diff options
Diffstat (limited to 'third_party/sqlite/src/os_unix.c')
| -rwxr-xr-x | third_party/sqlite/src/os_unix.c | 2750 |
1 files changed, 2750 insertions, 0 deletions
diff --git a/third_party/sqlite/src/os_unix.c b/third_party/sqlite/src/os_unix.c new file mode 100755 index 0000000..4874a64 --- /dev/null +++ b/third_party/sqlite/src/os_unix.c @@ -0,0 +1,2750 @@ +/* +** 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 1.195 2008/07/30 17:28:04 drh Exp $ +*/ +#include "sqliteInt.h" +#if SQLITE_OS_UNIX /* This file is used on unix only */ + +/* +** If SQLITE_ENABLE_LOCKING_STYLE is defined, then several different +** locking implementations are provided: +** +** * POSIX locking (the default), +** * No locking, +** * Dot-file locking, +** * flock() locking, +** * AFP locking (OSX only). +*/ +/* #define SQLITE_ENABLE_LOCKING_STYLE 0 */ + +/* +** 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> + +#ifdef SQLITE_ENABLE_LOCKING_STYLE +#include <sys/ioctl.h> +#include <sys/param.h> +#include <sys/mount.h> +#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 */ +#ifdef 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 +}; + +/* +** 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 */ + ino_t ino; /* Inode number */ +#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 */ + ino_t ino; /* Inode number */ +}; + +/* +** 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() */ + 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; + +/* +** 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 +** 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 + +/* +** Helper functions to obtain and relinquish the global mutex. +*/ +static void enterMutex(){ + sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER)); +} +static void leaveMutex(){ + 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 */ + +/* +** The testThreadLockingBehavior() routine launches two separate +** threads on this routine. This routine attempts to lock a file +** descriptor then returns. The success or failure of that attempt +** allows the testThreadLockingBehavior() procedure to determine +** whether or not threads can override each others locks. +*/ +static void *threadLockingTest(void *pArg){ + struct threadTestData *pData = (struct threadTestData*)pArg; + pData->result = fcntl(pData->fd, F_SETLK, &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; + struct threadTestData d[2]; + pthread_t t[2]; + + fd = dup(fd_orig); + if( fd<0 ) return; + memset(d, 0, sizeof(d)); + d[0].fd = fd; + d[0].lock.l_type = F_RDLCK; + d[0].lock.l_len = 1; + d[0].lock.l_start = 0; + d[0].lock.l_whence = SEEK_SET; + d[1] = d[0]; + d[1].lock.l_type = F_WRLCK; + pthread_create(&t[0], 0, threadLockingTest, &d[0]); + pthread_create(&t[1], 0, threadLockingTest, &d[1]); + pthread_join(t[0], 0); + pthread_join(t[1], 0); + close(fd); + threadsOverrideEachOthersLocks = d[0].result==0 && d[1].result==0; +} +#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); + } + } +} + +#ifdef 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. +*/ +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. + */ + return LOCKING_STYLE_DOTFILE; +} +#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 +){ +#ifdef SQLITE_ENABLE_LOCKING_STYLE + struct Mapping { + const char *zFilesystem; + int eLockingStyle; + } aMap[] = { + { "hfs", LOCKING_STYLE_POSIX }, + { "ufs", LOCKING_STYLE_POSIX }, + { "afpfs", LOCKING_STYLE_AFP }, + { "smbfs", LOCKING_STYLE_FLOCK }, + { "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 (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 + 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 */ + 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; + key1.ino = statbuf.st_ino; +#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; + key2.ino = statbuf.st_ino; + 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; + }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); + rc = findLockInfo(pFile->h, &pFile->pLock, 0); + 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{ + 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); + }else{ + rc = fsync(fd); + } +#endif /* HAVE_FULLFSYNC */ +#endif /* defined(SQLITE_NO_SYNC) */ + + 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 + ); + + 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 checks if there is a RESERVED lock held on the specified +** file by this or any other process. If such a lock is held, return +** non-zero. If the file is unlocked or holds only SHARED locks, then +** return zero. +*/ +static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){ + int r = 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 ){ + r = 1; + } + + /* Otherwise see if some other process holds it. + */ + if( !r ){ + struct flock lock; + lock.l_whence = SEEK_SET; + lock.l_start = RESERVED_BYTE; + lock.l_len = 1; + lock.l_type = F_WRLCK; + fcntl(pFile->h, F_GETLK, &lock); + if( lock.l_type!=F_UNLCK ){ + r = 1; + } + } + + leaveMutex(); + OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r); + + *pResOut = r; + return SQLITE_OK; +} + +/* +** 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) ){ + rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; + 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 ){ + assert( pLock->cnt==0 ); + assert( pLock->locktype==0 ); + + /* Now get the read-lock */ + lock.l_start = SHARED_FIRST; + lock.l_len = SHARED_SIZE; + s = fcntl(pFile->h, F_SETLK, &lock); + + /* 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 ){ + rc = SQLITE_IOERR_UNLOCK; /* This should never happen */ + goto end_lock; + } + if( s==(-1) ){ + rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; + }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) ){ + rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; + } + } + + 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) ){ + rc = SQLITE_IOERR_RDLOCK; + } + } + 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{ + rc = SQLITE_IOERR_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{ + rc = SQLITE_IOERR_UNLOCK; + pLock->cnt = 1; + } + } + + /* 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; + } + } + } + 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); + } + 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; +} + + +#ifdef SQLITE_ENABLE_LOCKING_STYLE +#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 0 on success, 1 on failure. To match the behavior of the +** normal posix file locking (used in unixLock for example), we should +** provide 'richer' return codes - specifically to differentiate between +** 'file busy' and 'file system error' results. +*/ +static int _AFPFSSetLock( + const char *path, + int fd, + 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 = fd; + OSTRACE5("AFPLOCK setting lock %s for %d in range %llx:%llx\n", + (setLockFlag?"ON":"OFF"), fd, offset, length); + err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0); + if ( err==-1 ) { + OSTRACE4("AFPLOCK failed to fsctl() '%s' %d %s\n", path, errno, + strerror(errno)); + return 1; /* error */ + } else { + return 0; + } +} + +/* + ** 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, return + ** non-zero. If the file is unlocked or holds only SHARED locks, then + ** return zero. + */ +static int afpCheckReservedLock(sqlite3_file *id, int *pResOut){ + int r = 0; + unixFile *pFile = (unixFile*)id; + + assert( pFile ); + afpLockingContext *context = (afpLockingContext *) pFile->lockingContext; + + /* Check if a thread in this process holds such a lock */ + if( pFile->locktype>SHARED_LOCK ){ + r = 1; + } + + /* Otherwise see if some other process holds it. + */ + if ( !r ) { + /* lock the byte */ + int failed = _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1,1); + if (failed) { + /* if we failed to get the lock then someone else must have it */ + r = 1; + } else { + /* if we succeeded in taking the reserved lock, unlock it to restore + ** the original state */ + _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0); + } + } + OSTRACE3("TEST WR-LOCK %d %d\n", pFile->h, r); + + *pResOut = r; + return SQLITE_OK; +} + +/* 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->h, PENDING_BYTE, 1, 1); + if (failed) { + rc = SQLITE_BUSY; + 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, failed; + + /* Now get the read-lock */ + /* note that the quality of the randomness doesn't matter that much */ + lk = random(); + context->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1); + failed = _AFPFSSetLock(context->filePath, pFile->h, + SHARED_FIRST+context->sharedLockByte, 1, 1); + + /* Drop the temporary PENDING lock */ + if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)) { + rc = SQLITE_IOERR_UNLOCK; /* This should never happen */ + goto afp_end_lock; + } + + if( failed ){ + rc = SQLITE_BUSY; + } 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->h, 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 (!_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST + + context->sharedLockByte, 1, 0)) { + /* now attemmpt to get the exclusive lock range */ + failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST, + SHARED_SIZE, 1); + if (failed && _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST + + context->sharedLockByte, 1, 1)) { + rc = SQLITE_IOERR_RDLOCK; /* this should never happen */ + } + } else { + /* */ + rc = SQLITE_IOERR_UNLOCK; /* this should never happen */ + } + } + if( failed && rc == SQLITE_OK){ + rc = SQLITE_BUSY; + } + } + + 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(); + if( pFile->locktype>SHARED_LOCK ){ + if( locktype==SHARED_LOCK ){ + int failed = 0; + + /* unlock the exclusive range - then re-establish the shared lock */ + if (pFile->locktype==EXCLUSIVE_LOCK) { + failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST, + SHARED_SIZE, 0); + if (!failed) { + /* successfully removed the exclusive lock */ + if (_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST+ + context->sharedLockByte, 1, 1)) { + /* failed to re-establish our shared lock */ + rc = SQLITE_IOERR_RDLOCK; /* This should never happen */ + } + } else { + /* This should never happen - failed to unlock the exclusive range */ + rc = SQLITE_IOERR_UNLOCK; + } + } + } + if (rc == SQLITE_OK && pFile->locktype>=PENDING_LOCK) { + if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)){ + /* failed to release the pending lock */ + rc = SQLITE_IOERR_UNLOCK; /* This should never happen */ + } + } + if (rc == SQLITE_OK && pFile->locktype>=RESERVED_LOCK) { + if (_AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0)) { + /* failed to release the reserved lock */ + rc = SQLITE_IOERR_UNLOCK; /* This should never happen */ + } + } + } + if( locktype==NO_LOCK ){ + int failed = _AFPFSSetLock(context->filePath, pFile->h, + SHARED_FIRST + context->sharedLockByte, 1, 0); + if (failed) { + rc = SQLITE_IOERR_UNLOCK; /* This should never happen */ + } + } + 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; + +static int flockCheckReservedLock(sqlite3_file *id, int *pResOut){ + int r = 1; + unixFile *pFile = (unixFile*)id; + + if (pFile->locktype != RESERVED_LOCK) { + /* attempt to get the lock */ + int rc = flock(pFile->h, LOCK_EX | LOCK_NB); + if (!rc) { + /* got the lock, unlock it */ + flock(pFile->h, LOCK_UN); + r = 0; /* no one has it reserved */ + } + } + + *pResOut = r; + return SQLITE_OK; +} + +static int flockLock(sqlite3_file *id, int locktype) { + unixFile *pFile = (unixFile*)id; + + /* 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 */ + int rc = flock(pFile->h, LOCK_EX | LOCK_NB); + if (rc) { + /* didn't get, must be busy */ + return SQLITE_BUSY; + } else { + /* got it, set the type and return ok */ + pFile->locktype = locktype; + return SQLITE_OK; + } +} + +static int flockUnlock(sqlite3_file *id, int locktype) { + unixFile *pFile = (unixFile*)id; + + 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) + return SQLITE_IOERR_UNLOCK; + 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); +} + +#pragma mark Old-School .lock file based locking + +static int dotlockCheckReservedLock(sqlite3_file *id, int *pResOut) { + int r = 1; + unixFile *pFile = (unixFile*)id; + char *zLockFile = (char *)pFile->lockingContext; + + if (pFile->locktype != RESERVED_LOCK) { + struct stat statBuf; + if (lstat(zLockFile, &statBuf) != 0){ + /* file does not exist, we could have it if we want it */ + r = 0; + } + } + + *pResOut = r; + return SQLITE_OK; +} + +static int dotlockLock(sqlite3_file *id, int locktype) { + unixFile *pFile = (unixFile*)id; + int fd; + char *zLockFile = (char *)pFile->lockingContext; + + /* 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; + + /* Always update the timestamp on the old file */ + utimes(zLockFile, NULL); + return SQLITE_OK; + } + + /* check to see if lock file already exists */ + struct stat statBuf; + if (lstat(zLockFile,&statBuf) == 0){ + return SQLITE_BUSY; /* it does, busy */ + } + + /* 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 */ + return SQLITE_BUSY; + } + close(fd); + + /* got it, set the type and return ok */ + pFile->locktype = locktype; + return SQLITE_OK; +} + +static int dotlockUnlock(sqlite3_file *id, int locktype) { + unixFile *pFile = (unixFile*)id; + char *zLockFile = (char *)pFile->lockingContext; + + 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. */ + unlink(zLockFile); + pFile->locktype = NO_LOCK; + return SQLITE_OK; +} + +/* + ** Close a file. + */ +static int dotlockClose(sqlite3_file *id) { + if( id ){ + unixFile *pFile = (unixFile*)id; + dotlockUnlock(id, NO_LOCK); + sqlite3_free(pFile->lockingContext); + } + return closeUnixFile(id); +} + + +#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) { + return closeUnixFile(id); +} + + +/* +** 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 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) +#ifdef SQLITE_ENABLE_LOCKING_STYLE + ,IOMETHODS(dotlockClose, dotlockLock, dotlockUnlock,dotlockCheckReservedLock) + ,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock) + ,IOMETHODS(afpClose, afpLock, afpUnlock, afpCheckReservedLock) +#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( pNew->pLock==NULL ); + assert( pNew->pOpen==NULL ); + + OSTRACE3("OPEN %-3d %s\n", h, zFilename); + pNew->h = h; + pNew->dirfd = dirfd; + SET_THREADID(pNew); + + if( noLock ){ + eLockingStyle = LOCKING_STYLE_NONE; + }else{ + eLockingStyle = detectLockingStyle(pVfs, zFilename, h); + } + + switch( eLockingStyle ){ + + case LOCKING_STYLE_POSIX: { + enterMutex(); + rc = findLockInfo(h, &pNew->pLock, &pNew->pOpen); + leaveMutex(); + break; + } + +#ifdef SQLITE_ENABLE_LOCKING_STYLE + 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; + } + + 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; + } + + case LOCKING_STYLE_FLOCK: + case LOCKING_STYLE_NONE: + break; +#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<sizeof(azDirs)/sizeof(azDirs[0]); 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) >= 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); + 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 ){ + unlink(zName); + } + 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); +} + +/* +** 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); + if( dirSync ){ + int fd; + rc = openDirectory(zPath, &fd); + if( rc==SQLITE_OK ){ + if( fsync(fd) ){ + rc = SQLITE_IOERR_DIR_FSYNC; + } + close(fd); + } + } + 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 ); + 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 +} + + +#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(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)); + }else{ + read(fd, zBuf, nBuf); + close(fd); + } + } +#endif + return SQLITE_OK; +} + + +/* +** 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(HAVE_USLEEP) && HAVE_USLEEP + usleep(microseconds); + return microseconds; +#else + int seconds = (microseconds+999999)/1000000; + sleep(seconds); + return seconds*1000000; +#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){ +#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 +#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); +#ifdef SQLITE_ENABLE_LOCKING_STYLE +#if 0 + 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) + }; + for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){ + sqlite3_vfs_register(&aVfs[i], 0); + } +#endif +#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 */ |