diff options
Diffstat (limited to 'ext/pdo_sqlite/sqlite/src/os_unix.c')
| -rw-r--r-- | ext/pdo_sqlite/sqlite/src/os_unix.c | 1992 |
1 files changed, 0 insertions, 1992 deletions
diff --git a/ext/pdo_sqlite/sqlite/src/os_unix.c b/ext/pdo_sqlite/sqlite/src/os_unix.c deleted file mode 100644 index 5b58cb7aac..0000000000 --- a/ext/pdo_sqlite/sqlite/src/os_unix.c +++ /dev/null @@ -1,1992 +0,0 @@ -/* -** 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. -*/ -#include "sqliteInt.h" -#include "os.h" -#if OS_UNIX /* This file is used on unix only */ - -/* -** 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 we are to be thread-safe, include the pthreads header and define -** the SQLITE_UNIX_THREADS macro. -*/ -#if defined(THREADSAFE) && 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 - - - -/* -** The unixFile structure is subclass of OsFile specific for the unix -** protability layer. -*/ -typedef struct unixFile unixFile; -struct unixFile { - IoMethod const *pMethod; /* Always the first entry */ - struct openCnt *pOpen; /* Info about all open fd's on this inode */ - struct lockInfo *pLock; /* Info about locks on this inode */ - int h; /* The file descriptor */ - unsigned char locktype; /* The type of lock held on this fd */ - unsigned char isOpen; /* True if needs to be closed */ - unsigned char fullSync; /* Use F_FULLSYNC if available */ - int dirfd; /* File descriptor for the directory */ - i64 offset; /* Seek offset */ -#ifdef SQLITE_UNIX_THREADS - pthread_t tid; /* The thread that "owns" this OsFile */ -#endif -}; - -/* -** Provide the ability to override some OS-layer functions during -** testing. This is used to simulate OS crashes to verify that -** commits are atomic even in the event of an OS crash. -*/ -#ifdef SQLITE_CRASH_TEST - extern int sqlite3CrashTestEnable; - extern int sqlite3CrashOpenReadWrite(const char*, OsFile**, int*); - extern int sqlite3CrashOpenExclusive(const char*, OsFile**, int); - extern int sqlite3CrashOpenReadOnly(const char*, OsFile**, int); -# define CRASH_TEST_OVERRIDE(X,A,B,C) \ - if(sqlite3CrashTestEnable){ return X(A,B,C); } -#else -# define CRASH_TEST_OVERRIDE(X,A,B,C) /* no-op */ -#endif - - -/* -** Include code that is common to all os_*.c files -*/ -#include "os_common.h" - -/* -** Do not include any of the File I/O interface procedures if the -** SQLITE_OMIT_DISKIO macro is defined (indicating that the database -** will be in-memory only) -*/ -#ifndef SQLITE_OMIT_DISKIO - - -/* -** 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's 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. -*/ -#ifdef SQLITE_UNIX_THREADS -#define threadid pthread_self() -#else -#define threadid 0 -#endif - -/* -** Set or check the OsFile.tid field. This field is set when an OsFile -** is first opened. All subsequent uses of the OsFile verify that the -** same thread is operating on the OsFile. 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): OsFiles 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 OsFile.pLock field needs to be -** recomputed because its key includes the thread-id. See the -** transferOwnership() function below for additional information -*/ -#if defined(SQLITE_UNIX_THREADS) -# 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 fd1 = open("./file1", O_RDWR|O_CREAT, 0644); -** 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 OsFile 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 OsFile 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 OsFile structure contains -** a pointer to an openCnt structure. There is one openCnt structure -** per open inode, which means that multiple OsFiles can point to a single -** openCnt. When an attempt is made to close an OsFile, if there are -** other OsFiles 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 */ -#ifdef SQLITE_UNIX_THREADS - 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 OsFile -** structure contains a pointer to an instance of this object and this -** object keeps a count of the number of OsFiles 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 */ -}; - -/* -** 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() */ -}; - -/* -** These hash tables map inodes and file descriptors (really, lockKey and -** openKey structures) into lockInfo and openCnt structures. Access to -** these hash tables must be protected by a mutex. -*/ -static Hash lockHash = {SQLITE_HASH_BINARY, 0, 0, 0, - sqlite3ThreadSafeMalloc, sqlite3ThreadSafeFree, 0, 0}; -static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0, - sqlite3ThreadSafeMalloc, sqlite3ThreadSafeFree, 0, 0}; - -#ifdef SQLITE_UNIX_THREADS -/* -** 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 && 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_UNIX_THREADS */ - -/* -** Release a lockInfo structure previously allocated by findLockInfo(). -*/ -static void releaseLockInfo(struct lockInfo *pLock){ - assert( sqlite3OsInMutex(1) ); - pLock->nRef--; - if( pLock->nRef==0 ){ - sqlite3HashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0); - sqlite3ThreadSafeFree(pLock); - } -} - -/* -** Release a openCnt structure previously allocated by findLockInfo(). -*/ -static void releaseOpenCnt(struct openCnt *pOpen){ - assert( sqlite3OsInMutex(1) ); - pOpen->nRef--; - if( pOpen->nRef==0 ){ - sqlite3HashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0); - free(pOpen->aPending); - sqlite3ThreadSafeFree(pOpen); - } -} - -/* -** 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 the number of errors. -*/ -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 ) return 1; - - assert( sqlite3OsInMutex(1) ); - memset(&key1, 0, sizeof(key1)); - key1.dev = statbuf.st_dev; - key1.ino = statbuf.st_ino; -#ifdef SQLITE_UNIX_THREADS - 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 = (struct lockInfo*)sqlite3HashFind(&lockHash, &key1, sizeof(key1)); - if( pLock==0 ){ - struct lockInfo *pOld; - pLock = sqlite3ThreadSafeMalloc( sizeof(*pLock) ); - if( pLock==0 ){ - rc = 1; - goto exit_findlockinfo; - } - pLock->key = key1; - pLock->nRef = 1; - pLock->cnt = 0; - pLock->locktype = 0; - pOld = sqlite3HashInsert(&lockHash, &pLock->key, sizeof(key1), pLock); - if( pOld!=0 ){ - assert( pOld==pLock ); - sqlite3ThreadSafeFree(pLock); - rc = 1; - goto exit_findlockinfo; - } - }else{ - pLock->nRef++; - } - *ppLock = pLock; - if( ppOpen!=0 ){ - pOpen = (struct openCnt*)sqlite3HashFind(&openHash, &key2, sizeof(key2)); - if( pOpen==0 ){ - struct openCnt *pOld; - pOpen = sqlite3ThreadSafeMalloc( sizeof(*pOpen) ); - if( pOpen==0 ){ - releaseLockInfo(pLock); - rc = 1; - goto exit_findlockinfo; - } - pOpen->key = key2; - pOpen->nRef = 1; - pOpen->nLock = 0; - pOpen->nPending = 0; - pOpen->aPending = 0; - pOld = sqlite3HashInsert(&openHash, &pOpen->key, sizeof(key2), pOpen); - if( pOld!=0 ){ - assert( pOld==pOpen ); - sqlite3ThreadSafeFree(pOpen); - releaseLockInfo(pLock); - rc = 1; - goto exit_findlockinfo; - } - }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. -*/ -#ifdef SQLITE_UNIX_THREADS -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 */ - TRACE1("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; - } - TRACE4("Transfer ownership of %d from %d to %d\n", pFile->h,pFile->tid,hSelf); - pFile->tid = hSelf; - releaseLockInfo(pFile->pLock); - rc = findLockInfo(pFile->h, &pFile->pLock, 0); - TRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h, - locktypeName(pFile->locktype), - locktypeName(pFile->pLock->locktype), pFile->pLock->cnt); - return rc; -} -#else - /* On single-threaded builds, ownership transfer is a no-op */ -# define transferOwnership(X) SQLITE_OK -#endif - -/* -** Delete the named file -*/ -int sqlite3UnixDelete(const char *zFilename){ - unlink(zFilename); - return SQLITE_OK; -} - -/* -** Return TRUE if the named file exists. -*/ -int sqlite3UnixFileExists(const char *zFilename){ - return access(zFilename, 0)==0; -} - -/* Forward declaration */ -static int allocateUnixFile(unixFile *pInit, OsFile **pId); - -/* -** Attempt to open a file for both reading and writing. If that -** fails, try opening it read-only. If the file does not exist, -** try to create it. -** -** On success, a handle for the open file is written to *id -** and *pReadonly is set to 0 if the file was opened for reading and -** writing or 1 if the file was opened read-only. The function returns -** SQLITE_OK. -** -** On failure, the function returns SQLITE_CANTOPEN and leaves -** *id and *pReadonly unchanged. -*/ -int sqlite3UnixOpenReadWrite( - const char *zFilename, - OsFile **pId, - int *pReadonly -){ - int rc; - unixFile f; - - CRASH_TEST_OVERRIDE(sqlite3CrashOpenReadWrite, zFilename, pId, pReadonly); - assert( 0==*pId ); - f.h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY, - SQLITE_DEFAULT_FILE_PERMISSIONS); - if( f.h<0 ){ -#ifdef EISDIR - if( errno==EISDIR ){ - return SQLITE_CANTOPEN; - } -#endif - f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY); - if( f.h<0 ){ - return SQLITE_CANTOPEN; - } - *pReadonly = 1; - }else{ - *pReadonly = 0; - } - sqlite3OsEnterMutex(); - rc = findLockInfo(f.h, &f.pLock, &f.pOpen); - sqlite3OsLeaveMutex(); - if( rc ){ - close(f.h); - return SQLITE_NOMEM; - } - TRACE3("OPEN %-3d %s\n", f.h, zFilename); - return allocateUnixFile(&f, pId); -} - - -/* -** Attempt to open a new file for exclusive access by this process. -** The file will be opened for both reading and writing. To avoid -** a potential security problem, we do not allow the file to have -** previously existed. Nor do we allow the file to be a symbolic -** link. -** -** If delFlag is true, then make arrangements to automatically delete -** the file when it is closed. -** -** On success, write the file handle into *id and return SQLITE_OK. -** -** On failure, return SQLITE_CANTOPEN. -*/ -int sqlite3UnixOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){ - int rc; - unixFile f; - - CRASH_TEST_OVERRIDE(sqlite3CrashOpenExclusive, zFilename, pId, delFlag); - assert( 0==*pId ); - f.h = open(zFilename, - O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY, - SQLITE_DEFAULT_FILE_PERMISSIONS); - if( f.h<0 ){ - return SQLITE_CANTOPEN; - } - sqlite3OsEnterMutex(); - rc = findLockInfo(f.h, &f.pLock, &f.pOpen); - sqlite3OsLeaveMutex(); - if( rc ){ - close(f.h); - unlink(zFilename); - return SQLITE_NOMEM; - } - if( delFlag ){ - unlink(zFilename); - } - TRACE3("OPEN-EX %-3d %s\n", f.h, zFilename); - return allocateUnixFile(&f, pId); -} - -/* -** Attempt to open a new file for read-only access. -** -** On success, write the file handle into *id and return SQLITE_OK. -** -** On failure, return SQLITE_CANTOPEN. -*/ -int sqlite3UnixOpenReadOnly(const char *zFilename, OsFile **pId){ - int rc; - unixFile f; - - CRASH_TEST_OVERRIDE(sqlite3CrashOpenReadOnly, zFilename, pId, 0); - assert( 0==*pId ); - f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY); - if( f.h<0 ){ - return SQLITE_CANTOPEN; - } - sqlite3OsEnterMutex(); - rc = findLockInfo(f.h, &f.pLock, &f.pOpen); - sqlite3OsLeaveMutex(); - if( rc ){ - close(f.h); - return SQLITE_NOMEM; - } - TRACE3("OPEN-RO %-3d %s\n", f.h, zFilename); - return allocateUnixFile(&f, pId); -} - -/* -** Attempt to open a file descriptor for the directory that contains a -** file. This file descriptor can be used to fsync() the directory -** in order to make sure the creation of a new file is actually written -** to disk. -** -** This routine is only meaningful for Unix. It is a no-op under -** windows since windows does not support hard links. -** -** On success, a handle for a previously open file at *id is -** updated with the new directory file descriptor and SQLITE_OK is -** returned. -** -** On failure, the function returns SQLITE_CANTOPEN and leaves -** *id unchanged. -*/ -static int unixOpenDirectory( - OsFile *id, - const char *zDirname -){ - unixFile *pFile = (unixFile*)id; - if( pFile==0 ){ - /* Do not open the directory if the corresponding file is not already - ** open. */ - return SQLITE_CANTOPEN; - } - SET_THREADID(pFile); - assert( pFile->dirfd<0 ); - pFile->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0); - if( pFile->dirfd<0 ){ - return SQLITE_CANTOPEN; - } - TRACE3("OPENDIR %-3d %s\n", pFile->dirfd, zDirname); - return SQLITE_OK; -} - -/* -** If the following global variable points to a string which is the -** name of a directory, then that directory will be used to store -** temporary files. -** -** See also the "PRAGMA temp_store_directory" SQL command. -*/ -char *sqlite3_temp_directory = 0; - -/* -** Create a temporary file name in zBuf. zBuf must be big enough to -** hold at least SQLITE_TEMPNAME_SIZE characters. -*/ -int sqlite3UnixTempFileName(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 = "."; - 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; - } - do{ - sprintf(zBuf, "%s/"TEMP_FILE_PREFIX, zDir); - j = strlen(zBuf); - sqlite3Randomness(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; -} - -/* -** Check that a given pathname is a directory and is writable -** -*/ -int sqlite3UnixIsDirWritable(char *zBuf){ -#ifndef SQLITE_OMIT_PAGER_PRAGMAS - struct stat buf; - if( zBuf==0 ) return 0; - if( zBuf[0]==0 ) return 0; - if( stat(zBuf, &buf) ) return 0; - if( !S_ISDIR(buf.st_mode) ) return 0; - if( access(zBuf, 07) ) return 0; -#endif /* SQLITE_OMIT_PAGER_PRAGMAS */ - return 1; -} - -/* -** 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 seekAndRead(unixFile *id, void *pBuf, int cnt){ - int got; -#ifdef USE_PREAD - got = pread(id->h, pBuf, cnt, id->offset); -#else - lseek(id->h, id->offset, SEEK_SET); - got = read(id->h, pBuf, cnt); -#endif - if( got>0 ){ - id->offset += got; - } - 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(OsFile *id, void *pBuf, int amt){ - int got; - assert( id ); - SimulateIOError(SQLITE_IOERR); - TIMER_START; - got = seekAndRead((unixFile*)id, pBuf, amt); - TIMER_END; - TRACE5("READ %-3d %5d %7d %d\n", ((unixFile*)id)->h, got, - last_page, TIMER_ELAPSED); - SEEK(0); - /* if( got<0 ) got = 0; */ - if( got==amt ){ - return SQLITE_OK; - }else{ - return SQLITE_IOERR; - } -} - -/* -** 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, const void *pBuf, int cnt){ - int got; -#ifdef USE_PREAD - got = pwrite(id->h, pBuf, cnt, id->offset); -#else - lseek(id->h, id->offset, SEEK_SET); - got = write(id->h, pBuf, cnt); -#endif - if( got>0 ){ - id->offset += got; - } - 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(OsFile *id, const void *pBuf, int amt){ - int wrote = 0; - assert( id ); - assert( amt>0 ); - SimulateIOError(SQLITE_IOERR); - SimulateDiskfullError; - TIMER_START; - while( amt>0 && (wrote = seekAndWrite((unixFile*)id, pBuf, amt))>0 ){ - amt -= wrote; - pBuf = &((char*)pBuf)[wrote]; - } - TIMER_END; - TRACE5("WRITE %-3d %5d %7d %d\n", ((unixFile*)id)->h, wrote, - last_page, TIMER_ELAPSED); - SEEK(0); - if( amt>0 ){ - return SQLITE_FULL; - } - return SQLITE_OK; -} - -/* -** Move the read/write pointer in a file. -*/ -static int unixSeek(OsFile *id, i64 offset){ - assert( id ); - SEEK(offset/1024 + 1); -#ifdef SQLITE_TEST - if( offset ) SimulateDiskfullError -#endif - ((unixFile*)id)->offset = offset; - 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 FULLSYNC failed, try to do a normal fsync() */ - if( rc ) rc = fsync(fd); - -#else /* if !defined(F_FULLSYNC) */ - if( dataOnly ){ - rc = fdatasync(fd); - }else{ - rc = fsync(fd); - } -#endif /* defined(F_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(OsFile *id, int dataOnly){ - unixFile *pFile = (unixFile*)id; - assert( pFile ); - SimulateIOError(SQLITE_IOERR); - TRACE2("SYNC %-3d\n", pFile->h); - if( full_fsync(pFile->h, pFile->fullSync, dataOnly) ){ - return SQLITE_IOERR; - } - if( pFile->dirfd>=0 ){ - TRACE4("DIRSYNC %-3d (have_fullfsync=%d fullsync=%d)\n", pFile->dirfd, - HAVE_FULLFSYNC, pFile->fullSync); -#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 || !pFile->fullSync) && 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; -} - -/* -** Sync the directory zDirname. This is a no-op on operating systems other -** than UNIX. -** -** This is used to make sure the master journal file has truely been deleted -** before making changes to individual journals on a multi-database commit. -** The F_FULLFSYNC option is not needed here. -*/ -int sqlite3UnixSyncDirectory(const char *zDirname){ -#ifdef SQLITE_DISABLE_DIRSYNC - return SQLITE_OK; -#else - int fd; - int r; - SimulateIOError(SQLITE_IOERR); - fd = open(zDirname, O_RDONLY|O_BINARY, 0); - TRACE3("DIRSYNC %-3d (%s)\n", fd, zDirname); - if( fd<0 ){ - return SQLITE_CANTOPEN; - } - r = fsync(fd); - close(fd); - return ((r==0)?SQLITE_OK:SQLITE_IOERR); -#endif -} - -/* -** Truncate an open file to a specified size -*/ -static int unixTruncate(OsFile *id, i64 nByte){ - assert( id ); - SimulateIOError(SQLITE_IOERR); - return ftruncate(((unixFile*)id)->h, nByte)==0 ? SQLITE_OK : SQLITE_IOERR; -} - -/* -** Determine the current size of a file in bytes -*/ -static int unixFileSize(OsFile *id, i64 *pSize){ - struct stat buf; - assert( id ); - SimulateIOError(SQLITE_IOERR); - if( fstat(((unixFile*)id)->h, &buf)!=0 ){ - return SQLITE_IOERR; - } - *pSize = buf.st_size; - 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(OsFile *id){ - int r = 0; - unixFile *pFile = (unixFile*)id; - - assert( pFile ); - sqlite3OsEnterMutex(); /* 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; - } - } - - sqlite3OsLeaveMutex(); - TRACE3("TEST WR-LOCK %d %d\n", pFile->h, r); - - return r; -} - -/* -** 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(OsFile *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 ); - TRACE7("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 - ** OsFile, do nothing. Don't use the end_lock: exit path, as - ** sqlite3OsEnterMutex() hasn't been called yet. - */ - if( pFile->locktype>=locktype ){ - TRACE3("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 - */ - sqlite3OsEnterMutex(); - - /* Make sure the current thread owns the pFile. - */ - rc = transferOwnership(pFile); - if( rc!=SQLITE_OK ){ - sqlite3OsLeaveMutex(); - return rc; - } - pLock = pFile->pLock; - - /* If some thread using this PID has a lock via a different OsFile* - ** 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 ){ - 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; /* This should never happen */ - goto end_lock; - } - if( s ){ - 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 ){ - 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: - sqlite3OsLeaveMutex(); - TRACE4("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(OsFile *id, int locktype){ - struct lockInfo *pLock; - struct flock lock; - int rc = SQLITE_OK; - unixFile *pFile = (unixFile*)id; - - assert( pFile ); - TRACE7("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; - } - sqlite3OsEnterMutex(); - pLock = pFile->pLock; - assert( pLock->cnt!=0 ); - if( pFile->locktype>SHARED_LOCK ){ - assert( pLock->locktype==pFile->locktype ); - 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(pFile->h, F_SETLK, &lock)!=0 ){ - /* This should never happen */ - rc = SQLITE_IOERR; - } - } - 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(pFile->h, F_SETLK, &lock)==0 ){ - pLock->locktype = SHARED_LOCK; - }else{ - rc = SQLITE_IOERR; /* This should never happen */ - } - } - 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; - if( fcntl(pFile->h, F_SETLK, &lock)==0 ){ - pLock->locktype = NO_LOCK; - }else{ - rc = SQLITE_IOERR; /* This should never happen */ - } - } - - /* 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. - */ - 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]); - } - free(pOpen->aPending); - pOpen->nPending = 0; - pOpen->aPending = 0; - } - } - sqlite3OsLeaveMutex(); - pFile->locktype = locktype; - return rc; -} - -/* -** Close a file. -*/ -static int unixClose(OsFile **pId){ - unixFile *id = (unixFile*)*pId; - - if( !id ) return SQLITE_OK; - unixUnlock(*pId, NO_LOCK); - if( id->dirfd>=0 ) close(id->dirfd); - id->dirfd = -1; - sqlite3OsEnterMutex(); - - if( id->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 = id->pOpen; - aNew = 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] = id->h; - pOpen->nPending++; - } - }else{ - /* There are no outstanding locks so we can close the file immediately */ - close(id->h); - } - releaseLockInfo(id->pLock); - releaseOpenCnt(id->pOpen); - - sqlite3OsLeaveMutex(); - id->isOpen = 0; - TRACE2("CLOSE %-3d\n", id->h); - OpenCounter(-1); - sqlite3ThreadSafeFree(id); - *pId = 0; - return SQLITE_OK; -} - -/* -** Turn a relative pathname into a full pathname. Return a pointer -** to the full pathname stored in space obtained from sqliteMalloc(). -** The calling function is responsible for freeing this space once it -** is no longer needed. -*/ -char *sqlite3UnixFullPathname(const char *zRelative){ - char *zFull = 0; - if( zRelative[0]=='/' ){ - sqlite3SetString(&zFull, zRelative, (char*)0); - }else{ - char *zBuf = sqliteMalloc(5000); - if( zBuf==0 ){ - return 0; - } - zBuf[0] = 0; - sqlite3SetString(&zFull, getcwd(zBuf, 5000), "/", zRelative, - (char*)0); - sqliteFree(zBuf); - } - -#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 - - return zFull; -} - -/* -** Change the value of the fullsync flag in the given file descriptor. -*/ -static void unixSetFullSync(OsFile *id, int v){ - ((unixFile*)id)->fullSync = v; -} - -/* -** Return the underlying file handle for an OsFile -*/ -static int unixFileHandle(OsFile *id){ - return ((unixFile*)id)->h; -} - -/* -** Return an integer that indices the type of lock currently held -** by this handle. (Used for testing and analysis only.) -*/ -static int unixLockState(OsFile *id){ - return ((unixFile*)id)->locktype; -} - -/* -** This vector defines all the methods that can operate on an OsFile -** for unix. -*/ -static const IoMethod sqlite3UnixIoMethod = { - unixClose, - unixOpenDirectory, - unixRead, - unixWrite, - unixSeek, - unixTruncate, - unixSync, - unixSetFullSync, - unixFileHandle, - unixFileSize, - unixLock, - unixUnlock, - unixLockState, - unixCheckReservedLock, -}; - -/* -** Allocate memory for a unixFile. Initialize the new unixFile -** to the value given in pInit and return a pointer to the new -** OsFile. If we run out of memory, close the file and return NULL. -*/ -static int allocateUnixFile(unixFile *pInit, OsFile **pId){ - unixFile *pNew; - pInit->dirfd = -1; - pInit->fullSync = 0; - pInit->locktype = 0; - pInit->offset = 0; - SET_THREADID(pInit); - pNew = sqlite3ThreadSafeMalloc( sizeof(unixFile) ); - if( pNew==0 ){ - close(pInit->h); - sqlite3OsEnterMutex(); - releaseLockInfo(pInit->pLock); - releaseOpenCnt(pInit->pOpen); - sqlite3OsLeaveMutex(); - *pId = 0; - return SQLITE_NOMEM; - }else{ - *pNew = *pInit; - pNew->pMethod = &sqlite3UnixIoMethod; - *pId = (OsFile*)pNew; - OpenCounter(+1); - return SQLITE_OK; - } -} - - -#endif /* SQLITE_OMIT_DISKIO */ -/*************************************************************************** -** Everything above deals with file I/O. Everything that follows deals -** with other miscellanous aspects of the operating system interface -****************************************************************************/ - - -/* -** Get information to seed the random number generator. The seed -** is written into the buffer zBuf[256]. The calling function must -** supply a sufficiently large buffer. -*/ -int sqlite3UnixRandomSeed(char *zBuf){ - /* 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, 256); -#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(time_t)], &pid, sizeof(pid)); - }else{ - read(fd, zBuf, 256); - close(fd); - } - } -#endif - return SQLITE_OK; -} - -/* -** Sleep for a little while. Return the amount of time slept. -** The argument is the number of milliseconds we want to sleep. -*/ -int sqlite3UnixSleep(int ms){ -#if defined(HAVE_USLEEP) && HAVE_USLEEP - usleep(ms*1000); - return ms; -#else - sleep((ms+999)/1000); - return 1000*((ms+999)/1000); -#endif -} - -/* -** Static variables used for thread synchronization. -** -** inMutex the nesting depth of the recursive mutex. The thread -** holding mutexMain can read this variable at any time. -** But is must hold mutexAux to change this variable. Other -** threads must hold mutexAux to read the variable and can -** never write. -** -** mutexOwner The thread id of the thread holding mutexMain. Same -** access rules as for inMutex. -** -** mutexOwnerValid True if the value in mutexOwner is valid. The same -** access rules apply as for inMutex. -** -** mutexMain The main mutex. Hold this mutex in order to get exclusive -** access to SQLite data structures. -** -** mutexAux An auxiliary mutex needed to access variables defined above. -** -** Mutexes are always acquired in this order: mutexMain mutexAux. It -** is not necessary to acquire mutexMain in order to get mutexAux - just -** do not attempt to acquire them in the reverse order: mutexAux mutexMain. -** Either get the mutexes with mutexMain first or get mutexAux only. -** -** When running on a platform where the three variables inMutex, mutexOwner, -** and mutexOwnerValid can be set atomically, the mutexAux is not required. -** On many systems, all three are 32-bit integers and writing to a 32-bit -** integer is atomic. I think. But there are no guarantees. So it seems -** safer to protect them using mutexAux. -*/ -static int inMutex = 0; -#ifdef SQLITE_UNIX_THREADS -static pthread_t mutexOwner; /* Thread holding mutexMain */ -static int mutexOwnerValid = 0; /* True if mutexOwner is valid */ -static pthread_mutex_t mutexMain = PTHREAD_MUTEX_INITIALIZER; /* The mutex */ -static pthread_mutex_t mutexAux = PTHREAD_MUTEX_INITIALIZER; /* Aux mutex */ -#endif - -/* -** The following pair of routine implement mutual exclusion for -** multi-threaded processes. Only a single thread is allowed to -** executed code that is surrounded by EnterMutex() and LeaveMutex(). -** -** SQLite uses only a single Mutex. There is not much critical -** code and what little there is executes quickly and without blocking. -** -** As of version 3.3.2, this mutex must be recursive. -*/ -void sqlite3UnixEnterMutex(){ -#ifdef SQLITE_UNIX_THREADS - pthread_mutex_lock(&mutexAux); - if( !mutexOwnerValid || !pthread_equal(mutexOwner, pthread_self()) ){ - pthread_mutex_unlock(&mutexAux); - pthread_mutex_lock(&mutexMain); - assert( inMutex==0 ); - assert( !mutexOwnerValid ); - pthread_mutex_lock(&mutexAux); - mutexOwner = pthread_self(); - mutexOwnerValid = 1; - } - inMutex++; - pthread_mutex_unlock(&mutexAux); -#else - inMutex++; -#endif -} -void sqlite3UnixLeaveMutex(){ - assert( inMutex>0 ); -#ifdef SQLITE_UNIX_THREADS - pthread_mutex_lock(&mutexAux); - inMutex--; - assert( pthread_equal(mutexOwner, pthread_self()) ); - if( inMutex==0 ){ - assert( mutexOwnerValid ); - mutexOwnerValid = 0; - pthread_mutex_unlock(&mutexMain); - } - pthread_mutex_unlock(&mutexAux); -#else - inMutex--; -#endif -} - -/* -** Return TRUE if the mutex is currently held. -** -** If the thisThrd parameter is true, return true only if the -** calling thread holds the mutex. If the parameter is false, return -** true if any thread holds the mutex. -*/ -int sqlite3UnixInMutex(int thisThrd){ -#ifdef SQLITE_UNIX_THREADS - int rc; - pthread_mutex_lock(&mutexAux); - rc = inMutex>0 && (thisThrd==0 || pthread_equal(mutexOwner,pthread_self())); - pthread_mutex_unlock(&mutexAux); - return rc; -#else - return inMutex>0; -#endif -} - -/* -** Remember the number of thread-specific-data blocks allocated. -** Use this to verify that we are not leaking thread-specific-data. -** Ticket #1601 -*/ -#ifdef SQLITE_TEST -int sqlite3_tsd_count = 0; -# ifdef SQLITE_UNIX_THREADS - static pthread_mutex_t tsd_counter_mutex = PTHREAD_MUTEX_INITIALIZER; -# define TSD_COUNTER(N) \ - pthread_mutex_lock(&tsd_counter_mutex); \ - sqlite3_tsd_count += N; \ - pthread_mutex_unlock(&tsd_counter_mutex); -# else -# define TSD_COUNTER(N) sqlite3_tsd_count += N -# endif -#else -# define TSD_COUNTER(N) /* no-op */ -#endif - -/* -** If called with allocateFlag>0, then return a pointer to thread -** specific data for the current thread. Allocate and zero the -** thread-specific data if it does not already exist. -** -** If called with allocateFlag==0, then check the current thread -** specific data. Return it if it exists. If it does not exist, -** then return NULL. -** -** If called with allocateFlag<0, check to see if the thread specific -** data is allocated and is all zero. If it is then deallocate it. -** Return a pointer to the thread specific data or NULL if it is -** unallocated or gets deallocated. -*/ -ThreadData *sqlite3UnixThreadSpecificData(int allocateFlag){ - static const ThreadData zeroData = {0}; /* Initializer to silence warnings - ** from broken compilers */ -#ifdef SQLITE_UNIX_THREADS - static pthread_key_t key; - static int keyInit = 0; - ThreadData *pTsd; - - if( !keyInit ){ - sqlite3OsEnterMutex(); - if( !keyInit ){ - int rc; - rc = pthread_key_create(&key, 0); - if( rc ){ - sqlite3OsLeaveMutex(); - return 0; - } - keyInit = 1; - } - sqlite3OsLeaveMutex(); - } - - pTsd = pthread_getspecific(key); - if( allocateFlag>0 ){ - if( pTsd==0 ){ - if( !sqlite3TestMallocFail() ){ - pTsd = sqlite3OsMalloc(sizeof(zeroData)); - } -#ifdef SQLITE_MEMDEBUG - sqlite3_isFail = 0; -#endif - if( pTsd ){ - *pTsd = zeroData; - pthread_setspecific(key, pTsd); - TSD_COUNTER(+1); - } - } - }else if( pTsd!=0 && allocateFlag<0 - && memcmp(pTsd, &zeroData, sizeof(ThreadData))==0 ){ - sqlite3OsFree(pTsd); - pthread_setspecific(key, 0); - TSD_COUNTER(-1); - pTsd = 0; - } - return pTsd; -#else - static ThreadData *pTsd = 0; - if( allocateFlag>0 ){ - if( pTsd==0 ){ - if( !sqlite3TestMallocFail() ){ - pTsd = sqlite3OsMalloc( sizeof(zeroData) ); - } -#ifdef SQLITE_MEMDEBUG - sqlite3_isFail = 0; -#endif - if( pTsd ){ - *pTsd = zeroData; - TSD_COUNTER(+1); - } - } - }else if( pTsd!=0 && allocateFlag<0 - && memcmp(pTsd, &zeroData, sizeof(ThreadData))==0 ){ - sqlite3OsFree(pTsd); - TSD_COUNTER(-1); - pTsd = 0; - } - return pTsd; -#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. -*/ -int sqlite3UnixCurrentTime(double *prNow){ -#ifdef NO_GETTOD - time_t t; - time(&t); - *prNow = t/86400.0 + 2440587.5; -#else - struct timeval sNow; - struct timezone sTz; /* Not used */ - gettimeofday(&sNow, &sTz); - *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; -} - -#endif /* OS_UNIX */ |