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Fix a segfault in sqlite3OsLock() (CVS 1525)

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FossilOrigin-Name: 51348b82c4d5801091537b80059d770410774905
This commit is contained in:
danielk1977
2004-06-02 06:30:16 +00:00
parent 7a224deb5f
commit ecb2a9644b
4 changed files with 23 additions and 24 deletions
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21
src/os_unix.c
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@@ -61,7 +61,6 @@
*/
#include "os_common.h"
/*
** Here is the dirt on POSIX advisory locks: ANSI STD 1003.1 (1996)
** section 6.5.2.2 lines 483 through 490 specify that when a process
@@ -649,7 +648,6 @@ int sqlite3OsFileSize(OsFile *id, off_t *pSize){
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqlite3OsReadLock(OsFile *id){
int rc;
return sqlite3OsLock(id, SHARED_LOCK);
}
@@ -660,7 +658,6 @@ int sqlite3OsReadLock(OsFile *id){
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqlite3OsWriteLock(OsFile *id){
int rc;
return sqlite3OsLock(id, EXCLUSIVE_LOCK);
}
@@ -715,13 +712,14 @@ int sqlite3OsLock(OsFile *id, int locktype){
(pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
assert( locktype==SHARED_LOCK );
assert( id->locked==0 );
assert( pLock->cnt>0 );
id->locked = SHARED_LOCK;
pLock->cnt++;
id->pOpen->nLock++;
goto end_lock;
}
lock.l_len = 1L;
lock.l_len = 0L;
lock.l_whence = SEEK_SET;
/* If control gets to this point, then actually go ahead and make
@@ -729,7 +727,6 @@ int sqlite3OsLock(OsFile *id, int locktype){
*/
if( locktype==SHARED_LOCK ){
assert( pLock->cnt==0 );
assert( id->pOpen->nLock==0 );
assert( pLock->locktype==0 );
/* Grab a read-lock on byte 2. This ensures that no other process
@@ -753,7 +750,7 @@ int sqlite3OsLock(OsFile *id, int locktype){
rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
}else{
id->locked = SHARED_LOCK;
id->pOpen->nLock = 1;
id->pOpen->nLock++;
pLock->cnt = 1;
}
}else{
@@ -782,9 +779,11 @@ int sqlite3OsLock(OsFile *id, int locktype){
}
}
id->locked = locktype;
pLock->locktype = locktype;
assert(pLock->locktype==RESERVED_LOCK||(id->pOpen->nLock==1&&pLock->cnt==1));
if( rc==SQLITE_OK ){
id->locked = locktype;
pLock->locktype = locktype;
assert( pLock->locktype==RESERVED_LOCK || pLock->cnt==1 );
}
end_lock:
sqlite3OsLeaveMutex();
@@ -800,10 +799,10 @@ end_lock:
int sqlite3OsUnlock(OsFile *id){
int rc;
if( !id->locked ) return SQLITE_OK;
id->locked = 0;
sqlite3OsEnterMutex();
assert( id->pLock->cnt!=0 );
if( id->pLock->cnt>1 ){
id->locked = 0;
id->pLock->cnt--;
rc = SQLITE_OK;
}else{
@@ -819,9 +818,9 @@ int sqlite3OsUnlock(OsFile *id){
rc = SQLITE_OK;
id->pLock->cnt = 0;
id->pLock->locktype = 0;
id->locked = 0;
}
}
if( rc==SQLITE_OK ){
/* Decrement the count of locks against this same file. When the
** count reaches zero, close any other file descriptors whose close