diff options
Diffstat (limited to 'libc/misc/file')
| -rw-r--r-- | libc/misc/file/Makefile | 2 | ||||
| -rw-r--r-- | libc/misc/file/lockf64.c | 85 |
2 files changed, 86 insertions, 1 deletions
diff --git a/libc/misc/file/Makefile b/libc/misc/file/Makefile index bb0ea02d8..ed31037bb 100644 --- a/libc/misc/file/Makefile +++ b/libc/misc/file/Makefile @@ -24,7 +24,7 @@ TOPDIR=../../../ include $(TOPDIR)Rules.mak -CSRC=lockf.c +CSRC=lockf.c lockf64.c COBJS=$(patsubst %.c,%.o, $(CSRC)) OBJS=$(COBJS) diff --git a/libc/misc/file/lockf64.c b/libc/misc/file/lockf64.c new file mode 100644 index 000000000..673d11397 --- /dev/null +++ b/libc/misc/file/lockf64.c @@ -0,0 +1,85 @@ +/* Copyright (C) 1994, 1996, 1997, 1998, 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <sys/types.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> +#include <string.h> + +#ifdef __NR_fcntl64 +#define flock flock64 +#define fcntl fcntl64 +#define F_GETLK F_GETLK64 +#define F_SETLK F_SETLK64 +#endif + +/* lockf is a simplified interface to fcntl's locking facilities. */ + +int lockf64 (int fd, int cmd, off64_t len64) +{ + struct flock fl; + off_t len = (off_t) len64; + + if (len64 != (off64_t) len) + { + /* We can't represent the length. */ + __set_errno(EOVERFLOW); + return -1; + } + + memset((char *) &fl, '\0', sizeof (fl)); + + /* lockf is always relative to the current file position. */ + fl.l_whence = SEEK_CUR; + fl.l_start = 0; + fl.l_len = len; + + switch (cmd) + { + case F_TEST: + /* Test the lock: return 0 if FD is unlocked or locked by this process; + return -1, set errno to EACCES, if another process holds the lock. */ + fl.l_type = F_RDLCK; + if (fcntl (fd, F_GETLK, &fl) < 0) + return -1; + if (fl.l_type == F_UNLCK || fl.l_pid == getpid ()) + return 0; + __set_errno(EACCES); + return -1; + + case F_ULOCK: + fl.l_type = F_UNLCK; + cmd = F_SETLK; + break; + case F_LOCK: + fl.l_type = F_WRLCK; + cmd = F_SETLKW; + break; + case F_TLOCK: + fl.l_type = F_WRLCK; + cmd = F_SETLK; + break; + + default: + __set_errno(EINVAL); + return -1; + } + + return fcntl(fd, cmd, &fl); +} |