diff options
Diffstat (limited to 'source/locking/locking.c')
| -rw-r--r-- | source/locking/locking.c | 134 |
1 files changed, 132 insertions, 2 deletions
diff --git a/source/locking/locking.c b/source/locking/locking.c index 6ff3ab5d125..78661d69706 100644 --- a/source/locking/locking.c +++ b/source/locking/locking.c @@ -2,7 +2,7 @@ Unix SMB/Netbios implementation. Version 1.9. Locking functions - Copyright (C) Andrew Tridgell 1992-1995 + Copyright (C) Andrew Tridgell 1992-1996 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -20,7 +20,6 @@ */ #include "includes.h" -#include "loadparm.h" extern int DEBUGLEVEL; extern connection_struct Connections[]; extern files_struct Files[]; @@ -29,6 +28,137 @@ pstring share_del_pending=""; /**************************************************************************** +routine to do file locking +****************************************************************************/ +BOOL fcntl_lock(int fd,int op,uint32 offset,uint32 count,int type) +{ +#if HAVE_FCNTL_LOCK + struct flock lock; + int ret; + +#if 1 + uint32 mask = 0xC0000000; + + /* make sure the count is reasonable, we might kill the lockd otherwise */ + count &= ~mask; + + /* the offset is often strange - remove 2 of its bits if either of + the top two bits are set. Shift the top ones by two bits. This + still allows OLE2 apps to operate, but should stop lockd from + dieing */ + if ((offset & mask) != 0) + offset = (offset & ~mask) | ((offset & mask) >> 2); +#else + unsigned long mask = ((unsigned)1<<31); + + /* interpret negative counts as large numbers */ + if (count < 0) + count &= ~mask; + + /* no negative offsets */ + offset &= ~mask; + + /* count + offset must be in range */ + while ((offset < 0 || (offset + count < 0)) && mask) + { + offset &= ~mask; + mask = mask >> 1; + } +#endif + + + DEBUG(5,("fcntl_lock %d %d %d %d %d\n",fd,op,(int)offset,(int)count,type)); + + lock.l_type = type; + lock.l_whence = SEEK_SET; + lock.l_start = (int)offset; + lock.l_len = (int)count; + lock.l_pid = 0; + + errno = 0; + + ret = fcntl(fd,op,&lock); + + if (errno != 0) + DEBUG(3,("fcntl lock gave errno %d (%s)\n",errno,strerror(errno))); + + /* a lock query */ + if (op == F_GETLK) + { + if ((ret != -1) && + (lock.l_type != F_UNLCK) && + (lock.l_pid != 0) && + (lock.l_pid != getpid())) + { + DEBUG(3,("fd %d is locked by pid %d\n",fd,lock.l_pid)); + return(True); + } + + /* it must be not locked or locked by me */ + return(False); + } + + /* a lock set or unset */ + if (ret == -1) + { + DEBUG(3,("lock failed at offset %d count %d op %d type %d (%s)\n", + offset,count,op,type,strerror(errno))); + + /* perhaps it doesn't support this sort of locking?? */ + if (errno == EINVAL) + { + DEBUG(3,("locking not supported? returning True\n")); + return(True); + } + + return(False); + } + + /* everything went OK */ + DEBUG(5,("Lock call successful\n")); + + return(True); +#else + return(False); +#endif +} + +/******************************************************************* +lock a file - returning a open file descriptor or -1 on failure +The timeout is in seconds. 0 means no timeout +********************************************************************/ +int file_lock(char *name,int timeout) +{ + int fd = open(name,O_RDWR|O_CREAT,0666); + time_t t=0; + if (fd < 0) return(-1); + +#if HAVE_FCNTL_LOCK + if (timeout) t = time(NULL); + while (!timeout || (time(NULL)-t < timeout)) { + if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)) return(fd); + msleep(LOCK_RETRY_TIMEOUT); + } + return(-1); +#else + return(fd); +#endif +} + +/******************************************************************* +unlock a file locked by file_lock +********************************************************************/ +void file_unlock(int fd) +{ + if (fd<0) return; +#if HAVE_FCNTL_LOCK + fcntl_lock(fd,F_SETLK,0,1,F_UNLCK); +#endif + close(fd); +} + + +/**************************************************************************** utility function called to see if a file region is locked ****************************************************************************/ BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset) |