@ -49,8 +49,8 @@
ProcessingMode Mode = InitProcessing ;
/* Note: we rely on this to initialize as zeroes */
static char socketLockFile [ MAXPGPATH ] ;
/* List of lock files to be removed at proc exit */
static List * lock_files = NIL ;
/* ----------------------------------------------------------------
@ -628,7 +628,7 @@ GetUserNameFromId(Oid roleid)
* Interlock - file support
*
* These routines are used to create both a data - directory lockfile
* ( $ DATADIR / postmaster . pid ) and a Unix - socket - file lockfile ( $ SOCKFILE . lock ) .
* ( $ DATADIR / postmaster . pid ) and Unix - socket - file lockfiles ( $ SOCKFILE . lock ) .
* Both kinds of files contain the same info initially , although we can add
* more information to a data - directory lockfile after it ' s created , using
* AddToDataDirLockFile ( ) . See miscadmin . h for documentation of the contents
@ -640,32 +640,35 @@ GetUserNameFromId(Oid roleid)
*/
/*
* proc_exit callback to remove a lockfile .
* proc_exit callback to remove lockfiles .
*/
static void
UnlinkLockFile ( int status , Datum filename )
UnlinkLockFiles ( int status , Datum arg )
{
char * fname = ( char * ) DatumGetPointer ( filename ) ;
ListCell * l ;
if ( fname ! = NULL )
foreach ( l , lock_files )
{
if ( unlink ( fname ) ! = 0 )
{
/* Should we complain if the unlink fails? */
}
free ( fname ) ;
char * curfile = ( char * ) lfirst ( l ) ;
unlink ( curfile ) ;
/* Should we complain if the unlink fails? */
}
/* Since we're about to exit, no need to reclaim storage */
lock_files = NIL ;
}
/*
* Create a lockfile .
*
* filename is the name of the lockfile to create .
* filename is the path name of the lockfile to create .
* amPostmaster is used to determine how to encode the output PID .
* socketDir is the Unix socket directory path to include ( possibly empty ) .
* isDDLock and refName are used to determine what error message to produce .
*/
static void
CreateLockFile ( const char * filename , bool amPostmaster ,
const char * socketDir ,
bool isDDLock , const char * refName )
{
int fd ;
@ -891,12 +894,7 @@ CreateLockFile(const char *filename, bool amPostmaster,
DataDir ,
( long ) MyStartTime ,
PostPortNumber ,
# ifdef HAVE_UNIX_SOCKETS
( * UnixSocketDir ! = ' \0 ' ) ? UnixSocketDir : DEFAULT_PGSOCKET_DIR
# else
" "
# endif
) ;
socketDir ) ;
errno = 0 ;
if ( write ( fd , buffer , strlen ( buffer ) ) ! = strlen ( buffer ) )
@ -934,9 +932,14 @@ CreateLockFile(const char *filename, bool amPostmaster,
}
/*
* Arrange for automatic removal of lockfile at proc_exit .
* Arrange to unlink the lock file ( s ) at proc_exit . If this is the
* first one , set up the on_proc_exit function to do it ; then add this
* lock file to the list of files to unlink .
*/
on_proc_exit ( UnlinkLockFile , PointerGetDatum ( strdup ( filename ) ) ) ;
if ( lock_files = = NIL )
on_proc_exit ( UnlinkLockFiles , 0 ) ;
lock_files = lappend ( lock_files , pstrdup ( filename ) ) ;
}
/*
@ -945,41 +948,50 @@ CreateLockFile(const char *filename, bool amPostmaster,
* When this is called , we must have already switched the working
* directory to DataDir , so we can just use a relative path . This
* helps ensure that we are locking the directory we should be .
*
* Note that the socket directory path line is initially written as empty .
* postmaster . c will rewrite it upon creating the first Unix socket .
*/
void
CreateDataDirLockFile ( bool amPostmaster )
{
CreateLockFile ( DIRECTORY_LOCK_FILE , amPostmaster , true , DataDir ) ;
CreateLockFile ( DIRECTORY_LOCK_FILE , amPostmaster , " " , true , DataDir ) ;
}
/*
* Create a lockfile for the specified Unix socket file .
*/
void
CreateSocketLockFile ( const char * socketfile , bool amPostmaster )
CreateSocketLockFile ( const char * socketfile , bool amPostmaster ,
const char * socketDir )
{
char lockfile [ MAXPGPATH ] ;
snprintf ( lockfile , sizeof ( lockfile ) , " %s.lock " , socketfile ) ;
CreateLockFile ( lockfile , amPostmaster , false , socketfile ) ;
/* Save name of lockfile for TouchSocketLockFile */
strcpy ( socketLockFile , lockfile ) ;
CreateLockFile ( lockfile , amPostmaster , socketDir , false , socketfile ) ;
}
/*
* TouchSocketLockFile - - mark socket lock file as recently accessed
* TouchSocketLockFiles - - mark socket lock files as recently accessed
*
* This routine should be called every so often to ensure that the lock file
* has a recent mod or access date . That saves i t
* This routine should be called every so often to ensure that the socket
* lock files have a recent mod or access date . That saves them
* from being removed by overenthusiastic / tmp - directory - cleaner daemons .
* ( Another reason we should never have put the socket file in / tmp . . . )
*/
void
TouchSocketLockFile ( void )
TouchSocketLockFiles ( void )
{
/* Do nothing if we did not create a socket... */
if ( socketLockFile [ 0 ] ! = ' \0 ' )
ListCell * l ;
foreach ( l , lock_files )
{
char * socketLockFile = ( char * ) lfirst ( l ) ;
/* No need to touch the data directory lock file, we trust */
if ( strcmp ( socketLockFile , DIRECTORY_LOCK_FILE ) = = 0 )
continue ;
/*
* utime ( ) is POSIX standard , utimes ( ) is a common alternative ; if we
* have neither , fall back to actually reading the file ( which only
@ -1011,8 +1023,10 @@ TouchSocketLockFile(void)
* 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 .
* Note : because we don ' t truncate the file , if we were to rewrite a line
* with less data than it had before , there would be garbage after the last
* line . We don ' t ever actually do that , so not worth adding another kernel
* call to cover the possibility .
*/
void
AddToDataDirLockFile ( int target_line , const char * str )
@ -1020,8 +1034,10 @@ AddToDataDirLockFile(int target_line, const char *str)
int fd ;
int len ;
int lineno ;
char * ptr ;
char buffer [ BLCKSZ ] ;
char * srcptr ;
char * destptr ;
char srcbuffer [ BLCKSZ ] ;
char destbuffer [ BLCKSZ ] ;
fd = open ( DIRECTORY_LOCK_FILE , O_RDWR | PG_BINARY , 0 ) ;
if ( fd < 0 )
@ -1032,7 +1048,7 @@ AddToDataDirLockFile(int target_line, const char *str)
DIRECTORY_LOCK_FILE ) ) ) ;
return ;
}
len = read ( fd , buffer , sizeof ( buffer ) - 1 ) ;
len = read ( fd , src buffer, sizeof ( src buffer) - 1 ) ;
if ( len < 0 )
{
ereport ( LOG ,
@ -1042,36 +1058,50 @@ AddToDataDirLockFile(int target_line, const char *str)
close ( fd ) ;
return ;
}
buffer [ len ] = ' \0 ' ;
src buffer[ len ] = ' \0 ' ;
/*
* Skip over lines we are not supposed to rewrite .
* Advance over lines we are not supposed to rewrite , then copy them
* to destbuffer .
*/
ptr = buffer ;
src ptr= src buffer;
for ( lineno = 1 ; lineno < target_line ; lineno + + )
{
if ( ( ptr = strchr ( ptr , ' \n ' ) ) = = NULL )
if ( ( src ptr= strchr ( src ptr, ' \n ' ) ) = = NULL )
{
elog ( LOG , " bogus data in \" %s \" " , DIRECTORY_LOCK_FILE ) ;
close ( fd ) ;
return ;
}
ptr + + ;
src ptr+ + ;
}
memcpy ( destbuffer , srcbuffer , srcptr - srcbuffer ) ;
destptr = destbuffer + ( srcptr - srcbuffer ) ;
/*
* Write or rewrite the target line .
*/
snprintf ( ptr , buffer + sizeof ( buffer ) - ptr , " %s \n " , str ) ;
snprintf ( destptr , destbuffer + sizeof ( destbuffer ) - destptr , " %s \n " , str ) ;
destptr + = strlen ( destptr ) ;
/*
* If there are more lines in the old file , append them to destbuffer .
*/
if ( ( srcptr = strchr ( srcptr , ' \n ' ) ) ! = NULL )
{
srcptr + + ;
snprintf ( destptr , destbuffer + sizeof ( destbuffer ) - destptr , " %s " ,
srcptr ) ;
}
/*
* And rewrite the data . Since we write in a single kernel call , this
* update should appear atomic to onlookers .
*/
len = strlen ( buffer ) ;
len = strlen ( dest buffer) ;
errno = 0 ;
if ( lseek ( fd , ( off_t ) 0 , SEEK_SET ) ! = 0 | |
( int ) write ( fd , buffer , len ) ! = len )
( int ) write ( fd , dest buffer, len ) ! = len )
{
/* if write didn't set errno, assume problem is no disk space */
if ( errno = = 0 )
Tom Lane
13 years ago