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Code review for postmaster.pid contents changes.

Browse Source 
Fix broken test for pre-existing postmaster, caused by wrong code for
appending lines to the lockfile; don't write a failed listen_address
setting into the lockfile; don't arbitrarily change the location of the
data directory in the lockfile compared to previous releases; provide more
consistent and useful definitions of the socket path and listen_address
entries; avoid assuming that pg_ctl has the same DEFAULT_PGSOCKET_DIR as
the postmaster; assorted code style improvements.
This commit is contained in:
Tom Lane 2011-01-13 19:01:28 -05:00
parent f0f36045b2
commit 52948169bc
7 changed files with 198 additions and 163 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
doc/src/sgml/storage.sgml
View File

@ -117,9 +117,14 @@ last started with</entry>
<row>
<entry><filename>postmaster.pid</></entry>
<entry>A lock file recording the current postmaster process id (PID),
postmaster start time, cluster data directory, port number, user-specified
Unix domain socket directory, first valid listen_address host, and
shared memory segment ID</entry>
cluster data directory path,
postmaster start timestamp,
port number,
Unix-domain socket directory path (empty on Windows),
first valid listen_address (IP address or <literal>*</>, or empty if
not listening on TCP),
and shared memory segment ID
(this file is not present after server shutdown)</entry>
</row>
</tbody>

4
src/backend/port/ipc_test.c
View File

@ -104,7 +104,7 @@ on_exit_reset(void)
}
void
AddToLockFile(int target_line, const char *str)
AddToDataDirLockFile(int target_line, const char *str)
{
}
@ -135,7 +135,7 @@ errcode_for_file_access(void)
bool
errstart(int elevel, const char *filename, int lineno,
const char *funcname)
const char *funcname, const char *domain)
{
return (elevel >= ERROR);
}

13
src/backend/port/sysv_shmem.c
View File

@ -199,15 +199,16 @@ InternalIpcMemoryCreate(IpcMemoryKey memKey, Size size)
on_shmem_exit(IpcMemoryDetach, PointerGetDatum(memAddress));
/*
* Append record key and ID in lockfile for data directory. Format
* to try to keep it the same length.
* Store shmem key and ID in data directory lockfile. Format to try to
* keep it the same length always (trailing junk in the lockfile won't
* hurt, but might confuse humans).
*/
{
char line[32];
char line[64];
sprintf(line, "%9lu %9lu\n", (unsigned long) memKey,
(unsigned long) shmid);
AddToLockFile(LOCK_FILE_LINES, line);
sprintf(line, "%9lu %9lu",
(unsigned long) memKey, (unsigned long) shmid);
AddToDataDirLockFile(LOCK_FILE_LINE_SHMEM_KEY, line);
}
return memAddress;

35
src/backend/postmaster/postmaster.c
View File

@ -482,9 +482,9 @@ PostmasterMain(int argc, char *argv[])
int opt;
int status;
char *userDoption = NULL;
bool listen_addr_saved = false;
int i;
bool connection_line_output = false;
MyProcPid = PostmasterPid = getpid();
MyStartTime = time(NULL);
@ -861,24 +861,21 @@ PostmasterMain(int argc, char *argv[])
UnixSocketDir,
ListenSocket, MAXLISTEN);
else
{
status = StreamServerPort(AF_UNSPEC, curhost,
(unsigned short) PostPortNumber,
UnixSocketDir,
ListenSocket, MAXLISTEN);
/* must supply a valid listen_address for PQping() */
if (!connection_line_output)
{
char line[MAXPGPATH + 2];
sprintf(line, "%s\n", curhost);
AddToLockFile(LOCK_FILE_LINES - 1, line);
connection_line_output = true;
if (status == STATUS_OK)
{
success++;
/* record the first successful host addr in lockfile */
if (!listen_addr_saved)
{
AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, curhost);
listen_addr_saved = true;
}
}
if (status == STATUS_OK)
success++;
else
ereport(WARNING,
(errmsg("could not create listen socket for \"%s\"",
@ -893,10 +890,6 @@ PostmasterMain(int argc, char *argv[])
pfree(rawstring);
}
/* Supply an empty listen_address line for PQping() */
if (!connection_line_output)
AddToLockFile(LOCK_FILE_LINES - 1, "\n");
#ifdef USE_BONJOUR
/* Register for Bonjour only if we opened TCP socket(s) */
if (enable_bonjour && ListenSocket[0] != PGINVALID_SOCKET)
@ -952,6 +945,14 @@ PostmasterMain(int argc, char *argv[])
ereport(FATAL,
(errmsg("no socket created for listening")));
/*
* If no valid TCP ports, write an empty line for listen address,
* indicating the Unix socket must be used. Note that this line is not
* added to the lock file until there is a socket backing it.
*/
if (!listen_addr_saved)
AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, "");
/*
* Set up shared memory and semaphores.
*/

77
src/backend/utils/init/miscinit.c
View File

@ -46,20 +46,7 @@
#define DIRECTORY_LOCK_FILE "postmaster.pid"
/*
* The lock file contents are:
*
* line #
* 1 pid
* 2 postmaster start time
* 3 data directory
* 4 port #
* 5 user-specified socket directory
* (the lines below are added later)
* 6 first valid listen_address
* 7 shared memory key
*/
ProcessingMode Mode = InitProcessing;
/* Note: we rely on this to initialize as zeroes */
@ -244,7 +231,6 @@ static int SecurityRestrictionContext = 0;
static bool SetRoleIsActive = false;
/*
* GetUserId - get the current effective user ID.
*
@ -691,7 +677,7 @@ CreateLockFile(const char *filename, bool amPostmaster,
bool isDDLock, const char *refName)
{
int fd;
char buffer[MAXPGPATH * 3 + 256];
char buffer[MAXPGPATH * 2 + 256];
int ntries;
int len;
int encoded_pid;
@ -852,26 +838,26 @@ CreateLockFile(const char *filename, bool amPostmaster,
* looking to see if there is an associated shmem segment that is
* still in use.
*
* Note: because postmaster.pid is written in two steps, we might not
* find the shmem ID values in it; we can't treat that as an error.
* Note: because postmaster.pid is written in multiple steps, we might
* not find the shmem ID values in it; we can't treat that as an
* error.
*/
if (isDDLock)
{
char *ptr = buffer;
unsigned long id1, id2;
int lineno;
unsigned long id1,
id2;
int lineno;
for (lineno = 1; lineno <= LOCK_FILE_LINES - 1; lineno++)
for (lineno = 1; lineno < LOCK_FILE_LINE_SHMEM_KEY; lineno++)
{
if ((ptr = strchr(ptr, '\n')) == NULL)
{
elog(LOG, "bogus data in \"%s\"", DIRECTORY_LOCK_FILE);
break;
}
ptr++;
}
if (ptr && sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
if (ptr != NULL &&
sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
{
if (PGSharedMemoryIsInUse(id1, id2))
ereport(FATAL,
@ -903,12 +889,23 @@ CreateLockFile(const char *filename, bool amPostmaster,
}
/*
* Successfully created the file, now fill it.
* Successfully created the file, now fill it. See comment in miscadmin.h
* about the contents. Note that we write the same info into both datadir
* and socket lockfiles; although more stuff may get added to the datadir
* lockfile later.
*/
snprintf(buffer, sizeof(buffer), "%d\n%ld\n%s\n%d\n%s\n",
snprintf(buffer, sizeof(buffer), "%d\n%s\n%ld\n%d\n%s\n",
amPostmaster ? (int) my_pid : -((int) my_pid),
(long) MyStartTime, DataDir, PostPortNumber,
UnixSocketDir);
DataDir,
(long) MyStartTime,
PostPortNumber,
#ifdef HAVE_UNIX_SOCKETS
(*UnixSocketDir != '\0') ? UnixSocketDir : DEFAULT_PGSOCKET_DIR
#else
""
#endif
);
errno = 0;
if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
{
@ -1019,17 +1016,20 @@ TouchSocketLockFile(void)
/*
* Add lines to the data directory lock file. This erases all following
* lines, but that is OK because lines are added in order.
* Add (or replace) a line in the data directory lock file.
* The given string should not include a trailing newline.
*
* Caution: this erases all following lines. In current usage that is OK
* because lines are added in order. We could improve it if needed.
*/
void
AddToLockFile(int target_line, const char *str)
AddToDataDirLockFile(int target_line, const char *str)
{
int fd;
int len;
int lineno;
char *ptr;
char buffer[MAXPGPATH * 3 + 256];
char buffer[BLCKSZ];
fd = open(DIRECTORY_LOCK_FILE, O_RDWR | PG_BINARY, 0);
if (fd < 0)
@ -1040,7 +1040,7 @@ AddToLockFile(int target_line, const char *str)
DIRECTORY_LOCK_FILE)));
return;
}
len = read(fd, buffer, sizeof(buffer) - 100);
len = read(fd, buffer, sizeof(buffer) - 1);
if (len < 0)
{
ereport(LOG,
@ -1053,7 +1053,7 @@ AddToLockFile(int target_line, const char *str)
buffer[len] = '\0';
/*
* Skip over first four lines (PID, pgdata, portnum, socketdir).
* Skip over lines we are not supposed to rewrite.
*/
ptr = buffer;
for (lineno = 1; lineno < target_line; lineno++)
@ -1066,8 +1066,11 @@ AddToLockFile(int target_line, const char *str)
}
ptr++;
}
strlcat(buffer, str, sizeof(buffer));
/*
* Write or rewrite the target line.
*/
snprintf(ptr, buffer + sizeof(buffer) - ptr, "%s\n", str);
/*
* And rewrite the data. Since we write in a single kernel call, this

193
src/bin/pg_ctl/pg_ctl.c
View File

@ -22,7 +22,6 @@
#include <locale.h>
#include <signal.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
@ -91,6 +90,24 @@ static char *register_username = NULL;
static char *register_password = NULL;
static char *argv0 = NULL;
static bool allow_core_files = false;
static time_t start_time;
static char postopts_file[MAXPGPATH];
static char pid_file[MAXPGPATH];
static char backup_file[MAXPGPATH];
static char recovery_file[MAXPGPATH];
#if defined(WIN32) || defined(__CYGWIN__)
static DWORD pgctl_start_type = SERVICE_AUTO_START;
static SERVICE_STATUS status;
static SERVICE_STATUS_HANDLE hStatus = (SERVICE_STATUS_HANDLE) 0;
static HANDLE shutdownHandles[2];
static pid_t postmasterPID = -1;
#define shutdownEvent shutdownHandles[0]
#define postmasterProcess shutdownHandles[1]
#endif
static void
write_stderr(const char *fmt,...)
@ -122,15 +139,6 @@ static void WINAPI pgwin32_ServiceHandler(DWORD);
static void WINAPI pgwin32_ServiceMain(DWORD, LPTSTR *);
static void pgwin32_doRunAsService(void);
static int CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_service);
static DWORD pgctl_start_type = SERVICE_AUTO_START;
static SERVICE_STATUS status;
static SERVICE_STATUS_HANDLE hStatus = (SERVICE_STATUS_HANDLE) 0;
static HANDLE shutdownHandles[2];
static pid_t postmasterPID = -1;
#define shutdownEvent shutdownHandles[0]
#define postmasterProcess shutdownHandles[1]
#endif
static pgpid_t get_pgpid(void);
@ -140,12 +148,6 @@ static void read_post_opts(void);
static PGPing test_postmaster_connection(bool);
static bool postmaster_is_alive(pid_t pid);
static time_t start_time;
static char postopts_file[MAXPGPATH];
static char pid_file[MAXPGPATH];
static char backup_file[MAXPGPATH];
static char recovery_file[MAXPGPATH];
#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_CORE)
static void unlimit_core_size(void);
@ -406,14 +408,10 @@ start_postmaster(void)
static PGPing
test_postmaster_connection(bool do_checkpoint)
{
int portnum = 0;
char host_str[MAXPGPATH];
char connstr[MAXPGPATH + 256];
PGPing ret = PQPING_OK; /* assume success for wait == zero */
char **optlines;
char connstr[MAXPGPATH * 2 + 256];
int i;
host_str[0] = '\0';
connstr[0] = '\0';
for (i = 0; i < wait_seconds; i++)
@ -421,108 +419,111 @@ test_postmaster_connection(bool do_checkpoint)
/* Do we need a connection string? */
if (connstr[0] == '\0')
{
/*
* The number of lines in postmaster.pid tells us several things:
/*----------
* The number of lines in postmaster.pid tells us several things:
*
* # of lines
* # of lines
* 0 lock file created but status not written
* 2 pre-9.1 server, shared memory not created
* 3 pre-9.1 server, shared memory created
* 5 9.1+ server, listen host not created
* 5 9.1+ server, ports not opened
* 6 9.1+ server, shared memory not created
* 7 9.1+ server, shared memory created
*
* For pre-9.1 Unix servers, we grab the port number from the
* shmem key (first value on line 3). Pre-9.1 Win32 has no
* written shmem key, so we fail. 9.1+ writes connection
* information in the file for us to use.
* (PG_VERSION could also have told us the major version.)
* This code does not support pre-9.1 servers. On Unix machines
* we could consider extracting the port number from the shmem
* key, but that (a) is not robust, and (b) doesn't help with
* finding out the socket directory. And it wouldn't work anyway
* on Windows.
*
* If we see less than 6 lines in postmaster.pid, just keep
* waiting.
*----------
*/
/* Try to read a completed postmaster.pid file */
char **optlines;
/* Try to read the postmaster.pid file */
if ((optlines = readfile(pid_file)) != NULL &&
optlines[0] != NULL &&
optlines[1] != NULL &&
optlines[2] != NULL &&
/* pre-9.1 server or listen_address line is present? */
(optlines[3] == NULL ||
optlines[5] != NULL))
{
/* A 3-line file? */
optlines[2] != NULL)
{
if (optlines[3] == NULL)
{
/*
* Pre-9.1: on Unix, we get the port number by
* deriving it from the shmem key (the first number on
* on the line); see
* miscinit.c::RecordSharedMemoryInLockFile().
*/
portnum = atoi(optlines[2]) / 1000;
/* Win32 does not give us a shmem key, so we fail. */
if (portnum == 0)
{
write_stderr(_("%s: -w option is not supported on this platform\nwhen connecting to a pre-9.1 server\n"),
progname);
return PQPING_NO_ATTEMPT;
}
/* File is exactly three lines, must be pre-9.1 */
write_stderr(_("%s: -w option is not supported when starting a pre-9.1 server\n"),
progname);
return PQPING_NO_ATTEMPT;
}
else
else if (optlines[4] != NULL &&
optlines[5] != NULL)
{
/*
* Easy check to see if we are looking at the right
* data directory: Is the postmaster older than this
* execution of pg_ctl? Subtract 2 seconds to account
* for possible clock skew between pg_ctl and the
* postmaster.
*/
if (atol(optlines[1]) < start_time - 2)
{
write_stderr(_("%s: this data directory is running an older postmaster\n"),
progname);
return PQPING_NO_ATTEMPT;
}
portnum = atoi(optlines[3]);
/* File is complete enough for us, parse it */
time_t pmstart;
int portnum;
char *sockdir;
char *hostaddr;
char host_str[MAXPGPATH];
/*
* Determine the proper host string to use.
* Easy cross-check that we are looking at the right data
* directory: is the postmaster older than this execution
* of pg_ctl? Subtract 2 seconds to allow for possible
* clock skew between pg_ctl and the postmaster.
*/
#ifdef HAVE_UNIX_SOCKETS
pmstart = atol(optlines[LOCK_FILE_LINE_START_TIME - 1]);
if (pmstart < start_time - 2)
{
write_stderr(_("%s: this data directory is running a pre-existing postmaster\n"),
progname);
return PQPING_NO_ATTEMPT;
}
/*
* Use socket directory, if specified. We assume if we
* have unix sockets, the server does too because we
* just started the postmaster.
* OK, extract port number and host string to use.
* Prefer using Unix socket if available.
*/
portnum = atoi(optlines[LOCK_FILE_LINE_PORT - 1]);
sockdir = optlines[LOCK_FILE_LINE_SOCKET_DIR - 1];
hostaddr = optlines[LOCK_FILE_LINE_LISTEN_ADDR - 1];
/*
* While unix_socket_directory can accept relative
* directories, libpq's host must have a leading slash
* to indicate a socket directory.
* While unix_socket_directory can accept relative
* directories, libpq's host parameter must have a leading
* slash to indicate a socket directory. So, ignore
* sockdir if it's relative, and try to use TCP instead.
*/
if (optlines[4][0] != '\n' && optlines[4][0] != '/')
if (sockdir[0] == '/')
strlcpy(host_str, sockdir, sizeof(host_str));
else
strlcpy(host_str, hostaddr, sizeof(host_str));
/* remove trailing newline */
if (strchr(host_str, '\n') != NULL)
*strchr(host_str, '\n') = '\0';
/* Fail if we couldn't get either sockdir or host addr */
if (host_str[0] == '\0')
{
write_stderr(_("%s: -w option cannot use a relative socket directory specification\n"),
progname);
return PQPING_NO_ATTEMPT;
}
strlcpy(host_str, optlines[4], sizeof(host_str));
#else
strlcpy(host_str, optlines[5], sizeof(host_str));
#endif
/* remove newline */
if (strchr(host_str, '\n') != NULL)
*strchr(host_str, '\n') = '\0';
}
/*
* We need to set connect_timeout otherwise on Windows the
* Service Control Manager (SCM) will probably timeout first.
*/
snprintf(connstr, sizeof(connstr),
"dbname=postgres port=%d connect_timeout=5", portnum);
if (host_str[0] != '\0')
snprintf(connstr + strlen(connstr), sizeof(connstr) - strlen(connstr),
" host='%s'", host_str);
/* If postmaster is listening on "*", use "localhost" */
if (strcmp(host_str, "*") == 0)
strcpy(host_str, "localhost");
/*
* We need to set connect_timeout otherwise on Windows the
* Service Control Manager (SCM) will probably timeout
* first.
*/
snprintf(connstr, sizeof(connstr),
"dbname=postgres port=%d host='%s' connect_timeout=5",
portnum, host_str);
}
}
}
@ -544,7 +545,7 @@ test_postmaster_connection(bool do_checkpoint)
* startup time is changing, otherwise it'll usually send a
* stop signal after 20 seconds, despite incrementing the
* checkpoint counter.
*/
*/
status.dwWaitHint += 6000;
status.dwCheckPoint++;
SetServiceStatus(hStatus, (LPSERVICE_STATUS) &status);

28
src/include/miscadmin.h
View File

@ -348,11 +348,35 @@ extern PGDLLIMPORT bool process_shared_preload_libraries_in_progress;
extern char *shared_preload_libraries_string;
extern char *local_preload_libraries_string;
#define LOCK_FILE_LINES 7
/*
* As of 9.1, the contents of the data-directory lock file are:
*
* line #
* 1 postmaster PID (or negative of a standalone backend's PID)
* 2 data directory path
* 3 postmaster start timestamp (time_t representation)
* 4 port number
* 5 socket directory path (empty on Windows)
* 6 first listen_address (IP address or "*"; empty if no TCP port)
* 7 shared memory key (not present on Windows)
*
* Lines 6 and up are added via AddToDataDirLockFile() after initial file
* creation; they have to be ordered according to time of addition.
*
* The socket lock file, if used, has the same contents as lines 1-5.
*/
#define LOCK_FILE_LINE_PID 1
#define LOCK_FILE_LINE_DATA_DIR 2
#define LOCK_FILE_LINE_START_TIME 3
#define LOCK_FILE_LINE_PORT 4
#define LOCK_FILE_LINE_SOCKET_DIR 5
#define LOCK_FILE_LINE_LISTEN_ADDR 6
#define LOCK_FILE_LINE_SHMEM_KEY 7
extern void CreateDataDirLockFile(bool amPostmaster);
extern void CreateSocketLockFile(const char *socketfile, bool amPostmaster);
extern void TouchSocketLockFile(void);
extern void AddToLockFile(int target_line, const char *str);
extern void AddToDataDirLockFile(int target_line, const char *str);
extern void ValidatePgVersion(const char *path);
extern void process_shared_preload_libraries(void);
extern void process_local_preload_libraries(void);