*/
static int
CountChildren(void)
{
Dlelem *curr;
Backend *bp;
int cnt = 0;
for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
{
bp = (Backend *) DLE_VAL(curr);
if (bp->pid != MyProcPid)
cnt++;
}
/* Checkpoint and bgwriter will be in the list, discount them */
if (CheckPointPID != 0)
cnt--;
if (BgWriterPID != 0)
cnt--;
return cnt;
}
/*
* Fire off a subprocess for startup/shutdown/checkpoint/bgwriter.
*
* Return value of SSDataBase is subprocess' PID, or 0 if failed to start subprocess
* (0 is returned only for checkpoint/bgwriter cases).
*
* note: in the EXEC_BACKEND case, we delay the fork until argument list has been
* established
*/
NON_EXEC_STATIC void
SSDataBaseInit(int xlop)
{
const char *statmsg;
IsUnderPostmaster = true; /* we are a postmaster subprocess
* now */
#ifdef EXEC_BACKEND
/* In EXEC case we will not have inherited these settings */
IsPostmasterEnvironment = true;
whereToSendOutput = None;
#endif
MyProcPid = getpid(); /* reset MyProcPid */
/* Lose the postmaster's on-exit routines and port connections */
on_exit_reset();
/*
* Identify myself via ps
*/
switch (xlop)
{
case BS_XLOG_STARTUP:
statmsg = "startup subprocess";
break;
case BS_XLOG_CHECKPOINT:
statmsg = "checkpoint subprocess";
break;
case BS_XLOG_BGWRITER:
statmsg = "bgwriter subprocess";
break;
case BS_XLOG_SHUTDOWN:
statmsg = "shutdown subprocess";
break;
default:
statmsg = "??? subprocess";
break;
}
init_ps_display(statmsg, "", "");
set_ps_display("");
}
static pid_t
SSDataBase(int xlop)
{
pid_t pid;
Backend *bn;
#ifndef EXEC_BACKEND
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
#else
char idbuf[32];
char ddirbuf[MAXPGPATH];
#endif
fflush(stdout);
fflush(stderr);
#ifndef EXEC_BACKEND
#ifdef LINUX_PROFILE
/* see comments in BackendRun */
getitimer(ITIMER_PROF, &prof_itimer);
#endif
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_before_backend_startup();
#endif
/* Non EXEC_BACKEND case; fork here */
if ((pid = fork()) == 0) /* child */
#endif
{
char *av[10];
int ac = 0;
char nbbuf[32];
char xlbuf[32];
#ifndef EXEC_BACKEND
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
#ifdef __BEOS__
/* Specific beos actions after backend startup */
beos_backend_startup();
#endif
/* Close the postmaster's sockets */
ClosePostmasterPorts(true);
SSDataBaseInit(xlop);
#else
if (!write_backend_variables(NULL))
return -1; /* log issued by write_backend_variables */
#endif
/* Set up command-line arguments for subprocess */
av[ac++] = "postgres";
#ifdef EXEC_BACKEND
av[ac++] = "-boot";
#endif
snprintf(nbbuf, sizeof(nbbuf), "-B%d", NBuffers);
av[ac++] = nbbuf;
snprintf(xlbuf, sizeof(xlbuf), "-x%d", xlop);
av[ac++] = xlbuf;
#ifdef EXEC_BACKEND
/* pass data dir before end of secure switches (-p) */
snprintf(ddirbuf, MAXPGPATH, "\"%s\"", DataDir);
av[ac++] = "-D";
av[ac++] = ddirbuf;
/* and the backend identifier + dbname */
snprintf(idbuf, sizeof(idbuf), "-p%lu,template1", tmpBackendFileNum);
av[ac++] = idbuf;
#else
av[ac++] = "-p";
av[ac++] = "template1";
#endif
av[ac] = NULL;
Assert(ac < lengthof(av));
#ifdef EXEC_BACKEND
/* EXEC_BACKEND case; fork/exec here */
#ifdef WIN32
pid = win32_forkexec(postgres_exec_path, av); /* logs on error */
#else
if ((pid = fork()) == 0 && (execv(postgres_exec_path, av) == -1))
{
/* in child */
elog(ERROR, "unable to execv in SSDataBase: %m");
exit(0);
}
#endif
#else
BootstrapMain(ac, av);
ExitPostmaster(0);
#endif
}
/* in parent */
if (pid < 0)
{
#ifndef EXEC_BACKEND
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_backend_startup_failed();
#endif
#endif
switch (xlop)
{
case BS_XLOG_STARTUP:
ereport(LOG,
(errmsg("could not fork startup process: %m")));
break;
case BS_XLOG_CHECKPOINT:
ereport(LOG,
(errmsg("could not fork checkpoint process: %m")));
break;
case BS_XLOG_BGWRITER:
ereport(LOG,
(errmsg("could not fork bgwriter process: %m")));
break;
case BS_XLOG_SHUTDOWN:
ereport(LOG,
(errmsg("could not fork shutdown process: %m")));
break;
default:
ereport(LOG,
(errmsg("could not fork process: %m")));
break;
}
/*
* fork failure is fatal during startup/shutdown, but there's no
* need to choke if a routine checkpoint or starting a background
* writer fails.
*/
if (xlop == BS_XLOG_CHECKPOINT)
return 0;
if (xlop == BS_XLOG_BGWRITER)
return 0;
ExitPostmaster(1);
}
/*
* The startup and shutdown processes are not considered normal
* backends, but the checkpoint and bgwriter processes are.
* They must be added to the list of backends.
*/
if (xlop == BS_XLOG_CHECKPOINT || xlop == BS_XLOG_BGWRITER)
{
if (!(bn = (Backend *) malloc(sizeof(Backend))))
{
ereport(LOG,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
ExitPostmaster(1);
}
bn->pid = pid;
bn->cancel_key = PostmasterRandom();
#ifdef EXEC_BACKEND
ShmemBackendArrayAdd(bn);
#endif
DLAddHead(BackendList, DLNewElem(bn));
/*
* Since this code is executed periodically, it's a fine place to
* do other actions that should happen every now and then on no
* particular schedule. Such as...
*/
TouchSocketFile();
TouchSocketLockFile();
}
return pid;
}
/*
* Create the opts file
*/
static bool
CreateOptsFile(int argc, char *argv[], char *fullprogname)
{
char filename[MAXPGPATH];
FILE *fp;
int i;
snprintf(filename, sizeof(filename), "%s/postmaster.opts", DataDir);
if ((fp = fopen(filename, "w")) == NULL)
{
elog(LOG, "could not create file \"%s\": %m", filename);
return false;
}
fprintf(fp, "%s", fullprogname);
for (i = 1; i < argc; i++)
fprintf(fp, " '%s'", argv[i]);
fputs("\n", fp);
if (fclose(fp))
{
elog(LOG, "could not write file \"%s\": %m", filename);
return false;
}
return true;
}
/*
* This should be used only for reporting "interactive" errors (essentially,
* bogus arguments on the command line). Once the postmaster is launched,
* use ereport. In particular, don't use this for anything that occurs
* after pmdaemonize.
*/
static void
postmaster_error(const char *fmt,...)
{
va_list ap;
fprintf(stderr, "%s: ", progname);
va_start(ap, fmt);
vfprintf(stderr, gettext(fmt), ap);
va_end(ap);
fprintf(stderr, "\n");
}
#ifdef EXEC_BACKEND
/*
* The following need to be available to the read/write_backend_variables
* functions
*/
#include "storage/spin.h"
extern XLogRecPtr RedoRecPtr;
extern XLogwrtResult LogwrtResult;
extern slock_t *ShmemLock;
extern slock_t *ShmemIndexLock;
extern void *ShmemIndexAlloc;
typedef struct LWLock LWLock;
extern LWLock *LWLockArray;
extern slock_t *ProcStructLock;
extern int pgStatSock;
#define write_var(var,fp) fwrite((void*)&(var),sizeof(var),1,fp)
#define read_var(var,fp) fread((void*)&(var),sizeof(var),1,fp)
#define get_tmp_backend_file_name(buf,id) \
do { \
Assert(DataDir); \
sprintf((buf), \
"%s/%s/%s.backend_var.%lu", \
DataDir, \
PG_TEMP_FILES_DIR, \
PG_TEMP_FILE_PREFIX, \
(id)); \
} while (0)
static bool
write_backend_variables(Port *port)
{
char filename[MAXPGPATH];
FILE *fp;
get_tmp_backend_file_name(filename,++tmpBackendFileNum);
/* Open file */
fp = AllocateFile(filename, PG_BINARY_W);
if (!fp)
{
/* As per OpenTemporaryFile... */
char dirname[MAXPGPATH];
sprintf(dirname,"%s/%s",DataDir,PG_TEMP_FILES_DIR);
mkdir(dirname, S_IRWXU);
fp = AllocateFile(filename, PG_BINARY_W);
if (!fp)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m", filename)));
return false;
}
}
/* Write vars */
if (port)
{
write_var(port->sock,fp);
write_var(port->proto,fp);
write_var(port->laddr,fp);
write_var(port->raddr,fp);
write_var(port->canAcceptConnections,fp);
write_var(port->cryptSalt,fp);
write_var(port->md5Salt,fp);
}
write_var(MyCancelKey,fp);
write_var(RedoRecPtr,fp);
write_var(LogwrtResult,fp);
write_var(UsedShmemSegID,fp);
write_var(UsedShmemSegAddr,fp);
write_var(ShmemLock,fp);
write_var(ShmemIndexLock,fp);
write_var(ShmemVariableCache,fp);
write_var(ShmemIndexAlloc,fp);
write_var(ShmemBackendArray,fp);
write_var(LWLockArray,fp);
write_var(ProcStructLock,fp);
write_var(pgStatSock,fp);
write_var(PreAuthDelay,fp);
write_var(debug_flag,fp);
write_var(PostmasterPid,fp);
fwrite((void *)my_exec_path, MAXPGPATH, 1, fp);
/* Release file */
if (FreeFile(fp))
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m", filename)));
return false;
}
return true;
}
void
read_backend_variables(unsigned long id, Port *port)
{
char filename[MAXPGPATH];
FILE *fp;
get_tmp_backend_file_name(filename,id);
/* Open file */
fp = AllocateFile(filename, PG_BINARY_R);
if (!fp)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read from backend_variables file \"%s\": %m", filename)));
return;
}
/* Read vars */
if (port)
{
read_var(port->sock,fp);
read_var(port->proto,fp);
read_var(port->laddr,fp);
read_var(port->raddr,fp);
read_var(port->canAcceptConnections,fp);
read_var(port->cryptSalt,fp);
read_var(port->md5Salt,fp);
}
read_var(MyCancelKey,fp);
read_var(RedoRecPtr,fp);
read_var(LogwrtResult,fp);
read_var(UsedShmemSegID,fp);
read_var(UsedShmemSegAddr,fp);
read_var(ShmemLock,fp);
read_var(ShmemIndexLock,fp);
read_var(ShmemVariableCache,fp);
read_var(ShmemIndexAlloc,fp);
read_var(ShmemBackendArray,fp);
read_var(LWLockArray,fp);
read_var(ProcStructLock,fp);
read_var(pgStatSock,fp);
read_var(PreAuthDelay,fp);
read_var(debug_flag,fp);
read_var(PostmasterPid,fp);
fread((void *)my_exec_path, MAXPGPATH, 1, fp);
/* Release file */
FreeFile(fp);
if (unlink(filename) != 0)
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m", filename)));
}
size_t ShmemBackendArraySize(void)
{
return (NUM_BACKENDARRAY_ELEMS*sizeof(Backend));
}
void ShmemBackendArrayAllocation(void)
{
size_t size = ShmemBackendArraySize();
ShmemBackendArray = (Backend*)ShmemAlloc(size);
memset(ShmemBackendArray, 0, size);
}
static void ShmemBackendArrayAdd(Backend *bn)
{
int i;
for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
{
/* Find an empty slot */
if (ShmemBackendArray[i].pid == 0)
{
ShmemBackendArray[i] = *bn;
return;
}
}
ereport(FATAL,
(errmsg_internal("unable to add backend entry")));
}
static void ShmemBackendArrayRemove(pid_t pid)
{
int i;
for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
{
if (ShmemBackendArray[i].pid == pid)
{
/* Mark the slot as empty */
ShmemBackendArray[i].pid = 0;
return;
}
}
ereport(WARNING,
(errmsg_internal("unable to find backend entry with pid %d",
pid)));
}
#endif
#ifdef WIN32
pid_t win32_forkexec(const char* path, char *argv[])
{
STARTUPINFO si;
PROCESS_INFORMATION pi;
char *p;
int i;
char cmdLine[MAXPGPATH];
HANDLE childHandleCopy;
HANDLE waiterThread;
/* Format the cmd line */
snprintf(cmdLine,sizeof(cmdLine),"\"%s\"",path);
i = 0;
while (argv[++i] != NULL)
{
/* FIXME: [fork/exec] some strlen checks might be prudent here */
strcat(cmdLine," ");
strcat(cmdLine,argv[i]);
}
/*
* The following snippet can disappear when we consistently
* use forward slashes.
*/
p = cmdLine;
while (*(p++) != '\0')
if (*p == '/') *p = '\\';
memset(&pi,0,sizeof(pi));
memset(&si,0,sizeof(si));
si.cb = sizeof(si);
if (!CreateProcess(NULL,cmdLine,NULL,NULL,TRUE,0,NULL,NULL,&si,&pi))
{
elog(ERROR,"CreateProcess call failed (%i): %m",(int)GetLastError());
return -1;
}
if (!IsUnderPostmaster)
/* We are the Postmaster creating a child... */
win32_AddChild(pi.dwProcessId,pi.hProcess);
if (!DuplicateHandle(GetCurrentProcess(),
pi.hProcess,
GetCurrentProcess(),
&childHandleCopy,
0,
FALSE,
DUPLICATE_SAME_ACCESS))
ereport(FATAL,
(errmsg_internal("failed to duplicate child handle: %i",(int)GetLastError())));
waiterThread = CreateThread(NULL, 64*1024, win32_sigchld_waiter, (LPVOID)childHandleCopy, 0, NULL);
if (!waiterThread)
ereport(FATAL,
(errmsg_internal("failed to create sigchld waiter thread: %i",(int)GetLastError())));
CloseHandle(waiterThread);
if (IsUnderPostmaster)
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
return pi.dwProcessId;
}
/*
* Note: The following three functions must not be interrupted (eg. by signals).
* As the Postgres Win32 signalling architecture (currently) requires polling,
* or APC checking functions which aren't used here, this is not an issue.
*
* We keep two separate arrays, instead of a single array of pid/HANDLE structs,
* to avoid having to re-create a handle array for WaitForMultipleObjects on
* each call to win32_waitpid.
*/
static void win32_AddChild(pid_t pid, HANDLE handle)
{
Assert(win32_childPIDArray && win32_childHNDArray);
if (win32_numChildren < NUM_BACKENDARRAY_ELEMS)
{
win32_childPIDArray[win32_numChildren] = pid;
win32_childHNDArray[win32_numChildren] = handle;
++win32_numChildren;
}
else
ereport(FATAL,
(errmsg_internal("unable to add child entry with pid %lu",
pid)));
}
static void win32_RemoveChild(pid_t pid)
{
int i;
Assert(win32_childPIDArray && win32_childHNDArray);
for (i = 0; i < win32_numChildren; i++)
{
if (win32_childPIDArray[i] == pid)
{
CloseHandle(win32_childHNDArray[i]);
/* Swap last entry into the "removed" one */
--win32_numChildren;
win32_childPIDArray[i] = win32_childPIDArray[win32_numChildren];
win32_childHNDArray[i] = win32_childHNDArray[win32_numChildren];
return;
}
}
ereport(WARNING,
(errmsg_internal("unable to find child entry with pid %lu",
pid)));
}
static pid_t win32_waitpid(int *exitstatus)
{
Assert(win32_childPIDArray && win32_childHNDArray);
elog(DEBUG3,"waiting on %lu children",win32_numChildren);
if (win32_numChildren > 0)
{
/*
* Note: Do NOT use WaitForMultipleObjectsEx, as we don't
* want to run queued APCs here.
*/
int index;
DWORD exitCode;
DWORD ret = WaitForMultipleObjects(win32_numChildren,win32_childHNDArray,FALSE,0);
switch (ret)
{
case WAIT_FAILED:
ereport(ERROR,
(errmsg_internal("failed to wait on %lu children: %i",
win32_numChildren,(int)GetLastError())));
/* Fall through to WAIT_TIMEOUTs return */
case WAIT_TIMEOUT:
/* No children have finished */
return -1;
default:
/* Get the exit code, and return the PID of, the respective process */
index = ret-WAIT_OBJECT_0;
Assert(index >= 0 && index < win32_numChildren);
if (!GetExitCodeProcess(win32_childHNDArray[index],&exitCode))
/*
* If we get this far, this should never happen, but, then again...
* No choice other than to assume a catastrophic failure.
*/
ereport(FATAL,
(errmsg_internal("failed to get exit code for child %lu",
win32_childPIDArray[index])));
*exitstatus = (int)exitCode;
return win32_childPIDArray[index];
}
}
/* No children */
return -1;
}
/* Note! Code belows executes on separate threads, one for
each child process created */
static DWORD WINAPI win32_sigchld_waiter(LPVOID param) {
HANDLE procHandle = (HANDLE)param;
DWORD r = WaitForSingleObject(procHandle, INFINITE);
if (r == WAIT_OBJECT_0)
pg_queue_signal(SIGCHLD);
else
fprintf(stderr,"ERROR: Failed to wait on child process handle: %i\n",(int)GetLastError());
CloseHandle(procHandle);
return 0;
}
#endif