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authorEric Andersen <andersen@codepoet.org>2003-01-10 03:32:11 +0000
committerEric Andersen <andersen@codepoet.org>2003-01-10 03:32:11 +0000
commitacf6afe5fdeed2c6e884ee205330640cc64b3265 (patch)
treee104dc2f2239e1582721e8caa2b2b6cd1e5225a6 /libc/misc/file/lockf64.c
parent2ace214a9f5d6a6d229558849ed77063d7cb89c0 (diff)
Implement lockf64
-Erik
Diffstat (limited to 'libc/misc/file/lockf64.c')
-rw-r--r--libc/misc/file/lockf64.c85
1 files changed, 85 insertions, 0 deletions
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);
+}