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gerrit.openfyde.cn / chromium.googlesource.com / chromium / deps / sqlite / b232c23297248eb0753cf036c99f4bece9df992a / . / src / os_unix.c
blob: 26a653461fe9d7d589071ae44541c92175570eb7 [file] [log] [blame]
/*
** 2004 May 22
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to Unix systems.
**
** $Id: os_unix.c,v 1.211 2008/11/17 19:18:55 danielk1977 Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX /* This file is used on unix only */
/*
** If SQLITE_ENABLE_LOCKING_STYLE is defined and is non-zero, then several
** alternative locking implementations are provided:
**
** * POSIX locking (the default),
** * No locking,
** * Dot-file locking,
** * flock() locking,
** * AFP locking (OSX only),
** * Named POSIX semaphores (VXWorks only).
**
** SQLITE_ENABLE_LOCKING_STYLE only works on a Mac. It is turned on by
** default on a Mac and disabled on all other posix platforms.
*/
#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
# if defined(__DARWIN__)
# define SQLITE_ENABLE_LOCKING_STYLE 1
# else
# define SQLITE_ENABLE_LOCKING_STYLE 0
# endif
#endif
/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it. If the OS lacks
** large file support, these should be no-ops.
**
** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
** on the compiler command line. This is necessary if you are compiling
** on a recent machine (ex: RedHat 7.2) but you want your code to work
** on an older machine (ex: RedHat 6.0). If you compile on RedHat 7.2
** without this option, LFS is enable. But LFS does not exist in the kernel
** in RedHat 6.0, so the code won't work. Hence, for maximum binary
** portability you should omit LFS.
*/
#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE 1
# ifndef _FILE_OFFSET_BITS
# define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif
/*
** standard include files.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>
#include <errno.h>
#if SQLITE_ENABLE_LOCKING_STYLE
#include <sys/ioctl.h>
#if defined(__RTP__) || defined(_WRS_KERNEL)
#define lstat stat
#include <semaphore.h>
#include <limits.h>
#else
#include <sys/param.h>
#include <sys/mount.h>
#endif
#endif /* SQLITE_ENABLE_LOCKING_STYLE */
/*
** If we are to be thread-safe, include the pthreads header and define
** the SQLITE_UNIX_THREADS macro.
*/
#if SQLITE_THREADSAFE
# include <pthread.h>
# define SQLITE_UNIX_THREADS 1
#endif
/*
** Default permissions when creating a new file
*/
#ifndef SQLITE_DEFAULT_FILE_PERMISSIONS
# define SQLITE_DEFAULT_FILE_PERMISSIONS 0644
#endif
/*
** Maximum supported path-length.
*/
#define MAX_PATHNAME 512
/*
** The unixFile structure is subclass of sqlite3_file specific for the unix
** protability layer.
*/
typedef struct unixFile unixFile;
struct unixFile {
sqlite3_io_methods const *pMethod; /* Always the first entry */
#ifdef SQLITE_TEST
/* In test mode, increase the size of this structure a bit so that
** it is larger than the struct CrashFile defined in test6.c.
*/
char aPadding[32];
#endif
struct openCnt *pOpen; /* Info about all open fd's on this inode */
struct lockInfo *pLock; /* Info about locks on this inode */
#if SQLITE_ENABLE_LOCKING_STYLE
void *lockingContext; /* Locking style specific state */
#endif
int h; /* The file descriptor */
unsigned char locktype; /* The type of lock held on this fd */
int dirfd; /* File descriptor for the directory */
#if SQLITE_THREADSAFE
pthread_t tid; /* The thread that "owns" this unixFile */
#endif
int lastErrno; /* The unix errno from the last I/O error */
#if defined(__RTP__) || defined(_WRS_KERNEL)
int isDelete; /* Delete on close if true */
char *zRealpath;
#endif
};
/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"
/*
** Define various macros that are missing from some systems.
*/
#ifndef O_LARGEFILE
# define O_LARGEFILE 0
#endif
#ifdef SQLITE_DISABLE_LFS
# undef O_LARGEFILE
# define O_LARGEFILE 0
#endif
#ifndef O_NOFOLLOW
# define O_NOFOLLOW 0
#endif
#ifndef O_BINARY
# define O_BINARY 0
#endif
/*
** The DJGPP compiler environment looks mostly like Unix, but it
** lacks the fcntl() system call. So redefine fcntl() to be something
** that always succeeds. This means that locking does not occur under
** DJGPP. But it is DOS - what did you expect?
*/
#ifdef __DJGPP__
# define fcntl(A,B,C) 0
#endif
/*
** The threadid macro resolves to the thread-id or to 0. Used for
** testing and debugging only.
*/
#if SQLITE_THREADSAFE
#define threadid pthread_self()
#else
#define threadid 0
#endif
/*
** Set or check the unixFile.tid field. This field is set when an unixFile
** is first opened. All subsequent uses of the unixFile verify that the
** same thread is operating on the unixFile. Some operating systems do
** not allow locks to be overridden by other threads and that restriction
** means that sqlite3* database handles cannot be moved from one thread
** to another. This logic makes sure a user does not try to do that
** by mistake.
**
** Version 3.3.1 (2006-01-15): unixFile can be moved from one thread to
** another as long as we are running on a system that supports threads
** overriding each others locks (which now the most common behavior)
** or if no locks are held. But the unixFile.pLock field needs to be
** recomputed because its key includes the thread-id. See the
** transferOwnership() function below for additional information
*/
#if SQLITE_THREADSAFE
# define SET_THREADID(X) (X)->tid = pthread_self()
# define CHECK_THREADID(X) (threadsOverrideEachOthersLocks==0 && \
!pthread_equal((X)->tid, pthread_self()))
#else
# define SET_THREADID(X)
# define CHECK_THREADID(X) 0
#endif
/*
** 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
** sets or clears a lock, that operation overrides any prior locks set
** by the same process. It does not explicitly say so, but this implies
** that it overrides locks set by the same process using a different
** file descriptor. Consider this test case:
** int fd2 = open("./file2", O_RDWR|O_CREAT, 0644);
**
** Suppose ./file1 and ./file2 are really the same file (because
** one is a hard or symbolic link to the other) then if you set
** an exclusive lock on fd1, then try to get an exclusive lock
** on fd2, it works. I would have expected the second lock to
** fail since there was already a lock on the file due to fd1.
** But not so. Since both locks came from the same process, the
** second overrides the first, even though they were on different
** file descriptors opened on different file names.
**
** Bummer. If you ask me, this is broken. Badly broken. It means
** that we cannot use POSIX locks to synchronize file access among
** competing threads of the same process. POSIX locks will work fine
** to synchronize access for threads in separate processes, but not
** threads within the same process.
**
** To work around the problem, SQLite has to manage file locks internally
** on its own. Whenever a new database is opened, we have to find the
** specific inode of the database file (the inode is determined by the
** st_dev and st_ino fields of the stat structure that fstat() fills in)
** and check for locks already existing on that inode. When locks are
** created or removed, we have to look at our own internal record of the
** locks to see if another thread has previously set a lock on that same
** inode.
**
** The sqlite3_file structure for POSIX is no longer just an integer file
** descriptor. It is now a structure that holds the integer file
** descriptor and a pointer to a structure that describes the internal
** locks on the corresponding inode. There is one locking structure
** per inode, so if the same inode is opened twice, both unixFile structures
** point to the same locking structure. The locking structure keeps
** a reference count (so we will know when to delete it) and a "cnt"
** field that tells us its internal lock status. cnt==0 means the
** file is unlocked. cnt==-1 means the file has an exclusive lock.
** cnt>0 means there are cnt shared locks on the file.
**
** Any attempt to lock or unlock a file first checks the locking
** structure. The fcntl() system call is only invoked to set a
** POSIX lock if the internal lock structure transitions between
** a locked and an unlocked state.
**
** 2004-Jan-11:
** More recent discoveries about POSIX advisory locks. (The more
** I discover, the more I realize the a POSIX advisory locks are
** an abomination.)
**
** If you close a file descriptor that points to a file that has locks,
** all locks on that file that are owned by the current process are
** released. To work around this problem, each unixFile structure contains
** a pointer to an openCnt structure. There is one openCnt structure
** per open inode, which means that multiple unixFile can point to a single
** openCnt. When an attempt is made to close an unixFile, if there are
** other unixFile open on the same inode that are holding locks, the call
** to close() the file descriptor is deferred until all of the locks clear.
** The openCnt structure keeps a list of file descriptors that need to
** be closed and that list is walked (and cleared) when the last lock
** clears.
**
** First, under Linux threads, because each thread has a separate
** process ID, lock operations in one thread do not override locks
** to the same file in other threads. Linux threads behave like
** separate processes in this respect. But, if you close a file
** descriptor in linux threads, all locks are cleared, even locks
** on other threads and even though the other threads have different
** process IDs. Linux threads is inconsistent in this respect.
** (I'm beginning to think that linux threads is an abomination too.)
** The consequence of this all is that the hash table for the lockInfo
** structure has to include the process id as part of its key because
** locks in different threads are treated as distinct. But the
** openCnt structure should not include the process id in its
** key because close() clears lock on all threads, not just the current
** thread. Were it not for this goofiness in linux threads, we could
** combine the lockInfo and openCnt structures into a single structure.
**
** 2004-Jun-28:
** On some versions of linux, threads can override each others locks.
** On others not. Sometimes you can change the behavior on the same
** system by setting the LD_ASSUME_KERNEL environment variable. The
** POSIX standard is silent as to which behavior is correct, as far
** as I can tell, so other versions of unix might show the same
** inconsistency. There is no little doubt in my mind that posix
** advisory locks and linux threads are profoundly broken.
**
** To work around the inconsistencies, we have to test at runtime
** whether or not threads can override each others locks. This test
** is run once, the first time any lock is attempted. A static
** variable is set to record the results of this test for future
** use.
*/
/*
** An instance of the following structure serves as the key used
** to locate a particular lockInfo structure given its inode.
**
** If threads cannot override each others locks, then we set the
** lockKey.tid field to the thread ID. If threads can override
** each others locks then tid is always set to zero. tid is omitted
** if we compile without threading support.
*/
struct lockKey {
dev_t dev; /* Device number */
#if defined(__RTP__) || defined(_WRS_KERNEL)
void *rnam; /* Realname since inode unusable */
#else
ino_t ino; /* Inode number */
#endif
#if SQLITE_THREADSAFE
pthread_t tid; /* Thread ID or zero if threads can override each other */
#endif
};
/*
** An instance of the following structure is allocated for each open
** inode on each thread with a different process ID. (Threads have
** different process IDs on linux, but not on most other unixes.)
**
** A single inode can have multiple file descriptors, so each unixFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of unixFile pointing to it.
*/
struct lockInfo {
struct lockKey key; /* The lookup key */
int cnt; /* Number of SHARED locks held */
int locktype; /* One of SHARED_LOCK, RESERVED_LOCK etc. */
int nRef; /* Number of pointers to this structure */
struct lockInfo *pNext, *pPrev; /* List of all lockInfo objects */
};
/*
** An instance of the following structure serves as the key used
** to locate a particular openCnt structure given its inode. This
** is the same as the lockKey except that the thread ID is omitted.
*/
struct openKey {
dev_t dev; /* Device number */
#if defined(__RTP__) || defined(_WRS_KERNEL)
void *rnam; /* Realname since inode unusable */
#else
ino_t ino; /* Inode number */
#endif
};
/*
** An instance of the following structure is allocated for each open
** inode. This structure keeps track of the number of locks on that
** inode. If a close is attempted against an inode that is holding
** locks, the close is deferred until all locks clear by adding the
** file descriptor to be closed to the pending list.
*/
struct openCnt {
struct openKey key; /* The lookup key */
int nRef; /* Number of pointers to this structure */
int nLock; /* Number of outstanding locks */
int nPending; /* Number of pending close() operations */
int *aPending; /* Malloced space holding fd's awaiting a close() */
#if defined(__RTP__) || defined(_WRS_KERNEL)
sem_t *pSem; /* Named POSIX semaphore */
char aSemName[MAX_PATHNAME+1]; /* Name of that semaphore */
#endif
struct openCnt *pNext, *pPrev; /* List of all openCnt objects */
};
/*
** List of all lockInfo and openCnt objects. This used to be a hash
** table. But the number of objects is rarely more than a dozen and
** never exceeds a few thousand. And lookup is not on a critical
** path oo a simple linked list will suffice.
*/
static struct lockInfo *lockList = 0;
static struct openCnt *openList = 0;
#if defined(__RTP__) || defined(_WRS_KERNEL)
/*
** This hash table is used to bind the canonical file name to a
** unixFile structure and use the hash key (= canonical name)
** instead of the Inode number of the file to find the matching
** lockInfo and openCnt structures. It also helps to make the
** name of the semaphore when LOCKING_STYLE_NAMEDSEM is used
** for the file.
*/
static Hash nameHash;
#endif
/*
** The locking styles are associated with the different file locking
** capabilities supported by different file systems.
**
** POSIX locking style fully supports shared and exclusive byte-range locks
** AFP locking only supports exclusive byte-range locks
** FLOCK only supports a single file-global exclusive lock
** DOTLOCK isn't a true locking style, it refers to the use of a special
** file named the same as the database file with a '.lock' extension, this
** can be used on file systems that do not offer any reliable file locking
** NO locking means that no locking will be attempted, this is only used for
** read-only file systems currently
** NAMEDSEM is similar to DOTLOCK but uses a named semaphore instead of an
** indicator file.
** UNSUPPORTED means that no locking will be attempted, this is only used for
** file systems that are known to be unsupported
*/
#define LOCKING_STYLE_POSIX 1
#define LOCKING_STYLE_NONE 2
#define LOCKING_STYLE_DOTFILE 3
#define LOCKING_STYLE_FLOCK 4
#define LOCKING_STYLE_AFP 5
#define LOCKING_STYLE_NAMEDSEM 6
/*
** Only set the lastErrno if the error code is a real error and not
** a normal expected return code of SQLITE_BUSY or SQLITE_OK
*/
#define IS_LOCK_ERROR(x) ((x != SQLITE_OK) && (x != SQLITE_BUSY))
/*
** Helper functions to obtain and relinquish the global mutex.
*/
static void enterMutex(void){
sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
static void leaveMutex(void){
sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
}
#if SQLITE_THREADSAFE
/*
** This variable records whether or not threads can override each others
** locks.
**
** 0: No. Threads cannot override each others locks.
** 1: Yes. Threads can override each others locks.
** -1: We don't know yet.
**
** On some systems, we know at compile-time if threads can override each
** others locks. On those systems, the SQLITE_THREAD_OVERRIDE_LOCK macro
** will be set appropriately. On other systems, we have to check at
** runtime. On these latter systems, SQLTIE_THREAD_OVERRIDE_LOCK is
** undefined.
**
** This variable normally has file scope only. But during testing, we make
** it a global so that the test code can change its value in order to verify
** that the right stuff happens in either case.
*/
#ifndef SQLITE_THREAD_OVERRIDE_LOCK
# define SQLITE_THREAD_OVERRIDE_LOCK -1
#endif
#ifdef SQLITE_TEST
int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
#else
static int threadsOverrideEachOthersLocks = SQLITE_THREAD_OVERRIDE_LOCK;
#endif
/*
** This structure holds information passed into individual test
** threads by the testThreadLockingBehavior() routine.
*/
struct threadTestData {
int fd; /* File to be locked */
struct flock lock; /* The locking operation */
int result; /* Result of the locking operation */
};
#ifdef SQLITE_LOCK_TRACE
/*
** Print out information about all locking operations.
**
** This routine is used for troubleshooting locks on multithreaded
** platforms. Enable by compiling with the -DSQLITE_LOCK_TRACE
** command-line option on the compiler. This code is normally
** turned off.
*/
static int lockTrace(int fd, int op, struct flock *p){
char *zOpName, *zType;
int s;
int savedErrno;
if( op==F_GETLK ){
zOpName = "GETLK";
}else if( op==F_SETLK ){
zOpName = "SETLK";
}else{
s = fcntl(fd, op, p);
sqlite3DebugPrintf("fcntl unknown %d %d %d\n", fd, op, s);
return s;
}
if( p->l_type==F_RDLCK ){
zType = "RDLCK";
}else if( p->l_type==F_WRLCK ){
zType = "WRLCK";
}else if( p->l_type==F_UNLCK ){
zType = "UNLCK";
}else{
assert( 0 );
}
assert( p->l_whence==SEEK_SET );
s = fcntl(fd, op, p);
savedErrno = errno;
sqlite3DebugPrintf("fcntl %d %d %s %s %d %d %d %d\n",
threadid, fd, zOpName, zType, (int)p->l_start, (int)p->l_len,
(int)p->l_pid, s);
if( s==(-1) && op==F_SETLK && (p->l_type==F_RDLCK || p->l_type==F_WRLCK) ){
struct flock l2;
l2 = *p;
fcntl(fd, F_GETLK, &l2);
if( l2.l_type==F_RDLCK ){
zType = "RDLCK";
}else if( l2.l_type==F_WRLCK ){
zType = "WRLCK";
}else if( l2.l_type==F_UNLCK ){
zType = "UNLCK";
}else{
assert( 0 );
}
sqlite3DebugPrintf("fcntl-failure-reason: %s %d %d %d\n",
zType, (int)l2.l_start, (int)l2.l_len, (int)l2.l_pid);
}
errno = savedErrno;
return s;
}
#define fcntl lockTrace
#endif /* SQLITE_LOCK_TRACE */
#ifdef __linux__
/*
** This function is used as the main routine for a thread launched by
** testThreadLockingBehavior(). It tests whether the shared-lock obtained
** by the main thread in testThreadLockingBehavior() conflicts with a
** hypothetical write-lock obtained by this thread on the same file.
**
** The write-lock is not actually acquired, as this is not possible if
** the file is open in read-only mode (see ticket #3472).
*/
static void *threadLockingTest(void *pArg){
struct threadTestData *pData = (struct threadTestData*)pArg;
pData->result = fcntl(pData->fd, F_GETLK, &pData->lock);
return pArg;
}
/*
** This procedure attempts to determine whether or not threads
** can override each others locks then sets the
** threadsOverrideEachOthersLocks variable appropriately.
*/
static void testThreadLockingBehavior(int fd_orig){
int fd;
int rc;
struct threadTestData d;
struct flock l;
pthread_t t;
fd = dup(fd_orig);
if( fd<0 ) return;
memset(&l, 0, sizeof(l));
l.l_type = F_RDLCK;
l.l_len = 1;
l.l_start = 0;
l.l_whence = SEEK_SET;
rc = fcntl(fd_orig, F_SETLK, &l);
if( rc!=0 ) return;
memset(&d, 0, sizeof(d));
d.fd = fd;
d.lock = l;
d.lock.l_type = F_WRLCK;
pthread_create(&t, 0, threadLockingTest, &d);
pthread_join(t, 0);
close(fd);
if( d.result!=0 ) return;
threadsOverrideEachOthersLocks = (d.lock.l_type==F_UNLCK);
}
#else
/*
** On anything other than linux, assume threads override each others locks.
*/
static void testThreadLockingBehavior(int fd_orig){
threadsOverrideEachOthersLocks = 1;
}
#endif /* __linux__ */
#endif /* SQLITE_THREADSAFE */
/*
** Release a lockInfo structure previously allocated by findLockInfo().
*/
static void releaseLockInfo(struct lockInfo *pLock){
if( pLock ){
pLock->nRef--;
if( pLock->nRef==0 ){
if( pLock->pPrev ){
assert( pLock->pPrev->pNext==pLock );
pLock->pPrev->pNext = pLock->pNext;
}else{
assert( lockList==pLock );
lockList = pLock->pNext;
}
if( pLock->pNext ){
assert( pLock->pNext->pPrev==pLock );
pLock->pNext->pPrev = pLock->pPrev;
}
sqlite3_free(pLock);
}
}
}
/*
** Release a openCnt structure previously allocated by findLockInfo().
*/
static void releaseOpenCnt(struct openCnt *pOpen){
if( pOpen ){
pOpen->nRef--;
if( pOpen->nRef==0 ){
if( pOpen->pPrev ){
assert( pOpen->pPrev->pNext==pOpen );
pOpen->pPrev->pNext = pOpen->pNext;
}else{
assert( openList==pOpen );
openList = pOpen->pNext;
}
if( pOpen->pNext ){
assert( pOpen->pNext->pPrev==pOpen );
pOpen->pNext->pPrev = pOpen->pPrev;
}
sqlite3_free(pOpen->aPending);
sqlite3_free(pOpen);
}
}
}
#if defined(__RTP__) || defined(_WRS_KERNEL)
/*
** Implementation of a realpath() like function for vxWorks
** to determine canonical path name from given name. It does
** not support symlinks. Neither does it handle volume prefixes.
*/
char *
vxrealpath(const char *pathname, int dostat)
{
struct stat sbuf;
int len;
char *where, *ptr, *last;
char *result, *curpath, *workpath, *namebuf;
len = pathconf(pathname, _PC_PATH_MAX);
if( len<0 ){
len = PATH_MAX;
}
result = sqlite3_malloc(len * 4);
if( !result ){
return 0;
}
curpath = result + len;
workpath = curpath + len;
namebuf = workpath + len;
strcpy(curpath, pathname);
if( *pathname!='/' ){
if( !getcwd(workpath, len) ){
sqlite3_free(result);
return 0;
}
}else{
*workpath = '\0';
}
where = curpath;
while( *where ){
if( !strcmp(where, ".") ){
where++;
continue;
}
if( !strncmp(where, "./", 2) ){
where += 2;
continue;
}
if( !strncmp(where, "../", 3) ){
where += 3;
ptr = last = workpath;
while( *ptr ){
if( *ptr=='/' ){
last = ptr;
}
ptr++;
}
*last = '\0';
continue;
}
ptr = strchr(where, '/');
if( !ptr ){
ptr = where + strlen(where) - 1;
}else{
*ptr = '\0';
}
strcpy(namebuf, workpath);
for( last = namebuf; *last; last++ ){
continue;
}
if( *--last!='/' ){
strcat(namebuf, "/");
}
strcat(namebuf, where);
where = ++ptr;
if( dostat ){
if( stat(namebuf, &sbuf)==-1 ){
sqlite3_free(result);
return 0;
}
if( (sbuf.st_mode & S_IFDIR)==S_IFDIR ){
strcpy(workpath, namebuf);
continue;
}
if( *where ){
sqlite3_free(result);
return 0;
}
}
strcpy(workpath, namebuf);
}
strcpy(result, workpath);
return result;
}
#endif
#if SQLITE_ENABLE_LOCKING_STYLE
/*
** Tests a byte-range locking query to see if byte range locks are
** supported, if not we fall back to dotlockLockingStyle.
** On vxWorks we fall back to namedsemLockingStyle.
*/
static int testLockingStyle(int fd){
struct flock lockInfo;
/* Test byte-range lock using fcntl(). If the call succeeds,
** assume that the file-system supports POSIX style locks.
*/
lockInfo.l_len = 1;
lockInfo.l_start = 0;
lockInfo.l_whence = SEEK_SET;
lockInfo.l_type = F_RDLCK;
if( fcntl(fd, F_GETLK, &lockInfo)!=-1 ) {
return LOCKING_STYLE_POSIX;
}
/* Testing for flock() can give false positives. So if if the above
** test fails, then we fall back to using dot-file style locking.
*/
#if defined(__RTP__) || defined(_WRS_KERNEL)
return LOCKING_STYLE_NAMEDSEM;
#else
return LOCKING_STYLE_DOTFILE;
#endif
}
#endif
/*
** If SQLITE_ENABLE_LOCKING_STYLE is defined, this function Examines the
** f_fstypename entry in the statfs structure as returned by stat() for
** the file system hosting the database file and selects the appropriate
** locking style based on its value. These values and assignments are
** based on Darwin/OSX behavior and have not been thoroughly tested on
** other systems.
**
** If SQLITE_ENABLE_LOCKING_STYLE is not defined, this function always
** returns LOCKING_STYLE_POSIX.
*/
static int detectLockingStyle(
sqlite3_vfs *pVfs,
const char *filePath,
int fd
){
#if SQLITE_ENABLE_LOCKING_STYLE
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( !filePath ){
return LOCKING_STYLE_NONE;
}
if( pVfs->pAppData ){
return SQLITE_PTR_TO_INT(pVfs->pAppData);
}
if (access(filePath, 0) != -1){
return testLockingStyle(fd);
}
#else
struct Mapping {
const char *zFilesystem;
int eLockingStyle;
} aMap[] = {
{ "hfs", LOCKING_STYLE_POSIX },
{ "ufs", LOCKING_STYLE_POSIX },
{ "afpfs", LOCKING_STYLE_AFP },
#ifdef SQLITE_ENABLE_AFP_LOCKING_SMB
{ "smbfs", LOCKING_STYLE_AFP },
#else
{ "smbfs", LOCKING_STYLE_FLOCK },
#endif
{ "msdos", LOCKING_STYLE_DOTFILE },
{ "webdav", LOCKING_STYLE_NONE },
{ 0, 0 }
};
int i;
struct statfs fsInfo;
if( !filePath ){
return LOCKING_STYLE_NONE;
}
if( pVfs->pAppData ){
return SQLITE_PTR_TO_INT(pVfs->pAppData);
}
if( statfs(filePath, &fsInfo) != -1 ){
if( fsInfo.f_flags & MNT_RDONLY ){
return LOCKING_STYLE_NONE;
}
for(i=0; aMap[i].zFilesystem; i++){
if( strcmp(fsInfo.f_fstypename, aMap[i].zFilesystem)==0 ){
return aMap[i].eLockingStyle;
}
}
}
/* Default case. Handles, amongst others, "nfs". */
return testLockingStyle(fd);
#endif
#endif
return LOCKING_STYLE_POSIX;
}
/*
** Given a file descriptor, locate lockInfo and openCnt structures that
** describes that file descriptor. Create new ones if necessary. The
** return values might be uninitialized if an error occurs.
**
** Return an appropriate error code.
*/
static int findLockInfo(
int fd, /* The file descriptor used in the key */
#if defined(__RTP__) || defined(_WRS_KERNEL)
void *rnam, /* vxWorks realname */
#endif
struct lockInfo **ppLock, /* Return the lockInfo structure here */
struct openCnt **ppOpen /* Return the openCnt structure here */
){
int rc;
struct lockKey key1;
struct openKey key2;
struct stat statbuf;
struct lockInfo *pLock;
struct openCnt *pOpen;
rc = fstat(fd, &statbuf);
if( rc!=0 ){
#ifdef EOVERFLOW
if( errno==EOVERFLOW ) return SQLITE_NOLFS;
#endif
return SQLITE_IOERR;
}
/* On OS X on an msdos filesystem, the inode number is reported
** incorrectly for zero-size files. See ticket #3260. To work
** around this problem (we consider it a bug in OS X, not SQLite)
** we always increase the file size to 1 by writing a single byte
** prior to accessing the inode number. The one byte written is
** an ASCII 'S' character which also happens to be the first byte
** in the header of every SQLite database. In this way, if there
** is a race condition such that another thread has already populated
** the first page of the database, no damage is done.
*/
if( statbuf.st_size==0 ){
write(fd, "S", 1);
rc = fstat(fd, &statbuf);
if( rc!=0 ){
return SQLITE_IOERR;
}
}
memset(&key1, 0, sizeof(key1));
key1.dev = statbuf.st_dev;
#if defined(__RTP__) || defined(_WRS_KERNEL)
key1.rnam = rnam;
#else
key1.ino = statbuf.st_ino;
#endif
#if SQLITE_THREADSAFE
if( threadsOverrideEachOthersLocks<0 ){
testThreadLockingBehavior(fd);
}
key1.tid = threadsOverrideEachOthersLocks ? 0 : pthread_self();
#endif
memset(&key2, 0, sizeof(key2));
key2.dev = statbuf.st_dev;
#if defined(__RTP__) || defined(_WRS_KERNEL)
key2.rnam = rnam;
#else
key2.ino = statbuf.st_ino;
#endif
pLock = lockList;
while( pLock && memcmp(&key1, &pLock->key, sizeof(key1)) ){
pLock = pLock->pNext;
}
if( pLock==0 ){
pLock = sqlite3_malloc( sizeof(*pLock) );
if( pLock==0 ){
rc = SQLITE_NOMEM;
goto exit_findlockinfo;
}
pLock->key = key1;
pLock->nRef = 1;
pLock->cnt = 0;
pLock->locktype = 0;
pLock->pNext = lockList;
pLock->pPrev = 0;
if( lockList ) lockList->pPrev = pLock;
lockList = pLock;
}else{
pLock->nRef++;
}
*ppLock = pLock;
if( ppOpen!=0 ){
pOpen = openList;
while( pOpen && memcmp(&key2, &pOpen->key, sizeof(key2)) ){
pOpen = pOpen->pNext;
}
if( pOpen==0 ){
pOpen = sqlite3_malloc( sizeof(*pOpen) );
if( pOpen==0 ){
releaseLockInfo(pLock);
rc = SQLITE_NOMEM;
goto exit_findlockinfo;
}
pOpen->key = key2;
pOpen->nRef = 1;
pOpen->nLock = 0;
pOpen->nPending = 0;
pOpen->aPending = 0;
pOpen->pNext = openList;
pOpen->pPrev = 0;
if( openList ) openList->pPrev = pOpen;
openList = pOpen;
#if defined(__RTP__) || defined(_WRS_KERNEL)
pOpen->pSem = NULL;
pOpen->aSemName[0] = '\0';
#endif
}else{
pOpen->nRef++;
}
*ppOpen = pOpen;
}
exit_findlockinfo:
return rc;
}
#ifdef SQLITE_DEBUG
/*
** Helper function for printing out trace information from debugging
** binaries. This returns the string represetation of the supplied
** integer lock-type.
*/
static const char *locktypeName(int locktype){
switch( locktype ){
case NO_LOCK: return "NONE";
case SHARED_LOCK: return "SHARED";
case RESERVED_LOCK: return "RESERVED";
case PENDING_LOCK: return "PENDING";
case EXCLUSIVE_LOCK: return "EXCLUSIVE";
}
return "ERROR";
}
#endif
/*
** If we are currently in a different thread than the thread that the
** unixFile argument belongs to, then transfer ownership of the unixFile
** over to the current thread.
**
** A unixFile is only owned by a thread on systems where one thread is
** unable to override locks created by a different thread. RedHat9 is
** an example of such a system.
**
** Ownership transfer is only allowed if the unixFile is currently unlocked.
** If the unixFile is locked and an ownership is wrong, then return
** SQLITE_MISUSE. SQLITE_OK is returned if everything works.
*/
#if SQLITE_THREADSAFE
static int transferOwnership(unixFile *pFile){
int rc;
pthread_t hSelf;
if( threadsOverrideEachOthersLocks ){
/* Ownership transfers not needed on this system */
return SQLITE_OK;
}
hSelf = pthread_self();
if( pthread_equal(pFile->tid, hSelf) ){
/* We are still in the same thread */
OSTRACE1("No-transfer, same thread\n");
return SQLITE_OK;
}
if( pFile->locktype!=NO_LOCK ){
/* We cannot change ownership while we are holding a lock! */
return SQLITE_MISUSE;
}
OSTRACE4("Transfer ownership of %d from %d to %d\n",
pFile->h, pFile->tid, hSelf);
pFile->tid = hSelf;
if (pFile->pLock != NULL) {
releaseLockInfo(pFile->pLock);
#if defined(__RTP__) || defined(_WRS_KERNEL)
rc = findLockInfo(pFile->h, pFile->zRealpath, &pFile->pLock, 0);
#else
rc = findLockInfo(pFile->h, &pFile->pLock, 0);
#endif
OSTRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h,
locktypeName(pFile->locktype),
locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
return rc;
} else {
return SQLITE_OK;
}
}
#else
/* On single-threaded builds, ownership transfer is a no-op */
# define transferOwnership(X) SQLITE_OK
#endif
/*
** Seek to the offset passed as the second argument, then read cnt
** bytes into pBuf. Return the number of bytes actually read.
**
** NB: If you define USE_PREAD or USE_PREAD64, then it might also
** be necessary to define _XOPEN_SOURCE to be 500. This varies from
** one system to another. Since SQLite does not define USE_PREAD
** any any form by default, we will not attempt to define _XOPEN_SOURCE.
** See tickets #2741 and #2681.
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
int got;
i64 newOffset;
TIMER_START;
#if defined(USE_PREAD)
got = pread(id->h, pBuf, cnt, offset);
SimulateIOError( got = -1 );
#elif defined(USE_PREAD64)
got = pread64(id->h, pBuf, cnt, offset);
SimulateIOError( got = -1 );
#else
newOffset = lseek(id->h, offset, SEEK_SET);
SimulateIOError( newOffset-- );
if( newOffset!=offset ){
return -1;
}
got = read(id->h, pBuf, cnt);
#endif
TIMER_END;
OSTRACE5("READ %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
return got;
}
/*
** Read data from a file into a buffer. Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
static int unixRead(
sqlite3_file *id,
void *pBuf,
int amt,
sqlite3_int64 offset
){
int got;
assert( id );
got = seekAndRead((unixFile*)id, offset, pBuf, amt);
if( got==amt ){
return SQLITE_OK;
}else if( got<0 ){
return SQLITE_IOERR_READ;
}else{
/* Unread parts of the buffer must be zero-filled */
memset(&((char*)pBuf)[got], 0, amt-got);
return SQLITE_IOERR_SHORT_READ;
}
}
/*
** Seek to the offset in id->offset then read cnt bytes into pBuf.
** Return the number of bytes actually read. Update the offset.
*/
static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
int got;
i64 newOffset;
TIMER_START;
#if defined(USE_PREAD)
got = pwrite(id->h, pBuf, cnt, offset);
#elif defined(USE_PREAD64)
got = pwrite64(id->h, pBuf, cnt, offset);
#else
newOffset = lseek(id->h, offset, SEEK_SET);
if( newOffset!=offset ){
return -1;
}
got = write(id->h, pBuf, cnt);
#endif
TIMER_END;
OSTRACE5("WRITE %-3d %5d %7lld %llu\n", id->h, got, offset, TIMER_ELAPSED);
return got;
}
/*
** Write data from a buffer into a file. Return SQLITE_OK on success
** or some other error code on failure.
*/
static int unixWrite(
sqlite3_file *id,
const void *pBuf,
int amt,
sqlite3_int64 offset
){
int wrote = 0;
assert( id );
assert( amt>0 );
while( amt>0 && (wrote = seekAndWrite((unixFile*)id, offset, pBuf, amt))>0 ){
amt -= wrote;
offset += wrote;
pBuf = &((char*)pBuf)[wrote];
}
SimulateIOError(( wrote=(-1), amt=1 ));
SimulateDiskfullError(( wrote=0, amt=1 ));
if( amt>0 ){
if( wrote<0 ){
return SQLITE_IOERR_WRITE;
}else{
return SQLITE_FULL;
}
}
return SQLITE_OK;
}
#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs. This is used to test
** that syncs and fullsyncs are occuring at the right times.
*/
int sqlite3_sync_count = 0;
int sqlite3_fullsync_count = 0;
#endif
/*
** Use the fdatasync() API only if the HAVE_FDATASYNC macro is defined.
** Otherwise use fsync() in its place.
*/
#ifndef HAVE_FDATASYNC
# define fdatasync fsync
#endif
/*
** Define HAVE_FULLFSYNC to 0 or 1 depending on whether or not
** the F_FULLFSYNC macro is defined. F_FULLFSYNC is currently
** only available on Mac OS X. But that could change.
*/
#ifdef F_FULLFSYNC
# define HAVE_FULLFSYNC 1
#else
# define HAVE_FULLFSYNC 0
#endif
/*
** The fsync() system call does not work as advertised on many
** unix systems. The following procedure is an attempt to make
** it work better.
**
** The SQLITE_NO_SYNC macro disables all fsync()s. This is useful
** for testing when we want to run through the test suite quickly.
** You are strongly advised *not* to deploy with SQLITE_NO_SYNC
** enabled, however, since with SQLITE_NO_SYNC enabled, an OS crash
** or power failure will likely corrupt the database file.
*/
static int full_fsync(int fd, int fullSync, int dataOnly){
int rc;
/* Record the number of times that we do a normal fsync() and
** FULLSYNC. This is used during testing to verify that this procedure
** gets called with the correct arguments.
*/
#ifdef SQLITE_TEST
if( fullSync ) sqlite3_fullsync_count++;
sqlite3_sync_count++;
#endif
/* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
** no-op
*/
#ifdef SQLITE_NO_SYNC
rc = SQLITE_OK;
#else
#if HAVE_FULLFSYNC
if( fullSync ){
rc = fcntl(fd, F_FULLFSYNC, 0);
}else{
rc = 1;
}
/* If the FULLFSYNC failed, fall back to attempting an fsync().
* It shouldn't be possible for fullfsync to fail on the local
* file system (on OSX), so failure indicates that FULLFSYNC
* isn't supported for this file system. So, attempt an fsync
* and (for now) ignore the overhead of a superfluous fcntl call.
* It'd be better to detect fullfsync support once and avoid
* the fcntl call every time sync is called.
*/
if( rc ) rc = fsync(fd);
#else
if( dataOnly ){
rc = fdatasync(fd);
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( rc==-1 && errno==ENOTSUP ){
rc = fsync(fd);
}
#endif
}else{
rc = fsync(fd);
}
#endif /* HAVE_FULLFSYNC */
#endif /* defined(SQLITE_NO_SYNC) */
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( rc!= -1 ){
rc = 0;
}
#endif
return rc;
}
/*
** Make sure all writes to a particular file are committed to disk.
**
** If dataOnly==0 then both the file itself and its metadata (file
** size, access time, etc) are synced. If dataOnly!=0 then only the
** file data is synced.
**
** Under Unix, also make sure that the directory entry for the file
** has been created by fsync-ing the directory that contains the file.
** If we do not do this and we encounter a power failure, the directory
** entry for the journal might not exist after we reboot. The next
** SQLite to access the file will not know that the journal exists (because
** the directory entry for the journal was never created) and the transaction
** will not roll back - possibly leading to database corruption.
*/
static int unixSync(sqlite3_file *id, int flags){
int rc;
unixFile *pFile = (unixFile*)id;
int isDataOnly = (flags&SQLITE_SYNC_DATAONLY);
int isFullsync = (flags&0x0F)==SQLITE_SYNC_FULL;
/* Check that one of SQLITE_SYNC_NORMAL or FULL was passed */
assert((flags&0x0F)==SQLITE_SYNC_NORMAL
|| (flags&0x0F)==SQLITE_SYNC_FULL
);
/* Unix cannot, but some systems may return SQLITE_FULL from here. This
** line is to test that doing so does not cause any problems.
*/
SimulateDiskfullError( return SQLITE_FULL );
assert( pFile );
OSTRACE2("SYNC %-3d\n", pFile->h);
rc = full_fsync(pFile->h, isFullsync, isDataOnly);
SimulateIOError( rc=1 );
if( rc ){
return SQLITE_IOERR_FSYNC;
}
if( pFile->dirfd>=0 ){
OSTRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd,
HAVE_FULLFSYNC, isFullsync);
#ifndef SQLITE_DISABLE_DIRSYNC
/* The directory sync is only attempted if full_fsync is
** turned off or unavailable. If a full_fsync occurred above,
** then the directory sync is superfluous.
*/
if( (!HAVE_FULLFSYNC || !isFullsync) && full_fsync(pFile->dirfd,0,0) ){
/*
** We have received multiple reports of fsync() returning
** errors when applied to directories on certain file systems.
** A failed directory sync is not a big deal. So it seems
** better to ignore the error. Ticket #1657
*/
/* return SQLITE_IOERR; */
}
#endif
close(pFile->dirfd); /* Only need to sync once, so close the directory */
pFile->dirfd = -1; /* when we are done. */
}
return SQLITE_OK;
}
/*
** Truncate an open file to a specified size
*/
static int unixTruncate(sqlite3_file *id, i64 nByte){
int rc;
assert( id );
SimulateIOError( return SQLITE_IOERR_TRUNCATE );
rc = ftruncate(((unixFile*)id)->h, (off_t)nByte);
if( rc ){
return SQLITE_IOERR_TRUNCATE;
}else{
return SQLITE_OK;
}
}
/*
** Determine the current size of a file in bytes
*/
static int unixFileSize(sqlite3_file *id, i64 *pSize){
int rc;
struct stat buf;
assert( id );
rc = fstat(((unixFile*)id)->h, &buf);
SimulateIOError( rc=1 );
if( rc!=0 ){
return SQLITE_IOERR_FSTAT;
}
*pSize = buf.st_size;
/* When opening a zero-size database, the findLockInfo() procedure
** writes a single byte into that file in order to work around a bug
** in the OS-X msdos filesystem. In order to avoid problems with upper
** layers, we need to report this file size as zero even though it is
** really 1. Ticket #3260.
*/
if( *pSize==1 ) *pSize = 0;
return SQLITE_OK;
}
/*
** This routine translates a standard POSIX errno code into something
** useful to the clients of the sqlite3 functions. Specifically, it is
** intended to translate a variety of "try again" errors into SQLITE_BUSY
** and a variety of "please close the file descriptor NOW" errors into
** SQLITE_IOERR
**
** Errors during initialization of locks, or file system support for locks,
** should handle ENOLCK, ENOTSUP, EOPNOTSUPP separately.
*/
static int sqliteErrorFromPosixError(int posixError, int sqliteIOErr) {
switch (posixError) {
case 0:
return SQLITE_OK;
case EAGAIN:
case ETIMEDOUT:
case EBUSY:
case EINTR:
case ENOLCK:
/* random NFS retry error, unless during file system support
* introspection, in which it actually means what it says */
return SQLITE_BUSY;
case EACCES:
/* EACCES is like EAGAIN during locking operations, but not any other time*/
if( (sqliteIOErr == SQLITE_IOERR_LOCK) ||
(sqliteIOErr == SQLITE_IOERR_UNLOCK) ||
(sqliteIOErr == SQLITE_IOERR_RDLOCK) ||
(sqliteIOErr == SQLITE_IOERR_CHECKRESERVEDLOCK) ){
return SQLITE_BUSY;
}
/* else fall through */
case EPERM:
return SQLITE_PERM;
case EDEADLK:
return SQLITE_IOERR_BLOCKED;
#if EOPNOTSUPP!=ENOTSUP
case EOPNOTSUPP:
/* something went terribly awry, unless during file system support
* introspection, in which it actually means what it says */
#endif
#ifdef ENOTSUP
case ENOTSUP:
/* invalid fd, unless during file system support introspection, in which
* it actually means what it says */
#endif
case EIO:
case EBADF:
case EINVAL:
case ENOTCONN:
case ENODEV:
case ENXIO:
case ENOENT:
case ESTALE:
case ENOSYS:
/* these should force the client to close the file and reconnect */
default:
return sqliteIOErr;
}
}
/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero. The return value
** is set to SQLITE_OK unless an I/O error occurs during lock checking.
*/
static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
int rc = SQLITE_OK;
int reserved = 0;
unixFile *pFile = (unixFile*)id;
SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
assert( pFile );
enterMutex(); /* Because pFile->pLock is shared across threads */
/* Check if a thread in this process holds such a lock */
if( pFile->pLock->locktype>SHARED_LOCK ){
reserved = 1;
}
/* Otherwise see if some other process holds it.
*/
if( !reserved ){
struct flock lock;
lock.l_whence = SEEK_SET;
lock.l_start = RESERVED_BYTE;
lock.l_len = 1;
lock.l_type = F_WRLCK;
if (-1 == fcntl(pFile->h, F_GETLK, &lock)) {
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
pFile->lastErrno = tErrno;
} else if( lock.l_type!=F_UNLCK ){
reserved = 1;
}
}
leaveMutex();
OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
*pResOut = reserved;
return rc;
}
/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
**
** (1) SHARED_LOCK
** (2) RESERVED_LOCK
** (3) PENDING_LOCK
** (4) EXCLUSIVE_LOCK
**
** Sometimes when requesting one lock state, additional lock states
** are inserted in between. The locking might fail on one of the later
** transitions leaving the lock state different from what it started but
** still short of its goal. The following chart shows the allowed
** transitions and the inserted intermediate states:
**
** UNLOCKED -> SHARED
** SHARED -> RESERVED
** SHARED -> (PENDING) -> EXCLUSIVE
** RESERVED -> (PENDING) -> EXCLUSIVE
** PENDING -> EXCLUSIVE
**
** This routine will only increase a lock. Use the sqlite3OsUnlock()
** routine to lower a locking level.
*/
static int unixLock(sqlite3_file *id, int locktype){
/* The following describes the implementation of the various locks and
** lock transitions in terms of the POSIX advisory shared and exclusive
** lock primitives (called read-locks and write-locks below, to avoid
** confusion with SQLite lock names). The algorithms are complicated
** slightly in order to be compatible with windows systems simultaneously
** accessing the same database file, in case that is ever required.
**
** Symbols defined in os.h indentify the 'pending byte' and the 'reserved
** byte', each single bytes at well known offsets, and the 'shared byte
** range', a range of 510 bytes at a well known offset.
**
** To obtain a SHARED lock, a read-lock is obtained on the 'pending
** byte'. If this is successful, a random byte from the 'shared byte
** range' is read-locked and the lock on the 'pending byte' released.
**
** A process may only obtain a RESERVED lock after it has a SHARED lock.
** A RESERVED lock is implemented by grabbing a write-lock on the
** 'reserved byte'.
**
** A process may only obtain a PENDING lock after it has obtained a
** SHARED lock. A PENDING lock is implemented by obtaining a write-lock
** on the 'pending byte'. This ensures that no new SHARED locks can be
** obtained, but existing SHARED locks are allowed to persist. A process
** does not have to obtain a RESERVED lock on the way to a PENDING lock.
** This property is used by the algorithm for rolling back a journal file
** after a crash.
**
** An EXCLUSIVE lock, obtained after a PENDING lock is held, is
** implemented by obtaining a write-lock on the entire 'shared byte
** range'. Since all other locks require a read-lock on one of the bytes
** within this range, this ensures that no other locks are held on the
** database.
**
** The reason a single byte cannot be used instead of the 'shared byte
** range' is that some versions of windows do not support read-locks. By
** locking a random byte from a range, concurrent SHARED locks may exist
** even if the locking primitive used is always a write-lock.
*/
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
struct lockInfo *pLock = pFile->pLock;
struct flock lock;
int s;
assert( pFile );
OSTRACE7("LOCK %d %s was %s(%s,%d) pid=%d\n", pFile->h,
locktypeName(locktype), locktypeName(pFile->locktype),
locktypeName(pLock->locktype), pLock->cnt , getpid());
/* If there is already a lock of this type or more restrictive on the
** unixFile, do nothing. Don't use the end_lock: exit path, as
** enterMutex() hasn't been called yet.
*/
if( pFile->locktype>=locktype ){
OSTRACE3("LOCK %d %s ok (already held)\n", pFile->h,
locktypeName(locktype));
return SQLITE_OK;
}
/* Make sure the locking sequence is correct
*/
assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
assert( locktype!=PENDING_LOCK );
assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
/* This mutex is needed because pFile->pLock is shared across threads
*/
enterMutex();
/* Make sure the current thread owns the pFile.
*/
rc = transferOwnership(pFile);
if( rc!=SQLITE_OK ){
leaveMutex();
return rc;
}
pLock = pFile->pLock;
/* If some thread using this PID has a lock via a different unixFile*
** handle that precludes the requested lock, return BUSY.
*/
if( (pFile->locktype!=pLock->locktype &&
(pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
){
rc = SQLITE_BUSY;
goto end_lock;
}
/* If a SHARED lock is requested, and some thread using this PID already
** has a SHARED or RESERVED lock, then increment reference counts and
** return SQLITE_OK.
*/
if( locktype==SHARED_LOCK &&
(pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
assert( locktype==SHARED_LOCK );
assert( pFile->locktype==0 );
assert( pLock->cnt>0 );
pFile->locktype = SHARED_LOCK;
pLock->cnt++;
pFile->pOpen->nLock++;
goto end_lock;
}
lock.l_len = 1L;
lock.l_whence = SEEK_SET;
/* A PENDING lock is needed before acquiring a SHARED lock and before
** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will
** be released.
*/
if( locktype==SHARED_LOCK
|| (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
){
lock.l_type = (locktype==SHARED_LOCK?F_RDLCK:F_WRLCK);
lock.l_start = PENDING_BYTE;
s = fcntl(pFile->h, F_SETLK, &lock);
if( s==(-1) ){
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
goto end_lock;
}
}
/* If control gets to this point, then actually go ahead and make
** operating system calls for the specified lock.
*/
if( locktype==SHARED_LOCK ){
int tErrno = 0;
assert( pLock->cnt==0 );
assert( pLock->locktype==0 );
/* Now get the read-lock */
lock.l_start = SHARED_FIRST;
lock.l_len = SHARED_SIZE;
if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
tErrno = errno;
}
/* Drop the temporary PENDING lock */
lock.l_start = PENDING_BYTE;
lock.l_len = 1L;
lock.l_type = F_UNLCK;
if( fcntl(pFile->h, F_SETLK, &lock)!=0 ){
if( s != -1 ){
/* This could happen with a network mount */
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
goto end_lock;
}
}
if( s==(-1) ){
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
}else{
pFile->locktype = SHARED_LOCK;
pFile->pOpen->nLock++;
pLock->cnt = 1;
}
}else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
/* We are trying for an exclusive lock but another thread in this
** same process is still holding a shared lock. */
rc = SQLITE_BUSY;
}else{
/* The request was for a RESERVED or EXCLUSIVE lock. It is
** assumed that there is a SHARED or greater lock on the file
** already.
*/
assert( 0!=pFile->locktype );
lock.l_type = F_WRLCK;
switch( locktype ){
case RESERVED_LOCK:
lock.l_start = RESERVED_BYTE;
break;
case EXCLUSIVE_LOCK:
lock.l_start = SHARED_FIRST;
lock.l_len = SHARED_SIZE;
break;
default:
assert(0);
}
s = fcntl(pFile->h, F_SETLK, &lock);
if( s==(-1) ){
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
}
}
if( rc==SQLITE_OK ){
pFile->locktype = locktype;
pLock->locktype = locktype;
}else if( locktype==EXCLUSIVE_LOCK ){
pFile->locktype = PENDING_LOCK;
pLock->locktype = PENDING_LOCK;
}
end_lock:
leaveMutex();
OSTRACE4("LOCK %d %s %s\n", pFile->h, locktypeName(locktype),
rc==SQLITE_OK ? "ok" : "failed");
return rc;
}
/*
** Lower the locking level on file descriptor pFile to locktype. locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(sqlite3_file *id, int locktype){
struct lockInfo *pLock;
struct flock lock;
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
int h;
assert( pFile );
OSTRACE7("UNLOCK %d %d was %d(%d,%d) pid=%d\n", pFile->h, locktype,
pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());
assert( locktype<=SHARED_LOCK );
if( pFile->locktype<=locktype ){
return SQLITE_OK;
}
if( CHECK_THREADID(pFile) ){
return SQLITE_MISUSE;
}
enterMutex();
h = pFile->h;
pLock = pFile->pLock;
assert( pLock->cnt!=0 );
if( pFile->locktype>SHARED_LOCK ){
assert( pLock->locktype==pFile->locktype );
SimulateIOErrorBenign(1);
SimulateIOError( h=(-1) )
SimulateIOErrorBenign(0);
if( locktype==SHARED_LOCK ){
lock.l_type = F_RDLCK;
lock.l_whence = SEEK_SET;
lock.l_start = SHARED_FIRST;
lock.l_len = SHARED_SIZE;
if( fcntl(h, F_SETLK, &lock)==(-1) ){
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
goto end_unlock;
}
}
lock.l_type = F_UNLCK;
lock.l_whence = SEEK_SET;
lock.l_start = PENDING_BYTE;
lock.l_len = 2L; assert( PENDING_BYTE+1==RESERVED_BYTE );
if( fcntl(h, F_SETLK, &lock)!=(-1) ){
pLock->locktype = SHARED_LOCK;
}else{
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
goto end_unlock;
}
}
if( locktype==NO_LOCK ){
struct openCnt *pOpen;
/* Decrement the shared lock counter. Release the lock using an
** OS call only when all threads in this same process have released
** the lock.
*/
pLock->cnt--;
if( pLock->cnt==0 ){
lock.l_type = F_UNLCK;
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0L;
SimulateIOErrorBenign(1);
SimulateIOError( h=(-1) )
SimulateIOErrorBenign(0);
if( fcntl(h, F_SETLK, &lock)!=(-1) ){
pLock->locktype = NO_LOCK;
}else{
int tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
pLock->cnt = 1;
goto end_unlock;
}
}
/* Decrement the count of locks against this same file. When the
** count reaches zero, close any other file descriptors whose close
** was deferred because of outstanding locks.
*/
if( rc==SQLITE_OK ){
pOpen = pFile->pOpen;
pOpen->nLock--;
assert( pOpen->nLock>=0 );
if( pOpen->nLock==0 && pOpen->nPending>0 ){
int i;
for(i=0; i<pOpen->nPending; i++){
close(pOpen->aPending[i]);
}
sqlite3_free(pOpen->aPending);
pOpen->nPending = 0;
pOpen->aPending = 0;
}
}
}
end_unlock:
leaveMutex();
if( rc==SQLITE_OK ) pFile->locktype = locktype;
return rc;
}
/*
** This function performs the parts of the "close file" operation
** common to all locking schemes. It closes the directory and file
** handles, if they are valid, and sets all fields of the unixFile
** structure to 0.
*/
static int closeUnixFile(sqlite3_file *id){
unixFile *pFile = (unixFile*)id;
if( pFile ){
if( pFile->dirfd>=0 ){
close(pFile->dirfd);
}
if( pFile->h>=0 ){
close(pFile->h);
}
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( pFile->isDelete && pFile->zRealpath ){
unlink(pFile->zRealpath);
}
if( pFile->zRealpath ){
HashElem *pElem;
int n = strlen(pFile->zRealpath) + 1;
pElem = sqlite3HashFindElem(&nameHash, pFile->zRealpath, n);
if( pElem ){
long cnt = (long)pElem->data;
cnt--;
if( cnt==0 ){
sqlite3HashInsert(&nameHash, pFile->zRealpath, n, 0);
}else{
pElem->data = (void*)cnt;
}
}
}
#endif
OSTRACE2("CLOSE %-3d\n", pFile->h);
OpenCounter(-1);
memset(pFile, 0, sizeof(unixFile));
}
return SQLITE_OK;
}
/*
** Close a file.
*/
static int unixClose(sqlite3_file *id){
if( id ){
unixFile *pFile = (unixFile *)id;
unixUnlock(id, NO_LOCK);
enterMutex();
if( pFile->pOpen && pFile->pOpen->nLock ){
/* If there are outstanding locks, do not actually close the file just
** yet because that would clear those locks. Instead, add the file
** descriptor to pOpen->aPending. It will be automatically closed when
** the last lock is cleared.
*/
int *aNew;
struct openCnt *pOpen = pFile->pOpen;
aNew = sqlite3_realloc(pOpen->aPending, (pOpen->nPending+1)*sizeof(int) );
if( aNew==0 ){
/* If a malloc fails, just leak the file descriptor */
}else{
pOpen->aPending = aNew;
pOpen->aPending[pOpen->nPending] = pFile->h;
pOpen->nPending++;
pFile->h = -1;
}
}
releaseLockInfo(pFile->pLock);
releaseOpenCnt(pFile->pOpen);
closeUnixFile(id);
leaveMutex();
}
return SQLITE_OK;
}
#if SQLITE_ENABLE_LOCKING_STYLE
#if !defined(__RTP__) && !defined(_WRS_KERNEL)
#pragma mark AFP Support
/*
** The afpLockingContext structure contains all afp lock specific state
*/
typedef struct afpLockingContext afpLockingContext;
struct afpLockingContext {
unsigned long long sharedLockByte;
const char *filePath;
};
struct ByteRangeLockPB2
{
unsigned long long offset; /* offset to first byte to lock */
unsigned long long length; /* nbr of bytes to lock */
unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */
unsigned char unLockFlag; /* 1 = unlock, 0 = lock */
unsigned char startEndFlag; /* 1=rel to end of fork, 0=rel to start */
int fd; /* file desc to assoc this lock with */
};
#define afpfsByteRangeLock2FSCTL _IOWR('z', 23, struct ByteRangeLockPB2)
/*
** Return SQLITE_OK on success, SQLITE_BUSY on failure.
*/
static int _AFPFSSetLock(
const char *path,
unixFile *pFile,
unsigned long long offset,
unsigned long long length,
int setLockFlag
){
struct ByteRangeLockPB2 pb;
int err;
pb.unLockFlag = setLockFlag ? 0 : 1;
pb.startEndFlag = 0;
pb.offset = offset;
pb.length = length;
pb.fd = pFile->h;
OSTRACE5("AFPLOCK setting lock %s for %d in range %llx:%llx\n",
(setLockFlag?"ON":"OFF"), pFile->h, offset, length);
err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
if ( err==-1 ) {
int rc;
int tErrno = errno;
OSTRACE4("AFPLOCK failed to fsctl() '%s' %d %s\n", path, tErrno, strerror(tErrno));
rc = sqliteErrorFromPosixError(tErrno, setLockFlag ? SQLITE_IOERR_LOCK : SQLITE_IOERR_UNLOCK); /* error */
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
return rc;
} else {
return SQLITE_OK;
}
}
/* AFP-style reserved lock checking following the behavior of
** unixCheckReservedLock, see the unixCheckReservedLock function comments */
static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){
int rc = SQLITE_OK;
int reserved = 0;
unixFile *pFile = (unixFile*)id;
SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
assert( pFile );
afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
/* Check if a thread in this process holds such a lock */
if( pFile->locktype>SHARED_LOCK ){
reserved = 1;
}
/* Otherwise see if some other process holds it.
*/
if( !reserved ){
/* lock the RESERVED byte */
int lrc = _AFPFSSetLock(context->filePath, pFile, RESERVED_BYTE, 1,1);
if( SQLITE_OK==lrc ){
/* if we succeeded in taking the reserved lock, unlock it to restore
** the original state */
lrc = _AFPFSSetLock(context->filePath, pFile, RESERVED_BYTE, 1, 0);
} else {
/* if we failed to get the lock then someone else must have it */
reserved = 1;
}
if( IS_LOCK_ERROR(lrc) ){
rc=lrc;
}
}
OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
*pResOut = reserved;
return rc;
}
/* AFP-style locking following the behavior of unixLock, see the unixLock
** function comments for details of lock management. */
static int afpLock(sqlite3_file *id, int locktype){
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
assert( pFile );
OSTRACE5("LOCK %d %s was %s pid=%d\n", pFile->h,
locktypeName(locktype), locktypeName(pFile->locktype), getpid());
/* If there is already a lock of this type or more restrictive on the
** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
** enterMutex() hasn't been called yet.
*/
if( pFile->locktype>=locktype ){
OSTRACE3("LOCK %d %s ok (already held)\n", pFile->h,
locktypeName(locktype));
return SQLITE_OK;
}
/* Make sure the locking sequence is correct
*/
assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
assert( locktype!=PENDING_LOCK );
assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
/* This mutex is needed because pFile->pLock is shared across threads
*/
enterMutex();
/* Make sure the current thread owns the pFile.
*/
rc = transferOwnership(pFile);
if( rc!=SQLITE_OK ){
leaveMutex();
return rc;
}
/* A PENDING lock is needed before acquiring a SHARED lock and before
** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will
** be released.
*/
if( locktype==SHARED_LOCK
|| (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
){
int failed;
failed = _AFPFSSetLock(context->filePath, pFile, PENDING_BYTE, 1, 1);
if (failed) {
rc = failed;
goto afp_end_lock;
}
}
/* If control gets to this point, then actually go ahead and make
** operating system calls for the specified lock.
*/
if( locktype==SHARED_LOCK ){
int lk, lrc1, lrc2, lrc1Errno;
/* Now get the read-lock SHARED_LOCK */
/* note that the quality of the randomness doesn't matter that much */
lk = random();
context->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
lrc1 = _AFPFSSetLock(context->filePath, pFile,
SHARED_FIRST+context->sharedLockByte, 1, 1);
if( IS_LOCK_ERROR(lrc1) ){
lrc1Errno = pFile->lastErrno;
}
/* Drop the temporary PENDING lock */
lrc2 = _AFPFSSetLock(context->filePath, pFile, PENDING_BYTE, 1, 0);
if( IS_LOCK_ERROR(lrc1) ) {
pFile->lastErrno = lrc1Errno;
rc = lrc1;
goto afp_end_lock;
} else if( IS_LOCK_ERROR(lrc2) ){
rc = lrc2;
goto afp_end_lock;
} else if( lrc1 != SQLITE_OK ) {
rc = lrc1;
} else {
pFile->locktype = SHARED_LOCK;
}
}else{
/* The request was for a RESERVED or EXCLUSIVE lock. It is
** assumed that there is a SHARED or greater lock on the file
** already.
*/
int failed = 0;
assert( 0!=pFile->locktype );
if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
/* Acquire a RESERVED lock */
failed = _AFPFSSetLock(context->filePath, pFile, RESERVED_BYTE, 1,1);
}
if (!failed && locktype == EXCLUSIVE_LOCK) {
/* Acquire an EXCLUSIVE lock */
/* Remove the shared lock before trying the range. we'll need to
** reestablish the shared lock if we can't get the afpUnlock
*/
if (!(failed = _AFPFSSetLock(context->filePath, pFile, SHARED_FIRST +
context->sharedLockByte, 1, 0))) {
/* now attemmpt to get the exclusive lock range */
failed = _AFPFSSetLock(context->filePath, pFile, SHARED_FIRST,
SHARED_SIZE, 1);
if (failed && (failed = _AFPFSSetLock(context->filePath, pFile,
SHARED_FIRST + context->sharedLockByte, 1, 1))) {
rc = failed;
}
} else {
rc = failed;
}
}
if( failed ){
rc = failed;
}
}
if( rc==SQLITE_OK ){
pFile->locktype = locktype;
}else if( locktype==EXCLUSIVE_LOCK ){
pFile->locktype = PENDING_LOCK;
}
afp_end_lock:
leaveMutex();
OSTRACE4("LOCK %d %s %s\n", pFile->h, locktypeName(locktype),
rc==SQLITE_OK ? "ok" : "failed");
return rc;
}
/*
** Lower the locking level on file descriptor pFile to locktype. locktype
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
*/
static int afpUnlock(sqlite3_file *id, int locktype) {
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
assert( pFile );
OSTRACE5("UNLOCK %d %d was %d pid=%d\n", pFile->h, locktype,
pFile->locktype, getpid());
assert( locktype<=SHARED_LOCK );
if( pFile->locktype<=locktype ){
return SQLITE_OK;
}
if( CHECK_THREADID(pFile) ){
return SQLITE_MISUSE;
}
enterMutex();
int failed = SQLITE_OK;
if( pFile->locktype>SHARED_LOCK ){
if( locktype==SHARED_LOCK ){
/* unlock the exclusive range - then re-establish the shared lock */
if (pFile->locktype==EXCLUSIVE_LOCK) {
failed = _AFPFSSetLock(context->filePath, pFile, SHARED_FIRST,
SHARED_SIZE, 0);
if (!failed) {
/* successfully removed the exclusive lock */
if ((failed = _AFPFSSetLock(context->filePath, pFile, SHARED_FIRST+
context->sharedLockByte, 1, 1))) {
/* failed to re-establish our shared lock */
rc = failed;
}
} else {
rc = failed;
}
}
}
if (rc == SQLITE_OK && pFile->locktype>=PENDING_LOCK) {
if ((failed = _AFPFSSetLock(context->filePath, pFile,
PENDING_BYTE, 1, 0))){
/* failed to release the pending lock */
rc = failed;
}
}
if (rc == SQLITE_OK && pFile->locktype>=RESERVED_LOCK) {
if ((failed = _AFPFSSetLock(context->filePath, pFile,
RESERVED_BYTE, 1, 0))) {
/* failed to release the reserved lock */
rc = failed;
}
}
}
if( locktype==NO_LOCK ){
int failed = _AFPFSSetLock(context->filePath, pFile,
SHARED_FIRST + context->sharedLockByte, 1, 0);
if (failed) {
rc = failed;
}
}
if (rc == SQLITE_OK)
pFile->locktype = locktype;
leaveMutex();
return rc;
}
/*
** Close a file & cleanup AFP specific locking context
*/
static int afpClose(sqlite3_file *id) {
if( id ){
unixFile *pFile = (unixFile*)id;
afpUnlock(id, NO_LOCK);
sqlite3_free(pFile->lockingContext);
}
return closeUnixFile(id);
}
#pragma mark flock() style locking
/*
** The flockLockingContext is not used
*/
typedef void flockLockingContext;
/* flock-style reserved lock checking following the behavior of
** unixCheckReservedLock, see the unixCheckReservedLock function comments */
static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){
int rc = SQLITE_OK;
int reserved = 0;
unixFile *pFile = (unixFile*)id;
SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
assert( pFile );
/* Check if a thread in this process holds such a lock */
if( pFile->locktype>SHARED_LOCK ){
reserved = 1;
}
/* Otherwise see if some other process holds it. */
if( !reserved ){
/* attempt to get the lock */
int lrc = flock(pFile->h, LOCK_EX | LOCK_NB);
if( !lrc ){
/* got the lock, unlock it */
lrc = flock(pFile->h, LOCK_UN);
if ( lrc ) {
int tErrno = errno;
/* unlock failed with an error */
lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(lrc) ){
pFile->lastErrno = tErrno;
rc = lrc;
}
}
} else {
int tErrno = errno;
reserved = 1;
/* someone else might have it reserved */
lrc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(lrc) ){
pFile->lastErrno = tErrno;
rc = lrc;
}
}
}
OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
*pResOut = reserved;
return rc;
}
static int flockLock(sqlite3_file *id, int locktype) {
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
assert( pFile );
/* if we already have a lock, it is exclusive.
** Just adjust level and punt on outta here. */
if (pFile->locktype > NO_LOCK) {
pFile->locktype = locktype;
return SQLITE_OK;
}
/* grab an exclusive lock */
if (flock(pFile->h, LOCK_EX | LOCK_NB)) {
int tErrno = errno;
/* didn't get, must be busy */
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
} else {
/* got it, set the type and return ok */
pFile->locktype = locktype;
}
OSTRACE4("LOCK %d %s %s\n", pFile->h, locktypeName(locktype),
rc==SQLITE_OK ? "ok" : "failed");
return rc;
}
static int flockUnlock(sqlite3_file *id, int locktype) {
unixFile *pFile = (unixFile*)id;
assert( pFile );
OSTRACE5("UNLOCK %d %d was %d pid=%d\n", pFile->h, locktype,
pFile->locktype, getpid());
assert( locktype<=SHARED_LOCK );
/* no-op if possible */
if( pFile->locktype==locktype ){
return SQLITE_OK;
}
/* shared can just be set because we always have an exclusive */
if (locktype==SHARED_LOCK) {
pFile->locktype = locktype;
return SQLITE_OK;
}
/* no, really, unlock. */
int rc = flock(pFile->h, LOCK_UN);
if (rc) {
int r, tErrno = errno;
r = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(r) ){
pFile->lastErrno = tErrno;
}
return r;
} else {
pFile->locktype = NO_LOCK;
return SQLITE_OK;
}
}
/*
** Close a file.
*/
static int flockClose(sqlite3_file *id) {
if( id ){
flockUnlock(id, NO_LOCK);
}
return closeUnixFile(id);
}
#endif /* !defined(__RTP__) && !defined(_WRS_KERNEL) */
#pragma mark Old-School .lock file based locking
/* Dotlock-style reserved lock checking following the behavior of
** unixCheckReservedLock, see the unixCheckReservedLock function comments */
static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) {
int rc = SQLITE_OK;
int reserved = 0;
unixFile *pFile = (unixFile*)id;
SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
assert( pFile );
/* Check if a thread in this process holds such a lock */
if( pFile->locktype>SHARED_LOCK ){
reserved = 1;
}
/* Otherwise see if some other process holds it. */
if( !reserved ){
char *zLockFile = (char *)pFile->lockingContext;
struct stat statBuf;
if( lstat(zLockFile, &statBuf)==0 ){
/* file exists, someone else has the lock */
reserved = 1;
}else{
/* file does not exist, we could have it if we want it */
int tErrno = errno;
if( ENOENT != tErrno ){
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
pFile->lastErrno = tErrno;
}
}
}
OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
*pResOut = reserved;
return rc;
}
static int dotlockLock(sqlite3_file *id, int locktype) {
unixFile *pFile = (unixFile*)id;
int fd;
char *zLockFile = (char *)pFile->lockingContext;
int rc=SQLITE_OK;
/* if we already have a lock, it is exclusive.
** Just adjust level and punt on outta here. */
if (pFile->locktype > NO_LOCK) {
pFile->locktype = locktype;
#if !defined(__RTP__) && !defined(_WRS_KERNEL)
/* Always update the timestamp on the old file */
utimes(zLockFile, NULL);
#endif
rc = SQLITE_OK;
goto dotlock_end_lock;
}
/* check to see if lock file already exists */
struct stat statBuf;
if (lstat(zLockFile,&statBuf) == 0){
rc = SQLITE_BUSY; /* it does, busy */
goto dotlock_end_lock;
}
/* grab an exclusive lock */
fd = open(zLockFile,O_RDONLY|O_CREAT|O_EXCL,0600);
if( fd<0 ){
/* failed to open/create the file, someone else may have stolen the lock */
int tErrno = errno;
if( EEXIST == tErrno ){
rc = SQLITE_BUSY;
} else {
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
}
goto dotlock_end_lock;
}
close(fd);
/* got it, set the type and return ok */
pFile->locktype = locktype;
dotlock_end_lock:
return rc;
}
static int dotlockUnlock(sqlite3_file *id, int locktype) {
unixFile *pFile = (unixFile*)id;
char *zLockFile = (char *)pFile->lockingContext;
assert( pFile );
OSTRACE5("UNLOCK %d %d was %d pid=%d\n", pFile->h, locktype,
pFile->locktype, getpid());
assert( locktype<=SHARED_LOCK );
/* no-op if possible */
if( pFile->locktype==locktype ){
return SQLITE_OK;
}
/* shared can just be set because we always have an exclusive */
if (locktype==SHARED_LOCK) {
pFile->locktype = locktype;
return SQLITE_OK;
}
/* no, really, unlock. */
if (unlink(zLockFile) ) {
int rc, tErrno = errno;
if( ENOENT != tErrno ){
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
}
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
return rc;
}
pFile->locktype = NO_LOCK;
return SQLITE_OK;
}
/*
** Close a file.
*/
static int dotlockClose(sqlite3_file *id) {
#if defined(__RTP__) || defined(_WRS_KERNEL)
int rc;
#endif
if( id ){
unixFile *pFile = (unixFile*)id;
dotlockUnlock(id, NO_LOCK);
sqlite3_free(pFile->lockingContext);
}
#if defined(__RTP__) || defined(_WRS_KERNEL)
enterMutex();
rc = closeUnixFile(id);
leaveMutex();
return rc;
#else
return closeUnixFile(id);
#endif
}
#if defined(__RTP__) || defined(_WRS_KERNEL)
#pragma mark POSIX/vxWorks named semaphore based locking
/* Namedsem-style reserved lock checking following the behavior of
** unixCheckReservedLock, see the unixCheckReservedLock function comments */
static int namedsemCheckReservedLock(sqlite3_file *id, int *pResOut) {
int rc = SQLITE_OK;
int reserved = 0;
unixFile *pFile = (unixFile*)id;
SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );
assert( pFile );
/* Check if a thread in this process holds such a lock */
if( pFile->locktype>SHARED_LOCK ){
reserved = 1;
}
/* Otherwise see if some other process holds it. */
if( !reserved ){
sem_t *pSem = pFile->pOpen->pSem;
struct stat statBuf;
if( sem_trywait(pSem)==-1 ){
int tErrno = errno;
if( EAGAIN != tErrno ){
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_CHECKRESERVEDLOCK);
pFile->lastErrno = tErrno;
} else {
/* someone else has the lock when we are in NO_LOCK */
reserved = (pFile->locktype < SHARED_LOCK);
}
}else{
/* we could have it if we want it */
sem_post(pSem);
}
}
OSTRACE4("TEST WR-LOCK %d %d %d\n", pFile->h, rc, reserved);
*pResOut = reserved;
return rc;
}
static int namedsemLock(sqlite3_file *id, int locktype) {
unixFile *pFile = (unixFile*)id;
int fd;
sem_t *pSem = pFile->pOpen->pSem;
int rc = SQLITE_OK;
/* if we already have a lock, it is exclusive.
** Just adjust level and punt on outta here. */
if (pFile->locktype > NO_LOCK) {
pFile->locktype = locktype;
rc = SQLITE_OK;
goto namedsem_end_lock;
}
/* lock semaphore now but bail out when already locked. */
if( sem_trywait(pSem)==-1 ){
rc = SQLITE_BUSY;
goto namedsem_end_lock;
}
/* got it, set the type and return ok */
pFile->locktype = locktype;
namedsem_end_lock:
return rc;
}
static int namedsemUnlock(sqlite3_file *id, int locktype) {
unixFile *pFile = (unixFile*)id;
sem_t *pSem = pFile->pOpen->pSem;
assert( pFile );
assert( pSem );
OSTRACE5("UNLOCK %d %d was %d pid=%d\n", pFile->h, locktype,
pFile->locktype, getpid());
assert( locktype<=SHARED_LOCK );
/* no-op if possible */
if( pFile->locktype==locktype ){
return SQLITE_OK;
}
/* shared can just be set because we always have an exclusive */
if (locktype==SHARED_LOCK) {
pFile->locktype = locktype;
return SQLITE_OK;
}
/* no, really unlock. */
if ( sem_post(pSem)==-1 ) {
int rc, tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
return rc;
}
pFile->locktype = NO_LOCK;
return SQLITE_OK;
}
/*
** Close a file.
*/
static int namedsemClose(sqlite3_file *id) {
if( id ){
unixFile *pFile = (unixFile*)id;
namedsemUnlock(id, NO_LOCK);
assert( pFile );
enterMutex();
releaseLockInfo(pFile->pLock);
releaseOpenCnt(pFile->pOpen);
closeUnixFile(id);
leaveMutex();
}
return SQLITE_OK;
}
#endif /* defined(__RTP__) || defined(_WRS_KERNEL) */
#endif /* SQLITE_ENABLE_LOCKING_STYLE */
/*
** The nolockLockingContext is void
*/
typedef void nolockLockingContext;
static int nolockCheckReservedLock(sqlite3_file *id, int *pResOut) {
*pResOut = 0;
return SQLITE_OK;
}
static int nolockLock(sqlite3_file *id, int locktype) {
return SQLITE_OK;
}
static int nolockUnlock(sqlite3_file *id, int locktype) {
return SQLITE_OK;
}
/*
** Close a file.
*/
static int nolockClose(sqlite3_file *id) {
#if defined(__RTP__) || defined(_WRS_KERNEL)
int rc;
enterMutex();
rc = closeUnixFile(id);
leaveMutex();
return rc;
#else
return closeUnixFile(id);
#endif
}
/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
switch( op ){
case SQLITE_FCNTL_LOCKSTATE: {
*(int*)pArg = ((unixFile*)id)->locktype;
return SQLITE_OK;
}
}
return SQLITE_ERROR;
}
/*
** Return the sector size in bytes of the underlying block device for
** the specified file. This is almost always 512 bytes, but may be
** larger for some devices.
**
** SQLite code assumes this function cannot fail. It also assumes that
** if two files are created in the same file-system directory (i.e.
** a database and its journal file) that the sector size will be the
** same for both.
*/
static int unixSectorSize(sqlite3_file *id){
return SQLITE_DEFAULT_SECTOR_SIZE;
}
/*
** Return the device characteristics for the file. This is always 0.
*/
static int unixDeviceCharacteristics(sqlite3_file *id){
return 0;
}
/*
** Initialize the contents of the unixFile structure pointed to by pId.
**
** When locking extensions are enabled, the filepath and locking style
** are needed to determine the unixFile pMethod to use for locking operations.
** The locking-style specific lockingContext data structure is created
** and assigned here also.
*/
static int fillInUnixFile(
sqlite3_vfs *pVfs, /* Pointer to vfs object */
int h, /* Open file descriptor of file being opened */
int dirfd, /* Directory file descriptor */
sqlite3_file *pId, /* Write to the unixFile structure here */
const char *zFilename, /* Name of the file being opened */
int noLock, /* Omit locking if true */
int isDelete /* Delete on close if true */
){
int eLockingStyle;
unixFile *pNew = (unixFile *)pId;
int rc = SQLITE_OK;
/* Macro to define the static contents of an sqlite3_io_methods
** structure for a unix backend file. Different locking methods
** require different functions for the xClose, xLock, xUnlock and
** xCheckReservedLock methods.
*/
#define IOMETHODS(xClose, xLock, xUnlock, xCheckReservedLock) { \
1, /* iVersion */ \
xClose, /* xClose */ \
unixRead, /* xRead */ \
unixWrite, /* xWrite */ \
unixTruncate, /* xTruncate */ \
unixSync, /* xSync */ \
unixFileSize, /* xFileSize */ \
xLock, /* xLock */ \
xUnlock, /* xUnlock */ \
xCheckReservedLock, /* xCheckReservedLock */ \
unixFileControl, /* xFileControl */ \
unixSectorSize, /* xSectorSize */ \
unixDeviceCharacteristics /* xDeviceCapabilities */ \
}
static sqlite3_io_methods aIoMethod[] = {
IOMETHODS(unixClose, unixLock, unixUnlock, unixCheckReservedLock)
,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
#if SQLITE_ENABLE_LOCKING_STYLE
,IOMETHODS(dotlockClose, dotlockLock, dotlockUnlock,dotlockCheckReservedLock)
#if defined(__RTP__) || defined(_WRS_KERNEL)
,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
,IOMETHODS(namedsemClose, namedsemLock, namedsemUnlock, namedsemCheckReservedLock)
#else
,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock)
,IOMETHODS(afpClose, afpLock, afpUnlock, afpCheckReservedLock)
,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
#endif
#endif
};
/* The order of the IOMETHODS macros above is important. It must be the
** same order as the LOCKING_STYLE numbers
*/
assert(LOCKING_STYLE_POSIX==1);
assert(LOCKING_STYLE_NONE==2);
assert(LOCKING_STYLE_DOTFILE==3);
assert(LOCKING_STYLE_FLOCK==4);
assert(LOCKING_STYLE_AFP==5);
assert(LOCKING_STYLE_NAMEDSEM==6);
assert( pNew->pLock==NULL );
assert( pNew->pOpen==NULL );
OSTRACE3("OPEN %-3d %s\n", h, zFilename);
pNew->h = h;
pNew->dirfd = dirfd;
SET_THREADID(pNew);
#if defined(__RTP__) || defined(_WRS_KERNEL)
{
HashElem *pElem;
char *zRealname = vxrealpath(zFilename, 1);
int n;
pNew->zRealpath = 0;
if( !zRealname ){
rc = SQLITE_NOMEM;
eLockingStyle = LOCKING_STYLE_NONE;
}else{
n = strlen(zRealname) + 1;
enterMutex();
pElem = sqlite3HashFindElem(&nameHash, zRealname, n);
if( pElem ){
long cnt = (long)pElem->data;
cnt++;
pNew->zRealpath = pElem->pKey;
pElem->data = (void*)cnt;
}else{
if( sqlite3HashInsert(&nameHash, zRealname, n, (void*)1)==0 ){
pElem = sqlite3HashFindElem(&nameHash, zRealname, n);
if( pElem ){
pNew->zRealpath = pElem->pKey;
}else{
sqlite3HashInsert(&nameHash, zRealname, n, 0);
rc = SQLITE_NOMEM;
eLockingStyle = LOCKING_STYLE_NONE;
}
}
}
leaveMutex();
sqlite3_free(zRealname);
}
}
#endif
if( noLock ){
eLockingStyle = LOCKING_STYLE_NONE;
}else{
eLockingStyle = detectLockingStyle(pVfs, zFilename, h);
}
switch( eLockingStyle ){
case LOCKING_STYLE_POSIX: {
enterMutex();
#if defined(__RTP__) || defined(_WRS_KERNEL)
rc = findLockInfo(h, pNew->zRealpath, &pNew->pLock, &pNew->pOpen);
#else
rc = findLockInfo(h, &pNew->pLock, &pNew->pOpen);
#endif
leaveMutex();
break;
}
#if SQLITE_ENABLE_LOCKING_STYLE
#if !defined(__RTP__) && !defined(_WRS_KERNEL)
case LOCKING_STYLE_AFP: {
/* AFP locking uses the file path so it needs to be included in
** the afpLockingContext.
*/
afpLockingContext *pCtx;
pNew->lockingContext = pCtx = sqlite3_malloc( sizeof(*pCtx) );
if( pCtx==0 ){
rc = SQLITE_NOMEM;
}else{
/* NB: zFilename exists and remains valid until the file is closed
** according to requirement F11141. So we do not need to make a
** copy of the filename. */
pCtx->filePath = zFilename;
srandomdev();
}
break;
}
#endif
case LOCKING_STYLE_DOTFILE: {
/* Dotfile locking uses the file path so it needs to be included in
** the dotlockLockingContext
*/
char *zLockFile;
int nFilename;
nFilename = strlen(zFilename) + 6;
zLockFile = (char *)sqlite3_malloc(nFilename);
if( zLockFile==0 ){
rc = SQLITE_NOMEM;
}else{
sqlite3_snprintf(nFilename, zLockFile, "%s.lock", zFilename);
}
pNew->lockingContext = zLockFile;
break;
}
#if defined(__RTP__) || defined(_WRS_KERNEL)
case LOCKING_STYLE_NAMEDSEM: {
/* Named semaphore locking uses the file path so it needs to be
** included in the namedsemLockingContext
*/
enterMutex();
rc = findLockInfo(h, pNew->zRealpath, &pNew->pLock, &pNew->pOpen);
if( (rc==SQLITE_OK) && (pNew->pOpen->pSem==NULL) ){
char *zSemName = pNew->pOpen->aSemName;
int n;
sqlite3_snprintf(MAX_PATHNAME, zSemName, "%s.sem", pNew->zRealpath);
for( n=0; zSemName[n]; n++ )
if( zSemName[n]=='/' ) zSemName[n] = '_';
pNew->pOpen->pSem = sem_open(zSemName, O_CREAT, 0666, 1);
if( pNew->pOpen->pSem == SEM_FAILED ){
rc = SQLITE_NOMEM;
pNew->pOpen->aSemName[0] = '\0';
}
}
leaveMutex();
break;
}
#endif
#if !defined(__RTP__) && !defined(_WRS_KERNEL)
case LOCKING_STYLE_FLOCK:
#endif
case LOCKING_STYLE_NONE:
break;
#endif
}
pNew->lastErrno = 0;
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( rc!=SQLITE_OK ){
unlink(zFilename);
isDelete = 0;
}
pNew->isDelete = isDelete;
#endif
if( rc!=SQLITE_OK ){
if( dirfd>=0 ) close(dirfd);
close(h);
}else{
pNew->pMethod = &aIoMethod[eLockingStyle-1];
OpenCounter(+1);
}
return rc;
}
/*
** Open a file descriptor to the directory containing file zFilename.
** If successful, *pFd is set to the opened file descriptor and
** SQLITE_OK is returned. If an error occurs, either SQLITE_NOMEM
** or SQLITE_CANTOPEN is returned and *pFd is set to an undefined
** value.
**
** If SQLITE_OK is returned, the caller is responsible for closing
** the file descriptor *pFd using close().
*/
static int openDirectory(const char *zFilename, int *pFd){
int ii;
int fd = -1;
char zDirname[MAX_PATHNAME+1];
sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
for(ii=strlen(zDirname); ii>=0 && zDirname[ii]!='/'; ii--);
if( ii>0 ){
zDirname[ii] = '\0';
fd = open(zDirname, O_RDONLY|O_BINARY, 0);
if( fd>=0 ){
#ifdef FD_CLOEXEC
fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
OSTRACE3("OPENDIR %-3d %s\n", fd, zDirname);
}
}
*pFd = fd;
return (fd>=0?SQLITE_OK:SQLITE_CANTOPEN);
}
/*
** Create a temporary file name in zBuf. zBuf must be allocated
** by the calling process and must be big enough to hold at least
** pVfs->mxPathname bytes.
*/
static int getTempname(int nBuf, char *zBuf){
static const char *azDirs[] = {
0,
"/var/tmp",
"/usr/tmp",
"/tmp",
".",
};
static const unsigned char zChars[] =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789";
int i, j;
struct stat buf;
const char *zDir = ".";
/* It's odd to simulate an io-error here, but really this is just
** using the io-error infrastructure to test that SQLite handles this
** function failing.
*/
SimulateIOError( return SQLITE_IOERR );
azDirs[0] = sqlite3_temp_directory;
for(i=0; i<ArraySize(azDirs); i++){
if( azDirs[i]==0 ) continue;
if( stat(azDirs[i], &buf) ) continue;
if( !S_ISDIR(buf.st_mode) ) continue;
if( access(azDirs[i], 07) ) continue;
zDir = azDirs[i];
break;
}
/* Check that the output buffer is large enough for the temporary file
** name. If it is not, return SQLITE_ERROR.
*/
if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 17) >= (size_t)nBuf ){
return SQLITE_ERROR;
}
do{
sqlite3_snprintf(nBuf-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
j = strlen(zBuf);
sqlite3_randomness(15, &zBuf[j]);
for(i=0; i<15; i++, j++){
zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
}
zBuf[j] = 0;
}while( access(zBuf,0)==0 );
return SQLITE_OK;
}
/*
** Open the file zPath.
**
** Previously, the SQLite OS layer used three functions in place of this
** one:
**
** sqlite3OsOpenReadWrite();
** sqlite3OsOpenReadOnly();
** sqlite3OsOpenExclusive();
**
** These calls correspond to the following combinations of flags:
**
** ReadWrite() -> (READWRITE | CREATE)
** ReadOnly() -> (READONLY)
** OpenExclusive() -> (READWRITE | CREATE | EXCLUSIVE)
**
** The old OpenExclusive() accepted a boolean argument - "delFlag". If
** true, the file was configured to be automatically deleted when the
** file handle closed. To achieve the same effect using this new
** interface, add the DELETEONCLOSE flag to those specified above for
** OpenExclusive().
*/
static int unixOpen(
sqlite3_vfs *pVfs,
const char *zPath,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
int fd = 0; /* File descriptor returned by open() */
int dirfd = -1; /* Directory file descriptor */
int oflags = 0; /* Flags to pass to open() */
int eType = flags&0xFFFFFF00; /* Type of file to open */
int noLock; /* True to omit locking primitives */
int isExclusive = (flags & SQLITE_OPEN_EXCLUSIVE);
int isDelete = (flags & SQLITE_OPEN_DELETEONCLOSE);
int isCreate = (flags & SQLITE_OPEN_CREATE);
int isReadonly = (flags & SQLITE_OPEN_READONLY);
int isReadWrite = (flags & SQLITE_OPEN_READWRITE);
/* If creating a master or main-file journal, this function will open
** a file-descriptor on the directory too. The first time unixSync()
** is called the directory file descriptor will be fsync()ed and close()d.
*/
int isOpenDirectory = (isCreate &&
(eType==SQLITE_OPEN_MASTER_JOURNAL || eType==SQLITE_OPEN_MAIN_JOURNAL)
);
/* If argument zPath is a NULL pointer, this function is required to open
** a temporary file. Use this buffer to store the file name in.
*/
char zTmpname[MAX_PATHNAME+1];
const char *zName = zPath;
/* Check the following statements are true:
**
** (a) Exactly one of the READWRITE and READONLY flags must be set, and
** (b) if CREATE is set, then READWRITE must also be set, and
** (c) if EXCLUSIVE is set, then CREATE must also be set.
** (d) if DELETEONCLOSE is set, then CREATE must also be set.
*/
assert((isReadonly==0 || isReadWrite==0) && (isReadWrite || isReadonly));
assert(isCreate==0 || isReadWrite);
assert(isExclusive==0 || isCreate);
assert(isDelete==0 || isCreate);
/* The main DB, main journal, and master journal are never automatically
** deleted
*/
assert( eType!=SQLITE_OPEN_MAIN_DB || !isDelete );
assert( eType!=SQLITE_OPEN_MAIN_JOURNAL || !isDelete );
assert( eType!=SQLITE_OPEN_MASTER_JOURNAL || !isDelete );
/* Assert that the upper layer has set one of the "file-type" flags. */
assert( eType==SQLITE_OPEN_MAIN_DB || eType==SQLITE_OPEN_TEMP_DB
|| eType==SQLITE_OPEN_MAIN_JOURNAL || eType==SQLITE_OPEN_TEMP_JOURNAL
|| eType==SQLITE_OPEN_SUBJOURNAL || eType==SQLITE_OPEN_MASTER_JOURNAL
|| eType==SQLITE_OPEN_TRANSIENT_DB
);
memset(pFile, 0, sizeof(unixFile));
if( !zName ){
int rc;
assert(isDelete && !isOpenDirectory);
rc = getTempname(MAX_PATHNAME+1, zTmpname);
if( rc!=SQLITE_OK ){
return rc;
}
zName = zTmpname;
}
if( isReadonly ) oflags |= O_RDONLY;
if( isReadWrite ) oflags |= O_RDWR;
if( isCreate ) oflags |= O_CREAT;
if( isExclusive ) oflags |= (O_EXCL|O_NOFOLLOW);
oflags |= (O_LARGEFILE|O_BINARY);
fd = open(zName, oflags, isDelete?0600:SQLITE_DEFAULT_FILE_PERMISSIONS);
OSTRACE4("OPENX %-3d %s 0%o\n", fd, zName, oflags);
if( fd<0 && errno!=EISDIR && isReadWrite && !isExclusive ){
/* Failed to open the file for read/write access. Try read-only. */
flags &= ~(SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE);
flags |= SQLITE_OPEN_READONLY;
return unixOpen(pVfs, zPath, pFile, flags, pOutFlags);
}
if( fd<0 ){
return SQLITE_CANTOPEN;
}
if( isDelete ){
#if defined(__RTP__) || defined(_WRS_KERNEL)
zPath = zName;
#else
unlink(zName);
#endif
}
if( pOutFlags ){
*pOutFlags = flags;
}
assert(fd!=0);
if( isOpenDirectory ){
int rc = openDirectory(zPath, &dirfd);
if( rc!=SQLITE_OK ){
close(fd);
return rc;
}
}
#ifdef FD_CLOEXEC
fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
noLock = eType!=SQLITE_OPEN_MAIN_DB;
return fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);
}
/*
** Delete the file at zPath. If the dirSync argument is true, fsync()
** the directory after deleting the file.
*/
static int unixDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
int rc = SQLITE_OK;
SimulateIOError(return SQLITE_IOERR_DELETE);
unlink(zPath);
#ifndef SQLITE_DISABLE_DIRSYNC
if( dirSync ){
int fd;
rc = openDirectory(zPath, &fd);
if( rc==SQLITE_OK ){
#if defined(__RTP__) || defined(_WRS_KERNEL)
if( fsync(fd)==-1 )
#else
if( fsync(fd) )
#endif
{
rc = SQLITE_IOERR_DIR_FSYNC;
}
close(fd);
}
}
#endif
return rc;
}
/*
** Test the existance of or access permissions of file zPath. The
** test performed depends on the value of flags:
**
** SQLITE_ACCESS_EXISTS: Return 1 if the file exists
** SQLITE_ACCESS_READWRITE: Return 1 if the file is read and writable.
** SQLITE_ACCESS_READONLY: Return 1 if the file is readable.
**
** Otherwise return 0.
*/
static int unixAccess(
sqlite3_vfs *pVfs,
const char *zPath,
int flags,
int *pResOut
){
int amode = 0;
SimulateIOError( return SQLITE_IOERR_ACCESS; );
switch( flags ){
case SQLITE_ACCESS_EXISTS:
amode = F_OK;
break;
case SQLITE_ACCESS_READWRITE:
amode = W_OK|R_OK;
break;
case SQLITE_ACCESS_READ:
amode = R_OK;
break;
default:
assert(!"Invalid flags argument");
}
*pResOut = (access(zPath, amode)==0);
return SQLITE_OK;
}
/*
** Turn a relative pathname into a full pathname. The relative path
** is stored as a nul-terminated string in the buffer pointed to by
** zPath.
**
** zOut points to a buffer of at least sqlite3_vfs.mxPathname bytes
** (in this case, MAX_PATHNAME bytes). The full-path is written to
** this buffer before returning.
*/
static int unixFullPathname(
sqlite3_vfs *pVfs, /* Pointer to vfs object */
const char *zPath, /* Possibly relative input path */
int nOut, /* Size of output buffer in bytes */
char *zOut /* Output buffer */
){
/* It's odd to simulate an io-error here, but really this is just
** using the io-error infrastructure to test that SQLite handles this
** function failing. This function could fail if, for example, the
** current working directly has been unlinked.
*/
SimulateIOError( return SQLITE_ERROR );
assert( pVfs->mxPathname==MAX_PATHNAME );
#if defined(__RTP__) || defined(_WRS_KERNEL)
{
char *zRealname = vxrealpath(zPath, 0);
zOut[0] = '\0';
if( !zRealname ){
return SQLITE_CANTOPEN;
}
sqlite3_snprintf(nOut, zOut, "%s", zRealname);
sqlite3_free(zRealname);
return SQLITE_OK;
}
#else
zOut[nOut-1] = '\0';
if( zPath[0]=='/' ){
sqlite3_snprintf(nOut, zOut, "%s", zPath);
}else{
int nCwd;
if( getcwd(zOut, nOut-1)==0 ){
return SQLITE_CANTOPEN;
}
nCwd = strlen(zOut);
sqlite3_snprintf(nOut-nCwd, &zOut[nCwd], "/%s", zPath);
}
return SQLITE_OK;
#if 0
/*
** Remove "/./" path elements and convert "/A/./" path elements
** to just "/".
*/
if( zFull ){
int i, j;
for(i=j=0; zFull[i]; i++){
if( zFull[i]=='/' ){
if( zFull[i+1]=='/' ) continue;
if( zFull[i+1]=='.' && zFull[i+2]=='/' ){
i += 1;
continue;
}
if( zFull[i+1]=='.' && zFull[i+2]=='.' && zFull[i+3]=='/' ){
while( j>0 && zFull[j-1]!='/' ){ j--; }
i += 3;
continue;
}
}
zFull[j++] = zFull[i];
}
zFull[j] = 0;
}
#endif
#endif
}
#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
#include <dlfcn.h>
static void *unixDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
return dlopen(zFilename, RTLD_NOW | RTLD_GLOBAL);
}
/*
** SQLite calls this function immediately after a call to unixDlSym() or
** unixDlOpen() fails (returns a null pointer). If a more detailed error
** message is available, it is written to zBufOut. If no error message
** is available, zBufOut is left unmodified and SQLite uses a default
** error message.
*/
static void unixDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
char *zErr;
enterMutex();
zErr = dlerror();
if( zErr ){
sqlite3_snprintf(nBuf, zBufOut, "%s", zErr);
}
leaveMutex();
}
static void *unixDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
return dlsym(pHandle, zSymbol);
}
static void unixDlClose(sqlite3_vfs *pVfs, void *pHandle){
dlclose(pHandle);
}
#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
#define unixDlOpen 0
#define unixDlError 0
#define unixDlSym 0
#define unixDlClose 0
#endif
/*
** Write nBuf bytes of random data to the supplied buffer zBuf.
*/
static int unixRandomness(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
assert((size_t)nBuf>=(sizeof(time_t)+sizeof(int)));
/* We have to initialize zBuf to prevent valgrind from reporting
** errors. The reports issued by valgrind are incorrect - we would
** prefer that the randomness be increased by making use of the
** uninitialized space in zBuf - but valgrind errors tend to worry
** some users. Rather than argue, it seems easier just to initialize
** the whole array and silence valgrind, even if that means less randomness
** in the random seed.
**
** When testing, initializing zBuf[] to zero is all we do. That means
** that we always use the same random number sequence. This makes the
** tests repeatable.
*/
memset(zBuf, 0, nBuf);
#if !defined(SQLITE_TEST)
{
int pid, fd;
fd = open("/dev/urandom", O_RDONLY);
if( fd<0 ){
time_t t;
time(&t);
memcpy(zBuf, &t, sizeof(t));
pid = getpid();
memcpy(&zBuf[sizeof(t)], &pid, sizeof(pid));
assert( sizeof(t)+sizeof(pid)<=(size_t)nBuf );
nBuf = sizeof(t) + sizeof(pid);
}else{
nBuf = read(fd, zBuf, nBuf);
close(fd);
}
}
#endif
return nBuf;
}
/*
** Sleep for a little while. Return the amount of time slept.
** The argument is the number of microseconds we want to sleep.
** The return value is the number of microseconds of sleep actually
** requested from the underlying operating system, a number which
** might be greater than or equal to the argument, but not less
** than the argument.
*/
static int unixSleep(sqlite3_vfs *pVfs, int microseconds){
#if defined(__RTP__) || defined(_WRS_KERNEL)
struct timespec sp;
sp.tv_sec = microseconds / 1000000;
sp.tv_nsec = (microseconds % 1000000) * 1000;
nanosleep(&sp, NULL);
#else
#if defined(HAVE_USLEEP) && HAVE_USLEEP
usleep(microseconds);
return microseconds;
#else
int seconds = (microseconds+999999)/1000000;
sleep(seconds);
return seconds*1000000;
#endif
#endif
}
/*
** The following variable, if set to a non-zero value, becomes the result
** returned from sqlite3OsCurrentTime(). This is used for testing.
*/
#ifdef SQLITE_TEST
int sqlite3_current_time = 0;
#endif
/*
** Find the current time (in Universal Coordinated Time). Write the
** current time and date as a Julian Day number into *prNow and
** return 0. Return 1 if the time and date cannot be found.
*/
static int unixCurrentTime(sqlite3_vfs *pVfs, double *prNow){
#if defined(__RTP__) || defined(_WRS_KERNEL)
struct timespec sNow;
clock_gettime(CLOCK_REALTIME, &sNow);
*prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_nsec/86400000000000.0;
#else
#ifdef NO_GETTOD
time_t t;
time(&t);
*prNow = t/86400.0 + 2440587.5;
#else
struct timeval sNow;
gettimeofday(&sNow, 0);
*prNow = 2440587.5 + sNow.tv_sec/86400.0 + sNow.tv_usec/86400000000.0;
#endif
#endif
#ifdef SQLITE_TEST
if( sqlite3_current_time ){
*prNow = sqlite3_current_time/86400.0 + 2440587.5;
}
#endif
return 0;
}
static int unixGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
return 0;
}
/*
** Initialize the operating system interface.
*/
int sqlite3_os_init(void){
/* Macro to define the static contents of an sqlite3_vfs structure for
** the unix backend. The two parameters are the values to use for
** the sqlite3_vfs.zName and sqlite3_vfs.pAppData fields, respectively.
**
*/
#define UNIXVFS(zVfsName, pVfsAppData) { \
1, /* iVersion */ \
sizeof(unixFile), /* szOsFile */ \
MAX_PATHNAME, /* mxPathname */ \
0, /* pNext */ \
zVfsName, /* zName */ \
(void *)pVfsAppData, /* pAppData */ \
unixOpen, /* xOpen */ \
unixDelete, /* xDelete */ \
unixAccess, /* xAccess */ \
unixFullPathname, /* xFullPathname */ \
unixDlOpen, /* xDlOpen */ \
unixDlError, /* xDlError */ \
unixDlSym, /* xDlSym */ \
unixDlClose, /* xDlClose */ \
unixRandomness, /* xRandomness */ \
unixSleep, /* xSleep */ \
unixCurrentTime, /* xCurrentTime */ \
unixGetLastError /* xGetLastError */ \
}
static sqlite3_vfs unixVfs = UNIXVFS("unix", 0);
#if SQLITE_ENABLE_LOCKING_STYLE
int i;
static sqlite3_vfs aVfs[] = {
UNIXVFS("unix-posix", LOCKING_STYLE_POSIX),
UNIXVFS("unix-afp", LOCKING_STYLE_AFP),
UNIXVFS("unix-flock", LOCKING_STYLE_FLOCK),
UNIXVFS("unix-dotfile", LOCKING_STYLE_DOTFILE),
UNIXVFS("unix-none", LOCKING_STYLE_NONE),
UNIXVFS("unix-namedsem",LOCKING_STYLE_NAMEDSEM),
};
for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
sqlite3_vfs_register(&aVfs[i], 0);
}
#endif
#if defined(__RTP__) || defined(_WRS_KERNEL)
sqlite3HashInit(&nameHash, 1);
#endif
sqlite3_vfs_register(&unixVfs, 1);
return SQLITE_OK;
}
/*
** Shutdown the operating system interface. This is a no-op for unix.
*/
int sqlite3_os_end(void){
return SQLITE_OK;
}
#endif /* SQLITE_OS_UNIX */